Water Resources Assess ment

for

Biguli Sub-County, District.

FINAL REPORT

VOLUME I WATER RESOURCES ASSESSMENT REPORT

Prepared and Submitted By FELS CONSULTANTS LTD

Plot 4 Kira Road Kamwokya April 2017

Vol. I – Water Resources Water Resources Assessment of Biguli Sub County in Assessment Report

Table of Contents EXECUTIVE SUMMARY ...... 1 1.0 INTRODUCTION ...... 4 1.1 Preamble ...... 4 1.2 General Background ...... 4 1.3 Purpose of the Assignment: ...... 5 1.4 Key Objectives: ...... 5 1.5 Government Policies ...... 5 2.0 PROJECT AREA ...... 7 2.1 Location ...... 7 2.2 Administrative Units ...... 8 3.0 LITERTARATURE REVIEW ...... 9 3.1 Socio-Economic situation of the study area ...... 9 3.1.1 Demographics ...... 9 3.1.2 Land use ...... 9 3.1.3 Economic activities ...... 9 3.1.4 Settlement pattern ...... 10 3.1.5 Occupation ...... 10 3.2 Characteristics of the Climate in the Study Area ...... 10 3.3 Biophysical data of the study area ...... 12 3.3.1 Topography ...... 12 3.3.2 Geology ...... 12 3.3.3 Soils...... 13 3.3.4 Vegetation ...... 13 3.4 Surface water status of the study area ...... 13 3.4.1 Drainage ...... 13 3.4.2 Annual Rainfall and Monthly Variations ...... 14 3.4.3 Comparison of the Old data and Recent Satellite Data ...... 16 3.5 Groundwater Status of Kamwenge ...... 17 4.0 APPROACH, METHODOLOGY AND WORK DONE ...... 19 4.1 Approach and Methodology ...... 19 4.2 Work Done ...... 21

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4.2.1 Environment and Social Consideration Survey ...... 22 4.2.2 Groundwater surveys – siting of production boreholes ...... 22 4.2.3 Surface water surveys perennial streams and rivers visited...... 22 5.0 RESULTS AND INTERPRETATION ...... 24 5.1 Socio-Economic Survey ...... 24 5.1.1 Agriculture ...... 24 5.1.2 Commercial farming ...... 24 5.1.3 Sanitation and hygiene ...... 24 5.1.4 Sampled villages...... 25 5.1.5 Readiness to receive water ...... 26 5.1.6 Willingness to pay for the water and the Cost of water ...... 26 5.2 Surface Water Resources ...... 27 5.2.1 Catchment Yield ...... 27 5.2.2 Catchment delineation ...... 30 5.2.3 Exploitable surface water resources ...... 31 5.2.4 Development of Surface Water Resources ...... 32 5.2.4 Key conclusions and recommendations on the surface water resources ...... 32 5.3 Groundwater resources ...... 33 5.3.1 Identification of Potential Locations for drilling of production wells ...... 33 5.3.2 Groundwater data ...... 35 5.3.3 Spatial variation of First Water strike and Main water strike ...... 36 5.3.4 Spatial variation of depth to bedrock and airlift yield ...... 37 5.3.5 Hydro-Geostatistical Analysis ...... 38 5.3.6 Assessing the Water Quantity (Test Pumping) ...... 39 5.3.7 Groundwater Quality ...... 40 5.3.8 The groundwater resources of the study area ...... 43 5.3.4 Key conclusions and recommendations on the groundwater resources ...... 45 5.4 Total Available Water Resources ...... 46 6.0 CHALLENGES ...... 47 6.1 Project Duration...... 47 6.2 Existing Data ...... 47 7.0 CONCLUSION ...... 48 7.1 Literature Review ...... 48 7.2 Socio-Economic Survey ...... 48

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7.3 Hydrogeological Survey ...... 48 7.4 Surface Water Survey ...... 49

List of Tables

Table 2.1.: Administrative units in Kamwenge District ...... 8

Table 2.2.: Administrative units in Biguli Sub-County ...... 8

Table 3.1.: The project Sub-County demographics...... 9

Table 3.2.: Hydro-climatic variation in the study area ...... 11

Table 3.3.: Location of the old rainfall stations in the vicinity of the study area ...... 14

Table 3.4.: Mean annual precipitation for the stations in the vicinity of Biguli S/C. 16

Table 3.5.: Descriptive hydrogeological parameters of Kamwenge District ...... 17

Table 4.1.: Input data and the method used in the processing/generation of the map. . 20

Table 4.2.: Reports that were collected and reviewed during the study ...... 21

Table 5.1.: Estimate annual rainfall amount and volumes for each catchment ...... 31

Table 5.2.: The computed surface water flow in the six catchments of the study area.. 31

Table 5.3.: Villages where detailed borehole site surveys were conducted ...... 34

Table 5.4.: Villages identified for drilling and the expected detailed drilling parameter . 35

Table 5.5.: Descriptive geo-statistical analyses for the existing hydrogeological data .. 38

Table 5.6.: Log plots of test pumping results used to characterise the aquifers...... 39

Table 5.7.: The computed groundwater recharge volume ...... 43

Table 5.8.: The total available water resources in the study area ...... 46

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Vol. I – Water Resources Water Resources Assessment of Biguli Sub County in Kamwenge District Assessment Report

List of Figures

Figure: 2.1.: Biguli Sub-County in Kamwenge District...... 7

Figure: 2.2.: ’s WMZs and 8 river basins (CMP-guideline 2014) ...... 7

Figure 3.1a.: Climatic zoning of the Uganda – DWRM study ...... 11

Figure 3.1b.: Location of the Historical rain gauge stations close to the study area...... 11

Figure 3.2.: Average rainfall distribution patterns over the two climatic zones ...... 12

Figure 3.3.: Geological map of Biguli Sub-County ...... 13

Figure 3.4a.: Drainage map of Kamwenge District ...... 14

Figure 3.4b.: Drainage map of Biguli Sub county ...... 14

Figure 3.5.: Mean monthly rainfall for the stations representing the study area ...... 15

Figure 3.5.: Aerial distribution of rainfall across Biguli sub county ...... 15

Figure 3.6.: Comparison of Old data and satellite data ...... 16

Figure 3.10.: Groundwater quality for Kamwenge district...... 18

Figure 3.11.: Groundwater potential for Kamwenge district...... 18

Figure 4.1.: Existing surface water resources ...... 23

Figure 5.1.: Commonly grown crops in Biguli S/C...... 24

Figure 5.2.: Presence of an Excreta Disposal Facility, EDF, in the project area ...... 25

Figure 5.3.: Sampled areas for social survey ...... 26

Figure 5.4.: Preferred sources of water at Household...... 26

Figure 5.5.: Simulated and observed discharge time series for R. Katonga ...... 27

Figure 5.6.: Water balance for the calibrated model ...... 28

Figure 5.7.: Potential flow volumes likely to be generated from Biguli Sub-County ...... 28

Figure 5.8.: Biguli yield variation curve against probability of exceedance ...... 29

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Figure 5.9.: Daily Peak flow volumes from Biguli against return periods ...... 29

Figure 5.10.: Daily low flow volumes from Biguli against return periods ...... 30

Figure 5.11.: Delineated micro catchments for Biguli sub county...... 30

Figure 5.12: Proposed potential location of Water for Production facilities...... 32

Figure 5.13: Simple rain gauge station and flow monitoring station (gauge)...... 33

Figure 5.14.: Sample results of the geophysical survey results – Line profiling ...... 33

Figure 5.15.: Sample results of the geophysical survey – VES sounding ...... 34

Figure 5.16.: Data density for the interpolated maps presented in this chapter ...... 35

Figure 5.17.: Variation of First and Main Water Strikes in Biguli S/C...... 36

Figure 5.18.: Variation of depth to bedrock with total estimated yield in Biguli S/C...... 37

Figure 5.19: Variation of water strike with bedrock depth ...... 39

Figure 5.20a.: Concentration plot of the major anions ...... 41

Figure 5.20b.: Concentration plot of the major cations ...... 41

Figure 5.21.: Variation of E Coli on sampled water sources in Biguli sub county ...... 42

Figure 5.22.: Groundwater flow direction in the study area ...... 43

Figure 5.23.: Schematised groundwater occurrence model in the study area ...... 44

Figure 5.24.: Aquifer systems of the study area ...... 45

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Vol. I – Water Resources Water Resources Assessment of Biguli Sub County in Kamwenge District Assessment Report

EXECUTIVE SUMMARY

As part of their efforts of implementing the Water for All in Biguli Sub County of Kamwenge District, Water For People commissioned a water resources assessment study in Biguli Sub county under the background of working together with Government (Local and Central) in fast-tracking the attainment of the SDG’s through addressing the challenges of water availability. In so doing, a socio-economic survey, surface water study and groundwater study was conducted in Biguli Sub County especially in the four parishes of Kabuye, Biguli, B and Malere.

This report contains two volumes; Volume l is the water resources assessment report (surface and groundwater with a socio-economic aspect in terms of sanitation and hygiene as well as project appreciation) and Volume ll is the stakeholder engagement report which identifies the threats faced by the subcounty at a micro-catchment level and how they can be managed.

Volume l: Water Resources Assessment Report.

Socio-Economic Aspect With an estimated population of nearly 34,100 persons (49% female), the literacy rate in the study districts is as low as 12%. Settlements are scanty with concentrations around productive agricultural areas that are rain-fed, trading centres and near rivers banks and springs. Culturally, domestic chores are mainly bestowed on women and children with men providing limited support.

Whereas the safe water coverage is as low as 25%, the source functionality across the study area is 89%. The communities are willing to pay for a proper, functional and reliable water supply system

There is high latrine coverage at household levels and even at institutional levels, some schools and health centres do not have proper sanitary facilities. The practise of hand washing is predominantly low.

Surface Water Resource Rainfall within the study area increases in a southeast – northwest trend ranging from 950mm – minimum to 1175mm – maximum. The area has two rainfall seasons and two dry seasons. There are few streams that flow even during the dry seasons especially in southern reach of the study area. Most of the mapped water bodies are filled with “marsh-like” vegetation.

The Mike NAM “Nedbør Afløbs Model” an extension of MIKE 11 developed by DHI was used to build a rainfall - runoff model. The model was built and calibrated based on the gauged river flows of River Katonga and was then used to generate flow time series for Biguli subcounty as a catchment. Therefore the available surface water resources annually is 178.8 x 106 cubic meters Biguli subcounty and the available exploitable surface water resources is (at 80% exceedance) 143,663 m3/year. Based on the exceedance values, it can be seen that even during dry years (probability of exceedance ≥80), there are significant volumes of water that can be generated from the Biguli as a catchment.

