A GIS APPROACH FOR FLOOD VULNERABILITY AND ADAPTATION ANALYSIS IN DIEPSLOOT, JOHANNESBURG
ADELINE NGIE (Student No. 201003585)
Department of Geography, Environmental Management and Energy Studies
Supervisors: Prof. H.J. Annegarn
Maryna Storie Gauteng City-Region Observatory, (A collaboration between the University of Johannesburg, the University of the Witwatersrand, Johannesburg and the Gauteng Provincial Government)
A minor dissertation submitted to the Faculty of Science, University of Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Environmental Management.
30 January 2012 Affidavit
TO WHOM IT MAY CONCERN This serves to confirm that I, Adeline NGIE with student number 201003585 and bearer of Cameroonian Passport Number 01138195, enrolled for an MSc in Environmental Management with the Department of Geography, Environmental Management and Energy Studies in the Faculty of Science, herewith declare that my academic work titled: A GIS approach for flood vulnerability and adaptation analysis in Diepsloot, Johannesburg, is in line with the Plagiarism Policy of the University of Johannesburg, with which I am familiar.
I further declare that this work is authentic and original unless clearly indicated otherwise and in such instances full reference to the source is acknowledged and I do not pretend to receive any credit for such acknowledged quotations, and that there is no copyright infringement in my work. I declare that no unethical research practices were used or material gained through dishonesty. I understand that plagiarism is a serious offence and that should I contravene the Plagiarism Policy notwithstanding signing this affidavit, I may be found guilty of a serious criminal offence (perjury) that would amongst other consequences compel the University to inform all other tertiary institutions of the offence and to issue a corresponding certificate of reprehensible academic conduct to whoever request such a certificate from the institution. Signed at Johannesburg Date:
Signature______A. Ngie
STAMP COMMISSIONER OF OATHS Affidavit certified by a Commissioner of Oaths This affidavit conforms with the requirements of the JUSTICES OF THE PEASE AND COMMISSIONERS OF OATHS ACT 16 OF 1963 and the applicable Regulations published in the GG GNR 1258 of 21 July 1972; GN 903 of 10 July 1998; GN 109 of 2 February 2001 as amended.
i Abstract
The 2010/2011 floods saw the City of Johannesburg and many other municipalities in South Africa declared disaster ridden due to the number of deaths, homeless citizens and loss of property. Conventional Geographic Information System (GIS) approach is used to map flood vulnerable areas using floodlines while social surveys assess at-risk population through impacts of a hazard. This study then tests the hypothesis that combined approach to identify and map flood vulnerable areas is better than independent approaches, using Diepsloot township as a case study. Starting with aerial photographs as a base layer, ArcGIS 10™ was used to conduct spatial analysis of the flood-prone areas using the 1:50- and 1:100-year floodlines. The results mapped out dwellings vulnerable to flooding along the floodplains only. The survey probed the people’s perceptions, experiences and coping strategies with flooding. Findings from the field survey revealed some key observations, as follows: The perception of 95% of respondents is that flooding is a major environmental challenge in Diepsloot township as confirmed by their experiences; 61% attributed this to construction of dwellings within floodplains; and 71% agreed that how strong a dwelling is in terms of construction materials also determines its vulnerability to flooding. In addition to floodplains, other sections of the settlement were identified through local knowledge as being vulnerable to various types of flooding - fast-flowing water, ponding and slope run-off. Dwellings on hill-slopes and besides storm water drains were identified as vulnerable to flooding. Slope measurements over the area were done using contours which corroborated these further areas of flood vulnerability as both low-lying and high slopes. Due to poor layout of dwellings, vulnerable units could not be counted but the extent was visible in the mapping. Long-term coping strategies and adaptation measures do seem to be in place, without interventions from municipal authorities. The combined approach for flood vulnerability assessment proved successful in creating a practical and affordable means to create a more comprehensive assessment, called for local knowledge engagement in policy development to mitigate flood disaster risk in the Gauteng City- Region.
Keywords: Diepsloot ·floods ·vulnerability ·adaptation ·informal settlements
ii Dedication
This work is dedicated to my son Muluh Dilane-Thierry
who desires to see me on top.
iii Acknowledgments
For the realisation of this work, I am greatly indebted to a host of persons who supported me in one way or the order to make sure the best results were presented. I am extremely thankful to the Almighty for inspiration and strength throughout this programme. Great appreciations go to Professor Harold Annegarn and Maryna Storie my supervisor and co- supervisor respectively for the endless consultation meetings on academic and technical guidance. They took the pains of always reading through the draft write-ups and giving insightful comments.
Friendly and technical support from the management and specifically Chris Wray at Gauteng City-Region Observatory (GCRO) through software and hardware used for this study is acknowledged, as are Dingaan Mahlangu of SRK for providing floodline data for Diepsloot and technical guidance; and Coleen de Villiers of the South African Weather Service for providing daily rainfall data over Diepsloot for a 50-year period.
Residents of Diepsloot township especially the friendly respondents with whom we shared insights on their experiences and perceptions on reducing flood vulnerability not forgetting members of the field team, especially Richard Thaba, with whom over three weeks we took out our classroom friendship to experiencing the physical environment. You rock! Jaclyn Smith at Statkon is acknowledged for her assistance with statistical analysis.
Management and staff at the Southern Mapping Company (SMC) (Pty) Ltd and Southern Mapping Geospatial (SMG) for the opportunity to be exposed into the geospatial world during which some experience and insight were gained for this study. They also provided spatial data with the authorisation of the Corporate GIS unit of the City of Johannesburg.
Friends and staff of the department of Geography, Environmental management and Energy Studies for academic support are not left out for acknowledgement.
My heartfelt gratitude go with my parents and siblings for continual support and encouragement which drove me to the end. My supportive friends who were there for me are also appreciated heartily.
This work was supported in part through financial contributions from the University of Johannesburg grant to the Sustainable Energy Technology and Research (SeTAR) Centre. I acknowledge financial support from the Faculty of Science for a Merit Bursary and a Top- up Bursary. The generosity of GeoTerraImage (Pty) Ltd in providing a bursary, in support of studies in applications of GIS and remote sensing is appreciated.
iv Table of Contents
Affidavit ...... i Abstract ...... ii Dedication ...... iii Acknowledgments ...... iv List of Figures...... viii List of Tables...... x
1. Introduction 1 1.1. Background ...... 1 1.2. Problem statement ...... 5 1.3. Hypothesis and objectives...... 7 1.4. Rationale for choosing the study area...... 8
2. Flood risk management in South africa 10 2.1. Legal framework...... 11 2.2. Some definitions of floods ...... 12 2.3. Risk in the context of disasters...... 13 2.4. Hazard...... 15 2.5. Resilience or Capacity ...... 16 2.6. Vulnerability in disaster management ...... 16 2.6.1 Flood vulnerability...... 19 2.6.2 Mapping flood vulnerability...... 21 2.7. Methodological approaches in flood disaster risk reduction in South Africa...23
3. Methodology 27 3.1. Overall study design ...... 27 3.2. Study area...... 28 3.2.1 Climate and Rainfall ...... 29 3.2.2 Hydrology...... 32 3.2.3 Geology and soils ...... 34 3.3. Demographics...... 34 3.4. Research methodology...... 35 3.5. GIS conventional floodline mapping...... 36 3.5.1 Acquisition of base maps ...... 36 3.5.2 GIS mapping procedures to generate floodlines...... 36 3.5.3 Mapping flood vulnerability...... 37
v 3.6. Survey of local knowledge on flooding in Diepsloot township ...... 37 3.6.1 Structured household interviews using questionnaires ...... 37 3.6.2 Pilot study...... 39 3.6.3 Administration of questionnaires through households ...... 39 3.6.4 Data analysis from questionnaires ...... 40 3.6.5 Field observations and limitations...... 40 3.7. Classification of housing structures in Diepsloot township...... 41 3.7.1 Data generation for housing structure...... 42 3.7.2 Analysis of data on housing structure...... 42 3.8. Combined local knowledge and physical mapping approach ...... 43
4. Results 44 4.1. Socio-demographic characteristics of respondents in Diepsloot township...... 44 4.2. Mapping flood vulnerability using the floodlines ...... 45 4.3. Local knowledge on flood vulnerability...... 46 4.3.1 Causes of floods within the Diepsloot township ...... 47 4.3.2 Coping strategies ...... 49 4.3.3 Flood impacts in Diepsloot township ...... 53 4.3.4 Evaluate resilience and adaptation...... 55 4.3.5 Other hazard management aspects from local knowledge...... 57 4.4. Results on housing structures and vulnerability to flooding...... 58 4.5. Combined approach for flood vulnerability assessment...... 60
5. Discussion 63 5.1. Flood vulnerability in Diepsloot township...... 63 5.2. GIS hydrological floodline mapping ...... 64 5.2.1 Flood vulnerability mapping using the 1:50-year floodline in Diepsloot township ...... 64 5.2.2 Flood vulnerability mapping using the 1:100-year floodline in Diepsloot township ...... 64 5.2.3 Limitations to mapping ...... 65 5.3. Local knowledge on flood vulnerability...... 65 5.3.1 Causes of floods or flood vulnerability in Diepsloot township...... 66 5.3.2 Coping strategies to floods in Diepsloot township...... 73 5.3.3 Impacts of floods on the households in Diepsloot township...... 75 5.3.4 Flood resilience and adaptation in Diepsloot township ...... 76 5.4. Housing structure and flood vulnerability ...... 78 5.5. Combined approach for flood vulnerability assessment...... 80 5.6. Evaluation of the combined approach to flood vulnerability assessment...... 80
vi 6. Conclusion and Recommendations 83 6.1. Conclusion...... 83 6.2. Recommendations ...... 85
References 87
Annexures 93 Appendix A: Survey on Flood Vulnerability Directed to Households within Diepsloot Settlement Area in the City of Johannesburg - Gauteng Province...... 93 Appendix B: Floodlines...... 102
vii List of Figures
Figure 1: Comparison of flood impacts (death toll) and human development [Adapted from Peduzzi et al., 2005]...... 19 Figure 2: Impact of urbanisation on runoff quantities [Adapted from Viljoen & Booysen, 2006]...... 23 Figure 3: Study design for this research ...... 27 Figure 4: Map and geographical location of Diepsloot township [Adapted from Google Earth, 2010; CoJ, 2009; AGIS, 2001] ...... 28 Figure 5: Annual summer rainfall (summed from October through March) for Diepsloot [Data from SAWS: 1960-2010]...... 30 Figure 6: Monthly rainfall over Diepsloot [Data from SAWS: 1960-2010]...... 31 Figure 7: Probability of rainfall above monthly thresholds for Diepsloot...... 31 Figure 8: Diepsloot river catchment (Ngie, 2011) (Enlargement of squared site in Figure 9)...... 33 Figure 9: Google earth image illustrating human disturbances along the Diepsloot floodplain [Credit: Google Earth 2010 Image] ...... 33 Figure 10: Relatively flat terrain within the floodplain in Diepsloot (Photo credit: Ngie, 2011)...... 34 Figure 11: Informal housing structures in Diepsloot township (Photo credit: Ngie, 2011) ...... 42 Figure 12: Flood vulnerability mapping using 1:50-year floodline (Ngie, 2011)...... 45 Figure 13: Mapping flood vulnerability in Diepsloot township using a 1:100-year floodline (Ngie, 2011)...... 46 Figure 14: Reasons for households not damaged by floods in Diepsloot township...... 48 Figure 15: Rodent holes through which water floods homes (Photo credit: Ngie, 2011) ...... 49 Figure 16: Comparing flood experience in former area and coping strategies ...... 50 Figure 17: Flood impacts on furniture and dwelling units in Diepsloot township (Photo credit: Ngie, 2011)...... 54 Figure 18: Floor lined with plastic before cement (Photo credit: Ngie, 2011) ...... 56 Figure 19: Flood adaptation measures in Diepsloot township (a) Sandbags to block runoff; (b) Pipes underneath dwelling units; (c) Raise furniture on bricks and tins (Photo credit: Ngie, 2011)...... 56 Figure 20: Other natural hazards plaguing Diepsloot township ranked accordingly ...... 57 Figure 21: Sources to seek aid by flood victims in Diepsloot township ...... 58 Figure 22: Housing types in Diepsloot township (Extract from an aerial photograph of the City of Johannesburg, flown in 2010 by Southern Mapping Company (Pty) Ltd)...... 60 Figure 23: Comparison of predominant wall material and loss of beds and bedding during floods. (Combined = metallic sheets, cardboard, wood etc.) ...... 60
viii Figure 24: GIS derived slope calculations over the Diepsloot township indicating flood prone areas – labelled A to G (discussed further in the text) (Ngie & Storie, 2011) ...... 61 Figure 25: Groundwater seepage and retention within the floodplain from dwelling units in winter (Photo credit: Ngie, 2011)...... 62 Figure 26: Construction within poorly drained areas in Diepsloot township (Photo credit: Ngie, 2011)...... 67 Figure 27: Crossing streams without bridges increases vulnerability of residents in Diepsloot township (Photo credit: Ngie, 2011)...... 69 Figure 28: Johannesburg Roads Agency public notice on the danger of storm water drains in Extension 5 (Photo credit: Ngie, 2011) ...... 70 Figure 29: Waste dumping exacerbates flood vulnerability in Diepsloot township: (a) waste dumping into a storm water drain; (b) waste carried by water runoff from an informal dump across roads and into storm water drains (Photo credit: Ngie, 2011)...... 71 Figure 30: Construction of dwelling units on storm water drains in Diepsloot township (Photo credit: Ngie, 2011)...... 72 Figure 31: Construction of dwellings around storm water drains (Photo credit: Ngie, 2011) ...... 73 Figure 32: Filling stream paths in Diepsloot increases flood vulnerability (Photo: Ngie, 2011)...... 80 Figure 33: 1:50-year floodline for Diepsloot (Mahlangu & Braune, 2010)...... 102 Figure 34: 1:100-year floodline for Diepsloot (Mahlangu & Braune, 2010)...... 102
ix List of Tables
Table 1: Monthly rainfall threshold return frequency for Diepsloot (Data from SAWS) ...... 32 Table 2: Socio-demographic characteristics of respondents...... 44 Table 3: People's perceptions on flood vulnerability ...... 46 Table 4: Flood causes in Diepsloot as identified by households ...... 47 Table 5: Comparing educational levels and flood coping strategies in Diepsloot township ...... 51 Table 6: Flood experience and willingness to move out of Diepsloot township ...... 51 Table 7: Comparison of flood experience in former area and willingness to be evacuated from Diepsloot township ...... 52 Table 8: Cross tabulation on past and present flood experiences within Diepsloot township and willingness to be evacuated ...... 53 Table 9: Items damaged by floods in Diepsloot township and their value ranked by respondents...... 54 Table 10: Housing quality index for Diepsloot township...... 59 Table 11: Comparison between physical floodline mapping and the combined flood vulnerability approach ...... 81
x 1. INTRODUCTION
This chapter introduces the need for flood vulnerability assessment in the Gauteng City-Region through the growing number of devastating flood experiences especially in its informal settlements. It highlights flooding as a global problem ravishing property and human lives as background to the study with some flood types and causes. It presents some flood management solutions which have mainly dwelled with conventional technological measures and social surveys to assess impacts on population. It then leads to the problem being examined by this study from which the aim and specific objectives are stated. The rationale for choosing Diepsloot as a case study is then presented to wrap up this chapter.
1.1. Background
The floods that occurred in 2010/2011 across South Africa saw the City of Johannesburg as well as many other municipalities declared disaster areas due to the number of deaths and loss in property. As designated under Sections 3 and 27 of the National Disaster Management Act (NDMA) of South Africa (Act No. 57 of 2002), a national disaster was declared in eight out of the nine provinces of South Africa as a result of these floods [RSA, 2011]. Gauteng was one of the provinces and the City of Johannesburg Municipality in particular that was affected. According to the Natural Disaster Management Centre (NDMC) more than 14 000 families within these eight provinces were affected to the cost of approximately R1.5 billion and over 74 deaths as a result of the event [Makinana & Magwaza, 2011]. It has furthermore been ascertained that floods causing significant damage occur at least once every two years in some areas around the country, with larger and more extensive floods occurring at least once every 10-15 years. This is evident in the massive floods that occurred in 1974, 1988 and 2000 [Viljoen & Booysen, 2006].
Floods may have a variety of origins, which are classified according to their cause. For instance, some may be meteorologically caused through weather phenomena and events that are associated with precipitation. This occurs when more precipitation and associated runoff is delivered to the drainage basin than what can be readily absorbed or stored within the basin.
The failure of dam walls to do required function of holding water as a result of heavy rains or by human acts (of war or sabotage) also cause flooding. It could also be as a result of
1 inadequate maintenance and upkeep or structural failure of materials used in construction. It usually records destruction over extended areas, on infrastructure and humankind.
Other causes of flooding may be inappropriate or inadequate storm water infrastructure design or maintenance, or development which decreases infiltration and increases runoff levels through hardening of surfaces in built-up areas. Although precipitation in general may cause floods and aggravates the other causes mentioned above, heavy rainfall is one of the primary causes of inland floods in the built environment and this is the focus of this research. Heavy rains would “…vary from the semi predictable seasonal rains over wide geographic areas, which give rise to the annual monsoonal floods in tropical areas, to almost random convectional storms giving rise to flash floods over small basins” [Smith, 2004: 264]. The magnitude (determined by the depth and velocity of water), speed of onset and duration of the flood are influenced by factors such as topography, vegetation and soils, storm water channel or river alteration and infiltration rates which are related to land use and urbanisation. In addition to these factors, there is great concern regarding the placement of built-up structures and especially informal housing in flood-prone areas.
Urbanisation therefore worsens floods by reducing the permeability of ground surfaces and increasing runoff rates [Miller, 1997; Parker, 2000]. Not only have floods been seen as being caused by climate change but also by other environmental processes such as constrained floodplains by dwellings, illegally dumped waste, earthworks, embankments, concrete and other infrastructure which may alter floodplains [Smith, 2004; Wisner et al., 2004].
Floods are considered as one of the most endangering source of disaster risk [Alexander, 1997; Parker, 2000; Sharma & Priya, 2001; van der Sande et al., 2003; Smith, 2004; Wisner et al., 2004; Jonkman & Vrijling, 2008] both at global and local levels. Scheuren et al. [2008: p. x] reported the leading causes of disasters and economic damage being attributed to hydro-meteorological disasters in 2007. Flooding affects approximately 520 million people and their livelihoods, claiming about 25 000 lives worldwide annually [WMO-UNESCO, 2007]. These disasters are becoming increasingly unpredictable, thereby increasing the potential impact and severity of consequences to humans and their property and livelihoods.
