Northern Regions. Flood Risk Management Plan 2011 FLOOD RISK MANAGEMENT PLAN
MINISTRY OF REGIONAL AND LOCAL GOVERNMENT, HOUSING AND RURAL DEVELOPMENT OCTOBER/2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 1 Northern Regions. Flood Risk Management Plan 2011
Prepared by:
Architect: Msc. Carlos V. Tamayo Milanés Geographer: Msc. Armando C. Muñiz González Geographer: Félix D. Hernández Rubio Architect: Abel Gil Concepción FLOOD RISK MANAGEMENT PLAN
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel GGilil PagePaPaggee 2 Northern Regions. Flood Risk Management Plan 2011
“There certainly is a need to find a lasting solution to people who are continuously affected by floods due to their location in the flood prone areas.”
(Source: Report on the 2009 flood disaster response, page 10). FLOOD RISK MANAGEMENT PLAN
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel GGilil PagePaPaggee 3 Northern Regions. Flood Risk Management Plan 2011
TABLE OF CONTENTS
No. Aspect Page ABBREVIATIONS AND ACRONYMS 7 GLOSSARY OF TERMS 9 EXECUTIVE SUMMARY 12 1.0- GENERAL INTRODUCTION 14 2.0- BACKGROUND OF THE PLAN 16 2.1- Flooding. General Approach 16 2.1.1- Key Concepts 16 2.1.2- Impacts of Flooding 16 2.1.3- Flood Risk 18 2.1.4- Flood Risk Assessment 19 2.2- The Namibian Experience 20 2.2.1- Previous Studies 20 2.2.2- The Cuban Assessment 21 2.3- The Town Flood Risk Management Plans 21 2.3.1- Objectives 22 2.3.2 Key Principles 22 2.4- Risk Maps 22 3.0- SITUATION ANALYSIS. NORTHERN REGIONS 24 3.1- General Characterization 24 3.2- Environmental Impact 24 3.2.1- Graphic Examples of the Main Environmental Impacts 29 3.3- Situation Analysis 31 3.3.1- Main Natural Hazards 31 3.3.2- Vulnerability 31 3.3.3- Coping Ability 32 4.0- SITUATION ANALYSIS PER REGIONS 34 4.1- CAPRIVI REGION 34 4.1.1- Regional Context 34 4.1.1.1- General Characterization 34 4.1.1.2- Situation Analysis 36 4.1.2- Katima Mulilo Town 43 4.1.2.1- General Characterization 43 4.1.2.2- Situation Analysis 48 4.2- KAVANGO REGION 54 4.2.1- Regional Context 54 4.2.1.1- General Characterization 54 4.2.1.2- Situation Analysis 57 4.2.2- Rundu Town 65 4.2.2.1- General Characterization 65 4.2.2.2- Situation Analysis 67 4.2.3- Nkurenkuru Town 73 4.2.3.1- General Characterization 73 4.2.3.2- Situation Analysis 75
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No. Aspect Page 4.3- CUVELAI BASIN 81 4.3.1- Territorial Context 81 4.3.1.1- General Characterization 81 4.3.1.2- Situation Analysis 83 4.3.2- OSHANA REGION 99 4.3.2.1- Regional Context 99 4.3.2.1.1- General Characterization 99 4.3.2.1.2- Situation Analysis 100 4.3.2.2- Ondangwa Town 105 4.3.2.2.1- General Characterization 105 4.3.2.2.2- Situation Analysis 107 4.3.2.3- Ongwediva Town 112 4.3.2.3.1- General Characterization 112 4.3.2.3.2- Situation Analysis 114 4.3.3- OHANGWENA REGION 120 4.3.3.1- Regional Context 120 4.3.3.1.1- General Characterization 120 4.3.3.1.2- Situation Analysis 122 4.3.3.2- Helao Nafidi Town 126 4.3.3.2.1- General Characterization 126 4.3.3.2.2- Situation Analysis 127 4.3.4- OMUSATI REGION 137 4.3.4.1- Regional Context 137 4.3.4.1.1- General Characterization 137 4.3.4.1.2- Situation Analysis 140 4.3.4.2- Outapi Town 143 4.3.4.2.1- General Characterization 143 4.3.4.2.2- Situation Analysis 146 4.3.4.3- Okalongo Settlement Area 154 4.3.4.3.1- General Characterization 154 4.3.4.3.2- Situation Analysis 156 4.3.4.4- Oshikuku Town 162 4.3.4.4.1- General Characterization 162 4.3.4.4.2- Situation Analysis 164 4.3.4.5- Okahao Town 170 4.3.4.5.1- General Characterization 170 4.3.4.5.2- Situation Analysis 172 5.0- GENERAL PROPOSALS. NORTHERN REGIONS 178 5.1- General Regional Proposals 178 5.2- General Proposals for Urban Areas 180 6.0- SPECIFIC PROPOSALS PER REGIONS AND URBAN AREAS 184 6.1- CAPRIVI REGION 184 6.1.1- Regional Proposals 184 6.1.2- Katima Mulilo Town Proposals 186 6.1.2.2- Katima Mulilo Contingency Plan 188 6.2- KAVANGO REGION 197 6.2.1- Regional Proposals 197
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No. Aspect Page 6.2.2- Rundu Town Proposals 199 6.2.2.2- Rundu Town Contingency Plan 202 6.2.3- Nkurenkuru Town Proposals 211 6.2.3.2- Nkurenkuru Town Contingency Plan 212 6.3- CUVELAI BASIN 221 6.3.1- General Proposals 221 6.3.2- OSHANA REGION 233 6.3.2.1- Regional Proposals 233 6.3.2.2- Ondangwa Town Proposals 237 6.3.2.2.2- Ondangwa Town Contingency Plan 241 6.3.2.3- Ongwediva Town Proposals 250 6.3.2.3.2- Ongwediva Town Contingency Plan 251 6.3.3- OHANGWENA REGION 260 6.3.3.1- Regional Proposals 260 6.3.3.2- Helao Nafidi Town Proposals 262 6.3.3.2.2- Helao Nafidi Town Contingency Plan 263 6.3.4- OMUSATI REGION 272 6.3.4.1- Regional Proposals 272 6.3.4.2- Outapi Town Proposals 274 6.3.4.2.2- Outapi Town Contingency Plan 276 6.3.4.3- Okalongo Town Proposals 285 6.3.4.3.2- Okalongo Town Contingency Plan 286 6.3.4.4- Oshikuku Town Proposals 298 6.3.4.4.2- Oshikuku Town Contingency Plan 299 6.3.4.5- Okahao Town Proposals 308 6.3.4.5.2- Okahao Town Contingency Plan 309 7.0- OSHAKATI CONCEPT MASTER PLAN. PHASE I 318 7.1- Proposal of Implementation 318 7.2- Time framework 321 7.3- Action Plan 323 7.4- Construction of a dike around Oshakati Town 325 7.4.1- Standard Summary Project 325 7.4.2- Terms of Reference 329 8.0- PROPOSALS FOR FUTURE PLANNING. Study Case: Outapi 345 8.1- Flood Regulations for existing urban area 347 9.0- FLOOD RISK MANAGEMENT PLAN. ACTION PLAN 370 10.0- FINAL CONCLUSIONS 374 11.0- BIBLIOGRAPHY 376
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ABBREVIATIONS AND ACRONYMS ARC Association of Regional Councils BMC Basin Management Committee CBD Central Business District CBM Community Based Management CBO Community Based Organization DEA Directorate of Environmental Affairs DRWS Directorate of Rural Water Supply DWA Department of Water Affairs EIA Environmental Impact Assessment EMIS Education Management Information System EMP Environmental Management Plan EPZ Export Processing Zone ESIA Environmental and Social Impact Assessment FRMP Flood Risk Management Plans GDP Gross Domestic Product GIS Geographical Information Systems GRN Government of the Republic of Namibia GROWAS Groundwater Information System GSN Geological Survey of Namibia IRBM Integrated River Basin Management LA Local Authorities MAWF Ministry of Agriculture, Water Affairs and Forestry MDG Millennium Developmental Goals MET Ministry of Environment and Tourism MFMR Ministry of Fisheries and Marine Resources MRLGHRD Ministry of Regional and Local Government, Housing and Rural Development MLR Ministry of Lands and Resettlement MME Ministry of Mines and Energy MMSD Mining, Minerals and Sustainable Development Project MoHSS Ministry of Health and Social Services MRA Marine Resources Act NAD Namibian Dollar
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NAMCOL Namibian College of Open Learning NamPower Namibia Power Corporation NamWater Namibia Water Corporation Ltd NDP National Development Plan NGO Non Governmental Organization NHC National Heritage Council NHE National Housing Enterprise NMS Namibia Meteorological Service NPC National Planning Commission NTB Namibia Tourism Board NWP National Water Policy PA Protected Area RC Regional Council SADC Southern African Development Community SDI Shack Dwellers International SEA Strategic Environmental Assessment SEMP Strategic Environmental Management Plan SIA Social Impact Assessment SPC Stubenrauch Planning Consultants cc TDS Total Dissolved Solids TFRMP Town Flood Risk Management Plans ToR Terms of Reference UN United Nations UNAM University of Namibia UNCHS United Nations Centre for Human Settlements UNDP United Nations Development Program USD United States Dollar
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GLOSSARY OF TERMS Breach of defenses: A structural failure at a flood defense allowing water to flow through. Catchment: The area that is drained by a river or artificial drainage system. Climate change: Long-term variations in global temperature and weather patterns, which occur both naturally and as a result of human activity, primarily through greenhouse gas emissions. Consequence of flooding: Health, social, economic and environmental effects of flooding, some of which can be assessed in monetary terms, while other less tangible impacts are more difficult to quantify. Consequences depend on the hazards associated with the flooding and the vulnerability of receptors. Conveyance function: When a river overflows its banks, it continues to flow over the flood plain, conveying water down-stream, as well as storing water where the flood plain may be obstructed and releasing it slowly. Core of an urban settlement: The core area of a city, town or village which acts as a centre for a broad range of employment, retail, community, residential and transport functions. Detailed flood risk assessment: A methodology to assess flood risk issues in sufficient detail and to provide a quantitative appraisal of flood hazard and potential risk to an existing or proposed development, of its potential impact on flood elsewhere and of the effectiveness of any proposed measures. Environmental Impact Assessment (EIA): EIA is a legislative procedure used for identifying the environmental effects of development projects to be applied to the assessment of the environmental effects of certain public and private projects which are likely to have significant effects on the environment. Flash Flood: A flash flood is a rapid flooding of an area of land as a result of intense or extreme rainfall events or failure of infrastructure designed to store or carry water or protect against flooding and is distinguished from general flooding by the sudden onset. Flooding (or inundation): Flooding is the overflowing of water onto land that is normally dry. It may be caused by overtopping or breach of banks or defenses, inadequate or slow drainage of rainfall, underlying groundwater levels or blocked drains and sewers. It presents a risk only when people, human assets and ecosystems are present in the areas that flood. Flood defense: A man-made structure (e.g. embankment, bund, sluice gate, reservoir or barrier) designed to prevent flooding of areas adjacent to the defense. Flood-detention reservoirs: An embanked area designed to hold floodwater from areas upstream and release it slowly to reduce flooding downstream. Embankments may be constructed across the river or adjacent to the river, with flood flows being diverted into the reservoir area. Flooding from artificial drainage systems: This occurs when flow entering a system, such as an urban storm water drainage system, exceeds its discharge capacity, becomes blocked or when the system cannot discharge due to a high water level in the receiving watercourse.
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Flood hazard: The features of flooding which have harmful impacts on people, property or the environment (such as the depth of water, speed of flow, rate of onset, duration, water quality etc). Flood hazard assessment: An assessment of the hazards that would arise from flooding, e.g. identifying where flooding would occur, how deep the water would be, how fast it would flow, how rapidly would it rise and how long it would remain. Floodplain: A floodplain is any low-lying area of land next to a river or stream, which is susceptible to partial or complete inundation by water during a flood event. Flood risk: An expression of the combination of the flood probability or likelihood and the magnitude of the potential consequences of the flood event. Flood risk assessment: It can be undertaken at any scale from the national down to the individual site and comprises 3 stages: Flood risk identification, initial flood risk assessment and detailed flood risk assessment. Flood risk identification: A desk-based study to identify whether there may be any flooding or surface water management issues related to a plan area or proposed development site that may warrant further investigation. Flood Risk Management (FRM): FRM combines the function of mitigating and monitoring flood risks and may include pre-flood, flood event or post-flood activities. Flood Risk Management Plans (FRMP): Plans which are developed in accordance with national flood policy, which provide the strategic direction for flood risk management decisions in a catchment. These will describe a range of traditional river or coastal defenses to non-structural responses such as flood warning and resilience measures at property level. Flood storage: The temporary storage of excess run-off or river flow in ponds, basins, reservoirs or on the floodplain. Flood zones: A geographic area for which the probability of flooding from rivers, oshanas or heavy rain is within a particular range as defined within this Plan. Fluvial flooding: Flooding from a river or other watercourse. Groundwater flooding: Flooding caused by groundwater escaping from the ground when the water table rises to or above ground level. Indicative Floodplain Map (IFM): A map that delineates the areas estimated to be at risk of flooding during an event of specified flood probability. Being indicative, such maps only give an indication of the areas at risk but, due to the scale and complexity of the exercise, cannot be relied upon to give precise information in relation to individual sites. Initial flood risk assessment: A qualitative or semi-quantitative study to confirm sources of flooding that may affect a plan area or proposed development site, to appraise the adequacy of existing information, to provide a qualitative appraisal of the risk of flooding to development, including the scope of possible mitigation measures, and the potential impact of development on flooding elsewhere, and to determine the need for further detailed assessment.
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Inland flooding: Any flooding away from the sea, the primary cause of which is prolonged and/or intense precipitation (or the failure of water-retaining infrastructure, such as burst water pipes or dam breaks). Likelihood (probability) of flooding: A general concept relating to the chance of an event occurring. Likelihood is generally expressed as a probability or a frequency of a flood of a given magnitude or severity occurring or being exceeded in any given year. It is based on the average frequency estimated, measured or extrapolated from records over a large number of years and is usually expressed as the chance of a particular flood level being exceeded in any one year. For example, a 1 in 100 or 1% flood is that which would, on average, be expected to occur once in 100 years, though it could happen at any time. Mitigation measures: Elements of a development design which may be used to manage flood risk to a development, either by reducing the incidence of flooding both to the development and as a result of it and/or by making the development more resistant and/or resilient to the effects of flooding. Pathways: These provide the connection between a particular source (e.g. high river or tide level) and the receptor that may be harmed (e.g. property). In flood risk management, pathways are often ‘blocked’ by barriers, such as flood defense structures, or otherwise modified to reduce the incidence of flooding. Pluvial flooding: Usually associated with convective summer thunderstorms or high intensity rainfall cells within longer duration events, pluvial flooding is a result of rainfall- generated overland flows which arise before run-off enters any watercourse or sewer. The intensity of rainfall can be such that the run-off totally overwhelms surface water and underground drainage systems. Receptors: Things that may be harmed by flooding (e.g. people, houses, buildings or the environment). Residual risk: The risk which remains after all risk avoidance, substitution and mitigation measures have been implemented, on the basis that such measures can only reduce risk, not eliminate it. Site-specific Flood Risk Assessment: An examination of the risks from all sources of flooding of the risks to and potentially arising from development on a specific site, including an examination of the effectiveness and impacts of any control or mitigation measures to be incorporated in that development. Source: Source refers to a source of hazard (e.g. the sea, heavy rainfall). Source-Pathway-Receptor Model: For there to be flood risk, the three components of flood risk - the source of the hazard, the receptors affects by the hazard and the mechanism of transfer between the two - must all exist. Vulnerability: The resilience of a particular group of people or types of property or habitats, ecosystems or species to flood risk, and their ability to respond to a hazardous condition and the damage or degree of impact they are likely to suffer in the event of a flood. For example, elderly people may be more likely to suffer injury, and be less able to evacuate, in the event of a rapid flood than younger people.
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EXECUTIVE SUMMARY Flooding in Namibia has become a common phenomenon. Floods have had significant impacts in the affected areas including displacement of the population, the loss of life and livestock, destruction of homes and businesses, crops and the social infrastructure and generally impacting severely on the livelihoods of the affected populations. The present study has been prepared to identify and respond to emerging humanitarian needs in the five most affected regions, with deeper approaches in selected towns and settlement areas. The causes of the flood disasters were the above normal rainfall received in the northern central and eastern regions of Namibia, southern Angola and Zambia and a series of risk conditions such as uncontrolled urban development and settlements on river beds and flood prone areas. The main objective of the study was the formulation of general and specific actions and recommendations for the short, medium and long term, to be implemented in the northern regions of the country to attenuate flood vulnerabilities, including specific studies for the affected urban areas, as well as the identification of other risk management related technical studies to be carried out within the framework of the existing cooperation between Cuba and Namibia. A detailed examination of the existing situation in all the affected territory is carried out, including specific analyses for each one of the five affected regions and the more affected urban areas, incorporating general and specific actions and recommendations. At the same time vulnerability studies for the ten towns more affected by the floods were prepared, with emphasis in the environmental analysis with respect to flood risks and vulnerabilities. This work is aimed at the preparation, reformulation and/or improvement of the existing urban plans, taking into account the existing situation, considering the areas required for the future growth, the relocation of the population living in vulnerable areas and the formalization of the informal settlements located within urban boundaries. The study incorporates, in addition, a contingency plan for the management of flood risks in every settlement. The study carried out by the Cuban experts had the full technical and material support from the Ministry of Regional and Local Government, Housing and Rural Development, as well as from specialists of other local and national institutions and agencies.
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GENERAL INTRODUCTION FLOOD RISK MANAGEMENT PLAN
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1.0- GENERAL INTRODUCTION During the years 2008, 2009 and 2011flood events seriously affected the Northern part of the Republic of Namibia. The disaster influenced mostly on 5 of the 13 regions of the country (Caprivi, Kavango, Ohangwena, Oshana and Omusati) causing severe damage to the production bases of the local population, destroying the wage based as well as natural resource based livelihoods in both rural and urban areas. The flood events strongly affected the urban and semi-urban lowland flood prone areas, causing extensive damages to buildings and infrastructures. The causes of the flood disasters have been the above normal rainfall received in the northern central and eastern regions of Namibia, southern Angola and Zambia, the high inflows in the Cuvelai basin, Kwando and Kavango Rivers with flood waters from southern Angola. The floods in the Caprivi region were due to the high inflows of the Zambezi River from heavy rain falls in Zambia, and a series of risk conditions such as uncontrolled urban development and settlements on river beds and flood prone areas. Although historically flooding in Cuvelai basin, Kavango, Zambezi and Chobe rivers have been occurring, the 2011 floods has so far been the largest in term of the geographical area affected. The extensive nature of the impact of the floods has been attributed to increased population settled in the Cuvelai basin and the flood plain in Caprivi and Kavango regions, road and rail construction and emerging informal settlements in peri- urban areas that interfered with natural rivers flows. Flooding in some urban areas in Ondangwa, Outapi, Helao Nafidi and Katima Mulilo is mainly due to inadequate storm water drainage. The other major risk factors are the construction of public and private infrastructure such as railway lines, roads, homes and social services in flood prone areas. There certainly is a need to find a lasting solution to people who are continuously affected by floods due to their location in the flood prone areas.
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BACKGROUND OF THE PLAN FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 15 Northern Regions. Flood Risk Management Plan 2011
2.0- BACKGROUND OF THE PLAN
2.1- Flooding. General approach Flooding is a natural process that can happen at any time in a wide variety of locations. According to the international experience, flooding from the sea and from rivers is probably best known but prolonged, intense and localized rainfall can also cause sewer flooding, overland flow and groundwater flooding. Flooding has significant impacts on human activities; it can threaten people’s lives, their property and the environment. Assets at risk can include housing, transport and public service infrastructure, and commercial, industrial and agricultural enterprises. The health, social, economic and environmental impacts of flooding can be significant and have a wide community impact. The frequency, pattern and severity of flooding are expected to increase as a result of climate change. Development can also exacerbate the problems of flooding by accelerating and increasing surface water run-off, altering watercourses and removing floodplain storage.
2.1.1- Key concepts Flooding is a natural process and can happen at any time in a wide variety of locations. It constitutes a temporary covering of land by water and presents a risk only when people, their property and/or environmental assets are present in the area which floods. Understanding flood risk is an essential step in managing the associated impacts of flooding and in making informed decisions in addressing such impacts. The science is complex, and datasets are currently being enhanced by detailed studies. Therefore, these Plans recommend a staged approach. High level regional appraisals, strategic assessments at regional/town level and more detailed site specific assessments of flood risk, taking account of the impacts of climate change, will need to be carried out by regional, local authorities and developers respectively.
2.1.2- Impacts of Flooding Impacts on people and communities – Flooding can cause physical injury, illness and loss of life. Deep, fast flowing or rapidly rising flood waters can be particularly dangerous. For example, even shallow water flowing at 2 meters per second (m/sec) can knock children and many adults off their feet, and vehicles can be moved by flowing water of only 300mm depth. The risks increase if the floodwater is carrying debris. Some of these impacts may be immediate, the most significant being drowning or physical injury due to being swept away by floods. Floodwater contaminated by sewage or other pollutants (e.g. chemicals stored in garages or commercial properties) is particularly likely to cause such illnesses, either directly as a result of contact with the polluted floodwater or indirectly as a result of sediments left behind. Flood water may also hide other hazards for wading pedestrians, such as manhole openings where the covers have been lifted by flood flows. Those most likely to be at risk are those
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Northern Regions. Flood Risk Management Plan 2011 outdoors on foot or in a vehicle, in a tent or caravan, or in a building, such as a single-storey bungalow or below ground in a basement. The impact on people and communities as a result of the stress and trauma of being flooded, or even of being under the threat of flooding, can be immense. Flooding can cause many potential health problems. While storm water is mixing up with sewerage water, it is likely that pools of water will be contaminated by such bacteria as fecal coliform, clostridium viable, som. coliphage and vibrio chlolerae. When contaminated water is used for human consumption, these bacteria may cause severe diseases such as diarrhea and cholera. After the rains, mosquitoes begin to nest in stable pools of water. As mentioned before, floodwater is not ever pure and it contains always a potential health risk as well as suitable platform for breeding malaria mosquitoes. Furthermore, floodwater can move animal carcasses and other dangerous objects from one place to another. In any case, disease infections are probable through human contacts. Long-term impacts can arise due to chronic illnesses and the stress associated with being flooded and the lengthy recovery process. The ability of people to respond and recover from a flood can vary. Vulnerable people, such as those who are old, disabled or have a long-term illness, are less able to cope with floods than others. Some people may have difficulty in replacing household items damaged in a flood and may lack the financial means to recover and maintain acceptable living conditions after a flood. Impacts on property - Flooding can cause severe damage to properties. Floodwater is likely to damage internal finishes, contents and electrical and other services and possibly cause structural damage. The physical effects can have significant long-term impacts, with re-occupation sometimes not being possible for over a year. The costs of flooding are increasing, partly due to increasing amounts of electrical and other equipment within developments. Sea-water flooding may cause additional damage due to corrosion. Impacts on Infrastructure - The damage flooding can cause to businesses and infrastructure, such as transport or utilities like electricity and water supply can have significant detrimental impacts on local and regional economies. Flooding of primary roads or railways can deny access to large areas beyond those directly affected by the flooding for the duration of the flood event, as well as causing damage to the road or railway itself. Flooding of water distribution infrastructure such as pumping stations or of electricity sub- stations can result in loss of water or power supply over large areas. This can magnify the impact of flooding well beyond the immediate community. The long-term closure of businesses, for example, can lead to job losses and other economic impacts. Impacts on the environment - Significant detrimental environmental effects of flooding can include soil erosion, bank erosion, land sliding and damage to vegetation as well as the impacts on water quality, habitats and flora and fauna caused by bacteria and other pollutants carried by flood water. Flooding can however play a beneficial role in natural habitats. Many wetland habitats are dependent on annual flooding for their sustainability and can contribute to the storage of flood waters to reduce flood risk elsewhere.
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2.1.3- Flood Risk Understanding flood risk is a key step in managing the impacts of flooding. Flood risk is a combination of the likelihood of flooding and the potential consequences arising. These Plans recommend a staged approach to flood risk assessment that covers both the likelihood of flooding and the potential consequences. There are two components of flood risk that must be considered in applying this guidance in a consistent manner: ! Likelihood of flooding is normally defined as the percentage probability of a flood of a given magnitude or severity occurring or being exceeded in any given year. For example, a 1% probability indicates the severity of a flood that is expected to be exceeded on average once in 100 years, i.e. it has a 1 in 100 (1%) chance of occurring in any one year. ! Consequences of flooding depend on the hazards associated with the flooding (e.g. depth of water, speed of flow, rate of onset, duration, wave-action effects, water quality), and the vulnerability of people, property and the environment potentially affected by a flood (e.g. the age profile of the population, the type of development, presence and reliability of mitigation measures etc). Flood risk is then normally expressed in terms of the following relationship: Flood risk = Likelihood of flooding x Consequences of flooding Flood risk can be measured in monetary terms, as a potential for loss of life or injury, as environmental impacts, or as combinations of all these indicators. Guiding proposed development to areas where the risks arising from inundation in terms of human impact, economic loss or potential environmental damage is minimized, is a key tenet of this guidance. The vulnerability of development to flooding depends on the nature of the development, its occupation and the construction methods used. For example, a sheltered housing complex would be more vulnerable than a retail unit. The classification of different land uses and types of development as highly vulnerable, less vulnerable and water-compatible is influenced primarily by the ability to manage the safety of people in flood events and the long-term implications for recovery of the function and structure of buildings. Transport and strategic utilities infrastructure can be particularly vulnerable to flooding because interruption of their function can have widespread effects well beyond the area that is flooded. This reinforces the need for decisions to locate development in areas at risk of flooding to be fully justified with regard to wider proper planning and sustainable development considerations.
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Northern Regions. Flood Risk Management Plan 2011
2.1.4- Flood Risk Assessment The assessment of flood risk requires an understanding of where the water comes from (i.e. the source), how and where it flows (i.e. the pathways) and the people and assets affected by it (i.e. the receptors). The principal sources are rainfall or higher than normal sea levels. The principal pathways are rivers, drains, sewers, overland flow and river and coastal floodplains and their defense assets. The receptors can include people, their property and the environment. All three elements must be examined as part of the flood risk assessment including the vulnerability and exposure of receptors to determine its potential consequences. Mitigation measures typically used in development management can reduce the impact on people and communities, for example, by blocking or impeding pathways but they have little or no effect on the sources of flooding. The planning process is primarily concerned with the location of receptors, taking appropriate account of potential sources and pathways that might put those receptors at risk. Risks to people, property and the environment should be assessed over the full range of probabilities, including extreme events. The flood risk assessment should cover all sources of flooding, including the effects of run-off from a development on flood risk both locally and beyond the development site. A staged approach should be adopted, carrying out only such appraisal and or assessment as is needed for the purposes of decision-making at the regional, development and local area plan levels, and also at the site specific level. The stages of appraisal and assessment are: Stage 1 Flood risk identification – to identify whether there may be any flooding or surface water management issues related to either the area of regional planning guidelines, development plans and LAP’s or a proposed development site that may warrant further investigation at the appropriate lower level plan or planning application levels; Stage 2 Initial flood risk assessment – to confirm sources of flooding that may affect a plan area or proposed development site, to appraise the adequacy of existing information and to scope the extent of the risk of flooding which may involve preparing indicative flood zone maps. Where hydraulic models exist, the potential impact of a development on flooding elsewhere and of the scope of possible mitigation measures can be assessed. In addition, the requirements of the detailed assessment should be scoped; and Stage 3 Detailed flood risk assessment – to assess flood risk issues in sufficient detail and to provide a quantitative appraisal of potential flood risk to a proposed or existing development or land to be zoned, of its potential impact on flood risk elsewhere and of the effectiveness of any proposed mitigation measures.
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2.2- The Namibian Experience The Republic of Namibia has implemented a National Policy for Disaster Risk Management to deal with flood events in different phases: prevention, preparedness, response and recovery. The National Disaster Risk Management Policy is grounded on five fundamental principles:
! Fundamental human rights and freedoms
! Humanitarian principles and codes of practices for humanitarian assistance
! The shift towards disaster risk reduction into development.
! Protecting sustainable development gains of Namibia by mainstream disaster risk reduction into development.
! Sustainable ecosystem and environmental management Nevertheless, there are insufficiencies in the implementation of this policy affecting the effective mitigation of vulnerabilities and disaster risks, especially in flood events, due to the lack of efficient regional and urban plans prepared especially to highly vulnerable regions, with an environmental approach.
2.2.1- Previous Studies After the flood events that took place in the Northern regions of the country during the years 2008 and 2009, a number of documents have been published by different agencies, which cover issues relevant to flooding. The key messages arising from these documents are that: ! Government recognizes the significance of flood risk and the need to integrate flood risk assessment and its management into the planning process in order to deliver a policy of avoidance or minimization of potential future flood risk, and as part of a range of responses to flooding including risk evaluation, flood forecasting and warning, emergency response systems and capital projects of an engineering nature; ! Proper planning and sustainable development may at the same time required in exceptional circumstances some development in areas of flood risk, provided that the issue of flood risk is managed appropriately; ! Implications for biodiversity should be considered at all stages of flood risk assessment and its management; ! Climate change is a dynamic process that requires a precautionary and flexible approach to ensure appropriate provision for, or adaptation to, its potential consequences; and ! Investment in flood risk management needs to be focused on the areas of greatest need through a strategically led flood risk management approach.
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2.2.2- The Cuban Assessment In the year 2009, a team of Cuban experts visited the five most affected Regions of the Northern part of the republic of Namibia by flood events during the years 2008 and 2009 and prepared a general report that recommended the continuation of the study, with the identification of ten human settlements considered as the most vulnerable to such natural disasters. As part of that recommendation, a Technical Assistance Project was signed between the Institute of Physical Planning of Cuba and the Ministry of Regional and Local Government, Housing and Rural Development of Namibia in order to prepare urban planning studies and contingency plans for each of the selected regions and urban areas, with emphasis in environmental analysis regarding risks and vulnerabilities to flood events. The planning studies are intended to the preparation, reformulation or completion of the urban plans, taking into account the existing situation at the beginning of the study, considering the required lands for new developments, relocation of population living in vulnerable areas and formalization of the informal settlements located within town boundaries. A development projection is included with proposed solutions through a realistic approach to the town’s specific problems. In order to comply with the agreement, a team of three Cuban experts of the Institute of Physical Planning were working in the country from October 2010 until December 2011. The team was assisted by the Ministry of Regional Local Government Housing and Rural Development (MRLGHRD), representing the Namibian government.
2.3- The Town Flood Risk Management Plans In order to mitigate the severe impacts of flooding witnessed in the years 2008, 2009 and 2011, this study incorporates Town Flood Risk Management Plans prepared to identify and respond to emerging humanitarian needs in selected towns and settlements located in the five most affected regions as a result of the foreseeable flooding incidence. These plans provide the strategic direction for flood risk management decisions in an affected urban area, from an examination of the risks from all sources of flooding (rivers, heavy rains, etc.) of the risks to and potentially arising from development on that specific site, including an examination of the effectiveness and environmental impacts of any control or mitigation measures to be incorporated in that development. These plans will describe a range of traditional flood defenses (canals, bridges, culverts, dikes, damns) to non-structural responses such as flood warning and resilience measures at property level. TFRMP combines the function of mitigating and monitoring flood risks and may include pre- flood, flood event or post-flood activities.
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2.3.1- Objectives The core objectives of the Plan are to: :: Avoid inappropriate development in areas at risk of flooding; :: Avoid new developments increasing flood risk elsewhere, including that which may arise from surface water run-off; :: Ensure effective management of residual risks for development permitted in floodplains; :: Avoid unnecessary restriction of national, regional or local economic and social growth; and :: Improve the understanding of flood risk among relevant stakeholders.
2.3.2- Key Principles In achieving the aims and objectives of the plan, the key principles that should be adopted by regional and local authorities, developers and community should be to: :: Avoid the risk, where possible, :: Substitute less vulnerable uses, where avoidance is not possible, and :: Mitigate and manage the risk, where avoidance and substitution are not possible.
2.4- Risk Maps In order to prepare Risk Maps for the selected regions and urban areas, it is necessary to identify the elements that composed the risk, the conditions that increase the vulnerability and the coping ability. Hazard: Floods due to high volume of water coming from the Cuvelai basin through the oshanas, overflow of existing rivers and heavy rains. Vulnerability: The vulnerability increases due to presence of high concentration of population living in flood prone areas, modification of the original characteristics of the natural water ways, lack or disregard of environmental impact assessments, fragility of building materials, lack of risk perception by local population, insufficient solutions to allow free water flow, lack of maintenance to natural water ways, lack of storm water drainage system in urban areas, etc. According to these elements the following classification is proposed: High Risk Zones: Areas located in flood prone areas with high vulnerability. Moderate Risk Zones: Flood prone areas (low lying areas) affected specially by rains with moderate vulnerability. Low Risk Zone: High lands and low lying areas with low vulnerability.
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SITUATION ANALYSIS FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 23 Northern Regions. Flood Risk Management Plan 2011
3.0- SITUATION ANALYSIS. NORTHERN REGIONS
3.1- General Characterization The northern regions considered within the study are Caprivi, Kavango, Ohangwena, Oshana and Omusati, covering a total area of 130 965 square kilometers. The population in the whole territory is estimated to be 1,025,973 representing over 50% of the total population of Namibia.
Region Total Population Rural Population Urban Population % total % total inhabitants inhabitants inhabitants region region Caprivi 87, 058 62,682 72 24,376 28 Kavango 257,347 185,290 72 72057 28 Oshana 176,586 121,844 69 54742 31 Omusati 243,658 241,221 99 2613 1 Ohangwena 261,324 258,711 99 16317 1 Total 1,025,973 869,748 84 170,105 16
The rural population is predominant in all the regions, especially in Omusati and Ohangwena. Nowadays there is a predominance of disperse population and housing and the existence of few settlements with concentrated population. Those settlements are not strong enough to attract and motivate disperse residents to immigrate to them. At the same time, there are other aspects such as local and family traditions, social integration, economic activities, and poverty status. In the Northern regions around 28% of all households’ incomes are from farming activities. In regions such as the Ohangwena (52%), Omusati (46%) and Kavango (52%) of all households derive their main incomes from farming, a combination of factors such as unreliable rainfall, moderate soils, low crop production inputs and low levels of agricultural technologies often result in low yields of coarse grains. With low yields, several households are unable to meet most of their basic needs and thus engage in a range of non farming activities for additional incomes. Common sources of income include sale of livestock, weaving traditional handcrafts, selling grass, roots, tubers and fruits from the veldt, sale of amarula oils, brewing local beer, and trading. Pensions, salaries and government grants are also sources of incomes for some categories of people. For those in urban informal settlements, the majority derive their incomes from a diverse range of activities such as casual labor, trading, tailoring, selling cooked food and traditional beer.
3.2 – Environmental Impact The Environmental Impact Assessment of the flood events on the northern regions should value the impacts on: ! Man, fauna and flora. ! Soils, air, water, climate and landscapes. ! Interactions between factors mentioned above, and
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! Livelihood and cultural heritage. Man depend of his environment, and it is a system of relations, where is not easy make any alteration of any element that belonged to it without to affect others perhaps more important than the previous one. There is a general trend to identify environment like things, while it really means relations. Environmental aspects to be considered Topography: All the regions are between 1000-1 500 m. of altitude, except the most eastern part of the Caprivi region with 500-1 000 m. above sea level.
Geology: Mostly characterized for the predominance of sand stone and calcrete, with soils red fersilitic sand and loam. Soils in the Cuvelai basin are generally nutrient-poor and are often saline. Soils: The main soils that occur in these regions are: Arenosols: Alluvial and other weakly developed soils (Low-Lying). - Dark alluvial sand and loam. - Mainly grayish. - Inland sands. - Alluvial enriched with organic material. Red fersialitic sand and loam. Solonetzic and planosoles soils with sandy A – horizon. Hydrology: All the rivers of the interior are episodic in character, flowing sporadically and rapidly during the periodic intense rain showers. The abundance of water sets Caprivi apart from the rest of the country. Of only five permanently flowing rivers in Namibia, three are in the Caprivi: the Choobe, Kwando and Zambezi. The main hydrological feature of Kavango Region is the Okavango River. The Cuito River, a tributary, joins the Kavango River from Angola at Dirico, so flow volumes are greater downstream of this point. Apart from this difference, hydrological features of the upstream section are similar, but not identical, to the aforementioned description. One important deference is the timing of flooding and the contribution of each tributary. The Okavango River at Rundu experiences its highest water from January to May, with the peak in April, in response to summer rain falling in the upstream catchment and making its way
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Northern Regions. Flood Risk Management Plan 2011 downstream. Water in the Cuito is delayed by a longer period and peaks in about May, with a smaller peak. The Okavango brings in much more water during floods and then its level drops for the months of June to November. The Cuito peak is relatively much less than the Okavango, but this river contributes more to the downstream flow during the months of June to November. The omuramba that enters the valley of the Okavango River holds water for short period, up to about 4 months depending on the summer rains, and water might even flow for short distances in them, but otherwise they are not active rivers at all. The most important hydrological system in the rest of the northern region, the endorreic drainage to Etosha Pan, comes from Cuvelai basin from Angola, it is responsible of the extremely floods in these entire regions also with heavy rain fall average. Groundwater: With the exception of the Namib Desert, ground water occurs in varying quantities over almost the entire region. In some areas artesian springs occur, while pans and sand deposits along several river courses serve as ideal reservoirs for usable water. In certain areas the withdrawal of groundwater is controlled in order to prevent over-exploitation and a further lowering of the groundwater table. Often the groundwater is virtually unusable owing to the presence of dissolved solids derived from the rocks in which the water is stored. Specific concentrations of fluorides, nitrates and sulphates further affect the usability of the water. Using the World Health Organization’s criterion for general human consumption of 200- mg/litre concentrations of TDS (total dissolved solids) as a guideline it is clear that most of the subterranean water resources are indeed usable. Climate: Rainfall (Annual average): Average rainfall in the northern regions its between 300 – 871 mm from Omusati to Caprivi. Frequency of rainfall (annual average number of days with rain). 30 To more than 60 days.. Rainfall variability: -Average deviation as % of annual average: Less than 20-50 %. Seasonal distribution of rainfall. Rainfall for October to March as % of annual average: 80-90 %.
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Length of rain season: Number of months per year with more than 50 mm. of rain. From 2 until more than 5 months Since the start of 2009, the northern regions, particularly those traversed by the Cuvelai basins which are Omusati, Ohangwena, Oshana and Oshikoto have experienced incessant torrential rains and high water flows arising from Angola causing severe flooding. In Kavango and Caprivi, flooding has been caused by torrential rainfall and flooding of the Choobe, Zambezi, and Kavango rivers.
Climate Regions: Main Type: Steppe. Dry regions with a deficiency in rainfall, steppe or semi-desert, annual mean temperature above 18 Degree Celsius, month with a maximum in the early summer, rainfall during summer. Occurs in a wide belt in the north to the northeast of the country including all the regions of the north until Caprivi region.
Natural Vegetation: Woodlands: Forest Savanna and Woodlands: Occurs in the north and northeast part of the country, along the border with Angola, Zambia and Botswana, including Ohangwena, Kavango, and Caprivi Region. Savanna: Mopane Savanna (Oshana and Omusati regions).
Physical Geographical Landscapes: Plains are the predominant landscapes in the northern regions, except in the southwest part of Omusati region, where it is possible to find plains with scattered hills.
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Quantitative Assessment of Environmental Impact The intensity of values of impacts (IN) should be calculated by the following formula: IN = + - (3 I M + 3 D E + D E +MO + P E + R V + RC + E F + S S A + PR) Where:
Recuperation (RC). (By means of human activity) Nature of impact: ! Recuperation immediately 1 ! Good Impact + ! Recuperation in medium term 2 ! Harmful impact - ! Mitigation 4 Destruction or recuperation of factor (D E) Effect (EP) ! Low 1 ! Indirect (Secondary) 1 ! Medium 2 ! Direct 2 ! High 4 ! Total 8 Moment (MO) Increment (SSA) ! Long term ! Simple 1 ! Medium term ! Accumulative 2 ! Immediately ! Synergic 4 Persistence (PE) Periodic (PR) ! Ephemeral 1 ! Irregularity or discontinuous 1. ! Temporal 2 ! Periodic 2. ! Permanent 4 ! Continuous 4. Reverse (RV) Importance of factor (IM) ! Long term 1 ! Irrelevant 1 ! Medium term 2 ! Relevant 2-4 ! Irreversible 4 ! Protected 12 ! Irrecoverable 8 Intensity values (IN) lower than 20, show that the effects are irrelevant or compatibles with the environment. Values between 21 y 40 shows that the effects are moderated, between 41 y 60 it will be severe effects, and > 60 the effects will be critics. Red flags: Should be allocated red flags in those effects more relevant and critics, and where the implementation of corrective measures is impossible. It’s necessary to give to each factor an environmental weight expressed as ‘Units of Importance” (UIP) as result of relative distribution of 1 000 assigned to the total of environmental factors (Environment of Optimal Quality). Weighting Indexes Total Inert Total Perceptual 380 100 Environment Environment Edaphology 50 Landscape 100 Total Biotic Underground water 60 160 Surface water 60 environment Odors 40 Vegetation 80 Noises 40 Fauna 80 Gases 40 Socio-economic 360 Dust 40 environment Infrastructures 90 Land uses 70 Economy 200 Total Environment 1 000 UIP
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3.2.1- Graphic Examples of the Main Environmental Impacts
Dumping sites located in flood prone areas
Insufficient bridges and culverts in roads
Construction of water and sewerage networks in flood prone areas Buildings located in natural water ways
Unprotected water canal affected by flood waters Informal settlements located in flood prone areas
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Northern Regions. Flood Risk Management Plan 2011
Poor insertion of green areas in new developments Poor maintenance of existing drainage systems
Lack of tarred roads in urban areas
High erosion process due to insufficient storm water infrastructure
New roads as dykes, obstacles for free water flows Sewerage network over flooded
Erosion due to sand extraction near riverbanks Shallow oshanas and drainage channels
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Northern Regions. Flood Risk Management Plan 2011
3.3- Situation Analysis
3.3.1 – Main Natural Hazards The main hazards affecting the studied northern regions are:
! Floods due to the overflow of Zambezi and Kwando rivers with their main hydrological basins in Zambia and Angola territories and Cuito and Kavango rivers, which hydrological basins are totally in Angolan territory. In the first case the main impact occurs on Caprivi Region and in the second one in Kavango Region. In both cases, the fluvial systems contain appreciable water volumes permanently, which increases during rain seasons.
! Floods that occur in the Cuvelai basin, hydrographic system made of an important number of oshanas that evacuate the water resulting of the rainfall in the basin, which mostly is located in Angola, but with a very important presence in Oshana, Omusati and Ohangwena regions.
! Heavy rains that occur in a short period of time in all the visited regions.
3.3.2- Vulnerability The vulnerability related to these natural hazards increases due to several factors, such as:
! Presence of disperse population and human settlements in flood prone areas associated to the rivers mentioned above and to the Cuvelai basin.
! Modification of the natural environment through the construction of new roads without proper environmental impact assessments to protect them and to preserve water courses through natural ways, building the necessary facilities, such as culverts and bridges with the required dimensions. There is a major road rehabilitation process in place, which incorporates the improvement of these elements, but still without the proper requirements.
! Existence of informal settlements in the main urban centers located in the water natural ways, blocking the water courses.
! Insufficient maintenance of the storm water systems (natural or man-made), with the presence of obstacles in culverts and channels.
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! Lack of proper Master Plans in the urban centers that consider storm water systems solutions and land use regulation.
! Poverty status of an important population segment.
! Fragility of building materials used for the construction of houses in rural areas.
! Irregular land use process.
! Lack of risk’s perception.
! Traditions, way of life of local population.
3.3.3- Coping Ability There is a well prepared system in all levels (national, regional and local) to cope with the flood events during and after the disaster occurrences (relocation camps, coordinated work among different actors, contingency plans, etc.). Although there is a good work addressed to mitigate vulnerability, still it is not enough, so it is important to increase the efforts in the preparedness phase, especially related with the preparation of threat studies, vulnerability evaluation and risk analysis. To accomplish these purposes is a priority to develop regional and urban integrated studies, establish urban and territorial regulations for the land use and the implementation of policies in order to relocate permanently population living in high risk areas to safer lands.
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CAPRIVI REGION FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 33 Northern Regions. Flood Risk Management Plan 2011
4.0- SITUATION ANALYSIS PER REGIONS
4.1- CAPRIVI REGION
4.1.1- Regional Context
4.1.1.1- General Characterization Location: Caprivi is the north-easternmost region of Namibia. It has high potential for manufacturing development, especially for outward looking investors. To the north, it borders Angola and Zambia, to the east, Zimbabwe, with Botswana lying to the south and south east. It has the highest rainfall of all regions in Namibia with a mean range of 600 mm in the west to 700 mm in the north-east. There are eight perennial rivers in the region with the Chobe, Zambezi and Kavango being the largest. The region has five conservation areas and is a popular tourist destination with plenty of scope for development in this field. The Trans-Caprivi highway linking the region with Botswana and Zimbabwe runs the length of the region, and is in constant use by heavy transport vehicles. There is no railway link, but the airport at Mpacha is large enough for jets to land. Physical features: All the region is between 1000-1 500 m. of altitude, except the most eastern part of the region with 500-1 000 meters above sea level. The most predominant geological formation in this region is Sandstone and calcrete from period tertiary to quaternary-cretaceous. The abundance of water is a distinctive feature that differences the Caprivi region from the rest of the country. Of only five permanently flowing rivers in Namibia, three are in the Caprivi: the Chobe, Kwando and Zambezi (Mendelsohn and Roberts 1997). Water quality is highly variable throughout the region. The chemical composition of water rather than the yield potential is restricting the use of groundwater. It is frequently too salty, is unpalatable or emanates from dirty wells and backwater. Good quality water is generally found within 5-20 Km. from the rivers which recharge the aquifers. Recharge in the central parts of the region is low. Vegetation: Many areas of dense woodlands in Caprivi have been converted to open grassland and shrublands as a result of frequently fires. While fires have important benefits for plant communities, their increased frequency causes damage to vegetation. As a result, large areas of the region are now bush-encroached, leaving little space for grass growth (Mendelsohn and Roberts 1997). Climate: Average rainfall in Caprivi ranges between 348mm- 871mm. per year, and increase gradually from south to north. This represents a high rainfall in Namibian terms.
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The frequency of rainfall is more than 60 days as annual average, with a rainfall variability of less than 20-25 %. The 80-90 % of annual average of rainfall occurs from October to March, with more than five months per year with more than 50 mm of rain. Size of the Region: The region covers a total area of 14 528 km2 and accounts for 1.8 per cent of the total land area of Namibia. Population: The region is populated by 79 826 inhabitants (4.4 % of Namibia’s total population), with a density of 5.5 people per km2. Households: The population resides in 16 839 households, with an average size of 4.7 people per household. Administrative structure: The region is divided into 6 constituencies (Kabe, Katima Mulilo Rural, Katima Mulilo Urban, Kongola, Linyanti and Sibinda). The administrative centre of the Region is Katima Mulilo, which is also the seat of the Regional Council and government ministries. Settlement patterns: 72 per cent of the population in Caprivi region lives in rural areas. The human settlement system is classified as follows: Towns: 1 (Katima Mulilo) Settlement areas: 5 (Bukalo, Goma, Sibinda, Kongola, Sangwali) The rest of the region’s population resides in a scattered way in rural areas (homesteads, isolated houses, etc.).
Constituencies in Caprivi Region
Population and households’ distribution per Constituencies (Source: 2001 Census) Constituency Population Households Average size Kabe 14 962 2 924 5.1 Katima Mulilo Rural 14 566 2 999 4.8 Katima Mulilo Urban 22 704 4 947 4.5 Kongola 4 419 851 4.8 Linyanti 13 985 3 108 4.5 Sibinda 9 190 2 010 4.6 Total 79 826 16 839 4.7
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4.1.1.2- Situation Analysis A large portion of the territory of Kabbe constituency is extremely low, so is a huge flood prone area. Flooding is not an unusual event for this part of the country, but the problem is worsened year after year. The increase of population settled in the flood plains is one of the main reasons of the high number of people affected by the disaster. On the other hand, some parts of the territory (considering Kabbe and Katima Mulilo Rural constituencies) are not directly affected by flooding including some settlements located in adjacent areas, such as Bukalo, Kabbe, Lusese and Schuckmansburg, with different characteristics: Bukalo: located in Katima Rural constituency has a good accessibility through a tarred road from Katima Mulilo and through a gravel road to Kabbe. The area has been proposed to be upgraded in one first stage within a regional strategy. At the present time there are some social facilities that should be increased in order to motivate a gradual relocation process by people living in vulnerable areas. Bukalo Kabbe: It constitutes the main administrative center of the constituency. The present population is about 3000 inhabitants. The area has some social facilities such as school, clinic, literacy center, constituency office, community court, agricultural center and shops. Good accessibility through a gravel road from Bukalo. Similar conditions are present in Lusese. Kabbe Shuckmansburg: It is a privileged area inside a very high flood prone area in Kabbe constituency. There are some facilities such as school, clinic, police station, shop. A relocation camp is set almost permanently in the zone for displaced population from Namiyundu, Nankuntwe and other nearby Schuckmansburg relocation camp. areas. The accessibility is the main constraint of the area. A recent project will allow access to and from Katima Mulilo and other areas through a ferry. In the year 2009, the floor disaster affected 26 263 persons in the Caprivi Region (30.2 % of the total population), which were displaced from their homes, mostly from the Kabbe constituency. The region had the highest volume of persons in relocation camps (19 738) among the six most affected regions, which represents 68.2 %. Thirty relocation camps were established in the region to temporarily accommodate the displaced families.
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The most affected area was Kabbe constituency, where more than 90% of the territory was flooded and many villages were submerged, with the displacement of the majority of the about 15000 inhabitants of the area to thirty relocation camps, where some of them stayed for a period of six months and more. Other affected areas were the flood plains along the Kwando, Linyanti and Chobe rivers, which affected mostly central areas of Kongola constituency, western and southern areas of Linyanti constituency, as well as southern areas of Sibinda and Katima Mulilo Rural constituencies. While in Kabbe the major impacts were in the local population, in these areas the most affected territories were occupied by crop lands and protected areas, with influence also in the tourism industry. In the year 2011, a total of 2 791 households and 12 361 people were affected, excluding those self relocated to higher ground. In the education sector, 22 schools and 4 595 learners were affected, six of the schools had to be relocated. In the Health sector, 10 clinics were affected, while 4 were isolated. There were reports of some cases of Diarrhea, Malaria, Skin infections and malnourished children. Agricultural sector was severely damaged with 1 655 hectares of crop fields totally destroyed and a total of 793 affected farmers. A total of 25 temporary relocation camps were set by the Regional Government totaling 12 361 people from the flood affected communities and low lying areas. Even when all basic needs were not totally covered, an important number of logistic resources including food were provided by the government and other institutions to the affected people. Detailed analysis per relocation camps and other affected areas (2011): Kabbe relocation camp
Kabbe relocation camp (26-4-2011) There were 940 people from Muzii settlement (110 km distant) actually relocated in these temporary facilities, which has been used for these purposes since 2004, on a total of 210 tents including the school on 12 military tents (308 learners from 1st to 10th grade). It’s served with water from a well pumped to raised tanks and a system of taps and one sanitary latrine. There is no electricity provided for the camp. Main problems found: Being a permanent relocation camp there is a lack of needed infrastructure to cover basic people’s need, i.e. non functioning water supply system (no pump), not enough sanitary facilities and no systematic maintenance of the existing one (apart that it represents a hazard to the safety of underground water), no electricity, no basic medical attention (nearest medical facility 2km distant) Recommendations ! Re-organizing of the camp internal distribution. ! Creation of minimal infrastructural conditions (electricity, water supply, drainage, sanitation, communal kitchen facilities, etc.)