The potential for harvesting the large amount of runoff (through dams and valley tanks) generated in the upstream parts of the study area is high. The harvested surface water can be used to start plantation agriculture and improve the livelihood of the people living in the area.

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Groundwater Resource Geologically the study area has large contracts in geology ranging from loose alluvial material, meta-igneous rocks and intrusive. The geophysical investigations showed the need to employ line profiling while selecting sites for drilling. The anticipated water strikes are both in the regolith and fissured zones.

Because well construction in the region taps water from both the regolith and fractured rock, a categorisation of the test pumping results yielded three distinct patterns of varying behaviour with increased pumping durations as observed from the log-log plots of drawdown wit time. The results further show that in addition to having localised aquifers, there is limited interconnection.

Water quality test results showed the water to be fresh and of Bi-carbonate type. Physio- chemically the water is of good and acceptable quality however, contamination resulting from human activity is prevalent. The situation is gets worse during the rainy season.

In the study area, Occurrence of groundwater is mainly limited to the upper weathered section and the transition–to-bedrock zones of the basement rock. Most drilling records have pointed to the main aquifers in this zone however; deeper drilling to depths greater than 80m in the region is rare.

A simple groundwater flow model was developed. The model showed the overall flow to be in north-south direction however, at a small scale, areas of groundwater concentration (groundwater “sink-holes”) were mapped. With careful investigations, these locations could provide reliable amounts of safewater for large scale abstraction.

Volume ll: Stakeholder Engagement Report.

The 2005 Water Sector Reform Study and the 2006 Joint Sector Review (JSR) both recommended the implementation of IWRM at the catchment level. The National Water Policy provides an overall policy framework and defines the Government’s policy objective as: “To manage and develop the water resources of Uganda in an integrated and sustainable manner, so as to secure and provide water of adequate quantity and quality for all social and economic needs of the present and future generations and with the full participation of all stakeholders”.

The project subcounty was there delineated into 6 micro-catchments namely; Kabaga, Karawhire, Kizikibi, Nayinguru, Rwakasirabo and Upper Kabaga, in order to identify the threats of these micro catchments with the participation of various stakeholders.

The discussions with the various stakeholders at Kamwenge District, Biguli subcounty and the villages within showed that there were mainly four areas of concern that were threatening their subcounty micro catchments. These include social welfare, water resources, environment and public health. The threats were assessed using a matrix method and the main challenge was environmental aspect/concerns.

Based on the national guidelines for the development of a catchment management plan, the study has identified and proposed key activities that may be undertaken at a rather small scale level but will have a big impact on the hydrology of the entire study area. Some of these activities include

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Vol. I – Water Resources Water Resources Assessment of Biguli Sub County in Kamwenge District Assessment Report reforestation, protection of the buffer zones of the water bodies, harvesting of not only the rainfall but the runoff generated in the upstream parts of the study area as well.

The above study results provide vast opportunities to undertake development interventions towards the improvement of the quality of life of the people in Biguli Sub County which may be undertaken by several stakeholders including government. It may of much benefit if the findings of this report are shared with potential development partners.

Note: Some maps within the reports may not be clear but A3 maps have of the same have been appended at the end of each volume.

LIST OF ABBREVIATIONS AND ACRONYMS

DTM - Digital Terrain Model DWD - Directorate of Water Development. DWO - District Water Officer(s) DWRM - Directorate of Water Resources Management. DWO - District Water Office(er). EC - Electric Conductivity GV - Guideline Value H/C - Health Centre HPMA - Hand Pump Mechanics Association HH - House Hold MAV - Maximum Allowed Value MWE - Ministry of Water and Environment NGO - Non Governmental Organisation NGWDB - National Groundwater Data Base. S/C - Sub County std - Standard Deviation ToR - Terms of Reference TSU - Technical Support Unit WASH - Water Sanitation and Hygiene WATSAN - Water and Sanitation WATSUP - Water Atlas Update WfP - Water for Production

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Vol. I – Water Resources Water Resources Assessment of Biguli Sub County in Kamwenge District Assessment Report

1.1 INTRODUCTION

1.2 Preamble Fresh water is a key strategic resource in Uganda and a driver to her economic development. Although Uganda is considered as being well endowed with water resources, the country is experiencing water management issues relating to variability in both space and time (seasonality), increasing water demand. The spatial and seasonal variability of water resources in Uganda raises concern in the context of the;

▪ Rapid population growth, ▪ Increased need for water for human use, agricultural production and livestock, ▪ Challenges posed by the recent phenomenon of Climate change.

As a country, Uganda boasts of abundant water resources including rivers, fresh water lakes, and groundwater. For better water resources management and supporting districts to effectively manage the water resources, the country has been demarcated into 4 Water Management Zones; Victoria Water Management Zone, Kyoga Water Management Zone, Albert Water Management Zone and Upper Nile Water Management Zone. In each of the management zones there are main catchments and sub - catchments that have been delineated to properly utilize and manage the water resources in a sustainable manner.

1.3 General Background Responding to the increasing demand for water, this has seen the water supply sector undergoing rapid expansion with respect to rural and urban water supply and water for production. Small- scale irrigation is being promoted and will be of increased importance in the plan for modernization of Agriculture.

The need for a study of the available water resources, (surface water and groundwater), the environment, the behaviour of the people towards sustainable management of the available water resources and the need to utilise and manage the resource equitably within the Sub county of Biguli – Kamwenge District with a holistic approach to water resources to satisfy the sometimes- conflicting demands while ensuring rational water resources development for sustainable socio- economic development and poverty reduction as a whole cannot be over emphasised. It is upon this background that FELS Consultants was contracted by Water for People to carry out a water resources study for Biguli Sub County in Kamwenge district, western Uganda.

The catchment management plan (host to a greater part of Kamwenge District) stipulates issues and responsive water management interventions for each of the districts. However, it lacks the delineation of micro catchments at the sub county levels especially in the new sub-counties. This therefore means that water management and abstraction interventions cannot be effectively planned in these sub counties unless thorough ground and surface water resources mapping and assessment has been done to establish the existing status of the water resources in these areas. This status would inform the development of micro catchment plan which would feed into the bigger Mpanga Catchment Management plan.

The project sub county – Biguli Sub County is one of the new sub counties where Water for People is developing its groundwater systems however its micro catchments are not delineated on the Mpanga Catchment map and little is known about the flow rates and threats. This has called for the need to delineate the catchments as well as assess the catchments status in terms of water

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Vol. I – Water Resources Water Resources Assessment of Biguli Sub County in Kamwenge District Assessment Report quantity, quality, socio-economic and environmental aspects, threats and risks etc to inform its implementation of Local Water Resources Management interventions.

1.4 Purpose of the Assignment: The purpose of this project therefore, was to conduct a detailed Water resources assessment (ground and surface water) for Biguli Sub County that will be used by Water For People (W4P) and partners in planning for water supply system development and come up with very practical interventions at the very local scale that allow and ensure total community participation and ownership.

1.5 Key Objectives: The key objectives of this assignment are; 1) To assess and establish the ground water potential for Biguli sub county that can inform siting of production wells and other water supply systems.

2) To assess and ascertain the status of surface water resources in the sub county with much attention given to the micro catchments in the sub county. This will involve but not limited to nature of human activities around the catchments, extent of degradation and nature of land ownership

From the understanding of the scope of services and the study objectives, the deliverables of the assignment have been filtered to include mainly (but not limited to);

1. Conduct an in-depth study of the existing data and literature available for Kamwenge and particularly Biguli Sub-County regarding its hydro-geological conditions.

2. Carrying out a socio-economic baseline survey in all parishes of Biguli Sub County through field visits and interviews to determine community readiness for water supply including; willingness and affordability of water services.

3. Conduct a hydrogeological survey including determining; groundwater potential; flow rate, existence of fractures or faults, confined/unconfined/leaky aquifers, alluvial aquifers, typical potential formations/rocks, geological unconformity, potential geological structures among others. And make recommendations and a list of possible sites for production wells for piped water systems in the unserved areas as well.

4. Conduct surface water survey and mapping including; water shed and buffer area characteristics; land use cover, type and size of aquifers threats to the water source, existing and proposed water source protection measures.

5. Disseminate information on study to key stakeholders in the WMZ, partners and local authorities across the levels of governance.

1.6 Government Policies In response to the above challenges, Uganda developed water resources Action Plan in 1993- 1994 that laid down the basic principles and actions for a long-term sector reform. Subsequently,

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Vol. I – Water Resources Water Resources Assessment of Biguli Sub County in Kamwenge District Assessment Report the National Water Policy (1999), the Water Act (2000) and the associated Regulations for Water Resources (1998) and waste Discharge (1998) were all developed and have been operationalised.

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Vol. I – Water Resources Water Resources Assessment of Biguli Sub County in Kamwenge District Assessment Report

2.1 PROJECT AREA

2.2 Location Kamwenge district, in which W4P is implementing the “Water for Everyone for Forever” Program, is located in mid-western Uganda and a greater part of it located in the Albert Water Management Zone. The project Sub-County however is located in the Victoria Water Management Zone as shown in the figure below.

Figure: 2.1.: Biguli Sub-County in Kamwenge District.

Figure: 2.2.: Uganda’s WMZs and 8 river basins (CMP-guideline 2014)

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2.3 Administrative Units The district is composed of 2 counties and 16 Sub-Counties and 1 town council. The distribution of the Sub-Counties per County is shown in table 2.1 below.

Table 2.1.: Administrative units in Kamwenge District

County Sub-County Remark Kibale Busiriba Bwizi Kabambiro Kamwenge Kamwenge TC Biguli Project Area Rwamwanja R/S Kitagwenda Kanara Nkoma Ntara Buhanda Nyabbani Mahyoro Kicheche

Table 2.2.: Administrative units in Biguli Sub-County

Number Parish Village 1 Biguli Biguli, Bitojo, Buhumuriro, Businye, Byantumo, Kaishunga, Kirinda, Nyarubare, Rwebishasha and Kabaare

2 Malere Benga B, Benga Central, butamba, Butanda, Kagorora A, Kagorora B, Kanyegaramire, Lyakatama, Malere, and Nyakabungo

3 Kampala B Bweranyangi, Ibuga, Kakindo, Kampala, Kanyomyo, Karokarungi, Rwakasirabo, Soweto, Munyuma, and Nyakatooma 4 Kabuye Bisayumbe, Bubaree, Kaagati, , Kabuye, kagasha, Mukukuru, Muragi A, Muragi B, Mutama, and Nyakatookye

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3.1 LITERTARATURE REVIEW Information on social economic aspects and water resources, that was accessible, was reviewed and is presented below.

