A Water Resources and Sanitation Systems Source Book with Special Reference to Kwazulu-Natal
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A WATER RESOURCES AND SANITATION SYSTEMS SOURCE BOOK WITH SPECIAL REFERENCE TO KWAZULU-NATAL: PART 3 by Peter Glen Alcock Submitted to the Faculty of Science in partial fulfilment of the requirements for the degree of Doctor of Philosophy in the Department of Geography at the University of Zululand KwaDlangezwa Promoter: Professor B.E. Kelbe Date submitted: January 1999 Part 3 contains the following: Chapter 10: A brief inventory of the surface water resourceslilBIII.ltI,i[mlJ! of Natal!KwaZulu :::::;::::::~::~:~-:=::;::::=:=: ::::::=:~:;:~;,:~::~:::::::::::'=:',:::': ·.~ '.J.f.:... ...·.••..•.•·.••. :..•.·•.·•·.••...•.•...••·.·••.·ilIDw.·•.•·.•·..· •.•.••.••·.••...• Chapter 11: Groundwater in Natal!KwaZulu ,. - ·······fj·imiJ:.:.,.:.:.:.:.,.,.;.,.:.~:.:.;.:.:.:...-.-.- ............•;.:<. < ••:.: :.:.:.:.:.;.:.:.;.;.;.:.: •••••••••••:~: Chapter 12: Water supply planning for infrastructure provision l!!!l~i.I.lr Each chapter has its own contents page!s. The pagination in Part 3 is consecutive. A comprehensive set of contents pages for the entire thesis can be found in Part 1. This thesis consists of the following: • Part 1. Chapters 1 - 5 • Part 2. Chapters 6 - 9 • Part 3. Chapters 10 - 12 • Part 4. Chapters 13 - 15 • Part 5. Chapters 16 - 17 • Part 6. Chapters 18 - 20 CHAPTER 10: A BRIEF INVENTORY OF THE SURFACE WATER RESOURCES OF NATALlKWAZULU An early description of the hydrological cycle... AD the rivers run into the sea; yet the sea is not full: unto the place from whence the rivers come, thither they return again. Ecclesiastes. 1:7 1 11111111111:1&11 CHAPTER 10: A BRIEF INVENTORY OF THE SURFACE WATER RESOURCES OF NATAUKWAZULU Contents 10.1 Introduction............................................. 6 10.2 Precipitation and runoff in Natal/KwaZulu ...••••....••....•...... 6 10.3 Rivers of NatallKwaZulu .•.•.........•........••...••.•....• 8 10.4 Drainage catchments and related data in Natal/KwaZulu ...•...•..•• •• 11 10.4.1 KwaZulu catchments. .••.•••••••..••••••••••••.••• •• 39 10.5 Homogeneous climate zones in Natal/KwaZulu ••••••••.....•••..•. 40 10.6 Runoff models .•.....•..•........••.•...•••.•.......... •• 42 10.7 Mean annual runoff in Natal/KwaZulu ..•••.••••.•••....• .• ...• •• 43 10.8 Median monthly runoff in Natal/KwaZulu ••.••....•••.....•...••• 43 10.9 The variability of monthly runoff in NatallKwaZulu ....•......•..•• .• 44 10.10 Water demand in NatallKwaZulu •...••...••..........••••.•••. 44 10.11 Sources of hydrological data ••••••.•.••.•••••••.....•.•....•• 55 10.12 Department of Water Affairs and Forestry hydrological gauging station reference system and network •..•....•••••.......•.•••••••• .• 62 10.13 Aspects of runoff data for Natal/KwaZulu ................................................ 84 10.14 Intemational rivers of Natal and environs ................................................ 86 10.15 Some voluntary river catchment and similar organizations in Natal/KwaZulu 89 10.16 Dams in NatallKwaZulu ..•.•...•.••••.......•.••.•.....•.• •• 92 10.16.1 Classification of dams for safety purposes ....•.••.•.•••• •• 92 10.16.2 Environmental impacts of dams and other works •••••••••••. 104 10.17 Some legal aspects of water in South Africa .•••••••••••••••••.•.. 114 10.17.1 Public and private water •••.•....••..•....•••.••••... 114 10.17•2 Riparian rights ..•••••••.••••••••..•....•••••••••.• 115 10.17.3 Use of water by local authorities. ...••..••••.....••••• .• 117 10.17.4 Use of water by industrial undertakings ••••.......•••••••• 118 2 Contents (continued) 10.17.5 Water restrictions ..••.•...•.•.•...•••..•••.••.••• .. 118 10.17.6 Water research levy .•••....•••.•.•••...•....•..•... 118 10.18 Some water control systems in Natal/KwaZulu ....•..•.•...•..••.. 119 10.18.1 Government water control areas ••.•.•..•...••.....•..•• 119 10.18.2 Government water schemes. ••....••.....•••...•...• .. 120 10.18.3 Government-assisted water schemes .......••.......•.•. 120 10.18.4 River diversions ....•...•....••..•..•..••...•....•• 122 10.18.5 Water boards .••........•..........•.....•........ 122 10.18.6 Irrigation districts and boards in Natal ..••.•.••.•...•..... 124 10.19 The provision of services in Natal/KwaZulu ....••••..••.....••.... 131 10.19.1 Local authorities and services in Natal ..••••.•.....•.•.. .. 131 10.19.2 Local authorities and services in KwaZulu ••..•.•...•..•... 146 10.19.3 Joint Services Boards in Natal/KwaZulu •...•.•.....•.....• 151 10.20 Civil defence (now known as civil protection) in Natal/KwaZulu •.•...••. 156 10.20.1 The severe weather watch service for South Africa ..••.•.... 161 10.20.2 The flood relief scheme for flood disaster areas .....••...... 162 Tables Table J1: Mean annual precipitation and approximate annual runoff density data for South Africa •..