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! Provision of basic medical assistance. ! There is a need of a sociological study in order to know the people’s ideas with regards to probable definitive solutions. ! As the flood problems solution goes beyond particular or specific places issues, there is a need of a wider and integral study to determine the feasible hydraulic works to be proposed as well as definitive relocations decisions, job creation, land use, etc. Lusese relocation camps (A, B, C) According to the preliminary flood report for the Caprivi region there is a total of 840 people from Itomba, Impalila island and Nsundwa relocated in the three camps and in each of them the same problems of Kabbe’s can be found even when not all of the three were actually site visited. Same recommendations as for Kabbe relocation camp. Ngoma settlement area The water level from the Chobe river are very increased in the surroundings of Ngoma with some of its road and electrical infrastructure under water, also the road access to the east extreme of the region are cut off. Recommendations ! The safety standards for the aerial and/or underground electrical nets affected should be checked. Bukalo settlement area
Bukalo settlement (26-4-2011) Bukalo is a small but consolidated settlement served with technical infrastructure and an already started to build extension, there are no physical structures affected in the settlement but about 90 traditional houses are isolated from the rest of the town by a flooded low lying area of around 200m wide Recommendations ! To relocate, if possible, the isolated traditional community to a high ground linked to the settlement, or ! To build an up-leveled gravel road connecting both sides
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Schuckmansburg settlement area and relocation camp:
Shuckmansburg settlement and relocation camp (27-4-2011) This settlement is located by the Zambezi river linked to Katima Mulilo by a single rustic access road 70km distant, 6km of which are currently under water, about 2m depth therefore the whole settlement is totally isolated. In the relocation camp there are people from other threee affected settlements (Namkuntue, Namiundo and Sundua) who remain there for as long as the floods don’t allow them to go back –6 months time- According to information provided in the site (police officer and the camp manager) there are about 5 000 people gathered here on 608 traditional houses and tents. (1484 people from Schuckmansburg, 990 from Namkuntue, 720 from Namiundo and 65 from Sundua). Water is supplied from wells of non-drinkable salty water, pumps, raised tanks and a system of taps (people use water from the river), a number of latrines well disposed, electricity only for the clinic and the teachers houses, so 95% of the settlement is without electricity. There are some social services like a medical clinic about to be finished, the local school and the provisional schools from the relocated settlemnts, in tents. Foods for the inhabitants has to be provided by the government and is kept in tents facilities that does not offers proper safety and security. Main problems found: - Inexistence of a proper road for accesing the settlement - The camp does not have a proper internal distribution so it is confused and overcrowded - No safe water provision, lack of maintenance to the sanitary facilities, no public lighting provision… - Unapropiated food storage facilities Recommendations: - Re-organizing of the camp internal distribution - To build a proper access road to Schuckmansburg settlement (this will need a previous topographic study and a engineering project) - Improvement of the water supply and sanitation systems - To provide if possible electricity to all relocated people, or at least public lights. - To improve the food storage facilities, taking into consideration that this will be a recurrent situation - An integral study should be carried out, including the sociological aspects, in order to find appropriated solutions for the four affected communities, that might as well include its permanent relocation
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 39
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Muzii settlement
Muzii settlement (27-4-2011)
This is a small settlement practically covered by water except for the school and a number of close houses, all of its inhabitants are relocated to the Kabbe relocation camp and only 6 people were left behind to take care of the belongings saved at the school that is not affected. All access roads to Muzii are cut off and all the surrounding crop and grazing fields are as well under water. According to some of the interviewed inhabitants part of them are very interested in keep living by their lands and means of life –crop fields, livestock- while others are willing to be permanently relocated. Main problems found: The isolation of the settlement in times of flood as well as the loss of their goods is the main concern for Muzii’s people. It becomes a real hazardous thing to be stranded there with lots of wild water animals like snakes and crocodriles around. Recommendations: Again the need of a sociological study that takes into account the ideas, interests and desires of the local people, along with a wider hydrological assessment in order to find if there is the possibility to decrease at least in a minimal grade the level to be reached by flood waters. Definitive or even temporary relocation to a neighboring higher place could be an alternative solution The settlements of Nmkuntue, Namiundo and Sundua are totally under water being impossible to reach but in the same way its definitive or at least temporary relocation should be taken into consideration, otherwise, the feasibility of engineering works to improve and up-level its access roads should be carried out. Katima Mulilo’s Mambueza-Ngweza drainage canals system
Mambueza-Ngweza canal system (28-4-2011)
By the town river bank there is low lying flooded or flood prone areas where some obstructed water courses had been worsening the situation. The town master plan foresees the construction of a system of drainage canals and even some of the works have been already projected and/or started to build.
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Main problems found: - Obstruction and lack of maintenance of the existing canals or watercourses - Probable indefinitions of the proposed projects for the drainage canals system Recommendations: - To recover the functioning capacity of the existing watercourses by means of its appropriate rectification and to warranty its systematic maintenance. - To review both the Master plan dispositions (bringing into consideration the impacts of the last years flood events) and the already approved projects for the drainage systems and related works.
RISK MAP FOR CAPRIVI REGION High Risk Zones Sub-zone 1 (Eastern and southern parts of Kabbe constituency): Constitutes one of the highest flood prone areas of the whole country. The occurrence of flood events is almost a permanent concern, affecting almost the constituency’s total population (about 15000 inhabitants). The risk is very high and solutions to avoid it are almost impossible. Sub-zone 2 (Along the flood plains of the Kwando, Linyanti and Chove rivers, affecting Kongola, Linyanti, Sibinda and katima Mulilo Rural constituencies). Sub-zone 3 (Katima Mulilo Urban). Moderate Risk Zone (Western strip of Kabbe constituency and Katima Mulilo Rural constituency). Low Risk Zone (Rest of the region).
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KATIMA MULILO TOWN FLOOD RISK MANAGEMENT PLAN
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 42 Northern Regions. Flood Risk Management Plan 2011
4.1.2 – Katima Mulilo Town
4.1.2.1-General Characterization The town is between 900 – 1000 meters of altitude, except the most eastern part of the region with 500-1 000 m. above sea level. Katima Mulilo’s physical environment is characterized by its flat topography, the presence of the Zambezi River in its northern border and vast area of floodplains which form its unique for flora and fauna. During the 2001 Housing and Population Census, Katima Mulilo Town represented by the Katima Mulilo urban constituency (which concedes with municipality boundaries) recorded a total population of 22 704 residents, out of which 10 540 were male and 12 164 were female. Considering an average growth rate of 1.8 %, the number of population is approximately 32 026 in 2011. Katima Mulilo is the only proclaimed town in the region with a high supply of jobs in non- traditional and agricultural occupation. This comprises jobs in the production sector (MEATCO, Nam-Mill and Namibian Breweries) and civil servant in the service sector. But the numbers of job-seekers exceed the number of job opportunities. Many people make their living through the informal sector. Despite being an agricultural area, there are no agricultural industries. Agriculture is practiced widely on a small scale region wide. The only industries claimed by the sector are the abattoir and milling companies. The road network is not in good condition, with almost 95 % still unpaved (gravel road). Town boundaries Katima Mulilo is urbanized mostly in the eastern part of the proclaimed townlands, which are bounded on the north side by the Zambezi River, and in the northwestern side by the Namibia – Zambia border. Most of the land in the western side is vacant or occupied by agricultural developments. The residential area of Mahohoma, located on the east, is the only suburban area of the existing township area. Use and occupation of the land. There is prevalence of vacant land within the town proclaimed lands. The other main land uses are residential, mostly in informal and/or recently formalized settlements, social services, industrial and agricultural.
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Northern Regions. Flood Risk Management Plan 2011
Informal settlements:
Butterfly Informal Settlement. The Butterfly community is found directly east of the main road (B1) leading to Katima Mulilo. It is firstly identified through the presence of the High Radio Tower located in the middle of Butterfly on a triangular portion of land which had been fenced off accordingly. Evidently, the site has been developed extensively and with the exception of a small number of erven, all have been developed through formal and permanent dwelling units. Butterfly accommodates an estimated 600 residents excluding those living as part of the Shack Dwellers Federation. With the exception of 4 sites, all erven are used for residential purposes. Two churches and one local business were recorded. There is a low level of utility services. Water is found in the form of randomly installed pre-paid stand pipes. No other services exist. Topography is relatively flat, but only three erven are located below the 940m contour line. The Shack Dwellers’ structures could very well be at risk of flooding. Formalization Proposal A total of 182 residential erven were formalized, which are almost all equal in size with an average erf size of 638 m2. The site currently accommodating the Shack Dwellers is formalized as a general residential erf to take into account the large number of people living on the site. In total, 3 Local business erven are provide with an average size of 1947 m2, one formalized on its current location and other two, located to the southern entrance of Butterfly, to accommodate a general dealer for basic necessities and an open market. Three institutional sites were formalized. Two of these are already being used by churches while a third one is planned to accommodate future purposes such as a clinic or kindergarten. At the same time, one local authority erf was provided.
Choto Informal Settlement Choto consists of long rows of detached dwellings, most of which can be classified as temporary or traditional structures. The site has been subjected to extensive development and it is now in a process of formalization. Infrastructure: - Overhead power lines provide electricity at random both dwelling houses and business buildings. - Communal water points (pre paid communal standpipes). - No formal sewer connections (existing households make use of either dry pit latrines or in some instances the bush). In the Choto area there are some areas prone to flooding. In early 2008, Choto suffered heavy floods, due to some structures had been built below what is believed to be the flood line and the lack of a proper storm water system, not only in the area, but in the whole town. Formalization Proposal The areas prone to flooding were planned as public open spaces and development should not be allowed on these areas.
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Northern Regions. Flood Risk Management Plan 2011
A total of 307 single residential erven were planned. Choto Proper has 136 residential erven and Choto Extension 1 has 171 residential erven. Erven vary in size between 300 m2 and 1645 m2 with an average erf size of 577 m2 in Choto Proper and 527 m2 in Choto extension 1. In total 49-bussiness erven are provided, most of them located along the 14 m road collector passing through Choto for existing businesses. Based on local experience and planning standards in Namibia, residential land in a neighborhood comprises about 50 % to 60 % of the total area, while the remaining land is required for traffic circulation, institutional purposes, open spaces, supporting land uses and commercial land. In this proposal it is evident that less residential land could be provided as a result of the large are prone to flooding which had been formalized as open public spaces. Three institutional sites were planned: Kinder garden (existing), School (existing) and a large site for future institutional uses.
Mahohoma Informal Settlement Mahohoma is an outlying residential area situated on the Katima Mulilo Townlands. The settlement area is located north-east of Katima Mulilo, directly adjacent to, and south of the Ngoma-Katima Mulilo section of the Trans-Caprivi Highway. The dominant land use in Mahohoma is residential with only one business alongside the traffic collector leading through the settlement. One church is present within the area with a general under provision of other social services such as schools, medical facilities, recreational activities, etc. Electricity infrastructure is available in the site, while the water supply is through standpipes. There is no sewer. The topography of Mahohoma and its environs is characterized by a flat plain which renders it suitable for the proposed upgrading project. To the east (directly adjacent to and forming part of the elephant’s nest) and to the west, directly adjacent to the junction with the Main Road, areas of depressions are identified from the 1 meter contour intervals. These areas are flood prone and had been accommodated as Public Open Spaces in the proposed layout. The area is characterized by dense growth of large trees, which required the enlargement of the erven proposed to thereby allow sufficient erf sizes to accommodate both the large trees and houses. Formalization Proposal Access into Mahohoma is obtained via the main road leading to Ngoma Border Post along the Trans Caprivi Highway. The area is located on the North Eastern periphery of the town of Katima Mulilo, south of the main road. The objective was to ensure a road network, which would allow efficient, effective and functional traffic circulation inside the proposed new township without compromising the mobility of traffic on the main road. At the same time, it was considered very important that the hierarchy of roads would enable functions of mobility as well as accessibility within the new township. Although not part of this layout an arterial road link was provided for under the first phase of the Mahohoma project. This arterial road will provide an alternative road link between Mahohoma and the rest of Katima Mulilo. It is not foreseen that this road will be built over a short term, but is in the interest of the overall development of town to plan and facilitate a functional road hierarchy. Traffic collectors were provided to allow traffic to move through the new extension and link with the previous extension done during phase 1 of this project. The collectors gain access directly from the main road leading to Ngoma at two new access points. These collectors are 16 m wide.
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The lowest order roads are referred to as local access roads. These roads are 10 m wide and provide access over short distances to mostly residential properties. A total of 151 single residential erven were planned. The average residential erf size is 479 m2. A commercial node was planned as part of phase 1 of the project, located in the centre of the two residential areas, so both can use this small and central development node. One existing business was formalized as Local Business Erf and one Hospitality site was planned at the entrance to the township. Based on local experience and planning standards in Namibia, residential land in a neighborhood comprises about 50 % to 60 % of the total area, while the remaining land is required for traffic circulation, institutional purposes, open spaces, supporting land uses and commercial land. The presence of large areas which are prone to flooding has resulted in this ratio of residential land being slightly lower than normal (37 %). Three institutional sites were planned, one for the existing church, one additional and vacant erf for a Community Hall and the last one for a Kindergarten in close proximity to the existing school sites. In addition to the institutional sites above, one erf was planned and is earmarked for Local Authority purposes. The occurrence of flooding has resulted in some areas being formalized and planned as dedicated Public Open Spaces. These sites should not be developed and existing residents within these flood prone areas should be informed about the status of the land.
New Cowboy Informal Settlement New Cowboy is an informal residential area, located approximately 3 km south of Katima Mulilo CBD and approximately 400 m east of the main road. It is estimated that the whole New Cowboy accommodates about 6000 people. Over the years, New Cowboy has grown in size and the density increased dramatically. The current land uses are mainly residential with a number of businesses and an under-provision of social services (e.g. schools, recreational activities, etc.). Only one church and one clinic were recorded. The area is served by electricity, while formal communal water connections exist in the form of pre- paid communal taps. No sewer connections exist. Topography is flat. Two areas of depression were identified as possible flood areas and were indicated as Public Open Spaces Formalization Proposal 703 residential erven were planned, with an average erf size of 400 m2 For Commercial Purposes, 12 General Business erven are provided with an average size of 786 m2. For Neighborhood Purposes, two institutional sites were formalized for the purpose of a church and a clinic.
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Social services: Katima Mulilo is well served by social services. There is one hospital with 200 beds, one health center and three public and private clinics. In the education sector, there are six primary schools, three combined schools and three secondary schools, while in the field of further education, the town is seat of the Zambezi Vocational Training Center, the Caprivi College of Education, as well one branch of the University and Polytechnic of Namibia.
Technical services Water Supply: The main source of water supply is the Zambezi River, with a system including a water intake pump, a purification plant (NAMWATER) and a reticulated network through the existing roads using PVC pipes, serving the whole urban area. Informal settlements are served through water towers and communal taps with a prepaid system.
Drainage: There is not a complete system, only partial solutions in some areas. A Storm Water Master Plan for the town was prepared, but it has not been implemented. Sewerage: The system in place is very old, with more than 50 years of functioning, so it is facing many functional problems (periodical obstructions, overcharges, etc.). There are 20 pump stations and oxidation ponds located in the west part are over their life spam. During heavy rains, the sewerage network is seriously affected, so a new system of oxidation ponds is developed in the east side, incorporating the settlements of Choto and Butterfly. The informal settlements are not connected to the existing sewerage network, while the industrial area is served through septic tanks. The town is fully served by communications and electricity.
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4.1.2.2.Situation Analysis Katima Mulilo is the only substantial urban centre in the Caprivi Region. The Zambezi river periodical overflows affect the northern areas of the town, where there are several buildings and one residential area (Boma), although it doesn’t constitute a major threat to most of the town area. The main reason of flooding in the urban areas is an increase in surface runoff during rainfall periods combined with the presence of low lying areas within town borders. This situation is aggravated by the lack of a storm water drainage system and the presence of buildings and informal settlements that interfered with the water natural ways. In some parts of Katima Mulilo the infrastructure and housing have been built below the flood line. Current maintenance regimes are inadequate, resulting in the blockage of culverts, sewers and other drainage channels. The most serious situation is presented in the informal settlement of Choto, located on the southern part of Katima, with a population of 4000 inhabitants. The only technical evaluation of flood levels in the town of Katima Mulilo was done in 1987 by the department of Water affairs – which was then a government department. This evaluation was reported on in an old Structure Plan for the town which was prepared in 1988 by the Division of Development Planning of the then South West Africa. An extract from the report is as follows: “Katima Mulilo is situated on the banks of the Zambezi River. Large areas adjacent to the banks become flooded owing to seasonal changes in the water-level of the river and the relative evenness of the topography. During the rainy season, the lower-lying molapos are usually filled by rainwater which dries up by the end of the winter. These molapos lie in a half-moon around the town, hampering further (eastward) urban development. In an investigation conducted along the river banks, the Department of Water Affairs established the 1-in-50-year flood-mark to be at contour level 941m, and the 1-in-100-year mark at 942m (letter 11/6/3/1/2 dated 19 May 1987 from the Department of Water Affairs). The existing town generally lies higher that the 940m contour level. There is, thus, no danger of flooding any future urban development, according to the consulting engineers, provided that such development takes place on ground higher than the 940m contour level. If the 941m and 942m contour levels were to be used as the limiting flood-marks, then very little ground would remain for future urban development. Moreover, a large number of existing structures would then be classified as being within the flood area. The conclusion reached, therefore, was that the 941m flood-mark along the river bank should be taken into account if any permanent structures were to be built, whilst the 940m contour level would apply to development in the town”.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 48
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 49
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 50
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 51
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 52
Northern Regions. Flood Risk Management Plan 2011
KAVANGO REGION FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 53 Northern Regions. Flood Risk Management Plan 2011
4.2- KAVANGO REGION
4.2.1- Regional Context
4.2.1.1- General Characterization Location: Kavango is one of the thirteen regions of Namibia. On account of its rather higher rainfall than most other parts of Namibia, this region has definite agricultural potential for the cultivation of a variety of crops. There is also potential for organized forestry and agro-forestry, which should stimulate furniture making and related industries. In the north, Kavango borders the Cuando Cubango province of Angola, and in the southeast it borders, and in the southeast it borders the North-West District of Botswana. Domestically, it borders the following regions: Caprivi (east), Otjozondjupa (south), Oshikoto (west) and Ohangwena (northwest). The perennial Okavango River on its northern border provides many different resources for residents, including water and food, and construction and craft materials. Divided into nine constituencies, the region accounts for 5.9 % of the total land area of Namibia and contains 11 % of its population (202 691 inhabitants). The size of the region is 48 463 Km2 (5.9 % of Namibia’s area).The annual population growth rate has been calculated at 3.7 %, which is 1.1 % higher than the national average. Rundu is the administrative capital of the Kavango Region. Physical features: The main hydrological feature of Kavango Region is the Okavango River. The Cuito River, a tributary, joins the Kavango River from Angola at Dirico, so flow volumes are greater downstream of this point. Apart from this difference, hydrological features of the upstream section are similar, but not identical, to the aforementioned description. One important difference is the timing of flooding and the contribution of each tributary (Mendelson and el Obeid 2003). The Okavango River at Rundu experiences its highest water from January to May, with the peak in April, in response to summer rain falling in the upstream catchment and making its way downstream. Water in the Cuito is delayed by a longer period and peaks in about May, with a smaller peak. The Okavango brings in much more water during floods and then its level drops for the months of June to November. The Cuito peak is relatively much less than the Okavango, but this river contributes more to the downstream flow during flow during the months of June to November. The Omarumba that enter the valley of the Okavango River hold water for short period, up to about 4 months depending on the summer rains, and water might even flow for short distances in them, but otherwise they are not active rivers at all.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 54
Northern Regions. Flood Risk Management Plan 2011
Vegetation: Kalahari woodlands are widespread in Kavango Region, and, in places where there are dunes, woodlands alternate with thin strips of grassland representing the lowest levels of the interdune valleys (Mendelson and Obeid 2003). The Kalahari woodlands are variable from place to place in their species composition and community structure, some places being quite open, others densely wooded with tall trees and little understory, others having mostly medium-sized trees and lots of undergrowth. These variations are small-scale and not significant to the environmental assessment. The dominant trees that occurs in this woodland (not in order of predominance) are Kiaat (Pterocarpus angolensis), teak (Baikiaea plurijuga), syringa (Burkea africana), silver terminalia (Terminalia sericea), mangetti (Schinziophton rautanenii), false mopane (Guibourtia colesperma), cmelthorn (Acacia erioloba), marula (Selecocarya birrea), and weeping wattle (Peltophorum africanum). In places there are small stands of makalani palms (Hyphaene petersiana). Riverine forest is now mostly destroyed along the entire Namibian section of the Okavango River. However, where human claring is prevented such as at lodges and tourist establishment, natural forest is return. This comprises trees such as Knobthorn (Acacia nigrescens), camelthorn (Acacia erioloba), syacamore fig (Ficus sycamorus), sausage tree (Kigelia africana), appelblaar (Lonchocarpus capassa) and jackal berry (Diosyros mespiliformis). Grass grows between trees and shrubs in the woodlands, and certain types of tall strong grasses (mainly Eragrostis pallens) are harvested for tatching. Omiramba support good grazing fodder for livestock, particularly the lawn grass Cynodon dactylon. Swamps and floodplains alongside the Okanvango River host reeds, sedges and grasses depending on their degree of saturation and how frequently they are inundated. Reeds growing in areas that are regularly (annually) flooded and on the margins of permenent water are an important resource used by local people. Climate: The average rainfall in Kavango ranges between 400 mm- 600 mm. per year, and increase gradually from south to north. No rain of any significance falls from May to September, and the chance of rain increases progressively from October until January, the month with the highest total on average, and then decreases again until April. 80 % of the rain falls between December and March. The frequency of rainfall is more than 60 days with rain, with a rainfall variability of less than 20 – 30 % of average deviation of annual average. The seasonal distribution of rainfall is 80 – 90 % from October to March. The length of the rainy season is between 4 to 5 months with more than 50 mm of rain. Size of the Region: The region covers a total area of 48 463 km2 (5.9 % of the total land area of Namibia) Population: The region is characterized by an extremely uneven population distribution. The interior is very sparsely inhabited, while the northernmost strip, especially along the Kavango River, has a high population concentration. Largest urban settlements are the capital Rundu and the towns of Nkurenkuru and Divundu. The region is populated by 202 694 inhabitants (11.0 % of Namibia’s total population), with a density of 4.2 people per km2.
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Households: The population resides in 30 467 households, with an average size of 6.5 people per household. Administrative structure: The region is subdivided into nine electoral constituencies: Mpungu, Kahenge, Kapako, Rundu Rural West, Rundu Urban, Rundu Rural East, Mashare, Ndiyoma and Mukwe. The administrative capital of the region is the town of Rundu.
Settlement patterns: The vast majority of the population (82 %) in Kavango region lives in rural areas. The human settlement system is classified as follows: Towns: 2 (Rundu, Nkurenkuru) Settlement areas: 2 (Divundu, Ndiyona) The rest of the region’s population resides in a scattered way in rural areas (homesteads, isolated houses, etc.). Population and households’ distribution per Constituencies (Source: 2001 Census) Constituency Population Households Average size Kahenge 30 903 4 515 6.8 Kapako 26 263 3 954 6.6 Mashare 16 007 2 289 6.9 Mpunge 18 660 2 499 7.4 Mukwe 27 250 4 189 6.3 Ndyoma 19 565 2 978 6.4 Rundu Rural East 18 250 2 733 6.7 Rundu Rural West 26 623 4 093 6.3 Rundu Urban 19 173 3 217 5.8 Total 202 694 30 467 6.5
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4.2.1.2- Situation Analysis The northern part of the Region is part of the Kavango River basin. More than 160 000 inhabitants lived in the Namibian segment of the basin, most of them in Kavango Region. The main economic activities are mainly related to agriculture, cattle and fishing. The flood events in the region have been associated Kavango especially to the overflow of the Kavango River, affecting the Kavango River basin population and crop/grazing fields located in the northern belt of the region. During the 2009 floods, the water level in the Kavango River at Rundu was more than seven meters, much higher than normal and also higher that the occurrence of floods during the previous Kavango River flooded. Rundu, March 2009. year 2008. About 6000 people were affected and approximately 5000 were relocated into 31 relocation camps. Also, several crop fields were destroyed and livestock were lost. The most affected area is located in the territory associated to the Kavango River. There is a high concentration of population along the river, mostly in informal settlements (traditional dwellings). Most crop and grazing fields occur closer to the riverside, but also scattered throughout the area. The flood prone areas are located in the Kavango river banks and the existing murambas near Koro village and from Ndonga Linena to Makandu village. The gravel road that connects Divundu with Rundu constitutes the division between the flood prone areas and higher lands. Similar condition applies to the Rundu – Nkurenkuru road. The southern part of the Region is not Flood prone areas near Kavango River affected by flood events.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 57
Northern Regions. Flood Risk Management Plan 2011
During the 2011 flood events, the main findings were: Mutwarantja Primary School and community: Mutwarantja village has 1600 inhabitants. On information given by Ministry of Education there are 306 learners affected in the school. The place is located approximately 3 km from the cross of Shambya gravel road. In the site investigation it was found out that Mutwarantja village is isolated from the main
land because the Kavango River flooded the surrounding lowest areas around the village causing that teachers can’t access the school, the same as the students that live in the surrounding areas. Recommendations: As proposal for solutions were identified some options: 1- Construction of a vehicular bridge. 2- Construction of a rustic pedestrian bridge. 3- Construction of a stone way. 4- Construction of a small school in the other side of the village. 5- Relocate the village outside the island. To make a decision on an acceptable option it is necessary to carry out a feasibility study, which will allow to choose the better possible option and to design the respective construction’s project to build the selected one. Gwagi Primary School in Kahengue Constituency: The school is located in the village of the same name; with the flooding the water reached 0.15 meters isolating the school. The school is currently relocated close to the road to Nkurenkuru in a provisional facility (tents) in Rupara Village.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 58 Northern Regions. Flood Risk Management Plan 2011
- According with information provided by Ministry of Education there are 200 learners affected. - Good technical conditions of the building, masonry wall, zinc sheet roof, cement floor, no technical infrastructure. - Accessibility: From the main road there is a path way of 2 km in regular conditions. There is a dense bush in the surrounding areas and there are wild animals like crocodiles and snakes in the water. The school was located in the middle of the housing area but the people have been migrating nearby the road looking for water and electricity accessibility. Recommendations: - Relocate the school to a high level area and closer to the students where it was authorized to build two classrooms. - Change the use of the building to other activities i.e. forestry. - Supervise the relocation of the school to the new area; supervise the building project (the current project is only for two classrooms) and the construction process. Ruu-rumwe Primary School and Church in Sikondo village in Kapako: Ruu-rumwe Primary School and Church in rainy season get surrounded by water and it is not possible the access it. - According with information provided by Ministry of Education there are 470 learners affected. - Good technical conditions of the building, masonry wall, zinc sheet roof. - Sanitation: The toilets facilities are being constructed by donation of the UNICEF. - Accessibility: From the main road there is a path way of 500 m in regular conditions.
Recommendations: - Construction of a gravel road of approximately 500 meters with some culverts for main access way. - Construction of a pedestrian way as secondary access in the back side of the building.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 59
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Mabushe Clinic, Mashare Constituency: Six km left from the Rundu-Divundu highway (km.62th) is the Mabushe clinic, 1km distant from the Mashare settlement and practically by the Kavango riverbank. The zone is flooded in rainy season making difficult the access to the building. It has been built a dike around the clinic to block the entrance of the river but the water are stemmed inside the dike. There is a borehole that provides water to the clinic and currently is covered by water.
Recommendations: - Improve the access road to the clinic. - Build a culvert to facilitate the water flow. - Improve the existing earth dike that surrounds the clinic and construction of a new dike where the river enters. - Increase the height of the borehole to avoid flooding. - Build a collector register to evacuate with a pump the water remaining inside the area of the dike. - To increase the level of the electric register that is currently submerged in the water. Makandu Primary School: 10 km from Mabushe Clinic is located Makundu Primary School, it is distant from the flooded area but is inaccessible for students that are living in the opposite site of the school due to the water from Kavango river obstruct the access way. The same happen to Makundu village with approximately 12 houses. The water level in the center of the flooded area reach 7 meter depth and cover an area of 200 meter wide, forcing the inhabitants to use canoes to move from one place to another.
Recommendations: - Relocate the small village opposite of the flooded area. - Supply a safe mean of transport for students moving between the two shores.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 60
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Karovo Fish Farm at Kangongo: 59 km away is located Nyangana, 5 km to the interception in Kangongo village is located Karovo fish farm that is flooded by the river.
Recommendation: - Build a dike increasing the height of the gravel road between the river and the fish farm. Biro Clinic in Mukwe constituency: In Biro Clinic, the main cause of the problem is that it was built very near to the riverside only 20 meters distant in dry season, been flooded by the river in rainy season reaching 0.3 meter from the ground level. The clinic provides services for people living 14 km around the place.
Recommendations: - Relocate the clinic in a high level area. - Relocate only the most affected ward in a close higher ground. - Build a containment wall replacing the net fence outside the building. - Build a closing wall in the observation ward to close the hall and create pedestrian access to communicate all areas with a same floor height.
Thipana Primary School, in Mukwe constituency: Thipana Primary School in Mukwe constituency is located in a low level zone and still flooded, without access to it. It is a solid building but wrongly allocated in a low-lying area near the river. According to information provided by Ministry of Education there are 95 learners affected who are attending classes in a 3 tents temporary facility.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 61
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Recommendation: - To permanently relocate the school in a nearby high level area, or - Create an up-leveled containment dike as well as up-leveling the access road
Divundu Regional Council Office: Divundu Regional Council Office and its neighboring community are isolated due to the access way is flooded.
Recommendation: - Increase in 1 meter the height of the gravel road, 200 meters long and 6.00 meters wide. Access road to Sarusungu river lodge and Immigration Police Office:
On April 19 was impossible to enter in the area, reason why was necessary to comeback by boat to enter in the place and evaluate the existing situation, finding the following: Inmigration office is not operating and the lodge can be visited only by boat. There is one kilometer of the road covered by water in 1.2 meters of depth aproximately. The water from the Kavango river have been covering this portion of the road for more than 3 month. The workers have to use boats to go to work, but according to some information given to the
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 62
Northern Regions. Flood Risk Management Plan 2011 group there is a possibility to create a path way trought the bush that has a high level making it possible the access to the lodge and inmigration office bordering through a high area. Recommendations: - Build a new gravel road with culverts. It is necessary a feasibility study to select the correct place for the access.
RISK MAP PROPOSAL The high and moderate risk zones are located almost completely in the northern belt of the Region along the Kavango River, limited in its southern border by the existing roads (Rundu – Divundu gravel road on the east side and Rundu – Nkurenkuru – Katwitwi road on the west).The differences between both zones (high and moderate risk) are related to the level of vulnerability existing (presence of population and infrastructure High Risk Zones (Divundu and Mukwe, Mabushe, Kayengona, Kapako, Bunya, Rupara and Nkurenkuru areas). In two areas the high risk zones are extended into the south following existing murambas, to the Koro village and in the Ndonga linena area. Moderate Risk Zones (Kahenge, Nankundu, Muroro, Neyuva areas). Low Risk Zones (rest of the region)
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 63
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RUNDU TOWN FLOOD RISK MANAGEMENT PLAN
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 64 Northern Regions. Flood Risk Management Plan 2011
4.2.2- Rundu Town
4.2.2.1- General Characterization Rundu is the capital of the Kavango Region, northern Namibia, on the border with Angola on the banks of the Kavango River. Rundu has approximately 76 000 inhabitants and lies about 1000 m above sea level. It is the commercial capital of the Kavango region. In 1936 it became seat of the local governor and replaced Nkurenkuru as capital of the Kavango district. The town has since grown into a multilingual town of the Kavango region. Rundu Airport, mostly used for tourism and cargo, is 5 km southeast of the town. Town boundaries The existing township area is mostly developed along the Kavango River, although the proclaimed town boundaries extend far into the south. The road to Katima Mulilo is in fact the southern border of the existing urban area, even though there is an accelerated residential development in the Ndama area located on the south side of the road. The Kavango River is the northern border of the existing township as well as of the proclaimed townlands. The south side of the area is mostly occupied by vacant lands, especially on the eastern part, while the western area is reserved for strategic uses. Use and occupation of the land. There is prevalence of vacant lands, especially on the south side of the proclaimed townlands and in the floodplains near the Kavango River on the northern part. The existing urban area is partially compacted with some scattered vacant lands; the prevalent land uses are residential, business and commercial buildings as well as social services. Residential areas: The oldest houses in Rundu are those in the Katutura area. These houses are mainly 2 bedroom homes with large backyards even though they are situated next to the CBD. On the west is Tutungeni, which means "let's build". This area was previously occupied by executives of the white-dominated business place, but now it is open for any willing buyer in need of a quiet neighborhood. On the East is Safari. These are the middle-priced houses and were built in the 1970s. These three main localities dominated Rundu residential life until the turn of the millennium in 2000, when new housing projects by O'B Davids Properties built a new residential area named Millennium Park. After which two others have been built by the NHE, Queens and Kings Parks respectively. Outside the formal suburbs shanty towns symbolize the rapid urbanization of the town: Kehemu, Sauyemwa and Ndama are the most informal areas while a fourth, Donkerhoek (Dark Corner) is rapidly becoming formal since the start of the Build Together Campaign in 1992.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 65
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Social services: The Rundu State Hospital is situated in the center of the town, off Markus Siwarongo Street. It's the largest hospital in the region. There are four tertiary Institutions in Rundu, namely Rundu College of Education, Rundu Vocational Training Centre, NAMCOL and Triumphant College. The University of Namibia and Polytechnic of Namibia both maintain centers that provide support for students who are studying on distance. There are five Secondary schools in the town namely, Rundu secondary school, Dr. Alpo Mbamba Secondary School, DR Romanus Kampungu Secondary school, Noordgrens and Kamunoko Secondary school and about 20 primary schools.. Rundu Open Market is the most well-known and biggest open market in the town. It was founded in 1996 through cooperation between the government of Namibia and the government of Luxembourg. Technical services Water Supply: Namwater is the main supplier of water to the town, with two treatment plants and four water tanks. Drainage: No drainage system is in place. Sewerage: There is a system in place that covers most of the urban area, while some buildings have partial solutions (Police, Lodges). The final destination of the sewerage network is a recently completed oxidation pond system located on the south part of the town, which was built as result of the necessity to relocate the old oxidation ponds located on the north east, due to the contamination of the river during flood events. However, some problems are still affecting the proper performance of the system, with the persistence of dark water inflow into the old oxidation ponds due to the malfunction of one pump station, while the new ones affect the neighboring residential area of Ndama with bad odors. Communication: The town area is fully covered by communication services. Electricity: There is a power station (NORED) in the Ndama area that serves the whole town area.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 66
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4.2.2.2- Situation Analysis Rundu town is affected mostly by heavy rains, which provoke some damages due to the prominent slopes, aggravated by the lack of a proper underground storm water drainage system. The rainwater provokes serious erosion problems in many areas and roads located near to the river banks. The Maria Mwengere road is the most seriously affected. The town’s northern part is flooded by the overflow of the Kavango River, affecting mostly illegal High erosion in a road close to Kavango river banks. settlements and accommodation services (lodges). The most affected residential area within town boundaries is the informal settlement of Kehemu, located on the most eastern part of Rundu and north of the main tarmac road leading to Divundu. The zone is a low lying area and no storm water drainage system exists. As a result, storm water normally gathers in certain parts affecting several households. The settlement is under a formalization process Dumpsite in a low-lying area in Kehemu informal which considers the upgrading of its living settlement. conditions. Floods affected communities located outside town boundaries, which are relocated to the Old Golf Club during emergency. There are proposals to relocate permanently all those communities within town boundaries. In the southwestern town areas the flooded stream affects accessibility to primary schools located in the Ngwagwa/Kansukwa villages, which is attended by many learners from the Sauyemwa and Kasote areas, due to the fact that the primary schools located in those settlements are overcrowded. The bridge that allows the crossing over the stream is very risky and unsafe for small children and old people. The flooded stream water is contaminated with dark waters
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 67
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 68
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 69
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 70
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 71
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NKURENKURU TOWN FLOOD RISK MANAGEMENT PLAN
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Pageage 72 Northern Regions. Flood Risk Management Plan 2011
4.2.3- Nkurenkuru Town
4.2.3.1- General Characterization The urban development of Nkurenkuru and Kahenge are located on the recently tarred Rundu- Nkurenkuru road section, approximately 130 Km. to the west of Rundu, the regional seat of the Kavango Region. The Nkurenkuru urban development falls within the Mpungu Constituency, the Kahenge urban development falling within the Kahenge Constituency. The town is strategically located alongside the Kavango River linking Kavango Region with Ohangwena and Oshikoto Regions and via Katwitwi border post to the most densely populated area of Kwando-Kubango Province in the Republic of Angola. The town has become the residential, business and administrative center on the eastern part of Kavango region with an increasing influx of people into the town. The residential area are developed more to the southern and eastern part of Nkurenkuru, while the existing commercial and institutional nodes are situated closer to the Okavango River where trading and commercial activities do exist. The population of the town is estimated in 7 500 inhabitants. In the Kahenge Constituency near the Kavango River the municipality implemented an area for extracting sand as building material which it has serious problems of erosion, affecting structure of soils and natural vegetation in this area. Hydrology: The main hydrological feature of Kavango Region is the Okavango River. The Cuito River, a tributary, joins the Kavango River from Angola at Dirico, so flow volumes are greater downstream of this point. Apart from this difference, hydrological features of the upstream section are similar, but not identical, to the aforementioned description. One important difference is the timing of flooding and the contribution of each tributary (Mendelson and Obeid 2003). The Okavango River at Rundu experiences its highest water from January to May, with the peak in April, in response to summer rain falling in the upstream catchment and making its way downstream. Water in the Cuito is delayed by a longer period and peaks in about May, with a smaller peak. The Okavango brings in much more water during floods and then its level drops for the months of June to November. The Cuito peak is relatively much less than the Okavango, but this river contributes more to the downstream flow during flow during the months of June to November. The Omarumba that enter the valley of the Okavango River hold water for short period, up to about 4 months depending on the summer rains, and water might even flow for short distances in them, but otherwise they are not active rivers at all.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 73
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Underground water: There are a number of aquifers in the Kalahari sediments in the region, which range in epth from about 20 m. in the areas around Okavango River, to 350 m. in some places (Obeid & Mendelsohn, 2001). These aquifers recharge by groundwater flowing in a northerly direction from the more elevated areas to the south of the region (Obeid & Mendelsohn, 2001). Most of the groundwater in Nkurenkuru town lies about 20 m., largely due to the close proximity to the Okavango river and the general northerly flow of groundwater. Boreholes in the region produce between 1 and 5 m3 , which is generally adequate from the small settlements in the region (Obeid & Mendelshon, 2001). This water is generally of good quality, with total dissolved solid (TDS) values of less 1 000 mg/l (Obeid & Mendelsohn, 2001) (1). Agriculture: The Council has identified an area to the north of Kahenge where an existing agriculture project is located for the development of additional agricultural activities, generating employment of approximately 200 to 2050 workers plus a large number of casual workers needed during harvesting times the indirect benefit of such project lies in the supporting industries which can provide an additional 500 to 650 employment opportunities. Water and sanitation: The boreholes and installations provided by the Directorate Rural Water Supply and the elevated tanks (Reservoir) constructed by Namwater ensures a steady and regularly available supply of potable water. Various types of pipelines, related structures and equipment up to and including the bulk supply water meters, to ensure the provision of potable water for the residents of the town of Nkurenkuru is currently in place. Sewage disposal is conducted by the Council at the moment, the Nkurenkuru oxidation ponds located within the western part of the Townlands area. It was indicated that Council is looking for new site to construct a properly designed sewerage works to service the Town of Nkurenkuru. Electricity: Nkurenkuru is serviced with electricity which is supplied and managed by NORED, who is currently the service provider for the northern part of Namibia. Electricity is provided from the Rundu substation along the C 45 Minor Route by means of an 11 kVa overhead line. Nkurenkuru is serviced with a kVa overhead power lines situated in the road reserves of the internal street layout of the town. Solid waste: The present municipal dump site is located 6 Km. to the south of Nkurenkuru, access to the site obtained from the road leading to Nepara. The Town Council has indicated that the present dump site is not properly managed and needs to be either upgraded or closed. Postal services and Telecommunications: Nampost currently have a bureau located at the Nkurenkuru SME center. The centre is located within the existing CBD area for Nkurenkuru. Daily pickups and deliveries are made from Rundu to Nkurenkuru by NAMPOST. The residents in Nkurenkuru have aces to either private or public phones. A MTC broadcasting tower can be found on the northern side of the gravel road to Nepara, resulting in a strong cellular connection throughout the whole of Nkurenkuru and Kahenge.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 74
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4.2.3.2- Situation Analysis The majority of the areas affected by the overflow of the Kavango River are vacant at the present time, but have been planned for different land uses without considering this problem. In the Kahenge Constituency near the Kavango River the municipality implemented an borrow area for extracting sand as building material which it has serious problems of erosion, affecting structure of soils and natural vegetation in this area. A revision of the existing plans is necessary and a new town scheme is required considering the environmental aspects in order to avoid damages to possible future developments in the area. Nkurenkuru river side at pump station in Mpungu Constituency: The site is located approximately 500 meters from the town council offices. The water level reaches the toilets in the recreational area, due to its location in a low level area contaminating the surrounding waters. The pump station is near to be reached by the water of the Kavango River.
Recommendations: - Relocate the toilets in a higher level area. - To move the fence of Nkurenkuru beach recreational area according to regulations. - To fill up with well compacted soil the area in the side of the pump station front to the river.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 75
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 76
Northern Regions. Flood Risk Management Plan 2011
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Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 78
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 79
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CUVELAI BASIN FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 80 Northern Regions. Flood Risk Management Plan 2011
4.3- CUVELAI BASIN
4.3.1- Territorial Context
4.3.1.1- General Characterization The Cuvelai basin encloses an extensive area located in the south of Angola and in the north of Namibia. In the Namibian side, the basin covers the north-eastern part of Omusati Region, northern part of Oshana and Oshikoto Regions and the western part of Ohangwena Region. The Cuvelai system is characterized by shallow depressions or oshanas which fill up with surface water during the rainy season. The Cuvelai originates in Angola with its catchments falling between the Kunene and the Kavango " Okavango drainage system. The system is fed by a number of rivers, some of which have their headwaters as far north as the Encoco highlands in Angola, which receive on average over 800 mm of rain a year. As these seasonal waters move southward, the land becomes flatter and the rivers and channels meandering towards the Namibia border feed into each other at some places and part ways at others, forming a massive inland delta. Physical and Geographic Characteristics The endorheic drainage to Etosha Pan is the most important hydrological system in the northern region, it comes from the Cuvelai basin from Angola and it is responsible of the extremely floods in these entire regions also with heavy rain fall average. The Etosha pan is a large endorheic salt pan. The 120-kilometre- long dry lakebed and its surroundings are protected as Etosha National Park, one of Namibia's largest wildlife parks. The pan is mostly dry but after a heavy rain it will acquire a thin layer of water, which is heavily salted by the mineral deposits on the surface of the pan, which most of the year is dry mud coated with salt. All the rivers (oshanas) of the interior are episodic in character, flowing sporadically and rapidly during the periodic intense rain showers. These seasonal flows provide fishing grounds, renew pasture and recharge ground water supplies. The oshanas in the Omusati region are much boarder and flatter than in the Oshana and Oshikoto regions, where there are several channels closer to each other. Most channels come together further south in a few main watercourses and eventually flow into the Etosha Pan via the Ekuma River.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 81
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Geology The geology of the territory is characterized by sand stone and calcrete, while soils are mostly red fersialitic sand and loam and arenosols (inland sands, alluvial and other weakly developed soils, alluvium enriched with organic material, mainly grayish and dark alluvial sand and loam). Soils in the Cuvelai basin are generally nutrient-poor and are often saline. With the exception of the Namib Desert, groundwater occurs in varying quantities over almost the entire territory. In some areas artesian springs occur, while pans and sand deposits along several river courses serve as ideal reservoirs for usable water. In certain areas the withdrawal of groundwater is controlled in order to prevent over-exploitation and a further lowering of the groundwater table. Often the groundwater is virtually unusable due to the presence of dissolved solids derived from the rocks in which the water is stored. Specific concentrations of fluorides, nitrates and sulphates further affect the usability of the water. Using the World Health Organization’s criterion for general human consumption of 200- mg/liter concentrations of TDS (total dissolved solids) as a guideline it is clear that most of the subterranean water resources are indeed usable. The predominant natural vegetation is forest savanna and woodlands, which occurs in the north and northeast part of the country, along the border with Angola, Zambia and Botswana, including Ohangwena, Kavango, and Caprivi Region, as well as Mopane Savanna in the Oshana and Omusati regions. Population The population in the regions located within the Cuvelai basin area is estimated to be 862 872 representing over 35% of the total population of Namibia. Total Region Rural Population Urban Population Population % total % total inhabitants inhabitants inhabitants region region Oshana 176 586 121 844 69.0 54 742 31 Omusati 243 658 241 221 99.0 2 613 1 Ohangwena 261 324 258 711 99.0 16 317 1 Oshikoto 181 304 164 987 91.0 2 437 6 Total 862 872 786 763 91.2 172 542 14.3
The rural population is predominant in all the regions, especially in Omusati, Ohangwena and Oshikoto. The rural population in those three regions is 664,919 inhabitants, the 77% of the total population living in the area.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 82
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Settlement Patterns The settlement pattern in the area covered by the Cuvelai basin is as follows: Towns: 8 (Oshakati, Ongwediva, Ondangwa, Eenhana, Helao Nafidi, Outapi, Oshikuku, Okahao) Settlement areas: 11 (Okalongo, Ogongo, Tsandi, Onesi, Ongenga, Omungwelume, Okongo, Eheke, Uukwangula, Onayena, Oniipa) Nowadays there is prevalence of disperse population and housing and the existence of few settlements with concentrated population. Those settlements are not strong enough to attract and motivate disperse residents to immigrate to them. At the same time, there are other aspects such as local and family traditions, social integration, economic activities, and poverty status. Population in the Cuvelai Despite the previous figures, no all the population is directly exposed to the hazards of the volume of water coming through the Cuvelai basin. The number of people living in the area is estimated in 730 915 inhabitants, with a high incidence of population of Ohangwena and Oshana regions living a high risk zones. Main urban areas The most important urban areas located in the Cuvelai basin are the towns of Oshakati, Ongwediva, Ondangwa (in the Oshana Region) and Helao Nafidi, in the Ohangwena Region. The rest of the urban areas are located in the Omusati Region: Outapi, Oshikuku and Okahao.
4.3.1.2- Situation Analysis The natural causes of the flood events in the regions located within the Cuvelai basin area are diverse, the most important are:
! Floods that occur in the Cuvelai basin, hydrographic system made of an important number of oshanas that evacuate the water resulting of the rainfall in the basin, which mostly is located in Angola, but with a very important presence in Oshana, Omusati, Oshikoto and Ohangwena regions.
! Heavy rains that occur in a short period of time in all the affected regions.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 83
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Main causes of floods in the Cuvelai basin area The vulnerability related to these natural hazards increases due to several factors, such as:
! Presence of disperse population and human settlements in flood prone areas associated to the Cuvelai basin.
! Modification of the natural environment through the construction of new roads without proper environmental impact assessments to protect them and to preserve water courses through natural ways, building the necessary facilities, such as culverts and bridges with the required proportions.
! Existence of informal settlements in the main urban centers located in the water natural ways, blocking the water courses.
! Insufficient maintenance of the storm water systems (natural or man-made), with the presence of obstructions in culverts and channels.
! Lack of proper Master Plans in the urban centers that consider storm water systems solutions and land use regulation.
! Poverty status of an important population segment.
! Fragility of building materials used for houses construction in rural areas.
! Irregular land use process.
! Low perception of the flood risk.
! Traditions, way of life of local population.
Risk Zones According to the level of risk, it is possible to identify three different zones within the Cuvelai basin, with the following classification: High Risk Zones: Areas located in flood prone areas with high vulnerability. Moderate Risk Zones: Flood prone areas (low lying areas) affected specially by rains with moderate vulnerability. Low Risk Zone: High lands and low lying areas with low vulnerability.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 84
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The population residing in each zone is shown in the following tables:
POPULATION RESIDING IN HIGH FLOOD RISK ZONE: 468 489 inhabitants Omusati Region Constituencies Population Okalongo 28 719 Oshikuku 8 299 Etayi 35 130 Elim (East): 30% 3 255 Total 75 403
Ohangwena Region Constituencies Population Ongenga 21 706 Engela 21 832 Oshikango 25 221 Ohangwena 17 887 Endola 24 804 Ondobe 22 253 Omulonga 31 465 Eenhana (West & South): 30% 5 607 Total 170 775
Oshana Region Constituencies Population Okatana 15 325 Oshakati West 19 862 Oshakati East 24 269 Ongwediva 26 700 Okaku 20 354 Ondangwa 31 694 Uukwiyu 12 047 Okatyali 2 812 Ompundja 4 448 Uuvudhiya (North): 70% 3 064 Total 160 575
Oshikoto Region Constituencies Population Oniipa 24 730 Onayena 15 459 Olukonda 9 226 Onyaanya (North – West): 60% 12 321 Total 61 736
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POPULATION RESIDING IN MODERATE FLOOD RISK ZONE: 193 826 inhabitants Omusati Region Constituencies Population Anamulenge 12 617 Ogongo 19 611 Elim (West): 70% 7 595 Outapi 31 496 Tsandi (East): 70% 18 934 Onesi (North): 80% 10 396 Otamanzi (North): 70% 9 184 Ruacana (North – East): 60% 6 722 Okahao (North – East): 50% 8 875 Total 125 430
Ohangwena Region Constituencies Population Omundaungilo 8 115 Eenhana (East): 70% 13 083 Epembe (North – West): 80% 11 888 Okongo (West): 30% 6 465 Total 39 551
Oshana Region Constituencies Population Uuvudhiya (North): 20% 875 Total 875
Oshikoto Region Constituencies Population Omuntele (North): 70% 10 612 Onyaanya (South): 40% 8 214 Okankolo (West): 70% 9 145 Total 27 971
POPULATION RESIDING IN LOW FLOOD RISK ZONE: 68 600 inhabitants Omusati Region Constituencies Population Ruacana (South – West): 40% 4 481 Tsandi (West): 30% 8 114 Okahao (South – West): 50% 8 875 Otamanzi (South): 30% 3 936 Total 25 406
Ohangwena Region Constituencies Population Epembe (South-East): 20% 2 972 Okongo (East): 70% 15 085 Total 18 057
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 86
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Oshana Region Constituencies Population Uuvudhiya (South): 10% 438 Total 438
Oshikoto Region Constituencies Population Omuntele (South): 30% 4 548 Omuthiyagwiipundi (North – 7 102 West): 30% Eengondi (North – West): 60% 9 130 Okankolo (Central): 30% 3 919 Total 24 699
TECHNICAL INFRASTRUCTURE AFFECTED The flood events in the Cuvelai basin area have a high impact on the technical infrastructure, especially road network and sewerage systems and, in lower extent, water supply systems. The communication and electricity systems are not seriously affected, except in the accessibility to some related facilities. Roads: Road network in the area covered by the Cuvelai could be considered as one of the main man-made causes of the high damages produced by floods, due to the alteration of natural water ways, insufficient number of culverts and bridges, as well as the small capacity of existing and new culverts. At the same time, roads are one of the most important infrastructural elements affected by floods. According to the local knowledge, in some zones (rural areas of Omusati and Ohangwena regions) “roads are the main responsible of floods and most of the culverts are not located in the correct natural water way”. Sewerage systems: Oxidation ponds with final water evaporation have proved to be vulnerable structures during flood events. Many of these systems break and/or overflow, spilling raw or insufficiently treated sewage into the surrounding, lower lying, densely populated areas, turning out to be a serious health hazard. Additionally, several sewerage pump stations are under water during the floods. To provide safer living conditions for the population living in areas at risk, especially in the major urban centers, the oxidation ponds should be replaced with modern biological treatment technology.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 87
Northern Regions. Flood Risk Management Plan 2011
Main urban centers affected by floods Oshakati is the capital of the most densely populated Oshana Region; it is the most developed town in the area covered by the Cuvelai basin in northern Namibia. Oshakati has experienced much development since Namibia achieved independence, so business and trade are now vital elements in the economy. The town is seriously affected by annual flooding, problem that is aggravated because the city is expanding, so more houses and company buildings are suffering from these floods every year, it constitutes the most vulnerable urban center in the whole country in aspects related to Flood areas in Oshakati town floods events. During flood events, large parts of the town are submerged for many weeks, affecting an elevated huge number of populations. The degree of affectations is very high. The concentration of a large number of population, business, and infrastructure in a very vulnerable area to floods is a permanent hazard for the town. The most important elements that increase the vulnerability to floods events in Oshakati are related to the low capacity and obstruction of existing culverts and bridges (close to Santorini Inn., Okandjengedi bridge, Oneshila), shallow oshanas, which provoke flooding of nearby zones, presence of informal settlements and buildings in natural water ways and in flood prone areas (Eemwandi, Sky, Oshoopala), as well as the obstruction of natural water ways by debris, garbage, vegetation and inadequate digging. The informal settlements (Oshoopala, Uupindi, Oneshila and Sky) are the most affected areas. The sewage system is also affected, some pump stations are flooded. The oxidation ponds are overflowed and damaged. Oshoopala: Oshoopala area is an informal settlement, located in low areas; where there are around 10 000 people living. The place is almost entirety under water.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 88
Northern Regions. Flood Risk Management Plan 2011
Kandjengedi: Before the beginning of the floods it was built a curtain that prevented that the area was not strongly impacted by the flow of the waters. Only a small part of the area was affected due to the break of a part of the curtain.
Oneshila: It is the worst flooded place in the whole area. It is the lowest part in the Oshana that accumulates all the water and for that reason the school of the area has been disabled. The housings and the roads system have been disabled too.