3.2 Socio-Economic situation of the study area This section of the report briefly highlights the factors that allow families to sustain themselves materially and socially including a mention of their main economic activities

3.2.1 Demographics The predominant ethnic groups in the District are Batagwenda, Batoro. However, there are a sizable number of Bakiga who have settled in the District. The languages spoken include mainly Rutooro, Rukiga and Rutagwenda. Biguli Sub County which is the project sub county has 4 parishes; Biguli, Kabuye, Kampala B and Malere. It is located in and has a total population of 34,367 (UBOS 2014), the sub county has an average population density of 217 persons/km2. The predominant language in the project sub county is Rutooro.

Table 3.1.: The project Sub-County demographics. 1 2 3 Parish No. of Villages Population Area Population Density Kabuye 10 5,823 23.84 244 Malere 10 7,717 29.92 258 Kampala B 10 7,903 37.98 208 Biguli 10 15,665 76.21 206

3.2.2 Land use Land in Kamwenge district is predominantly used for agriculture both animal husbandry and crop husbandry. The highlands of Kitagwenda county especially Kicheche sub county are used for coffee and millet growing while bananas grow on slopes and lowlands including other food crops like beans,maize,cassava,ground nuts and rice in the lift valley and livestock. The rest of the land is under agri-forestry establishments for the middle income earners and general human settlements like schools and rural growth centres.

On the other side of Kibale county land is used for the production of maize which is both food and cash crop for over 80% of the households and similar food crops as in Kitagwenda County. The coming of Congolese refugees affected cattle keepers in the area as they were displaced and had to relocate to other places within and outside the district. Land in the refuge settlement is now used for agricultural production especially maize, beans and Irish potatoes; the area has become business centre attracting traders from the whole country. (Kamwenge DDP)

3.2.3 Economic activities Agriculture and commercial farming Agriculture is the mainstay of the district economy. In the project area the communities practice agriculture in various forms including the growing of crops (food crops and cash crops) and the

1 Source - Water for People Database 2 Source - Water for People Database 3 Source – ArcGIS data from the Forestry Department

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Vol. I – Water Resources Water Resources Assessment of Biguli Sub County in Kamwenge District Assessment Report rearing of livestock. The main crops grown include sorghum, maize, millet, Matooke, peas, groundnuts, sunflower, sweet potatoes, beans, tea, coffee, cotton, tomatoes, cabbage, onions and pineapples. Banana farming is the main commercial crop in the project area.

3.2.4 Settlement pattern Just like the rural parts of Western Uganda, the human settlement is mainly along the road sides of the main roads and the feeder roads. In the built up centers, the houses are built of brick and sand with iron sheet roofs while the ones in the rural areas are built with some mud but roofed with iron sheets. This too is an indicator of improved income levels.

3.2.5 Occupation Agriculture including the growing of crops and the rearing of livestock forms the main and traditional mode of employment in the district (DDP 2015) however, the southern and southwestern parts of the districts, fishing and tourism sectors employs a section of the population living in the vicinity of the large water bodies ) and the National parks and game reserves. Since the district is host to a number of protected areas including, Kibaale National Park, , Katonga River, Lake George, , Queen Elizabeth National Park, River Mpanga, River Rushango, Tourism is a major activity. Farming is the main source of employment in the project area of Biguli Sub County. Other forms of employment include charcoal burning and mining of sand and stone quarrying.

3.3 Characteristics of the Climate in the Study Area. The climatic conditions in Kamwenge have been described based on a Hydroclimatic study undertaken by DWRM in 2007 (DWRM, 2007, unpublished report). The study was based on 14 climatological zones defined by Basalirwa et al (1993) using an analysis of monthly rainfall records at 102 rain gauges for the period 1940 - 75. The DWRM study subdivided three zones (C, M and A) to give a total of 17 climatological zones, as shown on Figure 3.1.

Kamwenge lies largely in Climatological Zone MW for which an average annual rainfall of 1,223 mm has been estimated. The rainfall shows a bi-modal distribution with two distinct rainy seasons, as shown on Error! Reference source not found.3.2. The main rainy season lasts from August to November with peak rainfall in September/November. The secondary rainy season extends between March and May with a peak in April. The main dry season is from December to late March with a secondary dry season between June and July. Evaporation exceeds rainfall in the dry season by a factor of 5. During the rainy seasons, rainfall is greater than evapotranspiration. The behaviour is quite similar for the project sub county.

It should be noted that the above description is based on historical data and climate change processes will result in modifications to the local climate. However, under the same description, the project area of Biguli Sub County falls in climatic zone of ME. The characteristics of the two zones are as detailed in table 3.2. and their location in figure 3.1a.

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Table 3.2.: Hydro-climatic variation in the study area

ZONAL AVERAGE RAINFALL, STD AND EVAPORATION ANALYSIS Zone Districts, 2000 Annual and Main rainy Main dry Evaporation boundaries zonal variability seasons seasons verses rainfall MW Kabarole, Average of 1223 Two rainy Main dry Evaporation > , mm. High seasons, main season rainfall by a Northern variability, season August to December to factor of ~ 5 Rukungiri, lowest ~ 800 November with late March, during the dry Bushenyi and mm Kasese Rift peak in secondary dry months, Valley, highest September to season is December to over slopes of November and June to July. March. During Rwenzori secondary season the rainy months, mountains, over March to May with March, and 1500mm. peak in April. August to November rainfall > evaporation. ME Mubende, Average of 1021 Two rainy Main dry Evaporation > West Mpigi, mm. seasons, main season June rainfall by a Sembabule, season March to to August, factor of ~ 6 and northern May with peak in secondary dry during the dry Rakai April and season is months, June to secondary season January to August. During September to February. the main rainy December with a months, April modest peak in and May rainfall November. ~ evaporation.

Figure 3.1a.: Climatic zoning of the Uganda – DWRM Figure 3.1b.: Location of the Historical rain gauge study stations close to the study area.

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The averaged distribution of the rainfall over the two climatic zones is shown in the bar charts below; the zones are shown in figure 3.2

Distribution for MW zone – Kamwenge District Distribution for ME Zone – Biguli Sub County

Figure 3.2.: Average rainfall distribution patterns over the two climatic zones

3.4 Biophysical data of the study area.

3.4.1 Topography In general there is a distinct variation in topography across the district of Kamwenge ranging from a low 1300- to a high 3800m above sea level. However, on the general outlook, the topography decreases as one transcends Biguli sub county in a North-south direction ranging from 1215m with exception of the ridges that are prominent in the southern boarders at 1494m.

3.4.2 Geology Most of the district (95 %) is underlain by Precambrian Basement complex (metamorphic rocks and some sedimentary formations). A small area in the south-west is underlain by Rift Valley sediments (sandstones, conglomerates, shales) of unknown thickness. Recent sediments (Alluvium, Black soils) are confined to the valley of River Katonga and around Lake George in the west. The main rock unit classification comprises; ▪ Mobilised and intrusive granites ▪ Undifferentiated gneisses of granulite facies and ▪ Phylites and Schists intercalated with basal quartzite and amphibolites

In the project sub county, over 75% of the area is underlain by metamorphic comprising the undifferentiated gneisses, 15% consists of pyhlites and schists with quartzites lenses and veins and these are occurring in the north-western tip of the study area while the rest of the 5% consists of intrusive granites also occurring in the north-western part of the project area.

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The geological map of the study area is shown in figure 3.3 below;

Figure 3.3.: Geological map of Biguli Sub-County.

3.4.3 Soils In general there are 3 types of soils within Biguli predominated by Red gravelly loams underlain by soft laterite, grey sands are long areas of seasonal wetlands, whereas Shallow brown and reddish brown sandy are around the central southern ridge.

3.4.4 Vegetation Most of the land in Biguli Sub-County has been converted in to cattle farms hence the natural vegetation has been tampered with. Therefore the vegetation is mostly short grasslands with scattered trees that are shrub-like.

3.5 Surface water status of the study area

3.5.1 Drainage In Kamwenge District, the drainage is mainly controlled by R. Mpanga that runs through the district as the major river southwards. In the project sub county however, the drainage (as seen from the existing rivers of Rwakasirabo, Kizikibi, Kabaga, Karawhirwe and Nanyinguru) is similar to the district on a regional scale but the predominant flow is in the opposite direction to that of the District. For both the District level and the Sub County level, the drainage is of a dendritic pattern.

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Vol. I – Water Resources Water Resources Assessment of Biguli Sub County in Kamwenge District Assessment Report

Figure 3.4a.: Drainage map of Kamwenge District Figure 3.4b.: Drainage map of Biguli Sub county

A surface water study was carried out in the Kamwenge District and in particular, the four parishes of Biguli Sub County including Kabuye, Biguli, Kampala B and Malere. Key activities that comprised the study included a review of exiting literature including reports published and unpublished.

Data from four historical stations has been compiled and tabulated. The data is from the 1940’s to 1970’s. Unfortunately, the stations are not functioning any longer. The station names and codes are shown in the table 3.2. A review of the rainfall pattern of the project area (Biguli sub county) as seen from existing literature and data sets from two various sources has shown the same trend in terms of seasonality.

Table 3.3.: Location of the old rainfall stations in the vicinity of the study area

Station Name Data Data Period Longitude Latitude Altitude Mean Code From To (Years) annual (mm) 89300120 Nkoma 1943 1977 30 30.6170 0.3170 1305 1,031 89300430 Bulemba 1951 1978 28 30.7000 0.1170 1335 931 89300440 Nyakaliro 1951 1960 10 30.9500 0.1500 1290 864 89300620 Kiburara 1964 1985 22 30.4670 0.0830 1215 1,125

Of the four selected stations, the station at Nkoma is the closest to the study area. Data from this station has been compared with satellite data

3.5.2 Annual Rainfall and Monthly Variations The above stations have been selected to be representative of the study area for 4 stations for the period (1950 -1979). Of the four stations, the station of Nkoma which is located approximately 15km from Biguli sub county Headquarters is the nearest. From the above four stations, variations of the monthly and annual rainfall amount/depths across the entire study area has been represented in the bar chart shown in figure 3.5.

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Spatial Variation of Rainfall over the Study Area 160

Nkoma 140

Bulemba (mm) 120 Nyakaliro

100 Kiburara

Rainfall 80

60 Annual

40

20 Average

0 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Month

Figure 3.5.: Mean monthly rainfall for the stations representing the study area Observation: The station of Nkoma (Nearest to the study area) shows an average annual precipitation of 1,035mm. This station is in the south western direction from the study area (see figure 3.1b) however, to a greater extent it can be said that the study area receives an average annual precipitation of not less than 1,000mm of rainfall.

The variation of rainfall across the sub county is well displayed by the map shown in figure 3.5 below

Figure 3.5.: Aerial distribution of rainfall across Biguli sub county

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Table 3.4.: Mean annual precipitation for the stations in the vicinity of Biguli S/C.