2 Flood return periods are commonly expressed in numerical values of e.g. 20-, 50-, 100- or 200-years. This is based on detailed site surveys and river cross-section analysis (e.g. in the case of 20- and 50-year return periods in particular), or uses larger interval contour data, in the case of designing 100-year or 200-year indicative floodlines. These recurrence periods indicate the probability of a specific level to be reached, within a particular year. This means in practical terms that in the case of a 20-year flood, the probability is 100% that the specific level of inundation indicated by the flood line could be reached during any particular year. Similarly, for a 100-year indicative floodline, there is a probability that the specified level could be reached once in a 100 years [Alexander, 1997]. However, this does not mean that there may not be more than one such occurrence within a given years - there are situations where 100-year floods have been experienced almost annually in Bangladesh and China [Wisner et al., 2004]. This relates to the unpredictable nature of climate and meteorological factors, which are exacerbated by climate change.
Flooding may present itself in different forms, which range from regular water logging of ground after rainfall through more severe but relatively predictable seasonal flooding to catastrophic flood events that overwhelm coping capacities of local communities and authorities and constitute disasters [Few, 2003]. Wisner et al. [2004] noted that there is no clear distinction between mild and severe forms of flooding – the same event can have differential effects on neighbourhoods and even households depending on their vulnerability. With the frequency and variability of flood events changing because of urbanisation, coupled with rapid urban population growth and potential climate change [IPCC, 2001; WDR, 2010], the number of people vulnerable to devastating floods worldwide is expected to rise. This is exacerbated when considering that vulnerable and poor communities may settle on marginalised or potentially dangerous land, due to their inability to afford safe locations. Disaster risk reduction actions, in a dynamic world, will therefore increasingly be required to build the necessary capacity to cope with floods, both within governing structures and local communities.
In a rapidly densifying urban environment, space is at a premium and there are often conflicts between the need to provide infrastructure versus the need to maintain storm water retention zones (open spaces). Although these structures are necessary to formalise water runoff and ensure formal structure safety, it is not the only solution to urban storm water management. Often, these measures alone are considered ineffective because, among other reasons, they are likely to ignore local knowledge about flood hazards, as well as
3 socioeconomic inequalities as main determinants of flood vulnerability. Engineering solutions associated with this conventional approach often create a sense of false security to communities in hazard prone-areas [Mileti, 1999; van Bladeren et al., 2007] thereby lulling them into inaction.
In addition, local flood coping mechanisms, such as creation of outlets on dwelling units, raising dwelling units and higher structures upon which household objects can be placed have been implemented in Diepsloot township (an informal settlement to the north of Johannesburg). These mechanisms have actually been employed to save property as well as lives and others can be disrupted or destroyed. It would be wrong, however, to argue that local coping mechanisms have been in ecological balance over the years. Such local coping strategies have become adaptive to an extent that new developments within informal areas employ them. This has permitted fairly large populations to exploit fragile environments in an unsustainable manner. For instance, some residents of Diepsloot township have practiced some of the above methods and so become adapted to them. These residents are proud to construct their dwellings on wetlands!
In the drive towards greening and sustainable livelihoods, which are aimed at, enabling society to adapt to the changes that they are faced with, climate change is on the top of the list. When reviewing the predicted effects of climate change in South Africa, the first effects will be a moderate increase in temperature, with possible dramatic shifts in weather patterns and storm occurrences. It is predicted that there will be reduced average rainfall for the summer rainfall areas with both an increase in the number and impact of drought and storms [Watson et al., 1997; GCCOLP, 2011]. Natural hazards such as floods will also increase, both due to weather changes and due to the increase in population densities in flood plains. In addition to this, flood plains that may have been previously accepted to provide safe building lines (e.g. 50-year flood lines or 100-year indicative flood lines) may not be adequate any more to ensure safety. It is expected that long-term ponding of water in low-lying areas may also increase. Thus, within the context of climate change, it appears that floods are not only set to become increasingly unpredictable, but also more severe, depending on its origin, often starting rapidly and potentially occurring in areas that have less recent experience of large scale flooding.
In reducing vulnerability past studies have varied from the physical and social sciences. Whereas physical science approaches have ranged from real-time observations with
4 extensive multi-sensor networks, more precise mapping capabilities using remote sensing and GIS, quicker hydrological and meteorological models, and increasing forecast lead times on their own, have not reduced losses [Montz & Gruntfest, 2002]. On the other hand, social science approaches using socio-economic and political surveys through individuals and communities independent of physical sciences have not also reduced losses [Pelling, 1997; 1998]. There is a need for greater emphasis on a combined and trans-disciplinary approach that will reduce vulnerability of communities in sustainable ways compatible with long-term economic and social goals. Therefore, the relationship between hydrometeorology and social science is seen as critical in advancing the ability of humanity to cope with floods. This study implements this approach to identify households being exposed to flooding in Diepsloot township.
1.2. Problem statement
Population growth, urban development processes and pressures, trends in land occupancy, increase in poverty levels, inadequate organisational systems and pressures on natural resources or environments have continuously increased vulnerability of populations. One of the natural hazards facing informal settlements is that of flooding, a hazard that is anticipated to increase in severity as a consequence of climate change.
Population growth in the city of Johannesburg has led to human settlements on flood plains. An example of this is the Diepsloot township. The inhabitants of this settlement have arrived mostly through in-migration in search of better life. The indiscriminate choice for settlement sites by the poor sometimes exposes them to hazards that could be avoided through proper town planning. The settlements themselves may induce changes in watersheds which are presumably blamed for the increase in flood damage news [Varis, 2005]. The concentration of population in such areas often bring with it associated challenges such as sustainability of ecosystem services that threaten their resilience [Van Huyssteen et al., 2009].
In a bid to manage these challenges, the Gauteng provincial office of Agriculture and Rural Development (GDARD) came up with a Climate Change Response Strategy and Action Plan [GDARD, 2011]. It emphasises the integrative methodological approach for disasters to mitigate their impacts and develop adaptive measures within such disaster prone communities. The Gauteng City-Region Observatory (GCRO- a collaboration between the University of Johannesburg, the University of the Witwatersrand, Johannesburg and the
5 Gauteng Provincial Government) is one of the stakeholders charged with the above responsibility which among others include the mapping of these areas and investigating peoples’ perceptions on vulnerability, mitigation and adaptation capacity [GDARD, 2011:47].
Diepsloot township developed from government relocation of people from Zevenfontein and the banks of the Jukskei in Alexandra in 1995 and 2001 respectively in a bid to cater for its populace through housing provision. This planned settlement gradually became unplanned as other people moved in who were not qualified for subsidised government housing. They had to put up their own housing structures (shacks). Some of these structures especially in Diepsloot West have been noted to be located within the 1:50- and 1:100-year floodlines. Within these zones, people and property are exposed to flood damages every year [Mahlangu & Braune, 2010].
One of the response measures in flood management has always been relocating the population to other areas. This shall not continue forever since land is limited for onward development and especially in the case of Diepsloot township on two reasons. Firstly, Diepsloot is a border region between two municipalities (City of Tshwane and City of Johannesburg) where development cannot proceed to the north. The south, east and west are limited by major highways. Secondly, neighbouring areas to this settlement comprise of high-income neighbourhoods, which have increased the cost of land above the reach of the low-income populace in Diepsloot township. These high-income neighbourhoods including Dainfern, Fourways and Midrand, comprise mostly of privately owned land which limits government intervention. Land expansion to accommodate growing population in Diepsloot township has therefore been declared a problem by the provincial Department of Development Planning and Urban Management [DPUM, 2007].
This limited land is faced with development pressures which are changing the natural functionality [Van Huyssteen et al., 2009]. Hydrological features such as infiltration rates and runoff levels have been reduced and increased respectively. This has contributed to increase volumes of water flowing through its course (rivers) thereby causing inundation into settlement structures when it rains.
While it should also be noted that low adaptive measures increase vulnerability of the population, inequalities and divergence in living standards further exacerbates the situation
6 within the Diepsloot township. This area is characterised by blocked drains, poorly drained areas which are poorly maintained. The settlement structures comprise mainly low income government-subsidized houses through the Reconstruction Development Programme (RDP) and shacks constructed with old sheets of metal [CoJ, 2006]. These structures being constructed in such low-lying flood prone areas are supposed to be elevated to a particular level to avoid flood waters. For instance, no structure within the 1:50-year floodline and all floors to be raised above the 1:100-year floodline [Mahlangu & Braune, 2010].
Adaptation and mitigation strategies are necessary to increase the communities’ preparedness and resilience in the light of disaster impacts on humankind and its created environment. These include improvement in flood mitigation on infrastructure; better early-warning systems and rescue services; sustained behavioural change; a change in housing design and improvement of sanitation infrastructure; as well as sustained public health surveillance.
Conventional approaches often provide conventional engineering solutions (e.g. delineation of floodlines, assigning infiltration zones and building of dams, levees and attenuation structures) that focus mainly on the physical event through engineered processes [Cardona, 2003; Varis, 2005; Zevenbergen et al., 2008]. These interventions are more often than not costly and require space to be allocated. It has become vital to understand the human behaviour, new technologies, indigenous knowledge and social livelihoods to be able to put effective adaptation and mitigation strategies in place.
In order to understand household flood vulnerability, which is a complex task that should transcend conventional approaches that emphasize physical processes, this research argues for the incorporation of local knowledge into the flood management processes and planning. It therefore hypothesises that a combined approach to flood vulnerability assessment using conventional Geographic Information Systems (GIS) floodline mapping, and social evaluation of the perceptions and coping mechanisms of vulnerable population, provides a better overall assessment than either of the two methods used separately.
1.3. Hypothesis and objectives
Hypothesis: A combined social-scientific approach leads to a more robust assessment of flood vulnerability in informal settlements than traditional approaches that utilise either social or physical assessment methods independently. The study seeks to test to what
7 extent the combined approach to flood vulnerability assessment is better in identifying at- risk areas within informal communities of the Gauteng City-Region. This region is an integrated cluster of cities, towns and urban nodes that together make up the economic heartland of South Africa situated around the Gauteng province (to the north-west is the town of Rustenburg; south is Sasolburg; east are towns as Witbank, Middleburg and Secunda; and north east is a swathe of semi-urban settlements)1.
The specific objectives for this study are: To utilise conventional GIS approaches (floodlines) for physical flood vulnerability mapping in Diepsloot township as a case study.
To assess the knowledge of inhabitants of this mixed formal and informal settlement (Diepsloot) about flood vulnerability, causes, coping strategies and impacts.
To evaluate housing structure and their resilience with respect to construction material.
To generate a refined flood vulnerability map of the study area using the combined results of the local knowledge survey and the physical GIS mapping.
To perform an assessment of the refined vulnerability mapping methodology for use in flood vulnerability and risk reduction strategies for Gauteng Province.
1.4. Rationale for choosing the study area
Even though Johannesburg lies on the continental divide away from the coast and major rivers, areas of the city are subject to periodic flooding (as happened in December 2010 and January 2011). Higher frequencies of severe storm events are predicted by global climate change models, possibly aggravating the vulnerability of low lying areas to flood hazards. Urban development with increasing fractions of the surface area covered by hard paving accentuates flash floods during severe storms. Johannesburg contains numerous informal settlements which by their nature have bypassed normal planning procedures. Several of these are located in areas along stream banks and seasonal wetlands, making them highly vulnerable to flooding.
1 http://www.gcro.ac.za/about-gcr/overview accessed 18/07/2012.
8 The Diepsloot township is situated along the banks of the Jukskei River (a tributary of the Crocodile River) is a typical example of such a vulnerable settlement. It has a large cluster of informal settlement structures, mixed with some formal structures. It is a settlement developed at the border of two major municipalities (City of Johannesburg and City of Tshwane) in South Africa. This area (Diepsloot township) falls within ward 95 which can be prioritised as part of the GCRO’s ‘50 Priority Wards’ project that is being done for the Gauteng Planning Commission.
Extensive data sets are available to support Diepsloot township as a case study for this research; The floodlines for Diepsloot have been assessed and data available from the Steffen Robertson and Kirsten (SRK) Consulting. Local knowledge about the development of this settlement is available from the people and their experiences with floods. Rainfall data are available from the South African Weather Service. There are aerial photographs and GIS data (river systems, land use and others) from City of Johannesburg and GCRO.
9 2. FLOOD RISK MANAGEMENT IN SOUTH AFRICA
After the introduction of this study, there was need to contextualise by presenting a review of recent literature in the field of flooding through selected global and South African examples. The review opens up with recent flood events (2010/2011 floods in South Africa) to show relevance of this study and subsequently presents the disaster management legal framework for the country. The chapter presents keywords linked to disaster management and their relation to this study. It then unravels various methodological approaches of flooding in South Africa and the need for another dimension.
In recent history flood studies in South Africa have increased even though it might be considered strange since the country is within the semi-arid areas of the world. The challenge has been the flood events that hit the country at various geographical scales. Through preliminary research some studies in the South African context have been identified that will be dealt with in this chapter. Some insight shall also be drawn from international experiences especially in the situation of flood-prone countries like Pakistan, Bangladesh and neighbouring Mozambique being hit by flood disasters on almost an annual basis.
This literature will then be narrowed down to the City of Johannesburg in particular, as the city has been struggling with some severe storm events over recent times. These flood events have been mainly caused by flash floods, failure or absence of storm water drains and inundation of rivers, leading to loss of lives and damage for both individuals and the public sector. The recent floods of 2010/2011 hit the country and private sectors hard, with 74 lives lost and damage to property and infrastructure worth over R1.5 billion reported [Makinana & Magwaza, 2011]. There is therefore need for more studies on floods in South Africa especially at the level of spatial-temporal scales as was recommended by Van Huyssteen et al. [2009]. Van Huyssteen et al. examined the state of storm events within the City of Johannesburg and the losses incurred on property and lives. They concluded their study with recommendations to effectively manage such storm events in order to minimise risk and vulnerability.
10 2.1. Legal framework
Disasters are managed in South Africa under the legal umbrella of the National Disaster Management Act (NDMA) (Act No 57 of 2002). The NDMA required a National Disaster Management Framework (NDMF) to be developed, which was subsequently promulgated in 2005. The Act is currently under review, which allows for changes to be made in order to ensure that it addresses elements that may not have been included in the 2002 version [Bruwer2, 2011; Personal Communication]. These instruments are intended to facilitate transversal engagement in disaster risk reduction by different stakeholders. The framework gives explicit emphasis to risk and vulnerability assessments and reduction, especially in vulnerable societies. It further emphasises cooperative governance as a priority in meeting disaster management objectives through disaster management plans at provincial and municipal levels.
The framework addresses the need for consistency across multiple interest groups and gives priority to developmental measures, disaster prevention and mitigation. Four key performance areas of the framework could be summarised as follows: Institutional arrangements Disaster risk assessment and monitoring Disaster risk reduction and response Recovery and rehabilitation.
There are three enablers defined with which the above should be achieved: Information management and communication Education, training, public awareness and research Funding arrangements.
The SAWS Act No. 8 of 2001, Section 4(3), declares that only the SAWS is allowed to issue severe weather warnings in South Africa. Furthermore, the Municipal Systems Act No. 32 of 2000 requires an Integrated Development Plan (IDP) with Strategic Development Plans (SDP) to be drawn up every five years, with an annual review in consultation with local communities. This lays the ground for local knowledge incorporation into disaster management in South Africa.
2 Ané Bruwer Executive Manager: Disaster Management Legislation, Policy and Compliance Management National Disaster Management Centre, National Department of Cooperative Governance.
11 Furthermore the National Building Regulations and Building Standards Act No. 103 of 1977 stipulate development within the 1:50-year floodline area should require safety considerations and understanding of the underlying natural stream flow process. This is further reiterated by the Town Planning and Townships Ordinance Regulation 44(3). It emphasises on buffering flood areas up to 32 metres from the centre of a stream in cases where the 1:50-year floodline is less than 62 metres wide in total [CSIR, 2005; van Bladeren et al., 2007]. This is evident in planned communities and scarcely respected within unplanned ones. Paradigm shift has been ensured by this legal framework from reactive to proactive activities. Conducting a risk and vulnerability analysis for land use planning is vital - it would be a tool to identify risks and vulnerabilities at an early stage to ensure the promotion of sound infrastructure development and land use [Rauken & Kelman, 2010]. However, lack of proper implementation of such risk assessment exposes communities to many natural disasters, especially floods.
The NDMA mandates local authorities to provide proactive disaster mitigation strategies including early warning systems. The challenge of capacity and budget handicaps municipalities to effect this responsibility. The NDMC is only mandated to coordinate, not to provide skills and services to local disaster managers [Mkwananzi & Pegram, 2004]. However, in order to achieve optimum levels, a risk reduction plan for unplanned residential occupation of flood prone areas should be developed where social, political and economic aspects would be integrated. Most local authorities in South Africa have developed design standards or plans based on judgement and experience, rather than on optimisation criteria [Sinclair & Pegram, 2004].
2.2. Some definitions of floods
The United Nations International Strategy for Disaster Reduction (UNISDR) and the Centre for Research on the Epidemiology of Disasters (CRED) have jointly come up with a definition to floods as being a hydro-meteorological situation where high river/stream flow over tops its banks in any part of its course, covering land that is not normally covered with water [ISDR, 2010]. In other words, it shall be simply put as a geographic condition occurring when water within a stream/river overflows its banks that are the natural confines, or even artificial confines like concrete embankments, into land that was not previously covered by water. It could also be as a result of water accumulation within a drainage system over a low-lying area [Sims et al., 2009]. In addition Ramlal and Baban
12 [2008:1131] describe it “…as a mass of water, which produces runoff on land that is not normally covered by water.” Alternatively they also describe it “…as a fair high flow which overburdens the natural channel that is being provided for the runoff”. This means areas away from water bodies can still be exposed to flooding depending on the relief leading to prolonged damages. Floods in Mozambique during the January-March of 2000, cover vast areas, some up to 20 km away from the normal river channel were under water for several weeks (Christie & Hanlon, 2001).
Floods have been classified as the most common of disastrous acts of nature among all catastrophes leading to economic losses and deaths [Sharma & Priya, 2001; Jonkman & Vrijling, 2008]. Its damage in South Africa has been enormous, for example in the above mentioned 2010/2011 floods involving loss of lives, property and other damages associated with such scenarios.
2.3. Risk in the context of disasters
The ISDR [2004] describes risk as the probability and the amount of harmful consequences or expected losses resulting from interactions between natural or human induced hazards and vulnerable conditions. It can also be looked upon as being exposed to a chance of loss or damage from a hazard. Mathematically, it could be expressed as follows: VH R ReCor where R is the Risk, H is hazard, Re is Resilience or C which is the capacity).
Risk in the past was used by some researchers as synonymous to vulnerability. As explained by Cardona [2003], in the attempt to answer the question of Vulnerability to what? It should be realised that hazard and vulnerability are concomitant leading to risk. This implies that, if there is no hazard, then it is not feasible to be vulnerable from the perspective of potential damage or loss due to the occurrence of an event. On the other hand, there is not a hazard situation for an element or system if it is not exposed or vulnerable to the potential phenomenon.
In order to completely manage a risk, there are some distinct phases through which policies could be developed and these include: Risk identification which ranges from perceptions,
13 social representation and objective assessment wherein mapping flood vulnerability is an objective assessment for risk identification within the Diepsloot township.