Generally, houses in the informal areas of Oshoopala, Oneshila and Kandjengedi are of masonry walls or zinc walls, zinc roofs and earth floors. The area is flooded because it is framed among the road that is located in one of the borders of Oshoopala area and the earth curtain of Kandjengedi area. Both elements make the water pass through Oneshila area to one of the bridges of Oshakati Main Road. The reference bridge is small with 6 culverts. The bridge doesn't cover more than 20 meters and the oshana has 200 meters approximately and for that reason the evacuation capacity of the bridge culverts is not enough. Upindi It is a low area that was affected due to the extension of the waters in the oshana with the increment of the rains and the overflow of the river. The rest of the affected urban areas are analyzed in their Regional chapters.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 89
Northern Regions. Flood Risk Management Plan 2011
Main settlement areas affected by floods Okalongo Settlement Area (Omusati Region) Okalongo is one of the four settlements of Omusati Region; it is the capital of the Okalongo Constituency, located near the Angolan border. The settlement is located along the Anamulenge-Engela gravel road, about 30 Km north-east of Outapi. The population is estimated in almost 500 inhabitants. There is a direct access through a tarred road from the town of Oshikuku, distant 30Km, allowing an easy link to the Oshakati-Ruacana road, the most important one in the region. Due to its condition to be center of the constituency and the proximity to the Angolan border, has made that the settlement is mostly occupied by commercial and business development, although it is important to highlight the presence of several educational institutions which are attended by many learners from different nearby areas. The traditional settlement is surrounded in the west side by a large flood prone area with several oshanas principally in Yanadjaba area, very close to the oxidation pond of the settlement. During rainy season, the whole settlement area is very affected by floods, with a high degree of vulnerability, due to the presence of many residential and commercial buildings within the flood prone areas. Numerous houses and service facilities are affected mainly by the absence of drainage solutions as well as for being inside the oshana. Most of the houses are brick and sheet made placed on no regular urban order along dirt roads of small section. Many of the existing social and commercial services (schools, hospital and supermarkets) are surrounded by water and are accessible only through temporary pathways. In cases waste water has mixed along with flood waters, a school had to be closed due to health hazard. Those who cannot afford the direct water supply use public taps or the very contaminated water from the oshana and with regards to electricity, it’s the same provided to those able to afford it while there’s no solution to keep waste water from mixing with flooded waters. Main roads are those from Engela to Utapi and from Oshikuku as well as a gravel road across town S-W also from Oshikuku, other sections of roads are cut off leaving houses and services facilities with no access.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 90
Northern Regions. Flood Risk Management Plan 2011
Ongenga and Omungwelume settlement areas (Ongenga constituency, Ohangwena Region) The major problems are in the technical infrastructure, with the Oshakati – Omungwelume bridge washed away, while the oxidation ponds are affected. Eheke Settlement Area (Ondangwa constituency, Oshana Region). Several households are affected and many residents are displaced to other areas, while several crop fields total and partially destroyed. The Eheke clinic is isolated during flood events, causing inconvenience to the delivering of medical materials. Some infrastructure is also affected, with a number of pump stations under water, while the Okapya-Eheke-Onakawandi gravel road is washed away and the gravel road alongside Eheke Secondary school and Eheke settlement areas are under water. Inner roads were surpassed by flood waters and some of them were washed away. The number of culverts is not enough for the evacuation of the flowing waters. In other visited roads numerous sewers and a bridge have been built and flood waters pass through them with great speed. A part of those waters accumulates and stagnates in the area. There is not enough drainage solutions which make difficult the water pass through and in case of the settlement school those solutions disabled the access road to this installation. Uukwangula Settlement Area (Okatana constituency, Oshana Region) Several houses are affected, while some health centers are surrounded by water. At the same, mahangu storages are affected and crop fields are under water. Access roads and bridges located in the area are in good conditions. The extension area for housings in these moments is flooded and it is advisable to relocate it in higher areas. It is necessary to take all the provisions to keep the water from passing through the areas of perspective development of housings, business and services. There is a Sewers Pumping Station that will be interconnected with an Oxidation Pond (at this time it is under construction) There is a Football Stadium located in high areas of the town that has light affectations due to the heavy rains.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 91
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 92
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 93
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 94
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 95
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 96
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 97
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OSHANA REGION FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 98 Northern Regions. Flood Risk Management Plan 2011
4.3.2 – OSHANA REGION
4.3.2.1- Regional Context
4.3.2.1.1- General Characterization Location: Oshana Region is located in north- central Namibia and constitutes only 0.6 per cent of Namibia’s total area. The neighboring regions are Omusati in the west, Ohangwena in the North, Oshikoto in the east and Kunene in the south. Physical features: Oshana is the smallest of Namibia’s thirteen regions. Its southern section consists of an area west of Etosha Pan within the Etosha and incorporate approximately one third of the region. The average is 400-500 mm, falling largely during the rainy season between November and March. The northern part of Oshana Region is the most densely populated and includes the large, sprawling urban center of Oshakati the regional capital, Ongwediva and Ondangwa, 33 kilometers to the south-east. They are second only in population density to the capital, Windhoek, and combined they form by far the biggest urbanized area in all four of the North-Central regions. The most predominant geological formation in this region its: Sandstone and calcrete from period tertiary to quaternary- cretaceous, sequence Post-Karoo Complexes; Group Kalahari; + - 65 million years. In some parts of this region occurs: Sandstone / Shale mixed with sandstone and calcrete, from period Carboniferous to Jurassic, sequence Karoo; Group Ecca; + " 345 " 140 million years. Vegetation: There is predominance of Savanna vegetation: Mopane Savanna. Climate: The average rainfall in Oshana ranges between 400 mm- 500 mm, with a frequency of rainfall of 30 – 50 days with rain. The rainfall variability (average deviation as % of annual average) is 35 -40 %. The seasonal distribution of rainfall is from October to March with an annual average of 80 – 90 %. The length of rain season is 4 – 5 months considering the number of months per year with more than 50 mm. of rain. Size of the Region: The region covers a total area of 5 291 km2 (0.6 % of the total land area of Namibia) Population: The population of the region is 161 196 inhabitants and a density of 18.7 people per Km2 (Namibia average is 2.1 people/Km2) with largely female headed households (54 %). The northern part of Oshana Region is the most densely populated and includes the large, sprawling urban center of Oshakati the regional capital, Ongwediva and Ondangwa, 33 kilometers to the south-east. They are second only in population density to the capital, Windhoek, and combined they form by far the biggest urbanized area in all four of the North- Central regions. Households: The population resides in 29 851 households, with an average size of 5.4 people per household.
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Administrative structure: The region is divided into 10 constituencies (Okaku, Okatana, Okatyali, Ompunja, Ondangwa, Ongwediva, Oshakati East, Oshakati West, Uukwiyu and Uuvudhiya). The administrative capital of the region is the town of Oshakati, which is the most important urban centre in the northern part of Namibia. Settlement patterns: About 70% of the population in Oshana region lives in rural areas. The human settlement system is classified as follows: Towns: 3 (Oshakati, Ongwediva, Ondangwa) Settlement areas: 2 (Uukwangula, Eheke ) The rest of the region’s population resides in a scattered way in rural areas (homesteads, isolated houses, etc.). Population and households’ distribution per Constituencies (Source: 2001 Census)
Constituency Population Households Average size Okaku 20 354 3 330 6.1 Okatana 15 352 2 430 6.3 Okatyali 2 812425 6.6 Ompundja 4 448 714 6.2 Ondangwa 31 694 5 802 5.1 Ongwediva 26 700 4 988 5.3 Oshakati East 24 269 4 846 4.7 Oshakati West 19 862 4 259 4.6 Uukwiyu 12 047 1 899 6.3 Uuvudhiya 4 378 864 5.1 Total 161 916 29 557 5.4
4.3.2.1.2- Situation Analysis The rural areas located on the northern part of the region are densely populated, so there is a high degree of damages to people’s lives and properties, as well as social services (schools, clinics). The less populated central areas are characterized by subsistence farming and few settlements, so the major affectations are mostly related to the loss of crops and livestock. In both cases, during flood events, many roads are washed away and some communities are isolated on islands in the middle of pools of water (Okatana Mission, Endola, Ompundja - Omeege). Most of the water coming from the Cuvelai basin that affects the northern part of the Oshana Region crosses the Okatana area. Those waters flood Oshakati, Ongwediva and Ondangwa Towns, and their surroundings.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 100
Northern Regions. Flood Risk Management Plan 2011
The Etale Lyambango bridge is in the road from Oshakati to Ompundja. The bridge was covered by the waters and one of the accesses to the bridge was destroyed by them. After several days the water remains passing on a part of the bridge what indicates that it should be reconstructed with the purpose of elevating the level of its circulation board. The degree of affectations in Oshakati town is very high. The concentration of a large number of population, business, and infrastructure in a very vulnerable area to floods is a permanent threat for the town. The majority of the affected communities in Ongwediva were areas that were not planned. Surrounding areas were isolated due to access roads were cut off and some households were affected, especially in informal settlement located in the town’s periphery (Sky location). Low lying areas between town and nearby areas in The main impact of flood events in Ondangwa Ongwediva were related to extremely high rainfall, which provoked large quantities of water accumulated in low-lying areas of the town with the result that numerous houses, commercial and industrial buildings were affected by storm water. Storm water entered the sewerage network and oxidation ponds filled completely causing them to overflow to the nearby oshanas. In the rural areas, roads were washed away Low-lying areas in Ondangwa town and some communities were isolated on islands in the middle of pools of water (Okatana Mission, Endola, Ompundja - Omeege). The most important elements that increase the vulnerability to floods events in Oshakati are related to the low capacity and obstruction of existing culverts and bridges (close to Santorini Inn., Okandjengedi bridge, Oneshila), shallow oshanas, which provoke flooding of nearby zones, presence of informal settlements and buildings in natural water ways and in flood Bridge over oshana in Oshakati town prone areas (Eeminandi, Sky bridge, Oshoopala), as well as the obstruction of natural water ways by debris, garbage, vegetation and inadequate digging.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 101
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In Ongwediva, the main problem is related to the lack of accessibility to surrounding areas during flood events (Sky settlement), because of the lack of proper solutions (culverts and bridges). The local authorities are carrying out a relocation process of people living in informal settlements (Sky location) located in flood prone areas. As the same time, a new storm water drainage system (Extension 11) is under construction. The town planners are working in the identification of high lands during flood New storm water drainage system under events, land acquisitions and preparation of urban plans construction in Extension 11 in Ongwediva considering new roads, subdivision and infrastructure, together with the implementation of programs to help people in housing construction (Shack Dwellers Federation, Build Together Program) and assessment in building construction. The Town Master Plan is reformulated, incorporating new approaches related to floods.
New houses in high land for relocated people from flood prone areas in In Ondangwa, floods are mainly provoked by heavy rains and the lack of storm water drainage system, affecting low lying areas within town borders and accessibility to surrounding areas (Ondivala settlement). Due to low level of sewerage manholes, storm water mixed up with sewerage water by creating a Low-lying areas flooded by rainfall in Ondangwa serious health risk to the people living nearby.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 102
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RISK MAP PROPOSAL High Risk Zone: The complete Region is classified as a high risk zone, although some specific areas could be considered as moderate risk zones (Ondangwa town) and low risk zones (southern constituencies – Uuvudhiya, Okatyali, Ompundja). Moderate Risk Zone: Ondangwa town. Floods due to the presence of low lying areas within town borders. Low Risk Zone: Southern part of the region, mostly because of low vulnerability (few number of population, presence of Etosha National Park)
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 103
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ONDANGWA TOWN FLOOD RISK MANAGEMENT PLAN
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 104 Northern Regions. Flood Risk Management Plan 2011
4.3.2.2 – Ondangwa Town
4.3.2.2.1- General Characterization Ondangwa town is located right in the eastern boundary of the Oshana region, bordering the Oshikoto region. It is an important urban center with easy accessibility to the Oshakati town, the most important urban area on the north part of the country, to the Helao Nafidi town, on the Angolan border where high trade and commercial activities are taking place and to the capital city, Windhoek, through the B1 trunk road. The population is estimated in 45 000 inhabitants. The landscape is flat, monotonous and dotted with settlements. Mopane, marula and wild fig Wild fig trees turn up occasionally between the fields and the kraals and one can also find Makalani palm trees here (symbol of the Ovambo area). After heavy rains in the region, many little lakes and ponds form. The water comes from the Cuvelai basin reaching from the north to the Etosha Pan. Ondangwa town is the district capital of the Ondangwa electoral constituency, although the Constituency office is located in the settlement area of Eheke. Ondangwa features a shopping centre, a large open market, and several tourism facilities. Many local authorities for the Oshana and Oshikot regions are placed in the town, e.g. the Ministry of Education and police. The hospital is placed in the nearby town of Oniipa. There are several schools in the town, among them Andimba Toivo ya Toivo Senior Secondary School. Some schools extend farthest from the town - for instance Ekulo Senior Secondary School. Since independence, the government has settled up an industry in the north, to create jobs and improve the poor infrastructure. Rossing Foundation, Kayec and Cosdec are the three vocational skills schools training young people in building maintenance, sewing, cooking, and Internet Technology. In 2001, planning started on a railway line to link Tsumeb with Ondangwa, with extensions to Angola planned to follow. The town shares an airport with Oshakati. Ondangwa is linked to Oshakati and Oshikango by a tarred road. Town boundaries: The existing township boundaries comprise several planned and unplanned areas. Ondangwa town has a particular fact related to its eastern boundary,
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 105
Northern Regions. Flood Risk Management Plan 2011 which is at the same time the regional boundary between the regions of Oshana and Oshikoto, with a populated area in the Oshikoto side with strong ties to the township, including the presence of a hospital which serves population of both sides. Use and occupation of the land; There is a prevalence of the informal residential and vacant land uses within existing town boundaries, with the businesses located mostly along the B-1 road. Residential areas: Most of the houses are located in informal settlements disseminated throughout the town area as well as in planned land (extensions). Social services: Onandjokwe Hospital, Oluno Clinic (public), private clinics, 4 Primary schools, 2 Secondary Schools. Technical services Water Supply: There is a major pipeline that brings the water from Oshakati (NAMWATER), serving most of the urban area with a reticulated network, except in some informal settlements, where the service is through communal taps. Sewerage: The existing system serves most of the planned areas through reticulated network, pump stations and oxidation ponds. The informal settlements are not served by sewerage; the solutions are through septic tanks, pit latrines and others. Drainage: No drainage system is in place, only partial solutions especially along the main road. Communication: The town has accessibility to selected services/facilities. These include television, radio, newspaper, telephone and computer. Electricity: Most of the town is served by electricity (NORED), although some areas within the existing informal settlements are not yet served.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 106
Northern Regions. Flood Risk Management Plan 2011
4.3.2.2.2- Situation Analysis The main impact of flood events in Ondangwa were related to extremely high rainfall, which provoked large quantities of water accumulated in low-lying areas of the town with the result that numerous house2s, commercial and industrial buildings were affected. Storm water entered the sewerage network and oxidation ponds filled completely causing them to overflow to the nearby oshanas. Low-lying areas in Ondangwa town In Ondangwa, floods are mainly provoked by heavy rains and the lack of storm water drainage system, affecting low lying areas within town boundaries and accessibility to surrounding areas (Ondivala settlement). Due to low level of sewerage manholes, storm water mixed up with sewerage water whereby creating a serious health risk to the people living nearby. Town affected by the waters that come from Omashaka to Onguta and to the town. The waters go into the flooded area passing through 5 culverts located under the railroad. The waters flow slowly from the oshanas that are Low-lying areas flooded by rainfall in Ondangwa beyond the railroad. It also exists, in that place, a small dam with a channel which is not working properly at this time. The water take over all the low parts of the land inside the town and it occupies remarkable territory extensions. There are many flooded areas inside the town. The flood magnitude of the areas depends on the bench marks of the land. There are areas in which floods persist due to the accumulation of completely stagnated waters that can’t pass through. The little slope of the evacuation courses has a lot of influence in the flood persistence. A bridge is being built to allow the waters pass through the canal until the other dam. Both dams and interconnection canals need to be repaired and maintained to fulfill their functions.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 107
Northern Regions. Flood Risk Management Plan 2011
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Northern Regions. Flood Risk Management Plan 2011
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Northern Regions. Flood Risk Management Plan 2011
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Northern Regions. Flood Risk Management Plan 2011
ONGWEDIVA TOWN FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 111 Northern Regions. Flood Risk Management Plan 2011
4.3.2.3- Ongwediva Town
4.3.2.3.1- General Characterization Ongwediva Town is situated in the Oshana Region, less than 6 Km away from Oshakati, the Regional Capital. The Town commonage covers an area of about 4104, 2896 hectares. It has an overall population of 27 000 people of which 3 500 live in the informal area of the town. Town boundaries: The existing town boundaries cover a total area of 4104 hectares, although all the land is not suitable for development, considering that several parts (1747.50 hectares) are low-lying areas (oshanas), representing the 42.50 % of the whole proclaimed area. The existing township (developed land) covers 1135 hectares, while 76 hectares (7.00 %) are usually affected by floods during the rainy season. There is a proposed extension for future development in the north part of the urban zone, covering a total area of 4809 hectares, with more potential in suitable land for development, due to the prevalence of higher lands (3866 hectares, which constitutes an 80.00 %). Residential areas: House construction is currently the most active economic activity in Ongwediva. It contributes 75% of the Council’s total income yearly. There is high demand of modern houses in Ongwediva. Currently there are approximately 4 000 people living in the informal area within the Town Council’s commonage. Social services: Ongwediva offers all essential professional services to make it the service hub of northern Namibia and in particular, creates investment opportunities for: ! Private hospital ! Research institutions ! Private and public educational institutions ! Professional services such as Architects, Engineers, Quantity Surveyors, Medical Doctors, Auditors, Lawyers, Estate Agents, etc. ! Financial institutions and banks ! Non Governmental Organisations for providing business services. Ongwediva has the highest concentration of educational facilities in Northern Namibia. Currently more than 10000 Learners get their education at the various schools and colleges in Ongwediva. Ongwediva has the only Teachers’ Training College, the only Vocational Training Centre and the only School for Disabled Persons in Northern Namibia. At the same time, there are a number of commercial enterprises and small workshops in Ongwediva. The main shops are wholesalers, super markets, general dealers, and dry cleaners while the majority of workshops are garages, services stations, brick making factory and cloth making enterprises as well as Motel offering bed and breakfast. Ongwediva
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 112
Northern Regions. Flood Risk Management Plan 2011 accommodate the Ongwediva Annual Trade Fair, which eventually take place every year at the modern Ongwediva Trade Centre. There are also office facilities in Town accommodating big institutions like Office of the President, NORED [PTY] LTD, Africon, Fenssinger Consulting Engineer, NamPower, NaTis, etc. Technical services: Ongwediva is the only town in Northern Namibia that has been properly planned and surveyed. All the formal development is provided with modern services – reticulated water, water borne sewage system, electricity, telephones and roads. All the properties in the town (formal and informal) are accessible through all weather gravel roads. All formal houses are served with electrical while the power authority can connect consumers who require power in town any time they pay the required connection fees.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 113
Northern Regions. Flood Risk Management Plan 2011
4.3.2.3.2- Situation Analysis The majority of the affected communities in Ongwediva are informal areas. During flood events, surrounding areas are isolated due to access roads are cut off and some households area affected, especially in informal settlement located in the town’s outside edge (Sky location). Therefore the main problem is related to the lack of accessibility to surrounding areas during flood events, because of the lack of proper feasibility studies during construction (culverts and bridges). The local authorities are carrying out a relocation process of people living in informal settlements (Sky location) located in flood prone areas. At the same time, new storm water drainage systems are under construction. The town planners are working towards the identification of high lands during flood events, land acquisitions and preparation of urban plans considering new roads, subdivision and infrastructure, together with the implementation of programs to help people in housing construction (Shack Dwellers Federation, Build Together Program) and assessment in building construction. The Town Master Plan is reformulated, incorporating new approaches related to floods. At the present time problems have been presented in the Sky Bridge built in 2009. The Sky Bridge was surpassed by the waters during the floods of the 2011 (current) and one of the accesses to the bridge was destroyed. The Sky area and numerous housings in it are flooded. The town is not seriously affected by flood events, but some areas become isolated during flooding. Some new residential areas are affected due to inadequate storm water solutions. The town lands located in the southern, eastern and western parts are low lying areas. Future development should be to the northern part of the existing town lands, so a new Comprehensive Town Scheme should be prepared considering environmental issues, as well as the relationship with Oshakati town and the possibility of a future merge.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 114
Northern Regions. Flood Risk Management Plan 2011
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Northern Regions. Flood Risk Management Plan 2011
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Northern Regions. Flood Risk Management Plan 2011
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Northern Regions. Flood Risk Management Plan 2011
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OHANGWENA REGION FLOOD RISK MANAGEMENT PLAN
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 119 Northern Regions. Flood Risk Management Plan 2011
4.3.3 – OHANGWENA REGION
4.3.3.1- Regional Context
4.3.3.1.1- General Characterization Location: Ohangwena Region is situated on a flat plain and extends east to west along the Angolan border. It is bordered by the Kavango Region to the east, Oshikoto and Oshana Regions to the south and Omusati Region to the west. The size of the region is 10 703 Km2. Annual rainfall ranges from 480 mm in the west to 600 mm in the east. It has by far the highest population density in Namibia at 21.3 % people/Km2, with 99 % of the population living in rural areas. The capital town is Eenhana with a population of 3 196 inhabitants and the total region 228 284 inhabitants. Water is provided by pipelines in the densely populated areas in the west, while the population in the accesses water from boreholes and traditional hand dug wells, often more than 2.5 Km. from their homesteads. Physical features: All the region are between 1000-1 500 m. of altitude. The most predominant geological formation in this region its: Sandstone and calcrete from period tertiary to quaternary-cretaceous, sequence Post-Karoo Complexes; Group Kalahari; + - 65 million years. Ohagnwena lies in what is called the Owambo Basin. For the past 70 million years, the Ownabo Basin has been filling up with sand, silt and clay washed and blown in from the higher ground. The remains of the large lakes now lie buried as layers of clay, from Ruacana to the Etosha Pan and beyond (MET 2000). We currently find ourselves in a relatively dry geological period, with the present Cuvelai network of oshanas (drainages channels) being the only remaining drainage system bringing water and sedimentary deposits into Owambo Basin from higher areas in Angola. Vegetation: In the most eastern part of the region, there is predominance of Savanna, with Mopane Savanna. In the rest of the region, there is prevalence of forest savanna and woodlands. On the higher ground between the drainage channels, Kalahari sands support mopane scrub and various larger trees on an open palm and marula savannah, including Berchermia (bird plum), marula, jackal bery, fig, Euclea (gwarri), and mopane (MET 2000; RDP 2000).These raised areas potential for crops production is considered to be higher than that of the sandy soils of the Eastern Kalahari Wodlands wish are less able to retain water, and they support much of the crop production in this part of Ohangwena Region. Climate: The average rainfall in Ohangwena ranges between 400 mm- 500 mm, with a frequency of rainfall of 30 – 50 days with rain. The rainfall variability (average deviation as % of annual average) is 35 -40 %. The seasonal distribution of rainfall is from October to March with an annual average of 80 – 90 %. The length of rain season is 4 – 5 months considering
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 120
Northern Regions. Flood Risk Management Plan 2011 the number of months per year with more than 50 mm. of rain. Size of the Region: The region covers a total area of 10 703 km2 (1.30 % of the total land area of Namibia) Population: The region is populated by 228 384 inhabitants (12.5 % of Namibia’s total population), with a density of 21.3 people per km2, although the highest densities are in the western part of the region, ranging from 40 to more 100 people per km2. Households: The population resides in 35 958 households, with an average size of 6.3 people per household. Administrative structure: The region is divided into 11 constituencies (Eenhana, Endola, Engela, Epembe, Ohangwena, Okongo, Omundaungilo, Ondobe, Ongenga, Oshikango and Omulonga). The administrative capital of the region is the town of Eenhana, although the region’s most important commercial and business development is taking place in the town of Helao Nafidi, which is a strong motivation for residents in rural zones to migrate and settle in surrounding areas.
Settlement patterns: The vast majority of the population in Ohangwena region lives in rural areas. The human settlement system is classified as follows: Towns: 2 (Eenhana, Helao Nafidi) Settlement areas: 3 (Okongo, Ongenga, Omungwelume) The rest of the region’s population resides in a scattered way in rural areas (homesteads, isolated houses, etc.). Population and households’ distribution per Constituencies Constituency Population Households Average size Eenhana 18 690 2 995 6.1 Endola 24 804 4 079 6.1 Engela 21 832 3 588 5.9 Epembe 14 860 2 264 6.6 Ohangwena 17 887 2 837 6.2 Okongo 21 551 3 329 6.4 Omundaungilo 8 115 1 094 7.4 Ondobe 22 253 3 342 6.6 Ongenga 21 706 3 498 6.2 Oshikango 25 221 3 859 6.5 Omulonga 31 465 5 073 6.2 Total 228 384 35 958 6.3
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4.3.3.1.2- Situation Analysis The Region is affected seriously by floods, especially in the western part of the territory, due to the presence of a large number of oshanas associated to the Cuvelai basin. At the same time, the impact of heavy rainfall is very important in the rural areas. The most affected areas in the region are the constituencies of Endola, Ondobe, Omulonga, Engela, Ongenga, Oshikango, Eenhana and Ohangwena where there are many places practically isolated, all surrounded by overflowed oshanas as results of heavy rainfall both in the region and southern Angola. The natural causes that aggravated the vulnerability of the region are a very flat topography that makes water slow-flowing and watercourses expand into wide areas and the nature of soils (sand-clay mixture) and the probable existence of a not to deep underground waterproof layer makes natural infiltration process very slow. The events highly affect several traditional homesteads and, thus, negatively affecting communal livelihoods. The vulnerability to floods is very high, due to the presence of disperse population and human settlements in flood prone areas, which have to be evacuated to relocation camps during the occurrence of flood events. At the same time, culverts and bridges are under-dimensioned and miss-leveled and there are several inappropriate excavation works too close to the roads to obtain construction materials Some social services like clinics (Ondobe, Endola) and shools (Ondobe, Epembe) are affected, while the road infrastructure is damaged is several areas: Ondobe – Oshigambo road, Engela – Ongenga road, Okanghudi – Onamunhama gravel road, Ongenga – Endola road (via Oshimwanku), Endola – Okatana road, Eenhana – Onhuno road, Omungwelume – Oshakati tarred road, Omafo – Ondobe gravel road and Omafo – Okalongo road.
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In summary, the major problems detected in the Ohangwena Region are: 1. Areas foreseen for future development in urban master plans have been flooded. Territorial development plans lacks an adequate settlement system perspective. 2. Recurrent situation of houses, service facilities and infrastructure placed in flood-prone areas or even inside the oshanas, despite the urban plans provisions and regulations (Omafo,Engela, Endola, Okatope and Ouwa). 3. Under-dimensioned and miss-leveled culverts unable to evacuate the overflowing waters: (Engela-Ongenga road, Eenhana-Omafo over railroad Namibia-Angola, Onuno-Engela, Okatana-Endola, Engela-Omafo by Engela Central Hospital, Omafo- Ohangwena Km 3.6, Onuno-Okatope Km 14, Ouwa Ville-Eenhana Kms 4.5, 12.9 and 19.2, Engela-Okambebe Kms 3.3 to 8.2 (Ohaingu Ville), Kms 10 to 11.4 (Shanalumuno settlement), Kms 12.6 to 13.6 ( Katemba Ville), Kms 17.8 to 18.4(Ongenga Villa), Kms 22 to 25.5, km 27 (Omungwelume) and Km 34 (Okambebe). 4. Extraction of construction materials on the sides of the roads, affecting its stability and allowing water stagnation:(Roads: Omafo-Onuno, Engela-Omafo Km 1.7, Ohangwena-Onunu Km 11.2, Nawa settlement, Ondobe entrance, Ouwa Ville, Ouwa Ville-Eenhana Km 9.1, 13.9 and 19.2, Engela-Okambebe Km 18.9 and 27 (Omungwelume), Road to Eenhana Secondary School). 5. Insufficient drainage solutions that results in water stagnation in low-lying areas: (Okatoke secondary school, Ongenga, Ohaingu km8.2, Engela-Okambebe km18.9 and Eenhana broadcasting towers, Oshikango settlement, Eenhana electric connection field, Eenhana- Onanhoke km1).
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RISK MAP PROPOSAL High Risk Zone: Western part of the Region, predominance of oshanas, high concentration of population (74 % of the Region’s total population). Comprises Ongenga, Engela, Endola, Ohangwena, Oshikango, Ondobe and Omulonga constituencies. Moderate Risk Zone: Central part of the Region (includes Eenhana, Omundaungilo and Epembe constituencies). High level of underground water, low population density, low lying areas within Eenhana town borders. Low Risk Zone: Eastern part of the Region (Okongo constituency). Higher lands, low population density.
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HELAO NAFIDI TOWN FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 125 Northern Regions. Flood Risk Management Plan 2011
4.3.3.2- Helao Nafidi Town
4.3.3.2.1- General Characterization Helao Nafidi is a town in Ohangwena Region in northern Namibia at the border to Angola. It was established in 2004 as an amalgamation of several villages and settlements along the main road between Oshikango and Ohangwena, which are both also part of the town. Helao Nafidi has 43,000 inhabitants. There are three electoral constituencies in Helao Nafidi: Oshikango, Ohangwena and Engela constituencies. The town is separated into four urban areas: Oshikango in the north, bisected by the Namibian–Angolan border, Engela – Omafo and Ohangwena in the central area and Onhuno south of it, with settlements and villages in the agricultural area between them. Oshikango suburb: The most important urban area is Oshikango, a suburb located in the northern zone and a border post to Angola. Since 2004 it is part of the town of Helao Nafidi. It is the district capital of the Oshikango Constituency. Oshikango is estimated to having grown from a tiny cluster of shebeens around an open market into a thriving boomtown with around 5,000 to 8,000 inhabitants over a period of 10 years. After Namibian independence the settlement, along with many others in the area was proclaimed a village in 1996 in order to increase border trade. The border post between Namibia and Angola has brought business opportunities to Oshikango and the surrounding area. With the help of the European Union an Export Processing Zone was established here, consisting of 14 warehouses. In mid 2005, the second stage of the new Northern Railway began construction to Oshikango from Oshivelo. By mid-2006, it had reached Ondangwa. In 2008, a short extension across the border was proposed to bypass the congested border post. Engela – Omafo suburb: Combination of two former townships. There is an intense business/commercial development in the intersection of the main roads (Ohangwena – Oshikango and Engela – Outapi). A major oshana divides the urban area. A new bridge was recently finished as well as a bypass over the railways. Ohangwena suburb: Most of the development is taken place along the main road, although new residential extensions have been planned on the east side. It is important to highlight the presence of oshana in the central area of the town, affecting existing buildings (commercial, business, and houses) as well as the existing road.
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Onhuno: It is the less developed urban area within the town. There is a prevalence of residential and business buildings, mostly along the Ondangwa – Oshikango main road as well as to the access road to Eenhana (capital of the region), while similar developments have already been planned on the east side. The eastern border is defined by an oshana. The electrical substation that serves the whole Helao Nafidi town is located in this area. There is a primary school outside town boundaries. Town boundaries: The town of Helao Nafidi has a unique attribute due to the fact that it is made of several urban and rural areas, with strong differences among them. The four urban zones are clearly bordered, isolated within a huge geographical area and no plan is already prepared in order to foresee the future structure of the whole town. Use and occupation of the land: Due to the especial condition of the town, there is a prevalence of vacant land, mostly occupied by traditional houses within strong rural surroundings. The urban areas are small in comparison to the total area of the town. The most relevant existing land uses are commercial/business along the main road from Ohangwena to Oshikango, with high incidence in the Oshikango area; residential, concentrated in the urban suburbs and scattered in the “rural” parts of the town. Other uses are social services (hospital in Engela, clinic and secondary school in Ohangwena, as well as several primary schools), public open spaces (mostly in flood prone areas)
4.3.3.2.2- Situation Analysis The area of Helao Nafidi, located in the middle of several oshanas, is very affected by floods during the rainy season. The town is separated into four urban areas: Oshikango in the north, bisected by the Namibian–Angolan border, Engela – Omafo and Ohangwena in the central area and Onhuno south of it, with settlements and villages in the agricultural area between them. The most affected areas are located in Engela, Ohangwena and Oshikango suburbs, as well as in some “rural” surrounding areas. In Engela, the main problem is related to the presence of a large oshana, which when overflowed covers the Omafo – Okalongo road, cutting off the access to Engela District Hospital from the rest of the town. The lack of proper infrastructure to allow the free flow of water coming through an oshana that cross the urban area and the presence of several buildings in the main water course area the main reasons why the Ohangwena settlement is almost totally affected by floods. Similar situation is present in the Oshikango suburb, aggravated by uncontrolled urban development, which has blocked natural water ways. In order to mitigate these affectations, some partial solutions have been constructed without an integrated approach that takes into consideration the whole urban area.
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Northern Regions. Flood Risk Management Plan 2011
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Northern Regions. Flood Risk Management Plan 2011
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Northern Regions. Flood Risk Management Plan 2011
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Northern Regions. Flood Risk Management Plan 2011
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Northern Regions. Flood Risk Management Plan 2011
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Northern Regions. Flood Risk Management Plan 2011
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Northern Regions. Flood Risk Management Plan 2011
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OMUSATI REGION FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 136 Northern Regions. Flood Risk Management Plan 2011
4.3.4- OMUSATI REGION
4.3.4.1- Regional Context
4.3.4.1.1- General Characterization Location: Omusati Region is situated in the north central part of Namibia, bordering Angola on the North, Ohangwena and Oshana regions on the East and Kunene region on the south and West. Physical features: The region is a semi-arid, flat area, with one permanent river, the Kunene, on its north western border with Angola. The area is characterized by thousands of shallow drainage channels or oshanas which funnel from Cuvelai basin in Angola towards the Etosha Pan. The Cuvelai system is characterized by shallow depressions or oshanas which fill up with surface water during the rainy season. The Cuvelai originates in Angola with its catchments falling between the Kunene and the Kavango " Okavango drainage system. The system is fed by a number of rivers, some of which have their headwaters as far north as the Encoco highlands in Angola, Regions of Namibia which receive on average over 800 mm of rain a year. As these seasonal waters move southward, the land becomes flatter and the rivers and channels meandering towards the Namibia border feed into each other at some places and part ways at others, forming a massive inland delta. These seasonal flows provide fishing grounds, renew pasture and recharge ground water supplies. The oshanas in the Omusati region are much boarder and flatter than in the Oshana and Oshikoto regions are much channels closer to each other. Most channels come together further south in a few main watercourses and eventually flow into the Etosha Pan via the Ekuma River. Vegetation: Vegetation in Omusati region is largely influenced by soils and water. However, the region has a large variety of vegetation type. Vegetation in the Cuvelai part of the region ranges from mopane (fruit tree) to mopane shrub and low trees on oshanas and limited Cuvelai palms and fruit trees on loamy sands. In the remainder of the region one mainly finds the western sand plains interspersed with Mopane " Combretum savanna, western mopane " pan mosaic and mixed broadleaf woodlands on red dolomite sands at the edges in the Ruacana area and at the extreme south western corner of the region. Climate: Average rainfall in the Omusati region ranges between 300 mm- 500 mm, with a frequency of 30 – 50 days with rain (annual average) and a rainfall variability of 35 – 50 % (average deviation of annual average). The seasonal distribution of rainfall shows that the rainfalls for the period October - March comprise the 80-90 % of annual average. The length of rain season is between 2 – 5 months, considering the number of months per year with more than 50 mm. of rain.
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Size of the Region: The region covers a total area of 26 537 km2 (3.22 % of the total land area of Namibia) Population: The region is populated by 228 842 inhabitants (12.5 % of Namibia’s total population), with a density of 8.6 people per km2, although population density in the Cuvelai area (north) is much higher than in the Sandveld area to the south and west, ranking amongst the most densely populated areas in the country. Households: The population resides in 38 202 households, with an average size of 5.9 people per household. Administrative structure: The region is divided into 12 constituencies (Anamulenge, Elim, Etayi, Ogongo, Okahao, Okalongo, Onesi, Oshikuku, Otamanzi, Outapi, Ruacana and Tsandi). The administrative capital of the region is the town of Outapi, which has witnessed a moderate urban development in recent years, a strong motivation for residents in rural zones to migrate and settle in surrounding areas. Settlement patterns: The vast majority of the population in Omusati region lives in rural areas. The human settlement system is classified as follows: Towns: 3 (Outapi, Okahao, Oshikuku, Ruacana) Settlements: 4 (Okalongo, Ogongo, Tsandi, Onesi) The rest of the region’s population resides in a scattered way in rural areas (homesteads, isolated houses, etc.).
Constituencies in Omusati Region
Population and households’ distribution per Constituencies (Source: 2001 Census) Constituency Population Households Average size Anamulenge 12 617 1 870 6.7 Elim 10 850 1 781 6.1 Etayi 35 130 5 746 6.1 Ogongo 19 611 3 371 5.8 Okahao 17 751 3 244 5.4 Okalongo 28 719 4 213 6.8 Onesi 12 995 2 227 5.8 Oshikuku 8 299 1 357 5.9 Otamanzi 13 121 2 319 5.6 Outapi 31 496 5 049 6.1 Ruacana 11 204 2 217 4.8 Tsandi 27 049 4 808 5.6 Total 228 842 38 202 5.9
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General indicators (Source: Omusati Regional Poverty Profile. October 2005 – February 2006): ! Human poverty index: Omusati ranked as the seventh poorest region in the country with a HPI of 27.1 %, suggesting that 27.1 % of the population was classified as poor. (UNDP 2000). ! Infant mortality rate: 86 out of 1000 children ! Food security status: In the year 2000, 9 % of children under the age of five years were under weight in the Omusati region. ! Life expectancy: Female – 50.5 years Male – 46.6 years ! Health services: Omusati region is served by a total of five hospitals, situated at Outapi, Okahao, Oshikuku, Tsandi and Okalongo. There are a further 6 health centers, 33 clinics and 76 outreach. In 2001, the region had a total of 550 hospital beds at its disposal. ! Educational facilities: There are 265 schools in Omusati region, comprising161 primary schools, 86 combined schools and 18 secondary schools. ! Water: Eighty-three per cent of the population in Omusati region has access to safe water, either through piped water in or outside the house (33.33 %), a public pipe (46.20 %) or a safe borehole (3.0 %). Seventy nine per cent of the population had access to water within 1 km. ! Sanitation: Access to acceptable sanitation is unsatisfactory in the region. Only 3.3 % of the population had access either to a private flush toilet or a shared one, while 83 % were making use of the bush. In 7.9 % garbage was regularly collected and in 15.5 % this happened irregularly. 23.7 % of the households disposed of their garbage in rubbish pits and 19 % dumped it along the roadside. ! Economic activities: In Omusati region around 46 % of all households incomes are from farming activities, a combination of factors such as unreliable rainfall, moderate soils, low crop production inputs and low levels of agricultural technologies often result in low yields of coarse grains. With low yields, several households are unable to meet most of their basic needs and thus engage in a range of non farming activities for additional incomes. Common sources of income include sale of livestock, weaving traditional handcrafts, selling grass, roots, tubers and fruits from the veldt, sale of amarula oils, brewing local beer, and trading. Pensions, salaries and government grants are also sources of incomes for some categories of people. ! Unemployment rate: Unemployment in Omusati was estimated at 35.6 %, which imply that the dependency ratio is relatively high.
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4.3.4.1.2- Situation Analysis The Region is almost entirely associated to the Cuvelai basin. During rain seasons, the Cuvelai evacuates most of its excessive volume of water through the oshanas system that covers a large portion of the territory. This natural process has increased its intensity in recent years, aggravating damages on population, infrastructure and crop fields. Most of the population is concentrated in the north part of the Region, where the most affected areas are located, being the constituency of Etayi the most seriously affected (2011). More than 1000 households are affected, as well as several social services like clinics (Okalongo, Etayi, Tsandi, Ogongo) and schools (Okalongo, Etayi, Ogongo, Elim). Crop fields and mahangu stocks are also severely affected. Most of the road infrastructure is damaged, especially the Tsandi – Onesi road, full of potholes, very bumpy and slippery; Onesi – Epalela road, with sand over some culverts washed away by rain; Outonyo – Onheleiwa and Odimbwa – Okambebe roads, washed away in several parts; Okahao – Etilyasa road, which was completely washed away at one place. There is no way to access to Etayi and Otamanzi by road. The road network in the region is one of the main causes of the high damages produced by floods, due to the alteration of the natural water ways is several areas. The main aspects affecting the road vulnerability are the insufficient number of culverts and bridges, small capacity of existing and new culverts. The current situation is very unfavorable since the flood waters are mixed with waste waters and affected people are living in a contaminated environment exposed to diseases and dangerous water animals. Numerous services facilities are closed including schools, some properties have been protected from the flood by means of constructing isolating walls and up-leveling ground floors but obstructing the water flows while doing so, some people have relocated themselves to higher grounds into improvised precarious houses while others remain in their flooded homes.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 140 Northern Regions. Flood Risk Management Plan 2011
RISK MAP High Risk Zone: northern part of the Region (north of Oshakati – Ruacana road). Onesi town. Moderate Risk Zone: Area between Oshakati – Ruacana road and Okahao – Tsandi – Onesi road and Ruacana – Opuwo road. Low Risk Zone: Rest of the Region.
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OUTAPI TOWN FLOOD RISK MANAGEMENT PLAN
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 142 Northern Regions. Flood Risk Management Plan 2011
4.3.4.2- Outapi Town
4.3.4.2.1- General Characterization Outapi town is located in the north-central part of the region of Omusati. The town has a privileged location in the Oshakati-Ruacana road, linking East- West of the region as well as connected to the roads leading to the northern areas (Okalongo road) and to the South (Tsandi-Okahao road). According to the proclaimed town boundaries, the size of the existing township is 653 hectares, while the extension boundary covers a total area of 3586 hectares, so 2933 hectares are not developed. Outapi is the capital of Omusati region and the center of the Outapi constituency. The town is the seat of the Offices of the Omusati Regional Council, Outapi Town Council and Outapi Constituency (under construction). There are also several government institutions. The importance of the town within the region has generated a high concentration of commercial and business activities, mostly along the main roads. The population of Outapi is 8 089 inhabitants. The town is between 1000-1500 m. of altitude. The area of the Outapi town is characterized by higher zones at the northwest of the town (Tobias Hanyenco and Onhimbu) the first area is formalized for planning and the second one is a new area for developing with housing already existing. At the northeast of the town is located Kasikili area surrounding at north by oshanas as prone floods areas. The central part of the town (traditional area) is also located in a higher zone despite of the presence of some low-lying areas prone to floods (close to MTC tower, near the main road Oshakati-Ruacana). The area behind the open market is also a low-lying area. The water canal that runs from Ruacana to Oshakati is located at the southwest and south of the town, and constitutes a physical threshold for the future developing of Outapi. The area at the south of the canal is a large low-lying area prone to floods. Nevertheless, an informal settlement called Oukwa has being developed without any technical infrastructure. In general the difference of altitude in the town as comparison between the north and south part not exceed almost 3.5 m. Town boundaries: Outapi is developed mostly within the boundary officially approved when the town was proclaimed in the year 1997. This boundary is defined mostly by infrastructure elements: The high voltage power lines in the north, the Ruacana-Oshakati water canal in the south, and the roads to Okalongo and Osakati in the east. Later, an extension of the on boundary was approved, including the remainder of the farm Outapi Town lands No 860. This extension allowed the incorporation of some neighboring areas to town jurisdiction (Kasikili, Tobias Hainyeko and Oukwa, the two first with planning proposals already prepared) as well as the sewerage pond and the newly constructed
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Northern Regions. Flood Risk Management Plan 2011 airfield. Use and occupation of the land: The existing land use shows a high potential of vacant areas that can accommodate the future development. The land located among the main road is occupied mostly by commercial, business and administrative buildings. To evaluate the land use and occupation is possible to identify three main areas within the existing town boundary: Area 1: North of Oshakati-Ruacana road. Area 2: South of Oshakati-Ruacana road and west of Outapi-Tsandi-Okajao road. Area 3: South of Oshakati-Ruacana road and east of OUTAPI-Tsandi-Okajao road. Area 1: Partially occupied. Insufficient coverage by technical infrastructure (water supply, roads, sewerage). Rural characteristic: Dispersion, lack of a proper urban ordering (except in NHE area). Mix of business and housing. Area 2: Partially occupied. Adequate coverage by infrastructure (water supply, roads, sewerage). Semi-urban characteristics, semi- compacts. Potential in vacant lands. Adequate urban ordering. Social services: schools, government buildings: Office of Town Council, Office of Regional Council. Concentration of most of social services and business. Area 3: Prevalence of vacant land (planned and unplanned). Mostly business and commercial buildings, especially along main road. Social services: Hospital. Adequate coverage (existing buildings). Residential areas: The residential areas are clearly identified, one planned area in the central part of the town, with potential for future increase in the number of houses. In the north-western part there is another planned area where a government funding programme is developed (Namibia Housing Enterprise). There are several household scattered thought the town, especially north of the Okakwa and Onhimbu areas. Far in the north and crossing town boundaries there is an informal residential development without planning (Tobias Hainyeko). In the south part, out of the existing town boundaries (but within the Scheme Boundary) there is another informal settlement (Oukwa) connected through the Tsandi road. Outapi town has five existing residential areas, with different characteristics: Area 1: Contains Outapi proper, Extension 1 and Extension 2. It’s the most consolidated and compact residential zone, served by infrastructure, housing in good technical conditions, with planned urban development in plots about 300 m2 in size. Easy accessibility to main social services (hospital, schools) and strongly related to the main commercial center of the town. Potential in vacant lands for new insertions and possible
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Northern Regions. Flood Risk Management Plan 2011 increase of the size if extension 3 is developed (near Namwater). Semi-urban characteristics (gravel roads). Area 2: Contains Namibia Housing Enterprise houses: Located in the north of the Oshakati- Ruacana road, has a total potential of more 100 houses. Area underdevelopment. Served by infrastructure. Houses in good technical conditions, planned urban development. Difficult accessibility to social services and town center, due to distance and presence of the Oshakati-Ruacana road. High potential in vacant lands. Semi-rural characteristics. Area 3: Tobias Hainyeko and Onhimbu areas. Located in the north part of the town, close to town border. These are two different areas, but share similar characteristics. Dispersion. Rural characteristics, prevalence of houses in bad technical conditions (shacks). Insufficient infrastructure network (roads, water, sewerage, drainage) Process of formalization- extension-. Difficult accessibility to social services and town center. Area 4: Kasikili area. Located at he north of Oshakati-Ruacana road and east of Outapi- Okalongo road, is a planned area, with an starting development, with the prevalence of housing plots underdevelopment in the north of a group of business. Rural characteristics, dispersion. Lack of infrastructure, deficient accessibility to social services and town center. Vacant lands. Area 5: Oukwa area. Located in the north of the town, in the Outapi-Tsandi road, out of the initial proclaimed town boundary, but within the extension boundary. Isolated of the town, rural characteristics, houses in bad technical conditions, no infrastructure, unplanned area, informal settlement. Difficult accessibility to social services and town center. Social services: Outapi District Hospital., Secondary School, Special School, Primary School (private), Primary School (public), Anamulenge district, 3 Km. from the town. Technical services Water Supply: Outapi receives a supply of potable water from the Namwater purification plant located to the west of the town. The plant consists of a batch plant and a package plant. The package plant was constructed to replace the batch plant. The batch plant is no longer operational but remains un-demolished. Raw water is supplied to the plant from the nearby Olushandja-Ogongo canal. The water flows into deep wells or is stored in a 70 000 m3 storage dam located at the plant. From there the water goes to the purification plant. It is purified and pumped into a ground level reservoir. From the reservoir the water is pumped to the Ombalantu Rural Water Supply Project and to an elevated reservoir for municipal supply to Outapi, Onakayate and Anamulenge. Drainage: No drainage system is in place. There is a Master Plan on urban drainage, but no implemented due to lack of funds. Sewerage: About 31 percent of the households in the urban areas use flush toilet and 20 percent use the bush. Outapi’s sewer system consists of a pipe network and manholes conveying wet waste under gravity to various pump stations located in the town. The pump station, pump the water via a piped network to oxidation ponds to the south of the town. There are also a number of pit latrines in the town, located mostly in the areas of the town that do not have wet sanitation.
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Communication: The town has accessibility to selected services/facilities. These include television, radio, newspaper, telephone and computer. The radio is the most accessible services/facilities, with 82.7 % en urban areas. Electricity: The 100 percent of the town is covered by the national electricity system. The power lines arrive to the town to a substation located in the road to Okalongo by NAMPOWER, from there the town is serviced by NORED.
4.3.4.2.2- Situation Analysis The flooding problem in Outapi can be grouped into two categories, namely ! Flooding due to local rainfall inside the town area and ! Flooding from adjacent oshanas. ! Other problems: Package plant problems affecting storm water. ! Sludge room sedimentation tank: There is a significant amount of dry sludge on the ground and concrete around the package plant. Automatic desludging does not remove all sludge so sludge build up at the bottom of the hooper-shaped tanks. The access covers and pipe work are removed at the bottom of the tanks (below the lamella packs) and the sludge is jetted out. The lamella packs cover the whole bottom of the tanks (no access from top) and the de-sludging pipes are goose- necked, therefore this is the only way to remove the sludge. This sludge is unhygienic and rainfall runoff carries it into the nearby oshanas where it may come into contact with people. ! Sledging drying beds: The sledging drying beds are not frequently cleaned. The beds are therefore filled with sludge and overgrown with reeds. This causes the retention time of beds to be small and the water flows out as fast as it flows in. Also, the recycle pump and level control are out of operation and no water is being recycled to the plant. This explains why the unlined ponds are flowing into the oshanas. The raw sludge flows to nearby watercourses polluting the natural environment. In addition, a joint in the concrete collection channel on the drying beds has opened, allowing water to flow trough. ! Elevated tank: The plastic tanks that have replaced the original steel tanks as an elevated tower for distribution are exposed to the sun and have started to crack severely, specifically at the inlet and outlet connections. Two of the six tanks are out of use. Contamination of the town drinking water can occur by rainfall and entrance to the water supply by birds, mosquitoes and other insects. Flood damage to Namwater canal: Flooding of the oshanas around Outapi can cause damage to the Namwater canal. Beaches of the canal allow oshanas water to flow into the canal and in turn to the purification plant.
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Problems due to flooding. ! Damaged pipelines: It is reported that the floods incur damaged to the scheme pipelines by eroding pipe cover and causing breakages to the supply pipes. While the pips are under water it is very difficult to carry out the necessary repairs so this often results in the managers of the scheme shutting down certain section to prohibit the waste of water. Naturally the effect of this is that certain beneficiaries of the scheme are left without treated potable water until such time as the pipes can be repaired. ! Damage to water points: The tanks and tank stands are sometime damaged or washed away during floods event, requiring repair or replacement. ! Inundated water meters: The water meters at the water points are often under water. The community can therefore not track how much water they are using and Namwater is unable to read the meters for cost recovery. Sewer reticulation. ! Brick manhole: Some manholes in the northwest of the town are constructed by brickwork instead of the standard concrete. The brick walls allow groundwater to infiltrate into the manholes and therefore into the larger reticulation system. ! Manhole and rooding eye levels in flooded areas: In low-laying areas susceptible to standing water, the manhole covers and rooding eyes are inundated by water allowing water to seep into the manholes and into the reticulation system. In some instances where manhole covers and rooding eyes are damaged, the flow of water into the system is substantial. ! Pipe leakages: The pipe work in the reticulation system may allow groundwater to seep into the system due to breakages in some places and inefficient sealing in others. The infiltration of the storm water into sewer reticulation system results in large amounts of water gravitating to the sewer pump station which in turn cause the pumps in the stations to pump continuously to the oxidation ponds. The effect of this is that the oxidation ponds receive higher inflows of waste water (combined with storm water) than their capacities can handle and overflow occurs into the surrounding oshanas. The consequence of this overflow is that the earth walls of the ponds are eroded, further reducing the capacity of the ponds and exacerbating the overflow situation. Ultimately, the oshanas that are used by downstream communities for bathing, washing, fishing and sometimes drinking, receive raw water which can cause serious hazards for those communities. Pump Stations: The pumps in the pump stations are required to pump for long periods, often non-stop, to prevent the sumps of the stations from overflowing. This workload exceeds the pump’s design capacity and failures of the pump mechanism occur. Repair or replacement of the pumps is costly and downtime of the pumps also means that sections of the sewer system are not operational. The filling of the entire sewer reticulation system due to infiltration and the inability of the pumps to remove the excess flow has also resulted in sewer water overflowing into houses and housing premises. This creates
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Northern Regions. Flood Risk Management Plan 2011 extremely unsanitary conditions for the community and can contribute to spread of diseases such as diarrhea. Pit latrines: Pit latrines by their nature contain raw waste in excavated pits. If these latrines are located in low-lying areas, there is a anger that the pits become flooded with water during periods of high rainfall and that this water mixed with the raw waste overflows and comes into contact with the human population. There are a number of pit latrines to the north of the town that are situated in low-lying areas. Further investigation should be undertaken to determine if these latrines do cause a health hazard in that area due to flooding. Storm water and roads: The majority of the road network in Outapi consists of un-surfaced roads. There are two surfaced roads namely the national road leading to Ruacana and Oshakati to the east and east respectively and the road leading to Tsandi. The road in Outapi contributes significantly to standing water from rainfall in the town. There is a lack of adequate storm water infrastructure on these roads, and in some instances the roads do not have any infrastructure to allow water to drain away from residential areas, effectively damming the rainwater that falls in these areas. The existing storm water infrastructure in the road network consists of a combination of drifts and culvert. During the recent heavy rainfall period in Outapi were identified damaged that occurred to road infrastructure in Outapi. The road leading to the oxidation ponds was overtopped by the oshanas water in the vicinity. The road was eroded and aces to the oxidation ponds for repair and maintenance work was interrupted. The oxidation ponds themselves were in need of repair during the recent rainfall period to prevent raw waste water from escaping to the oshanas. The road through Onhimbu suffered similar damage due to local rainfall eroding the road surface and preventing access to this business district. According to this study was estimated that approximately 60 % of the un-surfaced roads in Outapi were moderately to severely damage because of recent flooding. A preliminary assessment of the situation indicated that measures to be implemented to prevent future similar damage would include raising road levels and construction of additional storm water infrastructure to allow sufficient drainage of flood water. (Lithon Project Consultants (Pty) Ltd. P0326-Report Final-091009-004.)