Station ID 89300120 89300430 89300440 89300620 90300080 90300110 WEB BASED NAME Nkoma Bulemba Nyakaliro Kiburara Nyabusozi Kicheche Kampala B N4 1943 1951 1951 1964 1943 1943 N5 1977 1978 1960 1985 1974 1976 LENGTH 30 28 10 22 29 28 LONGITUDE 30.6170 30.7000 30.9500 30.4670 30.8500 30.4830 30.7842 LATITUDE 0.3170 0.1170 0.1500 0.0830 -0.2000 -0.0500 0.3881 ALTIDUDE 1305 1335 1290 1215 1350 1350 JAN 32 33 21 47 49 41 42 FEB 51 43 29 59 47 57 59 MAR 87 75 55 88 91 97 117 APR 130 122 113 121 113 140 143 MAY 79 77 103 114 64 110 105 JUN 41 34 33 50 28 51 51 JUL 46 43 52 43 27 48 51 AUG 81 79 62 100 68 101 93 SEP 124 106 86 136 91 157 149 OCT 143 141 97 144 112 135 160 NOV 114 115 82 137 119 144 140 DEC 68 66 52 51 64 74 71 ANNUAL AVERAGE 1031 931 864 1125 917 1127 1181 TOTALS

3.5.3 Comparison of the Old data and Recent Satellite Data Using web-based date, (data taken from Satellite), rainfall data from the town of Kampala B was retrieved from and compared with the data captured from the Old stations. The data on the satellite is based on the fact that climatic conditions are recorded for very few locations on earth and most of the time, when a (hydrological) study is carried out, data from distant stations has to be used. Comparison of Old data and New Data (Satelite based) for the 180 Study Area 160 Nkoma

140 Kampala B

120

(mm)100

80 60 Rainfall 40 20 0 JAN FEB MAR APR MAMYonJtUhNs of tJhUeLYeaArUG SEP OCT NOV DEC

Figure 3.6.: Comparison of Old data and satellite data

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This tool uses a worldwide dataset of monthly climate to provide an estimate of climatic conditions at locations for which no observations are available. The last column in table 3.2 above comprises data retrieved from the satellite.

From the bar chart two major observations can be drawn; ▪ The web-based data shows more precipitation in Biguli than in Nkoma overall for all the months of the year ▪ The web-based data easily compares with the data from Nkoma station. The trend is similar

The values retrieved from the web based rainfall data easily compare with the data from the existing old stations. As shown in figure 3.5, the study area receives 7 months of rainfall stretching in two seasons. The main season starts in the month of August through to November and the secondary season is March to May. It may be logical to conclude that the amount of rainfall in the project area has not changed that much in the last quarter of a decade.

3.6 Groundwater Status of Kamwenge. The groundwater status of the district presented here was done by DWRM in 2012, from the district groundwater report. The data analysed here focused on the general district and not on Biguli as a Sub-County. Therefore most of the presentation here is more about the district in general.

Groundwater technology options include shallow wells, protected springs and deep wells. Shallow boreholes (i.e. 15 – 30 metres depth) may be used in various parts of the district whereas shallow hand dug wells are limited to the valleys where the water strikes are less than 15 m deep. Springs appear mainly in the south, centre and north-west of the district, but yields in several areas have very low yields and are difficult to capture. Deep borehole drilling is restricted to the south-west and an area in the north-east.

Existing groundwater data has been compiled to acquire mean statistical values of the key hydrogeological parameters including; water strikes, depth to bedrock, borehole depth, regolith depth and yield.

Table 3.5.: Descriptive hydrogeological parameters of Kamwenge District

Depth to Depth to Depth to Depth to Airlift Specific Bedrock FWS MWS SWL Yield Capacity (m) (m) (m) (m) (m3/h) (L/h/m) Min 5.9 8.00 8.00 0.64 0.01 4.00 Max 45.6 65.00 71.00 37.50 20.00 405.00 Average 29.5 28.69 40.18 16.27 3.07 130.50 Median 29.5 27.00 46.00 14.08 1.06 47.50 No. Data Points 21 19 17 22 16 16

In the central part of the District a thicker overburden (30 m, even over 40 m) is found. In the centre and south of the district the overburden is generally thinner (less than 30 m) with small areas of less than 15 m. The FWS and MWS in Kamwenge District are in the range of 30 to 40 m in most parts of the district. Small areas in the central part, in the west and some areas in the north-east have shallow

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Vol. I – Water Resources Water Resources Assessment of Biguli Sub County in Kamwenge District Assessment Report water strikes between 0 to 25 m. In the south-west, north-west and north-east some areas have FWS and MWS over 40 m. Many parts of the district have shallow SWLs less than 15 m. In the centre and north-east areas are found with SWLs between 10 – 25 mbgl and over 30 m.

There is good quality water in the north and south of the district. In the north-east, centre and south, the groundwater quality is problematic (above Maximum Acceptable Values or Guideline Values), brown coloured water is pumped in the morning hours (iron, probably caused by corrosion of pump parts or borehole casing). The key hydrochemical parameters considered are Fluoride, Total Dissolved Solids (TDS), Total Iron and Hardness. Only Total Iron has values above GV and MAV, as mentioned above, all other parameters fall below their respective GVs and MAVs.

The project Sub-County on the other hand has entirely good groundwater quality for the key hydro-chemical parameters. Below is a map of Kamwenge district showing the overall groundwater quality analysed using TDS, Hardness, Flouride and total Iron

Figure 3.10.: Groundwater quality for Kamwenge Figure 3.11.: Groundwater potential for district.. Kamwenge district. Source: Kamwenge District Groundwater Mapping Well yields are generally higher in the northern part of the district. The areas with poor groundwater quality (centre and south of the district) also have poor groundwater potential (few boreholes with yields above 1.0 m3/h) and success rates of 25 - 50 per cent. The north-west has moderate groundwater potential (50 - 75 per cent). Success is low in the centre and part of the south.

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4.1 APPROACH, METHODOLOGY AND WORK DONE

4.2 Approach and Methodology Executing an assignment of this nature requires a multi-prong approach to be able to achieve the study objectives. An approach involving both gathering primary information and secondary information was used at various levels of the assignment. A review of existing reports within Kamwenge district and outside Kamwenge district, reports of previous catchment management studies for the main host catchment of Mpanga within the Albert Water management zone and outside the Albert Water Management zone was done.

The socio-economic baseline survey was carried out in the four parishes of the study area and the sampled areas comprised 30%. All the four parishes forming Biguli Sub County were sampled. The survey embraced both qualitative and quantitative approaches to indubitably understand the actual situation at hand. They focused on obtaining a clear understanding of the influence of water and sanitation on the socio-economic wellbeing of the communities.

Key activities carried out included surveys on the; Socio-economic aspects; ▪ General population data and settlement patterns ▪ Community level of wealth/ level of income/ economic activities ▪ Education including presence of schools and vocational institutions

Water and Sanitation; ▪ Water use patterns, quantity used, collection time, distance and accessibility ▪ Current mode and level of payment for potable water ▪ Current structures/facilities, status, operation and maintenance systems ▪ Water facility management mechanisms ▪ Sanitation; current practices for human excreta disposal, communal and personal level of hygiene, pit latrine use/behaviour and coverage, community health/level of disease burden

The methods employed in carrying out the socio-economic survey included document review, design of a questionnaire to be used for data collection, training data collectors on how to conduct the survey, actual data collection in the field i.e. Biguli sub-county, data entry in SPSS; SPSS was used data analysis, The survey focus areas were the socio-economic status, sanitation status, hygiene practices and water status among others for Households and institutions. Key informant interviews (KIIs) and focus group discussions were also carried out.

For surface water resources, the Mike NAM “Nedbør Afløbs Model” an extension of MIKE 11 developed by DHI was used to build a rainfall runoff model. The Mike NAM is deterministic, lumped and conceptual rainfall-runoff model that operates by continuously accounting for the moisture content in three different and mutually interrelated storages that represent overland flow, interflow and base flow. The model was built and calibrated based on the gauged river flows of River Katonga. The total catchment of River Katonga that contributes to the gauged flow is 13930 sq. kilometres. The model was calibrated based on data for a period of 1960-1969 and validated

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Vol. I – Water Resources Water Resources Assessment of Biguli Sub County in Kamwenge District Assessment Report with data of 1970-1971. The calibrated model was then used to generate flow time series for biguli catchment

The basic input data requirements for the MIKE11 NAM model are meteorological data and discharge data for model calibration, definition of the catchment parameters, and definition of initial conditions. The basic meteorological data requirements are precipitation, potential evapotranspiration and temperature time series. On this basis, the model produces a time series of catchment runoff.

In addition to reviewing all existing data on groundwater of the project area, physical visits were made on ground to qualify the desk study information. Through the use of surface resistivity methods, hydrogeological surveys and geophysical surveys were also conducted in the parishes of Malere and Kampala B with the aim of locating points where drilling of production boreholes could be conducted.

Using ArcGIS, maps were generated to facilitate the study. In general two types of maps were made including;

Simple display maps: Generated to give a generalized display of simplified parameters and or attributes say the type and existing water sources, drainage, population distribution and density etc

Thematic maps: Generated through combining a series of layers. Such maps display a result of processing by use of interpolation techniques and or a combination of these e.g. – the soil erodability map, groundwater flow pattern map, catchment delineation map etc.

Table 4.1.: Input data and the method used in the processing/generation of the map.

No. Map name Inputs Method Comment/Remark Thematic Maps Population density Population, area Populate polygons Generated Sampled Villages Sampled villages Digitizing principally through Stakeholder areas stakeholders Digitizing the acquisition of Drainage –Biguli s/c & Rivers, wetlands, lakes Plotting grid coordinates Kamwenge and plotting on the Existing sources Boreholes, springs, Plotting themes and layers rainwater tanks, Geology geology Plotting Geophysics Sites for drilling, Plotting lineaments Technical field visits Visited areas plotting Raster Maps Annual rainfall Rainfall, Areal interpolation Generated through Depth to bedrock Lithological data Areal interpolation a combination of First water strike Lithological data Areal interpolation one or more Main water strike Lithological data Areal interpolation continuous layers Water quality Bacteriological Areal interpolation over the entire

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No. Map name Inputs Method Comment/Remark Delineated catchment Digital Elevation Model, Modelling area. The layers DEM and mapped are usually in form rivers of raster. Potential for Harvesting Digital Terrain Model, Modelling DTM and mapped rivers Run-off-Pathway Digital Terrain Model, Modelling DTM and mapped rivers Aquifer map Geology, lineaments, Zoning Buffer zones Rivers, wetlands Structured Querry Language, SQL Groundwater potential Wetlands, slope, rivers, Structured Querry lineaments Language, SQL Soil erosion/loss Rainfall, soil erodibility, Map algebra, remote topography, land cover sensing, modelling , land practice Groundwater recharge Groundwater recharge Used raster file “as is” Static water level Lithological data Surfer 8, contouring

4.3 Work Done A series of existing literature and reports were collected and studied. The information and reports studied during the assignment is shown in table 4.1 below;

Table 4.2.: Reports that were collected and reviewed during the study.