Risk reduction or prevention or mitigation into which vulnerability reduction also makes a contribution. When there is a forecast of the possibility that a dangerous phenomenon or event will occur, it implies that exposed or fragile elements are predisposed or susceptible to being affected. However, the reduction of disasters is becoming more and more difficult challenge to researchers just like their impacts as a result of development styles.
Disaster management which involves response and recovery where there is risk transfer involving insurance and financial protection. This is mostly not considered in developing countries, since the population hardly thinks of insuring their homes. In the case of the Diepsloot township, where we shall be involved with informal dwellers, insurance will not be considered. According to Halloway [2003:33-34], disaster management is linked by key components that include ‘prevention, mitigation, preparedness, response, and recovery/rehabilitation’: prevention would provide an outright avoidance of the adverse impacts; mitigation would be involve with the ongoing structural and non-structural measures undertaken to limit the adverse impacts of natural hazards; preparedness would be the activities and measures to effective response in an emergency and its impacts (timely and effective warnings and temporal removal of people and property from a threatening location); response would be assistance or intervention during or immediately after a disaster to meet life preservation; and recovery/rehabilitation would be the decisions or actions taken after a disaster with a view of restoring living conditions of the stricken community while encouraging and facilitating adjustments to reduce disaster risk.
Flood risk is the combination of the probability of a flood event and of the potential adverse consequences to human health, the environment, cultural heritage and economic activity associated with a flood event [van Alphen et al., 2009]. Flood risks can also be viewed as processes that result from a combination of flood hazards and societal vulnerabilities, hazard modification and amplification, vulnerability enhancement due to various social processes and factors [WMO-UNESCO, 2007]. The first essentials in reducing the risk and consequential damage of any type of natural disaster are to assess, predict and warn about the natural hazards and the vulnerability of the communities to them [Hunt, 2002]. Therefore, an understanding of this risk and working towards the
14 modification of risk-generating processes in a holistic approach would reduce its negative impacts on humans and property.
2.4. Hazard
Erickson [1999] defines hazard to include the level of harm or the injury itself. Hazard in the context of disaster management is referred to “a source of potential harm or injury, or an existing situation with a potential to cause loss” [SACN, 2009:26], that may occur suddenly or have a slow onset [GCS, undated]. This double meaning often results in the confusion of ‘cause’ and ‘effect’. However, the word ‘hazard’ always denotes a possibility or potential of the severity of an effect and in the context of this research refers to the ‘cause’.
According to the ISDR [2004], hazard is defined as a potentially damaging event, phenomenon and/or human activity, which may cause the loss of life or injury, property damage, social and economic disruption or environmental degradation. In this case we are considering floods to be the hazard to which humans and property in Diepsloot township are exposed to. Hewitt [1997] argues that ‘hazard’ refers to a potential for damage that exists only in the presence of a vulnerable community. This view embodies the idea that by altering the vulnerability of exposed populations, the effects of hazardous events may be reduced. Such ideas are well established within the academic literature, but have rarely been incorporated into flood management policy.
A hazard would be described as a disaster only when the losses exceed the capacity of the population to support or resist them or when the effects impede easy recovery. According to the South African Disaster Management Act [RSA, 2002:5], “…disaster is a sudden or progressive, localised or widespread, natural or human-induced occurrence which can threaten to cause or cause injury, disease or death (living things); damage to property, infrastructure or the environment (nonliving things); or disruption to the life of a community. It also adds that …the occurrence is of a magnitude that exceeds the ability of those affected by the disaster to cope with its effects using only their own resources.” for instance the famous Mozambican floods of 2000 had an estimated 700 lives were lost; 45 000 people were rescued from floodwaters; an estimated 500 000 people were displaced from their homes; and more than $400 million of property was damaged by the floodwaters (Christie & Hanlon, 2001).
15 2.5. Resilience or Capacity
Resilience is simply defined as the aspect of returning/springing back to the original situation after disturbance. In this case, considered as what the populace does after a given flood event to resettle and carry on with their former daily activities. Are they relocated to other sites or return to same area and reconstruct new dwellings under same conditions? Mozambique’s own experience in dealing with complex emergencies during its history of encounters with flood disasters has provided it with a degree of resilience as in establishing an institutional base for disaster response (Ziel, 2002). Resilience which involves recovery from the impacts of a disaster is very important especially knowledge in accessing emergency shelters for vulnerable populations. Capacity building and information sharing can be identified as key aspects in developing resilience within a population for natural disasters (Gall, 2004). The World Reduction Campaign for 2010/2011 is themed as “Making Cities Resilient” wherein it has been discovered that global cities, including City of Johannesburg, are faced with challenges that lead to increase vulnerability as a result of crowded settlements, unsafe construction and lack of urban planning and destruction of natural buffers like wetlands [ISDR, 2010]. It should be noted that the City of Durban is a part of this campaign already through which climate change considerations have be institutionally integrated through an ongoing process of building local capacity and knowledge on its impacts like floods [Roberts, 2008].
2.6. Vulnerability in disaster management
Vulnerability is derived from the adjective ‘vulnerable’ that can simply be described as being susceptible to attack. Things that can be susceptible to attack include living and nonliving things. Hence, vulnerability is a state of being susceptible to attack. Within this context we shall be looking at the susceptibility of humankind and its settlement structures (households) to various flood depths. Some extreme and often permanent conditions exist that make livelihood activities extremely fragile for certain social groups.
It has also been defined as a human condition or process resulting from physical, social, economic and environmental factors which determine the likelihood and scale of damage from the impact of a given hazard [Blaikie, 2004:13]. It represents therefore physical, economics, political or social susceptibility or predisposition of a community to damage in the event of a destabilising phenomenon of natural or anthropogenic origin. Vulnerability
16 is strongly linked to the complex make-up of society, including class, gender and age, past loss and misfortune and susceptibility to future losses. From the risk formula above, we could deduce the formula for vulnerability as: ReCorR V H where V is vulnerability, R is risk, Re is resilience (or C which is the capacity), and H is hazard.
This concept has been widely used across disciplines involved with different dimensions ranging from social sciences, natural sciences to applied sciences. In social sciences, it is used to refer to disadvantaged conditions for instance elderly, children and women described as vulnerable group. In certain research works within this discipline, it is considered that social, economic, cultural and educational aspects are in most cases, the cause of potential physical damage also referred to as physical vulnerability [Cannon, 1994; Bankoff, 2001]. In this light we might be tempted to say vulnerability is a condition that is constructed, accumulates and remains over time and is closely linked to social aspects and level of development of the community. The focus in this study would also be on the physical which essentially relates to the degree of exposure and fragility of the exposed elements (settlement structures) to the action of floods.
In the natural sciences, it has been looked at from the idea that they occur ‘naturally’ and there is nothing to be done to avoid them. No doubt some politicians or decision makers have taken shelter in this school of thought to console affected persons by a disaster. This further favours the idea that disasters are exclusively linked to physical phenomena which generate the events. The greater challenge for natural scientists has been to use technological advancement and geophysical, hydrological and meteorological instrumentation to predict with certainty and precision the occurrence of the future event [Cardona, 2003]. In this case, the geophysical landscape shall be closely considered as well as the rainfall of the Diepsloot area in order to explain physical vulnerability of the settlement structures.
Applied sciences provide new elements for estimating the damages and losses due to the disaster events. There is emphasis that damage is not only due to the severity of the natural phenomenon, but also to the fragility or vulnerability of the exposed elements [Cardona, 2003]. This implies that there should be some level of security and trustworthiness of
17 infrastructure or system in the face of a disaster. This calls for different experts in a complete management programme for disaster, ranging from architects, town planners, economists, to engineers especially in considering standards in constructing buildings and infrastructure. Then comes a need for an interdisciplinary approach in handling flood vulnerability studies.
This diversity could be summarised as follows: Vulnerability of various social groups within a community/society; and the role of social network groups. It could also be viewed as the position and status in society which is directly linked to wealth, health, race and gender. Vulnerability of various economic sectors involved like the housing market in flood areas as well as many other businesses since road network would be affected. Vulnerability depending on environmental services and fragility or geographical proximity to a hazard or potential hazard like locating below a floodline. Vulnerability depending on technology wherein some structures would be more susceptible than others in a given hazard. This shall be linked to various housing structures and road networks in Diepsloot. There is also vulnerability linked to the effectiveness and failure of institutional structures where assigned roles are not undertaken. This vulnerability may further be compounded by self and social protection. Wherein self protection would be individual capacity to protect oneself from the harm like having access to information or materials needed while social would be extent of assistance and support from others like technical or expert information [Mqguba & Vogel, 2004].
The literature on vulnerability stresses the primacy of public risk perception and understanding in mediating the success of attempts to increase hazard resistance and resilience. It places emphasis on the need to tackle root causes of community vulnerability [Wisner et al., 2004; Bankoff, 2001]. Vulnerability to hazard is embodied in the concepts of resistance and resilience of exposed populations. The greater the ability at individual, community or societal level to resist the negative effects associated with a hazardous event and the greater the capacity for long-term recovery, the less vulnerable such populations are likely to be [Morrow, 1999].
Such rigid and deterministic definitions of vulnerability do not adequately address the link between risk perception and mitigation, or between vulnerability and adaptation through
18 local coping practices, such as social and family support networks. Moreover, the categories used to define vulnerability have not been adequately explored, aside from asserting that sensitivity towards issues such as gender, ethnicity or ability of the elderly to cope is important, thus giving rise to a stereotyped and unenlightening view of risk and capacity for hazard response. However, this research shall focus more on physical vulnerability which is linked to proximity to the hazard being floodlines within the flood plains. It shall also probe vulnerability to floods from the residents of the case study in order to ascertain adaptation and combining these two approaches to identify comprehensively at-risk areas.
2.6.1 Flood vulnerability
From the definitions of floods and vulnerability, we shall coin flood vulnerability to be a measure of risk combined with the level of social and economic ability to cope with a flood event. This refers to the personal or group characteristics in terms of their capacity to anticipate and cope with the impact of floods [Scoones, 1998]. In this light, researchers have defined flood vulnerability as the degree to which the different social groups or classes within a society are differentially at risk, both in terms of probability of occurrence of an extreme flood event and help different classes to recover [Cardona, 2003; Nethengwe, 2007]. Consequently, vulnerability studies cannot be complete without reference to the capacity of the population to absorb, respond and recover from the impact of such events. This therefore implies a flood event within the same area might go unperceived by some households or may be catastrophic for others due to differences in absorption capacity or level of human development (Figure 1).
Figure 1: Comparison of flood impacts (death toll) and human development [Adapted from Peduzzi et al., 2005]
19 From the above, flood vulnerability could be seen as not just an issue of mere proximity to flood zones but a product of the flood as a physical, political and socio-economic phenomenon. Consequently, the strategy of removing or relocating affected persons or activities in a floodplain does not address effectively flood vulnerability but deals only with the risk component of vulnerability.
With permanent exposure to floods, vulnerability to loss will continue to increase, even as our ability to forecast events and warn areas at risk increases. What this suggests is that it is absolutely imperative to direct efforts toward defining vulnerability and understanding the social, political, economic and perceptual factors that are at work. Vulnerability is increasing because of increases in population and we also know that this varies from place to place, due to the above factors [Gruntfest & Handmer, 2001]. Further, different segments of society are not equally vulnerable: sometimes resulting from factors under their control, sometimes from factors beyond their control; sometimes in a predictable manner, sometimes in a manner that is not so predictable [Pelling, 1999; Wisner et al., 2004; Zahran et al., 2008].
Physical science and technological advances are critical, but experience has shown that a similar effort that focuses on understanding social systems is equally necessary. Studies have indicated that socially vulnerable populations suffer greater property loss in disaster events thereby prompting researchers to theorise that minority citizens are affected unevenly by disasters because they are more likely to reside in older, poorer, high-density, segregated and disaster-prone areas [Blaikie et al., 1994; Gruntfest & Handmer, 2001; Todini, 1999; Zahran et al., 2008].
In order to reverse this trend of increasing flood vulnerability, an understanding of how settlements grow and what will be the impact of autonomous growth on their susceptibility to floods [Zevenbergen et al., 2008] is required. Although comprehensive and systematic research is still lacking, a number of studies substantiate the general assumption that urbanisation is largely an uncontrolled process. Based on estimates of the United Nations, only 5% of new development ongoing in the world’s expanding cities is planned [Gentleman, 2007]. The situation in Diepsloot is an important one given that these autonomous structures would be more vulnerable to floods with massive losses worth protecting. This was not the idea at conception by the government but was hijacked by low
20 and zero income people in search for job opportunities in the neighbouring high-income areas.
Adaptation of these settlement structures which fall within the 1:50-year and 1:100-year floodlines would be economically important through property and life saves within the Diepsloot township. In 2007, the Regional Spatial Development Framework reported of an estimated 60 000 people living in about 17 000 informal structures within the Diepsloot township [DPUM, 2007]. Adaptation would therefore be a proactive flood management method salvaging the issue of damage and land for relocation as well as aid to victims which never completely repays the losses.
The development concept of ‘sustainability’ involves mitigation and adaptation measures being brought together simultaneously and more strategically in the overall framework [Hunt, 2002]. This more holistic approach has the merit of ensuring that economic activities are directed so as to complement the specific technical and organizational measures needed for natural-disaster reduction, as well as for mitigation of, and adaptation for climate change which will reduce the impacts on humankind [Jonkman &Vrijling, 2008; Saavedra & Budd, 2009].
2.6.2 Mapping flood vulnerability
Maps are a good representation to identify the danger or hazardous sites according to the area of influence of the event. They have been in used for centuries to support not just disaster managers but also land managers and planners, and which has been facilitated over recent years by the use of GIS and Remote Sensing [Mishra, 2002]. In recent times, the availability of powerful computers, digitised maps and development of GIS have transformed the design, quality and utility of maps. GIS can help in organising, analysing, displaying and verifying enormous data that help decision-making. Mapping has become an integral part of modern decision support systems through which disaster management is being rooted. This is to enable sound decisions as precision to affected environments are known. This will therefore facilitate better policy analysis, preparedness and quicker response that can help save life and property.
The role of mapping for disaster management can be analysed with reference to the following phases: (i) Hazard assessment and vulnerability analysis; (ii) mitigation and preparedness; (iii) pre-disaster phase; (iv) response; (v) loss and damage assessment; and
21 (vi) rehabilitation and reconstruction [Nethengwe, 2007; Maantay & Maroko, 2009]. Vulnerable areas in the context of various types of disasters with floods inclusive need to be identified and mapped with a view to planning of prevention, mitigation and emergency response measures. Maps will show areas having different degrees of vulnerability and those prone to multiple disasters that will help the disaster managers prioritise the response mechanism [Mishra, 2002]. In the case of Mozambique, flood disaster management has been greatly enhanced through remote sensing satellite mapping (Steinbruch et al., 2002). Through this mapping, not just were at-risk or affected areas identified but also the installation of emergency shelters was made possible in close proximity to affected population (Gall, 2004).
Mapping of flood vulnerability Diepsloot township will aid town planners in the City of Johannesburg to understand its populace at risk and complimenting this with coping strategies develop adaptation measures within planning. It is clear then that such maps are both important and useful for guiding development away from floodplains and for numerous other flood management applications. However, it is also apparent that the uncertainties associated with recording and modelling flood events are practically significant, even for relatively simple inundation estimates and inherent to the hazard mapping process [Mishra, 2002; Viljoen & Booysen, 2006; Hankin et al., 2008; Myeong & Hong 2009].
It is only after areas of flood vulnerability are mapped out that various causes can be examined since areas respond to hazards differently. Given that a major component of urbanisation and contributor to flood occurrence is the increase in impervious surfaces [Zahran et al., 2008] and as these increase, there is a corresponding decrease in infiltration and a rise in surface run-off. The areas that are most vulnerable to damage by flooding are urban landscapes which according to van der Sande et al. [2003:218] “…are composed of varied materials (concrete, asphalt, metal, plastic, glass, shingles, water, grass, shrubs, trees and soil) arranged by humans in complex ways for the construction of houses, transportation systems, utilities, commercial buildings, gardens, parks, playgrounds and other recreational landscape.” The damage of these floods would vary within a formal and informal residential area (Figure 2) since the flow is hardly intercepted by recreational surfaces like gardens and parks. This increases the volume of flood waters and consequently its damage on their dense layout of dwelling units.
22 Figure 2: Impact of urbanisation on runoff quantities [Adapted from Viljoen & Booysen, 2006]
2.7. Methodological approaches in flood disaster risk reduction in South Africa
Disaster risk is largely an outcome of unsustainable developmental practices or exacerbated by urban development. We need to understand the processes that shape urbanisation and how they create or increase risk to hazards. Consider the city as an evolving biological system where there is no simple-one-way line of causality in the production of human or environmental conditions and so risk in the city is an outcome of many feedback loops and thresholds competing ideas, mechanisms and forms [Pelling, 2003]. Hence urban disasters are viewed as a result of inefficient urban management, inadequate planning, poorly regulated population density, inappropriate construction practices, ecological imbalance and infrastructure dependency [Pelling, 2003; Lewis & Mioch, 2005]. Good governance is a necessity in reducing urban vulnerability especially among the urban poor communities.
It is as a result of this vast background that various risk reduction measures have taken different methodological approaches in order to tackle the problem. Disaster risk reduction measures in South Africa focus on structural measures and non-structural measures are more orientated towards early warning systems that often do not assist the at-risk communities as warnings fail to reach them on time. So in order to achieve a balanced flood risk management strategy, both an assessment of the flood hazard and vulnerability conditions of an at-risk population is essential. A number of studies on flood disaster
23 management which have been undertaken in South Africa would be reviewed for methodological approaches applied.
Myburgh in 1991 used integrated hazards framework to explore the physical, behavioural and social aspects of flood and drought hazard in order to gain a more comprehensive understanding of the complex interrelationships at play in defining the hazardousness of the arid and semi-arid regions of the previously called Cape Province of South Africa. She adopted a human ecology approach through which a range of human adjustments and adaptations to the hazard were identified. Miller in 1997 adopted the technical-fix approach to develop a structural flood risk reduction strategy relying on the construction of physical structures to avoid flooding of the flood plains from rivers and storm water systems. Non-structural measures identified included proper development planning awareness or preparedness and social protection that gained increasing importance as time went on.
Mgquba [2002] investigated the physical and human dimensions of flood risk in Alexandra. The studies applied the Participatory Action Research (PAR) model [Blaike et al., 1994] to unpack the root causes, dynamic pressures and unsafe conditions of severe flooding of the Jukskei River in the township that increased vulnerability and associated risk of the urban poor living in the floodplain. It adopted a political ecology approach to flood risk because of the PAR model.
Pyle [2006] on his part looked at vulnerability analysis as being dependent heavily on census data at municipal scale. Through adopting a human ecology approach he ground- truthed the census data with field research which was qualitatively done through household interviews. This constrained the study’s explanation of the root causes of vulnerability. Through this temporal, spatial and impact characteristics of severe convective storm hazard, associated risk could be investigated. He then used this conceptual framework to emphasise the combined role played by hazard and vulnerability conditions in defining risk.