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OKALONGO SETTLEMENT FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 153 Northern Regions. Flood Risk Management Plan 2011
4.3.4.3 – Okalongo Settlement Area
4.3.4.3.1- General Characterization Okalongo is one of the four settlements of Omusati Region; it is the capital of the Okalongo Constituency, one of the twelve constituencies of the region, located near the border of Angola. The constituency has 28 719 inhabitants (Census 2001). The settlement of Okalongo is located along the Anamulenge-Engela gravel road, about 30 Km north-east of Outapi, the capital of the region. There is a direct access to the settlement through a tarred road from the town of Oshikuku, allowing an easy link to the Oshakati-Ruacana road, the most important one in the region. This settlement is located between 1000-1 110 m. of altitude. The traditional settlement is surrounded in the west side by a big low-laying prone area to floods with several oshanas principally in Yanadjaba area, very close to the oxidation pond of the settlement. At the north is located an area called Onandjaba for the new development of the settlement. At the south of the main road Outapi-Oshikango, near to the Lodge and the Business Complex Building is being developed some housing a schools, and business stores. This zone has certain instability in its soil for construction (arenosoil). The population of the settlement is estimated in almost 500 inhabitants. Okalongo is seat of the constituency office and traditional authority. Due to its condition to be center of the constituency and the nearness to Angola border, has made that the settlement is mostly occupied by commercial and business development, although it is important to highlight the presence of several educational institutions which are attended by many learners from different areas surrounding the settlement. Town boundaries: The settlement is developed on both sides of the Anamulenge-Engela road, including the presently occupied areas and the future development land existing. The township is subdivided into two main areas: one north area (Onandjaba) and one south area, both with potential in vacant lands. The land reserved for future development is mostly on lying low areas. Use and occupation of the land: Most of the land within township boundaries is vacant (planned and unplanned) Apart from that; there is a prevalence in social services (3 schools, one hospital) and business/commercial development. The residential use is scarce and it’s mostly located in low-laying areas (oshanas). Other uses are government institutions (Constituency Office, Traditional Authority)
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Residential areas: As mentioned above the number of houses is small, mostly scattered throughout the settlement. Some people reside inside their business. Most of the houses located within town boundaries lack of good technical conditions. They are mostly with zinc sheets, especially those ones located in the flood prone areas (oshanas), while the ones located in the north part of the settlement have better conditions, with durable materials. There is not a proper organization in the housing areas; most of the planned residential areas area vacant land, while the most of the existing houses are in areas proposed for open public spaces by the Planning Scheme. Social services: The settlement is well served by social services (hospital, schools, commercial) which are attended not only by the resident population, but also by residents of neighboring areas. There are three public schools (Primary, Junior Secondary School, and Secondary) as well as a private primary school. Most of the social services are in good conditions. The hospital has a new building, improving its capacity and services. The schools also have a good situation. The government offices are of recent construction (Constituency and Traditional Authority Offices). The police location needs to be completed with the proposed buildings and houses for its members. The private primary school is located in a flood prone area (oshanas), so it is affected during flood events. Technical services: The settlement is partially served by water supply, electricity and sewerage. The road network is not defined, due to the lack of implementation of the proposed road network by Planning Scheme. No one of the roads is tarred.
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4.3.4.3.2- Situation Analysis This settlement area is seriously affected by yearly flood events. It is the centre of an important educational complex, attended by a large number of learners from the rural areas of the northern part of the Omusati Region. There are other important service facilities such as hospital, constituency office, traditional authority office and commercial and business related buildings. A majority of the population resides in low lying areas, with provokes a high degree of damage to houses and properties during the rainy season. Floods due to an above-normal rainfall and/or high inflows in the Cuvelai Basin or the combination of both natural events are the main hazard that the settlement faces every year during the rainy season. The whole area is vulnerable to this problem, due to the presence of oshanas within the settlement boundaries and neighboring areas. Numerous houses and service facilities are affected mainly by the absence of drainage solutions as well as for being inside the oshana. Most of the houses are brick and sheet made placed on no regular urban order along dirt roads of small section. Many of the existing social and commercial services (schools, hospital and supermarkets) are surrounded by water and are accessible only through temporary pathways. In cases waste water has mixed along with flood waters, a school had to be closed due to health hazard. Those who cannot afford the direct water supply use public taps or the very contaminated water from the oshana and with regards to electricity, it’s the same provided to those able to afford it while there’s no solution to keep waste water from mixing with flooded waters. Main roads are those from Engela to Outapi and from Oshikuku as well as a gravel road across town S-W also from Oshikuku, other sections of roads are cut off leaving houses and services facilities with no access.
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OSHIKUKU TOWN FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 161 Northern Regions. Flood Risk Management Plan 2011
4.3.4.4 – Oshikuku Town
4.3.4.4.1- General Characterization Oshikuku is a town located in the Northeastern part of the Omusati Region, about 60 kilometers east of the town of Outapi (capital of the region) and 30 kilometers from the town of Oshakati (capital of Oshana Region). The town is easy accessible through the Oshakati-Ruacana road. It is the district capital of Oshikuku Constituency (8299 inhabitants). The population of the town area is estimated in 2800 inhabitants. Due to its condition of town is the seat of the Constituency and Town Council Offices. There is a rapid population growth, due to the privileged location of the town, in the Oshakati-Ruacana road, as well as to the proximity to Oshakati, the most important urban center of the north of Namibia. Also has an intense commercial/business development along main roads. This town is located between 1000 - 1100 meters of altitude. It is surrounded on the north, west and east by oshanas as low-laying areas prone to floods. This town is developed at the south of the main road Oshakati - Ruacana and water canal. Higher lands are located on the extreme south of the town occupied by the hospital, cemetery and a future development area, outside the existing town boundaries, named Makalani Palms. Town boundaries: The town is subdivided into two major areas, due to the presence of the Oshakati-Ruacana road that divides the town, so the town lands boundaries are sectioned in two areas (north and south). The south part is the most compact and organized than the north part (Okapya area). The boundaries of the existing town lands are, on the north: Okapya area; east: Ruacana – Oshakati water canal; south: hospital border and west: road to Elim. For future development, the town has an extension boundary, with some areas on the north, but the most of the reserved land is located on the south (remainders of Oshikuku town lands No 991). Use and occupation of the land: Within existing town boundaries it is possible to identify different land uses with prevalence of the vacant areas (planned and unplanned), business, residential and social services. The businesses are located mostly along the Oshakati-Ruacana road, and cover most of the occupied land located north of the road (Extension 2). Residential areas are mostly in the south of the road, with a consolidated structure in the Oshikuku proper zone, while the extension 1 is still under development. In the north part outside of existing town lands boundaries, an informal settlement is located,
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Northern Regions. Flood Risk Management Plan 2011 and the residing population is upgrading the living conditions without proper planning procedures. Due to the prevalence of vacant lands both town areas can be classified as partially occupied, despite the fact that several vacant residential plots in the south part have already been acquired, so the local government is considering to open new development areas to the south of the town lands, process that will require planning proposals to allow easy accessibility to that area. Residential areas: The residential areas are located mostly on the south part of the town: Oshikuku proper and Oshikuku Extension 1. On the north side, the number of the residential units is few and most of them are part of the informal settlement located outside town boundaries. The Oshikuku Proper residential area are almost fully occupied within a formal planning structure, good technical conditions, served by infrastructure and easy accessibility to main social services. In the Extension 1 zone, the construction of new houses is under development, the number of vacant residential plots is still high in the planned areas, existing some unplanned residential areas surrounding the hospital facilities, which constitute a potential for future development. The NHE Program has 99 plots in the area, although some of the planned plots are affected due to its location in low – lying areas. Social services: Social services are located on the south of the Oshakati – Ruacana road (Nuujoma Secondary School, Combined School, Primary Scholl, Kindergarten, hospital, private clinic and private pharmacy). Their technical condition is good. Technical services Water Supply: NAMWATER provides the service to the town, through the Village Council. There is a water supply network that covers totally the south part of the town and partially the north part, where a water supply project is to be implemented in the near future. The main source of water is the Ogongo treatment plant, with two water towers in the NAMWATER facilities for its distribution to the town. Drainage: No drainage system is in place. Sewerage: The collection network covers fully the south part of the town and some part on the north; the system has 3 pump stations, the final destination of the system is an oxidation pond located on the south- west of the town, near the road to Elim. The no served population, mostly residing on the north area, use septic tanks. There is a system of oxidation
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Northern Regions. Flood Risk Management Plan 2011 ponds that served the hospital (mission), with some functional problems during flood events, contaminating rain waters, which constitute a health hazard. The area where the oxidation ponds are located is proposed for future residential development by the Oshikuku Town Planning Scheme, considering that system should be removed, connecting the hospital (Mission) to the existing sewerage system. Communication: The town is fully served. Presence of communications towers (MTC, Telecom). Electricity: The town is fully served by electricity. There is a power station owned by NORED, located on the east pat o town. Existing urban planning regulations: The Oshikuku Town Planning Scheme, 2nd Draft, prepared by Stubenrauch Planning Consultants (SPC) in September 2010 includes a set of regulations to guide the future urban development of the town.
4.3.4.4.2- Situation Analysis Oshikuku town is located between two oshanas, which are flood prone areas, affecting parts of the town due to their overflow. At the same time, the Ruacana-Oshakati water-canal presence within town boundary is another hazard, affecting neighboring areas when overflow. There are some low-laying areas within town boundaries that are affected by heavy rainwater, aggravated by the lack of a proper storm water drainage system, provoking that the rainwater stands still; affecting houses and other properties.
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OKAHAO TOWN FLOOD RISK MANAGEMENT PLAN
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4.3.4.5 – Okahao Town
4.3.4.5.1- General Characterization The Okahao town is located in the south center of the Omusati Region, about 60 km south of Outapi and 70 km west of Oshakati. The population of the town is estimated in 7 000 inhabitants. The town is located between 1000-1 100 m. of altitude and a very flat area with a difference between the higher areas from the more low-laying areas of Okahao is not affected directly by the floods due to the volume of water coming through the oshanas from the Cuvelai basin, but specifically by the heavy rain falls and the fact that the area is very flat with several flood prone areas within town boundaries, especially in the eastern part. The rainwater stands still, due to the lack of an appropriate drainage system in place to facilitate the rapid evacuation of the water. The areas located at the north of the main road Tsandi-Oshakati are in general more low-laying areas with some islands higher than the rest of the area in which are located, Namwater, Ogandjera Mission and the cemetery. At the south of this road are located higher lands with presence of the Town Council, hospital, police station and the new development housing zones of the town and also is located de traditional town. At the east part of the town is located a big area with some low-lying areas prone to floods. The Okahao town is located in the south center of the Omusati Region, about 60 km south of the Outapi town, capital of the region, and 70 km west of the Oshakati town, capital of the Oshana region. There is a good accessibility through the Outapi – Okahao road. The town is located between 1000-1 100 m. of altitude and a very flat area with a difference between the higher areas from the more low-laying areas of only 2.0 m. The areas located at the north of the main road Tsandi-Oshakati are in general more low-laying areas with some islands higher than the rest of the area in which are located, Namwater, Ogandjera Mission and the cemetery. At the south of this road are located higher lands with presence of the Town Council, hospital, police station and the new development housing zones of the town and also is located de traditional town. At the east part of the town is located a big area with irregular relief with some low-lying areas prone to floods.
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Okahao is the second most important town of the Omusati region and capital of the same name constituency. According to the 2001 Census, Okahao Constituency has a total population of 17 571 inhabitants; it is the largest one in the region. The south part of the constituency is part of the Etosha National Park. Town boundaries: The existing townlands boundaries are defined by the planned lands, although many of them are still vacant. There is an unplanned area reserved for future development outside of the existing town boundaries, considered as extension boundary (Remainder Okahao Townlands No. 989). Use and occupation of the land: Okahao town has a similar urban structure to the rest of the towns of the Omusati Region (Outapi, Oshikuku), with a main road passing through the urban area (Outapi – Oshakati road), sectioning the urban area into two main zones, one in the north side with less density and a prevalence of vacant land and other on the south side, more consolidated. Most of the land within the existing town boundaries is vacant, although the whole area has already been planned. The residential areas are located mostly on the southern part, while the business/commercial development occurs mainly along the the Ruacana – Oshakati road, and on the northern side of the town. The social services (schools, hospital) and government buildings (town Council and constituency offices) are located on the south part, although a secondary school is in the northernmost part of the town. It is relevant the identification of low lying areas within town boundaries, which are considered as Public Open Spaces by the Okahao Town Planning Scheme. Residential areas: While there are few and scattered houses in the north part of the town, the south area accommodates most of the residential development in planned zones (Okahao Proper and Extension 2) Social services: The town is well served by social services, in the health sector (hospital, private clinic and pharmacy), education sector (one combined school and two secondary schools) and several commercial buildings. There is predominance in the good technical of the buildings where those services are operating, and an expansion for new hospital facilities is now in place. Technical services Water Supply: Okahao receives a supply of potable water from Namwater. The main source is a pipeline coming from Ruacana to a damn and treatment plant located in the central area of the town. The distribution system initiates from a water tower located in the Namwater site, to a reticulated network that covers most of the occupied land on the south zone and some parts of the north zone. Drainage: No drainage system is in place. Sewerage: The town is served by a sewerage system that covers most of the urban area, consisting in a reticulated collection network and four (4) pump stations distributed throughout the town area. The final destination of the collected residuals is an oxidation pond located on the south part of the town, outside of town boundaries. Communication: The town has accessibility to all services and facilities. Electricity: The town is fully served with electricity by NORED.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 171
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4.3.4.5.2- Situation Analysis Okahao is not affected directly by the floods due to the volume of water coming through the oshanas from the Cuvelai basin, but specifically by the heavy rain falls and the fact that the area is very flat with several flood prone areas within town boundaries, especially in the eastern part. There are many houses and business located in low lying areas. The main hazard is the heavy rain falls and the fact that the area is very flat with several flood prone areas within town boundaries. The rainwater stands still, due to the lack of an appropriate storm water system in place to facilitate the rapid evacuation of the water.
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Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 173
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 174
Northern Regions. Flood Risk Management Plan 2011
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PROPOSALS FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 177 Northern Regions. Flood Risk Management Plan 2011
5.0– PROPOSALS
5.1 - GENERAL REGIONAL PROPOSALS: Planning authorities will introduce flood risk assessment as an integral and leading element of their development planning functions. The new flood risk assessment system will introduce processes for identifying flood risk and determining what flood risk assessment is required and carrying out such assessments similar to the overall system for screening and scoping. Planning authorities will ensure that development is not permitted in areas of flood risk, particularly floodplains, except where there are no suitable alternative sites available in areas at lower risk that are consistent with the objectives of proper planning and sustainable development. Where such development has to take place, the type of development has to be carefully considered and the risks should be mitigated and managed through location, layout and design of the development to reduce flood risk to an acceptable level. Because of exceptional water levels must be kept in mind so that new structures will not be built in the possible floodwater basins. When dry season begins and most of the water has gone, opened drainage routes have to be strengthened and protected from erosion. Routes, which are considered permanent solutions, have to be also enlarged so that their capacity is sufficient for future development and exceptional situations.
General Proposals For the whole territory affected by flooding, it is important to consider the following: • Floods in northern Namibia are only a part of a much bigger problem that involves neighboring countries as Angola and Zambia; therefore definitive solutions must be found at a wider scale and must include all parts concerned. • Understand floods in the Northern regions as a natural, annual and unavoidable event, considering two different strategies according to the level of development in the affected areas • Relocation of population living in flood prone areas. • Construction of small hydraulic works to collect water for its use in agricultural activities, fishing and others. • Development of small scale tolerable agricultural activities in areas where the shallow flood water remains for certain periods of time (rice fields, etc.) • Preparation of feasibility studies on potentialities for the development of other economic activities in flooded areas. • Rehabilitation of sewerage systems, including oxidation ponds, pump stations, boreholes and reticulated network.
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At the same time, it is important to identify the main actions to be implemented considering different activities, such as: Construction • Increase capacity of bridges and culverts. • Reforestation of river banks. • Construction of protection works. • Demolition of buildings located in natural water courses. • Construction of new bridges and culverts in roads affected by floods.
Administration/Organization • Preparation of Contingency Plans. • Training of the staff responsible of rescue and other actions related to disaster management. • Improvement of living conditions in low risk areas to flood events in order to reduce migrations towards high and moderate risk areas.
Planning • Identification of flood prone areas at region and settlement level. • Preparation of feasibility studies to improve living conditions in settlements selected to relocate population residing in flood prone areas. • Preparation of urban plans with emphasis in environmental aspects. • Preparation of urban regulations.
Maintenance • Recovery, improvement and maintenance of natural and man-made water courses.
Control • Implementation of regional and urban regulations to avoid new developments in flood prone areas (low-lying areas, floodplains, etc.)
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 179 Northern Regions. Flood Risk Management Plan 2011
5.2 – GENERAL PROPOSALS FOR URBAN AREAS Planning authorities will introduce flood risk assessment as an integral and leading element of their development planning functions. The new flood risk assessment system will introduce processes for identifying flood risk and determining what flood risk assessment is required and carrying out such assessments similar to the overall system for screening and scoping. Town development plans will establish the flood risk assessment requirements for their functional areas including other planning authorities such as Town Councils and any local area plans which may be supplemented by more detailed site-specific flood risk assessment. Planning authorities will ensure that development is not permitted in areas of flood risk, particularly floodplains, except where there are no suitable alternative sites available in areas at lower risk that are consistent with the objectives of proper planning and sustainable development. Where such development has to take place, in the case of urban regeneration for example, the type of development has to be carefully considered and the risks should be mitigated and managed through location, layout and design of the development to reduce flood risk to an acceptable level. Earlier town planning has not been sufficient and buildings have been constructed on the low-lying areas without proper storm water management. Currently, even the building approvals do not indicate the required floor levels of the buildings. Because of exceptional water levels must be kept in mind so that new structures will not be built in the possible floodwater basins. Applications for planning permission: In the case of applications for planning permission and development consents to planning authorities, applicants and their agents are required to carefully examine their development proposals, including carefully researching whether there have been instances of flooding or there is the potential for flooding, on specific sites and declaring any known flood history, engage with planning authorities at an early stage, utilizing the arrangements for pre-planning application consultation with regard to any flood risk assessment issues that may arise and carry out a site-specific flood risk assessment, as appropriate, and comply with the terms and conditions of any grant of planning permission with regard to the minimization of flood risk. Health issues: Flooding can cause many potential health problems to residents of the town. While storm water is mixing up with sewerage water, it is likely that pools of water will be contaminated by such bacteria as fecal coliform, clostridium viable, som. coliphage and vibrio chlolerae. When contaminated water is used for human consumption, these bacteria
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 180 Northern Regions. Flood Risk Management Plan 2011 may cause severe diseases such as diarrhea and cholera. After the rains, mosquitoes begin to nest in stable pools of water. Permanent drainage routes: When dry season begins and most of the water has gone, opened drainage routes have to be strengthened and protected from erosion. Routes, which are considered permanent solutions, have to be also enlarged so that their capacity is sufficient for future development and exceptional situations. Town Planning and Building Inspection. Construction levels: Town planning should be strict when approving building plans. Thumb rule for buildings’ floor level is +300 mm from the road level and +100 mm for the plot in general. Storm water should be always diverted to roadside channels or own storm water sewerage, not to the erven. In any case, it is always best to over calculate a bit than to follow the easiest path. Storm water drainage: In the future, when new plots will be constructed, they have to be equipped with storm water channeling or sewerage, which divert the water to nearby natural drainage route. Public health and emergency situations. Contingency Plan: In general, it is wise to have a contingency plan for situations where public health is threatened. The Town Council should be prepared for sudden drought, flooding and electricity breaks as well as situations when supporting routes are cut off. In this kind of emergencies, basic needs of the population and animals (cattle) have to be secured one way or another. Is recommended to imply at least a brief emergency plan where is indicated what needs to be done in a certain situation, who is responsible and where the necessary equipment and support can be obtained. Flooding and diseases: As mentioned before, floodwater is not ever pure and it contains always a potential health risk as well as suitable platform for breeding malaria mosquitoes. Furthermore, floodwater can move animal carcasses and other dangerous objects from one place to another. In any case, disease infections are probable through human contacts. Drought: Animals are dying because of water shortage and their carcasses pose a serious health risk, while carrying dangerous diseases, in populated areas. Carcasses should be buried under the ground in depth of one meter (at least), in order to prevent dangerous bacteria to mix up with future floodwater. For example, anthrax bacteria can survive in the ground for many years. In case that potable water supply is not adequate or system is damaged, drinking water must be obtained somewhere and delivered to the resident.
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Electricity breaks: When electricity is cut off, everything shuts down. Following problems may occur: sewerage and water pumps will not work, stores’ coolers will shut down (food will be spoiled), phones do not connect et cetera. Although, the Town Council is not responsible of electricity (while Northern Electricity, Nored, is) reserve power sources and petrol should be stored in key locations to provide electricity for short-term periods. Chemical accidents and firefighting: When chemicals or petrol is delivered through the main road, accidents may occur time to time. How local residents are protected when toxic gas is released or when petrol tanker is burning? What is the first responding unit, how well firefighters are equipped and how people are warned in case of emergency? It is recommendable to have a common alert mechanism such as sirens, when people are instructed to be inside their houses. Then by listening radio, people can get further instructions. Supplement method is to have patrols with protective clothing to circle around in the areas where radios are not available. Announcements: Efficient announcing is the key method for preventing potential losses of life and health crises. However, it is difficult to change traditions and cultural behavior although advertising is already widespread. It is only a matter of time; new generations will get adapted to new recommendations easily, the previous ones only slowly. Anyway, instructions should be given by using any means necessary (role-plays, radio, newspapers, Sunday’s services, leaflets, from loudspeakers etc.) and in advance before the future incidents.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 182
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CAPRIVI REGION FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 183 Northern Regions. Flood Risk Management Plan 2011
6.0 – SPECIFIC PROPOSALS PER REGIONS AND URBAN AREAS
6.1– CAPRIVI REGION
6.1.1 – Regional Proposals Considering the specific characteristics of the Caprivi Region, a set of general proposals for the whole region is enounced here, although more specific and detailed studies should be carried out in order to be implemented: ! Reforestation of main rivers banks and flood plains and other secondary streams in order to minimize fluvial erosion and badlands. ! Improvement of the water transport in Zambezi River (Katima Mulilo – Schuckmansburg – Impalila). ! Promote the population concentration in upgraded human settlements located in moderate and low risk zones (Bukalo, Kabbe, Lusese), taking into account the improvement of general services (public health, education, electricity, water supply). ! Preparation of a feasibility study about the possible upgrade of the existing conditions in Schuckmansburg settlement, in order to allow the relocation of affected people living in neighboring areas, in a semi-permanent status. ! Development of short terms crops in order to avoid major damages due to floods. ! Construction of protection works (reinforced concrete, stone walls) in areas with slopes of more than 30 %.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 184
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KATIMA MULILO TOWN FLOOD RISK MANAGEMENT PLAN
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 185 Northern Regions. Flood Risk Management Plan 2011
6.1.2 – Katima Mulilo Town Proposals The Development Proposals for the town will consider the identification of three major sectors, as well as the flood prone areas: Sector 1.- North area along the Zambezi River. Sector 2.- Eastern area. Sector 3.- Western area. Land Use proposals: Sector 1: North area along the Zambezi River: There is a need to prepare a Comprehensive Development Plan for the area, taking into consideration the existing land uses, such as: a) Hippo Lodge. b) Namwi Island. c) Brick Factory. d) Zambezi Primary School. e) Caprivi River Lodge. f) Houses. g) Holy Family Catholic Mission. h) Directorate of Parks & Wildlife (Ministry of Environment and Tourism). i) Protea Hotel Zambezi River Lodge. j) Boma area: High standard residential, Government offices, Primary School, Sports field. k) Zambezi Waterfront Tourism Park. l) Vacant Land. m) Border Post Proposed Land Uses for the North Area (Sector 1): ! Tourism related facilities. ! High standard residential ! Golf course (18 holes) ! Recreational areas for general population. ! There is an existing proposal to develop the North Western part of the area. Sector 2: Eastern Area: It includes the most compact town area. Most of the low-lying areas are located in this part. Dairy – Cowboy area is under project. Proposal of high standard residential along the road, with a gradual downgrade of the residential area with the inclusion of social services (schools, clinics, churches, etc.)
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This project will allow the relocation of population living in flood prone areas, such as: - Macaravan East. - Macaravan West (industrial plots). - Old Musika Area. - Katima Base (government land). Hage Geingob street: Rezoning of the residential uses along the road, especially in front of the Pick and Pay complex. Proposal of new development in two-story buildings (business and residential). New Town Council offices will be located in the corner of the Hage Geingob street and Main Road. Sector 3: Western Area: Most of the area is government owned land. The Katima Mulilo Town Council have requested the transfer the ownership to include the land in the future development. Possible development of agriculture activities, linked to factories located in the industrial area. The town requires the development of these activities due to its location in an isolated part of the country, with long distances to suppliers. The proposal will generate jobs for the local population. High Education Area: The existing education facilities, the Zambezi Vocational Training Center and the TE, require increasing the size of the area for future expansion. The existing Refuse Dump will be relocated to the West, outside town boundaries. Town extension proposal: Possible town extension to the East until the Botswana border, although the prevalence of flood prone areas with possible development in scattered high lands (islands). High income residential along the Botswana road. On the north side, consider the requirements for the Comprehensive Development Plan, which will consider only high standard residential development. Flood Prone Areas: For the flood prone areas farther regulations will be established, which shall apply to all lands within the existing urban area in the floodways or flood prone areas within the zoning jurisdiction of the town of Katima Mulilo that are subject to a one percent or greater chance of flooding in any given year.
The degree of flood protection required by these regulations is considered reasonable for regulatory purposes and is based on engineering and scientific methods of study. Larger floods may occur on rare occasions or the flood height may be increased by man-made or natural causes, such as ice jams and bridge openings restricted by debris.
Compliance with these regulations does not imply that lands outside a floodplain or flood prone areas or uses within such areas will be free from flooding or flood damage.
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6.1.2.2- Katima Mulilo Contingency Plan Katima Mulilo is characterized by the many flood areas within the eastern townlands area. Heavy rains in this town regularly flood mostly the informal settlements. The drainage is in the general south-eastern direction. The flatness of terrain and the low water table pose challenges to physical development in Katima. In large portions, especially in the south- eastern part, the water table is 1-3 meters deep. There is currently no drainage system in a town. The initial heavy rains and flooding during the years 2008 and 2009 flood events occurred in Caprivi Region. The northern and northeast areas were the most affected parts of the country. The main causes of the high damages produced by floods are related to the existing road network, that look like as a dikes, the presence of buildings in the middle of natural water ways and the location of large number of population in flood prone areas. The town of Katima Mulilo is the most concentrated human area and is the most affected by flood events in the Caprivi region. In spite of many negative perceptions of Katima Mulilo Town (including the high water table, old infrastructure and large number of inhabitants in informal areas), the present water and sewerage situation in Katima Mulilo is – technically - not bad, as water services are widespread and a sewerage network exists that discharges in effective oxidation ponds. Moreover, several development projects are in progress. Disaster profile. Katima Mulilo town is located between 950 – 1100 m. of altitude. Katima Mulilo’s physical environment is characterized by its relatively flat topography, some rivers and vast area of floodplains which form its unique for flora and fauna. There are some low-laying areas within town boundaries that are affected by heavy rainwater, aggravated by the lack of a proper water drainage system, provoking that the rainwater stands still; Flood prone areas in New Cowboy, 2009 affecting houses and other properties. Apart from natural depressions, it was also observed that the existing underground water table is very shallow. In some areas of the town the water table was located approximately at one meter under the soil surface. Residents of some informal settlement like New Cowboy, Butterfly and Choto, reported that during the heavy rainy season, water seepage would sometimes houses constructed from clay and mud to collapse. Ground water pollution is one of the biggest threats to the natural environment and human health. Uncontrolled solid waste disposal in a quarry used as dump site to the west of the town, less than 1 km from the river is of special concern. In the formal areas the existing sewerage system is serving to a relatively low density of housing. Pipe sections are long and consequently deep, implying the need for extensive pumping. In addition, the Town Council is assuming total responsibility for the sewerage service, even taking care of systems on private properties cleaning where people discharge solid waste into the system.
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The comparison between low housing densities (which imply a high rate of operation costs per user) and a full operation burden creates a big challenge for the operation of the system. While the sewerage system draws most of the local stakeholders’ attention, the situation in the informal areas is critical. There is no sewerage service in Katima Mulilo’s informal settlements. And there are a very limited number of individual sanitation facilities (latrines or septic tanks). Residents typically dig a hole in the ground and install privacy screens. Or use the bush as a facility. There is zero sanitation coverage in the informal areas that contributes to the already serious health and economic situation due to low economic growth and the high prevalence of HIV/AIDS. While these informal areas are under the process of formalization, the Town Council is lacking the appropriate tools to address the sanitation issues in these low income areas. Settled sewer is economically interesting if a majority of household is already equipped with septic tanks, which is not the case in Katima Mulilo. However, it might be interesting to promote the use of grit/grease traps at household level, so to progressively relief the operator’s burden in operating and maintaining a deep system. Scenario for planning purpose ! Hazard and resulting emergency Katima Mulilo town is affected during the rainy season by floods as consequences of heavy rainwater that inundate low lying areas within town boundaries and the overflow of the Zambezi River that surrounding the north part of the town, due to the high volume of water coming from the Zambezi basin. The emergency stated is only proclaimed by the central government. ! Likely triggers a) Early warning indicators and triggers: They are not an early warning system. The initial warnings come from the news by TV about heavy rains at neighbor countries and some information from INTERNET about climate and meteorological conditions in the south part of African Region. Nevertheless, sometimes appears news at national newspaper, like Namibian of January 18 / 2011: b) Responsible for monitoring the early warning indicators and triggers: There is no appointed person among the Town Council staff responsible for these tasks. The Civil Defense Committee exists but is not active on this town. They also have a specifical system in each informal settlement, in which some local peoples carry on the emergencies solutions. There are nine counselors that are the responsibles of the advices in case of emergency situation. Also have nine community halls that can be used as relocations sites. In some locations as Boma, all the people try to reacomodated its belongings into the proper houses in safer places like attics. In Choto nine families are usually relocated at these Community Halls. In Mahohoma, only five households need to be relocated, and in New Cowboy, all the people are usually moved from this area to some different safer places in a town.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 189
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! Risk analysis a) How likely is this scenario to occur? Despite of the fact that drought is the most common natural hazard to the majority of the country, during every rainy season (November – April) the area where Katima Mulilo town is located, becomes very vulnerable to flood events in a process that has seen a recurrence during the last three years. b) What will be the consequences should the scenario occur? The areas near the Zambezi River and it’s affluents as well as the existing low lying areas within town boundaries, are flooded affecting in a different way public and private properties. The lack of a proper storm water drainage system prevent the prompt evacuation of the water, causing a progressive increase in water levels as long as the main sources – heavy rains, overflow of the Zambezi – continue. One of the most vulnerable areas is the north part of the town along the border of this river, caused by the overflow of the Zambezi River. Another problem is the presence of the water canal in the middle of the town and the absence of appropriate hydraulic works (culverts, bridges and drifts). As a result of that fact, is possible to obtain the following table: Katima Mulilo. Table of existing vulnerability in the town:
Total Total of Total Kind of Hazard Vulnerability Vulnerability Vulnerability surface of housing population hazards level surface population household settlement High / Ha. # Hab. XXX Middle Ha. % Hab. % # % Storm High 858,0 30,0 7 025,0 25,0 1 088,3 22,0 2 860 4 947 28 100 water 1 086,8 38,0 3 006,7 10,7 4 848,1 9,8 flooding Middle High 1 172,6 41,0 9 835,0 35,0 1 533,6 31,0 2 860 4 947 28 100 Drought Middle ------
The main consequences should the scenario occur are: - Most of the businesses and commercial buildings located along the border of the river are flooded. - Contamination of the superficial and underground water due the overflow of the river, overflow of some wells and septic tanks located in some parts of the town and overflow of the tree oxidation ponds. - Some roads are interrupting, preventing the access to some areas, especially to the informal settlements Butterfly, Choto, Mafuta and New Cow Boy. - Lack of accessibility to some social services (schools, clinics, food and other services). - Relocation of affected population to the safer places into the town.
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! Population at risk Most of the population residing in Katima Mulilo town is at risk during a flood event, especially those living near the flood prone areas (Zambezi River, informal settlements, and central water canal). There is not exact idea of the total amount of people at risk, but could be more than 10 000 Hab. (almost the third part of the town). If you must evacuate in the event of a flood: ! Always follow the instructions of local emergency officials. ! Take your personal emergency grab-and-go kit with you. This kit should have basic essential items such as prescription medications, eye glasses, important papers, flashlight, battery powered radio, clothing, identification and some cash. ! Ensure each family member has waterproof clothing and footwear. ! Shut and lock doors and windows, including barn doors and gates. Shut off water supply, natural gas and power to all buildings, barns, etc. as identified on farm map. ! If you are evacuating your premises, shut off your gas valve at the meter. ! Rendezvous with family and workers at designated safe meeting place or at local Emergency Services Shelter. ! Anticipated duration of emergency conditions The duration of emergency conditions depends on the weather characteristics (meteorological situation – duration and intensity of rains, volume of flood water, etc.) and on the capacity of resilience of this region. ! Budget and other resources to face up to the disaster The total amount is of $250 000 N.D. from the regional level and some aids form owners of the establishments at the locality. They have also 13 big tents for a temporally relocation of the most affected people. It don’t exist any special government warehouse with food supply for the affected people, but in emergency cases is used some reserves from “M’pacha Military Base”. Main Objectives: ! Saving lives ! Preserving assets ! Preventing Mass Migration ! Ensuring access to public services for all the people ! Establishing conditions for restoring of self - reliance ! Minimize damage resulting from emergency situation
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 191
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Program Implementation: ! Immediate Response and Evacuations Routes When the disasters appear in this town, many means of transportation are designated for help the affected people. Some means from certain local business, private tracks and another soften transports are very useful for many critical situations. The district hospital is located at high and safer land, for special attention to the town’s people affected during the disaster and emergency situation. Tarred roads are used as principal way of transportation because are safer ways. Nevertheless, most of the roads are not tarred (gravel) so they are very affected by floods with problem of accessibility principally in informal settlements. After flooding is developed a campaign in order to avoid some very often diseases like cholera, malaria, dengue, etc. that could became in a very serious epidemics. Coordination of Emergency Response: The mechanism in the Caprivi and the Kavango Regions that experience flood disaster almost on an annual basis were directed and coordinated by the offices of the Regional Governors. Displaced people in the 2 regions were relocated to higher ground where emergency humanitarian was provided by Government, UN agencies and the Namibian Red Cross. Coordination at national level was not however clearly defined. The Directorate Emergency Management called two meetings for the national focal persons at which sector ministries including the Namibian Red Cross Society were requested to compile three months sectoral response plans. ! Long term plans In Katima they haven’t any rescue team, or Red Cross organization and neither firefighter. It also doesn’t have any educative or informational program to prepare and train a lot of people to confront these natural hazards, like flooding. ! Preparedness and Maintenance Actions A Plan will be updated and revised systematically and it is necessary to prepare some simulation exercises to test the plan and also a proper preparation and capacitation in order to avoid big quantities damages. At regional level however, the Namibian Disaster Management System (NDMS) appointed two senior people to oversee the coordination of the disaster response. The roles of the two senior officers were among others to: ! Provide a link between disaster response operational levels with the NDMS through weekly report to the Secretary to Cabinet (Chairperson of the National Emergency Management Committee) ! Received donations and facilitate timely distribution to the flood affected ! Continuously monitor the flood situation and facilitating the provision of appropriate response
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 192
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! Coordinating transport and logistic ! Conducting weekly meetings on the flood disaster response with stakeholders ! Providing media briefs on the flood situation ! Developing medium and long term recommendation for effective flood management and rehabilitation And also, ! The Regional Councils should consider disaster management as an integral part of their activities and not an add on activity and responsibilities given to staff that have other key roles to play in the Regional Councils. ! Regional Emergency Management Units need to be continuously proactive and sensitive to the disaster risk management and should strengthen coordination among all the stakeholders before, during and after disasters. ! To facilitate coordination of disaster risk management activities (preparedness and contingency planning, public awareness, secretariat for the regional council disaster technical committee, beneficiary registration and tracking and monitoring supplies of food and not - food distribution), Regional Council should be encouraged to fill the positions of Regional Disasters Management Coordinators. Some solutions to the flood problem: Floods are a consequence of natural hydro-meteorological phenomenon, combined with their interaction with the catchment characteristics. Through interventions in changing the characteristics of the catchment the run-off processes can be altered, thereby making it possible to reduce the magnitude of the flood hazard thus generated. Urban drainage systems, made up of channels, culverts, sewers etc., are meant to prevent local floods by conveying storm water away from vulnerable sites. Mostly this is done with the aim of draining storm water as fast as possible out of town. This practice may be benign in coastal cities or in agglomerations with no exposed living spaces downstream, but if cities or urban districts upstream of other riverside settlements drain storm water too quickly, this may cause urban floods downstream. Thus the sustainable urban drainage systems aim for adequate, but not too excessive, drainage in order to mitigate local floods, without creating new hazards downstream. Commonly it presents two major concepts of urban storm drainage: direct runoff versus source control. The latter concept suggests a number of so-called “source control measures” which are meant to either retain or reduce storm water runoff in order to prevent the exceedance of the drainage system and to mitigate the generation of flood hazards downstream. The resulting hydrographs illustrate how the reduction and retention of storm water runoff in a source control drainage systems can cut discharge peaks. The reduction of surface runoff in absolute terms can be achieved by a variety of measures that increase infiltration, evaporation and/or transpiration from the catchment areas that contribute to local flooding. The easiest way to do so is to preserve unsealed and greened spaces in the city. Such spaces are of multifunctional purpose, they reduce
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 193
Northern Regions. Flood Risk Management Plan 2011 surface runoff by increasing infiltration and evapotranspiration; retain water through interception; filter the percolating water; recharge groundwater resources; reduce air pollution and improve the urban microclimate; and can be used for recreational purposes in the form of parks and gardens. Since the availability of space is highly limited in cities, less extensive measures that enable effective in-town infiltration can also be used. Among them are: infiltration trenches; soak- aways; and measures that increase the permeability of larger surfaces. Essentially, infiltration trenches and soakaways consist of a trench or a pit filled with a top layer of permeable material like crushed stones or gravel and a bottom layer of sand. Since the potential for in-town infiltration and evapotranspiration is limited, especially in cities where convective precipitation and non-absorptive soils prevail, measures of storm water retention are vital for the mitigation of urban floods as well as for the prevention of downstream floods. Storm water retention can be achieved or facilitated by constructing basins or ponds that temporarily store surface runoff and release it subsequently at a controlled rate. There is a variety of retention basins and ponds - open or covered, wet or dry, online or offline – that may serve various purposes. The advantage of multipurpose dry ponds is the maximization of land use. They can also contribute to infiltration and to the removal of pollutants. There are many creative possibilities to use the same space for everyday activities as well as for occasional flooding. Furthermore, wet ponds in the form of artificial lakes can be of aesthetic value. Temporary storm water retention can be made in sport courts, parking sites, playgrounds etc. In all cases sedimentation has to be considered a likely problem in basins and ponds. These retention basins require flow equalization facilities to prevent flooding of and damage to such facilities. A complementary multipurpose retention strategy is storm water storage as a source of water supply, so-called “rainwater harvesting”. This is particularly useful in semi-arid areas that experience water stress. Considering economic and environmental advantages and its potential for mitigation of urban floods, rainwater harvesting is not only applicable in towns where fresh water resources are scarce but constitutes a reasonable measure in almost all human settlements. Although unfiltered storm water is normally not of drinking water quality, it is amenable for non-potable purposes such as washing, irrigation, toilet flushing etc. Storm water is usually collected on roofs and stored in tanks or in underground cisterns. Implementation: The purpose of this plan is to inform and guide all the local stakeholders in the undertaking of its planning responsibilities, and in integrating and coordinating the activities of different agencies that influence the use and development of land that may be affected by natural hazards. The plan will also guide local governments, other agencies and state government of those aspects of state planning policy concerning natural hazard mitigation that should be taken into account in planning decision-making. There are many agencies that have the power to permit development that may be subject to natural hazards. While recognizing these responsibilities, this plan provides a checklist to enable the delivery of a consistent approach to natural hazard mitigation.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 194
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 195
Northern Regions. Flood Risk Management Plan 2011
KAVANGO REGION FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 196 Northern Regions. Flood Risk Management Plan 2011
6.2 – KAVANGO REGION
6.2.1 – Regional Proposals Through this study it was possible to assess the impact of the flooding in some of the social service and technical infrastructure in the context of Kavango Region, setting proposals and recommendation to the government that facilitate the decision making process. Even if Kavango Region was not affected as the same magnitude of other regions there are some village, schools, roads and others buildings that were damage and need punctual solutions to solve the problem. It is consider the main cause of the problem the location of investment near to the riverside and in low lying areas. The situation of Kavango Region has to be seen as part of the territorial context that will be solved with an integral study of the northern hydrographic Namibia-Angola basin. The general recommendations for the whole region are:
! Reforestation of main rivers banks and flood plains and other secondary streams in order to minimize fluvial erosion and badlands.
! Preparation of a planning study with a new settlement system proposal.
! Preparation of a new land use proposal, incorporating regulations in order to guide the relocation of people living in flood prone areas to higher and safer zones.
! Consider the zone between the Kavango river and the Divundu - Rundu and Rundu – Nkurenkuru roads as green areas for the development of agriculture (short period crops), woodland, proposing a gradual relocation process to the existing settlements to higher lands.
! Keep grazing lands for cattle, considering its relocation to nearby higher lands during the occurrence of floods events.
! Increase capacity of culverts to accommodate flood and storm water in roads and gravel roads.
! Upgrading of human settlements in the low risk zones in order to reduce migration movements to the high and moderate risk zones.
! Preparation of underground storm water drainage system for Rundu town.
! Construction of protection works to avoid erosion to roads in Kavango river nearby areas.
! Complete the formalization study for Kehemu informal settlement, proposing urban and technical solutions to existing flood problems.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 197
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RUNDU TOWN FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 198 Northern Regions. Flood Risk Management Plan 2011
6.2.2- Rundu Town Proposals The town of Rundu is located in the central area of the Kavango Region and it is regarded as the capital town of the Region. The town has experienced rapid growth in recent years, although this development is affected by the serious damages that some technical infrastructure -especially roads- face every year during the rainy season, when most of the roads are washed away, because of inadequate and or absence of storm water provisions. At the same time, there are some catchment areas within town boundaries that need infrastructural solutions to evacuate the rain waters, especially in the following areas: Kehemu, Rundu beach, Kavango River Lodge, Corner in front of Omashare Lodge as well as in the area located behind the Regional Council offices. Although almost the whole town is already connected to the new sewerage system and the new oxidation ponds located on the south part, the old system is still receiving some of the dark waters, because functional problems of the pump station responsible to redirect the sewerage to the new system, causing the pollution of the Kavango River. It is necessary to implement a policy of relocation for all the informal population migrating and settling outside of the planned areas. The Development Proposals for the town will consider the identification of four major sectors, as well as the flood prone areas: Sector 1. - Existing urban area along the Kavango River. Sector 2. - Southeastern area. Sector 3. - Northeastern area. Sector 4. - Southwestern area (airport and military base) Land Use Proposals: Sector 1: Completion of the vacant land located within the sector, including infrastructural solution, specially the storm water drainage system. Proposal for Storm Water Drainage System Rundu is situated in higher grounds; as a result, the lower part of the town is always affected by the storm water drainage. Impermeable surfaces such as sink roof and surface roads create high storm water runoff flow into the floodplain of the Kavango River. The flood waters affect the town as a result, some of the local lodges have to be temporarily closed and the facilities built in the floodplain area are destroyed. The town does not have a proper Storm Water Drainage Master Plan. The current concrete storm water channels are not adequate to drain storm water runoff, and there are not underground pipes. Few open concrete channels can be observed in the town central area. Roads in Rundu Extensions 2,3,6,7 and 8 are completely destroyed during rainy season and need to be rehabilitated in a yearly basis. The newly constructed surfaced roads: Independence road (7.5 km), Eugene Kakukuru (3.0 km), Markus Siwarongo (2.5 km) don’t have underground storm water channels, as a result storm water runoff into private properties and cause massive damage to the municipal infrastructure. At the same time, roads in certain areas are higher than the level of the building foundations.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 199
Northern Regions. Flood Risk Management Plan 2011
The most affected areas are:
Area Cause of Damage Existing underground storm water drainage is blocked; as a result the 350 mm sewerage pipeline is washed Rundu extension 2 out and the new surveyed land in extension 9 is complete damaged Rundu extension 3 Road to Rundu Beach, Maria Muengere Road Road to Calai/Namibia Border Post Road, Maria Rundu extension 6 Muengere Road Rundu extension 1 and Rundu Town Side cracking, inadequate drainage system Rundu extensions 7 and 8 No drainage system, roads not developed No storm water drainage infrastructure and roads are Rundu extension 4 and Ndama Township half developed Other areas in town No storm water drainage
A Storm Water Master Plan for Rundu should be developed to ensure that all future planning of the town is done accordingly.
Design Considerations: Underground pipes are considered as the best design option, considering the following advantages: ! Allow for more effective drainage. ! Erosion is avoided. ! It will provide a sustainable link to the underground storm water drainage systems that already exist. ! A storm water drainage pump station to be constructed at the lower area like Trade Fair centre, Industrial area and Ndama extension 1. Scope of work ! Construction of 30 kilometers of underground storm water channels. ! Construction of three (3) storm water drainage pump stations at Trade Fair grounds, Industrial area and Ndama extension 1. ! Rehabilitation of the existing underground storm water channels. ! Construction of paved roads. ! Earth works and bulk filling on the lower area. ! Construction of culvert/bridge at Kehemu.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 200
Northern Regions. Flood Risk Management Plan 2011
Financial implications: Consulting fees and design: N$ 1 157 800.00 Construction of three (3) storm water pump stations: N$ 4 000 000.00 Construction of 30km underground drainage: N$ 8 000 000.00 Construction of paved road to link the bridge Maria Muengere and Independence road: N$ 1 500 000.00 Earth works and bulk filling: N$ 400 000.00 Rehabilitation of existing storm water drainage system: N$ 300 000.00 Other areas around town: N$12 000 000.00 10% Contingencies N$ 1 540 000.00 TOTAL N$ 17 697 800.00 Sectors 2, 3: The southern and northeastern areas are used for small scale farming in the temporary timeframe. Kaisosi: agricultural development. Ndama: presence of power line. Proposal of a green corridor for the power line servitude of 50m wide. Sector 4. - Southwestern area. Presence of two major facilities: 1. Military Base (south of the road) 2. Airport (north of the road) Land around military base, from the southwestern murambas, is restricted because of the presence of the airport and military facilities. For the whole area, the settlement of population is restricted. Flood Prone Areas: For the flood prone areas farther regulations will be established, which shall apply to all lands within the existing urban area in the floodways or flood prone areas within the zoning jurisdiction of the town of Rundu that are subject to a one percent or greater chance of flooding in any given year.
The degree of flood protection required by these regulations is considered reasonable for regulatory purposes and is based on engineering and scientific methods of study. Larger floods may occur on rare occasions or the flood height may be increased by man-made or natural causes, such as ice jams and bridge openings restricted by debris.