# Report Detail Source of Report and Report Date 1 The hydro-climatic study and categorization of Uganda Basalirwa et al DWRM, 2000 (1993) – Unpublished Report 2 Uganda Catchment Management Planning Guidelines April 2014 3 Maziba Sub-Catchment Management Plan, Kabale District, Uganda under October 2014 the Nile Basin Initiative Nile Equatorial Lakes Subsidiary Action Program. 4 Draft Catchment Management Plan for Awoja Catchment in Kyoga Water December 2013 Management Zone 5 Mpanga Catchment Management Plan July 2015 6 Rapid Needs Assessment – Water supply to selected Rural Growth May 2013 Centres in Biguli sub county – Kamwenge District 7 Siting, Drilling and pumping test for Nine boreholes in Biguli Sub county, January 2016 Kamwenge District – Drilling Report by DRACO (U) Ltd 8 Involving local communities in preparing a long term CC and IWRM action June 2011 plan to enhance their adaptive capacity to CC, and integrate improved water management in the Mpanga Catchment of the Nile Basin in Uganda. 9 KAMWENGE DISTRICT GROUNDWATER REPORT-mapping of groundwater resources in Uganda. May 2012

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10 KAMWENGE DISTRICT LOCAL GOVERNMENT- FIVE-YEAR 2015/16 – 2019/20 DEVELOPMENT PLAN

11 Uganda National Water Resources Assessment. Ministry of Water and 2013 Environment (MWE), 12 Hydrogeology of Uganda, Owor, Tindimugaya, Brown, Upton & Ó 2016. Dochartaigh, 13 Water Resources of Uganda: An Assessment and Review, Francis N. W. 2014 Nsubuga1,2*, Edith N. Namutebi3, Masoud NsubugaSsenfuma2 14 THE NATIONAL LIVESTOCK CENSUS REPORT 2008 15 Economic Assessment of the Impacts of October 2015 Climate Change in Uganda, Ministry of Water and Environment

4.2.1 Environment and Social Consideration Survey An environmental survey of the study area was conducted with focus on the aspects that are critical in the catchment management procedures. Ares of focus were both social related, agricultural related, flora/fauna related and aspects of conservation. The details of this survey are presented in Volume II of this report

4.2.2 Groundwater surveys – siting of production boreholes A total of 15 villages were surveyed and 7 potential locations were identified for drilling of production boreholes. Surveys involved the review of existing literature, study and analysis of topographic maps and fired sessions including the running of geo-electric line profiles vertical electric soundings in potential areas. A detail of this work is contained in chapter 5 of this report.

4.2.3 Surface water surveys perennial streams and rivers visited.

Rainfall data was obtained from the Department of Metrology and ten (10) rainfall gauging stations were used to obtain average rainfall and included Madu, Kanoni, Ngando Hydromet Station, Kabasanda, Mpanga Forest station, Katigondo WFM, Kalungu, Butenga, Samaliya, Kiganja, Estate and Bigasa all lying within the Katonga catchment. The areal precipitation of the area was computed from point precipitation by using arithmetic average Method.

The temperatures used in the model were from the nearby areas close to Katonga since there were no series of temperature that rhyme with the period of rainfall and discharge for the periods of 1960-1971 used in model build up. This was done because temperatures do not vary much with location across the equator.

Potential Evapotranspiration (ETo) is one of the important input in development of MIKE 11 NAM model due to its high effect on runoff in the form of evaporation from the surface. The ETo calculator software which is based on FAO Penman-Monteith Method was used for estimation of ETo. The climatological data used to estimate ETo using the meteorological data was maximum and minimum temperatures, and sunshine hours.

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Flow time series for R.Katonga gauged on Masaka-Jinja gauging station draining an area of 13930sq.kilometers were obtained from Water Resources department (MWE) for the period of 1960-1975.

As one of the major deliverable of the consultancy, the project area comprising Biguli Sub -County was delineated into smaller catchments forming the micro catchments. The outline of the sub county was used to determine the extent to the Digital Elevetion Model, DEM (layer) that was cropped. Using this layer a series of processing were undertaken with the help of ArcHydro® and then catchments generated. Several maps representing above surveys were generated as tabulated in table 4.1 above.

Permanent stream flow at the extreme southern Damaged Road culver across one of the roads in parts of Biguli Sub County along the Kizikibi Bisayumbe village (close to the game reserve). stream

Figure 4.1.: Existing surface water resources.

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5.1 RESULTS AND INTERPRETATION

5.2 Socio-Economic Survey The survey findings have indicated the existence of three main issues that should be the focus of the water resources assessment in the project Sub-County. ▪ Agriculture as the main source of income ▪ Commercial farmers ▪ Sanitation and hygiene status

5.1.1 Agriculture In the project area of Biguli Sub County, the commonly grown crops include Matooke, irish potatoes and maize. These crops serve both as a food crop and cash crop. Matooke growing is mainly in the parishes of Kampala B and Malere. The parishes of Kabuye and Biguli also grow Banana but on small scale. The element of commercial farming is only as a result of the excess Matooke grown that is sold.

Irish potatoes harvest in Muyumya Banana and coffee intercropped in Maize garden in in the outskirts of village the outskirts of Kampala B centre Kampala B Village

Figure 5.1.: Commonly grown crops in Biguli S/C.

Livestock rearing is rather common in the in the parishes of Biguli and Malere. The livestock is mainly in the highland areas where growing of crops is considered challenging.

5.1.2 Commercial farming Although there is a lot of crop farming in the project area, farming is being carried out on very small scale. Farmlands of not more than 2 acres of land are what are common. This however is the trend of farming in the rural areas of the country.

5.1.3 Sanitation and hygiene

5.1.3.1 Sanitation Coverage There is a high level of awareness of the need to have an improved sanitary facility. This is shown by the high number of respondents that had a sanitary facility in their homes. Out of 409 households, 2,067 had access to a sanitation/excreta disposal facility whereas 28 households did not have. This focused on actual presence of an Excreta Disposal Facility in a household not the quality of the facility.

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Figure 5.2.: Presence of an Excreta Disposal Facility, EDF, in the project area.

Of the 409 households, 1,938 households had traditional pit; 102 had Ventilated Improved Pit latrines; 18 had flush toilets and 9 ECOSAN toilets. All together these form 2,067 households with at least an excreta disposal facility. However 28 households were found not to have EDF. Therefore basic sanitation stands at 99%4.

5.1.3.2 Hand Washing Facilities At both household and institutional levels, the presence of a Hand Washing Facility (HWF) was captured during the survey. In addition to the presence of the facility, the survey further captured the presence of soap at the HWF. The survey findings are that only 37% of the respondents had a HWF and of the 37% respondents, 96% (746 out of 778) had soap at the HWF. In the study area, the communities that have embraced the concept of hand washing also have appreciated the need to wash hands with soap.

5.1.3.3 Safe water coverage Within the study area, the safewater supply technology options include the traditional technologies like protected springs, shallow wells and deep boreholes. However, through the survey, it was established that in addition to the safe water technologies, there exist some un-protected water sources that the communities use for water including open water holes, ponds and surface water from streams and rivers and perennial wetlands.

The safewater coverage of Biguli sub county stands at 25% as of June 2016.

5.1.4 Sampled villages. The District Development Plan of Kamwenge district shows that the sub county of Biguli has a total of 41 villages while the surveys previously conducted by W4P show the sub county to have a total of 40 villages. During the field exercise, several points were visited by all the teams across the sub county. Since the project was focusing on Malere and Kampala B, most areas visited are in this sub county. Figure 5.2 shows the distribution of the villages that were visited across the sub county.

4 Basic Sanitation was derived as a percentage of households with EDF of the total number of households

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Figure 5.3.: Sampled areas for social survey.

5.1.5 Readiness to receive water This component was rather assessed indirectly by getting the community’s preferred source of water. In the sampled households, out of 2,095 households 470 preferred borehole, 9 rain water, 175 preferred river water, 37 preferred lake water, 46 preferred protected springs, 1,312 preferred tap water and finally 46 preferred shallow wells.

Figure 5.4.: Preferred sources of water at Household.

5.1.6 Willingness to pay for the water and the Cost of water The survey established that 87% of the population was willing to have access to piped water as compared to 13% who were not and further more although the communities may be willing to pay a tariff that puts the jerrycan at less than 100 Shs may be easily acceptable to the users.

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In economic terms, demand may be defined as need backed by ability to pay for the need. Whereas the respondents may indicate that they need safewater and are willing to pay for the safe water, it is important to assess their ability to pay for the need. In this case, this parameter is a good indicator in assessing the actual “demand” for the safewater service within the project area. The table above shows categorization of the cost households incurred in purchasing one jerrycan of water.

5.2 Surface Water Resources In chapter 3 of this report, the surface water resources of the study area were presented and an analysis of the variation of the monthly distribution of rainfall received in a year was also discussed.

5.2.1 Catchment Yield The hydrologic response of catchment to rainfall, estimates of catchment yield, and runoff data are of vital importance for hydrological analysis for the purpose of water resources planning, flood forecasting, pollution control and many other applications. In most river catchments that are ungauged or with limited discharge data rainfall-runoff model can be developed to simulate the natural hydrological processes to estimate the runoff from the catchment. The Mike NAM model was built and calibrated based on flow time series from 1960-1969 and validated based on 1970- 1975 data series. The model gave a coefficient of determination (R2) of 0.64. This is used to indicate the proportion of variance between the simulated and observed flows.

80

Qobs 70

(m3/s) 60 1960- Observed Simulated 1969 (Mm3) (Mm3) Difference 50

flows

40 186.8 172.8 -1.07%

30 R^2 0.64

monthly

20

10 Average

0

8/1/1965

8/1/1960 1/1/1961 6/1/1961 4/1/1962 9/1/1962 2/1/1963 7/1/1963 5/1/1964 3/1/1965 1/1/1966 6/1/1966 4/1/1967 9/1/1967 2/1/1968 7/1/1968 5/1/1969

3/1/1960

11/1/1961 12/1/1963 10/1/1964 11/1/1966 12/1/1968 10/1/1969 Time

Figure 5.5.: Simulated and observed discharge time series for R. Katonga

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Cumulative Observed Discharge (m3/s)

Cumulative Simulated Discharge (m3/s) 30000

25000

20000

(m3/s)

15000

10000

Discharge 5000

0

Time

Figure 5.6.: Water balance for the calibrated model The water balance was closed based on the model calibration. This is important in reservoir analysis and indicates that the simulated flow discharge after 10 years is equivalent to the observed.