Durham [2007] adopted a disaster reduction framework to assess the effectiveness of existing flood risk reduction efforts along the Bath River in Western Cape. He conducted a risk assessment that considered physical hazard, the human, financial, technical or institutional capacity to manage the flood risk along the respective river. He used a
24 participatory approach of interview, focus groups and consultations with the community and key stakeholders. This public participation input was limited to the hazard analysis and damages.
Van Bladeren et al. [2007] criticised the use of deterministic flood hydrology looking at run-off and rainfall input since they have the same probability of exceedance. This method could only be applied to sites with no flow data for a range of storm durations, changing catchments conditions and provide an indication of the expected hydrograph shape for a storm event. They used an integrated systematic historic and palaeo-flood data to provide estimates of the flood peaks and their associated probabilities for all the regions of South Africa.
Reviewing the three perspectives about flood hazards, Nethengwe [2007] deduces a shortcoming to these conventional explanations as masking socio-economic and political dynamics as well as power relationships that enhance flood vulnerability. Some conventional methods used to combat floods have also been developed upon these perspectives. These have only succeeded partially as some techniques end up increasing flood vulnerability of the local populace. He then brought in the historical perspective into flood mitigation by using Participatory Geographic Information Systems (PGIS) to map vulnerabilities in the Limpopo province with two case studies.
This study shall then complement the storm management study commenced in 2009 for the City of Johannesburg, through which it was recommended that specific studies like this be done for effective management [Van Huyssteen et al., 2009]. The spatial dimension would be combined with a social survey to further identify areas vulnerable to flooding which would illustrate to what extent the people are at risk and eventually decision/policy makers within the City of Johannesburg to understand the flood vulnerability situation in Diepsloot township.
The perceptions of the people shall also be considered in policy developments since the survey shall find out what coping measures are in place for the community to adapt with floods. This study makes use of the floodline research done by SRK in Diepsloot to create a vulnerability map that can be used to assess households exposed to different flood events. The floodlines were calculated based on the physical hazard whereas the local knowledge shall be included to ascertain if other vulnerable areas do exist beyond these limits.
25 A major barrier that must be overcome if flood disaster management is to become more socially inclusive, concerns technological expectations the public have of the role and capacity of management institutions to deal with hazards like flooding [Wisner et al., 2004]. Expectations that floods can be eradicated completely, or that defences should be erected on all floodplains, regardless of the costs and benefits, are widely held among members of the public. In Diepsloot township in particular the populace feels the municipality and local councillors are to be blamed for every flood event that devastates their households. They fail to see their own contributions in the devastating nature of the floods. These unrealistic expectations generate disappointment when floods continue to occur (often aggravated by media coverage of the nature of events and who is to blame for them).
A successful management programme for disasters such as floods must therefore be integrative, with roles defined for every stakeholder. Since comprehensive hazard maps have the potential to define areas that are exposed to flooding (that are not revealed by floodline assessments) and might, therefore, benefit from attempts to reduce vulnerability [Brown & Damery, 2002; Maantay & Ziegler, 2006]. These maps provided the opportunity to change the way in which flood vulnerability information for this area is communicated to the public, as they delimit the geographical extent of flood inundation for events of a specified magnitude (1:50-year and 1:100-year).
26 3. METHODOLOGY
This chapter presents the methodological approaches used in this study. It starts with the overall study design, proceeds with a description of the study area (geophysical characteristics and demographics) before giving a detailed explanation of the methods used in acquiring and analysing data. This is treated through the various objectives of this study. The data acquisition techniques and analysis to attain each objective are examined in turn.
3.1. Overall study design
This study employs a case study to develop and test a modified methodology for assessing flood vulnerability and adaptation strategy in Gauteng through a comprehensive identification of at-risk areas. The case study area selected was a township already known to be vulnerable to flooding, Diepsloot, comprising both formal and informal sectors. The baseline methodology is a conventional flood vulnerability assessment using GIS to determine floodlines and hence map vulnerable areas. The modified method uses a social survey from which further at-risk areas may be identified, and mapping these additional areas using slope estimate tools in GIS. The overall study concept to reach the combined flood vulnerability assessment is represented diagrammatically in (Figure 3). This approach used the information from the social survey and GIS as a tool to do slope evaluations which generated a comprehensive flood vulnerability map for Diepsloot township.
Flood vulnerability assessment
GIS Flood Social survey vulnerability Case Study - (vulnerability and mapping using Diepsloot adaptation measures) floodlines using questionnaires
Combined approach for vulnerability mapping
GIS Slope calculation and mapping
Figure 3: Study design for this research
27 3.2. Study area
Diepsloot township derived its name from a river with this same name, running in the northern part of Johannesburg. Diepsloot is an Afrikaans word, meaning “deep trench”, which simply signifies the landscape of the river. The settlement is located at the far north- eastern edge of the City of Johannesburg bordering the City of Tshwane (Figure 4) and about 30 km² from the Johannesburg CBD. It is situated on latitude S 25° 56' 04.69" and longitude E 28° 00' 44.43". It is a predominantly African township, the creation of which was initiated (1992) during the apartheid era (pre-1994), although extensive further growth occurred during the post-apartheid era (1995). It has been described as a place for “…cast- offs or refugees of other areas” [Harber, 2011:9]. It is a dense, unplanned and impoverished settlement located on typically marginalised area, being slopes which culminate into a wetland and a tributary of the Jukskei River (Figure 4). Acute poverty, which can be related to day-to-day survival, takes much higher priority than care for the environment in such areas, as is the case with Diepsloot township.
Figure 4: Map and geographical location of Diepsloot township [Adapted from Google Earth, 2010; CoJ, 2009; AGIS, 2001]
The creation of Diepsloot township was as a result of two major relocations of people from other parts of the city, the first being from Zevenfontein, where private land had been
28 invaded to create an informal settlement. The people from this relocation were allocated stands in Diepsloot West. The second relocation was from Alexandra into Diepsloot Reception Area and Extension 1, as part of a de-densification programme in Alexandra to reduce human exposure to hazards like floods, particularly from dwellings (shacks) that had been constructed within the annual floodlines along the banks of the Jukskei River. The housing conditions in Reception Area (Diepsloot) were not necessarily an improvement, leaving some residents in similar or worse situations. This has caused a number of violent community protests for better living conditions [Harber, 2011].
The new Government housing programme under the Reconstruction and Development (RDP) policy was adopted in 1994 [ANC, 1994], and implementation around the country commenced in 1997. Under this programme, improved social services and settlement structures, such as drainage systems, were delivered to parts of the populace of Diepsloot township as from 2001 [Harber, 2011:46]. Some residents were allocated and moved into formal RDP (~40 m2) brick houses. This formalisation of Diepsloot township is a long term transformation process. Due to the demographic dynamics, new informal settlements have been established around the core of this township, faster than the Government has been able to provide formal housing to the historical backlog of demand. In 2007, the designated 5.2 km² land area of Diepsloot township comprised 24% formal and 76% informal housing [CoJ, 2007].
The history of sporadic relocations into this township and the rapid unplanned expansion of the township have created marked inequality in accessing services and community facilities [Bénit, 2002]. During field visits, it was observed that Diepsloot West has access to water, electricity, waste removal services, sewage and road infrastructure, while Extension 1, Reception Area and others had limited access to basic services, wide spread poverty, unemployment etc. These latter areas were situated on floodplains with poor building materials, overcrowded living conditions, and exposed to a number of environmental hazards.
3.2.1 Climate and Rainfall
This area receives most of its rainfall in summer, which amounts between 650 to 750 mm per year. Temperatures vary between 7ºC and 35ºC for the summer and -5ºC to 24ºC for the winter months. Daily rainfall data from SAWS was obtained for this study in order to trace rainfall patterns and possibly a flood history could be established. Rainfall over the
29 area was quantitatively determined from Irene, the closest SAWS weather station to Diepsloot. The annual summer rainfall (summed from October to March of the following year) is graphically represented to show long term trends over a 51 year period (1960- 2010) (Figure 5). The results indicate 1997 as the wettest year within the period. The trend line indicated there has been a mean increase of ~12% in summer rainfall over the 50-year period years (Figure 5).
Figure 5: Annual summer rainfall (summed from October through March) for Diepsloot [Data from SAWS: 1960-2010]
Inspection of the daily rainfall values over the past fifty years showed years with peak daily rainfall being summer seasons 1969/70 (18 October, 1969) and 1996/1997 (4 March, 1997). The monthly mean rainfall peaks in January and December - this confirms the normal trend of summer rainfall over the Highveld with high monthly averages recorded from December to February. However, the peak monthly rainfall (370 mm) occurred in the month of February (Figure 6). Residents showed knowledge of this while noting February as their flooding season over the past years, but the 2010/2011 summer season experienced a change with flooding from December.
30 400 350 300 250 200 150 100
Monthly rainfall (mm) rainfall Monthly 50 0 1 2 3 4 5 6 7 8 9 10 11 12 Time (months of the year)
Figure 6: Monthly rainfall over Diepsloot [Data from SAWS: 1960-2010]
In order to establish a recurrence period of rainfall intensity, frequency of exceeding defined threshold values were calculated on an Excel spreadsheet for monthly rainfall in Diepsloot. From the threshold values, the probability of recurrence for these values was established (Figure 7). This probability then enabled the calculation of recurrence time for each threshold value. The recurrence time ranged from 4 days (return frequency of any rainfall day with precipitation exceeding 0.1 mm) to 51 years (for the highest recorded rainfall event, above 120 mm per month) (Table 1). .
Figure 7: Probability of rainfall above monthly thresholds for Diepsloot
31 Table 1: Monthly rainfall threshold return frequency for Diepsloot (Data from SAWS)
Monthly Rainfall Threshold (mm) Return frequency
0.1 4 days 10 15 days
20 40 days 30 87 days 40 194 days 50 1.2 years 60 2.1 years 70 3.9 years 80 5.7 years 90 17.0 years 100 25.5 years 120 51.0 years
3.2.2 Hydrology
Diepsloot has a seasonal drainage line with a highly disturbed watercourse that cuts through the settlement. It has a trellised drainage pattern whereby numerous seasonal streams feed into the main watercourse (Figure 8). This watercourse is a tributary of the Jukskei River. The watercourse with its surrounding wetland forms the open space area running through the township. The water channels are highly disturbed concreted roads cutting across the wetland that cause damming back into the wetlands, further intrusions with earth to create footpaths from one suburb to the other, and by illegal waste dumping by residents (Figure 9); the consequence of which has been blockage of these channels. Opposite the formal housing on the west bank, protected by a dammed bank, is the undammed bank of the informal housing, which becomes prone to flooding by inundation during heavy rains.
For the seasonal streams, the channels become dry ground during winters and shacks are raised along this area. In summer these channels become streams once more and these newly built households become vulnerable to flooding. They also suffer from waste being washed into their adjacent dwelling units from illegal dumping in the channels.
32 1000 m
Figure 8: Diepsloot river catchment (Ngie, 2011) (Enlargement of squared site in Figure 9)
Formal housing with Seasonal streams damming along the water way
Road construction and intrusions for footpaths across the wetland
Artificial dams
Informal housing without protection and exposed to flooding. Wetland
Figure 9: Google earth image illustrating human disturbances along the Diepsloot floodplain [Credit: Google Earth 2010 Image]
33 3.2.3 Geology and soils
Diepsloot is underlined by the Halfway House Granite Dome with typical gravely soils. These soils are intensively weathered with deep drainage line intersections and a gently rolling topography, with shallow, coarse, nutrient-poor, well-drained soils [Bredenkamp et al., 2006]. These soils are characterized by open structures and, coupled with the relatively flat terrain (Figure 10), are easily saturated when it rains, producing high volumes of runoff.
Figure 10: Relatively flat terrain within the floodplain in Diepsloot (Photo credit: Ngie, 2011)
3.3. Demographics
Diepsloot township was established in 1995, to house informal residents evicted from Zevenfontein, with further relocations in 1996 from overcrowded and flood prone areas) of Alexandra. The township witnessed a population boom from approximately 3 273 households in 1996 to approximately 23 000 households in 2007 [CoJ, 2007]. Its proximity to higher income city and residential hubs like Sandton, Randburg, Midrand and Fourways has continually attracted the new migrants for associated perceived economic opportunities. This growth has occurred with very little associated infrastructure
34 development (roads, sewerage) or service delivery (waste removal), since the relocation of people to Diepsloot was intended to be temporary measure.
In all, in 2010 Diepsloot township has a population of approximately 200 000 inhabitants living within an estimated 23 000 Households [Harber, 2011]. The population is reported to be at 1 076 people per square kilometre and a household size average of 3.4 persons per household [DPUM, 2007], which was also confirmed by this study. In addition to housing, the major problems confronting the population include poverty, unemployment, lack of social and economic opportunities, and limited public transport. Unemployment levels are reported to be at about 54% (among the potential labour force), with 73% living below the poverty line (less than one United State dollar per day) [DPUM, 2007; Harber, 2011]. The population boom has caused indiscriminate settlement in risk-prone areas, such as flood plains.
3.4. Research methodology
This research employed both qualitative and quantitative methods to gather and analyse primary data. It started with a consultation of secondary data through desktop studies where a theoretical framework was developed on what is required for vulnerability mapping. A case study methodology was selected, since it has to deal with specific questions of what, where and how. This method of conducting research has been identified as advantageous over general enquiries since it has “…the ability to contend with a variety of evidences such as documentation and interviews while retaining the holistic and meaningful characteristics of real life events” [Retief, 2007:87].
According to Jick [1979] the mix of two research techniques to examine a problem within the same study is known as the triangulation approach or Convergent method. Most often it is the use of qualitative and quantitative techniques to generate data for a study of the same phenomenon. One advantage of this triangulation approach is that it enhances confidence in findings since the two methods interact to complement one another and not just cut across the qualitative-quantitative divide [Hoque, 2006]. Another advantage has been the deepening and widening of a researcher’s understanding. As a research method it has played a useful role in the socially situated process of empirical data collection [Olsen, 2004]. This approach was employed for this study to develop quantifiable schemes for coding complex data sets from the survey and to avoid guesses in an effort to reduce bias.
35 One of its challenges is being able to tell whether or not results have converged since the qualitative method is more subjective than the quantitative.
The data collection techniques will be discussed according to the various methods used and for which objectives they were intended to address, dwelling on the collection of both primary and secondary data. The primary data shall mainly be sourced through field visits (structured and unstructured interviews, observations, including taking photographs) to establish local knowledge about flood vulnerability in Diepsloot. The secondary data were to be from various stakeholders and sourced according to their disclosure agreements. The stakeholders included the university library, SRK Ltd (an engineering consulting company), Southern Mapping Company (Pty) Ltd and City of Johannesburg.
3.5. GIS conventional floodline mapping
3.5.1 Acquisition of base maps
Aerial photograph tiles and contours covering the study area were obtained from Southern Mapping Company, with authorization from the City of Johannesburg. This was to enable a detailed view of this area, on which land use features, like residential and roads which are required for household vulnerability to floods, were distinguishable. Other GIS layers, such as rivers, were also included in the package collected from City of Johannesburg.
3.5.2 GIS mapping procedures to generate floodlines
Flood hazard assessment for Diepsloot, and floodlines of 1:50- and 1:100-year recurrence were carried out by SRK [2010], through the use of terrestrial survey data merged with a 1 m contour survey, entered into the HEC-RAS model (Hydrologic Engineering Centres River Analysis System)3. This model is used for the hydraulics of water flow through natural rivers and channels. Control structures which included boundary conditions and flow regime were entered into the model manually. The peak flow rates were calculated using the Soil Conservation Service (SCS) model which simulates soil classification, land use and conventional data of hydrology and meteorology to estimate run-off from a small watershed, of which Diepsloot is an example [Mahlangu & Braune, 2010]. An average of the peak flow rates was then recorded. With the results from the HEC-RAS model and peak flow rates, the floodlines for Diepsloot were determined for 1:50- and 1:100-year (Appendix B) and provided in digital format.
3 [http://www.hec.usace.army.mil/software/hec-ras/ Accessed on 17 January 2012]
36 3.5.3 Mapping flood vulnerability
The question this analysis seeks to answer is: What is the geographical extent of Diepsloot households vulnerable to floods of risk either 1:50-year or 1:100-year? It is worth noting that one of the key benefits of a GIS is that data collected from different sources can be related to generate new, previously unknown information in a spatial context. This can be achieved through overlay techniques with location information or through combining attribute information using statistical or modelling techniques [Sanyal & Lu, 2005].
The ArcGIS™ system is an integrated GIS, which provides a framework for implementing GIS for users. ArcGIS version 10-Student License was used to build a geo-database and carry out spatial analysis, including buffer analysis and union analysis. This study applied straightforward standard GIS techniques within ESRI’s ArcGIS package [ESRI, 2010]. These geo-processing techniques include a number of operations, generally falling in the category of overlay functions (e.g. intersect) which allow the creation of new information which does not exist in any of the input data sets [Maantay & Maroko, 2009; Li et al., 2010].
In this case, overlaying the various calculated floodlines onto an aerial photograph of Diepsloot will demarcate the human settlement structures or infrastructure at risk. With the recommended buffering of 32 m placed beyond the 1:50-year floodline [CSIR, 2005], an extension is expected from the floodline to where settlement structures can be laid. This is however, has not been the case within this settlement, thereby increasing vulnerability to flooding at various depths.
3.6. Survey of local knowledge on flooding in Diepsloot township
3.6.1 Structured household interviews using questionnaires
The qualitative methods used here involved one-on-one interviews conducted among a randomly selected sample of Diepsloot township residents. The one-on-one interview technique is advantageous over the dispatch of questionnaires as it creates an interaction between interviewer and interviewee. It also creates an opportunity whereby unclear questions can be explained and the respondent can raise important issues previously overlooked by the researcher.
37 The interviews were based on a structured questionnaire format (Appendix A). The interviews were structured so as to generate quantitative data for comparative purposes in determining people’s perceptions on the vulnerability of their community to floods and what coping mechanisms they employ. This was done through closed-ended and open- ended questions. The open-ended questions accommodated discussion as it allowed for explanatory notes on the rationale of every experience or situation so encountered.
According to Tapela et al. [2009:10] community engagement is to be governed by “the principles of core values of respect, reciprocity, equality and mutual respect”. The survey did comply with the above principles, though there were situations of irregularities4 and the team would respond by leaving such vicinities. However, the field team was accompanied by someone the community could easily recognise within the team. The community members were comfortable with this gesture. This was a boost to our identification within the community, since we had no uniforms (e.g. university branded clothing), as had been suggested by some of the community partners. The field team was made up of the community members sourced through a voluntary sensitization group and a colleague to the researcher. The researcher therefore had five other persons to assist in the field survey.