Compliance with these regulations does not imply that lands outside a floodplain or flood prone areas or uses within such areas will be free from flooding or flood damage.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 201
Northern Regions. Flood Risk Management Plan 2011
6.2.2.2- Rundu Town. Contingency Plan Rundu town constitutes the capital of the Region. It is located between 1000 – 1500 m. of altitude. The town is affected mostly by heavy rains, which provoke some damages due to the prominent slopes, aggravated by the lack of a proper underground storm water drainage system. The rainwater provokes serious “erosion problems” in many areas and roads located near to the river banks, principally at gravel roads. The town’s northern part is flooded by the overflow of the Kavango River, affecting mostly illegal settlements and accommodation services (lodges). The most affected area within town boundaries are the informal settlements of Kaisosi, located on the most eastern part of Rundu, and Sauyemwa, another settlement at the west side of the town. In the formal areas of the towns, the existing sewerage system is serving to a middle density of housing. Pipe sections are long and consequently deep, implying the need for some extensive pumping. In addition, the Town Council is assuming total responsibility for the sewerage service, even taking care of systems on private properties cleaning where people discharge solid waste into the system. The comparison between low housing densities (which imply a high rate of operation costs per user), and a full operation burden creates a big challenge for the operation of the system. While the sewerage system draws most of the local stakeholders’ attention, the situation in the informal areas is critical. There is no sewerage service in Rundu’s informal settlements. And there are a very limited number of individual sanitation facilities (latrines or septic tanks). Residents typically dig a hole in the ground and install privacy screens. Or use the bush as a facility. There is zero sanitation coverage in the informal areas that contributes to the already serious health and economic situation due to low economic growth and the high prevalence of HIV/AIDS. While these informal areas are under the process of formalization, the Town Council is lacking the appropriate tools to address the sanitation issues in these low income areas. Settled sewer is economically interesting if a majority of household is already equipped with septic tanks. However, it might be interesting to promote the use of grit/grease traps at household level, so to progressively relief the operator’s burden in operating and maintaining a deep system.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 202
Northern Regions. Flood Risk Management Plan 2011
Scenario for planning purpose ! Hazard and resulting emergency Rundu town is affected during the rainy season by floods as consequences of heavy rainwater that inundate low lying areas within town boundaries and the overflow of the Kavango River that surrounding the north part of the town, due to the high volume of water coming from the Kavango basin. The emergency stated is only proclaimed by the central government. ! Likely triggers c) Early warning indicators and triggers: They are not an early warning system. The initial warnings come from the news by TV about heavy rains at neighbor countries and some information from a Central Office of the Ministry of Agriculture and from INTERNET about climate and meteorological conditions in the south part of African Continent. Nevertheless, sometimes appears news at national newspaper, like Namibian of January 18 / 2011: d) Responsible for monitoring the early warning indicators and triggers: There is no appointed person among the Town Council staff responsible for these tasks. The Civil Defense Committee exists and it is active on this town. They also have a proper system in each informal settlement, in which some local peoples carry on the emergencies solutions. All the people are usually moved from these areas to some different safer places in a town. ! Risk analysis c) How likely is this scenario to occur? Despite of the fact that drought is the most common natural hazard to the majority of the country, during every rainy season (November – April) the area where Rundu town is located, becomes very vulnerable to flood events in a process that has seen a recurrence during the last three years. d) What will be the consequences should the scenario occur? The areas near the Kavango River and it’s effluents as well as the existing low lying areas within town boundaries, are flooded affecting in a different way public and private properties, specially some lodges at the border of the river. The lack of a proper storm water drainage system prevent the prompt evacuation of the water, causing a progressive increase in water levels as long as the main sources – heavy rains, overflow of the Kavango – continue. One of the most vulnerable areas is the north part of the town along the border of this river, caused by the overflow of the Kavango River. Another problem is the absence of appropriate hydraulic works (culverts, bridges and drifts), or some culverts that are obstructed.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 203
Northern Regions. Flood Risk Management Plan 2011
As a result of that fact, is possible to obtain the following table: Rundu Town. Table of existing vulnerability in the town: Total Total of Total Kind of Hazard Vulnerability Vulnerability Vulnerability surface of housing population hazards level surface population household settlement High / Ha. # Hab. XXX Middle Ha. % Hab. % # % 21 Storm High 3618,0 21,0 28,0 3 681,0 28,0 16 969,0 13 146 76 250 water 350,0 flooding Middle 312,5 1,0 678,5 4,0 509,0 3,0 20 High 5 260,4 31,0 27,0 3 549,6 27,0 16 969,0 13 146 76 250 Drought 587,5 Middle ------
The main consequences should the scenario occur are: - Most of the businesses and commercial buildings located along the border of the river are flooded, including the lodges. - Contamination of the superficial and underground water due the overflow of the river, overflow of some wells and septic tanks located in some parts of the town and overflow of the oxidation ponds. - Some roads are interrupting, preventing the access to some areas, especially to the informal settlements. - Lack of accessibility to some social services (schools, clinics, food and other basic services). - Relocation of affected population to the safer places into the town. ! Population at risk Most of the population residing in Rundu town is at risk during a flood event, especially those living near the flood prone areas (Kavango River, informal settlements, and low lying areas). There is not exact idea of the total amount of people at risk, but could be more than 30 000 Hab. (almost the 40% of the town). If you must evacuate in the event of a flood: ! Always follow the instructions of local emergency officials. ! Take your personal emergency grab-and-go kit with you. This kit should have basic essential items such as prescription medications, eye glasses, important papers, flashlight, battery powered radio, clothing, identification and some cash. ! Ensure each family member has waterproof clothing and footwear. ! Shut and lock doors and windows, including barn doors and gates. Shut off water supply, balloon gas and power to all buildings, barns, etc. as identified on the map. ! If you are evacuating your premises, shut off your gas valve at the meter. ! Rendezvous with family and workers at designated safe meeting place or at local Emergency Services Shelter.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 204
Northern Regions. Flood Risk Management Plan 2011
! Anticipated duration of emergency conditions The duration of emergency conditions depends on the weather characteristics and conditions (meteorological situation – duration and intensity of rains, volume of flood water, etc.) and on the capacity of resilience of this region. ! Budget and other resources to face up to the disaster It don’t exist any special government warehouse with food supply for the affected people, but in emergency cases is used some strategic reserves from the Central Government. Main Objectives: ! Saving lives ! Preserving assets ! Preventing Mass Migration ! Ensuring access to public services for all the people ! Establishing conditions for restoring of self - reliance ! Minimize damage resulting from emergency situation Program Implementation: ! Immediate Response and Evacuations Routes When the disasters appear in this town, many means of transportation are designated for help the affected people. Some means from certain local business, private tracks and another soften transports are very useful for many critical situations. The district hospital is located at a safer land, for special attention to the town’s people affected during the disaster and emergency situation. Tarred roads are used as principal way of transportation because are safer ways. Nevertheless, most of the roads are not tarred (gravel) so they are very affected by floods with problem of accessibility principally in informal settlements. Also all of roads are affected by strong erosion that is able to destroy them. After flooding is developed a campaign in order to avoid some very often diseases like cholera, malaria, dengue, etc. that could became in a very serious epidemics. ! Long term plans In Rundu they haven’t any rescue team, or Red Cross organization and neither firefighter. It also doesn’t have any educative or informational program to prepare and train a lot of people to confront these natural hazards, like flooding.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 205
Northern Regions. Flood Risk Management Plan 2011
! Preparedness and Maintenance Actions A Plan will be updated and revised systematically and it is necessary to prepare some simulation exercises to test the plan and also a proper preparation and capacitation in order to avoid big quantities damages. At regional level however, the Namibian Disaster Management System (NDMS) appointed two senior people to oversee the coordination of the disaster response. The roles of the two senior officers were among others to: ! Provide a link between disaster response operational levels with the NDMS through weekly report to the Secretary to Cabinet (Chairperson of the National Emergency Management Committee) ! Received donations and facilitate timely distribution to the flood affected ! Continuously monitor the flood situation and facilitating the provision of appropriate response ! Coordinating transport and logistic ! Conducting weekly meetings on the flood disaster response with stakeholders ! Providing media briefs on the flood situation ! Developing medium and long term recommendation for effective flood management and rehabilitation And also, ! The Regional Councils should consider disaster management as an integral part of their activities and not an add on activity and responsibilities given to staff that have other key roles to play in the Regional Councils. ! Regional Emergency Management Units need to be continuously proactive and sensitive to the disaster risk management and should strengthen coordination among all the stakeholders before, during and after disasters. ! To facilitate coordination of disaster risk management activities (preparedness and contingency planning, public awareness, secretariat for the regional council disaster technical committee, beneficiary registration and tracking and monitoring supplies of food and not - food distribution), Regional Council should be encouraged to fill the positions of Regional Disasters Management Coordinators. Some solutions to the flood problem: Floods are a consequence of natural hydro-meteorological phenomenon, combined with their interaction with the catchment characteristics. Through interventions in changing the characteristics of the catchment the run-off processes can be altered, thereby making it possible to reduce the magnitude of the flood hazard thus generated.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 206
Northern Regions. Flood Risk Management Plan 2011
Urban drainage systems, made up of channels, culverts, sewers etc., are meant to prevent local floods by conveying storm water away from vulnerable sites. Mostly this is done with the aim of draining storm water as fast as possible out of town. This practice may be benign in coastal cities or in agglomerations with no exposed living spaces downstream, but if cities or urban districts upstream of other riverside settlements drain storm water too quickly, this may cause urban floods downstream. Thus the sustainable urban drainage systems aim for adequate, but not too excessive, drainage in order to mitigate local floods, without creating new hazards downstream. Commonly it presents two major concepts of urban storm drainage: direct runoff versus source control. The latter concept suggests a number of so-called “source control measures” which are meant to either retain or reduce storm water runoff in order to prevent the exceedance of the drainage system and to mitigate the generation of flood hazards downstream. The resulting hydrographs illustrate how the reduction and retention of storm water runoff in a source control drainage systems can cut discharge peaks. The reduction of surface runoff in absolute terms can be achieved by a variety of measures that increase infiltration, evaporation and/or transpiration from the catchment areas that contribute to local flooding. The easiest way to do so is to preserve unsealed and greened spaces in the city. Such spaces are of multifunctional purpose, they: Reduce surface runoff by increasing infiltration and evapotranspiration; Retain water through interception; Filter the percolating water; Recharge groundwater resources; Reduce air pollution and improve the urban microclimate; and Can be used for recreational purposes in the form of parks and gardens. Since the availability of space is highly limited in cities, less extensive measures that enable effective in-town infiltration can also be used. Among them are: Infiltration trenches; Soak-aways; and Measures that increase the permeability of larger surfaces. Essentially, infiltration trenches and soakaways consist of a trench or a pit filled with a top layer of permeable material like crushed stones or gravel and a bottom layer of sand. Since the potential for in-town infiltration and evapotranspiration is limited, especially in cities where convective precipitation and non-absorptive soils prevail, measures of storm water retention are vital for the mitigation of urban floods as well as for the prevention of downstream floods. Storm water retention can be achieved or facilitated by constructing basins or ponds that temporarily store surface runoff and release it subsequently at a controlled rate. There is a variety of retention basins and ponds - open or covered, wet or dry, online or offline – that may serve various purposes. The advantage of multipurpose dry ponds is the maximization of land use. They can also contribute to infiltration and to the removal of pollutants.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 207
Northern Regions. Flood Risk Management Plan 2011
There are many creative possibilities to use the same space for everyday activities as well as for occasional flooding. Furthermore, wet ponds in the form of artificial lakes can be of aesthetic value. Temporary storm water retention can be made in sport courts, parking sites, playgrounds etc. In all cases sedimentation has to be considered a likely problem in basins and ponds. These retention basins require flow equalization facilities to prevent flooding of and damage to such facilities. A complementary multipurpose retention strategy is storm water storage as a source of water supply, so-called “rainwater harvesting”. This is particularly useful in semi-arid areas that experience water stress. Considering economic and environmental advantages and its potential for mitigation of urban floods, rainwater harvesting is not only applicable in towns where fresh water resources are scarce but constitutes a reasonable measure in almost all human settlements. Although unfiltered storm water is normally not of drinking water quality, it is amenable for non-potable purposes such as washing, irrigation, toilet flushing etc. Storm water is usually collected on roofs and stored in tanks or in underground cisterns. Implementation: The purpose of this plan is to inform and guide all the local stakeholders in the undertaking of its planning responsibilities, and in integrating and coordinating the activities of different agencies that influence the use and development of land that may be affected by natural hazards. The plan will also guide local governments, other agencies and state government of those aspects of state planning policy concerning natural hazard mitigation that should be taken into account in planning decision-making. There are many agencies that have the power to permit development that may be subject to natural hazards. While recognizing these responsibilities, this plan provides a checklist to enable the delivery of a consistent approach to natural hazard mitigation.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 208
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 209
Northern Regions. Flood Risk Management Plan 2011
NKURENKURU TOWN FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Pagege 210 Northern Regions. Flood Risk Management Plan 2011
6.2.3- Nkurenkuru Town Proposals The town is strategically located alongside the Kavango River linking Kavango Region with Ohangwena and Oshikoto Regions and via Katwitwi border post to the most densely populated area of Kwando-Kubango Province in the Republic of Angola. The majority of the areas affected by the overflow of the Kavango River are vacant at the present time, but have been planned for different land uses without considering this problem. In the Kahenge Constituency near the Kavango River the municipality implemented an area for sand extraction as building material which it has serious problems of erosion, affecting structure of soils and natural vegetation in this area. The Development Proposals for the town will consider the identification of two major sectors, as well as the flood prone areas: Sector 1. - Existing urban area. Sector 2. – Vacant land located within town boundaries. Land Use Proposals: Sector 1: Completion of the vacant land located within the sector, including infrastructural solution, specially the storm water drainage system. Sector 2: A revision of the existing plans is necessary and a new town scheme is required considering the environmental aspects in order to avoid damages to possible future developments in the area. Flood Prone Areas: For the flood prone areas farther regulations will be established, which shall apply to all lands within the existing urban area in the floodways or flood prone areas within the zoning jurisdiction of the town of Nkurenkuru that are subject to a one percent or greater chance of flooding in any given year.
The degree of flood protection required by these regulations is considered reasonable for regulatory purposes and is based on engineering and scientific methods of study. Larger floods may occur on rare occasions or the flood height may be increased by man-made or natural causes, such as ice jams and bridge openings restricted by debris.
Compliance with these regulations does not imply that lands outside a floodplain or flood prone areas or uses within such areas will be free from flooding or flood damage.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 211
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6.2.3.2- Nkurenkuru Town. Contingency Plan The town’s northern and northeast parts are flooded by the overflow of the Kavango River. Scenario for planning purpose ! Hazard and resulting emergency Nkurenkuru town is affected during the rainy season by floods as consequences of heavy rainwater that inundate low lying areas within town boundaries and the overflow of the Kavango River that surrounding the north and northeast part of the town, due to the high volume of water coming from the Kavango basin. The emergency stated is only proclaimed by the central government. ! Likely triggers e) Early warning indicators and triggers: They are an early warning system with its own local office belong of Agriculture Ministry that has a proper Meteorological Station. The initial warnings come from the news by TV about heavy rains at neighbor countries and some information from a Central Office of the Ministry of Agriculture and from INTERNET about climate and meteorological conditions in the south part of African Continent. Nevertheless, sometimes appears news at national newspaper, like Namibian of January 18 / 2011: f) Responsible for monitoring the early warning indicators and triggers: There is no appointed person among the Town Council staff responsible for these tasks. The Civil Defense Committee exists and it is active on this town. They also have a proper system in each informal settlement, in which some local peoples carry on the emergencies solutions. All the people are usually moved from these areas to some different safer places in a town. ! Risk analysis e) How likely is this scenario to occur? Despite of the fact that drought is the most common natural hazard to the majority of the country, during every rainy season (November – April) the area where Nkurenkuru town is located, becomes very vulnerable to flood events in a process that has seen a recurrence during the last three years. f) What will be the consequences should the scenario occur? The areas near the Kavango River and its effluents as well as the existing low lying areas within town boundaries, are flooded affecting in a different way public and private properties, specially some lodges at the border of the river. The lack of a proper storm water drainage system prevent the prompt evacuation of the water, causing a progressive increase in water levels as long as the main sources – heavy rains, overflow of the Kavango – continue. One of the most vulnerable areas is the north part of the town along the border of this river, caused by the overflow of the Kavango River. Another problem is the absence of appropriate hydraulic works (culverts, bridges and drifts), or some culverts that are obstructed. As a result of that fact, is possible to obtain the following table:
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Nkurenkuru Town. Table of existing vulnerability in the town: Total Total of Total Kind of Hazard Vulnerability Vulnerability Vulnerability surface of housing population hazards level surface population household settlement High / Ha. # Hab. XXX Middle Ha. % Hab. % # % Storm High 14,2 10,0 711,5 9,3 93,0 9,0 141,7 1 033 7 650 water 12,1 8,5 627,3 8,2 83,7 8,1 flooding Middle High 33,9 23,5 1 560,6 20,4 202,4 19,6 141,7 1 033 7 650 Drought Middle ------
The main consequences should the scenario occur are: - Most of the businesses and commercial buildings located along the border of the river are flooded, including the lodges. - Contamination of the superficial and underground water due the overflow of the river, overflow of some wells and septic tanks located in some parts of the town and overflow of the oxidation ponds. - Some roads are interrupting, preventing the access to some areas, especially to the informal settlements. - Lack of accessibility to some social services (schools, clinics, food and other basic services). - Relocation of affected population to the safer places into the town.
Population at risk Most of the population residing in Nkurenkuru town is at risk during a flood event, especially those living near the flood prone areas (Kavango River and low lying areas). There is not exact idea of the total amount of people at risk, but could be more than 1 300 Hab. (almost the 17% of the town). If you must evacuate in the event of a flood: ! Always follow the instructions of local emergency officials. ! Take your personal emergency grab-and-go kit with you. This kit should have basic essential items such as prescription medications, eye glasses, important papers, flashlight, battery powered radio, clothing, identification and some cash. ! Ensure each family member has waterproof clothing and footwear.
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! Shut and lock doors and windows, including barn doors and gates. Shut off water supply, natural gas and power to all buildings, barns, etc. as identified on farm map. ! If you are evacuating your premises, shut off your gas valve at the meter. ! Rendezvous with family and workers at designated safe meeting place or at local Emergency Services Shelter. ! Anticipated duration of emergency conditions The duration of emergency conditions depends on the weather characteristics and conditions (meteorological situation – duration and intensity of rains, volume of flood water, etc.) and on the capacity of resilience of this region. ! Budget and other resources to face up to the disaster It don’t exist any special government warehouse with food supply for the affected people, but in emergency cases is used some strategic reserves from the Central Government. Main Objectives: ! Saving lives ! Preserving assets ! Preventing Mass Migration ! Ensuring access to public services for all the people ! Establishing conditions for restoring of self - reliance ! Minimize damage resulting from emergency situation Program Implementation: ! Immediate Response and Evacuations Routes When the disasters appear in this town, many means of transportation are designated for help the affected people. Some means from certain local business, private tracks and another soften transports are very useful for many critical situations. Tarred roads are used as principal way of transportation because are safer ways. Nevertheless, most of the roads are not tarred (gravel), so they are very affected by floods with problem of accessibility principally in low income settlement. Also some roads are affected by certain erosion that is able to damage them. After flooding is developed a campaign in order to avoid some very often diseases like cholera, malaria, dengue, etc. that could became in a very serious epidemy. ! Long term plans In Nkurenkuru they haven’t any rescue team, or Red Cross organization and neither firefighter. It also doesn’t have any educative or informational program to prepare and train a lot of people to confront these natural hazards, like flooding.
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! Preparedness and Maintenance Actions A Plan will be updated and revised systematically and it is necessary to prepare some simulation exercises to test the plan and also a proper preparation and capacitation in order to avoid big quantities damages. At regional level however, the Namibian Disaster Management System (NDMS) appointed two senior people to oversee the coordination of the disaster response. The roles of the two senior officers were among others to: ! Provide a link between disaster response operational levels with the NDMS through weekly report to the Secretary to Cabinet (Chairperson of the National Emergency Management Committee) ! Received donations and facilitate timely distribution to the flood affected ! Continuously monitor the flood situation and facilitating the provision of appropriate response ! Coordinating transport and logistic ! Conducting weekly meetings on the flood disaster response with stakeholders ! Providing media briefs on the flood situation ! Developing medium and long term recommendation for effective flood management and rehabilitation And also, ! The Regional Councils should consider disaster management as an integral part of their activities and not an add on activity and responsibilities given to staff that have other key roles to play in the Regional Councils. ! Regional Emergency Management Units need to be continuously proactive and sensitive to the disaster risk management and should strengthen coordination among all the stakeholders before, during and after disasters. ! To facilitate coordination of disaster risk management activities (preparedness and contingency planning, public awareness, secretariat for the regional council disaster technical committee, beneficiary registration and tracking and monitoring supplies of food and not - food distribution), Regional Council should be encouraged to fill the positions of Regional Disasters Management Coordinators. Some solutions to the flood problem: Floods are a consequence of natural hydro-meteorological phenomenon, combined with their interaction with the catchment characteristics. Through interventions in changing the characteristics of the catchment the run-off processes can be altered, thereby making it possible to reduce the magnitude of the flood hazard thus generated. Urban drainage systems, made up of channels, culverts, sewers etc., are meant to prevent local floods by conveying storm water away from vulnerable sites. Mostly this is done with the aim of draining storm water as fast as possible out of town. This practice may be benign in coastal cities or in agglomerations with no exposed living spaces downstream, but if cities
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Northern Regions. Flood Risk Management Plan 2011 or urban districts upstream of other riverside settlements drain storm water too quickly, this may cause urban floods downstream. Commonly it presents two major concepts of urban storm drainage: direct runoff versus source control. The latter concept suggests a number of so-called “source control measures” which are meant to either retain or reduce storm water runoff in order to prevent the exceedance of the drainage system and to mitigate the generation of flood hazards downstream. The resulting hydrographs illustrate how the reduction and retention of storm water runoff in a source control drainage systems can cut discharge peaks. The reduction of surface runoff in absolute terms can be achieved by a variety of measures that increase infiltration, evaporation and/or transpiration from the catchment areas that contribute to local flooding. The easiest way to do so is to preserve unsealed and greened spaces in the city. Such spaces are of multifunctional purpose, they: Reduce surface runoff by increasing infiltration and evapotranspiration; Retain water through interception; Filter the percolating water; Recharge groundwater resources; Reduce air pollution and improve the urban microclimate; and Can be used for recreational purposes in the form of parks and gardens. Since the availability of space is highly limited in cities, less extensive measures that enable effective in-town infiltration can also be used. Among them are: Infiltration trenches; Soak-aways; and Measures that increase the permeability of larger surfaces. Essentially, infiltration trenches and soakaways consist of a trench or a pit filled with a top layer of permeable material like crushed stones or gravel and a bottom layer of sand. Since the potential for in-town infiltration and evapotranspiration is limited, especially in cities where convective precipitation and non-absorptive soils prevail, measures of storm water retention are vital for the mitigation of urban floods as well as for the prevention of downstream floods. Storm water retention can be achieved or facilitated by constructing basins or ponds that temporarily store surface runoff and release it subsequently at a controlled rate. There is a variety of retention basins and ponds - open or covered, wet or dry, online or offline – that may serve various purposes. The advantage of multipurpose dry ponds is the maximization of land use. They can also contribute to infiltration and to the removal of pollutants. There are many creative possibilities to use the same space for everyday activities as well as for occasional flooding. Furthermore, wet ponds in the form of artificial lakes can be of aesthetic value. Temporary storm water retention can be made in sport courts, parking sites, playgrounds etc. In all cases sedimentation has to be considered a likely problem in basins
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Northern Regions. Flood Risk Management Plan 2011 and ponds. These retention basins require flow equalization facilities to prevent flooding of and damage to such facilities. A complementary multipurpose retention strategy is storm water storage as a source of water supply, so-called “rainwater harvesting”. Considering economic and environmental advantages and its potential for mitigation of urban floods, rainwater harvesting is not only applicable in towns where fresh water resources are scarce but constitutes a reasonable measure in almost all human settlements. Although unfiltered storm water is normally not of drinking water quality, it is amenable for non-potable purposes such as washing, irrigation, toilet flushing etc. Storm water is usually collected on roofs and stored in tanks or in underground cisterns. Implementation: The purpose of this plan is to inform and guide all the local stakeholders in the undertaking of its planning responsibilities, and in integrating and coordinating the activities of different agencies that influence the use and development of land that may be affected by natural hazards. The plan will also guide local governments, other agencies and state government of those aspects of state planning policy concerning natural hazard mitigation that should be taken into account in planning decision-making. There are many agencies that have the power to permit development that may be subject to natural hazards. While recognizing these responsibilities, this plan provides a checklist to enable the delivery of a consistent approach to natural hazard mitigation.
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CUVELAI BASIN FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 220 Northern Regions. Flood Risk Management Plan 2011
6.3 – CUVELAI BASIN
6.3.1 – General Proposals In the process to suggest the main recommended actions to deal with flood events in the area covered by the Cuvelai basin, it is very important to understand flooding in the Northern regions as a natural, annual and unavoidable event, considering different strategies according to the level of development in the affected areas. In order to face the problem, a set of general recommendations for the whole Cuvelai basin is proposed, altogether with a set of specific recommendations for each of the affected regions located within the Cuvelai basin. GENERAL RECOMMENDATIONS FOR THE WHOLE CUVELAI BASIN 1. General study on major hydraulic solutions. 2. Other planning studies. 3. Environmental Impact Assessment. 4. New developments in higher lands. 5. Relocation of vulnerable population. 6. Compensation of traditional houses. 7. Improvement of natural water ways. 8. Construction of small hydraulic works. 9. Development of small scale tolerable agricultural activities. 10. Rehabilitation of most affected roads and bridges. 11. Rehabilitation of most affected sewerage systems. 12. Improve community participation in disaster management.
1. General study on major hydraulic solutions The Cuvelai originates in Angola with its catchments falling between the Kunene and the Kavango " Okavango drainage system. The system is fed by a number of rivers, some of which have their headwaters as far north as the Encoco highlands in Angola, which receive on average over 800 mm of rain a year. As these seasonal waters move southward, the land becomes flatter and the rivers and channels meandering towards the Namibia border feed into each other at some places and part ways at others, forming a massive inland delta. A general study for the whole Cuvelai basin, including southern Angola, should be carried out in order to identify possible solutions that allow the mitigation of the floods impact on the northern regions of Namibia. 2. Other planning studies Flood risk management should be integrated into spatial planning policies at all levels to enhance certainty and clarity in the overall planning process. At Regional Level (Regional Councils) Regional planning guidelines should address flood risk by carrying out flood risk appraisal at a strategic level, focusing on the identification of the need for better co-ordination of local plans within their areas and between regional authority areas.
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Development plans should address flood risk by having the necessary flood risk assessments, including mapping of flood zones, in place at the critical decision making phases and the consideration of any subsequent amendments. Regional Authorities will be required to prepare a strategically focused flood risk appraisal at the regional level as an integral input to the preparation of regional planning guidelines, which act as a framework for ongoing co-ordination of the development plans of local authorities in their areas. At Local Level (Town Councils) Planning authorities will introduce flood risk assessment as an integral and leading element of their development planning functions. Planning authorities will ensure that development is not permitted in flood prone areas, except where there are no suitable alternative sites available in areas at lower risk that are consistent with the objectives of proper planning and sustainable development. Where such development has to take place, in the case of urban regeneration for example, the type of development has to be carefully considered and the risks should be mitigated and managed through location, layout and design of the development to reduce flood risk to an acceptable level. Planning authorities will ensure that only developments consistent with the overall policy and technical approaches of this Plan will be approved and permission will be refused where flood issues have not been, or cannot be, addressed successfully and where the presence of unacceptable residual flood risks to the development, its occupants or users and adjoining property remains. Introduction of especial legislation considering that planning permission refused for the reason that the proposed development is in an area which is at risk of flooding excludes compensation. According to these guidelines, a set of plans will be prepared, from a more general approach (the whole Cuvelai basin) to a more detailed approach (selected towns and settlements), including an intermediate study related to each affected region. The main purposes for each plan will be: 1. Cuvelai Basin Flood Risk Management Plan Preparation of a general planning study for the whole area covered by the Cuvelai basin, which will provide the strategic direction for flood risk management decisions in the whole affected area, from an examination of the risks from all sources of flooding (oshanas, heavy rains, etc.) of the risks to and potentially arising from developments on the area covered by the basin, including an examination of the effectiveness and environmental impacts of any control or mitigation measures to be incorporated in those developments. These plans will describe a range of traditional flood defenses (canals, bridges, culverts, dikes, damns) to non-structural responses such as flood warning and resilience measures at property level. The plan will combines the function of mitigating and monitoring flood risks and may include pre-flood, flood event or post-flood activities.
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2. Regional Flood Risk Management Plans Preparation of specific regional planning studies for the most affected regions located in the Cuvelai basin. The plan will be prepared for each selected region (Oshana, Omusati, Ohangwena and Oshikoto), with one general chapter integrating the whole geographical area. It will be carried out using tools and techniques of Territorial Planning, incorporating vulnerability of the geographical areas, specifically in human settlements. The existing situation will be analyzed; especially the population and human settlement distribution and the study outcome will be a set of general and specific recommendations to mitigate flood risks, which could include a new human settlement system proposal for each region. 3. Town Flood Risk Management Plans Preparation of specific management plans for the most affected urban areas located within the regional boundaries, with the incorporation of urban planning studies, with emphasis in environmental analysis on the subject of risks and vulnerabilities to flood events. The flood risk management plans should be prepared for 8 selected towns and settlements: Oshana Region: Oshakati, Ongwediva, Ondangwa Omusati Region: Outapi, Okahao, Oshikuku, Okalongo (settlement area) Ohangwena Region: Helao Nafidi Phase 1: Preparation, reformulation or completion of the urban plans, considering existing situation at the beginning of the study, taking into consideration the required lands for new developments, relocation of population living in vulnerable areas and formalization of the informal settlements located within town boundaries. Phase 2: Preparation of the Development Proposal and Contingency Plan, which include preparedness, maintenance and flood mitigation actions in the identified areas at risk, land use projections and functional structure for undeveloped land within town boundaries, including general planning proposals and regulations for future development, infrastructure solutions (roads, water supply, sewerage, drainage) considering to avoid the risk where possible, substitute less vulnerable uses where avoidance is not possible, and mitigate and manage the risk where avoidance and substitution are not possible. 3. Environmental Impact Assessment The implementation of the solutions proposed in the studies will require an exhaustive analysis of the impacts of the proposed works on the environment. 4. New developments in higher lands The territorial studies should propose a new human settlement pattern, taking into consideration the existing vulnerabilities and the possible mitigation to the flood impacts on those areas. A detailed study will be carried out in order to identify high and safe areas suitable for the relocation of population residing in flood prone areas, considering two options: extension of existing settlement areas, and creation of new settlements. For the existing settlement areas:
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- Surveying of the land allocated for the relocation of population residing in flood prone areas. - Detailed design of the proposed extensions: new residential areas, including necessary services. - Improvement of existing general services: water supply, sanitation, electricity, sewerage system, including upgrading of oxidation ponds. For the new settlements; - Surveying of the land allocated for the relocation of population residing in flood prone areas. - Detailed design of the proposed extensions: new residential areas, including necessary services. 5. Relocation of vulnerable population The territorial studies should propose a new human settlement pattern, taking into consideration the existing vulnerabilities and the possible mitigation to the flood impacts on those areas. The population residing in flood prone areas, especially in the rural areas, will be relocated to higher and safer lands. In order to implement this process, will be necessary the identification of the prioritized areas, to establish a phased relocation process, as well as the verification of exact number of population residing in flood prone areas that need to be relocated For the implementation of the relocation process, it will be necessary the improvement of services (water supply, sanitation, electricity, sewerage system, including upgrading of existing oxidation ponds) in the existing selected settlements. The final step of this process will be a phased relocation of vulnerable population to the new areas once necessary services are constructed by stages. ! Compensation of traditional houses The implementation of the actions mentioned above will require the allocation of lands that belong to private people, so it will be necessary to create awareness among land owners about the importance to transfer land ownership to regional and local authorities in order to relocate population living in flood prone areas. During this process, an especial role will be played by the Traditional Leaders. The process will include the land valuation and actual compensation to land owners. ! Improvement of natural water ways The low capacity of the oshanas is one of the main causes of floods in the Cuvelai basin area, with high impact in the major urban and rural settlements. In order to avoid the continuance of these problems, it is recommended the improvement of the natural water ways (oshanas) to facilitate the water flow through those areas, mitigating the negative impacts on population and properties. The main construction activities in this process will be the deepening of rivers, removal of structures, debris, garbage and vegetation, as well as the improvement of local drainage within selected towns and settlements.
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A group of oshanas should been prioritized to be deepened to improve natural water flow through the following towns and settlements: Oshakati Town From (coordinates) To (coordinates) Distance Oshana XYXY(km) 1 457 100 8 041 600 459 100 8 028 100 15,30 2 459 100 8 041 800 457 900 8 007 000 37,20 3 464 100 8 038 800 460 300 8 020 900 19,90 4 463 400 8 035 700 464 800 8 006 500 30,40
Ongwediva Town From (coordinates) To (coordinates) Distance Oshana XYXY(km) 5 466 200 8 037 900 464 100 8 012 600 27,70 6 469 500 8 037 200 470 000 8 017 800 21,90
Helao Nafidi Town From (coordinates) To (coordinates) Distance Oshana XYXY(km) 7 477 600 8 076 100 481 400 8 055 800 22,00 8 480 300 8 076 100 482 100 8 055 700 22,60 9 482 900 8 076 100 486 100 8 056 100 21,20 10 483 900 8 076 100 486 400 8 058 400 22,10
Oshikuku Town From (coordinates) To (coordinates) Distance Oshana XYXY(km) 11 436 200 8 048 900 436 800 8 042 600 6,70 12 437 300 8 049 000 440 400 8 041 800 8,60
Okalongo Settlement Area From (coordinates) To (coordinates) Distance Oshana XYXY(km) 13 421 600 8 065 750 423 330 8 071 790 6,40
Outapi Town From (coordinates) To (coordinates) Distance Oshana XYXY(km) 14 384 108 8 055 480 390 876 8 065 370 13,10 15 386 640 8 058 750 392 482 8 064 160 8,50
Tsandi Settlement Area From (coordinates) To (coordinates) Oshana Distance XYXY 16 373 961 8 032 725 379 798 8 038 600 9,30
Onesi Settlement Area From (coordinates) To (coordinates) Oshana Distance XYXY 17 354 258 8 051 636 356 170 8 053 440 3,10
Omungwelume Settlement Area From (coordinates) To (coordinates) Oshana Distance XYXY 18 455 130 8 056 816 458 330 8 064 680 9,30
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! Construction of small hydraulic works The impact of the flood events during the rainy season in the Northern regions is not totally negative. These seasonal flows provide fishing grounds, renew pasture and recharge ground water supplies. Contradictorily, the rest of the year the territory is severely affected by drought and the lack of water is a serious concern for the population living in the area. Considering this situation, it is recommended the construction of small hydraulic works in selected places with the proper geographical and technical conditions to collect water for its use in agricultural activities, fishing and others during the dry season. ! Development of small scale tolerable agricultural activities Preparation of regional land use proposals for mostly affected geographical areas, considering green areas for the development of agriculture (short-term crops), woodlands, grazing lands, etc. At the same time, feasibility studies will be carried out for the development of small scale tolerable agricultural activities in areas where the shallow flood water remains for certain periods of time (rice fields, etc.) ! Rehabilitation of most affected roads and bridges A complete process of rehabilitation of the most affected roads and bridges should be implemented, taking into consideration the specific conditions of each area All the gravel roads and roads across the oshanas should be surveyed to determine the main streams and construct additional bridges to minimize washing away of road sections during heavy rains and floods. Implementation of construction activities to increase capacity of culverts and bridges to accommodate flood and storm waters in roads and gravel roads. Construction of protection works (reinforced concrete, stone walls) in areas with slopes of more than 30 % to avoid erosion process. Construction of new bridges and culverts in roads damaged by floods, with priority for areas affected by lack of accessibility during flood events. ! Rehabilitation of most affected sewerage systems Oxidation ponds with final water evaporation have proved to be vulnerable structures during flood events. Many of these systems break and/or overflow, spilling raw or insufficiently treated sewage into the surrounding, lower lying, densely populated areas, turning out to be a serious health hazard. Additionally, several sewerage pump stations are under water during the floods. To provide safer living conditions for the population living in areas at risk it is necessary to implement a process of rehabilitation of the sewerage systems, including oxidation ponds, pump stations, boreholes and reticulated network. In the major urban centers, the oxidation ponds should be replaced with modern biological treatment technology in the form of new single activated sludge plants, like the one that is proposed to serve both Oshakati and Ongwediva in a first phase, and Ondangwa in a subsequent stage.
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! Improve community participation in disaster management The Namibian government is working to strengthen its capacities to reduce the harmful effects of flood-related disasters in the future. A very important step in that direction will be the designing of disaster management policies from the ground up, involving emergency response committees at the local level, responsible to inform, organize, and train communities to prevent, cope with, and recover from those natural disasters. It is very important to recognize that risk is best managed in advance and at the local level, so it is necessary to support a new approach to risk management grounded in community participation. In the first place, it is required to carry out an overall vulnerability assessment in order to determine which areas (regions, constituencies, settlement areas, and towns) are most at risk from natural disasters, to select the ones where the project will be developed. The project should be highly participatory, aiming to develop community disaster committees and mitigation action plans. While grounded in the notion that disaster awareness and planning are best managed by local governments and by civic leaders, the project will also identify important roles for regional and national governments, NGOs, and private sector groups who can give support through technical know-how, information analysis, and early warning to community-based organizations. The project should be organized and supervised by Consultants with experience in disaster prevention and mitigation. The long-term objective of the project is to develop an informed and responsible community, capable of managing its own natural risks through active local participation in land-use planning, as well as in prevention and mitigation measures. Its first activity in a community is forming a local Disaster Mitigation Committee, representative of the community, to participate actively in the project and to disseminate its benefits. This committee is elected during a project launch workshop, which convenes community leaders, civic representatives, local leaders, and the public at large. A capacity-building activity starts immediately after the formation of the committee and includes a discussion on the meaning and implications of strategic planning and risk management. A risk-mapping workshop comes next, at which the committee locates areas prone to flooding on a large aerial photograph of the area. These zones serve as a basis for a more comprehensive hydrologic and geologic study that is then carried out separately by the Consultants. After discussing other risks and hazards with the community, supplemented by site visits and consultations with local focus groups, the Consultants combine the community information and the scientific data into a comprehensive risk map, which details the area’s physical, socioeconomic, and environmental vulnerability. This risk map also shows physical mitigation measures recommended by the community members and the Consultants, such as critical installations, lifeline infrastructure, and emergency shelters, existing or planned. In return for its participation, the community receives the final risk maps, which serve as a basis for discussions about local and regional development planning. The Consultants will carry out hazard analyses, which involve mapping vulnerability, identifying mitigation measures, prioritizing these measures, and creating action plans. The
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Consultants will also prepare long-term land-use plans that identify areas at risk and areas to be developed and appropriate actions to prevent developing settlements in vulnerable areas in the future. The project should also include an important component of regional and local planning, which aims at creating conditions that prevent natural events from becoming catastrophes. It consists of the participatory elaboration of an urban development plan, building on the risk map prepared in previous phases. This plan must, at minimum: 1. Include a regional development vision, 2. Specify possible uses of land consistent with the development objectives and the risks identified, 3. Define an implementation strategy, 4. Identify impact evaluation mechanisms and indicators, and 5. Describe updating procedures. One of the most important activities of the project will be the integration of the risk management and land-use planning, thereby creating the conditions for integrating real risk prevention into the development planning process instead of treating risk management as a separate issue. The final phase of the project will involve supporting communities in the identification and implementation of mitigation measures. Once the urban development plan is final, the local committees, assisted by the Consultants, will prepare Action Plans for Mitigation and Prevention. The plans will list and prioritize micro-projects to be carried out during the next ten years in each locality. These micro-projects can include structural measures like building retention walls, retrofitting shelter, or reforestation, and non-structural measures like conducting awareness campaigns or improving building codes. The participatory micro- planning process should allow for a clear sharing of responsibilities and a real involvement of communities. Construction and other implementation activities would then be carried out through community-based contracting. The vulnerability assessments will give local planning, by providing maps and a strategy for municipalities to plan their land-use and development programs. The role of national and regional government: Although community participation is essential to effective risk management before, during, and after natural events, some important activities cannot be carried out at the local level. Taking a national and regional perspective can generate greater efficiency and economies of scale. The types of activities to be carried out at the national level include technical analyses, emergency warning, and coordination of risk management initiatives. Main challenges 1. Preventive land-use plans, which take natural disaster impacts into account in defining land uses and, in particular, in designating land as unsafe for development, are the most powerful tools for disaster prevention. However, as is widely
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acknowledged in local development studies, plans are not enough. Frequently the land set aside as off-limits becomes a site for squatters and others who cannot afford the costs of living in planned developments. Therefore, preventive plans must be accompanied by an effective local system of enforcement if they are to work, and the best systems rely on community vigilance of areas at risk. Preventive plans must go beyond simply identifying land at risk; they should include locating suitable land to cover the range of needs of a growing settlement. The preventive approach is new to development planning and should be supported and watched over the coming years. Given the important differences in the level of land-use planning practices in each locality, it is already clear that a case-by-case approach will be needed to assure that risk prevention is fully integrated into local development planning. 2. Building partnerships takes time, and attempts do not always have a positive outcome. Moreover, communities are more receptive to physical measures than to capacity building, which may seem too abstract. In some urban areas, communities have become accustomed to receiving external assistance, especially following disasters. Thus, they can be reluctant to undertake risk management on their own. The lack of collective memory in new urban areas can also be an obstacle when trying to raise risk awareness. When community members have actually never experienced a natural disaster, it becomes harder to rouse their interest in prevention, particularly in the face of other basic needs, such as water, electricity, and transportation. 3. Daily problems of insecurity, unemployment, and insufficient social and physical infrastructure are much more threatening than a hypothetical flood event. Consequently, the history, particularities, and priorities of each community must be taken into account when trying to promote risk management at this level, or the community may simply not be receptive to any effort. Communities most vulnerable to natural events frequently have a disproportionately high number of illiterate members. Tools and strategies for training and capacity building must therefore be adapted so that all can participate. 4. Lastly, it can sometimes be tempting, for the sake of time and efficiency, to implement participatory projects directly at the community level without the intermediate participation of a committee. However, the sustainability of such an approach is questionable and most NGOs recognize that. Although building the capacity of a local committee to manage its own risks alone is very difficult, sustainable development requires such efforts.
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OSHANA REGION FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 232 Northern Regions. Flood Risk Management Plan 2011
6.3.2- OSHANA REGION
6.3.2.1 – Regional Proposals The main recommended action for the Region is the implementation of the Concept Master Plan prepared for the Oshakati town. The Concept Master Plan comprises a large number of proposals and actions that will require a vast amount of financial support and time. Nevertheless, it is possible, and recommended to start the execution of a group of tasks and activities that will facilitate the future implementation of the whole Concept Master Plan in perfectly timed phases. According to this, it is possible to identify within following activities: Activity 1: Compensation of traditional houses. The areas within the proclaimed townlands located on the northern side of the town, mostly high lands, are still occupied by traditional houses (homesteads) and communal farms. There is an urgent need to complete the legal process to facilitate the compensation of the land owners and make the areas available for the future town development, in especial to relocate the population living in flood prone areas. Activity 2: Environmental Impact Assessment. The implementation of the Master Plan requires an exhaustive analysis of the impacts of the proposed works on the environment. Activity 3: Servicing of extensions 4, 5, 6 and Ekuku area. With the purpose of allow the relocation of population living in vulnerable areas to flood events, it is essential to provide in advance the required technical infrastructure (water supply, sewerage, electricity, roads and drainage) to the land allocated to that purpose, in this case the extensions 4, 5, 6 and the Ekuku area. Activity 4: Relocation of vulnerable population. Once the necessary conditions are completed in the zones designed for new residential developments in the north side (extensions 4, 5, 6 and Ekuku area), it will be possible to initiate the gradual relocation of the residents in flood pone areas, ensuring that no unplanned development should be permitted in those places, especially the settlement of new population. Activity 5: Deepening of the Okatana River (oshana). This activity will comprises the information gathering, design, tender and carrying out of the necessary works in order to improve the natural water way to facilitate water evacuation and mitigate damages to nearby areas. The proposal could include the identification and removal of constructions located in the area under project. Activity 6: Modification of Kandjengedi and Sky bridges. This activity will comprises the information gathering, design, tender and construction activities to increase capacity of both bridges to accommodate flood and storm waters.
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Activity 7: Expansion of two lanes road until Ongwediva. The enlargement of the Kandjengedi Bridge should consider also the increase of the road section (two lanes) in order to improve the traffic flow, considering this expansion along the main road from Oshakati to Ongwediva, improving the connection between these two major urban areas. Activity 8: Construction of a new activated sludge treatment plant. Oxidation ponds with final water evaporation have proved to be vulnerable structures during flood events. Many of these systems break and/or overflow, spilling raw or insufficiently treated sewage into the surrounding, lower lying, densely populated areas, turning out to be a serious health hazard. Additionally, several sewerage pump stations are under water during the floods. To provide safer living conditions for the population living in areas at risk, especially in the major urban centers, the oxidation ponds should be replaced with modern biological treatment technology in the form of a new single activated sludge plant, which will serve both Oshakati and Ongwediva in a first phase, and Ondangwa in a subsequent stage. Activity 9: Construction of the dike around town proposed by the Master Plan: To avoid future flooding, a 45km long and 2m high dike with an integrated 4 lane road needs to be constructed around the existing town with controlled locks and an adequate buffer zone below the urban area. The ring road will also protect the town centre from heavy and through - traffic. The natural rivers inside the town will be channeled and will have a controlled water level year-round. The designed dike protects also Ongwediva from the flooding water. For the rest of the Region, the main recommendations are: 1. Influence of river overflows. ! Increase the transversal section of the rivers and their main tributaries. ! Control the overflow in the riverbanks of rivers and main tributaries by means of dams. ! Define waters evacuation points from the rivers. ! Starting from evacuation points of alluvial waters to build Canals Systems that allow the water to pass through until the Etosha Pan in order to preserve the Ecological Balance. 2. Influence of land topography. ! Allow the waters to pass through. ! Whenever it is possible, to limit the expansion of flood waters outside of oshanas’ limits by means of earth dams. ! Define where to accumulate part of the flood waters to guarantee its further use.
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3. Intensity of rains. ! Take into account, for further plans, the annual historical average of rainfall and its maximum characteristic values (50 years behind or more) to define the perspective development of Towns and Settlements. 4. Influence of roads’ characteristics. ! Whenever it is necessary, to elevate road levels to keep the flood waters from surpass them and destroy their section. ! Take into account flood waters’ natural lines of flow, according to land topography, to locate the culverts through the roads. ! Whenever it is necessary, to increase the number of culverts in those places where they are located to guarantee the waters pass through. ! Whenever it is necessary, to increase the bridge dimensions and elevate their circulation board levels to guarantee the waters pass through and to avoid the waters pass on them. 5. Influence of drainage characteristics in towns and settlements. ! Build gutters (canals) with appropriate slopes to force the water circulating through the necessary way. ! Build kerbs in all paved roads of urban areas. ! Build gutters (channels) in all not paved urban roads. 6. Influence of informal settlements. ! Avoid informal settlement constructions. ! Establish construction limits to avoid the housing proliferations in oshana areas. ! Elevate floor levels in all housings and buildings. 7. Physical Planning Influence in Perspective Town and Settlement Development. ! Increase and improve all the studies and analysis for Perspective Town and Settlement Development taking into account topographical conditions, rain behavior and intensity and frequency of flood avalanches. 8. Influence of the location of crop fields ! Redefine the location of crop fields taking into account the influence of the floods. ! Guarantee a correct location of drainage systems in crop fields which allows an appropriate humidity level in them and avoid water accumulations. 9. Influence of indiscriminate construction’s arid extractions. ! Avoid sand extraction in low areas, near to bridges, roads and urban areas. ! Establish specific areas for construction’s arid extractions.
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ONDANGWA TOWN FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 236 Northern Regions. Flood Risk Management Plan 2011
6.3.2.2- Ondangwa Town Proposals During storm water, the situation in Ondangwa is dramatic due to massive amount of water on the low-lying areas. Hundreds of houses are under water. In general, town sanitation is badly affected by the flooding thus in some extensions there are not working sanitation system at all. Due to low level of sewerage manholes, storm water is ussually mixed up with sewerage water by creating a serious health risk to the people living nearby. While storm water is entering the sewerage network, oxidations ponds are filling rapidly causing them to overflow to the nearby pools of water (oshanas). Also roads are washed away and communities are isolated on islands in the middle of pools of water. The Development Proposals for the town will consider the identification of four major sectors, as well as the flood prone areas: Sector 1. - Existing urban area. Sector 2. - Northeastern area. Sector 3. - Southwestern area. Sector 4. - Northwestern area Land Use Proposals: Sector 1: For the existing urban area, it is necessary the completion of the vacant land located within the sector, including infrastructural solutions, specially the storm water drainage system. The most important actions to be implemented in the sector are: Nursery-Military Base watercourse: One of the key activities was to open a drainage route from the northern side of the road to the southern side, starting at the Nursery behind the Open Market. Firstly, two channels were excavated in informal settlement west from Oluno. The idea was to connect the Central Oshana to the Military Base Oshana; however, the longer channel was not very successful for carrying water in long run due to unfavorable topography of the area. Shorter channel has been very effective and it has connected the two oshanas fluently, although water is flowing on the street in the informal settlement, which has not been the intention.
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Market area: Existing concrete storm water channel was rehabilitated and a trench was excavated in the middle of the Market. These two channels were connected to the Central Oshana. To allow water flow from northern side of the main road, both box culverts under the main road were cleaned. Furthermore, all small mm 200 diameter concrete pipes under the road to the Nursery were opened and the existing trench on the side of the Open Market buildings was reopened. The water level seems to remain and no further flowing is occurring through the culverts under the main road. Natural explanation for this is unsuitable topography of the area and poor connection route from Open Market to pool in front of the main road. The oxidation ponds and nearby areas: After heavy rains, new oxidation ponds started overflowing forming a big pool of water (the Prison Oshana) between the two roads to Olukonda and the road coming from the Military base. In addition, overflowing water has been flowing through the refuse dump, following the road to north-west towards the town. During the flood, refuse dump road was blocked with a 1,5 m high wall of sand. Additionally, two small channels were excavated to the eastern side of the road, in order to divert the water to the nearest old empty oxidation ponds. In order to stop overflowing, eastern walls of the hexagon shaped evaporation pond was fixed by leveling the sand walls higher. Some days ago, started pumping water with a mobile pump to the old (still empty) oxidation pond. Furthermore, three connection channels were excavated between the Prison Oshana and the next downstream oshana. Chico’s channel: First movement was to open the culvert under the main road opposite of the Chico’s building. Oluno’s low-lying areas: The situation in Oluno Extension 1 has been complicated hence suitable drainage route cannot be found. The whole area is lying in a pit and nearby oshanas are far away thus excavating traditional gravity based channels would not be easy to realize. To relieve the situation, a mixed combination of temporary pipeline and excavated channel was constructed from the main pool of water to the Central Oshana. Water was pumped over the high ground with a mobile pump. General work: Additionally, small channel was excavated in front of Metro and blockage was removed from the eastern NamWater channel to allow water move more easily. Conclusions: Emergency measures have relieved the situation only at the nearby areas to the Nursery-Military Base drainage route. Instead, other areas are still and will be suffering in the future if the necessary emergency and longer-term measures will not be put in place. Situation is dangerous especially in the areas where the sanitation system is crippled due to non-working pump stations and overflowing sewerage network. The situation is challenging in every possible way. For some areas, such as Extension 1 and Extension 6, which are low- lying areas, is difficult to find suitable drainage paths. In any case, drainage channels have to be long and pumps are needed. To make the situation even worse, existing storm water channels under the main roads are only few and their capacity is already limited. In general, the whole storm water system is under dimensioned for the current and future need.
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Permanent drainage routes: When dry season begins and most of the water has gone, opened drainage routes have to be strengthened and protected from erosion. Routes, which are considered permanent solutions, have to be also enlarged so that their capacity is sufficient for future development and exceptional situations. At this point, Nursery-Military Base drainage route and Chico’s channel can be identified as permanent routes. Behind Military Base and road to Uukwiyo existing culverts have to be replaced with bigger, at least, 750 mm concrete pipes (3-4 pipes for each crossing) to multiply the current flow capacity to downstream oshanas. Chico’s channel has to be equipped with concrete ceilings and channels have to be excavated in Uupopo to connect Chico’s channel to the Central Oshana. (See graphical approach from Appendix 1). Extension 6: To solve the flooding situation in Extension 6, residential plot levels should be raised near the Eagle pump station by using construction wastes (sand, stones, concrete, pieces of bricks etc.). After fill material has been laid on the ground, it should be compacted and layered flat. Draining the area is complicated due to unfavorable topography. A ground level survey should be executed to figure out how water could be diverted to the eastern NamWater channel and through that to the NamWater dams. Drainage route can be realized, it is wise to use existing undeveloped flooded areas as storm water basins in the future. These areas should be deepened and excavated material should be used for elevating residential plots. Water should be diverted to these dams by roadside channels and culverts under roads. To prevent contamination with sewerage water, existing sewerage should be cut off from these areas. Other option is to raise sewerage manhole covers on top of the water level. Eagle pump station should be protected from future flooding by raising the ground level around the station. Shiweda’s area: Pool of water around Shiweda pump station has to be directed through the main road to the Central Oshana. The problem is that, the bottom level of the culvert is higher than the surrounding ground level. This has caused the water to dam up behind the culvert and only a very slow flow of water occurs through the channel. Bottom level of the culvert has to be lowered but in the meanwhile mobile pump can be used to get water moving. Another possibility is to use existing NamWater channel to drain water to NamWater’s dams but firstly, dams’ filling rate has to be monitored once water from Extension 6 has been diverted there, too. Oluno’s low-lying areas: The situation in Oluno is difficult. First of all, ground level survey must be executed before any improvements can be done. Currently, water around Shindabe pump station has been directed to the Central Oshana as is described. Okangwena: There is a possibility to divert water from the informal settlement to an oshana to east. In order to develop this area in the future, proper storm water drainage is needed although that may cause some of the buildings to be removed. NamWater area: Normally, water was pumped from two small collection basins to the big dam in the middle. In case of overflow, small basin southern side of the big dam handled the overflowing water. Currently pump stations are not working and the big dam receive only
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Northern Regions. Flood Risk Management Plan 2011 rainwater although its capacity would accommodate a lot more water. In a critical situation rainfall has made the western collection basin to overflow causing serious flooding in the western areas. For example, NamWater reservoirs have been unreachable from the west for a long time. Therefore, it is recommended to figure out if the pump stations are repairable, thus water could be lifted to the big dam. It would ease the situation immediately in the nearby western areas. Sectors 2, 3: Planning of the future development areas of the town, including infrastructural solutions, specially the storm water drainage system. Sector 4: Restricted development due to the presence of airport facilities. Immediate implementation steps and emergency measures: diverting sewage water to the old empty oxidation ponds and using both treatment lines of the new oxidation ponds can be probably evaded and potential health risk will stay at minimum level. Emergency measures are based on the idea that water ought to flow freely through the town. Also emergency measures should be put in place in downstream, so that there is space for water coming from upstream. Pools of water must be connected each other by channels and culverts. Short-term measures: When dry season begins, these newly built or renovated drainage channels have to be also strengthened and protected from erosion. Longer-term measures: A network of properly built flow channels and pump extensions should be constructed to ensure that buildings that have been already erected in low-lying areas are protected from flooding in the future. Despite the provision of well-defined new drainage channels as primary waterways, the oshana basins must be retained to serve as flood plains for storing any excess floodwater, meaning that some of the plots must be left unconstructed. Flood Prone Areas: For the flood prone areas farther regulations will be established, which shall apply to all lands within the existing urban area in the floodways or flood prone areas within the zoning jurisdiction of the town of Ondangwa that are subject to a one percent or greater chance of flooding in any given year.
The degree of flood protection required by these regulations is considered reasonable for regulatory purposes and is based on engineering and scientific methods of study. Larger floods may occur on rare occasions or the flood height may be increased by man-made or natural causes, such as ice jams and bridge openings restricted by debris.
Compliance with these regulations does not imply that lands outside a floodplain or flood prone areas or uses within such areas will be free from flooding or flood damage.
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6.3.2.2.2- Ondangwa Town. Contingency Plan Ongdanwa Town is located in a very flat geographical area. Presence of main natural water courses (oshanas) in surrounding areas (running from north to south in the entire town).
All these elements are affected by flood because of water coming from Cuvelai basin and heavy rainfall. Most of the towns areas are affected, the flood water cover the flood prone areas and main access roads interrupting accessibility to some vital services (hospitals and private clinics, schools, shops, etc) and other human settlements located nearby (Oshakati and Ongwediva).
Scenario for planning purpose ! Hazard and resulting emergency Ongdanwa town is affected during the rainy season by floods as consequences of heavy rainwater that inundate principally low lying areas within town boundaries and the overflow of the oshanas that surrounding the south and north parts of the town, due to the high volume of water coming from the Cuvelai basin. The emergency stated is only proclaimed by the central government. ! Likely triggers g) Early warning indicators and triggers: They are not an early warning system. The initial warnings come from the news by TV about heavy rains at neighbor countries and some information from a Central Office of the Ministry of Agriculture and for National Meteorological forecast h) Continuous heavy rains in the area i) Also from INTERNET about climate and meteorological conditions in the south part of African Continent. Nevertheless, sometimes appears news at national newspaper, like in Namibian of January 18 / 2011: j) Responsible for monitoring the early warning indicators and triggers: The Town Chief Executive Officer (CEO) is the maximum responsible for monitoring the early warnings, although there is a Town Council’s official directly responsible with that assignment (Mr. Kahenge – focal point). The Civil Defense Committee is activated during emergency conditions. ! Risk analysis g) How likely is this scenario to occur? Despite of the fact that drought is the most common natural hazard to the majority of the country, during every rainy season (November – April) the area where Ongdanwa town is located, becomes very vulnerable to flood events in a process that has seen a recurrence during the last three years.