The catchment yield was estimated based on the calibrated and validated model for R. Katonga. Since the Mike NAM model is a deterministic, conceptual lumped rainfall runoff model, it’s assumed that all the hydrological processes are the same. Therefore, flow series to estimate the catchment yield for Biguli was generated by using catchment the catchment size of 284 sq. kilometres.

0.7

) 0.6

3 m

0.5

(million 0.4

volume 0.3

flow

0.2

Monthly 0.1

0.0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 5.7.: Potential flow volumes likely to be generated from Biguli Sub-County

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The average flow volumes are highest in the months of April to May and November to December and lowest in the months of Feb to March and July to October. This is attributed to the rainfall patterns.

1.2 Probability of Flow Flow exceedance (m3/s) (m3/day) 5 0.4349 37576.47

/s) 0.8 10 0.3233 27934.52 3

(m 20 0.2117 18292.57 0.6 50 0.0642 5546.595

Flows 80 0.0046 397.44 0.4

Daily 95 0.0008 69.12

100 0.0003 25.92 0.2

0.0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Probability of exceedance

Figure 5.8.: Biguli yield variation curve against probability of exceedance. Based on the exceedance values, it can be seen that even during dry years (probability of exceedance ≥80), there are significant volumes of water that can be generated from the catchment. This is very important with regard to water abstractions for animals and domestic use.

100000 Peak flows Return period

(m3) (years) 90000

91968.19 15.3 (m3)

80000 70000 76166.44 7.7 60000 52945.76 5.1

volumes 38043.92 3.1 50000

31036.20 2.6 flow 40000

30000 26747.98 1.9 Peak 20000 23415.51 1.5 17388.38 1.3

Daily 10000 11439.36 1.0 0 0.5 5 50 Return Periods (years)

Figure 5.9.: Daily Peak flow volumes from Biguli against return periods From time to time, it can be seen at least every year there are peaks in flows that are experienced. This is also important for reservoir storage as it gives an indication that there are significant amounts of surface runoff that can be tapped for storage.

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Low flows Return period 12000.0 volume (m3) (years) 28.87 15.3 10000.0

28.87 7.7

(m3)

8000.0 59.04 5.1

213.09 3.1

6000.0 346.51 2.6 volumes 417.48 1.9 4000.0

flow 658.97 1.5

2502.57 1.3 Low 2000.0 10525.95 1.0

Daily 0.0

0.5 5.0 50.0 Return Periods (years)

Figure 5.10.: Daily low flow volumes from Biguli against return periods From the analysis of low flow volumes, there are occurrences of low volumes experienced in the flows. This is attributed to the size of the catchment being small and also the dry seasons.

5.2.2 Catchment delineation To better understand the occurrence and variation of the surface water resource, the project area has been delineated into six (6) sizeable sub catchments as shown in figure 5.11

Figure 5.11.: Delineated micro catchments for Biguli sub county.

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Worth noting is the fact that the delineated six micro catchments cover only 99.5% (166.3km2 out of 167.2km2) the entire sub county Computations of the surface water flow (80% exceedance) for the six micro catchments has been carried out and the outcomes are presented in section 5.2.3

5.2.3 Available surface water resources The total annual volume of rainfall received in Biguli Sub County has been computed. The annual rainfall amounts for the various catchments has been estimated and shown in table 5.1.

Table 5.1.: Estimate annual rainfall amount and volumes for each catchment

Catchment Total Area Rainfall Available annual Volumes # No.: Catchment Name (m2) (mm) (m3/Year) 1 Biguli Sub County 167,950,000 1075 180,546,250 2 1 Nayinguru 18,196,000 1150 20,925,400 3 2 Rwakasirabo 37,950,000 1050 39,847,500 4 3 Upper Kabaga 3,520,000 1025 3,608,000 5 4 Kizikibi 35,110,000 1050 36,865,500 6 5 Kabaga 43,110,000 1000 43,110,000 7 6 Karawhire 28,440,000 1000 28,440,000 TOTAL FOR ALL CATCHMENTS 166,326,000 1075 178,800,450

The volume indicated may be considered as the annual renewable water resources of the sub county. For this to hold we have to assume that since the sub county is located in the extreme “up-stream” of the catchment, then the lateral flow may be ignored.

5.2.3 Exploitable surface water resources In determining the exploitable surface water resources, a rather conservative approach has been used. A flow that coincides with the 80% exceedance (see figure 5.6) was adopted so that the volumes computed are rather more realistic. From this assumption, the available exploitable surface water volumes are shown in the table below;

Table 5.2.: The computed surface water flow in the six catchments of the study area.

Catchment Total Area Flow Available Annual # No.: Catchment Name (m2) (m3/s) Volumes (m3/Year) 1 Biguli Sub County 167,950,000 0.0046 145,066 2 1 Nayinguru 18,196,000 0.000498372 15,717 3 2 Rwakasirabo 37,950,000 0.001039416 32,779 4 3 Upper Kabaga 3,520,000 9.64096E-05 3,040 5 4 Kizikibi 35,110,000 0.000961631 30,326 6 5 Kabaga 43,110,000 0.001180744 37,236 7 6 Karawhire 28,440,000 0.000778946 24,565 GRAND TOTALS 166,326,000 0.00455552 143,663

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The total available annual volumes of surface water resources available (at 80% exceedance) are 143,663 m3/year. Assuming that the maximum flow is experienced every year, the maximum anticipated flow (at 5% exceedance) is computed to be 13,715,006 m3/year.

5.2.4 Development of Surface Water Resources Harvesting of surface runoff through dams and valley tanks has not been done within Biguli Sub County. Suitable locations for the development of dams have been proposed and the spatial distribution of the proposed potential locations is shown below in figure 5.12.

Figure 5.12: Proposed potential location of Water for Production facilities.

The study area has potential for construction of large surface water reservoirs. For effective and costly implementing of this recommendation, the development partner may partner with government especially in terms of accessing the earth-moving equipment for this task.

5.2.4 Key conclusions and recommendations on the surface water resources The lack of reliable and recent rainfall data within the project area makes the analysis of surface water resources within the project area a rather complicated scenario. In the times gone by, there used to be a good network of rainfall stations in the vicinity of the project sub county, these stations are defunct and have been non-operational for more than 20 years. There is need to establish a network of simple rain gauge stations (at least one in each parish) so that “first hand” data is captured for future data analysis and modelling. If possible stream flow gauge measurements may also be made especially at the few existing perennial stream in the southern parts of the sub county.

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However, with all the above setbacks, rainwater harvesting may be implemented at selected locations within the study area as shown in figure 5.13

Figure 5.13: Simple rain gauge station and flow monitoring station (gauge). A fully fledged automated weather station should be put up in the region so that information regarding the evaporation, sunshine hours and rainfall intensity are correctly captured. This station should be installed at Nkoma Sub County HQs. Though outside of the study area, this location has some old rainfall data and therefore future studies can make use of this information and more.

5.3 Groundwater resources

5.3.1 Identification of Potential Locations for drilling of production wells Resistivity Profiling The profiles show the study area to have relatively apparent resistivity values showing a large variation from as low as 50 ohms to as high as 800 ohms thus the change along the resistivity profile once a lineament has been intercept is easy to notice.

Butamba Geo-Electric Line Profiles 650 Line 1 550 Line 2

450 Ohm)

(m 350

250

Resistance 150

50 0 50 100 150 200 250 300 Distance (m)

Figure 5.14.: Sample results of the geophysical survey results – Line profiling

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Vertical Electric Soundings (VES) Curves. There is a large disparity (over a small change in ground distance) between the shapes of the resistivity signatures captured during the field exercise and although a typical “inverted S” curve would have been desired (refer to figure 5.5), a series of different shapes of curves were generated during the plotting. Most of the VES curves showed apparent resistivities between 10 and 100 Ohm-m. A typical set of results obtained is shown in figure 5.15

Butamba Sounding Curves 1000

VES 006

m) - VES SPOT1

m

VES 003 (Oh

y

100

sistivit Re

t n

are pp

A

10 1 10 100 AB/2 (m)

Figure 5.15.: Sample results of the geophysical survey – VES sounding

Locations Identified For Drilling Of Production Wells As one of the project outputs, sites have been identified through the hydrogeological assessment and geophysical investigations where drilling of production wells will be implemented by W4P. A total of 7 sites have been earmarked for this exercise. During the surveys, a total of 17 locations were investigated and only 7 locations showed good results worth carrying out test drilling to ascertain the groundwater potential and availability. The details of all the investigated locations are shown in the table 5.2

Table 5.3.: Villages where detailed borehole site surveys were conducted

Parish Location Remarks Malere Rwakasirabo Good results obtained for drilling Butamba Good results obtained for drilling Kagorora Good results obtained for drilling Kanyegaramire Good results obtained for drilling Munyuma Poor results obtained Kagoyigoyi Poor results obtained Malere B Poor results obtained Lyantungo Calibration geophysics Keishunga Calibration geophysics Kampala B Binemba Good results obtained for drilling Ibuga Good results obtained for drilling Nyakatoma Good results obtained for drilling Mukafunda Poor results obtained Busimiro Poor results obtained Soweto Calibration geophysics

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The recommended drilling details for each of the selected sites are presented in table 5.2. It should be noted however that these descriptions are subject to change during the actual well development and there is necessity to have a drilling supervisor deployed in the field on a full- time basis to oversee the drilling activities. The site-by-site recommendations are shown below;

Table 5.4.: Villages identified for drilling and the expected detailed drilling parameter

Expected Expected Expected Expected Anticipated Casing Class First Water Fracture Completion Casing Size Water Strikes Zone(s) Depth(m) Depth (m) (mm) Strike (m) (m) 15 – 20 30 – 45 Lwakasirabo 10 – 15 27 – 40 95 95 156 C-2 60 – 80 60 – 80 15 – 20 10 – 19 Butamba 7 – 13 30 – 40 27 – 40 95 95 156 C-1 60 – 80 60 – 80 Kagorora 15 – 20 30 – 45 30 – 45 60 60 156 C-4 30 – 40 Kanyegaramire 15 – 20 30 – 60 80 80 156 B-2 50 – 65 Binemba 18 – 25 35 – 55 30 – 60 70 70 156 B-1 15 – 20 30 – 45 Ibuga 10 – 15 27 – 40 95 95 156 C-3 60 – 80 60 – 80 Nyakatoma 27 – 40 40 – 60 30 – 60 80 80 156 A

5.3.2 Groundwater data Simple interpolated maps have been generated from this information to give an overview/trend of the variation of each of the parameter across the study Sub-County. Data from the neighbouring Sub-Counties and districts has also been used while generating these maps as shown by the data density map indicated in figure 5.16 below.