After a household was spotted randomly for interview, the prospective respondent, who could either be the household head or a representative, was introduced to the research idea and team. They were then assured of the protection of their identity and that all answers were to be considered only for the study, since it was based on personal experiences and perceptions. However, they were also assured of not being under any obligation to be interviewed or to complete the questionnaire, and so could quit at any stage. In this light, contact details of the research supervisor were given to them in a letter that briefed them on the research for any queries or feedback.
The questionnaire (Appendix A) was drafted to incorporate four different sections that included: Section A: The socio-demographic section, which included specific household characteristics like gender, age, education and number of people within the household.
4 These were situations of hostility and violence from respondents misjudging interviewers to be working for the government.
38 Section B: Housing quality index, this was meant to evaluate prominent construction materials for the dwelling units in Diepsloot township. Section C: Perceptions and experiences for flood causes, impacts and coping strategies in Diepsloot township, since they first moved into the township. Section D: Location factors and other perceptions that were meant to probe why they were settled there and, if it was considered unsafe for human habitation, would they be willing to move.
3.6.2 Pilot study
A pilot study was conducted with eight households, which enabled the researcher to understand timing, language and other behaviours of respondents within this area. From this, the field assistants were trained in administering not just the questionnaires but to understand certain community behaviours and how to overcome them. The field assistants were trained by the researcher for one day on how to carry out the survey, after which each person was given a copy of the questionnaire so that they could read and understand the questions before approaching interviewees, especially for purposes of translation. The training focussed on how to: approach the respondents; frame the question (especially for translation purposes); clarify the proposed answers (if necessary); record responses; and how to conclude the interview.
3.6.3 Administration of questionnaires through households
A sample size of at least 100 households was targeted and after eight days with the field teams, a total of 118 households were interviewed. Out of this number, two were incomplete as the respondents quit the interview, and one was not considered randomly sampled, as proven by the Global Positioning System (GPS) coordinates (two separate interviews of the male and female occupants of the same household had inadvertently been conducted by different team members).
The randomised sampling of respondent households was generated through a systematic sampling technique using a shape file with streets overlaid on a Google Earth map of the area. Through this method, the numbers of streets were identified along which a random interview could be conducted. Numbers could not be randomly placed on households since congestion made it impossible to differentiate between individual houses on the satellite image. This is as a result of lack of pre-planning in construction of the houses and most
39 stand boundaries are merged without one being able to differentiate between households physically, unless informed by the occupants.
Randomness was ensured by the researcher placing interviewers on streets as directed by the map. If a team was placed at the beginning of the street, the subsequent team was placed at the opposite end of the subsequent street. The team was required to enquire with respondents who were willing and available for the interview, during which a negative response simply meant the interviewer should proceed to next household until a positive response was obtained. In the case where respondents within the household could not represent the household heads, e.g. if the head was away at work, an appointment was made for such interviews to be held over the subsequent weekend.
3.6.4 Data analysis from questionnaires
Data from the questionnaires was coded into cases (interview numbers/respondents) and variables (questions/responses) and captured quantitatively in a Microsoft Excel™ spreadsheet. Frequency tables and cross-tabulations for comparisons between scenarios were prepared where necessary (carried out by Statkon-UJ). The P-Chi square test was used to evaluate significant relationships in cross-tabulations. Meanwhile the open-ended questions were analysed qualitatively as response were used to build arguments on various subjects and field pictures used to complement them.
3.6.5 Field observations and limitations
During the fieldwork survey, many informants shared emotional and personal experiences. In the interest of confidentiality, no names of informants appear in the research. There is also sensitivity with regards to photographs representing affected informants’ dwellings both from the interior and exterior. However, informants’ consent was sought prior to capturing photographs. Where they rejected the idea, such photographs were not taken.
A major problem encountered was that of using the handheld GPS to identify the location of the household, as several interviewees and residents agitated on remaining anonymous and that their dwellings should not be revisited. Some threatened to ‘grab and run’ with it
40 from the interviewees. There was great fear5 walking around the township with the GPS instrument, just like mobile phones. It became a drawback for onward mapping.
The greatest difficulty during fieldwork was the language barrier, which often limited the depth and at times the accuracy of some interviews6. It is worth noting with caution that as an outsider one will never experience the true reality of the hardships experienced by a vulnerable population, since the outsider will always return to a place of comfort outside that environment, whereas the local residents, whose conditions the outsider tries to document or study, have no such alternative.
The fieldwork also posed the challenge of respondent fatigue because of the length of the interviews as well as the interviewer’s fatigue. Where language was not a challenge the interviews lasted between 30 to 45 minutes. This time was exceeded by about 15 to 30 minutes if language was a barrier as both questions and responses had to be translated. However, in situations where respondents showed willingness to speak, the researcher built on this opportunity to allow the interviews to turn into open discussions with shows around units which lasted from 1 to 1½ hours.
3.7. Classification of housing structures in Diepsloot township
The development of Diepsloot township reflects the local housing crisis within the City of Johannesburg rather than rural-urban migration as is the case with other townships. This has been proven by a social survey conducted in 1999 by Setplan7 Ltd that indicated that most inhabitants originate from surrounding areas (42% from Alexandra) [DPUM, 2007]. The local authority, via its Department of Development Planning and Facilitation, provided statistics to Setplan, which revealed an acute housing shortage of approximately 17 000 units (by mid-2006) in the Diepsloot region. The housing shortage situation is a serious problem and requires immediate attention. It is estimated that 60 000 people reside within the 17 480 informal structures [Harber, 2011], many of them in 3 m × 2 m shacks assembled from scrap metal, wood, plastic and cardboard (Figure 11). These shacks are constructed with these materials since these materials are acquired free as scrap or at low cost, and can be assembled within simple hand tools.
5 Harber (2011:3-6) describes the high crime wave in Diepsloot with robberies and violent protests during which residents fight against themselves (different suburbs and sectors such as taxi drivers). They are also notorious in attacks against passersby and strangers to their community. He quoted some newspaper description as a place of violence. 6 The researcher is a national of Cameroon, and is not fluent in South African vernacular languages. 7 Town and regional planning consulting company in Johannesburg
41 Figure 11: Informal housing structures in Diepsloot township (Photo credit: Ngie, 2011)
3.7.1 Data generation for housing structure
This was done through the questionnaires where residents were asked to describe their housing structure by construction materials. The questions were sub-divided to probe the predominant materials used for roof, walls and floor. The researcher also instructed the respondents were too timid to reveal some of this information. In some cases, carpets were placed on bare earth or dirt, or over a plastic sheet.
3.7.2 Analysis of data on housing structure
Data on housing structure were coded, since they were closed-ended questions, and frequency tables generated. These tables were further used to perform cross-tabulations with various scenarios. The cross-tabulations were to probe the relationship between housing structure and flood vulnerability. Flood impacts were used to compare against
42 housing structure. This was to enable the researcher investigate the level of devastation on dwelling units in relation to their predominant construction materials.
3.8. Combined local knowledge and physical mapping approach
Local knowledge which was probed through the community survey identified further areas outside of the floodplains8 in Diepsloot township being exposed to flooding. Residents reported the experience of their dwelling units usually damaged by flooding during heavy rainfall events. These areas could have been identified with GPS coordinates but the appliance could not be used effectively as reported above in field limitations. So these areas were identified through their extension or unit names mainly by numbering (e.g. Extension 1, 2, and so on). Through the community survey, reasons for this flooding experience were identified to be either man-made, such as dwelling unit structures and drainage systems, or natural, such as landscape and rainfall.
With this knowledge, 1m contours for the area (sourced from the City of Johannesburg) were used in ArcGIS to measure the slope angles, which would aid in corroborating those further areas outside floodplains identified by residents. The slope measurements were overlaid onto the aerial photograph and flood vulnerable areas both along the watercourse margins and beyond were clearly identified. These areas were distinguished according to various slope measurements with different colours into classes. These classes were determined by dividing the range of slopes into eight linear equidistant intervals.
8 Floodplains used in the sense of areas adjacent to perennial or seasonal watercourses, subject to intermittent inundation following heavy rainfall.
43 4. RESULTS This chapter presents the results from the social survey and GIS analysis. It presents results according to the objectives of the study, starting with the socio- demographic characteristics of the sampling population. It then proceeds with results on mapping using floodlines, local knowledge about flood vulnerability, housing structure in Diepsloot township and finally the combined approach through slope measurements. This is the evidence needed to draw conclusions that the objectives were attained.
4.1. Socio-demographic characteristics of respondents in Diepsloot township The sample of 118 respondents had one disqualified leaving a sample size of 117 for this study. The socio-demographic data revealed that more males were sampled than females of an average age of 25-40 years (Table 2). The gender difference is however, insignificant given the percentages of 56.4% and 43.6% for males and females respectively. More informal households (61%) were sampled at the end of the research. Most of the dwelling units (79%) were owned by the respondents, who had lived in Diepsloot township on an average 7.4 years. The average household size was 3.4 persons that could be considered as being at flood risk if that household is vulnerable.
Table 2: Socio-demographic characteristics of respondents
Characteristics Categories No. of respondents % of respondents
Gender Male 66 56.4 Female 51 43.6 Age 16-24 14 11.9 25-44 82 69.5 45-59 18 15.3 60+ 4 3.4 Education Degree, diploma or certificate 8 7.2 Matriculate 25 22.3 Grade 10 or 11 40 35.7 Grade 8 or below 36 32.1 None of the above 3 2.7
Dwelling type House 9 7.6 RDP 37 31.4 Informal 71 60.7 Ownership Owned 93 78.6 Rented 25 21.4
44 4.2. Mapping flood vulnerability using the floodlines
An aerial image was used as the base map onto which overlays of the floodlines for various depths (1:50-year and 1:100-year) were made. This indicated the dwelling units or households below it. The vulnerability could not be characterised as high, medium or low, since topographic data were missing. The study therefore, just mapped to what extent households in Diepsloot township would be exposed to a 1:50-year or 1:100-year floodlines (Figure 12 & Figure 13). The dense nature of the dwelling units also made it impossible for the researcher to calculate the number of households/people at risk to flooding.
The results of the conventional mapping which were based only along the floodplains (adjacent to the watercourses) indicated many dwelling units were constructed below the floodlines. The extent of the settlement structures below both the 1:50-year and 1:100-year floodline was glaring (Figure 12 & Figure 13). These structures were mainly informal. The floodlines are indicators to enable safe layout of houses but are not fixed limits for flood waters. This meant that even dwelling units found beyond the floodlines could still be vulnerable to flooding. Through local knowledge, these sections (beyond the floodlines) were reported and are mapped with the slope measurements as discussed later.
1000 m
Figure 12: Flood vulnerability mapping using 1:50-year floodline (Ngie, 2011)
45 G
G
E E
1000 m
Figure 13: Mapping flood vulnerability in Diepsloot township using a 1:100-year floodline (Ngie, 2011)
4.3. Local knowledge on flood vulnerability The perceptions and experiences of the people were probed from causes, impacts, possible solutions or coping strategies and adaptation measures to living with floods as individual households and as a community. This study also assessed on a general perspective, knowledge about flood vulnerability from the people (Table 3).
Table 3: People's perceptions on flood vulnerability
Strongly Disagre Strongly Characteristics Don’t Agree disagree e know agree
Flooding as major environmental 3 3 0 65 46 problem in Diepsloot % of respondents 2.6 2.6 0 55.6 39.3 Dwelling units expose households to 5 12 17 40 43 floods % of respondents 4.3 10.3 14.5 34.2 36.8 Neighbours would intervene if flooding 5 14 5 76 16 occurred in the community % of respondents 4.3 12.1 4.3 65.5 13.8
46 Some- Characteristics Always Seldom Never Don’t times know
Do other social networks including friends and relatives help during and after 32 40 18 12 13 flooding? % of respondents 27.8 34.8 15.7 10.4 11.3 Do vulnerable households adjust after aid 27 39 22 19 10 or left permanently vulnerable? % of respondents 23.1 33.3 18.8 16.2 8.5
4.3.1 Causes of floods within the Diepsloot township C15. What do you think is the major cause of flooding in your area?9 This question probed the knowledge of the people on what causes floods (Table 4). The researcher assumed there could be more than one cause and required respondents to rank them according to significant contribution to flood disasters. Most respondents identified heavy rains as a major cause (54% of the respondents) of floods in Diepsloot township. This implies they are aware of climate change and its devastating effects as noted by one respondents, “…rains which usually flood our homes come in February but like last year (2010), our homes were flooded by heavy rains in December.”
Table 4: Flood causes in Diepsloot as identified by households
Not Characteristics 1 2 3 4 5 Totals applicable
Construction within wetlands Count 24 19 22 12 4 7 88 or low lying areas % count 27.3 21.6 25.0 13.6 4.5 8.0 100
Waste dumping along water Count 30 1 12 24 13 5 85 ways % count 35.3 1.2 14.1 28.2 15.3 5.9 100 Increased runoff volumes Count 24 17 14 10 15 6 86 from paved areas (surrounding developments) % count 27.9 19.8 16.3 11.6 17.4 7.0 100 Count 32 4 14 12 15 9 86 Blocked drainage systems % count 37.2 4.7 16.3 14.0 17.4 10.5 100 Count 3 48 11 8 11 8 89 Heavy rains % count 3.4 53.9 12.4 9.0 12.4 9.0 100 All the above Count 25 14 0 0 0 0 66 % count 37.9 21.2 0 0 0 0 100 Count 26 1 0 0 0 0 27 None of the above % count 96.3 3.7 0 0 0 0 100
9 Multiple responses required
47 The respondents also identified that construction of dwelling units within the floodplains exposes households to be damaged by flooding. Some argued that their strong dwellings protected them from devastation even within such areas (Figure 14). This is further affirmed by the percentage of respondents who agreed and strongly agreed (34% and 37% that the lack of strength of dwelling units contributes to its vulnerability to flooding) on this characteristic (Table 3). Out of the total sample interviewed, 52% of households reported to have been damaged by floods and 48% not. However, they indicated that not being damaged does not necessarily imply their homes have never been flooded. Some noted that their homes might be safe at times but their surrounding is completely flooded so much so that they cannot leave the house.
Figure 14: Reasons for households not damaged by floods in Diepsloot township
In addition to the causes, one of the interviewee reported the presence of rodents which bore holes through their dwellings (Figure 15). Runoff and storm water is diverted through these holes into their homes. This, according to her explanation, was as a result of floors not cemented or poorly cemented. Therefore, this point is linked to how strong the predominant material of construction was and how efficiently it was done.
48 Figure 15: Rodent holes through which water floods homes (Photo credit: Ngie, 2011)
4.3.2 Coping strategies
The coping strategies were to be assessed from the experiences applied by residents during flooding events. The question limited these strategies to being evacuated10, or relocating11, both of which terminologies were clearly defined to respondents. For the analysis, some comparisons were made to evaluate why households apply these strategies. It was discovered that 72% of respondents who had experienced flooding before, noted relocation as a safer strategy to go by.
Respondents who had moved to Diepsloot township from previously flooded areas like Alexandra also reported relocation as a safe method. A female respondent who had been evacuated from Alexandra explained: “It is impossible to stand on the way of floods and all you need to do is move away.” To test the significance of the relationship a cross tabulation was done for households that had experienced floods in their former area of habitation before moving to Diepsloot township and how they did cope (Figure 16).
10 Being moved out of the area of hazard by authorities 11 Moving out of the area of hazard by victim’s decision
49 25
21 If 'Yes', how did 20 you cope?
Evacuated 15 Relocated
Counts 10 8
5 3 1 0 Yes No Figure 16: Comparing flood experience in former area and coping strategies
Other strategies included making holes on their dwelling units to let flood water out, rushing out for help and staying away from damaged homes. The respondents reported this will depend on the speed of flood water, which is measured by speed being enough to be able to sweep away property and even dwelling units, as high enough to justify moving away, while flood water sweeping away just dirt and lighter objects is considered of low speed and they stay around to protect property. Climbing on higher objects is one of the commonly practiced strategies by the people before rescue teams arrive.
Other methods identified by respondents included using buckets and mops to flush water out of their homes, stay awake when it floods at night, try to block holes through which water gets into their homes, redirect runoff or storm water into other channels away from their homes, or just moving objects within the home to avoid them being destroyed. Some respondents identified staying around their dwellings so as to watch out for any damages and possibly move belongings away. Others reported staying indoors when it rains heavily at nights and early mornings, since streets will be more dangerous crossing to work or for children walking to school.
A comparison was made between educational levels of household heads or representatives, and their coping strategies (Table 5). The educational classes were re-coded to enable the test of a relationship existing between these two characteristics or not. The most applicable coping strategy was climbing on higher objects, despite their educational level. This simply proved that local coping strategies did not require technical or special skills to apply.
50 Table 5: Comparing educational levels and flood coping strategies in Diepsloot township
Question C13.2
Climb on Rushed to Total Relocated higher Others safe areas objects Certificate, Count 1 0 2 3 5 diploma or degree % within rA5 20.0 0 40.0 60.0 Count 2 1 8 3 12 Matriculate Question % within rA5 16.7 8.3 66.7 25.0 rA512 Count 4 1 9 7 17 Grade 10 or 11 % within rA5 23.5 5.9 52.9 41.2
Grade 8 or Count 2 2 10 7 18 lower % within rA5 11.1 11.1 55.6 38.9 Total Count 9 4 29 20 52
The Pearson Chi-square test was applicable for relationship significance in the above situation (Table 5) since it was a 4×4 table. However, the warning after the test stipulated the percentage of expectant values less than 5 being 50% (>20%), hence the p-value could not be used. So, a relationship was established by looking at the values on the table. Another cross tabulation was done between those who have experienced flood devastation in Diepsloot township and if they are willing to move out of the area if considered unsafe as a coping strategy (Table 6). It was clear that a devastating experience of flood is the visa for moving out, as 86% of respondents affirmed this relationship.
Table 6: Flood experience and willingness to move out of Diepsloot township
Question D19
Yes No Total Count 51 8 59 Yes Question % within C13.1 86.4 13.6 100 C13.1 Count 43 11 54 No % within C13.1 79.6 20.4 100 Count 94 19 113 Total % within C13.1 83.2 16.8 100
12 Re-coded the classes for Question A5
51 For a comparison between those households which have experienced devastating floods in former dwelling area and willingness to be evacuated from Diepsloot township, a cross tabulation was conducted (Table 7). A test of significance was applied being the Fisher’s Exact Test13 and it yielded a p-value of 1.000 (>0.05). This means that there is no significant relationship between those households that were damaged by floods and those willing to move if the area was identified as not worthy for human habitation.
Table 7: Comparison of flood experience in former area and willingness to be evacuated from Diepsloot township
Question A4.1
Yes No Total Yes Count 36 60 96 % within D19 37.5 62.5 100 Question D19 No Count 11 8 19 % within D19 57.9 42.1 100 Count 47 68 115 Total % within D19 40.9 59.1 100
Another comparison was then conducted for those who had experienced floods before in their former places of habitation, before being either evacuated or relocated to Diepsloot township, and if they are willing to go through such experience again, if the place was considered unsafe for human settlement. The results indicated most of these people would not want to be evacuated from this area (Table 7) as they reported the problem can be fixed for them to remain there. This calls for the upgrade of townships or informal settlements in-situ rather than moving them from one piece of land to another.