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The above – normal and/or high inflows in the Cuvelai basin or the combination of both natural phenomenon is a potential threat to the area, which experienced the worst flood disasters during last period as part of the global climate change. h) What will be the consequences should the scenario occur? The flood disasters cause damages and losses to the public and private sectors (public health and education facilities, housing business, infrastructure and others). The most terrible is the loss of human lives due to drowning and attack by wild life animals. The productive sector (agriculture, commerce – trade and markets) is highly affected (lost of crops production, commercial products, etc.). The population living on most vulnerable areas should be relocated to safer areas, requiring emergency humanitarian support (food, clothes, shelter, water and others). Normal life are disrupted, as some persons cannot come back to their normal place of living and cannot continue with their normal business of carrying a living (jobs loss, crops destroyed, or place of work destroyed). At the same time, people don’t have access to basics needs and services. As a result of that fact, is possible to obtain the following table: Ongdanwa Town. Table of existing vulnerability in the town: Total Total of Total Kind of Hazard Vulnerability Vulnerability Vulnerability surface of housing population hazards level surface population household settlement High / Ha. # Hab. XXX Middle Ha. % Hab. % # % 10 Storm High 313,2 24,0 22,5 1 941,0 22,0 1 305,0 8 823,0 45 000 water 125,0 flooding Middle 274,1 21,0 9 225,0 20,5 1 782,2 20,2 18 High 561,2 43,0 42,0 3 573,3 40,5 1 305,0 8 823,0 45 000 Drought 900,0 Middle ------
The main consequences should the scenario occur are: - Most of the businesses and commercial buildings are flooded. - Contamination of the superficial and underground water due the overflow of some wells and septic tanks located in some parts of the town and overflow of the oxidation ponds. - Some roads are interrupting, preventing the access to some areas, especially to the informal settlements. - Lack of accessibility to some basics social services (schools, clinics, food and other basic services). - Relocation of affected population to the safer places into the town or in other high places.
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! Population at risk Most of the population residing in Ongdanwa town is at risk during a flood event, especially those living near the flood prone areas (informal settlements, and low lying areas). There is not exact idea of the total amount of people at risk, but could be more than 20 000 Hab. (almost the 40% of the town). Specific vulnerable people to be relocated: Disabled persons, old person and children. If you must evacuate in the event of a flood: ! Always follow the instructions of local emergency officials. ! Take your personal emergency grab-and-go kit with you. This kit should have basic essential items such as prescription medications, eye glasses, important papers, flashlight, battery powered radio, clothing, identification and some cash. ! Ensure each family member has waterproof clothing and footwear. ! Shut and lock doors and windows, including barn doors and gates. Shut off water supply, natural gas and power to all buildings, barns, etc. as identified on farm map. ! If you are evacuating your premises, shut off your gas valve at the meter. ! Rendezvous with family and workers at designated safe meeting place or at local Emergency Services Shelter. ! Anticipated duration of emergency conditions The duration of emergency conditions depends on the weather characteristics and conditions (meteorological situation – duration and intensity of rains, volume of flood water, etc.) and on the capacity of resilience of this geographical area. ! Budget and other resources to face up to the disaster It don’t exist any special government warehouse with food supply for the affected people, but in emergency cases is used some strategic reserves from the Central Government and of some buildings belonging of Regional Council. The budget for the town in case of some kind of disaster is about $40,000 NAD. This budget should include capacity building, training and some additional information for the people in town. Vulnerable people at the town must be relocated at safes houses: Ongdanwa Community Hall and traditional authority buildings and schools. Also in a relocation camp (an area near the airport). All the people who live in tents need time to rebuild their houses. They have officially 8 means of transportation. Main Objectives: ! Saving lives ! Preserving assets ! Preventing Mass Migration
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! Ensuring access to public services for all the people ! Establishing conditions for restoring of self - reliance ! Minimize damage resulting from emergency situation Program Implementation: ! Immediate Response and Evacuations Routes When the disasters appear in this town, many others means of transportation are designated for help the affected people. Some means from certain local business, private tracks and another soften transports are very useful for many critical situations. Tarred roads are used as principal way of transportation because are safer ways. Nevertheless, most of the roads are not tarred (gravel) so they are very affected by floods with problem of accessibility principally in informal settlements. Also all of roads are affected by strong erosion that is able to destroy them. After flooding is developed a campaign in order to avoid some very often diseases like cholera, malaria, dengue, etc. that could became in a very serious epidemics. ! Long term plans In Ongdanwa, they haven’t any rescue team (just the normal employers of the office of town council), or Red Cross organization and neither firefighter. It also doesn’t have any educative or informational program to prepare and train a lot of people to confront these natural hazards, like flooding. ! Preparedness and Maintenance Actions A Plan will be updated and revised systematically and it is necessary to prepare some simulation exercises to test the plan and also a proper preparation and capacitation in order to avoid big quantities damages. Major existing restrictions: 1. Inadequate skilled and trained staff in disaster management in Town Council 2. Lack of Town Contingency Plan 3. Disaster management considered an add on activity by Town Council 4. Lack of clear understanding of roles and responsibilities among stakeholders, even among members of the Civil Defense Committee 5. Lack of clear guidelines on disasters management procedures (early warning system) 6. Insufficient financial allocation/contingency fund for disaster management 7. Inadequate warehouse space 8. Poor public awareness on flood issues.
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Participants and partnerships in contingency planning. Ondangwa Town Council, Home Affairs, Business owners, NORED, NAMPOL, NAMWATER, Schools, etc. Early Warning System: ! Strengthen sharing disasters information locally and transboundaries ! Engaged traditional leaders in informatics sharing and dissemination in infrastructural development ! Improve channels of communicating the early warning system results to relevant authorities ! Channel information dissemination trough relevant authorities. At regional level however, the Namibian Disaster Management System (NDMS) appointed two senior people to oversee the coordination of the disaster response. The roles of the two senior officers were among others to: ! Provide a link between disaster response operational levels with the NDMS through weekly report to the Secretary to Cabinet (Chairperson of the National Emergency Management Committee) ! Received donations and facilitate timely distribution to the flood affected ! Continuously monitor the flood situation and facilitating the provision of appropriate response ! Coordinating transport and logistic ! Conducting weekly meetings on the flood disaster response with stakeholders ! Providing media briefs on the flood situation ! Developing medium and long term recommendation for effective flood management and rehabilitation And also, ! The Regional Councils should consider disaster management as an integral part of their activities and not an add on activity and responsibilities given to staff that have other key roles to play in the Regional Councils. ! Regional Emergency Management Units need to be continuously proactive and sensitive to the disaster risk management and should strengthen coordination among all the stakeholders before, during and after disasters. ! To facilitate coordination of disaster risk management activities (preparedness and contingency planning, public awareness, secretariat for the regional council disaster technical committee, beneficiary registration and tracking and monitoring supplies of food and not - food distribution), Regional Council should be encouraged to fill the positions of Regional Disasters Management Coordinators.
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Some solutions to the flood problem: Floods are a consequence of natural hydro-meteorological phenomenon, combined with their interaction with the catchment characteristics. Through interventions in changing the characteristics of the catchment the run-off processes can be altered, thereby making it possible to reduce the magnitude of the flood hazard thus generated. Urban drainage systems, made up of channels, culverts, sewers etc., are meant to prevent local floods by conveying storm water away from vulnerable sites. Mostly this is done with the aim of draining storm water as fast as possible out of town. This practice may be benign in coastal cities or in agglomerations with no exposed living spaces downstream, but if cities or urban districts upstream of other riverside settlements drain storm water too quickly, this may cause urban floods downstream. Thus the sustainable urban drainage systems aim for adequate, but not too excessive, drainage in order to mitigate local floods, without creating new hazards downstream. Commonly it presents two major concepts of urban storm drainage: direct runoff versus source control. The latter concept suggests a number of so-called “source control measures” which are meant to either retain or reduce storm water runoff in order to prevent the exceedance of the drainage system and to mitigate the generation of flood hazards downstream. The resulting hydrographs illustrate how the reduction and retention of storm water runoff in a source control drainage systems can cut discharge peaks. The reduction of surface runoff in absolute terms can be achieved by a variety of measures that increase infiltration, evaporation and/or transpiration from the catchment areas that contribute to local flooding. The easiest way to do so is to preserve unsealed and greened spaces in the city. Such spaces are of multifunctional purpose, they: Reduce surface runoff by increasing infiltration and evapotranspiration; Retain water through interception; Filter the percolating water; Recharge groundwater resources; Reduce air pollution and improve the urban microclimate; and Can be used for recreational purposes in the form of parks and gardens. Since the availability of space is highly limited in cities, less extensive measures that enable effective in-town infiltration can also be used. Among them are: Infiltration trenches; Soak-aways; and Measures that increase the permeability of larger surfaces. Essentially, infiltration trenches and soakaways consist of a trench or a pit filled with a top layer of permeable material like crushed stones or gravel and a bottom layer of sand. Since the potential for in-town infiltration and evapo-transpiration is limited, especially in cities where convective precipitation and non-absorptive soils prevail, measures of storm water retention are vital for the mitigation of urban floods as well as for the prevention of
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 246
Northern Regions. Flood Risk Management Plan 2011 downstream floods. Storm water retention can be achieved or facilitated by constructing basins or ponds that temporarily store surface runoff and release it subsequently at a controlled rate. There is a variety of retention basins and ponds - open or covered, wet or dry, online or offline – that may serve various purposes. The advantage of multipurpose dry ponds is the maximization of land use. They can also contribute to infiltration and to the removal of pollutants. There are many creative possibilities to use the same space for everyday activities as well as for occasional flooding. Furthermore, wet ponds in the form of artificial lakes can be of aesthetic value. Temporary storm water retention can be made in sport courts, parking sites, playgrounds etc. In all cases sedimentation has to be considered a likely problem in basins and ponds. These retention basins require flow equalization facilities to prevent flooding of and damage to such facilities. Although unfiltered storm water is normally not of drinking water quality, it is amenable for non-potable purposes such as washing, irrigation, toilet flushing etc. Storm water is usually collected on roofs and stored in tanks or in underground cisterns. Implementation: The purpose of this plan is to inform and guide all the local stakeholders in the undertaking of its planning responsibilities, and in integrating and coordinating the activities of different agencies that influence the use and development of land that may be affected by natural hazards. The plan will also guide local governments, other agencies and state government of those aspects of state planning policy concerning natural hazard mitigation that should be taken into account in planning decision-making. There are many agencies that have the power to permit development that may be subject to natural hazards. While recognizing these responsibilities, this plan provides a checklist to enable the delivery of a consistent approach to natural hazard mitigation.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 247
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 248
Northern Regions. Flood Risk Management Plan 2011
ONGWEDIVA TOWN FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 249 Northern Regions. Flood Risk Management Plan 2011
6.3.2.3- Ongwediva Town Proposals The town is not seriously affected by flood events, but some areas become isolated during flooding. Some new residential areas are affected due to inadequate storm water solutions. The town lands located in the southern, eastern and western parts are low lying areas. Future development should be to the northern part of the existing town lands, so a new Comprehensive Town Scheme should be prepared considering environmental issues, as well as the relationship with Oshakati town and the possibility of a future merge. The Development Proposals for the town will consider the identification of three major sectors, as well as the flood prone areas: Sector 1. - Existing urban area. Sector 2. – Scattered high lands located on the South, East and West of the existing urban area. Sector 3. - Northern area (future extension area). Land Use Proposals: Sectors 1, 2: Completion of the vacant land located within the sectors, including infrastructural solution, specially the storm water drainage system. Sector 3: Planning of the future development areas of the town, including infrastructural solutions, specially the storm water drainage system. Flood Prone Areas: For the flood prone areas farther regulations will be established, which shall apply to all lands within the existing urban area in the floodways or flood prone areas within the zoning jurisdiction of the town of Ongwediva that are subject to a one percent or greater chance of flooding in any given year.
The degree of flood protection required by these regulations is considered reasonable for regulatory purposes and is based on engineering and scientific methods of study.
Larger floods may occur on rare occasions or the flood height may be increased by man- made or natural causes, such as ice jams and bridge openings restricted by debris.
Compliance with these regulations does not imply that lands outside a floodplain or flood prone areas or uses within such areas will be free from flooding or flood damage.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 250
Northern Regions. Flood Risk Management Plan 2011
6.3.2.3.2- Ongwediva Town. Contingency Plan Ongwediva Town is located in a very flat geographical area. Presence of main natural water courses (oshanas) in surrounding areas (running from north to south in the entire town).
All these elements are affected by flood because of water coming from Cuvelai basin and heavy rainfall. Most of the towns areas are affected, the flood water cover the flood prone areas and main access roads interrupting accessibility to some vital services (hospitals and private clinics, schools, shops, etc) and other human settlements located nearby (Oshakati and Ongdanwa).
Scenario for planning purpose ! Hazard and resulting emergency Ongwediva town is affected during the rainy season by floods as consequences of heavy rainwater that inundate low lying areas within town boundaries and the overflow of the oshanas that surrounding the south and north parts of the town, due to the high volume of water coming from the Cuvelai basin. The emergency stated is only proclaimed by the central government. ! Likely triggers k) Early warning indicators and triggers: They are not an early warning system. The initial warnings come from the news by TV about heavy rains at neighbor countries and some information from a Central Office of the Ministry of Agriculture and for National Meteorological forecast l) Continuous heavy rains in the area m) Also from INTERNET about climate and meteorological conditions in the south part of African Continent. Nevertheless, sometimes appears news at national newspaper, like in Namibian of January 18 / 2011: n) Responsible for monitoring the early warning indicators and triggers: No person in the Town Council is responsible for monitoring the early warning indicators. It is a share responsibility by the Head of Civil Defense of Ongwediva Town Council (Focal Point), the councilors of affected constituencies and the Emergency Committee of this Town Council made up by stakeholders from different institutions and organizations. ! Risk analysis i) How likely is this scenario to occur? Despite of the fact that drought is the most common natural hazard to the majority of the country, during every rainy season (November – April) the area where Ongwediva town is located, becomes very vulnerable to flood events in a process that has seen a recurrence during the last three years. The above – normal and/or high inflows in the Cuvelai basin or the combination of both natural phenomenon is a potential threat to the area, which experienced the worst flood disasters during last period as part of the global climate change.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 251
Northern Regions. Flood Risk Management Plan 2011
j) What will be the consequences should the scenario occur? The flood disasters cause damages and losses to the public and private sectors (public health and education facilities, housing business, infrastructure and others). The most terrible is the loss of human lives due to drowning and attack by wild life and crocodiles. The productive sector (agriculture, commerce – trade and markets) is highly affected (lost of crops production, commercial products, etc.). The population living on most vulnerable areas should be relocated to safer areas, requiring emergency humanitarian support (food, clothes, shelter, water and others). Normal life are disrupted, as some persons cannot come back to their normal place of living and cannot continue with their normal business of carrying a living (jobs loss, crops destroyed, or place of work destroyed). At the same time, people don’t have access to basics needs and services.
As a result of that fact, is possible to obtain the following table: Ongwediva Town. Table of existing vulnerability in the town:
Total Total of Total Kind of Hazard Vulnerability Vulnerability Vulnerability surface of housing population hazards level surface population household settlement High / Ha. # Hab. XXX Middle Ha. % Hab. % # % 1 347.5 12,0 4,0 189,0 4,0 High 000,0 2 896 4 379,0 27 000,0 Storm water flooding 463.4 16,0 2 500,0 9,0 472,0 11,0 Middle 10 1 361,1 47,0 39,0 919,6 21,0 High 530,0 2 896 4 379,0 27 000,0 Drought ------Middle The main consequences should the scenario occur are: - Most of the businesses and commercial buildings located along the border of the oshanas, including the lodges. - Contamination of the superficial and underground water due the overflow of some wells and septic tanks located in some parts of the town and overflow of the oxidation ponds. - Some roads are interrupting, preventing the access to some areas, especially to the
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 252
Northern Regions. Flood Risk Management Plan 2011
informal settlements. - Lack of accessibility to some basics social services (schools, clinics, food and other basic services). - Relocation of affected population to the safer places into the town. ! Population at risk Some of the population residing in Ongwediva town is at risk during a flood event, especially those living near the flood prone areas (principally informal settlements, and low lying areas). People who live here are affected especially due to the lack of accessibility during floods events, as well as some planned areas (Extension 12, 16 and 17) because of the lack of proper drainage solution that allow the free flow of water. There is not exact idea of the total amount of people at risk, but could be more than 3 500 Hab. (the 15% of the town). Specific vulnerable people to be relocated: Disabled persons, old person and children. If you must evacuate in the event of a flood: ! Always follow the instructions of local emergency officials. ! Take your personal emergency grab-and-go kit with you. This kit should have basic essential items such as prescription medications, eye glasses, important papers, flashlight, battery powered radio, clothing, identification and some cash. ! Ensure each family member has waterproof clothing and footwear. ! Shut and lock doors and windows, including barn doors and gates. Shut off water supply, natural gas and power to all buildings, barns, etc. as identified on farm map. ! If you are evacuating your premises, shut off your gas valve at the meter. ! Rendezvous with family and workers at designated safe meeting place or at local Emergency Services Shelter. ! Anticipated duration of emergency conditions The duration of emergency conditions depends on the weather characteristics and conditions (meteorological situation – duration and intensity of rains, volume of flood water, etc.) and on the capacity of resilience of this geographical area.
! Budget and other resources to face up to the disaster It don’t exist any special government warehouse with food supply for the affected people, but in emergency cases is used some strategical reserves from the Central Government and of some buildings belonging of Regional Council. The budget for the town in case of some kind of disaster is about $30,000 NAD. This budget should include capacity building, training and some additional information for the people in town.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 253
Northern Regions. Flood Risk Management Plan 2011
Vulnerable people at the town must be relocated at safes houses: traditional authority buildings and schools. All the people who live in tents need time to rebuild their houses. They have officially 6 means of transportation. Main Objectives: ! Saving lives ! Preserving assets ! Preventing Mass Migration ! Ensuring access to public services for all the people ! Establishing conditions for restoring of self - reliance ! Minimize damage resulting from emergency situation Program Implementation: ! Immediate Response and Evacuations Routes When the disasters appear in this town, many others means of transportation are designated for help the affected people. Some means from certain local business, private tracks and another soften transports are very useful for many critical situations. Tarred roads are used as principal way of transportation because are safer ways. Nevertheless, most of the roads are not tarred (gravel) so they are very affected by floods with problem of accessibility principally in informal settlements. Also all of roads are affected by strong erosion that is able to destroy them. After flooding is developed a campaign in order to avoid some very often diseases like cholera, malaria, dengue, etc. that could became in a very serious epidemics. ! Long term plans In Ongwediva, they haven’t any rescue team (just the normal employers of the office of town council), or Red Cross organization and neither firefighter. It also doesn’t have any educative or informational program to prepare and train a lot of people to confront these natural hazards, like flooding. ! Preparedness and Maintenance Actions A Plan will be updated and revised systematically and it is necessary to prepare some simulation exercises to test the plan and also a proper preparation and capacitation in order to avoid big quantities damages. ! Major existing restrictions: ! Inadequate skilled and trained staff in disaster management in Town Council ! Lack of Town Contingency Plan ! Disaster management considered an add on activity by Town Council ! Lack of clear understanding of roles and responsibilities among stakeholders, even among members of the Civil Defense Committee
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 254
Northern Regions. Flood Risk Management Plan 2011
! Lack of clear guidelines on disasters management procedures (early warning system) ! Insufficient financial allocation/contingency fund for disaster management ! Inadequate warehouse space ! Poor public awareness on flood issues. ! Participants and partnerships in contingency planning. Ongwediva Town Council, Home Affairs, Business owners, NORED, NAMPOL, NAMWATER, Schools, etc. Early Warning System: ! Strengthen sharing disasters information locally and transboundaries ! Engaged traditional leaders in informatics sharing and dissemination in infrastructural development ! Improve channels of communicating the early warning system results to relevant authorities ! Channel information dissemination trough relevant authorities. At regional level however, the Namibian Disaster Management System (NDMS) appointed two senior people to oversee the coordination of the disaster response. The roles of the two senior officers were among others to: ! Provide a link between disaster response operational levels with the NDMS through weekly report to the Secretary to Cabinet (Chairperson of the National Emergency Management Committee) ! Received donations and facilitate timely distribution to the flood affected ! Continuously monitor the flood situation and facilitating the provision of appropriate response ! Coordinating transport and logistic ! Conducting weekly meetings on the flood disaster response with stakeholders ! Providing media briefs on the flood situation ! Developing medium and long term recommendation for effective flood management and rehabilitation And also, ! The Regional Councils should consider disaster management as an integral part of their activities and not an add on activity and responsibilities given to staff that have other key roles to play in the Regional Councils. ! Regional Emergency Management Units need to be continuously proactive and sensitive to the disaster risk management and should strengthen coordination among all the stakeholders before, during and after disasters.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 255
Northern Regions. Flood Risk Management Plan 2011
! To facilitate coordination of disaster risk management activities (preparedness and contingency planning, public awareness, secretariat for the regional council disaster technical committee, beneficiary registration and tracking and monitoring supplies of food and not - food distribution), Regional Council should be encouraged to fill the positions of Regional Disasters Management Coordinators. Some solutions to the flood problem: Floods are a consequence of natural hydro-meteorological phenomenon, combined with their interaction with the catchment characteristics. Through interventions in changing the characteristics of the catchment the run-off processes can be altered, thereby making it possible to reduce the magnitude of the flood hazard thus generated. Urban drainage systems, made up of channels, culverts, sewers etc., are meant to prevent local floods by conveying storm water away from vulnerable sites. Mostly this is done with the aim of draining storm water as fast as possible out of town. This practice may be benign in coastal cities or in agglomerations with no exposed living spaces downstream, but if cities or urban districts upstream of other riverside settlements drain storm water too quickly, this may cause urban floods downstream. Thus the sustainable urban drainage systems aim for adequate, but not too excessive, drainage in order to mitigate local floods, without creating new hazards downstream. Commonly it presents two major concepts of urban storm drainage: direct runoff versus source control. The latter concept suggests a number of so-called “source control measures” which are meant to either retain or reduce storm water runoff in order to prevent the exceedance of the drainage system and to mitigate the generation of flood hazards downstream. The resulting hydrographs illustrate how the reduction and retention of storm water runoff in a source control drainage systems can cut discharge peaks. The reduction of surface runoff in absolute terms can be achieved by a variety of measures that increase infiltration, evaporation and/or transpiration from the catchment areas that contribute to local flooding. The easiest way to do so is to preserve unsealed and greened spaces in the city. Such spaces are of multifunctional purpose, they: Reduce surface runoff by increasing infiltration and evapotranspiration; Retain water through interception; Filter the percolating water; Recharge groundwater resources; Reduce air pollution and improve the urban microclimate; and Can be used for recreational purposes in the form of parks and gardens. Since the availability of space is highly limited in cities, less extensive measures that enable effective in-town infiltration can also be used. Among them are: Infiltration trenches; Soak-aways; and Measures that increase the permeability of larger surfaces.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 256
Northern Regions. Flood Risk Management Plan 2011
Essentially, infiltration trenches and soakaways consist of a trench or a pit filled with a top layer of permeable material like crushed stones or gravel and a bottom layer of sand. Since the potential for in-town infiltration and evapotranspiration is limited, especially in cities where convective precipitation and non-absorptive soils prevail, measures of storm water retention are vital for the mitigation of urban floods as well as for the prevention of downstream floods. Storm water retention can be achieved or facilitated by constructing basins or ponds that temporarily store surface runoff and release it subsequently at a controlled rate. There is a variety of retention basins and ponds - open or covered, wet or dry, online or offline – that may serve various purposes. The advantage of multipurpose dry ponds is the maximization of land use. They can also contribute to infiltration and to the removal of pollutants. There are many creative possibilities to use the same space for everyday activities as well as for occasional flooding. Furthermore, wet ponds in the form of artificial lakes can be of aesthetic value. Temporary storm water retention can be made in sport courts, parking sites, playgrounds etc. In all cases sedimentation has to be considered a likely problem in basins and ponds. These retention basins require flow equalization facilities to prevent flooding of and damage to such facilities. Implementation: The purpose of this plan is to inform and guide all the local stakeholders in the undertaking of its planning responsibilities, and in integrating and coordinating the activities of different agencies that influence the use and development of land that may be affected by natural hazards. The plan will also guide local governments, other agencies and state government of those aspects of state planning policy concerning natural hazard mitigation that should be taken into account in planning decision-making. There are many agencies that have the power to permit development that may be subject to natural hazards. While recognizing these responsibilities, this plan provides a checklist to enable the delivery of a consistent approach to natural hazard mitigation.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 257
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 258
Northern Regions. Flood Risk Management Plan 2011
OHANGWENA REGION FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 259 Northern Regions. Flood Risk Management Plan 2011
6.3.3- OHANGWENA REGION
6.3.3.1- Regional Proposals ! Elaboration of an integral study on the subject of the region’s human settlements system. ! Elaboration of feasibility studies and project designs to improve water drainage in the specific problematic places. ! Revision of urban plans for the gradual relocation of the people living in low-lying flood-prone areas. ! Preparation of the Urban Master Plan for Helao Nafidi regulating the urban development according to environmental issues. ! Revision of the existing urban master plans for Eenhana. ! Preparation of a planning study on the specific subject of the human settlements system (territorial distribution, services provision, interconnection, migration, etc…)
! Gradual relocation of the misplaced buildings and infrastructure to higher ground and in accordance with the urban plans´ provisions.
! To determine the more adequate way to channel the waters through the evacuation culverts taking advantage of the sites` topography. Existing and/or improved culverts must be systematically cleared. ! In some specific points infiltration wells could be of use also channeling the waters towards them. ! Improvement of the natural watercourses by means, for instance, of deepening the existing oshanas ! Re-design the culverts in correspondence with the volumes of water to evacuate and the water and ground levels, plus periodical maintenance works. ! Stop excavations and restore previous conditions of each affected area.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 260
Northern Regions. Flood Risk Management Plan 2011
HELAO NAFIDI TOWN FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 261 Northern Regions. Flood Risk Management Plan 2011
6.3.3.2- Helao Nafidi Proposals Helao Nafidi is located in the middle of several oshanas, being very affected by floods during the rainy season. The town has a unique attribute due to the fact that it is made of several urban and rural areas, with strong differences among them. The four urban zones (Oshikango, Engela – Omafo, Ohangwena and Onhuno) are clearly bordered, isolated within a huge geographical area and no plan is already prepared in order to foresee the future structure of the whole town, generating a scattered and in some cases chaotic development without taking into consideration the special environmental characteristics of the area. At the same time, the town has a high potential for future commercial development, due to its location in the Namibian – Angolan border. The Development Proposals for the town will consider the identification of three major sectors, as well as the flood prone areas: Sector 1. - Existing urban area of the Oshikango suburb. Sector 2. - Existing urban areas of the Engela – Omafo, Ohangwena y Onhuno suburbs. Sector 3. – Vacant lands within town boundaries. Land Use Proposals: Sectors 1, 2: Completion of the vacant land located within the sectors, including infrastructural solutions, specially the storm water drainage systems. Sector 3: Planning and implementation of urban studies integrating all the existing and future development areas, taking into consideration the presence of important flood prone areas that will require special studies. Flood Prone Areas: For the flood prone areas farther regulations will be established, which shall apply to all lands within the existing urban area in the floodways or flood prone areas within the zoning jurisdiction of the town of Helao Nafidi that are subject to a one percent or greater chance of flooding in any given year.
The degree of flood protection required by these regulations is considered reasonable for regulatory purposes and is based on engineering and scientific methods of study. Larger floods may occur on rare occasions or the flood height may be increased by man-made or natural causes, such as ice jams and bridge openings restricted by debris. Compliance with these regulations does not imply that lands outside a floodplain or flood prone areas or uses within such areas will be free from flooding or flood damage.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 262
Northern Regions. Flood Risk Management Plan 2011
6.3.3.2.2- Helao Nafidi. Contingency Plan Helao Nafidi is located in a very flat geographical area. Presence of main natural water courses (oshanas) in surrounding areas (running from north to south in the entire town complex and the suburb). All these elements are affected by flood because of water coming from Cuvelai basin and heavy rainfall. Most of the towns areas are affected, the flood water cover the flood prone areas and main access roads interrupting accessibility to some vital services (hospitals and private clinics, schools, shops, etc) and other human settlements located nearby (Enhana). The lack of proper infrastructure to allow the free flow of the water is the main reason why the Ohangwena suburb is almost totally affected by floods, due its location in a low lying area without a proper storm water drainage system. Similar situation is present in Oshikango suburb, aggravated by uncontrolled urban development, which has blocked natural water ways. In order to mitigate these affectations, some partial solutions have been constructed in some gravel roads without an integrated approach that takes into consideration the whole urban area. Scenario for planning purpose ! Hazard and resulting emergency Helao Nafidi town is affected during the rainy season by floods as consequences of heavy rainwater that inundate principally low lying areas within town boundaries and the overflow of the oshanas that surrounding some parts of the town, due to the high volume of water coming from the Cuvelai basin. The emergency stated is only proclaimed by the central government. ! Likely triggers o) Early warning indicators and triggers: They are not an early warning system. The initial warnings come from the news by TV about heavy rains at neighbor countries and some information from a Central Office of the Ministry of Agriculture and for National Meteorological forecast. The Town Council at this area works hand to hand with Regional Council p) Continuous heavy rains in the town area q) Also from INTERNET about climate and meteorological conditions in the south part of African Continent. Nevertheless, sometimes appears news at national newspaper, like in Namibian of January 18 / 2011: r) Responsible for monitoring the early warning indicators and triggers: The Town Chief Executive Officer (CEO) is the maximum responsible for monitoring the early warnings, although there is a Town Council’s official directly responsible with that assignment (Mr. Peter Ampweya and Mrs. Miriam Shaulma – are focal point). The Civil Defense Committee is activated during emergency conditions. ! Risk analysis k) How likely is this scenario to occur?
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 263
Northern Regions. Flood Risk Management Plan 2011
Despite of the fact that drought is the most common natural hazard to the majority of the country, during every rainy season (November – April) the area where Helao - Nafidi town is located, becomes very vulnerable to flood events in a process that has seen a recurrence during the last three years. The above – normal and/or high inflows in the Cuvelai basin or the combination of both natural phenomenon is a potential threat to the area, which experienced the worst flood disasters during last period as part of the global climate change. l) What will be the consequences should the scenario occur? The flood disasters cause damages and losses to the public and private sectors (public health and education facilities, housing business, infrastructure and others). The most terrible is the loss of human lives due to drowning and attack by wild life animals. The productive sector (agriculture, commerce – trade and markets) is highly affected (lost of crops production, commercial products, etc.). The population living on most vulnerable areas should be relocated to safer areas, requiring emergency humanitarian support (food, clothes, shelter, water and others). Normal life are disrupted, as some persons cannot come back to their normal place of living and cannot continue with their normal business of carrying a living (jobs loss, crops destroyed, or place of work destroyed). At the same time, people don’t have access to basics needs and services. Some roads are affected in the rural areas during floods. As a result of that fact, is possible to obtain the following table: Helao Nafidi. Table of existing vulnerability in the town:
Total Total of Total Kind of Hazard Vulnerability Vulnerability Vulnerability surface of housing population hazards level surface population household settlement High / Ha. # Hab. XXX Middle Ha. % Hab. % # % High 233,3 21,0 4 508,0 19,6 723,5 High 1 110,8 3 710,0 23 000,0 Storm water Middle 194,4 17,5 3 795,0 16,5 593,6 flooding Middle High 477,6 43,0 9 683,0 42,1 1 561,9 High 1 110,8 3 710,0 23 000,0 Drought Middle ------Middle
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 264
Northern Regions. Flood Risk Management Plan 2011
The main consequences should the scenario occur are: - Most of the businesses and commercial buildings are flooded. - Contamination of the superficial and underground water due the overflow of some wells and septic tanks located in some parts of the town and overflow of the oxidation pond, because this is located in the middle of an oshana. - Some roads are interrupting, preventing the access to some areas, especially to the informal settlements. - Lack of accessibility to some basics social services (schools, hospital, clinics, food and other basic services). - Relocation of affected population to the safer places into the town or in other high places. ! Population at risk Most of the population residing in Helao Nafidi town is at risk during a flood event, especially those living near the flood prone areas (informal settlements, and low lying areas). There is not exact idea of the total amount of people at risk, but could be more than 8 000 Hab. (almost the 35% of the town). Specific vulnerable people to be relocated: Disabled persons, old person and children. If you must evacuate in the event of a flood: ! Always follow the instructions of local emergency officials. ! Take your personal emergency grab-and-go kit with you. This kit should have basic essential items such as prescription medications, eye glasses, important papers, flashlight, battery powered radio, clothing, identification and some cash. ! Ensure each family member has waterproof clothing and footwear. ! Shut and lock doors and windows, including barn doors and gates. Shut off water supply, natural gas and power to all buildings, barns, etc. as identified on farm map. ! If you are evacuating your premises, shut off your gas valve at the meter. ! Rendezvous with family and workers at designated safe meeting place or at local Emergency Services Shelter. ! Anticipated duration of emergency conditions The duration of emergency conditions depends on the weather characteristics and conditions (meteorological situation – duration and intensity of rains, volume of flood water, etc.) and on the capacity of resilience of this geographical area.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 265
Northern Regions. Flood Risk Management Plan 2011
! Budget and other resources to face up to the disaster It don’t exist any special government warehouse with food supply for the affected people, but in emergency cases is used some strategic reserves from the Central Government and of some buildings belonging of Regional Council at Enhana and Helao Nafidi. Vulnerable people at the town must be relocated at safes houses and traditional authority buildings and some schools. Also in a relocation camp (an area in the Oshikango suburb). All the people who live in tents need time to rebuild their houses or built the new houses in case of the most affected. They have officially 4 means of transportation for this proposal. Main Objectives: ! Saving lives ! Preserving assets ! Preventing Mass Migration ! Ensuring access to public services for all the people ! Establishing conditions for restoring of self - reliance ! Minimize damage resulting from emergency situation Program Implementation: ! Immediate Response and Evacuations Routes When the disasters appear in this town, many others means of transportation are designated for help the affected people. Some means from certain local business, private tracks and another soften transports are very useful for many critical situations. Tarred roads are used as principal way of transportation because are safer ways. Nevertheless, most of the roads are not tarred (gravel) so they are very affected by floods with problem of accessibility principally in informal settlements. Also all of roads are affected by strong erosion that is able to destroy them. After flooding is developed a campaign in order to avoid some very often diseases like cholera, malaria, dengue, etc. that could became in a very serious epidemic. ! Long term plans In Helao Nafidi, they haven’t any rescue team (just the normal employers of the office of town council), or Red Cross organization and neither firefighter. It also doesn’t have any educative or informational program to prepare and train a lot of people to confront these natural hazards, like flooding. ! Preparedness and Maintenance Actions A Plan will be updated and revised systematically and it is necessary to prepare some simulation exercises to test the plan and also a proper preparation and capacitation in order to avoid big quantities damages.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 266
Northern Regions. Flood Risk Management Plan 2011
! Major existing restrictions: - Inadequate skilled and trained staff in disaster management in Town Council - Lack of Town Contingency Plan - Disaster management considered an add on activity by Town Council - Lack of clear understanding of roles and responsibilities among stakeholders, even among members of the Civil Defense Committee - Lack of clear guidelines on disasters management procedures (early warning system) - Insufficient financial allocation/contingency fund for disaster management - Inadequate warehouse space - Poor public awareness on flood issues. ! Participants and partnerships in contingency planning. Helao Nafidi Town Council, Home Affairs, Business owners, NORED, NAMPOL, NAMWATER, Schools, etc. Early Warning System: ! Strengthen sharing disasters information locally and trans-boundaries ! Engaged traditional leaders in informatics sharing and dissemination in infrastructural development ! Improve channels of communicating the early warning system results to relevant authorities ! Channel information dissemination trough relevant authorities. At regional level however, the Namibian Disaster Management System (NDMS) appointed two senior people to oversee the coordination of the disaster response. The roles of the two senior officers were among others to: ! Provide a link between disaster response operational levels with the NDMS through weekly report to the Secretary to Cabinet (Chairperson of the National Emergency Management Committee) ! Received donations and facilitate timely distribution to the flood affected ! Continuously monitor the flood situation and facilitating the provision of appropriate response ! Coordinating transport and logistic ! Conducting weekly meetings on the flood disaster response with stakeholders ! Providing media briefs on the flood situation ! Developing medium and long term recommendation for effective flood management and rehabilitation
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 267
Northern Regions. Flood Risk Management Plan 2011
And also, ! The Regional Councils should consider disaster management as an integral part of their activities and not an add on activity and responsibilities given to staff that have other key roles to play in the Regional Councils. ! Regional Emergency Management Units need to be continuously proactive and sensitive to the disaster risk management and should strengthen coordination among all the stakeholders before, during and after disasters. ! To facilitate coordination of disaster risk management activities (preparedness and contingency planning, public awareness, secretariat for the regional council disaster technical committee, beneficiary registration and tracking and monitoring supplies of food and not - food distribution), Regional Council should be encouraged to fill the positions of Regional Disasters Management Coordinators. Some solutions to the flood problem: Floods are a consequence of natural hydro-meteorological phenomenon, combined with their interaction with the catchment characteristics. Through interventions in changing the characteristics of the catchment the run-off processes can be altered, thereby making it possible to reduce the magnitude of the flood hazard thus generated. Urban drainage systems, made up of channels, culverts, sewers etc., are meant to prevent local floods by conveying storm water away from vulnerable sites. Mostly this is done with the aim of draining storm water as fast as possible out of town. This practice may be benign in coastal cities or in agglomerations with no exposed living spaces downstream, but if cities or urban districts upstream of other riverside settlements drain storm water too quickly, this may cause urban floods downstream. Thus the sustainable urban drainage systems aim for adequate, but not too excessive, drainage in order to mitigate local floods, without creating new hazards downstream. Commonly it presents two major concepts of urban storm drainage: direct runoff versus source control. The latter concept suggests a number of so-called “source control measures” which are meant to either retain or reduce storm water runoff in order to prevent the exceedance of the drainage system and to mitigate the generation of flood hazards downstream. The resulting hydrographs illustrate how the reduction and retention of storm water runoff in a source control drainage systems can cut discharge peaks. The reduction of surface runoff in absolute terms can be achieved by a variety of measures that increase infiltration, evaporation and/or transpiration from the catchment areas that contribute to local flooding. The easiest way to do so is to preserve unsealed and greened spaces in the city. Such spaces are of multifunctional purpose, they: Reduce surface runoff by increasing infiltration and evapotranspiration; Retain water through interception; Filter the percolating water; Recharge groundwater resources; Reduce air pollution and improve the urban microclimate; and
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 268
Northern Regions. Flood Risk Management Plan 2011
Can be used for recreational purposes in the form of parks and gardens. Since the availability of space is highly limited in cities, less extensive measures that enable effective in-town infiltration can also be used. Among them are: infiltration trenches; soak- aways; and measures that increase the permeability of larger surfaces. Essentially, infiltration trenches and soakaways consist of a trench or a pit filled with a top layer of permeable material like crushed stones or gravel and a bottom layer of sand. Since the potential for in-town infiltration and evapotranspiration is limited, especially in cities where convective precipitation and non-absorptive soils prevail, measures of storm water retention are vital for the mitigation of urban floods as well as for the prevention of downstream floods. Storm water retention can be achieved or facilitated by constructing basins or ponds that temporarily store surface runoff and release it subsequently at a controlled rate. There is a variety of retention basins and ponds - open or covered, wet or dry, online or offline – that may serve various purposes. The advantage of multipurpose dry ponds is the maximization of land use. They can also contribute to infiltration and to the removal of pollutants. There are many creative possibilities to use the same space for everyday activities as well as for occasional flooding. Furthermore, wet ponds in the form of artificial lakes can be of aesthetic value. Temporary storm water retention can be made in sport courts, parking sites, playgrounds etc. In all cases sedimentation has to be considered a likely problem in basins and ponds. These retention basins require flow equalization facilities to prevent flooding of and damage to such facilities. A complementary multipurpose retention strategy is storm water storage as a source of water supply, so-called “rainwater harvesting”. This is particularly useful in semi-arid areas that experience water stress. Considering economic and environmental advantages and its potential for mitigation of urban floods, rainwater harvesting is not only applicable in towns where fresh water resources are scarce but constitutes a reasonable measure in almost all human settlements. Although unfiltered storm water is normally not of drinking water quality, it is amenable for non-potable purposes such as washing, irrigation, toilet flushing etc. Storm water is usually collected on roofs and stored in tanks or in underground cisterns. Implementation: The purpose of this plan is to inform and guide all the local stakeholders in the undertaking of its planning responsibilities, and in integrating and coordinating the activities of different agencies that influence the use and development of land that may be affected by natural hazards. The plan will also guide local governments, other agencies and state government of those aspects of state planning policy concerning natural hazard mitigation that should be taken into account in planning decision-making. There are many agencies that have the power to permit development that may be subject to natural hazards. While recognizing these responsibilities, this plan provides a checklist to enable the delivery of a consistent approach to natural hazard mitigation.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 269
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 270
Northern Regions. Flood Risk Management Plan 2011
OMUSATI REGION FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 271 Northern Regions. Flood Risk Management Plan 2011
6.3.4 - OMUSATI REGION
6.3.4.1 – Regional Proposals The general proposals for the whole Region are:
! To design and construct general or specific drainage solutions for the affected areas (the use of infiltration wells, canals, etc) wherever feasible in order to maintain as much of the existing facilities as possible.
! Stop further construction on the affected low-lying areas even once the drainage problem is solved.
! To relocate both houses and service facilities from the oshana to safer areas according to the urban development plans.
! To strength control measures on informal constructions on low-lying areas.
! To increase the capacity of road’s culverts in correspondence with the volume of water flows as well as to provide them with periodical maintenance.
! Create or improve drainage gutters along the roads and improve the erosion control by using proper vegetation
! To study probable solutions for the profitable use of the flood waters in agriculture.
! To implement educative campaigns tending to people’s awareness on health problems related to flood situation.
! To obtain the needed topographical information that will allow more accurate analysis.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 272
Northern Regions. Flood Risk Management Plan 2011
OUTAPI TOWN FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 273 Northern Regions. Flood Risk Management Plan 2011
6.3.4.2 – Outapi Town Proposals The Development Proposals for the town of Outapi are prepared considering avoiding the flood risk where possible, substituting less vulnerable uses where avoidance is not possible, and mitigating and managing the risk where avoidance and substitution are not possible. The Plan includes the following aspects: 1. Preparedness, maintenance and flood mitigation actions in the identified areas at risk, 2. Land use projections 3. Functional structure for undeveloped land within town boundaries, 4. General planning proposals and 5. Regulations for future development, 6. Infrastructure solutions (roads, water supply, sewerage, drainage).
Objective: To create a tool for the local authorities to deal with the flood problem and, simultaneously, organize, build and maintain those towns and settlement areas as modern and comfortable places to live and work. The Development Proposals will allow the implementation of solutions to aspects such as flooding, relocating people, water and power supply, sewerage and waste water treatment in each of the selected human settlements. The main recommendations are: ! To stop further constructions (buildings and infrastructure) along the Mwanyangapo Ambunda street, north side of which is a clearly flood-prone area ! Creation of proper drainage solutions on Onhimbu area (extension 2) where there are 37 houses under water ! To stop further constructions in Oshana Onhimbu area (Federation houses) where 43 houses are to be relocated. ! To stop further constructions (buildings and infrastructure) in the Okakwa area (north side of the Ruacana-Oshikuku road) where there are about 12 houses and disabled people workshops. A proper drainage solution should be designed in order to preserve the existing buildings. ! To stop further constructions (buildings and infrastructure) in the Okakwa area (south side of the Ruacana-Oshikuku road) where there are about 20 houses cut off by stranded waters. A proper drainage solution should be designed in order to preserve the existing buildings. Main proposals:
! Kasikili west: Trade Fair area (17.15 hectares). ! Formalization of informal settlements:
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 274
Northern Regions. Flood Risk Management Plan 2011
- Onhimbu West. - Oukwa - Wananyanga - Opa Okakwa (East of Kasikili) ! Bridges in the Tsandi road need to be widened. ! Construction of Prison Headquarters and Correctional Services (offices, sports fields, accommodation, garden area, penitentiary). Traditional houses located in the area need to be relocated and compensated. ! All the streets should be designed with sidewalks. ! Bus and taxi terminal: There is a land allocated in the Ruacana – Oshakati road. ! Designing of main accesses to town. Main land uses: South West (outside existing township boundaries): Urban agricultural/ Sports facilities/ Public open space (flood prone area). In the area there are traditional houses with mahangu fields that need to be compensated. South East (inside existing township boundaries): Higher Education, Heavy Industry, Light Industry, Residential (high income), General Residential. North of Tobias Hainyeko & Onhimbu: 2 Primary Schools, Business. The agriculture district: The southwestern part of the town will have a special zone for agricultural activities. This area will benefit from the controlled water environment and will increase the diversity and succession of nourishment. Flood Prone Areas: For the flood prone areas farther regulations will be established, which shall apply to all lands within the existing urban area in the floodways or flood prone areas within the zoning jurisdiction of the town of Outapi that are subject to a one percent or greater chance of flooding in any given year.
The degree of flood protection required by these regulations is considered reasonable for regulatory purposes and is based on engineering and scientific methods of study.
Larger floods may occur on rare occasions or the flood height may be increased by man- made or natural causes, such as ice jams and bridge openings restricted by debris.
Compliance with these regulations does not imply that lands outside a floodplain or flood prone areas or uses within such areas will be free from flooding or flood damage.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 275
Northern Regions. Flood Risk Management Plan 2011
6.3.4.2.2- Outapi Town. Contingency Plan Outapi Town is located in a very flat geographical area. Presence of main natural water courses (oshanas) in surrounding areas (running from north to south in the west part of the town) a water canal (Ruacana – Oshakati) that border the town on the south and some low lying areas within town borders.
All these elements are affected by flood because of water coming from Cuvelai basin and heavy rainfall. Most of the town areas are affected, the flood water cover the flood prone areas and main access roads interrupting accessibility to some vital services (hospitals, schools, shops, etc) and other human settlements located nearby (Okahao, Oshikuku, Ruacana, Tsandi).
Scenario for planning purpose ! Hazard and resulting emergency Outapi town is affected during the rainy season by floods as consequences of heavy rainwater that inundate low lying areas within town boundaries and the overflow of the Ruacana – Oshakati canal that surrounding the south part of the town, due to the high volume of water coming from the Cuvelai basin. The emergency stated is only proclaimed by the central government. ! Likely triggers s) Early warning indicators and triggers: They are not an early warning system. The initial warnings come from the news by TV about heavy rains at neighbor countries and some information from a Central Office of the Ministry of Agriculture and for National Meteorological forecast t) Continuous heavy rains in the area u) Also from INTERNET about climate and meteorological conditions in the south part of African Continent. Nevertheless, sometimes appears news at national newspaper, like in Namibian of January 18 / 2011: v) Responsible for monitoring the early warning indicators and triggers: It is a share responsibility by the Head of Civil Defense of Outapi Town Council (Focal Point) Mr. Ausiku A.P., the councilors of affected constituencies and the Civil Defense Committee made up by stakeholders from different institutions and organizations. ! Risk analysis m) How likely is this scenario to occur? Despite of the fact that drought is the most common natural hazard to the majority of the country, during every rainy season (November – April) the area where Outapi town is located, becomes very vulnerable to flood events in a process that has seen a recurrence during the last three years. The above – normal and/or high inflows in the Cuvelai basin or the combination of both natural phenomenon is a potential threat to the area, which experienced the worst flood disasters during last period as part of the global climate change.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 276
Northern Regions. Flood Risk Management Plan 2011
n) What will be the consequences should the scenario occur? The flood disasters cause damages and losses to the public and private sectors (public health and education facilities, housing business, infrastructure and others). The most terrible is the loss of human lives due to drowning and attack by wild life and crocodiles. The productive sector (agriculture, commerce – trade and markets) is highly affected (lost of crops production, commercial products, etc.). The population living on most vulnerable areas should be relocated to safer areas, requiring emergency humanitarian support (food, clothes, shelter, water and others). Normal life are disrupted, as some persons cannot come back to their normal place of living and cannot continue with their normal business of carrying a living (jobs loss, crops destroyed, or place of work destroyed). At the same time, people don’t have access to basics needs and services. As a result of that fact, is possible to obtain the following table:
OUTAPI. Table of existing vulnerability in the town:
Total Total of Total Kind of Hazard Vulnerability Vulnerability Vulnerability surface of housing population hazards level surface population household settlement High / Ha. # Hab. XXX Middle Ha. % Hab. % # % High 42,5 8,3 655 8,1 104 High 512 1237 8089 Storm water Middle 143,4 28,2 2022 25,0 369.8 flooding Middle High 409,6 80 6632 82 977,2 High 512 1237 8089 Drought Middle ------Middle
The main consequences should the scenario occur are: - Most of the businesses and commercial buildings located in the town are flooded, including the lodges. - Contamination of the superficial and underground water due the overflow of some wells and septic tanks located in some parts of the town and overflow of the oxidation ponds. - Some roads are interrupting, preventing the access to some areas, especially to
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 277
Northern Regions. Flood Risk Management Plan 2011
the informal settlements. - Lack of accessibility to some basics social services (schools, clinics, food and other basic services). - Relocation of affected population to the safer places into the town. ! Population at risk Most of the population residing in Outapi town is at risk during a flood event, especially those living near the flood prone areas (informal settlements, and low lying areas). There is not exact idea of the total amount of people at risk, but could be more than 2 500 Hab. (the 33% of the town). Some details about the population that should be relocated during flood events are the following: ! South area (south of the canal and west of Outapi, Tsandi, Okahao road) – 2 houses and 23 persons. Specific vulnerable people: Disabled persons, children. ! North area (Onhimbu area, north of Oshakati - Ruacana road, natural water course) – 20 shacks and about 80 people. Specific vulnerable people: old persons, children.
If you must evacuate in the event of a flood: ! Always follow the instructions of local emergency officials. ! Take your personal emergency grab-and-go kit with you. This kit should have basic essential items such as prescription medications, eye glasses, important papers, flashlight, battery powered radio, clothing, identification and some cash. ! Ensure each family member has waterproof clothing and footwear. ! Shut and lock doors and windows, including barn doors and gates. Shut off water supply, natural gas and power to all buildings, barns, etc. as identified on farm map. ! If you are evacuating your premises, shut off your gas valve at the meter. ! Rendezvous with family and workers at designated safe meeting place or at local Emergency Services Shelter. ! Anticipated duration of emergency conditions The duration of emergency conditions depends on the weather characteristics and conditions (meteorological situation – duration and intensity of rains, volume of flood water, etc.) and on the capacity of resilience of this geographical area. ! Budget and other resources to face up to the disaster It don’t exist any special government warehouse with food supply for the affected people, but in emergency cases is used some strategic reserves from the Central Government and of two buildings belonging of Regional Council.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 278
Northern Regions. Flood Risk Management Plan 2011
The budget for the town in case of some kind of disaster is about $10,000 NAD. This budget should include capacity building, training and some additional information for the people in town. Vulnerable people at the town must be relocated at safes installations and houses: traditional authority buildings and schools. All the people who live in tents need time to rebuild their houses. They have officially 3 means of transportation.
Main Objectives: ! Saving lives ! Preserving assets ! Preventing Mass Migration ! Ensuring access to public services for all the people ! Establishing conditions for restoring of self - reliance ! Minimize damage resulting from emergency situation Program Implementation: ! Immediate Response and Evacuations Routes When the disasters appear in this town, many others means of transportation are designated for help the affected people. Some means from certain local business, private tracks and another soften transports are very useful for many critical situations. The district hospital is located at a safer land, for special attention to the town’s people affected during the disaster and emergency situation. Tarred roads are used as principal way of transportation because are safer ways. Nevertheless, most of the roads are not tarred (gravel) so they are very affected by floods with problem of accessibility principally in informal settlements. Also all of roads are affected by strong erosion that is able to destroy them. After flooding is developed a campaign in order to avoid some very often diseases like cholera, malaria, dengue, etc. that could became in a very serious epidemics. ! Long term plans In Outapi, they haven’t any rescue team (just the normal employers of the office of town council), or Red Cross organization and neither firefighter. It also doesn’t have any educative or informational program to prepare and train a lot of people to confront these natural hazards, like flooding. ! Preparedness and Maintenance Actions A Plan will be updated and revised systematically and it is necessary to prepare some simulation exercises to test the plan and also a proper preparation and capacitation in order to avoid big quantities damages.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 279
Northern Regions. Flood Risk Management Plan 2011
! Major existing restrictions: - Inadequate skilled and trained staff in disaster management in Town Council - Lack of Town Contingency Plan - Disaster management considered an add on activity by Town Council - Lack of clear understanding of roles and responsibilities among stakeholders, even among members of the Civil Defense Committee - Lack of clear guidelines on disasters management procedures (early warning system) - Insufficient financial allocation/contingency fund for disaster management - Inadequate warehouse space - Poor public awareness on flood issues. ! Participants and partnerships in contingency planning. Outapi Town Council, Home Affairs, Business owners, NORED, NAMPOL, NAMWATER, Schools, etc.