Figure 5.16.: Data density for the interpolated maps presented in this chapter

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A total of 50 data points (located within the vicinity of the Biguli sub county have been used in the generating of these maps and the distribution of the data set by district includes; ▪ 17 data points from Kamwenge district including 15 data points from the sub county of Biguli sub county. ▪ 7 data points from and ▪ 26 data points from Kyegegwa district

5.3.3 Spatial variation of First Water strike and Main water strike By definition, the drilling depth at which water is first struck during the drilling process is called the First Water Strike (FWS), while the Main Water Strike (MWS) refers to the depth at which the most significant amount of water is encountered during the drilling process.

In regolith aquifers and “transition to bedrock” aquifers, there is usually a marked difference between the two drilling depths. Figure 5.17 shows maps of the project area (using the same legend for a proper contrast) with the two parameters interpolated across.

Figure 5.17.: Variation of First and Main Water Strikes in Biguli S/C.

The key observation that can be drawn is that the first water strike is mostly between 15 - 30m within the entire project Sub-County except for a few areas in Biguli and kabuye parishes where it is between 30 and 40m. The main water strike is mostly between 30 – 40m in the parishes of Kampala B and Malere whereas in the parishes of Kabuye and Biguli it is mainly between 15- 30m.

There is quite a close resemblance of the first and main water strike maps in the parishes of Biguli and Kabuye as presented in figure 5.18. The maps show that areas with relatively shallower first

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Vol. I – Water Resources Water Resources Assessment of Biguli Sub County in Kamwenge District Assessment Report water strikes are closely associated with relatively shallower depths to the main water strikes. These water strikes are however subject to drilling technique and observation while drilling.

5.3.4 Spatial variation of depth to bedrock and airlift yield By definition, the depth to bedrock is the documented depth at which a competent lithological formation is encountered during drilling while the airlift yield refers to the estimated volume of water that the drilled well is able to provide (usually presented in litres/hours or m3/hr).

It is observed that, over 80% of the target parishes for geophysical investigation, of Kampala B and Malere (within Biguli sub county) show depths to bedrock being less than 30m. In general terms, a thin regolith has a direct impact on the groundwater potential of and area because of the low infiltration and storage of the groundwater. The information displayed on the two maps does not show any relation between the two parameters. Areas with relatively low borehole yields are occurring spontaneously across the study area. Compared to the depth to bedrock estimate, no clear comparison can be drawn.

These values have been computed based on the data in the National Groundwater Database. Notably there are areas of green spots in the northern reach of the study area indicated as low yielding.

Figure 5.18.: Variation of depth to bedrock with total estimated yield in Biguli S/C.

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5.3.5 Hydro-Geostatistical Analysis

Table 5.5.: Descriptive geo-statistical analyses for the existing hydrogeological data

(N = 50) Completion Casing Depth to Airlift First Main Static Depth Depth Bedrock Yield Water Water Water (m) (m) (m) (m3/hr) Strike (m) Strike (m) Level (m) Minimum 45.00 5.60 6.00 - 12.00 12.00 1.87 Maximum 153.11 127.00 64.60 15.30 114.00 114.00 54.60 Mean 81.51 35.12 30.53 2.07 47.29 53.65 21.45 Median 78.44 33.83 27.50 1.00 42.00 51.85 20.94 Mode 93.50 30.00 24.00 0.80 40.00 57.00 31.15 Standard Deviation 24.25 20.32 13.22 2.93 23.27 24.72 11.58

Observations ▪ Across Biguli Sub County, the statistical analysis of the existing borehole data shows that; ▪ The maximum borehole depth is 153m while the minimum is 45m. The average depth stands at 82m. ▪ The extent of weathering (as depicted by the casing depth) ranges between 5.6m to 64m with an average depth to weathering of 30m. ▪ The depth to static water level varies between 1.8m to 54.6m, with the average of 21.45m. ▪ The computed airlift yield shows a maximum airlift yield of 15.3m3/hr. the maximum reported test pumping yield is 19m3/hr.

Based on the above observations it suffices to say that boreholes in the project sub county are drilled and completed in the bedrock and that the weathering profile within the same area is very thin. Therefore target aquifer should comprise both the transition zone and the fractured bedrock. Scatter plots to investigate any relation between depth and yield, casing depth and yield and standing water level and yield were generated. The plots did not reveal any relationship between these hydrogeological parameters.

Further plots to show the relationship between depth to bedrock and water strikes showed that both the first water strike and main water strike occur at shallower depth (DTB< MWS) as shown in figure 5.19

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Variation of Main Water Strike with Depth to Bedrock 100 90

80

(m) 70

60

Strike 50

40 Water

30 First 20 10

0 0 10 20 30 40 50 60 70 80 90 100 Depth to Bedrock (m)

Figure 5.19: Variation of water strike with bedrock depth

5.3.6 Assessing the Water Quantity (Test Pumping) Existing test pumping data was analysed as part of the assessment. Of potentially more use was the analysis of the water level measurements made during the test. The shape and changes in slope of the drawdown were plotted on log-log plots and latter categorized.

In this grouping, three major classes were derived the distribution of which are tabulated. The curves are able to reveal the presence of various hydraulic features in the water bearing zone in the vicinity of the well. Because observations were made in the test wells and that the construction details of the well show the wells to tap water from various water zones, the well test results were taken to be representative of only the environment in the well vicinity and not the entire aquifer system. This was for 15 boreholes.

Table 5.6.: Log plots of test pumping results used to characterise the aquifers.

Typical plot Inference – Aquifer system

CLASS A – 4 boreholes: 100.00 Test Pumping Results - DWD 51601 Characterised by;

(m) ▪ Contribution to the flow in the well is from

10.00 numerous water zones. ▪ Steady drawdown change in the first 80 minutes

Drawdown followed by a sharp increase in drawdown. ▪ Contribution to the well is from more than water bearing zone. 1.00 ▪ Three distinct water bearing zones are evident 1 10 Time (1m0i0nutes) 1000 10000 and depicted by the changes in the plot

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Typical plot Inference – Aquifer system

CLASS B – 10 boreholes: 100 Test Pumping Data - DWD 51599 Characterised by;

(m) ▪ A steady drawdown for the entire duration of the

test 10 ▪ Located in a highly permeable fracture system ▪ Permeability of the surrounding country rock is

Drawdown lower than that of the fracture ▪ Tends to show a scenario of infinite aquifer 1 system with no direct recharge from open water 1 10 Time (1m0i0nutes) 1000 10000 bodies

CLASS C – 1 borehole: Test Pumping Results - DWD 41421 100.00 The curve is characterised by;

▪ Increasing drawdown for the first 80 minutes (m) followed by some tendency of stabilisation and 10.00 then increased drawdown. ▪ Some side contributions to the main aquifer

Drawdown ▪ Different aquifer contributions or an indication of the well hitting a boundary. 1.00 1 10 Tim1e00(m) 1000 10000

From the well tests conducted, the following was observed; ▪ It is rather difficult to analyse data from a test well and be able to obtain the K,T and S values that can be considered representative of the aquifer because; ▪ The borehole drilling carried out aims at maximising the yield of the well therefore tapping of numerous water zones is a common practice. It is necessary that a thorough test should involve the use of an observation well. ▪ Not all basement aquifers are penetrated fully during the drilling as the choice of the completion depth is subject to the airlift yield and formation encountered among others.

5.3.7 Groundwater Quality The groundwater quality of the district shows extensive areas with good quality water in the north and south of the district. However in the north-eastern and south central part of the district, there are groundwater quality problematic areas mainly caused by high iron concentrations.

5.3.7.1 Physio-chemical quality The cationic composition is nearly equal for both the Na+ and Ca2+ and Mg2= ions. The plotted samples have the same shapes and only the individual concentrations are varying with exception of one sample for a source in Kyegegwa District. However the source is quite old as shown by the borehole number “CD 3224”. This borehole was constructed and completed with steel casings and this could be affecting the present quality hence the marked difference in concentrations.

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From the analysis of the existing water quality results, it suffices to say that the physio-chemical groundwater quality in the study area is of good and acceptable quality for both domestic and agricultural use. The water type is basically bi-carbonate water. However, the potential threat to the quality of the water is the contamination resulting from the anthropogenic factors.

Semi-log plot of the major cations and anions have been done and the diagrams are shown in figure 5.20a and b.

10.00 Concentration of the Major Cations Concentration of the Major Anions 10.00 KYG 9 KYG 9 KYJ 3 KYJ 3 KYG 11 1.00 KYG 11 KYG 12 KYG 12 KYG 13

KYG 13 1.00 KYG 14

KMW 2 KYG 14 0.10 KMW 2 KYG 15 KYG 15 KYG 17

KYG 17 0.10 KYG 18 (mmol/l)

0.01 (mmol/l)

KYG 18 KMW 4

KMW 4 KMW 5

KMW 5 KMW 7 ation KMW 8 0.00tr KMW 7 0.01 n KMW 8 KMW 9 ce KMW 9 KYG 19 KMW 10

KYG 19 Con 0.00 KMW 10 Concentration Cl- F- HCO3- SO42- NO3- 0.00 Anions Na+ K+ CaCtai2o+ns Mg2+ Fe-Total

Figure 5.20a.: Concentration plot of the major anions Figure 5.20b.: Concentration plot of the major cations

5.3.7.2 Bacteriological quality Across the district, the use of traditional water sources is being practiced in all sub counties. Surveillance data from W4P for bacteriological analysis has shown that the water sources of the district are prone to bacteriological contamination.

A plot of the bacteriological content of water sources in the project area of Biguli Sub County has been done and the results are shown in figure 5.21. The guideline value for E Coli content is 0 counts. Plot indicates that contamination is prevalent in both the protected water sources and the unprotected water sources.

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120 E Coli variation in Biguli Sub County

100

80

t 60

Coun

Coli 40 E 20

0 Yes No No No No No No No No No No Yes Yes No No No Yes Yes No No No No Yes Yes Yes Yes Yes Protected/Unprotected

Figure 5.21.: Variation of E Coli on sampled water sources in Biguli sub county.

The physio-chemical groundwater quality in the study area is good and acceptable for both domestic and agricultural use. The water type is basically bi-carbonate water. Bacteriological quality of groundwater in the study area is not dependent on the level of protection of the source. Bacteriological contamination has been observed in both the safe and protected water sources and in the unprotected water sources. Also un-protected sources with no bacteriological contamination have been observed. According to the results studied, the potential threat to the quality of the water is the contamination resulting from human activity and influence.