A relationship was to be established between those with past flood experience in former areas as well as in Diepsloot township to whether they are willing to move, if the place was identified as unsafe for habitation (Table 8). For the households without flood devastating experiences, the Fisher’s Exact Test yielded a p-value of 0.046. This means that there is a relationship between households which were not damaged by floods and willingness to move if area identified as unsafe.
Looking at the effect size for the above two relationships, the Phi yielded -0.288. This is a small effect, which means that there is a small difference between the households willing
13 Statistical test used to determine if there are non-random associations between two categorical variables (2x2 tables). [http://www.mathworld.wolfram.com/FishersExactTest.html Accessed on 5 January, 2012].
52 to move and those not willing to move. The negative value indicates the direction of the relationship, which means the households which have not been damaged by floods will rather be moved out of the area if identified unsafe not to go through the painful experiences of other neighbours in this community. The Fisher’s Exact Test was used because it was a 2x2 table to confirm the results obtained.
Table 8: Cross tabulation on past and present flood experiences within Diepsloot township and willingness to be evacuated
Question C13.1 Question A4.1
Yes No Total Count 19 32 51 Yes Question % within D19 37.3 62.7 100 D19 Count 3 5 8 Yes No % within D19 37.5 62.5 100 Count 22 37 59 Total % within D19 37.3 62.7 100 Count 16 27 43 Yes Question % within D19 37.2 62.8 100 D19 Count 8 3 11 No No % within D19 72.7 27.3 100 Count 24 30 54 Total % within D19 44.4 55.6 100
For the success in coping strategies, 68% of households reported their unwillingness to change them in the event of another flood. This was explained by either the successes registered with strategies over the years, or they are less costly and easy to apply or just ignorant of other strategies. The loss of lives during flood events in Diepsloot township was rare as through the survey just five households recorded deaths. Respondents attributed this to the success of their coping strategies. The deaths recoded were children (≤ 18 years) and elderly (≥ 60 years) which would be attributed to their inability to flee from danger.
4.3.3 Flood impacts in Diepsloot township
C13.3 List the articles/assets (from the most valuable 1 to least valuable 6) that were destroyed by the flood. Many households affected by floods record damages on their
53 property ranging from household items being swept away, dwelling unit being completely damaged (Figure 17), and even loss of lives. An overall ranking on items which were most valuable by the total population sampled in Diepsloot township was created. It indicated that beds and bedding were the most valuable items destroyed by floods as 29% of respondents ranked it at first position (Table 9) and the other items arranged in order of priority as judged by the residents.
Figure 17: Flood impacts on furniture and dwelling units in Diepsloot township (Photo credit: Ngie, 2011)
Table 9: Items damaged by floods in Diepsloot township and their value ranked by respondents
Priority Total % of total sample in ranking 1 2 3 4 5 6 count (1- priority 1, 2 & 3 / Items 6) (N=117) Beds and 23 9 2 0 0 0 34 29 Bedding
Clothing 4 15 13 5 0 2 39 27
Furniture 3 7 3 5 0 0 19 11
Documents 5 1 5 2 3 0 17 9
Television 6 2 1 0 3 1 13 8
Fridge 3 3 1 0 1 1 9 6
Stove 1 2 2 7 2 0 14 4
54 The average amount for damaged household items was R1 831. Some of the damaged items could be recovered through repairs. In a situation where they cannot be replaced, victims either live without or wait for aid from friends or other social groups, like the Bryanston Methodist Church, which donates food parcels and blankets to disaster victims to help. Many respondents however, reported their inability to replace their damaged items as a result of the economic situation (high level of unemployment).
There is also the persistence of flood water within the households. On low slope areas, this usually takes a few hours to drain off, unless ditches are created, or if outlets are created in homes at the base of walls. Flood water may remain stagnant in and around the households within the low-lying areas without drainage points, a phenomenon known as ponding.
4.3.4 Evaluate resilience and adaptation
Most of the inhabitants of this township were moved into it; meanwhile others have found themselves there either wilfully for job searches or to claim RDP houses. With floods identified as a major natural hazard making life uncomfortable for them, the residents or households have adopted certain measures to reduce their vulnerability to flooding. These measures include: Lining their floors with plastic sheets before placing cement to avoid water seepage into their homes. Before taking this measure, some take a preliminary step to raise their floors to about 600 mm above the surrounding soil (Figure 18). Other households used sand bags to block runoff into their homes (Figure 19a). Though it was reported not to be effective during heavy storms as the sand bags would be swept off and cause more damage to their dwelling units. Placing pipes underneath their households to channel water out into others drainage systems or unto the streets (Figure 19b). Sinking a section within the dwelling where all water seeps and buckets are used to bail it out. They also raise places or use bricks and tins to raise valuable items like beds (Figure 19c), stoves, documents and even humans climbing on tables. Using concrete and cement to raise dwelling units and/or embankments before the house to stop water flow into their homes. Some created outlets at the rear of their houses so that any water entering their homes flowed out quickly.
55 Figure 18: Floor lined with plastic before cement (Photo credit: Ngie, 2011)
Figure 19: Flood adaptation measures in Diepsloot township (a) Sandbags to block runoff; (b) Pipes underneath dwelling units; (c) Raise furniture on bricks and tins (Photo credit: Ngie, 2011)
D19 If this place is identified as an unsafe area and you are given any option to relocate to a safe area, would you move? Some of the respondents reported to be willing to move from the area if it is identified as unsafe for human habitation. This is contradicted by
56 others who see it very convenient for them either because dwelling units were not within flood vulnerable sites (adjacent to water course, low-lying and low-slope areas). According to some respondents they were simply tired of being moved from one location to the other and feel possible solutions (strong dwellings and construction out of floodplains) could be applied to make the place suitable for human habitation.
4.3.5 Other hazard management aspects from local knowledge
D22 Is there any other issue(s) that your settlement is being exposed to in terms of other hazards? 93% of the sampled respondents answered in the affirmative and in naming them according to rank responses, they illustrated air pollution as the first natural hazard and water pollution as the second (Figure 20). Therefore, a majority of the households were aware of the vulnerability of this township to other environmental hazards like water pollution, waste disposal, air pollution and fires, which continually handicap a healthy life style in this community.
Many households were however, ignorant of policies to help reduce their vulnerability (98%) within this community. They also complained civic organisations and local government do very little to assist them in reducing vulnerability during flood events. This is because they only visit them during the events, unlike offering awareness campaigns and support before and after the events respectively.
40
35
30
25 Fires 20
Count Air pollution 15 Water pollution 10 Waste disposal 5
0 First Second Third Fourth Rankings
Figure 20: Other natural hazards plaguing Diepsloot township ranked accordingly
In order to probe disaster responses from local authorities and other social networks, many (95% of the respondents) denied ever receiving aid, with only 5% agreeing to have done
57 so. However, the next question requested not just their experiences but also observations on …the nature of disaster aid. This was in the form of groceries and/or food parcels, as reported by 83% of respondents. Other items such as money or new dwellings are rarely received. Respondents also complained the discriminative nature of distributing this aid. According to them, aid should be to every victim and not by magnitude of destruction. They also reported there is no clear order of distributing this aid, as some donors would do so by household heads and others on an individual basis.
A further investigation was conducted on where affected households will seek further aid after such devastating floods. With the poor response about receiving aid, most respondents did not find it necessary going to local government or other community leaders for help. To this they preferred other sources being relatives (family members), friends and nearby businesses (Figure 21).
Figure 21: Sources to seek aid by flood victims in Diepsloot township
4.4. Results on housing structures and vulnerability to flooding
The housing quality index for Diepsloot township demonstrated a majority of dwelling units being in a poor state as the predominant material for roofs and walls was metallic sheets (Table 10). The predominant material for the floor is cement but with different patterns of application. Some households use plastic sheets on the bare earth before placing sand and cement. Others use concretes to raise the floors, and some drill sections of the floor for flood water to recollect.
58 Table 10: Housing quality index for Diepsloot township
No. of % of Item Predominant material respondents respondents
Roof Plastic sheet or grass thatch 8 6.9
Metallic sheets 108 92.3
Tiles 1 0.8
Wall Metallic sheets (zinc, cardboard and wood) 74 64.3
Masonry (brick, cement and block) 41 35.7
Floor Mud and plastic sheet 9 7.8
Cement 98 85.2
Wood 8 7.0
Diepsloot township is made up of mainly informal housing (shacks). However, other housing types included private and state-constructed (RDP houses) units (Figure 22). These are made out of bricks, cement and metal sheets for roofs. These RDP households have been invaded by backyard shacks being constructed with metal sheets, cardboard paper and plastics sheets. It is considered by residents that those who live in well- constructed houses and RDP houses are safer than those in shacks. As a result, many have relocated from other townships around the city, like Lanseria, Alexandra and also rural areas, to apply and wait for RDP houses in Diepsloot township.
In order to test if there is a relationship between predominant wall material of dwelling and impacts of flooding (destruction of beds and bedding), a cross tabulation was conducted. This illustrated that informal structures (metallic sheets) experienced more losses than formal dwellings (with bricks) (Figure 23). For the cross tabulation, we re-coded the predominant material into two classes being combined (metallic sheets, cardboard, and others) and masonry (bricks, cement and concrete).
59 RDP houses with backyard shacks
Informal housing
Formal housing
Figure 22: Housing types in Diepsloot township (Extract from an aerial photograph of the City of Johannesburg, flown in 2010 by Southern Mapping Company (Pty) Ltd).
18 16 Beds and Beddings 14 12 First 10 Second 8 Third Count 6 4 2 0 Combined Masonry Housing structure
Figure 23: Comparison of predominant wall material and loss of beds and bedding during floods. (Combined = metallic sheets, cardboard, wood etc.)
4.5. Combined approach for flood vulnerability assessment The slope measurement indicated that Diepsloot township is situated in a generally low- lying area with some isolated high lands (Figure 24 & Figure 25). Sites A and B are outside of the banks of the watercourse or floodplain but are still vulnerable to floods after heavy rains, since the slope measurements are between 0° and 1.2°. Meanwhile areas C1 and C2 depicted in Figure 24 are within same measurement range (0 to 1.2°) as areas A and B, but differ in their layout planning – dwelling structures being informal and formal neighbourhoods respectively.
60 These selected sites corresponded with areas reported by local knowledge as prone to flooding (sections of Extension 2 were represented by site A; B is part of Extension 6 and 7; parts of Extension 1 and the Reception Area fall within C1; C2 is part of Extension 3 and Tanganani; E is within Extension 5; G was also a section of Extensions 2 and 4). Using this knowledge and GIS analysis, which measured the slope, there was a comprehensive mapping of flood at-risk areas in Diepsloot township (Figure 24). The floodplains were still identified as being exposed to flooding, though at different levels.
Sites D and F are within the floodplains and confluents of the seasonal streams as well as below the floodlines. Site E is on a higher slope (8.01 - 12.6°) yet within the floodlines and so vulnerable to floods (Figure 24). Residents from a section of Extension 2, reported flooding experiences, which was corroborated as being on a slope (site G being within the range of 4.6 - 6.6°) and affected by diverted runoff.
G
E
1000 m
Figure 24: GIS derived slope calculations over the Diepsloot township indicating flood prone areas – labelled A to G (discussed further in the text) (Ngie & Storie, 2011)
61 Figure 25: Groundwater seepage and retention within the floodplain from dwelling units in winter (Photo credit: Ngie, 2011)
62 5. DISCUSSION
Using the results obtained from the social survey and GIS analysis as evidence, this chapter presents a discussion of the findings. The conventional GIS mapping is discussed according to the floodlines. There follows a discussion of local knowledge concerning the causes of flooding, coping strategies, impacts and adaptation to flooding in Diepsloot township. The chapter subsequently evaluates the relationship between housing structures and flood vulnerability. With the identification of further vulnerable areas, there was need for a combined methodological approach using slope measurements to confirm local knowledge reports of flood-prone areas. It wraps up with an assessment of using the combined approach in flood vulnerability assessment not just for Diepsloot township but for the entire Gauteng City-Region.
5.1. Flood vulnerability in Diepsloot township
Using the conventional GIS approach to map areas within 1:50-year and 1:100-year floodlines, it was established that many dwelling units were located below these limits and hence vulnerable to flooding. Most of such dwellings were informal, and site permission would not have been approved in these zones if due permission had been sought. It is a cause of concern because these dwelling units are even damaged by ground water seepage during winter (Figure 25). An evaluation of the combined methodological approach in flood vulnerability assessment tested positive for Diepsloot township; the applicability of the methodology to the GCRO comprehensive survey of flood prone settlements within the Gauteng City-Region is discussed.
Mapping flood vulnerability in Diepsloot township interfaced closely with the concept of social vulnerability. Additional areas of flood vulnerability within Diepsloot township were identified through the social survey of local perceptions and experiences that had not been revealed through the GIS hydrological modelling. Such areas are flat areas (low slope) subject to ponding; and steeper areas, allowing damage from runoff due to poor drainage channels.
This chapter will discuss the implications of the evidence on flood vulnerability derived in the results chapter. These implications are to be linked with each objectives of this study. The discussion will be presented through the various steps (GIS hydrological model
63 mapping, social survey and the combined approach) that led to the creation of a comprehensive map of flood prone areas in Diepsloot township.
5.2. GIS hydrological floodline mapping
5.2.1 Flood vulnerability mapping using the 1:50-year floodline in Diepsloot township
Flood vulnerability mapping using the 1:50-year floodline indicated some households being exposed within this floodline. Road crossings and footpaths from one suburb to the other were also vulnerable to flooding since they were found within the wetland, without proper drainage infrastructure beneath the road surfaces. In Extension 5 in particular there were quite a number of households that were exposed to the 1:50-year flood risk.
5.2.2 Flood vulnerability mapping using the 1:100-year floodline in Diepsloot township
The 1:100-year floodline mapping exposed more households to this flood depth, mainly along the floodplains, encompassing both informal and formal developments. Secondary paved roads are also at risk to floods, especially in Extensions 2 and 6, as well as the N14 (Johannesburg-Pretoria) trunk road.
It should also be noted that the difference between the 1:50- and 1:100-year floodline is not much given the parameters used in the models. However, these floodlines might also be extended by floods if, as predicted, storms become more severe or more frequent as a result of global climate change [GCCOLP, 2011]. This would imply the floodlines need to be revised to reduce community and household vulnerability as a first stage of climate mitigation measures.
The mapping was based on floodlines developed through hydrological models which made the analysis limited to flood vulnerability only along floodplains adjacent to streams and seasonal drainage channels. Through local experiences, further areas were also identified as being vulnerable to flooding. They were situated on low-lying areas with minimal slope; alternatively, on steeper slopes with failed or inadequate storm water drains or diversions. Such areas were all scattered around the township, often lying outside areas demarcated as flood risks by floodline mapping. However, the use of a local knowledge approach complemented the hydrological mapping to produce a comprehensive flood vulnerability map.
64 5.2.3 Limitations to mapping
Storm drain failures and other localized causes like location of dwelling units are beyond the scope of hazard maps and must be addressed through preventative measures designed to reduce vulnerability [Brown & Damery, 2002]. This will therefore be discussed under the perceptions and experiences of the people as such feature cannot be represented on a vulnerability map.
The layout of dwelling units in Diepsloot township is so dense that it was not possible to count the number of units and so estimate the population exposed to flood events. This limitation to calculate potentially impacted populations can hinder disaster planning, preparedness, mitigation and recovery.
Spatial data such as the floodlines are represented in vector format (discrete polygons, not continuous) whereas the biophysical environment is not static. The artificially rigid borders displayed by these vectors does not allow for a refined, boundary ‘fuzziness,’ and areas of transition commonly associated with natural phenomena.
It should also be noted that whilst hydrologically innovative and robust models are available, they are poorly suited to real time application, are often not well integrated with spatial datasets such as GIS. Current systems also lack flexibility, customizability and accessibility by a range of end users [Al-Sabhan et al., 2003]. Data integration of a variety of environmental aspects, presentation of dynamic processes in GIS and cartographic modelling language (map algebra) are a tough challenge to be handled within any simple GIS system [Yanar & Akyürek, 2006] like the ArcGIS student license being used by the researcher. As an alternative for representing real world, the fuzzy logic approach has been introduced through FuzzyCell which is a system designed and implemented to enhance commercial GIS software, namely ArcMap [Yanar & Akyürek, 2006]. They concluded that the fuzzy logic approach may only contribute to a better representation and reasoning with imprecise concepts. Therefore such complex integration usually requires significant data programming in complex software and hardware, which was not within the scope for this study.
5.3. Local knowledge on flood vulnerability
Some respondents perceived that the geography of Apartheid has meant that “…poverty affected some people more than others and has become a factor that exacerbates flood
65 vulnerability within this township since housing layout is not planned nor well developed with drainage systems” (60+ male respondent, previously re-located from Alexandra). This socio-economic inequality has transcended from national through to community and household levels. Lower income or historically disadvantaged segments of population are often situated in more hazardous settings than others due to the historical consequences of political, economic and social processes. These differences are also glaring within informal settlements as would be noticed with various extensions in Diepsloot township. Residents living in squatter camps (Extension 1, Reception Area and others – backyard shacks) are seen to live in abject poverty, while their counterparts in RDP housing (Extensions 2, 5, 7) and formal housing live in better conditions, with some even living in affluence.
There is a relationship between flood vulnerability and social inequality within communities as reported by respondents. Hence for some, the nature of flood vulnerability is changing and intensifying, while their ability to cope has diminished since they lack resources to put their flood coping ideas into practice.
5.3.1 Causes of floods or flood vulnerability in Diepsloot township
It should be noted that the actual significance of some of these potential causes of flooding cannot be scientifically proven, but were locally perceived and include many drivers that can be dealt with by local action. Both informal dwellings and RDP households identified floods as a major environmental challenge that has affected many households (52% of respondents) within Diepsloot township. The respondents identified households situated on poorly drained areas (floodplains) to be more vulnerable to floods during both the summer and winter seasons (Figure 25 above and Figure 26). Other vulnerable households within this community included those on steeper slopes and those besides poorly constructed storm water drains. Dwelling units located lower than street level and low-lying areas were also identified as being vulnerable to storm water runoff. However, respondents also identified the fact that even within floodplains some households were not damaged as others, as a result of the structural strength of their dwelling units. In this case they identified units with protective walls and raised floors of predominantly concrete or cement to be less vulnerable than shacks built without solid flooring or foundations, made out of predominantly metal sheets and cardboard.