•..••••.... ••.••...•••.........•..• 7 Table J2: Water budgets for Natal/KwaZulu and South Africa •...•.•...•.. 8 Table J3: Distribution of the catchment areas of the 71 main rivers in Natal/KwaZulu •.•.•.•••••••.. ...•••••••....•..•.••.. •. 9 Table J4: Overall gradient distribution of the 71 main rivers in NatallKwaZulu •. 10 Table J5: Examples of rivers in Natal/KwaZulu with variable gradients (north to south) •...•....•..••.....•.•...•....•.•..•..•...•.. 10 Table J6: Mean annual runoff and other data for secondary drainage regions in NatallKwaZulu ••.•••••••••...••••••••• •...••..•.•.. .. 13 Table J7: Approximate location of Hydrological Research Unit (HRU) tertiary catchments in NatallKwaZulu ••...•.••.•••••.•.....•••.. .. 15 Table J8: Hydrological Research Unit (HRU) tertiary and quatemary catchments in NatallKwaZulu ..•.••..•••.•••••••..•.••.......•..•. 18 3 It;••~lii,iill Tables (continued) Table J9: Cross reference of Department of Water Affairs and Forestry secondary drainage regions and Hydrological Research Unit (HRU) quaternary sub catchments in Natal/KwaZulu .......••.............•.... .. 20 Table J10: Areas. mean annual precipitation and virgin mean annual runoff from Hydrological Research Unit (HRU) quaternary sub-catchments in NatallKwaZulu ......•••.•...... ..•......•........•. .. 23 Table J11: Runoff equations for the ACRU runoff regions of Natal/KwaZulu .... 38 Table J12: KwaZulu catchments as determined by Eksteen Van derWait and Nissen (EVN). 1990 .••.....•................•.•............ 40 Table J13: Homogeneous climate zones in NatallKwaZulu (north to south) ..... 41 Table J14: Mean annual surface runoff (natural MAR) and utilizable MAR for NatallKwaZulu in 1980 •...... ...........•..........•. .. 45 Table J15: Estimated mean annual groundwater abstraction for Natal/KwaZulu (106 m3 ) ••••••••••••••••••••••••••••••••••••••••••• 45 Table J16: Estimated mean annual return flow for Natal/KwaZulu (106m3) ..... 46 Table J17: Estimated mean annual total available water (MAR + estimated return flow + estimated groundwater abstraction) for NatallKwaZulu (106 m3 ) ...•..•................•.....•.........•... 46 Table J18: Estimated mean annual total utilizable water (utilizable MAR + estimated return flow + estimated groundwater abstraction) for Natal/KwaZulu (106m3)......•..•.•••...•........•.... .. 47 Table J19: Estimated mean annual intentional eV'!f.0ration and disposal of poor quality water for NatallKwaZulu (1 06m ) .•..•........••..... 47 Table J20: Estimated annual water demand statistics for NatallKwaZulu (106m3). 48 Table J21: Estimated annual water demand and surface runoff for South Africa and KwaZulu (106m3)...•••...................•.•....... .. 51 Table J22: Estimated annual water demand for NatallKwaZulu for 1980 and 2010 (106m3) ••••••••••••••••••••••••••••••••••••••••••• 53 Table J23: Types of gauging stations/points maintained by the Department of Water Affairs and Forestry. ..............•..•....•..... .. 63 Table J24: Department of Water Affairs and Forestry flow gauging stations in NatallKwaZulu. 1993 (south to north) •.......•.•...••.•... .. 65 lillllllllllll.'. 4 Tables (continued) Table J25: Number of stations with various lengths (years) of streamflow data for catchments of given size in South Africa. 1980 ...•.....•.•.• •• 85 Table J26: International rivers of NatallKwaZulu ............................................ 87 Table J27: Some voluntary river catchment and similar organizations in Natal/KwaZulu. 1993 •••.....•••...•.••••.........••..• 90 Table J28: Some relevant data on selected dams in NatallKwaZulu •..•••...• 93 Table J29: Size classification of dams with a safety risk ........•..•....•. 101 Table J30: Hazard potential classification of dams with a safety risk •.....•.. 101 Table J31: Category classification of dams with a safety risk ...•......••.. 102 Table J32: A simplified form of the environmental matrix used by the International Commission on Large Dams. with respect to project activities .••• .. 106 Table J33: Actions and environmental effects of water projects (according to the environmental criteria of the International Commission. on Large Dams) ••......• •. .•...•.•••.•..•••••........•.... .• 107 Table J34: Components of the environmental impact assessment matrix for the proposed Muzi Pan irrigation scheme ..••..•••...•••.•....•• 110 Table J35: Govemment water supply schemes owned and administered by the Department of Water Affairs and Forestry or administered by Umgeni Water in NatallKwaZulu. 1993 ..•.•..•....••••........•••• 121 Table J36: Irrigation districts in Natal. 1993 ••.•.•..-.•.......•...•.••• 125 Table J37: Irrigation boards in Natal. 1993 .•••.••...•••••.........••• 127 Table J38: Some urban areas in Natal. 1993 .••.••.•.•.•.•.••.•.••..•• 132 Table J39: Administrative