Early Warning System: ! Strengthen sharing disasters information locally and trans-boundaries ! Engaged traditional leaders in informatics sharing and dissemination in infrastructural development ! Improve channels of communicating the early warning system results to relevant authorities ! Channel information dissemination trough relevant authorities. At regional level however, the Namibian Disaster Management System (NDMS) appointed two senior people to oversee the coordination of the disaster response. The roles of the two senior officers were among others to: ! Provide a link between disaster response operational levels with the NDMS through weekly report to the Secretary to Cabinet (Chairperson of the National Emergency Management Committee) ! Received donations and facilitate timely distribution to the flood affected ! Continuously monitor the flood situation and facilitating the provision of appropriate response ! Coordinating transport and logistic ! Conducting weekly meetings on the flood disaster response with stakeholders ! Providing media briefs on the flood situation
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 280
Northern Regions. Flood Risk Management Plan 2011
! Developing medium and long term recommendation for effective flood management and rehabilitation And also, ! The Regional Councils should consider disaster management as an integral part of their activities and not an add on activity and responsibilities given to staff that have other key roles to play in the Regional Councils. ! Regional Emergency Management Units need to be continuously proactive and sensitive to the disaster risk management and should strengthen coordination among all the stakeholders before, during and after disasters. ! To facilitate coordination of disaster risk management activities (preparedness and contingency planning, public awareness, secretariat for the regional council disaster technical committee, beneficiary registration and tracking and monitoring supplies of food and not - food distribution), Regional Council should be encouraged to fill the positions of Regional Disasters Management Coordinators. Some solutions to the flood problem: Floods are a consequence of natural hydro-meteorological phenomenon, combined with their interaction with the catchment characteristics. Through interventions in changing the characteristics of the catchment the run-off processes can be altered, thereby making it possible to reduce the magnitude of the flood hazard thus generated. Urban drainage systems, made up of channels, culverts, sewers etc., are meant to prevent local floods by conveying storm water away from vulnerable sites. Mostly this is done with the aim of draining storm water as fast as possible out of town. This practice may be benign in coastal cities or in agglomerations with no exposed living spaces downstream, but if cities or urban districts upstream of other riverside settlements drain storm water too quickly, this may cause urban floods downstream. Thus the sustainable urban drainage systems aim for adequate, but not too excessive, drainage in order to mitigate local floods, without creating new hazards downstream. Commonly it presents two major concepts of urban storm drainage: direct runoff versus source control. The latter concept suggests a number of so-called “source control measures” which are meant to either retain or reduce storm water runoff in order to prevent the exceedance of the drainage system and to mitigate the generation of flood hazards downstream. The resulting hydrographs illustrate how the reduction and retention of storm water runoff in a source control drainage systems can cut discharge peaks. The reduction of surface runoff in absolute terms can be achieved by a variety of measures that increase infiltration, evaporation and/or transpiration from the catchment areas that contribute to local flooding. The easiest way to do so is to preserve unsealed and greened spaces in the city. Such spaces are of multifunctional purpose, they: Reduce surface runoff by increasing infiltration and evapotranspiration; Retain water through interception; Filter the percolating water;
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 281
Northern Regions. Flood Risk Management Plan 2011
Recharge groundwater resources; Reduce air pollution and improve the urban microclimate; and Can be used for recreational purposes in the form of parks and gardens. Since the availability of space is highly limited in cities, less extensive measures that enable effective in-town infiltration can also be used. Among them are: infiltration trenches; soak- aways; and measures that increase the permeability of larger surfaces. Essentially, infiltration trenches and soakaways consist of a trench or a pit filled with a top layer of permeable material like crushed stones or gravel and a bottom layer of sand. Since the potential for in-town infiltration and evapotranspiration is limited, especially in cities where convective precipitation and non-absorptive soils prevail, measures of storm water retention are vital for the mitigation of urban floods as well as for the prevention of downstream floods. Storm water retention can be achieved or facilitated by constructing basins or ponds that temporarily store surface runoff and release it subsequently at a controlled rate. There is a variety of retention basins and ponds - open or covered, wet or dry, online or offline – that may serve various purposes. The advantage of multipurpose dry ponds is the maximization of land use. They can also contribute to infiltration and to the removal of pollutants. There are many creative possibilities to use the same space for everyday activities as well as for occasional flooding. Furthermore, wet ponds in the form of artificial lakes can be of aesthetic value. Temporary storm water retention can be made in sport courts, parking sites, playgrounds etc. In all cases sedimentation has to be considered a likely problem in basins and ponds. These retention basins require flow equalization facilities to prevent flooding of and damage to such facilities. A complementary multipurpose retention strategy is storm water storage as a source of water supply, so-called “rainwater harvesting”. This is particularly useful in semi-arid areas that experience water stress. Considering economic and environmental advantages and its potential for mitigation of urban floods, rainwater harvesting is not only applicable in towns where fresh water resources are scarce but constitutes a reasonable measure in almost all human settlements. Although unfiltered storm water is normally not of drinking water quality, it is amenable for non-potable purposes such as washing, irrigation, toilet flushing etc. Storm water is usually collected on roofs and stored in tanks or in underground cisterns. Implementation: The purpose of this plan is to inform and guide all the local stakeholders in the undertaking of its planning responsibilities, and in integrating and coordinating the activities of different agencies that influence the use and development of land that may be affected by natural hazards. The plan will also guide local governments, other agencies and state government of those aspects of state planning policy concerning natural hazard mitigation that should be taken into account in planning decision-making. There are many agencies that have the power to permit development that may be subject to natural hazards. While recognizing these responsibilities, this plan provides a checklist to enable the delivery of a consistent approach to natural hazard mitigation.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 282
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 283
Northern Regions. Flood Risk Management Plan 2011
OKALONGO SETTLEMENT FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 284 Northern Regions. Flood Risk Management Plan 2011
6.3.4.3- Okalongo Settlement Proposals Although at the present time Okalongo is categorized as a settlement area, this Plan foresees an intense future development and an eventual proclamation as a town, considering the important location of the area in the north part of the Omusati Region, with a high attraction for the rural population in search of social services (hospital, education) and the closeness to the Angolan border (about 6 km)
The new districts: The town will grow mostly to the south and north east, where the high lands are located, in different districts. The new districts are organised around streets and public squares and composed of residential buildings, commercial facilities, basic services, offices, as well as nurseries, socio-cultural centres, clubs, police stations, etc.
The business and commercial areas: The business and commercial development will follow the trend to be localized along the main roads of the urban area, especially at the intersection of the Oshikuku – Okahao and Anamulenge – Engela roads, generating the main town center area, where the most important commercial and business facilities will be located.
The axes: The plan of the extension creates two main avenues with the incorporation to the urban design of the existing main roads: the Anamulenge – Engela road and the Oshikuku – Okalongo road, with the extension of this last one further north considering a possible continuation to the Angolan border in the future. Both main avenues will be emphasized by the location of higher buildings (3 – 4 stories), squares and elements of urban furniture.
The suburban park: The main natural river in the town, located on the western side, will be deepened to facilitate the water flow during the rainy season, considering the construction of a 4.5 km dike to avoid that neighboring areas to be affected during flood events. The whole area will be preserved as a natural park, with a predominance of green areas
The industrial districts: Industry and enterprises will be located to the south, close to the town border, adjacent to the road to Oshikuku. This well-considered location provides an ideal link with the main road existing in the north part of the country (Oshakati – Ruacana).
This optimal combination of industry, small & medium enterprises and efficient transportation infrastructure will create and attract new economic activities and will provide extra jobs.
Public facilities and installations: The location of facilities and installations necessary for a town of 10.000 inhabitants such as schools, nurseries, social centres, post offices, theatres, cinemas, will be a subject of further consultations with local authorities. The possibility of erecting these facilities is secured by the land reserves situated in suitable places of various quarters. Public facilities of monumental character shall constitute vistas, situated at squares or in public parks. Technical installations (purification plants, electrical substations, bus and tram depots etc.) will be situated in the suburban areas, in the vicinity of main roads of peripheral circulation
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 285
Northern Regions. Flood Risk Management Plan 2011
6.3.4.3.2- Okalongo Town. Contingency Plan Okalongo Settlement is located among several oshanas, which are flood prone areas, affecting parts of the land due to their overflows. There are some low-laying areas within settlement boundaries that are affected by heavy rainwater, aggravated by the lack of a proper water drainage system, provoking that the rainwater stands still; affecting houses and other properties and buildings. Scenario for planning purpose ! Hazard and resulting emergency Okalongo Settlement is affected during the rainy season by floods as consequences of heavy rainwater that inundate low lying areas within town boundaries and the overflow of the oshanas surrounding the town, due to the high volume of water coming from the Cuvelai basin. During a flood event in the area, the resulting emergency is a general affectation of the whole area especially to the buildings (houses, services and business) located in the flood prone areas (oshanas), the Engela – Anamulenge gravel road is out off and the accessibility to the main social services (hospital, schools and commercial stores) are seriously compromised and damaged. ! Likely triggers w) Early warning indicators and triggers: They are not an early warning system. The initial warnings come from the news by TV about heavy rains at neighbor countries and some information from a Central Office of the Ministry of Agriculture and for National Meteorological forecast through the Regional Council. x) Continuous heavy rains in the area y) Also from INTERNET about climate and meteorological conditions in the south part of African Continent. Nevertheless, sometimes appears news at national newspaper, like in Namibian of January 18 / 2011: z) Responsible for monitoring the early warning indicators and triggers: The responsibility is shared by the Regional Council and the councilors. The Civil Defense Committee is not active only in emergency situations is conformed an Emergency Committee made up by different community actors (local authorities, stakeholders, traditional leaders, health professionals). ! Risk analysis o) How likely is this scenario to occur? Despite of the fact that drought is the most common natural hazard to the majority of the country, during every rainy season (November – April) the area where Okalongo Settlement is located, becomes very vulnerable to flood events in a process that has seen a recurrence during the last three years.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 286
Northern Regions. Flood Risk Management Plan 2011
The above – normal and/or high inflows in the Cuvelai basin or the combination of both natural phenomenon is a potential threat to the area, which experienced the worst flood disasters during last period as part of the global climate change. p) What will be the consequences should the scenario occur? The flood disasters cause damages and losses to the public and private sectors (public health and education facilities, housing business, infrastructure and others). The most terrible is the loss of human lives due to drowning and attack by wild life animals. The productive sector (agriculture, commerce – trade and markets) is highly affected (lost of crops production, commercial products, etc.). The population living on most vulnerable areas should be relocated to safer areas, requiring emergency humanitarian support (food, clothes, shelter, water and others). Normal life are disrupted, as some persons cannot come back to their normal place of living and cannot continue with their normal business of carrying a living (jobs loss, crops destroyed, or place of work destroyed). At the same time, people don’t have access to basics needs and services. As a result of that fact, is possible to obtain the following table: OKALONGO SETTLEMENT. Table of existing vulnerability:
Total Total of Total Kind of Hazard Vulnerability Vulnerability Vulnerability surface of housing population hazards level surface population household settlement High / Ha. % Hab. % # % Ha. # Hab. XXX Middle 31,8 15,0 87,92 11,2 18,2 9,5 High 212 192 785 Storm water 65,7 31,0 251 32,0 54,9 28,6 flooding Middle 132,3 62,4 447,4 57,0 116,2 60,5 High 212 192 785 Drought ------Middle
The main consequences should the scenario occur are: - Some services and social installations are flooding. - Contamination of the superficial due the overflow of some wells and septic tanks located in some parts of the town and overflow of the oxidation ponds. - Some roads are interrupting, preventing the access to some areas, especially to the more informal houses. - Lack of accessibility to some basics social services (schools, clinics, food and other basic services). - Relocation of affected population to the safer places into the settlement.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 287
Northern Regions. Flood Risk Management Plan 2011
Population at risk Most of the population residing in Okalongo Settlement is at risk during a flood event, especially those living near the flood prone areas (oshanas, north side of the Anamulenge – Engela gravel road) where a high number of houses, business and some services are located. There are not exact figures of the amount of people at risk, but it is around 300 people. If you must evacuate in the event of a flood: ! Always follow the instructions of local emergency officials. ! Take your personal emergency grab-and-go kit with you. This kit should have basic essential items such as prescription medications, eye glasses, important papers, flashlight, battery powered radio, clothing, identification and some cash. ! Ensure each family member has waterproof clothing and footwear. ! Shut and lock doors and windows, including barn doors and gates. Shut off water supply, natural gas and power to all buildings, barns, etc. as identified on farm map. ! If you are evacuating your premises, shut off your gas valve at the meter. ! Rendezvous with family and workers at designated safe meeting place or at local Emergency Services Shelter. Anticipated duration of emergency conditions The duration of emergency conditions depends on the weather characteristics and conditions (meteorological situation – duration and intensity of rains, volume of flood water, etc.) and on the capacity of resilience of this geographical area. Budget and other resources to face up to the disaster It don’t exist any special government warehouse with food supply for the affected people, but in emergency cases is used some strategic reserves from the Central Government and of some buildings belonging of Regional Council. Vulnerable people at the town must be relocated at safes houses: traditional authority buildings and schools. All the people who live in tents need time to rebuild their houses. Main Objectives: ! Saving lives ! Preserving assets ! Preventing Mass Migration ! Ensuring access to public services for all the people ! Establishing conditions for restoring of self - reliance ! Minimize damage resulting from emergency situation
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 288
Northern Regions. Flood Risk Management Plan 2011
Program Implementation: ! Immediate Response and Evacuations Routes When the disasters appear in this town, many others means of transportation are designated for help the affected people. Some means from certain local business, private tracks and another soften transports are very useful for many critical situations. The hospital is located at a safer land, for special attention to the town’s people affected during the disaster and emergency situation. Tarred roads are used as principal way of transportation because are safer ways. Nevertheless, most of the roads are not tarred (gravel) so they are very affected by floods with problem of accessibility principally in informal settlements. Also all of roads are affected by strong erosion that is able to destroy them. After flooding is developed a campaign in order to avoid some very often diseases like cholera, malaria, dengue, etc. that could became in a very serious epidemics. ! Long term plans In Okalongo, they haven’t any rescue team (just the normal employers of the office of constituency), or Red Cross organization and neither firefighter. It also doesn’t have any educative or informational program to prepare and train a lot of people to confront these natural hazards, like flooding. ! Preparedness and Maintenance Actions A Plan will be updated and revised systematically and it is necessary to prepare some simulation exercises to test the plan and also a proper preparation and capacitation in order to avoid big quantities damages. ! Major existing restrictions: - Inadequate skilled and trained staff in disaster management in Town Council - Lack of Town Contingency Plan - Disaster management considered an add on activity by Town Council - Lack of clear understanding of roles and responsibilities among stakeholders, even among members of the Civil Defense Committee - Lack of clear guidelines on disasters management procedures (early warning system) - Insufficient financial allocation/contingency fund for disaster management - Inadequate warehouse space - Poor public awareness on flood issues. ! Participants and partnerships in contingency planning. Early Warning System: ! Strengthen sharing disasters information locally and trans-boundaries
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 289
Northern Regions. Flood Risk Management Plan 2011
! Engaged traditional leaders in informatics sharing and dissemination in infrastructural development ! Improve channels of communicating the early warning system results to relevant authorities ! Channel information dissemination trough relevant authorities. At regional level however, the Namibian Disaster Management System (NDMS) appointed two senior people to oversee the coordination of the disaster response. The roles of the two senior officers were among others to: ! Provide a link between disaster response operational levels with the NDMS through weekly report to the Secretary to Cabinet (Chairperson of the National Emergency Management Committee) ! Received donations and facilitate timely distribution to the flood affected ! Continuously monitor the flood situation and facilitating the provision of appropriate response ! Coordinating transport and logistic ! Conducting weekly meetings on the flood disaster response with stakeholders ! Providing media briefs on the flood situation ! Developing medium and long term recommendation for effective flood management and rehabilitation And also, ! The Regional Councils should consider disaster management as an integral part of their activities and not an extra activity and responsibilities given to staff that have other key roles to play in the Regional Councils. ! Regional Emergency Management Units need to be continuously proactive and sensitive to the disaster risk management and should strengthen coordination among all the stakeholders before, during and after disasters. ! To facilitate coordination of disaster risk management activities (preparedness and contingency planning, public awareness, secretariat for the regional council disaster technical committee, beneficiary registration and tracking and monitoring supplies of food and not - food distribution), Regional Council should be encouraged to fill the positions of Regional Disasters Management Coordinators. Some solutions to the flood problem: Floods are a consequence of natural hydro-meteorological phenomenon, combined with their interaction with the catchment characteristics. Through interventions in changing the characteristics of the catchment the run-off processes can be altered, thereby making it possible to reduce the magnitude of the flood hazard thus generated. Urban drainage systems, made up of channels, culverts, sewers etc., are meant to prevent local floods by conveying storm water away from vulnerable sites. Mostly this is done with the aim of
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 290
Northern Regions. Flood Risk Management Plan 2011 draining storm water as fast as possible out of town. This practice may be benign in coastal cities or in agglomerations with no exposed living spaces downstream, but if cities or urban districts upstream of other riverside settlements drain storm water too quickly, this may cause urban floods downstream. Commonly it presents two major concepts of urban storm drainage: direct runoff versus source control. The latter concept suggests a number of so-called “source control measures” which are meant to either retain or reduce storm water runoff in order to prevent the exceedance of the drainage system and to mitigate the generation of flood hazards downstream. The resulting hydrographs illustrate how the reduction and retention of storm water runoff in a source control drainage systems can cut discharge peaks. The reduction of surface runoff in absolute terms can be achieved by a variety of measures that increase infiltration, evaporation and/or transpiration from the catchment areas that contribute to local flooding. The easiest way to do so is to preserve unsealed and greened spaces in the city. Such spaces are of multifunctional purpose, they reduce surface runoff by increasing infiltration and evapotranspiration; retain water through interception; filter the percolating water; recharge groundwater resources; reduce air pollution and improve the urban microclimate; and can be used for recreational purposes in the form of parks and gardens. Since the availability of space is highly limited in cities, less extensive measures that enable effective in-town infiltration can also be used. Among them are infiltration trenches; soak- aways; and measures that increase the permeability of larger surfaces. Essentially, infiltration trenches and soakaways consist of a trench or a pit filled with a top layer of permeable material like crushed stones or gravel and a bottom layer of sand. Since the potential for in-town infiltration and evapotranspiration is limited, especially in cities where convective precipitation and non-absorptive soils prevail, measures of storm water retention are vital for the mitigation of urban floods as well as for the prevention of downstream floods. Storm water retention can be achieved or facilitated by constructing basins or ponds that temporarily store surface runoff and release it subsequently at a controlled rate. There is a variety of retention basins and ponds - open or covered, wet or dry, online or offline – that may serve various purposes. The advantage of multipurpose dry ponds is the maximization of land use. They can also contribute to infiltration and to the removal of pollutants. There are many creative possibilities to use the same space for everyday activities as well as for occasional flooding. Furthermore, wet ponds in the form of artificial lakes can be of aesthetic value. Temporary storm water retention can be made in sport courts, parking sites, playgrounds etc. In all cases sedimentation has to be considered a likely problem in basins and ponds. These retention basins require flow equalization facilities to prevent flooding of and damage to such facilities. Considering economic and environmental advantages and its potential for mitigation of urban floods, rainwater harvesting is not only applicable in towns where fresh water resources are scarce but constitutes a reasonable measure in almost all human settlements. Although unfiltered storm water is normally not of drinking water quality, it is amenable for non-potable purposes such as washing, irrigation, toilet flushing etc. Storm water is usually collected on roofs and stored in tanks or in underground cisterns.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 291
Northern Regions. Flood Risk Management Plan 2011
Implementation: The purpose of this plan is to inform and guide all the local stakeholders in the undertaking of its planning responsibilities, and in integrating and coordinating the activities of different agencies that influence the use and development of land that may be affected by natural hazards. The plan will also guide local governments, other agencies and state government of those aspects of state planning policy concerning natural hazard mitigation that should be taken into account in planning decision-making. There are many agencies that have the power to permit development that may be subject to natural hazards. While recognizing these responsibilities, this plan provides a checklist to enable the delivery of a consistent approach to natural hazard mitigation.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 292
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 293
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 294
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 295
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 296
Northern Regions. Flood Risk Management Plan 2011
OSHIKUKU TOWN FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 297 Northern Regions. Flood Risk Management Plan 2011
6.3.4.4- Oshikuku Town Proposals The town area is partially affected by flood events. It is located between two shallow oshanas, which are flood prone areas, affecting parts of the town during rainy season. The Ruacana-Oshakati water canal, located within town boundary, affects adjacent areas when overflow. There are several low-lying areas within town boundaries, affected by heavy rainwater, aggravated by the lack of a proper storm water drainage system. The Development Proposals for the town will consider the identification of three major sectors, as well as the flood prone areas: Sector 1. - Existing urban area. Sector 2. - Northern area. Sector 3. - Southern area. The plan considers also the construction of a highway on the southern part to divert the heavy traffic outside the town area. Land Use Proposals: Sector 1: Completion of the vacant land located within the sector, including infrastructural solutions, specially the storm water drainage system. Sector 2: Completion of the vacant land located within the sector, including infrastructural solutions, specially the storm water drainage system. Sector 3: Planning of the future development areas of the town, including infrastructural solutions, specially the storm water drainage system. Flood Prone Areas: For the flood prone areas farther regulations will be established, which shall apply to all lands within the existing urban area in the floodways or flood prone areas within the zoning jurisdiction of the town of Oshikuku that are subject to a one percent or greater chance of flooding in any given year.
The degree of flood protection required by these regulations is considered reasonable for regulatory purposes and is based on engineering and scientific methods of study. Larger floods may occur on rare occasions or the flood height may be increased by man-made or natural causes, such as ice jams and bridge openings restricted by debris.
Compliance with these regulations does not imply that lands outside a floodplain or flood prone areas or uses within such areas will be free from flooding or flood damage.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 298
Northern Regions. Flood Risk Management Plan 2011
6.3.4.4.2- Oshikuku Town. Contingency Plan Oshikuku town is located between two oshanas, which are flood prone areas, affecting parts of the town due to their overflows. At the same time, the Ruacana - Oshakati water-canal presence within town boundary is another hazard, affecting neighboring areas when it overflows. There are some low-laying areas within town boundaries that are affected by heavy rainwater, aggravated by the lack of a proper water drainage system, provoking that the rainwater stands still; affecting houses and other properties. Scenario for planning purpose ! Hazard and resulting emergency Oshikuku town is affected during the rainy season by floods as consequences of heavy rainwater that inundate low lying areas within town boundaries and the overflow of the two oshanas surrounding the town, due to the high volume of water coming from the Cuvelai basin. At the same time, the Ruacana – Oshakati water canal that runs within and out urban areas affecting neighboring areas. ! Likely triggers aa) Early warning indicators and triggers: They are not an early warning system. The initial warnings come from the news by TV about heavy rains at neighbor countries and some information from a Central Office of the Ministry of Agriculture and for National Meteorological forecast bb) Continuous heavy rains in the area cc) Also from INTERNET about climate and meteorological conditions in the south part of African Continent. Nevertheless, sometimes appears news at national newspaper, like in Namibian of January 18 / 2011: dd) Responsible for monitoring the early warning indicators and triggers: There is no appointed person among the Town Council staff responsible for these tasks. The Civil Defense Committee is not active. ! Risk analysis q) How likely is this scenario to occur? Despite of the fact that drought is the most common natural hazard to the majority of the country, during every rainy season (November – April) the area where Oshikuku town is located, becomes very vulnerable to flood events in a process that has seen a recurrence during the last three years. The above – normal and/or high inflows in the Cuvelai basin or the combination of both natural phenomenon is a potential threat to the area, which experienced the worst flood disasters during last period as part of the global climate change.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 299
Northern Regions. Flood Risk Management Plan 2011
r) What will be the consequences should the scenario occur? The flood disasters cause damages and losses to the public and private sectors (public health and education facilities, housing business, infrastructure and others). The most terrible is the loss of human lives due to drowning and attack by wild life and crocodiles. The productive sector (agriculture, commerce – trade and markets) is highly affected (lost of crops production, commercial products, etc.). The population living on most vulnerable areas should be relocated to safer areas, requiring emergency humanitarian support (food, clothes, shelter, water and others). Normal life are disrupted, as some persons cannot come back to their normal place of living and cannot continue with their normal business of carrying a living (jobs loss, crops destroyed, or place of work destroyed). At the same time, people don’t have access to basics needs and services. As a result of that fact, is possible to obtain the following table: OSHIKUKU. Table of existing vulnerability in the town:
Total Total of Total Kind of Hazard Vulnerability Vulnerability Vulnerability surface of housing population hazards level surface population household settlement High / Ha. % Hab. % # % Ha. # Hab. XXX Middle 6,9 6,1 95 5,8 16 5,7 High 113 277 1636 Storm water 23,7 21 298 18,2 49 17,7 flooding Middle 76,8 68 1146,8 70,1 185,3 66,8 High 13 277 1636 Drought ------Middle
The main consequences should the scenario occur are: - Most of the businesses and commercial buildings are flooded. - Contamination of the superficial and underground water due the overflow of some wells and septic tanks located in some parts of the town and overflow of the oxidation ponds. - Some roads are interrupting, preventing the access to some areas, especially to the informal settlements. - Lack of accessibility to some basics social services (schools, clinics, food and other basic services). - Relocation of affected population to the safer places into the town.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 300
Northern Regions. Flood Risk Management Plan 2011
! Population at risk Most of the population residing in Oshikuku town is at risk during a flood event, especially those living near the flood prone areas (oshanas, water canal, both sides of the Oshakati – Ruacana road). There are not exact figures of the amount of people at risk, but is around 20% of total population. If you must evacuate in the event of a flood: ! Always follow the instructions of local emergency officials. ! Take your personal emergency grab-and-go kit with you. This kit should have basic essential items such as prescription medications, eye glasses, important papers, flashlight, battery powered radio, clothing, identification and some cash. ! Ensure each family member has waterproof clothing and footwear. ! Shut and lock doors and windows, including barn doors and gates. Shut off water supply, natural gas and power to all buildings, barns, etc. as identified on farm map. ! If you are evacuating your premises, shut off your gas valve at the meter. ! Rendezvous with family and workers at designated safe meeting place or at local Emergency Services Shelter. ! Anticipated duration of emergency conditions The duration of emergency conditions depends on the weather characteristics and conditions (meteorological situation – duration and intensity of rains, volume of flood water, etc.) and on the capacity of resilience of this geographical area. ! Budget and other resources to face up to the disaster It don’t exist any special government warehouse with food supply for the affected people, but in emergency cases is used some strategical reserves from the Central Government and of some buildings belonging of Regional Council. Vulnerable people at the town must be relocated at safes houses: traditional authority buildings and schools. All the people who live in tents need time to rebuild their houses. They have officially 2 means of transportation. Main Objectives: ! Saving lives ! Preserving assets ! Preventing Mass Migration ! Ensuring access to public services for all the people ! Establishing conditions for restoring of self - reliance ! Minimize damage resulting from emergency situation
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 301
Northern Regions. Flood Risk Management Plan 2011
Program Implementation: ! Immediate Response and Evacuations Routes When the disasters appear in this town, many others means of transportation are designated for help the affected people. Some means from certain local business, private tracks and another soften transports are very useful for many critical situations. The district hospital is located at a safer land, for special attention to the town’s people affected during the disaster and emergency situation. Tarred roads are used as principal way of transportation because are safer ways. Nevertheless, most of the roads are not tarred (gravel) so they are very affected by floods with problem of accessibility principally in informal settlements. Also all of roads are affected by strong erosion that is able to destroy them. After flooding is developed a campaign in order to avoid some very often diseases like cholera, malaria, dengue, etc. that could became in a very serious epidemy. ! Long term plans In Oshikuku, they haven’t any rescue team (just the normal employers of the office of town council), or Red Cross organization and neither firefighter. It also doesn’t have any educative or informational program to prepare and train a lot of people to confront these natural hazards, like flooding. ! Preparedness and Maintenance Actions A Plan will be updated and revised systematically and it is necessary to prepare some simulation exercises to test the plan and also a proper preparation and capacitation in order to avoid big quantities damages. ! Major existing restrictions: - Inadequate skilled and trained staff in disaster management in Town Council - Lack of Town Contingency Plan - Disaster management considered an add on activity by Town Council - Lack of clear understanding of roles and responsibilities among stakeholders, even among members of the Civil Defense Committee - Lack of clear guidelines on disasters management procedures (early warning system) - Insufficient financial allocation/contingency fund for disaster management - Inadequate warehouse space - Poor public awareness on flood issues. ! Participants and partnerships in contingency planning. Early Warning System: ! Strengthen sharing disasters information locally and transboundaries
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 302
Northern Regions. Flood Risk Management Plan 2011
! Engaged traditional leaders in informatics sharing and dissemination in infrastructural development ! Improve channels of communicating the early warning system results to relevant authorities ! Channel information dissemination trough relevant authorities. At regional level however, the Namibian Disaster Management System (NDMS) appointed two senior people to oversee the coordination of the disaster response. The roles of the two senior officers were among others to: ! Provide a link between disaster response operational levels with the NDMS through weekly report to the Secretary to Cabinet (Chairperson of the National Emergency Management Committee) ! Received donations and facilitate timely distribution to the flood affected ! Continuously monitor the flood situation and facilitating the provision of appropriate response ! Coordinating transport and logistic ! Conducting weekly meetings on the flood disaster response with stakeholders ! Providing media briefs on the flood situation ! Developing medium and long term recommendation for effective flood management and rehabilitation And also, ! The Regional Councils should consider disaster management as an integral part of their activities and not an add on activity and responsibilities given to staff that have other key roles to play in the Regional Councils. ! Regional Emergency Management Units need to be continuously proactive and sensitive to the disaster risk management and should strengthen coordination among all the stakeholders before, during and after disasters. ! To facilitate coordination of disaster risk management activities (preparedness and contingency planning, public awareness, secretariat for the regional council disaster technical committee, beneficiary registration and tracking and monitoring supplies of food and not - food distribution), Regional Council should be encouraged to fill the positions of Regional Disasters Management Coordinators. Some solutions to the flood problem: Floods are a consequence of natural hydro-meteorological phenomenon, combined with their interaction with the catchment characteristics. Through interventions in changing the characteristics of the catchment the run-off processes can be altered, thereby making it possible to reduce the magnitude of the flood hazard thus generated. Urban drainage systems, made up of channels, culverts, sewers etc., are meant to prevent local floods by conveying storm water away from vulnerable sites. Mostly this is done with
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 303
Northern Regions. Flood Risk Management Plan 2011 the aim of draining storm water as fast as possible out of town. This practice may be benign in coastal cities or in agglomerations with no exposed living spaces downstream, but if cities or urban districts upstream of other riverside settlements drain storm water too quickly, this may cause urban floods downstream. Commonly it presents two major concepts of urban storm drainage: direct runoff versus source control. The latter concept suggests a number of so-called “source control measures” which are meant to either retain or reduce storm water runoff in order to prevent the exceedance of the drainage system and to mitigate the generation of flood hazards downstream. The resulting hydrographs illustrate how the reduction and retention of storm water runoff in a source control drainage systems can cut discharge peaks. The reduction of surface runoff in absolute terms can be achieved by a variety of measures that increase infiltration, evaporation and/or transpiration from the catchment areas that contribute to local flooding. The easiest way to do so is to preserve unsealed and greened spaces in the city. Such spaces are of multifunctional purpose, they: Reduce surface runoff by increasing infiltration and evapo-transpiration; Retain water through interception; Filter the percolating water; Recharge groundwater resources; Reduce air pollution and improve the urban microclimate; and Can be used for recreational purposes in the form of parks and gardens. Since the availability of space is highly limited in cities, less extensive measures that enable effective in-town infiltration can also be used. Among them are: Infiltration trenches; Soak-aways; and Measures that increase the permeability of larger surfaces. Essentially, infiltration trenches and soakaways consist of a trench or a pit filled with a top layer of permeable material like crushed stones or gravel and a bottom layer of sand. Since the potential for in-town infiltration and evapotranspiration is limited, especially in cities where convective precipitation and non-absorptive soils prevail, measures of storm water retention are vital for the mitigation of urban floods as well as for the prevention of downstream floods. Storm water retention can be achieved or facilitated by constructing basins or ponds that temporarily store surface runoff and release it subsequently at a controlled rate. There is a variety of retention basins and ponds - open or covered, wet or dry, online or offline – that may serve various purposes. The advantage of multipurpose dry ponds is the maximization of land use. They can also contribute to infiltration and to the removal of pollutants. There are many creative possibilities to use the same space for everyday activities as well as for occasional flooding. Furthermore, wet ponds in the form of artificial lakes can be of aesthetic value. Temporary storm water retention can be made in sport courts, parking sites,
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 304
Northern Regions. Flood Risk Management Plan 2011 playgrounds etc. In all cases sedimentation has to be considered a likely problem in basins and ponds. These retention basins require flow equalization facilities to prevent flooding of and damage to such facilities. A complementary multipurpose retention strategy is storm water storage as a source of water supply, so-called “rainwater harvesting”. This is particularly useful in semi-arid areas that experience water stress. Considering economic and environmental advantages and its potential for mitigation of urban floods, rainwater harvesting is not only applicable in towns where fresh water resources are scarce but constitutes a reasonable measure in almost all human settlements. Although unfiltered storm water is normally not of drinking water quality, it is amenable for non-potable purposes such as washing, irrigation, toilet flushing etc. Storm water is usually collected on roofs and stored in tanks or in underground cisterns. Implementation: The purpose of this plan is to inform and guide all the local stakeholders in the undertaking of its planning responsibilities, and in integrating and coordinating the activities of different agencies that influence the use and development of land that may be affected by natural hazards. The plan will also guide local governments, other agencies and state government of those aspects of state planning policy concerning natural hazard mitigation that should be taken into account in planning decision-making. There are many agencies that have the power to permit development that may be subject to natural hazards. While recognizing these responsibilities, this plan provides a checklist to enable the delivery of a consistent approach to natural hazard mitigation.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 305
Northern Regions. Flood Risk Management Plan 2011
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 306
Northern Regions. Flood Risk Management Plan 2011
OKAHAO TOWN FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 307 Northern Regions. Flood Risk Management Plan 2011
6.3.4.5- Okahao Town Proposals The town constitutes the second urban area in importance in the Omusati Region. There are many houses and business located in low lying areas. Main hazard is the heavy rain falls and the fact that the area is very flat with several flood prone areas within town boundaries. The rainwater stands still, due to the lack of an appropriate storm water system in place to facilitate the rapid evacuation of the water. The Development Proposals for the town will consider the identification of four major sectors, as well as the flood prone areas: Sector 1. - Existing urban area. Sector 2. - Southeastern and southwestern areas. Sector 3. - Northeastern area. Sector 4. - Northern area Land Use Proposals: Sector 1: Completion of the vacant land located within the sector, including infrastructural solution, specially the storm water drainage system. The main proposals for the sector are:
! Designing and construction of proper drainage solutions allowing the effective evacuation of rain water in Okahao Proper, avoiding further developments.
! To relocate a total of 14 houses as well as other service facilities and infrastructure in the Station 2 area
! Designing and construction of proper drainage solutions allowing the effective evacuation of rain water in Station 1. Sectors 2, 4: Planning of the future development areas of the town, including infrastructural solutions, specially the storm water drainage system. Sector 3: Development of urban agriculture activities. Flood Prone Areas: For the flood prone areas farther regulations will be established, which shall apply to all lands within the existing urban area in the floodways or flood prone areas within the zoning jurisdiction of the town of Okahao that are subject to a one percent or greater chance of flooding in any given year. The degree of flood protection required by these regulations is considered reasonable for regulatory purposes and is based on engineering and scientific methods of study. Larger floods may occur on rare occasions or the flood height may be increased by man-made or natural causes, such as ice jams and bridge openings restricted by debris. Compliance with these regulations does not imply that lands outside a floodplain or flood prone areas or uses within such areas will be free from flooding or flood damage.
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6.3.4.5.2- Okahao Town. Contingency Plan Okahao Town is located in a very flat geographical area, characterized by the presence of main natural water courses (oshanas) in surrounding areas (running from north to south in the some parts of the town). All these elements are affected by flood because of water coming from Cuvelai basin and heavy rainfall. Most of the town areas are affected, the flood water cover the flood prone areas and main access roads interrupting accessibility to some vital services (hospitals, schools, shops, etc) and other human settlements located nearby (Outapi, Oshikuku, Ruacana, Tsandi). The main problems are in the east part of the town, because the rainwater stands still because there is not a proper drainage system in place to facilitate the evacuation of the water. Scenario for planning purpose ! Hazard and resulting emergency Okahao town is affected during the rainy season by floods as consequences of heavy rainwater that inundate low lying areas within town boundaries. The emergency stated is only proclaimed by the central government. ! Likely triggers ee) Early warning indicators and triggers: They are not an early warning system. The initial warnings come from the news by TV about heavy rains at neighbor countries and some information from a Central Office of the Ministry of Agriculture and for National Meteorological forecast ff) Continuous heavy rains in the area gg) Also from INTERNET about climate and meteorological conditions in the south part of African Continent. Nevertheless, sometimes appears news at national newspaper, like in Namibian of January 18 / 2011: hh) Responsible for monitoring the early warning indicators and triggers: It is a share responsibility by the Chief Executive Officer CEO of Okahao Town Council (Focal Point) Mr. Mukulu, the councilors of affected constituencies and the Civil Defense Committee made up by stakeholders from different institutions and organizations. ! Risk analysis s) How likely is this scenario to occur? Despite of the fact that drought is the most common natural hazard to the majority of the country, during every rainy season (November – April) the area where Okahao town is located, becomes very vulnerable to flood events in a process that has seen a recurrence during the last three years. t) What will be the consequences should the scenario occur?
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 309
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The flood disasters cause damages and losses to the public and private sectors (public health and education facilities, housing business, infrastructure and others). The most terrible is the loss of human lives due to drowning and attack by wild life and crocodiles. The productive sector (agriculture, commerce – trade and markets) is highly affected (lost of crops production, commercial products, etc.). The population living on most vulnerable areas should be relocated to safer areas, requiring emergency humanitarian support (food, clothes, shelter, water and others). Normal life are disrupted, as some persons cannot come back to their normal place of living and cannot continue with their normal business of carrying a living (jobs loss, crops destroyed, or place of work destroyed). At the same time, people don’t have access to basics needs and services. As a result of that fact, is possible to obtain the following table: OKAHAO. Table of existing vulnerability in the town:
Total Total of Total Kind of Hazard Vulnerability Vulnerability Vulnerability surface of housing population hazards level surface population household settlement High / Ha. % Hab. % # % Ha. # Hab. XXX Middle 45 14,2 770,0 11,0 39,0 9,8 High 309 398 7000 Storm water 43,3 14 281,0 4,0 52 13,0 flooding Middle 263 85 5740,0 82 318 80 High 309 398 7000 Drought ------Middle
The main consequences should the scenario occur are: - Some of the businesses and commercial buildings are flooded. - Contamination of the superficial and underground water due the overflow of some wells and septic tanks, located in some parts of the town and overflow of the oxidation ponds. - Some roads are interrupting, preventing the access to some areas, especially to the informal settlements. - Lack of accessibility to some basics social services (schools, clinics, food and other basic services). - Relocation of affected population to the safer places into the town. Population at risk Most of the population residing in Okahao town is at risk during a flood event, especially those living near the flood prone areas (informal settlements, and low lying areas). There is not exact idea of the total amount of people at risk, but could be more than 1 100 Hab. (the 15% of the town). Specific vulnerable people: Disabled persons, children, old persons.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 310
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If you must evacuate in the event of a flood: ! Always follow the instructions of local emergency officials. ! Take your personal emergency grab-and-go kit with you. This kit should have basic essential items such as prescription medications, eye glasses, important papers, flashlight, battery powered radio, clothing, identification and some cash. ! Ensure each family member has waterproof clothing and footwear. ! Shut and lock doors and windows, including barn doors and gates. Shut off water supply, natural gas and power to all buildings, barns, etc. as identified on farm map. ! If you are evacuating your premises, shut off your gas valve at the meter. ! Rendezvous with family and workers at designated safe meeting place or at local Emergency Services Shelter. ! Anticipated duration of emergency conditions The duration of emergency conditions depends on the weather characteristics and conditions (meteorological situation – duration and intensity of rains, volume of flood water, etc.) and on the capacity of resilience of this geographical area. ! Budget and other resources to face up to the disaster It exist two special government warehouses belonging of Town Council with food supply for the affected people, but in emergency cases is also used some strategical reserves from the Central Government. The budget for the town in case of some kind of disaster is about $7,000 NAD. This budget should include capacity building, training and some additional information for the people in town. Vulnerable people at the town must be relocated at safes houses: traditional authority buildings and schools. All the people who live in tents need time to rebuild their houses. They have officially 2 means of transportation. Main Objectives: ! Saving lives ! Preserving assets ! Preventing Mass Migration ! Ensuring access to public services for all the people ! Establishing conditions for restoring of self - reliance ! Minimize damage resulting from emergency situation
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 311
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Program Implementation: ! Immediate Response and Evacuations Routes When the disasters appear in this town, many others means of transportation are designated for help the affected people. Some means from certain local business, private tracks and another soften transports are very useful for many critical situations. The local hospital is located at a safer land, for special attention to the town’s people affected during the disaster and emergency situation. Tarred roads are used as principal way of transportation because are safer ways. Nevertheless, most of the roads are not tarred (gravel) so they are very affected by floods with problem of accessibility principally in informal settlements. Also all of roads are affected by strong erosion that is able to destroy them. After flooding is developed a campaign in order to avoid some very often diseases like cholera, malaria, dengue, etc. that could became in a very serious epidemy. ! Long term plans In Okahao, they haven’t any rescue team (just the normal employers of the office of town council), or Red Cross organization and neither firefighter. It also doesn’t have any educative or informational program to prepare and train a lot of people to confront these natural hazards, like flooding. ! Preparedness and Maintenance Actions A Plan will be updated and revised systematically and it is necessary to prepare some simulation exercises to test the plan and also a proper preparation and capacitation in order to avoid big quantities damages. Major existing restrictions: - Inadequate skilled and trained staff in disaster management in Town Council - Lack of Town Contingency Plan - Disaster management considered an add on activity by Town Council - Lack of clear understanding of roles and responsibilities among stakeholders, even among members of the Civil Defense Committee - Lack of clear guidelines on disasters management procedures (early warning system) - Insufficient financial allocation/contingency fund for disaster management - Inadequate warehouse space - Poor public awareness on flood issues. ! Participants and partnerships in contingency planning. Okahao Town Council, Business owners, NORED, NAMPOL, NAMWATER, Schools, etc. Early Warning System:
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 312
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! Strengthen sharing disasters information locally and trans-boundaries ! Engaged traditional leaders in informatics sharing and dissemination in infrastructural development ! Improve channels of communicating the early warning system results to relevant authorities ! Channel information dissemination trough relevant authorities. At regional level however, the Namibian Disaster Management System (NDMS) appointed two senior people to oversee the coordination of the disaster response. The roles of the two senior officers were among others to: ! Provide a link between disaster response operational levels with the NDMS through weekly report to the Secretary to Cabinet (Chairperson of the National Emergency Management Committee) ! Received donations and facilitate timely distribution to the flood affected ! Continuously monitor the flood situation and facilitating the provision of appropriate response ! Coordinating transport and logistic ! Conducting weekly meetings on the flood disaster response with stakeholders ! Providing media briefs on the flood situation ! Developing medium and long term recommendation for effective flood management and rehabilitation And also, ! The Regional Councils should consider disaster management as an integral part of their activities and not an add on activity and responsibilities given to staff that have other key roles to play in the Regional Councils. ! Regional Emergency Management Units need to be continuously proactive and sensitive to the disaster risk management and should strengthen coordination among all the stakeholders before, during and after disasters. ! To facilitate coordination of disaster risk management activities (preparedness and contingency planning, public awareness, secretariat for the regional council disaster technical committee, beneficiary registration and tracking and monitoring supplies of food and not - food distribution), Regional Council should be encouraged to fill the positions of Regional Disasters Management Coordinators. Some solutions to the flood problem: Floods are a consequence of natural hydro-meteorological phenomenon, combined with their interaction with the catchment characteristics. Through interventions in changing the characteristics of the catchment the run-off processes can be altered, thereby making it possible to reduce the magnitude of the flood hazard thus generated.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 313
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Urban drainage systems, made up of channels, culverts, sewers etc., are meant to prevent local floods by conveying storm water away from vulnerable sites. Mostly this is done with the aim of draining storm water as fast as possible out of town. This practice may be benign in coastal cities or in agglomerations with no exposed living spaces downstream, but if cities or urban districts upstream of other riverside settlements drain storm water too quickly, this may cause urban floods downstream. Commonly it presents two major concepts of urban storm drainage: direct runoff versus source control. The latter concept suggests a number of so-called “source control measures” which are meant to either retain or reduce storm water runoff in order to prevent the exceedance of the drainage system and to mitigate the generation of flood hazards downstream. The resulting hydrographs illustrate how the reduction and retention of storm water runoff in a source control drainage systems can cut discharge peaks. The reduction of surface runoff in absolute terms can be achieved by a variety of measures that increase infiltration, evaporation and/or transpiration from the catchment areas that contribute to local flooding. The easiest way to do so is to preserve unsealed and greened spaces in the city. Such spaces are of multifunctional purpose, they: Reduce surface runoff by increasing infiltration and evapotranspiration; Retain water through interception; Filter the percolating water; Recharge groundwater resources; Reduce air pollution and improve the urban microclimate; and Can be used for recreational purposes in the form of parks and gardens. Since the availability of space is highly limited in cities, less extensive measures that enable effective in-town infiltration can also be used. Among them are: Infiltration trenches; Soak-aways; and Measures that increase the permeability of larger surfaces. Essentially, infiltration trenches and soakaways consist of a trench or a pit filled with a top layer of permeable material like crushed stones or gravel and a bottom layer of sand. Since the potential for in-town infiltration and evapotranspiration is limited, especially in cities where convective precipitation and non-absorptive soils prevail, measures of storm water retention are vital for the mitigation of urban floods as well as for the prevention of downstream floods. Storm water retention can be achieved or facilitated by constructing basins or ponds that temporarily store surface runoff and release it subsequently at a controlled rate. There is a variety of retention basins and ponds - open or covered, wet or dry, online or offline – that may serve various purposes. The advantage of multipurpose dry ponds is the maximization of land use. They can also contribute to infiltration and to the removal of pollutants.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 314
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There are many creative possibilities to use the same space for everyday activities as well as for occasional flooding. Furthermore, wet ponds in the form of artificial lakes can be of aesthetic value. Temporary storm water retention can be made in sport courts, parking sites, playgrounds etc. In all cases sedimentation has to be considered a likely problem in basins and ponds. These retention basins require flow equalization facilities to prevent flooding of and damage to such facilities. A complementary multipurpose retention strategy is storm water storage as a source of water supply, so-called “rainwater harvesting”. This is particularly useful in semi-arid areas that experience water stress. Considering economic and environmental advantages and its potential for mitigation of urban floods, rainwater harvesting is not only applicable in towns where fresh water resources are scarce but constitutes a reasonable measure in almost all human settlements. Although unfiltered storm water is normally not of drinking water quality, it is amenable for non-potable purposes such as washing, irrigation, toilet flushing etc. Storm water is usually collected on roofs and stored in tanks or in underground cisterns. Implementation: The purpose of this plan is to inform and guide all the local stakeholders in the undertaking of its planning responsibilities, and in integrating and coordinating the activities of different agencies that influence the use and development of land that may be affected by natural hazards. The plan will also guide local governments, other agencies and state government of those aspects of state planning policy concerning natural hazard mitigation that should be taken into account in planning decision-making. There are many agencies that have the power to permit development that may be subject to natural hazards. While recognizing these responsibilities, this plan provides a checklist to enable the delivery of a consistent approach to natural hazard mitigation.
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Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 316
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OSHAKATI. CONCEPT MASTER PLAN. PHASE 1 FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 317 Northern Regions. Flood Risk Management Plan 2011
7.0- OSHAKATI TOWN CONCEPT MASTER PLAN. PHASE 1
7.1- Proposal of Implementation Oshakati is seriously affected by annual flooding, problem that is getting worse each year since the town is expanding, so more houses and company buildings are suffering from these floods every year. In fact, Oshakati is, at the present time, the most vulnerable urban center in the whole country to flood events. In the year 2008 a Concept Master Plan for Oshakati was prepared by BAR (Buro of Architecture), a Belgian Consultant firm, with the objective to create a tool for the local authorities to deal with the flood problem and, simultaneously, organize, build and maintain the town as a modern and comfortable place to live and work. The Concept Master Plan will allow the implementation of solutions to aspects such as flooding, relocating people, water and power supply, sewerage and waste water treatment. At the same time, the Concept Master Plan is intended to be expanded, and include the town of Ongwediva, so the two towns will benefit and the government will save a lot of funds by collective studies of water treatment, power supply, zoning of industry, educating programs, public transportation, etc. The implementation of the Concept Master Plan requires the identification of a set of necessary tasks and activities to be carried out in a preliminary phase. The most important purpose of this report is the identification of the main tasks and activities to be carried out in an initial stage (Phase 1) that allow the implementation of the Concept Master Plan for the town of Oshakati and, at the same time, the mitigation Flooded areas in Oshakati town of the impact of the flood events in the near future. The town of Oshakati is the capital of the most densely populated Oshana Region; it is the most developed town in the area covered by the Cuvelai basin in northern Namibia. Since Namibia achieved independence in 1990, Oshakati has experienced much development, so business and trade are now vital elements in the economy. Oshakati is comprised of four general areas and numerous extensions and informal settlements. The four general areas include Oshakati West, Oshakati East, Oshakati North, and the Industrial Area. Oshakati North is currently undeveloped and being re-planned to accommodate the flood zone. According to the national census of 2000, the population of the town was at that time 42000 Sky Bridge inhabitants. The population growth in the Oshana region is projected to be 1.8 %. It is estimated that the actual growth rate in Oshakati is much higher than in the rest of the Region, so the national growth rate of 2.6% could be used. According to this, the present population of the town is estimated between 50000-55000 inhabitants.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 318
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During flood events, large parts of the town are submerged for many weeks, affecting a huge number of residents. The degree of affectations is very high. The concentration of a large number of population, business, and infrastructure in a very vulnerable area to floods is a permanent hazard for the town. The most important elements that increase the vulnerability to flood events in Oshakati are related to the low capacity and obstruction of existing culverts and bridges (Sky bridge, Kandjengedi bridge), shallow oshanas, which provoke flooding of nearby zones, presence of informal settlements and buildings in natural water ways and in flood prone areas (Oshoopala, Sky), as well as the obstruction of natural water ways by debris, garbage, vegetation and inadequate digging. The informal settlements (Oshoopala, Uupindi, Oneshila and Sky) are the most affected areas. The sewage system is also affected, with some pump stations under water, while the oxidation ponds are overflowed and damaged. OSHAKATI TOWN CONCEPT MASTER PLAN. PHASE 1 The Concept Master Plan comprises a large number of proposals and actions that will require a vast amount of financial support and time. Nevertheless, it is possible, and recommended to start the execution of a group of tasks and activities that will facilitate the future implementation of the whole Concept Master Plan in perfectly timed phases. According to this, it is possible to identify within the Phase 1 three main tasks, subdivided into nine different activities: Activity 1: Compensation of traditional houses. The areas within the proclaimed townlands located on the northern side of the town, mostly high lands, are still occupied by traditional houses (homesteads) and communal farms. There is an urgent need to complete the legal process to facilitate the compensation of the land owners and make the areas available for the future town development, in especial to relocate the population living in flood prone areas. Activity 2: Environmental Impact Assessment. The implementation of the Master Plan requires an exhaustive analysis of the impacts of the proposed works on the environment. Activity 3: Servicing of extensions 4, 5, 6 and Ekuku area. With the purpose of allow the relocation of population living in vulnerable areas to flood events, it is essential to provide in advance the required technical infrastructure (water supply, sewerage, electricity, roads and drainage) to the land allocated to that purpose, in this case the extensions 4, 5, 6 and the Ekuku area. Activity 4: Relocation of vulnerable population. Once the necessary conditions are completed in the zones designed for new residential developments in the north side (extensions 4, 5, 6 and Ekuku area), it will be possible to initiate the gradual relocation of the residents in flood pone areas, ensuring that no unplanned development should be permitted in those places, especially the settlement of new population.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 319
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Activity 5: Deepening of the Okatana River (oshana). This activity will comprises the information gathering, design, tender and carrying out of the necessary works in order to improve the natural water way to facilitate water evacuation and mitigate damages to nearby areas. The proposal could include the identification and removal of constructions located in the area under project. Activity 6: Modification of Kandjengedi and Sky bridges. This activity will comprises the information gathering, design, tender and construction activities to increase capacity of both bridges to accommodate flood and storm waters. Activity 7: Expansion of two lanes road until Ongwediva. The enlargement of the Kandjengedi Bridge should consider also the increase of the road section (two lanes) in order to improve the traffic flow, considering this expansion along the main road from Oshakati to Ongwediva, improving the connection between these two major urban areas. Activity 8: Construction of a new activated sludge treatment plant. Oxidation ponds with final water evaporation have proved to be vulnerable structures during flood events. Many of these systems break and/or overflow, spilling raw or insufficiently treated sewage into the surrounding, lower lying, densely populated areas, turning out to be a serious health hazard. Additionally, several sewerage pump stations are under water during the floods. To provide safer living conditions for the population living in areas at risk, especially in the major urban centers, the oxidation ponds should be replaced with modern biological treatment technology in the form of a new single activated sludge plant, which will serve both Oshakati and Ongwediva in a first phase, and Ondangwa in a subsequent stage. Activity 9: Construction of the dike around town proposed by the Master Plan: To avoid future flooding, a 45km long and 2m high dike with an integrated 4 lane road needs to be constructed around the existing town with controlled locks and an adequate buffer zone below the urban area. The ring road will also protect the town centre from heavy and through - traffic. The natural rivers inside the town will be channeled and will have a controlled water level year-round. The designed dike protects also Ongwediva from the flooding water.