66 Figure 26: Construction within poorly drained areas in Diepsloot township (Photo credit: Ngie, 2011)
From the above, it would appear necessary to distinguish three types of flooding that occur in Diepsloot township, as identified through local knowledge: a) Flooding adjacent to water courses, considered as river inundation. It occurs after heavy rainfall, when water levels within courses may rise above the embankments. The water may then overflow into houses. b) Flooding as a result of enhanced filling from runoff diverted into low-lying, low- slope areas, and in structures below streets (ponding). c) Flooding of structures built on slopes, resulting from the diversion of storm water by higher-lying structures and infrastructure (in the absence of storm water drainage or diversion). Insecurity of land tenure combined with social and political factors have further mediated flood vulnerability in Diepsloot township. Due to insecurity of tenure, there was little or no community participation to influence or block policies that were perceived as harmful. This was reported by households especially in the Reception Area and Extension 1 as the reason for temporary dwelling structures, since they could be evacuated to other areas at any moment: “Why should we spend the little money we have on the house structure, knowing we can be evicted at anytime” reported 47 year old female respondent in the
67 Reception Area. She has been in this area for 11 years, trying to run a tavern business. But with no electricity, sales were not encouraging and during summer seasons completely stopped after heavy rains since the place became flooded. Furthermore, she could not even have a loan to restructure her dwelling as a suitable safe home and business site, since there are no documents that entitle her to the land. So she reported as her greatest desire that “…the government should just sign documents that will assign these stands to us as permanent, and then meaningful investment would be done to survive challenges”.
Most residents in this area had been evacuated previously from Alexandra to stands provided on an interim basis; dwelling units on these stands have become almost permanent, as some residents reported to have been there for over ten years, but with no further intervention from the municipality. Some households have remained within these conditions in the hope of eventually being assigned to RDP housing. While waiting for this free housing over the years, many households have remained in these insecure dwelling units (poorly constructed shacks), which exposes them to floods, and other hazards, such as fire.
As a result, these people find themselves located in the most vulnerable locations mentioned earlier and to construct dwellings comprised of inferior building materials. These informal dwellers lacked the capacity to undertake any flood mitigation measures. In contrast, those informal dwellers less seriously impacted had undertaken some flood mitigation measures, like using pipes to channel water away from their dwellings, using plastic sheets before cementing their floors and stabilising their roofs. In some instances dwellings had proved more resilient because the occupants had laid concrete floors that reduced ground water seepage, or raised the floor level by a critical few centimetres.
Since the informal dwellings were located in poorly drained areas (adjacent to the water course and low-lying) with high water tables, constructed of poor building materials in an often unstable manner, with a foundation lower than ground level, most of them were affected by flooding, in one or more of three dominant forms: (i) through seepage of ground water, (ii) runoff water; and (iii) rain water leaking through poorly constructed roofs. Runoff water also entered through the doors and in some cases rainwater also entered through walls.
68 Residents, crossing the central steam from one section of the township to the other on stepping stones, are also exposed to flooding during and/or after heavy rains. People especially children are reported to have been swept by floods as they attempt to use these foot path crossings (crossing from Extension 5 to 7) (Figure 27).
Houses within the higher slope areas also suffer from diverted storm water entering into the dwellings. Mostly affected are RDP houses within Extension 5 (site E), where residents have responded by building diversion embankments upslope of their structures. Furthermore, some backyard shacks have been constructed with doors facing the upslope of the hill, allowing storm water runoff to flow into the dwelling.
Figure 27: Crossing streams without bridges increases vulnerability of residents in Diepsloot township (Photo credit: Ngie, 2011)
The erosion scars along the streets in this area (Extension 5 and site E) are evidence of the high volumes and velocity of runoff. This is further proven by the sign post of Johannesburg Roads Agency (JRA) at this site warning residents of the dangers of storm water (Figure 28). This sign indicates that the authorities are aware of the danger posed to the residents staying within this location. It also is a reflection of the social inequality that instead of fixing the problem through the construction of proper storm water infrastructure,
69 the Council erects a sign to place the onus on the public, including young children who could not reasonably be expected to comprehend the meaning of the sign.
Figure 28: Johannesburg Roads Agency public notice on the danger of storm water drains in Extension 5 (Photo credit: Ngie, 2011)
However, informal structures were also identified as suitable in this area since occupants easily create holes on their walls to let flood water in and out! This measure, according to them, reduces the retention time and destruction within the households. It is therefore an adaptation measure emanating from local knowledge by the people within this settlement to live with floods.
Poor waste disposal is also a cause for concern, as it blocks storm-water drains, thereby diverting runoff into households (Figure 29). It was also reported by households that the waste along storm-water drains ends up in their houses when it floods. The issue of human waste and associated odours which may last for weeks after flooding within households was common experience. This is a health hazard to household occupants, especially of vulnerable groups like children and elderly (60+).
70 Figure 29: Waste dumping exacerbates flood vulnerability in Diepsloot township: (a) waste dumping into a storm water drain; (b) waste carried by water runoff from an informal dump across roads and into storm water drains (Photo credit: Ngie, 2011)
The root cause of vulnerability for RDP dwellers was more attributable to poor governance, reflected in poor regulation of building standards and inadequate communication between municipal and district departments. This could be summed as poor integrated planning of the township. The result was that houses were built lower than streets with no or very few drains, which were often blocked. In some cases, dwellings were built directly under the storm water drainage outlets, like in Extension 5. Furthermore, respondents reported all housing (RDP) construction projects were outsourced to private contractors and there seemed to be very little control over their activities (in terms of quality control and adherence to building standards). They are often not held accountable for using the cheapest possible building material and methods which contribute to the poor structural integrity of many of the RDP houses. A respondent in Extension 5 complained of his dwelling always being flooded during heavy rains since it was located on a slope along storm water drains. Another respondent in Extension 2 reported of leaks on his roof which causes damage to his property.
Apart from many people living in floodplains, river floods are further influenced through sealing of surfaces, due to dwelling units without open spaces between, and paved areas, which increase runoff, changing the hazard parameters and extending the flood prone areas
71 [Rauken & Kelman, 2010]. This is as a result of increase runoff volumes and diversions. Assets that were not originally placed in a flood zone could end up being exposed to floods due to later (unplanned) developments. Other human modification of the natural and built environments, generally through local decision making, contributes to this dynamic pressure that increases vulnerability. Building bridges, filling up stream paths, blocked drainage and vegetation clearing are examples of modifications of local surroundings that could inadvertently increase flood hazards.
The construction of dwelling units on natural storm water channel drains increases their vulnerability to floods (Figure 30). These channels have been used as informal waste dump sites by residents, thereby diverting the flow of water from these drains into homes. Residents as well as the authorities have not adhered to warning signs on storm water drains by Johannesburg Road Agency (Figure 28 above) which was placed as a result of the frequent deaths due to drowning. RDP houses and resulting backyard shacks have been placed adjacent to the warning sign post in Extension 5. Even with the construction of protective walls, the dangers of floods are still glaring through erosion scars left by runoff around these dwelling units (Figure 31). However, these dwellers rejected being interviewed by the research team, maybe for fear of being relocated or evacuated.
Figure 30: Construction of dwelling units on storm water drains in Diepsloot township (Photo credit: Ngie, 2011)
72 Figure 31: Construction of dwellings around storm water drains (Photo credit: Ngie, 2011)
Because RDP dwellings were poorly constructed and poorly sited with dwellings below street level and sometimes facing runoff tracks, they were affected by flooding. In cases where dwellings had to contend with proximity to storm water outlets, this resulted in runoff also gushing into households, like in Extension 5. The poor quality of construction, accompanied by the inferior quality of building materials, meant that rain water also entered through the cracked walls and poorly sealed roofs.
There also seemed to be a lack of awareness on how to reduce flood vulnerability on individual dwellings, especially among ‘new arrivals’ into the township. So they simply just ‘cope’ with the hazard by using buckets to catch leaking water from roofs or scooping the water out. Some dwellers carve out holes in the wall of their dwelling units to drain out water. This practice in turn makes them more vulnerable especially if heavy rains are received before the hole is repaired, as in the case where the second event occurred soon after the first.
5.3.2 Coping strategies to floods in Diepsloot township
Vulnerability is perceived as the concept that explains why people with the same level of physical exposure can be more or less at risk. Coping capacity and adaptive competence are then the variables that modify the vulnerability. In other studies, gender and educational characteristics played a role in vulnerability studies [Rayhan, 2010] but there was not a
73 significant relationship in this area as proven by the Pearson-Chi square test of the responses to Question A5 (which was re-coded by regrouping the classes for analysis) and Question C13.2 of the survey, p-value yielding 0.334 (being greater than 0.05). These characteristics were to be a force for the implementation of these coping strategies through the strength and skills needed. However, literacy levels were not too low in Diepsloot township, as 97% of respondents had some form of formal education. These educational levels were, however, insufficient for the skilled job market, thereby leaving them unemployed and in poverty.
Through the people’s perceptions, this study probed coping strategies as local initiatives being implemented and further adopted as measures to reduce flood vulnerability on households in Diepsloot township. They identified climbing on higher objects during flood events as a means to save both human life and property from being damaged. This was considered as a short term measure. Meanwhile, through evaluation of adaptation measures, respondents reported on various methods which could be applicable to the entire community in order to reduce flood vulnerability, rather than relocation or evacuation.
Respondents identified certain parts of Diepsloot township being entirely within floodplains (adjacent to the water course) and experience groundwater seepage throughout the year, even during the dry winter season. By this they could only live in such areas by implementing certain measures on their dwelling units to avoid the destruction of household belongings by groundwater seepage. While many identified raising structures around their dwelling units to avoid runoff into homes, this was only applicable for households away from floodplains. Because households within floodplains needed to line their floors with plastic before placing concrete and cement as well as raise their foundation to a critical height.
By probing the strength and successes of these coping strategies, respondents were asked if they would change these strategies when the next floods are anticipated or start. In affirming the successes registered by these strategies, 68% of respondents refused to change these strategies. This, according to them, is due to the successes recorded and also because as a result of poverty they would be unable to implement other measures. This implies poverty limited their capacity to reduce or mitigate flood vulnerability on their households.
74 5.3.3 Impacts of floods on the households in Diepsloot township
Also through the survey, flood impacts were identified which included physical destruction on dwelling units during extreme flood events such as the 2010/2011 summer seasons. In isolated incidents, households located close to the banks of the watercourse had their dwellings completely destroyed or swept off during by floods.
It was reported by respondents that damages to personal belongings always accrue during flood events. Some of the items identified by residents included furniture (beds, cupboards and couches), carpets, bedding and clothing. In some instances, residents reported loss of their valuable documents, such as ID booklets. With the hard lesson of not having these documents easily replaced by the government, they have become more conscious and keep documents in safe places (wrapped in plastic and placed within boxes on higher objects like cupboards).
Even though Diepsloot township is highly an informal settlement, the population still own valuable items to make their lives better, that if being lost in the event of a flood, disrupts their comfort. Prioritising the items lost by residents during flooding, respondents considered beds and beddings to be their most valuable. This was regarded in terms of their ability to replace and the usefulness of these items. The respondents also by priority ranked their clothing as second most valuable item usually damaged by flooding. The fact that respondents did not rank stoves as a highly valuable item was simply because it is relatively cheap (if compared with beds and clothing), and victims usually receive food parcels as emergency aid during flood crisis.
The prevalent indirect flood impact was on the health of children, with mostly respiratory infections such as flu and asthma. Pneumonia, colds and sinus problems, and arthritis worsened. Skin rashes occurred because the water remaining in the houses was contaminated by bacteria and insects; physical injuries sustained from slippery conditions; and high blood pressure from the stressful circumstances were not left out of their list. These were handled by victims through health units in and around Diepsloot, including pharmacies in Fourways.
For reasons of economic disadvantage, limited access to social and political resources, residential choices and evacuation dynamics are social factors that contribute to observed differences in flood vulnerability within Diepsloot township. This was glaring for
75 inhabitants of Extension 1 and Reception Area, as opposed to those of Diepsloot West and other extensions with RDP and other private formal houses.
Even though receiving aid specifically during flood events was considered a rare action (5% of respondents), overall respondents considered social networks including friends and family relations to be helpful during and after flooding (63% of respondents). They expressed their grievances with local government authorities for not showing concern with victims, and that they perceive the aid processed as heavily influenced by nepotism.
5.3.4 Flood resilience and adaptation in Diepsloot township
In order to evaluate adaptation measures, this study looked at the long term strategies employed by residents to reduce flood vulnerability through dwelling structures. This section was also meant to assist the researcher probe if residents were willing to be evacuated or relocated to other areas as a result of increased flood vulnerability. This evaluation was done using cross tabulations, for instance testing if as a result of past flood experiences, respondents would be willing to move out of Diepsloot township if identified as unsafe.
Those who came into Diepsloot township as a result of evacuations from Alexandra due to floods indicated their unwillingness to be evacuated if the area was identified as unsafe for human habitation. This could be interpreted as a result of past experiences to manage and cope with these flood events and reduce their vulnerability. It could also be as a result of just being tired of moving from one place to the other and avoiding such inconveniences.
Those who came into Diepsloot township from rural areas in search of better opportunities indicated their interest to be moved out of the area if identified as unsafe. This should be interpreted as hopes for a better life since conditions at Diepsloot township are not the best of their expectations for life in the city. Some of them came in without any clue on coping strategies or adaptation measures on dwelling units to reduce flood vulnerability, so their first experiences were devastating both physically and psychologically. In one instance, a respondent pointed out households within the floodplains as being ‘new arrivals’ who “will learn their lesson only during the summer season”.
However, most informal dwellers had to reconstruct a small or large part of their dwellings after major flood events. Resilience in this case was fairly available since residents would
76 be able to resettle, though with just the same conditions and awaiting the same dilemma during the next summer season, or even left in worse conditions that will expose them once more. This is further proven by their inability to replace items damaged by floods, since they lack capacity for resources to reduce their flood vulnerability.
The occupants of dwelling units adjacent to the water course and low-lying areas, like in the Reception Area, mostly those with informal dwellings, would relocate to relatives elsewhere around the city during flood events. For instance, after the 2010/2011 floods, shacks were damaged and occupants moved to places of safety but returned thereafter as soon as conditions improved, even with water still flowing besides their dwelling units. This was indicative of the fact that land availability for habitation was limited. Therefore, adaptive measures needed to be put in place to reduce their vulnerability to floods, being able to cope with limited land availability and such natural hazards.
These households vulnerable to flooding were usually considered to adjust after receiving aid, though only for a few days or weeks before they return to their former lifestyles. However, some vulnerable people or households especially in Extension 1 and Reception Area were moved or evacuated to the newly developed Extensions 12 and 13 where stands were provided. They again raised informal dwellings and live under unsatisfactory conditions of no basic services (water, sewerage, electricity, as well as no storm water drains). It is hoped the local government will maintain a planned layout to minimise vulnerability of the populace in this area. All the above measures indicate households in Diepsloot township could reduce flood vulnerability in-situ rather than through evacuation or relocation. However, they lacked the capacity in terms of information and resources to implement these measures appropriately and sustainably.
Local perception about flood vulnerability in this community was greatly acknowledged alongside other natural hazards like fires, air and water pollution. One hazard interconnected with floods in this township was identified as waste dumping in storm water drains. This was not shared by everyone as some perceive family wellbeing, socio- economic factors (especially poverty) and health conditions more pressing. According to this group of respondents “…floods are only recurring annually, unless for those on wetlands experiencing continuous groundwater seepage into their homes even during winter and so less worry about it”. However, many households generally did not show
77 many signs of flood preparedness and response, except for their coping strategies in a flood event and associated evacuations.
For flood vulnerability reduction, it is often argued that local authorities and a community’s own inhabitants should take the largest share of responsibility for implementation, because local conditions are often (not always) best known by the local authorities and the population, plus they should have a vested interest in their own community [Wisner et al., 2004]. This does not say that local communities provide the sole inputs, because local knowledge is not a panacea [Tibby et al., 2007]. But without local initiatives, interest and support, flood vulnerability reduction measures are not likely to succeed.
5.4. Housing structure and flood vulnerability Housing is a key necessity for the poor and indicators of dwelling quality reveal the vulnerability of impoverished households to adverse weather conditions [Parnell, 2004]. Parnell reports further that on a national scale, nearly half of all informal dwellings and more than one-third of traditional dwellings can be classified as vulnerable to environmental factors. This is a major cause for concern given the thousands of people inhabiting these areas within such structures.
Diepsloot township is an area with both formal and informal housing structures. While it would be considered by engineers that informal housing structures are more vulnerable to flooding devastation, local knowledge tries to contradict this in a way. According to residents, these structures can easily allow floodwater to flow through without staying within their units. They also find it easier to erect such structures within such areas prone to floods, since during flooding holes are created to direct the water to flow out.
However, this study discovered that housing structures also expose households to flooding. The cross-tabulation of housing structures and flood impacts did illustrate that households in informal structures suffered greater loss than those within formal units (private and RDP houses made out of bricks, cement and properly roofed with metal sheet). This was much of an issue because most of the informal structures had holes on the walls that allowed runoff to flow into the units, or had earthen floors upon which carpets are placed directly. The earthen floors suffered from flooding even during winter through groundwater seepage.
78 Housing structure is also strongly linked to flood vulnerability where within the same area prone to floods there are formal and informal housing experiencing different impacts. In areas C1 and C2 (Figure 24), there is a squatter camp (Reception Area and part of Extension 3), and formal neighbourhood (remaining part of Extension 3 and Tanganani). With respondents in the Reception Area lamenting from flood devastation in their households and entire neighbourhood, while those of the formal section of Extension 3 and Tanganani experience floods mildly on the streets, but not within their households. This they attributed to the strength of their dwellings through materials used and raised foundations but with shallow drainage systems.
Another factor that exposes informal structures more to flooding than formal ones is the lack of planning in layout. These structures are mainly built for temporary use and are not very strong, but might never be demolished. They are also built by ‘new arrivals’ into the area with no means to obtain strong materials and so will use whatever scrap metals or plastic around them for a shelter. Most of these structures have been erected on any available open space, without any topographical or geological knowledge - areas that had intentionally been left open in layout of formal housing developments.
Filling the stream banks with earth and construction waste narrows the channel and may cause inundation during heavy rains even on the higher lying embankment (Figure 32). The above scenario was experienced in Extension 5, where these fillings extended construction space while increasing flood vulnerability for residents on the other side of the stream, which is Extension 4. They have also started filling the floodplain and expanding channels into the stream whose disastrous effects would be experienced further downstream.
79 Figure 32: Filling stream paths in Diepsloot increases flood vulnerability (Photo: Ngie, 2011)
5.5. Combined approach for flood vulnerability assessment
The mapping of physical vulnerability of households using physical hazard assessment methods (floodlines) indicated dwellings were located below these limits hence being exposed to floods. These floodlines are calculated only along the established floodplains and exclude other flood prone or at-risk areas. The floodline mapping was complemented by a survey of people’s experiences and further corroborated by the slope measurement map. With the conventional GIS approach, flood vulnerable areas were identified along floodplains with the aid of the physical hazard (river). Local knowledge reported further areas outside of the floodplains but also experiencing flooding. The slope analysis was then done, which corroborated those areas subject to ponding or runoff. This combined map extensive areas of flood vulnerability in Diepsloot township that were based not only on the physical hazard but on other topographical and human induced factors.