The study has not been able to estimate the groundwater recharge in the entire study area because the information available is insufficient to allow for the approximate computation. The available estimate from DWRM gives an amount ranging between 152mm – 176mm in the southern reach of the study area to 176mm in the northern parts of the study area. In arriving at the above figure, the following assumptions have been made;

▪ The regional precipitation is even irrespective of the differences in the terrain ▪ The amount of runoff is uniform and the effects of soil type, vegetation cover and topography though significant are assumed to smooth out over such a large study area ▪ Evapotranspiration across the study region differs.

Of utmost importance is the fact that the occurrence of groundwater in the project area is limited mainly to the unconsolidated overburden and the transition-to-bedrock zone and rarely in the fractured bedrock. Using the standing water levels in the wells, a groundwater flow direction map has been generated as shown below,

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Figure 5.22.: Groundwater flow direction in the study area

5.3.8 The groundwater resources of the study area. Using the national groundwater recharge map (DWRM 2002), a groundwater recharge map for the study area (Biguli Sub County) was generated. The map has been used in the computations of the groundwater resources in each micro catchment. Using figure 5.9 as a reference, a computation of the recharge based on the delineated micro catchments has been done and the results are shown in table 5.7. The computed exploitable groundwater volumes are shown in table 5.7

Table 5.7.: The computed groundwater recharge volume

Catchment Catchment Total Area Estimated Annual Computed Total No.: Name (m2) Recharge (mm) Recharge (m) annual Recharge (m3) 1 Nayinguru 18,196,000 176 0.176 3,202,496 2 Rwakasirabo 37,950,000 176 0.176 6,679,200 3 Upper Kabaga 3,520,000 176 0.176 619,520 4 Kizikibi 35,110,000 176 0.176 6,179,360 5 5 Kabaga 43,110,000 160.4 0.1604 6,914,844 6 6 Karawhire 28,440,000 158 0.158 4,493,520 GRAND TOT AL 28,088,940

The total available annual volume of groundwater resources is 28,088,940 m3/year.

5 Average value adopted 6 Average value adopted

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Location of the groundwater resource – aquifer systems of the study area.

A model first developed by Dr. Jiri Krasny and Dr. John M. Sharp, Jr (2003) describing the occurrence of groundwater in some Eastern parts of Uganda can be adopted – but with caution- due to the limited available groundwater exploration information that can be used to improve the model.

This model has been modified to accommodate the present conditions in the study area. Factors such as the geology and the topography with some test wells included have been used to modify the model developed. The generated schematised groundwater occurrence model is shown in figure 5.23. on the overall consideration, three factors easily account for the occurrence of groundwater in the study area and these include;

▪ The topographic setting (of the target location) ▪ The geomorphologic setting (of the target location) ▪ The proximity of the target location to the existing perennial or seasonal water courses.

Well No. 4 Well No. 3

Well No. 2

Well No. 1

Figure 5.23.: Schematised groundwater occurrence model in the study area

Explanatory Notes:

Well No. 1 Located in the superficial sediments/alluvium: This well will have a high yield and good storage. In the study area this well represents the successful wells tapping shallow aquifers near to or in the alluvium regions. This was found to be the best location for development of high yield production wells.

Well No. 2 Situated on the periphery of a permanent/seasonal water course (wetland): This well is tapping from the shallow aquifers, the overburden and the transition-to-

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bedrock zone. The well will have a high and sustainable yield. This location too is appropriate for the location of a production well.

Well No. 3 Though drilled through the weathered zone and transition zone, the well is expected to be either low-yielding (less than the threshold) or dry.

Well No. 4 This well is not expected to yield substantial amount of water though locate on a fracture because the preferential flow is towards the low-lying areas within the study area.

Of utmost importance is the fact that the occurrence of groundwater in the project area is limited mainly to the unconsolidated overburden and the transition-to-bedrock zone and rarely in the fractured bedrock. Finally rock units in the study area have been classified based on their ability to yield water. The aquifer classification considered the aspects of primary and secondary porosity and the output has been presented in amap as shown in figure 5.24

Figure 5.24.: Aquifer systems of the study area.

5.3.4 Key conclusions and recommendations on the groundwater resources The groundwater resources of the study area have been reviewed and some points have been identified where drilling of production wells can be implemented. The existence of secondary strictures in the study area greatly enhances the occurrence of the resource. On the general overview, the flow is from the northern parts to the southern parts and the recharge varies in the same direction. The amounts of recharge are significantly higher in the northern reach. In terms

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of abstraction (on the contrary) the southern parts of the study area are better suited for any large scale abstraction of groundwater through boreholes. With an average airlift yield of 3.0m3/hr, the study area has a relatively low potential for high yielding boreholes

The quality of the resource (as seen from the existing data) is good and the significant threat are more of human-induced than any existing natural factors.

5.4 Total Available Water Resources Both the groundwater and surface water resources have been combined to generate the total available resources as indicated in the table below;

Table 5.8.: The total available water resources in the study area

Total Available Resources

Catchment Catchment Available Resources (m3) No.: Name Surface Water Groundwater Total (80% exceedance) 1 Nayinguru 15,717 3,202,496 3,218,213 2 Rwakasirabo 32,779 6,679,200 6,711,979 3 Upper Kabaga 3,040 619,520 622,560 4 Kizikibi 30,326 6,179,360 6,209,686 5 Kabaga 37,236 6,914,844 6,952,080 6 Karawhire 24,565 4,493,520 4,518,085 GRAND TOTAL 28,232,603

However to improve the argument of the available water resource in the project Sub county, two scenario have been considered including • Assuming 80% exceedance • Assuming 5% exceedance For each of the scenarios the groundwater contribution has been kept constant. The contrast for both scenarios is shown in the table 5.8 below;

Volume of Groundwater Total Percentage of Total Surface flow Resource Renewable Resource

Scenario I (80% exceedance of 143,663 28,088,940 28,232,603 16% surface flow Scenario I (5% exceedance of surface 13715450 28,088,940 41,804,390 23% flow

Calculated Annual Renewable 178,800,450 Resource

In principal the water resource that can be tapped or harvested and stored is only up to 23% of the internally generated/renewable water resource within the project sub county.

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6.1 CHALLENGES Executing a project of this magnitude and nature one is bound to encounter challenges some of which directly affect the output and results while others will indirectly affect the outputs. A few of the challenges encountered and the possible effect on the study are highlighted.

6.2 Project Duration Initially, the project duration was only two months. Through this period, raw field data had to be gathered, archived, analysed and reports prepared. Notwithstanding, the assignment is dealing with hydrological and hydrogeological data. In some cases collecting such related data requires at least a hydrological year.

During the course of implementation however, it was realised that more a time was required for proper execution of the assignment. In close consultation with the Client. the project duration was reviewed to cater for the non-eventualities.

6.3 Existing Data Although some data was secured and used in the study, the quality of the data is somehow an issue that cannot be ignored. Under such conditions the analysis results cannot be more accurate than the input data. It is proper that future projects should consider generating some of the data in the field to qualify or quality assure the existing data.

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7.1 CONCLUSION This report is the first of two sets of the study deliverables and this volume is dedicated to the water resources assessment undertakings that have been carried out by the study team. To better review the output of the assignment, the conclusions and recommendations have been presented against the main tasks of the assignment as presented in the Terms of Reference issued by the client.

7.2 Literature Review Conduct an in-depth study of the existing data and literature available for Kamwenge and particularly Biguli Sub County regarding its hydro-geological conditions.

A comprehensive desk study of existing literature both surface and ground has been conducted. Chapter 3 of this report presents a detailed account of the same including socio-economic related, surface water related and ground water related literature.

The hydrogeostatistics of the study area depict a low potential for high yielding boreholes with an average well yield of 3.0m3/hr. the potential of groundwater is relatively low and the development of high yielding boreholes may be conducted but a low success rate is anticipated.

7.3 Socio-Economic Survey Carrying out a socio-economic baseline survey in all parishes of Biguli Sub County through field visits and interviews to determine community readiness for water supply including; willingness and affordability of water services

A socio- economic survey was conducted focusing principally on the communities’ readiness to receive a water supply and the ability to pay for the water. Aspects of sanitation and hygiene were included in the survey. As seen from the respondents’ feedback, the community of Biguli Sub County are ready for the service and willing to pay for the service. A willingness to pay of 87% was established by the survey however a proper tariff should be set so that the water can be affordable to the users.

7.4 Hydrogeological Survey Conduct a hydrogeological survey including determining; groundwater potential; flow rate, existence of fractures or faults, confined/unconfined/leaky aquifers, alluvial aquifers, typical potential formations/rocks, geological unconformity, potential geological structures among others. And make recommendations and a list of possible sites for production wells for piped water systems in the unserved areas as well

A comprehensive hydrogeological survey was conducted with help of topographic maps (1:50,000 scale) and other information from geological maps. Ta total of 7 potential sites for the development of production boreholes were identified and their locations are presented in the table below;

Location Expected Completion Anticipated Casing Depth (m) Depth (m) Lwakasirabo 95 95 Butamba 95 95 Kagorora 60 60 Kanyegaramire 80 80 Binemba 70 70

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Location Expected Completion Anticipated Casing Depth (m) Depth (m) Ibuga 95 95 Nyakatoma 80 80

In addition to the drilling locations, several maps were generated including maps showing;

▪ Groundwater recharge ▪ Groundwater flow direction ▪ The inferred aquifer systems ▪ Interpolated maps showing the variation of water strikes ▪ Interpolated maps showing the variation of the depth to bedrock and

7.5 Surface Water Survey Conduct surface water survey and mapping including; water shed and buffer area characteristics; land use cover, type and size of aquifers threats to the water source, existing and proposed water source protection measures.

Through modelling, a comprehensive surface water study has also been conducted. Modelling through the use of a bigger gauged catchment was adopted because the project area does not have any gauged surface water streams from which reliable data could be obtained and better modelling done. As a result the greater Katongo basin was used for the modelling. On comparison the modelled data easily compared with the observed and the flows showed a correlation of 0.6 which is fairly good.

As was the case for the groundwater survey section, several maps were generated displaying key parameters such as; ▪ Land use cover, ▪ Soil erodibility ▪ Buffer zones around the existing water courses including the rivers, wetlands ▪ Perceived or anticipated potential threat areas for the water resource

As explained in the beginning of this section of the report, some of the key deliverables are well elaborated in volume II of this report. Under volume II, the aspects of surface water and catchment delineation have been well presented and the aspects of the catchment management plan have been captured to detail.

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