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 320
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7.2- Time framework
Time Schedule/Months Estimated Activities Actions Description Costs 01 02 03 04 05 06 07 08 09 10 11 12 Compensation of traditional houses 0101 Create awareness among land owners 01 0102 Land valuation 0103 Actual compensation TOTAL ACTIVITY Environmental Impact Assessment of Concept Master Plan 0201 Preparation of TOR. Scope identification 02 0202 Appointment of Consultant 0203 Preparation of EIA TOTAL ACTIVITY Servicing of extensions 4, 5, 6 and Okaku and Ekuku areas 0301 Land surveying 0302 Tendering (design) 0303 Detailed design of extensions 03 0304 Tendering (construction activities) 0305 Construction of necessary services TOTAL ACTIVITY Relocation of vulnerable population 0401 Verification of vulnerable population 0402 Identification of the prioritized areas 0403 Improvement of sanitation-informal 04 areas 0404 Improvement of sewerage and ponds 0405 Relocation of vulnerable population TOTAL ACTIVITY Time Schedule/Months Estimated Activities Actions Description Costs 01 02 03 04 05 06 07 08 09 10 11 12 Improvement of natural water ways 0501 Consultation with stakeholders 0502 Appointment of Consultant. Tendering 05 0503 Preparation of project 0504 Tendering (construction activities) 0505 Project implementation TOTAL ACTIVITY Modification of bridges (Kandjengedi, Sky, OPE, Ekuku – Ehenye and Okatana-Ongwediva-Endola) and two-lane road expansion 06 0601 Technical debate on proper solutions 0602 Tendering (design
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of bridges and road) 0603 Preparation of projects (bridges and road) 0604 Tendering (construction) 0605 Construction activities(bridges and road) TOTAL ACTIVITY Design and construction of dike 0701 Tendering (design of dike) 0702 Preparation of outline proposal 0703 Preparation of Terms of Reference 0704 Preparation of 07 specific EIA 0705 Preparation of final project 0706 Tendering (construction of dike) 0707 Construction of dike TOTAL ACTIVITY Construction of new treatment plant 0801 Preparation of Terms of Reference 0802 Preparation of specific EIA 08 0803 Tendering (construction of plant) 0804 Construction of new treatment plant TOTAL ACTIVITY TOTAL PHASE 1
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7.3- Action Plan
Activities Actions Description Stakeholders Date Compensation of traditional houses Create awareness among land owners about the Oshakati Town Council, importance to transfer land ownership to local 0101 Traditional Leaders, authorities in order to relocate population living in Oshana Regional Council 01 flood prone areas 0102 Land valuation Ministry of Lands Oshakati Town Council, 0103 Actual compensation Oshana Regional Council, Ministry of Lands Environmental Impact Assessment of Concept Master Plan MRLGHRD, Oshakati Town Council, Oshana Regional Council, Preparation of Terms of Reference. Identify 0201 Ministry of Environment, scope of the Environmental Impact Assessment Ministry of Agriculture, 02 NAMWATER, Roads Authority Appointment of Consultant to carry out the 0202 Oshakati Town Council assessment Preparation of Environmental Impact 0203 Consultant Assessment Servicing of extensions 4, 5, 6 and Okaku and Ekuku areas Surveying of the land allocated for the relocation 0301 Oshakati Town Council of population residing in flood prone areas 0302 Tendering (design) Oshakati Town Council 03 Detailed design of the proposed extensions: new 0303 Consultant residential areas, including necessary services 0304 Tendering (construction activities) Oshakati Town Council 0305 Construction of necessary services Consultant Activities Actions Description Stakeholders Date Relocation of vulnerable population Verification of exact number of population 0401 residing in flood prone areas that need to be Oshakati Town Council relocated Identification of the prioritized areas (Ushoopala, 0402 Eemwandi, Sky and any other area seriously Oshakati Town Council affected by flood or new proposals) 04 Improvement of sanitation in the informal 0403 Oshakati Town Council settlements Improvement of the sewerage system, including 0404 Oshakati Town Council upgrading of existing oxidation ponds Phased relocation of vulnerable population to the 0405 new areas once necessary services are Oshakati Town Council constructed by stages Improvement of natural water ways Oshana Regional Council, Oshakati Town Council, Ministry of Environment, 0501 Consultation with stakeholders Ministry of Agriculture, NAMWATER, Roads Authority Appointment of Consultant to carry out the 0502 Oshakati Town Council preparation of the required project. Tendering. Preparation of project, considering all necessary 0503 activities (deepening of rivers, removal of existing Consultant (design) 05 obstructions, improvement of local drainage) 0504 Tendering (construction activities) Oshakati Town Council Project implementation – construction activities: Deepening of rivers. Removal of structures, debris, garbage and vegetation. Improvement of local drainage 0505 Consultant (construction)
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Activities Actions Description Stakeholders Date Modification of bridges (Kandjengedi, Sky, OPE, Ekuku – Ehenye and Okatana-Ongwediva-Endola) and two-lane road expansion Oshakati Town Council, Technical debate on proper solutions for the Ongwediva Town Council, design of selected bridges and two-lane road Oshana Regional Council, 0601 expansion from Kandjengedi bridge to MRLGHRD, Roads Authority, Ongwediva. Knight Piesold, UWP, 06 Bicon Namibia 0602 Tendering (design) Oshakati Town Council Preparation of projects of selected bridges and 0603 two-lane road expansion from Kandjengedi Consultant bridge to Ongwediva. 0604 Tendering (construction) Oshakati Town Council Construction activities (bridges and two-lane 0605 Consultant (construction) road) Design and construction of dike 0701 Tendering (design of the dike) Oshakati Town Council 0702 Preparation of outline proposal of proposed dike Consultant (design) MRLGHRD, Oshakati Town Council, Oshana Regional Council, Ministry of Environment, 0703 Preparation of Terms of Reference 07 Ministry of Agriculture, NAMWATER, Roads Authority, Traditional Leaders 0704 Specific Environmental Impact Assessment Consultant (EIA) 0705 Preparation of final project Consultant (design) 0706 Tendering (construction of dike) Oshakati Town Council 0707 Construction of dike Consultant (construction) Construction of new treatment plant MRLGHRD, Oshakati Town Council, Ongwediva Town 0801 Preparation of Terms of Reference Council, 08 Oshana Regional Council, Ministry of Environment 0802 Specific Environmental Impact Assessment Consultant (EIA) 0803 Tendering (construction of plant) Oshakati Town Council 0804 Construction of new treatment plant Consultant (construction)
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7.4- Construction of dike around Oshakati town
7.4.1- Standard Summary project 1. BASIC INFORMATION 1.1 Title: Dike around Oshakati Town. 1.2 Sector: Infrastructure (IN), Environment (EN) 1.3 Location: Oshakati Town, Oshana Region 1.4 Beneficiary: Oshakati Town Council. 2. OBJECTIVES 2.1 Overall Objective(s): · Avoid future flooding in the Oshakati Town urban area; · Improvement of the accessibility of the Oshakati Town, with an integrated 4 lane road to be constructed around the existing town; · The ring road will also protect the town centre from heavy and through - traffic. 2.2 Project purpose: · Defense against flooding into Oshakati Town urban area. 2.3 Project priority: Medium-term priority: There is an urgent need to mitigate the flood impact on the urban areas of Oshakati Town, preserving human lives and properties, promoting a safe and favorable business environment to stimulate national and international trade in the area. 2.4 Regional and Local Impacts The main impacts of the project consist in: ! Prevention of the flood disasters in a major urban center; ! Improvement of the traffic conditions in the area; ! Development of new economic activities at local and regional level; ! Provision of new urban areas for future development. 3. DESCRIPTION 3.1 Background and justification: Oshakati is seriously affected by annual flooding, problem that is getting worse each year since the town is expanding, so more houses and company buildings are suffering from these floods every year. In fact, Oshakati is, at the present time, the most vulnerable urban center in the whole country to flood events. In the year 2008 a Concept Master Plan for Oshakati was prepared by BAR (Buro of Architecture), a Belgian Consultant firm, with the objective to create a tool for the local authorities to deal with the flood problem and, simultaneously, organize, build and maintain the town as a modern and comfortable place to live and work. The Concept Master Plan will allow the implementation of solutions to aspects such as flooding, relocating people, water and power supply, sewerage and waste water treatment. At the same time, the Concept Master Plan is intended to be expanded, and include the town of
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Ongwediva, so the two towns will benefit and the government will save a lot of funds by collective studies of water treatment, power supply, zoning of industry, educating programs, public transportation, etc. 3.2 Linked activities: a) Compensation of traditional houses. The areas within the proclaimed townlands located on the northern side of the town, mostly high lands, are still occupied by traditional houses (homesteads) and communal farms. There is an urgent need to complete the legal process to facilitate the compensation of the land owners and make the areas available for the future town development, in especial to relocate the population living in flood prone areas. b) Environmental Impact Assessment. The implementation of the Master Plan requires an exhaustive analysis of the impacts of the proposed works on the environment. c) Servicing of extensions 4, 5, 6, Okaku and Ekuku area. With the purpose of allow the relocation of population living in vulnerable areas to flood events, it is essential to provide in advance the required technical infrastructure (water supply, sewerage, electricity, roads and drainage) to the land allocated to that purpose, in this case the extensions 4, 5, 6, Okaku and the Ekuku area. d) Relocation of vulnerable population. Once the necessary conditions are completed in the zones designed for new residential developments in the north side (extensions 4, 5, 6, Okaku and Ekuku area), it will be possible to initiate the gradual relocation of the residents in flood pone areas, ensuring that no unplanned development should be permitted in those places, especially the settlement of new population. e) Improvement of natural water ways. This activity will comprises the information gathering, design, tender and carrying out of the necessary works in order to improve the natural water way to facilitate water evacuation and mitigate damages to nearby areas. The proposal could include the identification and removal of constructions located in the area under project. f) Modification of bridges (Kandjengedi, Sky, OPE, Ekuku – Ehenye and Okatana-Ongwediva- Endola) and two-lane road expansion This activity will comprises the information gathering, design, tender and construction activities to increase capacity of both bridges to accommodate flood and storm waters. The enlargement of the Kandjengedi Bridge should consider also the increase of the road section (two lanes) in order to improve the traffic flow, considering this expansion along the main road from Oshakati to Ongwediva, improving the connection between these two major urban areas. g) Construction of a new activated sludge treatment plant. Oxidation ponds with final water evaporation have proved to be vulnerable structures during flood events. Many of these systems break and/or overflow, spilling raw or insufficiently treated sewage into the surrounding, lower lying, densely populated areas, turning out to be a serious health hazard. Additionally, several sewerage pump stations are under water during the floods. To provide safer living conditions for the population living in areas at risk, especially in the major urban centers, the oxidation ponds should be replaced with modern biological treatment technology in the form of a new single activated sludge plant, which will serve both Oshakati and Ongwediva in a first phase, and
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Ondangwa in a subsequent stage. 3.3 Results: · Project technical design and associated documents (tender documents); · Construction of a dike with an integrated road around the existing town; · Creation of a wide protected area against the floods; · Supervision reports, endorsement of payments certificates. 3.4 Activities: In order to achieve the project completion, the following activities will be developed: Component 1 – Technical project design and project preparation Preparation of the necessary technical plans and tender documents for the work contracts, including engineering design, technical specifications and Terms of Reference. Component 2 – Project implementation/works contract The necessary works to be undertaken are: ! assess, revise and estimate the overall cost of the proposed flood control works; ! verify topographic surveys and subsequent mapping carried out in selected areas; ! comment on the capacity of the Oshakati Town Council to implement the project. ! assess the environmental impact of the proposed works and any mitigation measures required; ! construction of a 45km long and 2m high dike with an integrated 4 lane road around the existing town with controlled locks and an adequate buffer zone below the urban area. Component 3 – Work supervision and reporting The Oshakati Town Council will be responsible for the selection of the Consultant/Engineer for the supervision of works under component 2. The Consultant/Engineer will be appointed following tender procedures for the supervision contracts according to the “General Conditions of Contract for Works of Civil Engineering Construction”. 3.5 Lessons learned: Experiences from other projects related with the proposed dike for Oshakati Town, shows: ! Costs have to be realistically estimated and time schedules properly observed in order to assure a successful implementation of the project. ! The benefit of intense communication and co-operation between all relevant parties involved. ! The problems and aspects have been discussed with the involved institutions and beneficiaries and accordingly corrective measures were taken as regards to the technical, administrative, finance aspects. ! As from the technical and administrative domains are concerned, it is requested that the National legislation is to be fully reflected in the tender documentation, technical studies and specifications. ! Impact assessment studies and other relevant documents were requested before any project is proposed by the beneficiaries.
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! The problem of poor design and technical project against ambitious expectations of the beneficiaries were seriously discussed as to avoid further non results of the project and loss of financial backing. The following aspects were also stressed on: a. projects are to be realistic as they are to be used 100 % from the capacity; b. training for the utilization and also for the maintenance and the spare parts necessities are to be taken into account by the beneficiaries; c. equipment and technical specifications are to be compatible as for the both parts involved are concerned. Otherwise the project and the subsequent activities are compromised. As for the efficiency is concerned, taking into account that a large number of institutions are involved (line ministries, agencies and subordinated organizations) is necessary to deeply implicate all in the relevant activities in order to obtain better outputs, Regarding the financial aspects the beneficiaries were advised taking into account the previous experience to open a parallel account for the co-financed activities in order to better survey the full development of the project. 4. INSTITUTIONAL FRAMEWORK Beneficiary: Oshakati Town Council Engineer: The Engineer will be appointed following tender procedure for the supervision contract(s) according to the “General Conditions of Contract for Works of Civil Engineering Construction” Contracting Authority: Oshakati Town Council
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7.4.2- Terms of Reference 1 INTRODUCTION 1.1 BACKGROUND The Consultant will prepare and submit an Environmental Impact Assessment (EIA) report to explain the environmental effects of the construction and operation of the proposed dike to be constructed around Oshakati Town. The Project is the construction of a 45km long and 2m high dike with an integrated 4 lane road needs to be constructed around the existing town with controlled locks and an adequate buffer zone below the urban area. The ring road will also protect the town centre from heavy and through - traffic. The natural rivers inside the town will be channeled and will have a controlled water level year-round. The designed dike protects also Ongwediva from the flooding water. The purpose of this document is to identify for the Consultant and appropriate stakeholders the information required by government agencies for an Environmental Impact Assessment report. 1.2 SCOPE [A] The Consultant will prepare and submit an EIA report that examines the environmental and socioeconomic effects of the construction of a dike around the Oshakati town urban area to avoid future flooding. [B] The Study Area for the EIA shall include the Project Area, as well as, the spatial and temporal limits of individual environmental components outside the Project Area boundaries where an effect can be reasonably expected. The Study Area includes both the Local Study Area and Regional Study Area. [C] The EIA report shall be prepared with consideration to all applicable national legislation, codes of practice, guidelines, standards and directives. The Consultant must identify the legislation, policies, approvals and current multi-stakeholder planning initiatives applicable to the review of this Project. [D] The EIA report shall be prepared in accordance with these Terms of Reference. [E] The EIA report will include a glossary of terms and a list of abbreviations to assist the reader in understanding the material presented. It will also include concordance tables that cross-reference the report to the sub-section level of the EIA Terms of Reference. 2 PROJECT DESCRIPTION 2.1 THE PROPONENT [A] Provide: a) a corporate profile; and b) the name of the legal entity that will develop, manage and operate the Project and hold the operating approvals. [B] Describe the Consultant’s background and experience in the preparation of similar studies. 2.2 THE PROJECT [A] Describe the construction and operation of the proposed dike, including: a) purpose of the dike; b) location, size (areal extent), and design; c) compliance with safety regulations;
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Northern Regions. Flood Risk Management Plan 2011 d) construction timeframe; e) source and type of construction materials; f) solid and liquid materials balance for inflows and outflows, including a description of the sources and disposal areas of the inflows and outflows, respectively; g) expected timeframes for operation; h) source and type of soil and vegetation reclamation materials; i) planned reclamation outcomes (land use, capability, wildlife habitat); j) air, water and terrestrial monitoring programs; and k) wildlife deterrent programs.
2.3 EVALUATION OF ALTERNATIVES [A] Discuss the need for the Project addressing: a) the suitability of the dike site; b) any alternative means of carrying out the Project that are technically and economically feasible and where applicable indicate their potential environmental effects and impacts; c) the reasons for not selecting any identified alternatives; d) contingency plans if the Project does not perform as expected; and e) implications resulting from a delay in proceeding with the Project, or any phase of the Project. [B] Discuss the implications of not going ahead with the Project. 2.4 CONSERVATION AND RECLAMATION [A] Provide a conceptual conservation and reclamation plan for the Project with consideration to: a) pre-development information; b) integration of operations, reclamation planning and reclamation activities; c) discuss any constraints to reclamation; d) post-development land capability; e) a re-vegetation plan; f) reclamation material salvage, storage areas and handling procedures; g) pre-development and final reclaimed drainage plans; h) integrating surface and near-surface drainage within the Project Area; and i) promotion of biodiversity. [B] Provide: a) a conceptual ecological land classification (ELC) map for the post-reclamation landscape; b) if the reclamation plan includes wetland ecosystems, a discussion of issues related to the design of a self sustaining and productive aquatic ecosystem for a range of end users and uses; and c) a discussion of uncertainties related to the conceptual reclamation plan.
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2.5 ENVIRONMENTAL MANAGEMENT SYSTEMS [A] Summarize key elements of Consultant’s existing or proposed environmental, health and safety management system. [B] Describe adaptive management plans that minimize the impact of the Project. Describe the flexibility built into the dike design and layout to accommodate future modifications required by any change in environmental standards, limits and guidelines. [C] Provide a conceptual plan to monitor reclamation performance and success. [D] Discuss how the results of monitoring programs and publicly available monitoring information will be integrated with the environmental management system for the Project.
3 ENVIRONMENTAL ASSESSMENT 3.1 MODELLING [A] For each model used in the assessment, provide: a) justification for the model used; b) documentation of the assumptions used to obtain the modeling predictions; and c) a discussion of the limitations of the models used and how these limitations were addressed, including sources of error and relative accuracy. 3.2 POTENTIAL IMPACTS [A] Summarize expected changes to the Project Area arising from the Project, including: a) impact significance in terms of magnitude, extent, duration, frequency and reversibility; b) the approved footprint (areal extent, elevations and slopes); c) operating life; d) reclamation outcomes (land use, capability, wildlife habitat); [B] Summarize expected changes to the area outside the Project Area, including: a) expected flows in reclaimed watercourses and waterbodies, including need for new watercourses or waterbodies or removal of planned watercourses or waterbodies; b) changes in air emissions (type, rate, source, distribution); and c) changes to other parts of the existing oshanas, including water balances, reclamation material balances and timing and outcomes of reclamation. [C] Describe the potential environmental impacts arising from the construction of the dike at the Project, local and regional scales, with specific reference to: a) air quality; b) groundwater quality; c) hydrology; d) surface water quality; e) aquatic ecology (including fish and fish habitat); f) vegetation;
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Northern Regions. Flood Risk Management Plan 2011 g) wildlife; and h) biodiversity. [D] Describe how the impacts were assessed, including a discussion on how the Local Study Area and Regional Study Area for each impact were determined, and the confidence in the assessments. [E] Describe potential cumulative impacts to and by other current and planned activities in the region, with particular reference to adjacent activities. 3.3 MITIGATION [A] Discuss measures planned to mitigate the impacts of construction and operation of the dike at the Project, local and regional scales. [B] Describe the residual impacts of the Project and Consultant’s plans to manage those effects. 3.4 MONITORING [A] Discuss any changes to existing monitoring programs or additional monitoring programs the Consultant will conduct to evaluate project impacts and mitigation efforts. [B] Discuss Consultant’s regional monitoring activities and involvement in regional and cooperative efforts to address environmental and socio-economic issues. 4 PUBLIC ENGAGEMENT AND LOCAL CONSULTATION [A] Document the public engagement program implemented for the Project, including: a) description and documentation of concerns and issues expressed by the public, Consultant’s analysis of those concerns and issues, and the actions taken to address those concerns and issues; and b) how public input was incorporated in the Project development, impact mitigation and monitoring. [B] Document the local consultation program implemented for the Project, including: a) description and documentation of concerns and issues expressed by local communities and groups, Consultant’s analysis of those concerns and issues, and the actions taken to address those concerns and issues; b) how local community input was incorporated into the Project development, impact mitigation and monitoring; and c) consultation undertaken with local communities and groups with respect to traditional ecological knowledge and traditional use of land. [C] Describe plans to maintain the public engagement and local community consultation process following completion of the EIA review to ensure that the public and local populations have an appropriate forum for expressing their views on the ongoing development, operation and reclamation of the Project. 5 TRADITIONAL ECOLOGICAL KNOWLEDGE AND LAND USE [A] Describe the extent of traditional use of land in the Local Study Area. Discuss vegetation and wildlife used for traditional food, ceremonial, medicinal and other purposes, and any potential effects the Project may have. [B] Identify how traditional ecological knowledge was gathered and incorporated into the
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Northern Regions. Flood Risk Management Plan 2011 assessment. [C] Determine the impact of the Project on traditional uses and identify possible mitigation strategies. 6 HISTORIC RESOURCES [A] Summarize existing historic resource issues for the Project. [B] Assess potential for further historic resource issues for the Project. [C] Recommend management of historic resource issues for the Project. [D] Describe consultation with Oshakati Town Council and Oshana Regional Council concerning historic resource requirements for the Project. [E] Document any stakeholder concerns with respect to the development of the Project based on the historic significance of the Study Area. 7 PUBLIC HEALTH AND SAFETY ASSESSMENT [A] Describe those aspects of the Project that may have implications for public health or the delivery of local and regional health services. Determine whether there may be implications for public health arising from the Project. Specifically, where appropriate: a) assess the potential health implications of the compounds that will be released to the environment from the proposed Project in relation to exposure limits established to prevent acute and chronic adverse effects on human health; b) provide the data, exposure modeling calculations, and describe the methods the Consultant used to assess impacts of the Project on human health and safety; c) provide information, including chemical analyses and modeling results, on samples of selected environmental media (e.g., soil, water, air, vegetation, wild game, etc.) used in the assessment; d) discuss the potential for changes to water quality, air quality and soil quality to increase human exposure to contaminants taking into consideration all Project activities; e) identify the human health impact of the potential contamination to country foods and natural food sources taking into consideration all Project activities; f) document any health concerns raised by stakeholders during consultation on the Project; g) document any health concerns identified by local communities or groups due to impacts of existing development and of the Project specifically on their traditional lifestyle and include an local receptor type in the assessment; h) assess the cumulative human health effects to receptors; i) as appropriate, describe anticipated follow-up work, including local and regional cooperative studies. Discuss how such work will be implemented and coordinated with ongoing air, soil and water quality initiatives; j) describe the potential health impacts due to higher regional traffic volumes and the increased risk of accidental leaks and spills; and k) discuss mitigation strategies to minimize the potential impact of the Project on human health. [B] Describe those aspects of the Project that may have implications for public safety. Determine whether there may be implications for public safety arising from the Project. Specifically:
Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 333
Northern Regions. Flood Risk Management Plan 2011 a) describe Consultant’s emergency response plan, including public notification protocol and safety procedures, that will be used to minimize adverse environmental effects, while protecting the safety of personnel; b) document any safety concerns raised by stakeholders during consultation on the Project; c) describe how local residents will be contacted during an emergency and the type of information that will be communicated to them; d) describe the existing agreements with local authorities, public health facilities and local emergency response agencies; e) describe the potential safety impacts due to higher regional traffic volumes; and f) discuss mitigation plans to ensure workforce and public safety during the life of the Project from accidental release or spill of chemicals to the environment and failures of structures retaining water or fluid wastes. 8 SOCIO-ECONOMIC ASSESSMENT [A] Describe the socio-economic effects of construction and operation of the Project, including: a) impacts related to: i) employment, ii) regional and local economic benefits; and iii) effects on traditional land use and culture; b) estimated total Project cost, including a breakdown for engineering and project management, equipment and materials, and labor for both construction and operation stages. Indicate the percentage of expenditures expected to occur in the region, outside of Oshana, and outside of Namibia; and c) the impact on local and regional infrastructure and community services, including consideration of local and regional “hard services”, education/training services, social services, urban and regional recreation services, law enforcement, affordable housing, health care services and emergency services. [B] Describe anticipated changes to traffic (e.g., type, volume) on roads during the life of the Project. Consider other existing and planned uses of the same roads. Identify needs to upgrade existing roads and intersections or construct new roads. [C] Identify components of the Project that have the potential to increase noise levels and discuss the implications. Present the results of a noise assessment. Include: a) potentially-affected people and wildlife; b) an estimate of the potential for increased noise resulting from the development; and c) the implications of any increased noise levels. [D] Discuss options for mitigating impacts including: a) Consultant’s policies and programs regarding the use of local and regional goods and services; b) plans to work with Traditional Authorities and local communities and groups and other local residents and businesses regarding employment, training needs, and other economic development opportunities arising from the Project;
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Northern Regions. Flood Risk Management Plan 2011 c) the potential to avoid overlap with other Projects that are reasonably anticipated during the life of the Project; and d) strategies to mitigate socio-economic concerns raised by the local government and other stakeholders in the region. [E] Describe the residual effects of the Project on socio-economic conditions and Consultant’s plans to manage those effects. [F] Discuss monitoring plans proposed to measure the success of mitigation activities
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Northern Regions. Flood Risk Management Plan 2011
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PROPOSALS FOR FUTURE PLANNING Study Case: Outapi Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 344 Northern Regions. Flood Risk Management Plan 2011
8.0- PROPOSALS FOR FUTURE PLANNING. Study Case: Outapi The Development Proposals for the town of Outapi are prepared considering avoiding the flood risk where possible, substituting less vulnerable uses where avoidance is not possible, and mitigating and managing the risk where avoidance and substitution are not possible. The Development Proposals include the following aspects: ! Preparedness, maintenance and flood mitigation actions in the identified areas at risk, ! Land use projections ! Functional structure for undeveloped land within town boundaries, ! General planning proposals and ! Regulations for future development, ! Infrastructure solutions (roads, water supply, sewerage, drainage).
Objective: To create a tool for the local authorities to deal with the flood problem and, simultaneously, organize, build and maintain those towns and settlement areas as modern and comfortable places to live and work. The Development Proposals will allow the implementation of solutions to aspects such as flooding, relocating people, water and power supply, sewerage and waste water treatment in each of the selected human settlements. The input of international experience and knowledge, environmental aspects, economic impact and social objectives resulted in a general land use proposal for the town with advanced functional layers, several zones and perfectly timed phases.
Drawing up a plan for the extension of the existing town of Outapi, was done on a basis of a program that takes into account functional relations, general ideas connected to the town and the original purposes; the plan needs also to be flexible, in order to fit ideas, needs and technological innovations that will appear during the construction.
General balance of urban areas
Urban Land Uses Area (Ha.) Industrial area 104.8 Special area 62.7 Oxidation Pond (and buffer area) 5.6 Business and office area 108.8 Civic area 23.2 Local Authority area 6.2 Public Open Space 62.8 Agricultural area 110.8 Institutional area 33.2 Oshanas to be deepened 123.1 General Residential area 9.3 Residential area 660.0 Buffer Green area 188.2 Total: 1498.7
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Main proposals:
! Kasikili west: Trade Fair area (17.15 hectares).
! Formalization of informal settlements:
- Onhimbu West.
- Oukwa - Wananyanga
- Opa Okakwa (East of Kasikili)
! Bridges in the Tsandi road need to be widened.
! Construction of Prison Headquarters and Correctional Services (offices, sports fields, accommodation, garden area, penitentiary). Traditional houses located in the area need to be relocated and compensated.
! All the streets should be designed with sidewalks.
! Bus and taxi terminal: There is a land allocated in the Ruacana – Oshakati road.
! Designing of main accesses to town.
Main land uses:
South West (outside existing township boundaries): Urban agricultural/ Sports facilities/ Public open space (flood prone area). In the area there are traditional houses with mahangu fields that need to be compensated.
South East (inside existing township boundaries): Higher Education, Heavy Industry, Light Industry, Residential (high income), General Residential.
North of Tobias Hainyeko & Onhimbu: 2 Primary Schools, Business.
The water canal should be underground the whole portion within town boundaries.
The agriculture district: The southwestern part of the town will have a special zone for agricultural activities.
This area will benefit from the controlled water environment and will increase the diversity and succession of nourishment.
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8.1- Flood Regulations for existing urban area (These Flood Regulations were prepared in order to be presented to Outapi local authorities and specialists for their approval, but that phase was not possible to carry out due to reasons not accountable to the Team of Experts).
The regulations describe in this chapter are known as the Flood Regulations for Existing Urban Area of the Outapi Town. The regulations shall apply to all lands within the Existing Urban Area in the floodways or flood prone areas within the zoning jurisdiction of the town of Outapi that are subject to a one percent or greater chance of flooding in any given year. The degree of flood protection required by this chapter is considered reasonable for regulatory purposes and is based on engineering and scientific methods of study. Larger floods may occur on rare occasions or the flood height may be increased by man-made or natural causes, such as ice jams and bridge openings restricted by debris. Compliance with these regulations does not imply that lands outside a floodplain or flood prone areas or uses within such areas will be free from flooding or flood damage. Definitions. Base Flood shall mean the flood having a one percent chance of being equaled or exceeded in any given year. Basement shall mean any enclosed area having its floor below grade level on all sides. Development shall mean any man-made change to improved or unimproved real estate, including but not limited to, buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations, or storage of equipment or materials. Development area shall mean the entire site of a proposed development or improvement. Existing Urban Area shall mean those areas inside the boundaries of the town of Outapi. Floodplain shall mean those lands which are subject to a one percent or greater chance of flooding in any given year. Flood prone area shall mean those lands subject to a one percent or greater chance of flooding in any given year, as determined by hydrologic and hydraulic studies completed by the Town Council or other government agency, or other acceptable source as approved by the Town Council where this is the best available information. Flood proofing shall mean any combination of structural and nonstructural additions, changes, or adjustments to structures which reduce or eliminate flood damage to real estate or improved real property, water and sanitary facilities, structures and their contents. Floodway shall mean the channel of a river or other watercourses and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than one foot. Lowest floor shall mean the lowest floor of the lowest enclosed area (including basement). An unfinished or flood-resistant enclosure, usable solely for parking of vehicles or building access, in an area other than a basement area is not considered a building's lowest floor; provided that such enclosure is not built so as to render the structure in violation of the applicable non-elevation design requirements of this ordinance.
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New construction shall mean structures for which the start of construction commenced on or after the effective date of this ordinance and shall include any subsequent improvements to such structures. Non-substantial improvement shall mean any improvement that does not meet the definition of substantial improvement, as defined in this section. Qualified engineer shall mean a registered professional engineer who, by reason of training and experience, is considered knowledgeable in hydrology and hydraulics and their application to the flood insurance study. Special Flood Hazard Area shall mean the land in the floodplain subject to a one percent or greater chance of flooding in any given year. Start of construction shall mean either the first placement of permanent construction of a structure on a site, such as the pouring of slabs or footings, the installation of piles, the construction of columns, or any work beyond the stage of excavation, or the placement of a manufactured home on a foundation. Permanent construction does not include land preparation, such as clearing, grading, and filling; nor does it include the installation of streets and/or walkways; nor does it include excavation for a basement, footings, piers or foundations or the erection of temporary forms; nor does it include the installation on the property of accessory buildings, such as garages or sheds not occupied as dwelling units or not as part of the main structure. For a substantial improvement, the actual start of construction shall mean the first alteration of any wall, ceiling, floor, or other structural part of a building, whether or not that alteration affects the external dimension of the building. Structure shall mean, for floodplain management purposes, a walled and roofed building, including a gas or liquid storage tank that is principally above ground, as well as a manufactured home. Substantial damage shall mean damage of any origin sustained by a structure whereby the cost of restoring the structure to its before damaged condition would equal to or exceed fifty percent of the market value of the structure before the damage occurred. Substantial improvement shall mean any reconstruction, rehabilitation, addition, or other improvement of a structure, the cost of which equals or exceeds fifty percent of the market value of the structure before the start of construction of the improvement. Substantial improvement shall include structures which have incurred substantial damage, regardless of the actual repair work performed. The term shall not, however, include either (i) any project for improvement of a structure to correct existing violations of state or local health, sanitary, or safety code specifications which have been identified by the local code enforcement official and which are the minimum necessary to assure safe living conditions, or (ii) any alteration of a historic structure, provided that the alteration will not preclude the structure’s continued designation of a historic structure. Violation shall mean the failure of a structure or other development to be fully compliant with the floodplain management regulations as set forth in this chapter. A structure or other development without the elevation certificate, other certifications, or other evidence of compliance as required is presumed to be in violation until such time as that documentation is provided.
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Standards. The following shall be the standards to be followed in connection with the Flood Regulations for the Existing Urban Area of the town of Outapi: General Standards: (1) No development or substantial improvement shall be permitted within the floodway as designated by the Plan or as determined by hydrologic and hydraulic studies completed by the Town Council or other government agency, or other acceptable source as approved by the Town Council. (2) In those areas where a floodway has not been designated, no development or substantial improvement may be permitted within the floodplain or flood prone area unless the applicant has demonstrated that the proposed development or substantial improvement, when combined with all other existing and reasonably anticipated developments or substantial improvements, will not increase the water surface elevation. (3) Roadway bridges, and other drainage facilities, may have their superstructure submerged or partially submerged below the base flood level, provided that the facility has been designed to resist the hydrostatic and hydrodynamic loads as well as the effects of the buoyancy as certified by a registered professional engineer. (4) Within the floodplain or flood prone area, all new construction and substantial improvements shall be anchored to prevent flotation, collapse, or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads including the effects of buoyancy; constructed with materials and utility equipment resistant to flood damage; and constructed by methods and practices that minimize flood damage. Electrical, heating, ventilation, plumbing, and air conditioning equipment and other service facilities shall be elevated at least one foot above the base flood elevation or designed so as to prevent water from entering or accumulating within the components during conditions of flooding. A registered professional engineer or architect shall certify that these provisions are satisfied. (5) The location, grade, and flood proofing of all new and replacement water and sanitary sewer systems which are to be extended into or through any portion of the floodplain or flood prone area to serve the proposed development shall first be approved by the city prior to the extension of such utilities into the floodplain. (6) New or replacement water supply systems and sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into said systems and discharges from said systems into flood waters. (7) On-site waste disposal systems shall be located to avoid impairment to the system or contamination from such systems during flooding. (8) The storage or processing of materials which are in time of flooding buoyant, flammable, explosive, or could be injurious to human, animal, or plant life is prohibited. (9) Storage of other material or equipment may be allowed if not subject to major damage by floods and firmly anchored to prevent flotation or if readily removable from the area within the time available after the issuance of flood warning by appropriate authorities.
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(10) Filling, grading, and excavation may be allowed in the floodplain or flood prone area under the following conditions: (i) Fill shall be protected against erosion and sediment by such measures as rip-rap, vegetative cover, bulkheading, or sedimentation basins. (ii) Any fill to be deposited in the floodplain or flood prone area must be shown by the applicant not to be a detriment to the general public as well as the surrounding land owners. (iii) Fill materials shall be of a selected type, preferably clean dirt, gravel, or rock no greater than two inches in diameter. The use of decomposing materials, such as wood and other degradable shall be prohibited. Fill shall be placed in six inch compacted layers. Fill selection and placement shall recognize the effects of saturation from flood waters on slope stability, uniform and differential settlement, and scour potentials. (iv) Prior to placement of any fill or embankment materials, the land upon which fill is to be placed shall be cleared of debris, snags, stumps, brush, down timber, logs, and other objects. All materials and debris from this clearing shall be removed from the proposed fill and disposed of at approved locations outside the floodplain or flood prone area. (v) Fill slopes for granular materials shall be no steeper than one vertical on two horizontal unless substantiating data justifying steeper slopes are submitted to the Director of Building and Safety and approved. (vi) Excavation in the floodplain or flood prone area shall be done so that the land surface is maintained in such a manner that surface waters do not collect and pond. Residential Construction. All new construction and substantial improvements of residential structures within the floodplain or flood prone area shall have the lowest floor, including basement, elevated at least one foot above the base flood level. Garages and storage buildings used exclusively for the storage of motor vehicles, and storage of other items readily removable in the event of a flood warning may have their lowest floor below flood elevation, provided the building structure is capable of withstanding hydrostatic and hydrodynamic forces caused by the 100-year flood and, further, provided that no utilities are installed in the building except elevated or flood proofed electrical fixtures. If the building is converted to another use, it must be brought into full compliance with the requirements of this title governing such uses. Nonresidential Construction. All new construction and substantial improvements of commercial, industrial, and other nonresidential structures within the floodplain or flood prone area shall either have the lowest floor, including basement, elevated at least one foot above the base flood level or, together with attendant utility and sanitary facilities, be flood proofed so that below the base flood level plus one foot the structure is watertight in accordance with the performance standards set forth in the city's building code. A registered professional engineer or architect shall develop or review structural design, specifications, and plans for the construction, and shall certify that the design and methods of construction meet the watertight performance standards. For all new construction and substantial improvements, fully enclosed areas below the lowest floor that are usable solely for parking of vehicles, building access or storage in an area other than a basement and which are subject to flooding shall be designed to
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Northern Regions. Flood Risk Management Plan 2011 automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Floodways. ! Encroachments into the floodway are prohibited, including fill, new construction, substantial improvements, and other development within the floodway unless certification by a qualified engineer is provided, demonstrating that the proposed encroachment will not result in any increase in flood levels during occurrence of the base flood discharge along the floodway profile. ! An exception to the above shall be permitted provided the applicant has acquired by land rights purchase, flowage easement, or other legal arrangement the right to increase the flood levels on all affected lands. ! If the above provision is satisfied, all new construction and substantial improvements shall comply with all other applicable provisions. ! The placement of any home extensions and the construction of new structures for human habitation within the floodway are prohibited. Administration. A development permit shall be required in conformance with the provisions of this chapter. All new construction of residential and nonresidential structures or other development, including the placement of manufactured homes, within the floodplain or flood prone area shall hereafter be in full compliance with the terms of this chapter and other applicable regulations. All existing residential and nonresidential structures that are not in compliance with the terms of this chapter shall be required to conform to these terms before substantial improvements can be made. It shall be the duty of the Director of Planning to enforce this chapter. His duties shall include, but not be limited to: (a) Review all development permits to assure that the permit requirements for this chapter have been satisfied; (b) Review proposed development to assure that all necessary permits have been obtained from those agencies from which prior approval is required by national, regional or local law. (c) Notify affected adjacent communities prior to any alteration or relocation of a watercourse, and assure that the flood-carrying capacity within the altered or relocated portion of any watercourse is maintained; (d) Require a registered professional engineer or registered professional land surveyor to verify the actual elevation of the lowest floor, including basement, of all new or substantially improved structures and to which the new or substantially improved structures have been flood proofed. The certification of the lowest floor shall be submitted to the Director of Planning at the point of construction when the lowest floor elevation may be established and prior to the erection of the walls of any buildings. Such information shall be recorded and maintained by the Director of Planning; (e) Where flood proofing is utilized for a particular structure, obtain certification from a registered professional engineer or architect that the flood proofing methods are adequate in accordance with appropriate provisions of the Town Council’s regulations;
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(f) Where interpretation is needed as to the exact location of boundaries of the floodplain or flood prone area; for example, where there appears to be a conflict between a mapped boundary and actual field conditions, obtain the necessary interpretation from appropriate engineering staff of the Town Council; Permit Procedures. Application for a development permit shall be made to the Director of Planning on forms furnished by her/him and may include, but not be limited to, the plans drawn to scale showing the nature, location, dimensions, and elevations of the area in question, existing or proposed structures, fill, storage of materials, drainage facilities, and the location of the foregoing. Specifically, the following information is required: (a) Base flood elevation. (b) Elevation of the lowest floor, including basement, of all structures. (c) Elevation to which any nonresidential structure has been floodproofed. (d) Documentation and certification from a registered professional engineer or architect that the nonresidential floodproofed structure meets the required floodproofing specifications. (e) Documentation and certification from a registered professional engineer that if the development is in the floodway, that the development will cause no rise in the flood elevation. (f) Description of the extent to which any watercourse will be altered or relocated as a result of proposed development. (g) Limits of floodway and floodplain or flood prone area. (h) If the permit is for fill or the development of multiple structures, the following additional information is required to be shown on a grading and drainage plan: (1) A grading plan showing existing and proposed grades, location of channel and hydraulic cross- sections and profiles. (2) Hydrologic and hydraulic summary report. (3) The type and extent of the proposed use or development of the land which is located within the floodplain or flood prone area, along with such information as is necessary to determine the effect flood waters will have on such development and use and the effect such development and use may have upon the flood waters. All such information shall show the location of the proposed use, areas of habitation and employment, including the location, size, and floor elevation of any structures, the location and elevation of all parking areas, and the use, location, and elevations of all open land areas. (4) The amount of fill material brought into the floodplain or flood prone area from outside the floodplain or flood prone area. Permit Expiration. Every floodplain permit shall expire and become null and void two years following the date of issuance, regardless of the status of the permitted work. Before such work can be recommenced, a new permit shall be first obtained to do so. Any authorized investor holding an unexpired permit may apply for an extension of the time within which work must be completed. The Director of Planning may extend the time for
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Northern Regions. Flood Risk Management Plan 2011 completion of the work for a period not exceeding one year upon the authorized investor showing that circumstances beyond the control of the authorized investor have prevented action from being taken to complete the work. No permit shall be extended more than once. Any permit issued prior to the effective date of this Flood Regulations shall expire and become null and void two years following the effective date of this ordinance, regardless of the status of the permitted work, and may not be extended by the Director of Planning. Before such work can be recommenced, a new permit shall be first obtained to do so. Special Permits. The Outapi Town Council may, by special permit: (a) Grant variances from the requirements of this chapter which permit construction in a manner otherwise prohibited by this chapter where specific enforcement would result in unnecessary hardship. However, variances shall not be issued by the city within the selected floodway if any increase in flood levels during the base flood discharge would result. (b) Grant requests for substantial improvements of existing residential and nonresidential structures that are not in conformity with the provisions of this chapter. (c) Attach certain conditions to the special permit as it deems necessary to further the purposes of this chapter. In passing upon such special permits, the Town Council shall consider that permits shall only be issued upon a determination that (i) they are the minimum necessary, considering the flood hazard, to afford relief; (ii) the granting will not result in increased flood heights, additional threats to public safety, extraordinary public expenses, create nuisances, cause fraud on or victimization of the public, or conflict with existing local laws or ordinances; and (iii) the decision is based upon a showing of good and sufficient cause and a reasonable use of land involved. Any applicant to whom a special permit is granted shall be given a written notice that the cost of flood insurance will be commensurate with the increased risk resulting from the reduced lowest floor elevation. The Director of Planning shall maintain all the records of special permits issued by the Town Council. Pre-existing Uses. The following pre-existing uses will be allowed in the floodplain: (a) Continuation of pre-existing uses. The lawful use of a building and premises existing prior to the effective date of this Flood Regulations may be continued although such use does not conform to the provisions hereof; provided, that no expansion, enlargement, change, or alteration shall be made. (b) Substantial improvements of preexisting uses. No existing building and premises which is not in conformity with the provisions of this chapter shall be substantially improved unless it is done in conformity with the provisions of this chapter. A request for the substantial improvement of a pre- existing use which does not conform to the provisions of this chapter shall be processed through special permit procedures. Penalties for Violation. Violation of the provisions of this chapter or failure to comply with any of its requirements shall be punished in accordance with existing procedures.
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ACTION PLAN FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 369 Northern Regions. Flood Risk Management Plan 2011
9.0- FLOOD RISK MANAGEMENT PLAN. ACTION PLAN.
Activities Actions Description Stakeholders Date Detailed study on major hydraulic solutions for the whole Cuvelai basin, including southern Angola Basin Management Committee, Regional Councils, Ministry of 0101 Preparation of Terms of Reference TBD Environment, Ministry of 01 Agriculture, Water and Forestry Appointment of Consultant to carry out the 0102 MRLGHRD TBD assessment 0103 Preparation of Assessment Consultant TBD Other planning studies MRLGHRD, Regional Councils, Town Councils, 0201 Preparation of Terms of Reference Ministry of Agriculture, TBD 02 Water and Forestry, Roads Authority Appointment of Consultant to carry out the planning 0202 MRLGHRD TBD studies 0203 Preparation of planning studies Consultant TBD Environmental Impact Assessment MRLGHRD, Regional Councils, Ministry of Environment, 0301 Preparation of Terms of Reference Ministry of Agriculture, TBD 03 Water and Forestry, NAMWATER, Roads Authority Appointment of Consultant to carry out the MRLGHRD , Regional 0302 TBD assessment Councils 0303 Preparation of Environmental Impact Assessment Consultant TBD New developments in higher lands Identification of new areas located in higher grounds suitable for the relocation of population residing in flood prone areas, considering two options: 0401 Regional Councils TBD 1. Extension of existing settlement areas, and 2. Creation of new settlements. TBD 0402 Tendering (design) Regional Councils For the existing settlement areas: - Surveying of the land allocated for the relocation of population residing in flood prone areas. - Detailed design of the proposed TBD extensions: new residential areas, Regional Councils including necessary services. 04 - Improvement of existing general services: water supply, sanitation, electricity, sewerage system, including upgrading of oxidation ponds. For the new settlements; - Surveying of the land allocated for the relocation of population residing in flood TBD 0403 prone areas. Regional Councils - Detailed design of the proposed extensions: new residential areas, including necessary services. Detailed design of the proposed extensions: new TBD 0404 Consultant residential areas, including necessary services Improvement of services (water supply, sanitation, electricity, sewerage system, including upgrading of TBD 0405 Regional Councils existing oxidation ponds) in the existing selected settlements.
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TBD 0406 Tendering (construction activities) Regional Councils TBD 0407 Construction of necessary services Consultant
Relocation of vulnerable population Verification of exact number of population residing in TBD 0501 Regional Councils flood prone areas that need to be relocated Identification of the prioritized areas, to establish a TBD 05 0502 Regional Councils phased relocation process. Phased relocation of vulnerable population to the TBD 0503 new areas once necessary services are constructed Regional Councils by stages Compensation of traditional houses Create awareness among land owners about the importance to transfer land ownership to local Regional Councils, TBD 0601 authorities in order to relocate population living in Traditional Leaders. flood prone areas 06 TBD 0602 Land valuation Ministry of Lands
Regional Councils, TBD 0603 Actual compensation Traditional Leaders, Ministry of Lands Improvement of natural water ways Regional Councils, Ministry of Environment, TBD 0701 Consultation with stakeholders Ministry of Agriculture, NAMWATER, Roads Authority Appointment of Consultant to carry out the TBD 0702 Regional Councils preparation of the required project. Tendering. 07 Preparation of project, considering all necessary TBD 0703 activities (deepening of rivers, removal of existing Consultant (design) obstructions, improvement of local drainage) TBD 0704 Tendering (construction activities) Regional Councils Project implementation – construction activities: Deepening of rivers. Removal of structures, debris, TBD 0705 Consultant (construction) garbage and vegetation. Improvement of local drainage within selected towns and settlements. Construction of small hydraulic works Technical debate on solutions for the proper design Regional Councils, TBD 0801 of small hydraulic works in the affected areas MRLGHRD TBD 0802 Tendering (design) Regional Councils
08 Preparation of projects of selected roads and TBD 0803 Consultant bridges TBD 0804 Tendering (construction) Regional Councils TBD 0805 Construction activities (roads and bridges) Consultant (construction)
Development of small scale tolerable agricultural activities Identification of small scale tolerable agricultural Ministry of Agriculture, 09 0901 activities, according to specific existing conditions in Water and Forestry. TBD each of the affected regions Regional Councils Rehabilitation of most affected roads and bridges Technical debate on solutions for the proper design Regional Councils, Roads TBD 1001 of most affected roads and bridges within the area Authority, MRLGHRD covered by the Cuvelai basin TBD 10 1002 Tendering (design) Regional Councils Preparation of projects of selected roads and TBD 1003 Consultant bridges TBD 1004 Tendering (construction) Regional Councils
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TBD 1005 Construction activities (roads and bridges) Consultant (construction)
Rehabilitation of most affected sewerage systems Technical debate on solutions for the proper design Regional Councils, TBD 1101 of most affected sewerage systems within the whole MRLGHRD affected area. TBD 1102 Tendering (design) Regional Councils
11 Preparation of projects of selected roads and TBD 1103 Consultant bridges TBD 1104 Tendering (construction) Regional Councils TBD 1105 Construction activities (roads and bridges) Consultant (construction)
Improve community participation in disaster management Identification of communities to be incorporated Regional Councils, TBD 1201 within the specific studies Traditional Leaders Appointment of Consultant to carry out the TBD 1202 Regional Councils 12 assignment TBD 1203 Preparation of assignment Consultant
Implementation of the assignment in selected TBD 1204 Consultant communities
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FINAL CONCLUSIONS FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 373 Northern Regions. Flood Risk Management Plan 2011
10.0- GENERAL CONCLUSIONS The main objectives of the study were accomplished since it was possible to obtain a general overview of the existing situation in the affected areas, from the territorial, regional and urban levels, identifying the main causes behind the damages, recommending the regional and town councils a group of general and specific actions to mitigate the flood impact on rural and urban areas. The problem of floods in northern Namibia is in part originated outside the national territory and constitutes an issue of ample magnitude that cannot be approached from a local perspective, even though, local actions can indeed be undertaken. Man-related actions are a principal cause of flood risks and damages, mainly in urban sites where infrastructure and buildings are frequently wrong allocated in low-lying flood-prone areas or standing in the natural waterways. The present study is only a preliminary one and intends to serve only as an initial step in the path of appropriate and definitive solutions that will necessary require further studies and projects.
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BIBLIOGRAPHY FLOOD RISK MANAGEMENT PLAN Prepared by: Architect Carlos V. Tamayo, Geographer Félix D. Hernández, Geographer Armando C. Muñiz , Architect Abel Gil Page 375 Northern Regions. Flood Risk Management Plan 2011
11.0 – BIBLIOGRAPHY 1. - Report on National Response to the 2008 Flood Disasters. Compiled by the Office of the Prime Minister, September 2008. 2. - Report on the 2009 Flood Disaster Response, July 13, 2009. Office of the Prime Minister: Directorate Disasters Management. 3. – National Policy for Disaster Risk Management in Namibia. Office of the Prime Minister. Directorate Disasters Risk Management. 4. – National Atlas of South West Africa (Namibia). Editor: J. H. Van der Merwe; editorial committee: Institute for Cartographic Analysis, University of Stellenbosch. I. J. van der Merwe, J.H. van der Merwe and Directorate Development Co-ordination, SWA; g. j. f. Gous, ; H. Fourie; J. de Kock. Printed and bound by Narional Book Printers Goodwood, Cape, 1983. Reproduction by Unidfito, Cape Town / ISBN 0 7972 0020 7. 5. – Regional Poverty Profile. Summary Report. Caprivi Region. 6. - Regional Poverty Profile. Summary Report. Kavango Region. 7. - Regional Poverty Profile. Summary Report. Omusati Region. 8. - Regional Poverty Profile. Summary Report. Ohangwena Region. 9. – 2001 Population and Housing Census. Caprivi Region. Central Bureau of Statistics. National Planning Commission, November 2004. 10. - 2001 Population and Housing Census. Kavango Region. Central Bureau of Statistics. National Planning Commission, November 2004. 11. - 2001 Population and Housing Census. Oshana Region. Central Bureau of Statistics. National Planning Commission, November 2004. 12. - 2001 Population and Housing Census. Omusati Region. Central Bureau of Statistics. National Planning Commission, November 2004. 13. - 2001 Population and Housing Census. Ohangwena Region. Central Bureau of Statistics. National Planning Commission, November 2004. 14. – Population projections. 2001 – 2031. Central Bureau of Statistics. National Planning Commission, January, 2006. 15. – Early Recovery Strategic. Framework. For the Disasters Prone areas of Namibia, August, 2009. 16. – Namibia. Crop Prospects and Food Security Situation Report, July 9, 2009. 17. – Annual livelihoods vulnerability forecast for North, West, Central and Eastern Namibia, Report, July, 2009. 18. – Project: Oshakati a Concept of Beauty. Oshakati Concept Master Plan. July 2009. Prepared by BAR 19.- Postgraduate Course on “Environmental Impact Assessment in Projects” sponsored by Cordova University, Spain; University College “Jose Marti” ; and the National Bureau of Architects and Engineer of Construction of Cuba (UNAICC), in Sancti Spirits province, Cuba. February/2007. 20.- Report on flood impact on the six most affected regions of the northern part of the republic of Namibia. Prepared by Cuban experts of the Institute of Physical Planning for the Ministry of Local and Regional Government, Housing and Rural Development. September-December, 2009.
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