5.6. Evaluation of the combined approach to flood vulnerability assessment
In order to test the hypothesis of this study, some distinctive criteria were set to demonstrate the combined approach as better than independent methods of flood vulnerability assessment. These criteria would include: practicality, cost, comprehensive identification of at-risk areas, and social engagement. Comparison of the baseline case with the combined method is made in Table 11, with further comment given in the following paragraphs.
80 Table 11: Comparison between physical floodline mapping and the combined flood vulnerability approach
Physical floodline mapping Combined flood Criteria (baseline case) vulnerability approach
Practicality YES YES Relatively small incremental Affordable YES costs Comprehensive identification NO YES of at-risk areas
Social engagement NO YES
This combined approach is practically possible within small and large communities since it does not require technical skills to apply. The research assistants and respondents easily understood the process and made substantial contributions. The community might know the risk and not approach adaptation properly. It would be practically more advantageous to the community if workshops are held after such research, with all coping strategies brought together with their potential benefits. Community workers could easily be used to tap local knowledge and convey adaptation measures that are more environmental friendly.
The study demonstrated the practicality with moderate resources within a limited time space (Section 3.8). The approach encompasses the cost of the conventional floodline method and the social survey. However, the relative cost increment is small as compared to the result which is more comprehensive mapping of at-risk areas and will safe more property and lives.
Risk reduction measures usually begin with identification of at-risk areas in order to properly manage and mitigate impacts. It is important to recognise the risks in a location and to make risk-informed decisions, including enacting vulnerability reduction measures where needed [Rauken & Kelman, 2010]. The starting point of risk identification is more effective with this combined approach since additional areas outside of the floodplains are mapped. This approach identifies more at-risk population and this aids in implementing adaptation measures to mitigate impacts.
Community engagement is a vital tool in climate change adaptation and strategic programmes. People’s perceptions then identified the adaptation measures to reduce this
81 vulnerability even within floodplains. Through the social evaluation such adaptation knowledge can be incorporated into the mapping process (Section 5.3.4). Also with local population involved means inexpensive and protective measures can be applied within vulnerable communities. It is therefore implementable, affordable and accessible.
The key to flood adaptation is not necessarily to avoid flood-prone locations entirely, because that might lead to further problems, such as construction on unstable slopes or construction that destabilises the slopes. This combined approach has proven that it is possible to reconstruct adaptive communities, without moving population out of vulnerable areas, using community knowledge that can be evaluated and presented to them after all at- risk areas are identified. The success of the combined approach for Diepsloot township as a case study proves that it could be applied in the larger Gauteng City-Region flood vulnerability assessment programme, to be carried out by the Gauteng City-Region Observatory (GCRO).
82 6. CONCLUSION AND RECOMMENDATIONS
This chapter draws conclusions from the discussion presented with the findings. It also reports on the answer to the overall aim with reference to the hypothesis of the project. It wraps up with recommendations regarding aspects that may require further research in order to improve flood vulnerability assessment as well as development of sustainable and climate adaptive communities.
6.1. Conclusion
The history of Diepsloot township as reported relates that the township was developed to provide temporary human settlement until necessary plans were implemented for a permanent township, but was later hijacked by unplanned dwelling units and other human interferences. The lack of planning has meant increased vulnerability not just to floods but to other hazards as a result of poor structures and layout of dwelling units. The dense population and socio-economic status of these residents has only exacerbated their vulnerability as daily survival is crucial. Therefore, no resources have been set aside to establish a sustainable community with strong housing structures.
Local knowledge of flooding experiences, causes of flooding, and coping strategies within this community were examined through a community survey. Flooding, which is not only natural but human induced, was considered a major environmental challenge by the majority (95%) of dwellers in Diepsloot township. Two major causes of flooding as reported by residents were the construction of dwelling units within floodplains adjacent to watercourses, and in other areas due to poor drainage systems. The second category is divided into two sub-groups - flooding of houses on slopes, due to diversion of runoff from upslope dwellings; and flooding of structures in flat, low-lying areas through ponding (aggravated by enhanced runoff from surrounding built up areas). According to residents, flooding is exacerbated by heavy and unpredictable rainfall.
Through conventional contour mapping, the 1:50- and 1:100-year floodlines (along water courses) were identified. Overlaying these floodlines on aerial photographs indicated that certain households in Diepsloot township were located within these floodplains. However, evidence assessed through the local knowledge survey indicated that there were additional areas vulnerable to flooding that were located beyond the GIS-assessed floodlines.
83 Subsequent slope measurement analysis indicated that these additional flood-prone dwellings lay either in flat low-lying areas, or on steeper slopes. This slope analysis corroborated the further areas which had been identified through local knowledge. Overlaying the slope measurements on an aerial photograph resulted in a more comprehensive map showing flood-vulnerable areas of Diepsloot township.
Housing structure, which was evaluated in terms of the predominant construction material, was also discovered to play a role in flood vulnerability. Most households found below the floodlines were later identified to be informal structures, made out of predominantly metal sheets. In flood prone areas beyond the floodlines, both formal and informal structures were vulnerable. However, the impacts of flooding varied with the different structures. This was proven by informal dwellers recording more damage to their units and to household items like beds.
The awareness of this situation in Diepsloot township has assisted the community to become active agents in their protection against flood disasters. They have proven to be proactive in developing coping strategies to reduce the hazard or acting in an emergency situation, rather than being passive players solely dependent on external (municipal) emergency services. It is often said change is the only constant in life and so too are socio- ecological systems. Therefore, humans need to learn to adapt to environmental changes. Resilience is a key to successful adaptation and sustainable living. The residents of this community proved to be knowledgeable in some aspects of coping strategies, even though implementation was often hampered by lack of full technical skills or adequate resources.
The hypothesis of a combined methodological approach for flood vulnerability assessment being better than the conventional GIS floodline mapping that is based on physical hazard assessment only has been demonstrated to be true (Section 5.6 and Table 11), given that the conventional mapping identified at-risk areas only within the floodplains in proximity to water courses. Incorporation of local knowledge into the flood assessment identified further areas subject to flood damage, in low-lying areas and on slopes, thus enabling a more realistic and comprehensive assessment of the actual hazards faced by this community.
Overall, this study proved the feasibility of using a combined physical and sociological approach to study flood vulnerability, as applied to Diepsloot township as a case study.
84 This combined method proved more robust and applicable within urban communities with both formal and informal housing structures. The combined approach could be implemented at modest cost and does not require advanced technical skills to be implemented. It could easily make use of community workers to convey adaptation measures and to tap local knowledge.
Through this study, it was proven that flood vulnerability assessment can not only be done using floodlines but a social dimension will complement it. The success of this pilot study has also demonstrated that such a combined approach in flood vulnerability assessment could be extended to other areas within the Gauteng City-Region, as part of the comprehensive survey of climate change disaster vulnerability currently (2012) being carried out by the Gauteng City-Region Observatory. There is a possibility for further investigation and refinement of this methodological approach developed in this thesis.
6.2. Recommendations
The study proved residents were not completely ignorant about floods but there is a need for public information campaigns. Their knowledge will be expanded and ascertained for instance that floods cannot be prevented, but preparation for such extreme events is vital in minimising adverse effects. This must be done in collaboration with the people’s perceptions as they are taught to ‘live with hazards’, while minimizing unnecessary risks such as placing dwelling units made of less durable materials on flood plains. Public involvement would imply risk acceptance, as well as provision by responsible agencies of greatly improved information about the hazards.
In order to improve the management of natural hazards like floods, it is necessary to focus mitigation and adaptation strategies on increasing the capacity of communities. This capacity will enable them to adapt and live with natural environmental changes and surprises. By so doing, communities have to be aware of the dynamic relationship between social and ecological systems in order to increase their capacity to deal with the potential impacts of natural hazards.
Fünfgeld [2010:156] identified among four key barriers to effective adaptation “…the integration of information about climate risk and vulnerability into local planning processes and development agendas.” Local knowledge will not just aid in adaptation measures which are less costly but also their engagement in the development of policies.
85 When this happens the above barrier is broken and a holistic approach in reducing risk of the populace to natural hazards like floods is established.
Town planners must therefore identify this well of local knowledge about flood vulnerability in communities and adaptation measures being implemented, especially on dwelling units, for the development of risk mitigated communities. This should be incorporated into city planning. In this way communities will become engaged in developing policies, thereby enhancing their capacity to reduce flood vulnerability.
Better risk prediction and more accurate real-time flood forecasts is another useful support tool to risk reduction. This forecast can be combined with engineering research to improve design and operation of flood reduction systems. By so doing, the goal of flood forecasting, which is to provide a reliable prevention mechanism to eliminate disasters and reduce the negative consequences of a hazard will be attain.
There is also a need for floodline developments to dwell on topographical factors as a whole and not just based along water courses. This basis of mapping flood vulnerability can actually mislead people to construct homes in other flood-prone areas. Therefore, a refined approach including local knowledge to generate comprehensive vulnerability mapping will serve as part of a preparedness plan to guide human settlement within flood prone areas, for general public safety and as a climate change adaptation measure.
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92 ANNEXURES
Appendix A: Survey on Flood Vulnerability Directed to Households within Diepsloot Settlement Area in the City of Johannesburg - Gauteng Province.
Dear Sir/Madam,
My name is Adeline NGIE, a Masters student in Environmental Management of the Department of Geography, Environmental Management and Energy Studies, at the University of Johannesburg. My minor dissertation which is titled, “A GIS APPROACH FOR FLOOD ADAPTATION ANALYSIS AND VULNERABILTY IN DIEPSLOOT, JOHANNESBURG” requires that I collect data from communities for better understanding of their perception towards flood vulnerability (the state of being exposed to the dangers of flooding after heavy rains). I am pleased you accepted to participate in this interview. Your contribution is highly appreciated and I wish to take this opportunity to assure you that I am committed to secure your privacy and confidentiality in as far as your responses are concerned. The information collected will be for academic purposes only and your name will not be mentioned.
The overall purpose of this survey is to draw out from respondents within households, their perceptions and experiences on floods, as well as their flood coping strategies. Respondents are also requested to provide information about the material of which their dwelling units are constructed. For their coping strategies, the research tries to find out how residents react during and after a flood event.
The individual information collected in this interview is confidential and will only be used for academic and related purposes. For each household, one questionnaire will be administered, to the head of household or a representative (either male or female participants).
Adeline Ngie, MSc Student
Contact phone number: 072 602 0353 Department of Geography, Environmental Management and Energy Studies University of Johannesburg Supervisor: Prof Harold J. Annegarn Contact phone number: 011 559 3927
93 (QUESTIONAIRE TO BE COMPLETED BY INTERVIEWER)
Place of interview (the extension within Diepsloot): ………………………
Type of dwelling unit in which you live, (Put chosen number in the box) (1) House; (2) Flat; (3) RDP house; (4) Informal structure (5) Others (Please specify)…………………………..
Date of interview (dd/mm/yy): ………………………… Time: …………………………. GPS Co-ordinates (degrees, minutes, seconds)…………………………………….. A Demographics (Put a chosen number in the box) A1. Gender of the head of the household/representative: (1) Male (2) Female
A2. Age of the head of household/Representative:
Age range Put a tick (√) 16 - 24 25 - 44 45 - 59 60 – above
A3. For how many years have you been staying here? ……………………………………… A4. Did you experience floods in the former area where you lived previously before moving to Diepsloot?
(a) (1) Yes (2) No (1) If ‘Yes’, how did you cope? (i) Evacuated14 (ii) Relocated15
A5. Highest educational qualification
(1) Degree (2) Diploma (3) Certificate (4) Matriculate (5) Grade 10 or 11 (6) Grade 8 (7) Others (Please specify)………………………………… (8) None of the above
14 Being removed from the area by the authorities 15 Moved by yourself to a new location
94 A6. Number of people within the household;
Age range (years) Number 0 -15 16 - 24 25 - 44 45 - 59 60 – above Total
A7. Any disabled (that can impair movement) members in your household?
(a) (1) Yes (2) No (b) If ‘Yes’ how do you manage with this person(s) during floods? ......
A8. Have you ever lost a family member(s) during any flood event? (a) (1) Yes (2) No
(b) Was(were) the family member(s)
Category Put a tick (√) where Number of deaths appropriate Children (0-18 years)
Disabled adult(s)
Adult(s) (19-59 years): Men
Women Elderly (60+ years) Total number of deaths
B. Housing Quality Index B9. Is your house/ dwelling unit (1) Rented (2) Owned (3) Others (Specify) …………………………………………………………………………….
95 B10. WALL (Predominant material of external walls) (0) = Wooden frame and plastic sheets (1) = Mud/dirt (2) = Metallic sheet (zinc, boards & woods) (3) = Masonry (brick, cement and blocks) B12. ROOF (Predominant material for roof) (0) = Plastics sheets (1) = Grass thatch (2) = Metallic sheets (3) = Tiles B11. FLOOR (Predominant material of floor) (0) = Dirt (mud) and plastic sheets (1) = Cement; (2) = Wood (3) = Bricks
C Flood Experiences and Coping Strategies C13. Has your household ever been damaged by floods? (1) Yes (2) No If you answered ‘No’ to question C13, proceed to answer section (b). (a) (i) If ‘Yes’, describe what happened and when did that happen (briefly)? ……………………………………………………………………………………. ………………………………………………………………………………………. (ii) How did you cope then? (1) Relocated (2) Evacuated (3) Rushed to safe areas (4) Climb on higher objects (5) Others (Please specify) ………………………………………………… (iii) List the articles/assets (from the most valuable as 1, 2…) that were destroyed by the flood. Rank Items Television Fridge Beds and Bedding Furniture Stove Clothing Documents Other (specify):
96 (iv) Were you able to replace the destroyed items after flooding? (1) Yes (2) No (v) Total estimated value to replace items (in Rands)…R……………………. (vi) Why were/weren’t you able to replace them? ………………………………………………………...... (b) (vii) If you answered ‘No’ to question C13 above, what do you attribute the fact that your household was not damaged by floods to? (1) It was not within the floodline (2) My dwelling was strong (3) Others (Please specify)………………………………………………….
(viii) What other indirect flood impact(s) (problems) did your household suffer? If any (1) Diseases (2) Hunger (3) Unemployment (4) Others (Please specify) ……………………………………………………………… (ix) How did you cope from those indirect impact(s) (problems)? (1) Aid from the State (2) Aid from NGOs/churches (3) Aid from Community (4) Aid from family members (5) Others (Please specify) …………………………………………….. C14. If the next flood comes, would you approach flood mitigation differently? (1) Yes (2) No (3) If Yes, what would you do differently? ...…………………………………………………………………………………… ……………………..……………………………………………………………… (4) If No, why not change your strategies? …………………………………………………………………………………… …………………………………………………………………………………… C15. What do you think is the major cause of flooding in your area? Number them according to the most important cause using 1 as the highest. Use n/a where you don’t consider the item as a cause. Rank Cause Construction within wetlands or low lying areas Waste dumping along water ways Increased runoff volumes from paved areas (surrounding developments) Blocked drainage systems Heavy rains All the above None of the above Other (please specify)
97 C16. Of the following flood coping strategies, indicate the ones your household adopted or can adopt as a way to cope with flood impacts. (Same instruction as with C15) Rank Coping Strategies Be Evacuated to places of safety Relocate to safer areas Building protective walls along river banks Building homes with durable materials Raising the settlement structures Do nothing and wait for neighbours and government to help Approach local businesses and structures of governance to help Others (Please specify)………………………………………………… C17. Why do you think coping strategies identified in question C16 above are/would be effective? ……………………………………………………………………………………………… ……………………………………………………………………………………………… D Locational Factors/decisions D18. Why is your household located here? ……………………………………………………………………………………………… ……………………………………………………………………………………………… D19. If this place is identified as an unsafe area and you are given any option to relocate to a safe area, would you move? (1) Yes (2) No (a) If Yes, where would you like to move to? ………………………...... (b) If No, why wouldn’t you move? .……………………………………………………………...... D20. In a household situation, who is likely to take the final decision to resettle and why is it like that? (a) Who? …………………………………………………………………………………………. (b) Why? ………………………………………………………………………………….. ……………………………………………………………………………………………… D21. What would you like to change in terms of the roles of taking decisions and household level initiatives? ……………………………………………………………………………………………… ………………………………………………………………………………………………
98 D22. Is there any other issue(s) that your settlement is being exposed to in terms of other hazards? (1) Yes (2) No If Yes, name them by rank: Rank Other Hazards Fires Air pollution Water pollution Waste disposal Others (Please specify ……………………………………………… D23. Are you aware of policies or laws meant to enhance flood coping capacity within this community? (1) Yes (2) No If ‘Yes’, what? …………………………………………………………………………………… D24. What role does the institution of chieftaincy, civic organization and local government play before, during and after flood? (a) Civic organization; Before……………………………………..…………………………………………. During……………………………………………………………………………… After………………………………………………………………………………….. (b) Local government; Before…………………………………………………………....…………………. During……………………………………………………………………………… After………………………………………………………………………………….. D25. Do other social networks including friends and relatives help during and after floods? (1) Always (2) Sometimes (3) Seldom (4) Never (5) Don’t know D26. Why do you think your household and community are exposed to flood disasters? (a) Household…………………………...... ……………………………………………………………………………… (b) Community………………………………………………………………………… ………………………………………………………………………………………
99 D27. What do you think should be done to reduce flood vulnerability (exposure) at the household and community levels? (a) Household level ……………………………………………………………………………………………… ……………………………………………………………………………………………… (b) Community level ……………………………………………………………………………………………… ……………………………………………………………………………………………… D28. (a) What is the nature of disaster aid you have received?
Aid items Place a tick (√) Food/groceries Medicines Clothes Bedding New dwelling units (place to stay) Money Others (Please specify) …………………………………………………………………………. (b) According to your experiences, how is it distributed in the event of a flood? (1) Through community leaders (2) Through household leaders (3) Individually (4) Others (Please specify)…………………………………………………….. D29. Do vulnerable (exposed) household(s) adjust after aid or are they left permanently vulnerable? (1) Always (2) Sometimes (3) Seldom (4) Never (5) Don’t know D30. Flooding is the major environmental problem in the area. (1) = Strongly Disagree (2) = Disagree (3) = Don’t know (4) = Agree (5) = Strongly Agree
100 D31. Neighbours would intervene if flooding occurred in the community. (1) = Strongly Disagree (2) = Disagree (3) = Don’t know (4) = Agree (5) = Strongly Agree D32. Settlement structures (durability of material and construction) expose households to floods. (1) = Strongly Disagree (2) = Disagree (3) = Don’t know (4) = Agree (5) = Strongly Agree
Thanks for your time. Siyabonga!
101 Appendix B: Floodlines
1000 m
Figure 33: 1:50-year floodline for Diepsloot (Mahlangu & Braune, 2010).
1000 m
Figure 34: 1:100-year floodline for Diepsloot (Mahlangu & Braune, 2010).
102