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43 10.7 Mean annual runoff in NatallKwaZulu* The mean annual runoff (MAR) in NatallKwaZulu varies from less than 50 mm in the north east, to over 800 mm in the Drakensberg. If the 100 mm MAR is used as a threshold, then East Griqualand and almost the entire northern half of the province has relatively limited surface water resources. Some difficulties accordingly, may arise with longer term economic development in the northern half of the Tugela Basin, unless water is imported from further afield. The most severe shortage of surface water is found in the area bounded by Louwsburg, Ulundi, Mtubatuba, Ndumu and Ingwavuma. A large portion of the latter region produces an MAR of less than 50 mm, with a significant area yielding less than 15 mm MAR. For the north eastern part of NatallKwaZulu where data are non existent, Schulze (1984) estimated that the MAR would be less than 15 mm and certainly less than 50 mm. 10.8 Median monthlv runoff in NatallKwaZulu Schulze (1984) found that there are considerable variations in runoff produced in different parts of Natal/KwaZulu in all months of the year. With the beginning of the rainy season, marked increases in runoff are evident during November and December. Over much ofthe province the highest flows occur during January to March, with the Drakensberg area 'yielding in excess of 60 mm of runoff in each of the months, January to March. The summer runoff in most other parts of NatallKwaZulu is a steady 5 - 10 mm per month, with the north eastern part of Natal/KwaZulu producing less than 2,5 mm of runoff. It should be noted however, that during seven months of the year, the north eastern region produces less than 1 mm of runoff. Minimum flows in NatallKwaZulu occur during August and September when most parts of the province yield less than 1 mm, with only a few isolated areas producing more than 5 mm of runoff. * Discussion based on Schulze, R.E., 1984. An assessment of the surface water resources of Natal, Natal Town and Regional Planning Commission Report, VOl 63, Pietermaritzburg, 44 p. and map. (Mean annual runoff was converted into a depth equivalent in mm for the purposes of the original discussion, by Schulze (19841). Runoff data for individual rivers in Natal/Kwazulu are presented in the chapter on -estuaries·, elsewhere in this publication.
111I111'llll1JII 10.9 The variability of monthlv runoff in Natal/KwaZulu 44 An importanttrend observed by Schulze (1984) is that there is a high degree of variability of runoff for any given month, in most parts of NatallKwaZulu. The variability is greatest in the north east and to a lesser extent in the north west during the months October to April (the period of greatest runoff production). The Tugela catchment in January, the Mfolozi Valley in February and the Drakensberg in August and September, all have a high runoff variability. Natal/KwaZulu, of all the provinces, has the lowest runoff variability and is in general known as the "Garden Province". For a discussion on drought runoff sequences in South Africa, see inter alia Midgley and Pitman (1969)*. 10.10 Water demand in Natal/KwaZulu With the runoff data in mind, the following section provides information relating to water consumption and demand, firstly for primary drainage regions W, V, U and T (Tables J14 J20). Overall demand statistics for South Africa and KwaZulu (Table J21l, and for NatallKwaZulu as a region (Table J22) are then outlined. Data in Tables J14 - J22 have been rounded off to the nearest whole number. Minor discrepancies may therefore be apparent. * See Midgley. D.e. and Pitman, W.V.• 1969. Surface water resources of South Africa, HRU Report No. 2/69. Hydrological Research Unit. University of the Witwatersrand, Johannesburg, 128 p. See also, Zucchini, W. and Adamson, P.T., 1984. Assessing the risk of deficiencies in streamflow, WRC Report No. 9112/84. Water Research Commission. Pretoria. 41 p. + app., as well as Zucchini, W. and Adamson, P.T.• 1984. The occurrence and severity of droughts in South Africa. WRC Report No. 91/1/84.198 p. + app. and maps. and Appendix 6. WAC Report No. 9111/84(AI. various pages. Water Research Commission, Pretoria. See in addition, Schulze. R.E.• 1979. Hydrology and water resources of the Drakensberg, Natal Town and Regional Planning Commission Report. VOl 42, Pietermaritzburg. 179 p.
Page 1: A WATER RESOURCES AND SANITATION SY
Page 4 and 5: Contents 1 11111111111:1&11 CHAPTER
Page 7 and 8: lillllllllllll.'. Tables (continued
Page 9 and 10: 11111111];11,,11. 10.1 Introduction
Page 11 and 12: Table J2: Water budgets for Natal/K
Page 13 and 14: Table J4: Overall gradient distribu
Page 16 and 17: 13 111.IJJ1111111 (when runoff: rai
Page 18 and 19: Table J7: 15 Hi) A small part of Kw
Page 20 and 21: 17 1\11••111;[11. Table J7: App
Page 22 and 23: 19 TableJ8: Hydrological Research U
Page 24 and 25: 21 11111••111111111 TableJ9: Cr
Page 26 and 27: 23 Table J10: Areas. mean annual pr
Page 28 and 29: 25 1111III1I11,rllll Table J10: Are
Page 40: 37 Table J10: Areas. mean annual pr
Page 43 and 44: IlfllllllllllJJilll 40 Table J12: K
Page 45: 10.6 Runoff models 42 Models are no
Page 52 and 53: 49 lil11l1tllll;lllll Table J20: Es
Page 54 and 55: 51 Table J20: Estimated annual wate
Page 56 and 57: 53 Table J22: Estimated annual wate
Page 58 and 59: 55 Ijlllltl1llflll (ii) Considerabl
Page 60 and 61: 57 large catchments data. The Centr
Page 62 and 63: 59 1111111111111' KwaDlangezwa, 283
Page 64 and 65: Other reports 61 Research Unit, Dep
Page 66 and 67: 63 1IIIIIE1111Elfl Id} The rest of
Page 68 and 69: 65 Table J24: Department of Water A
Page 82 and 83: 79 Table J24: Depanment of Water Af
Page 84 and 85: 81 Station closed Station closed U2
Page 86 and 87: 83 Station Drainage region Station
Page 88 and 89: 85 Table J25: Number of stations wi
Page 90 and 91: 87 iI11J111!!ltllllil equal share i
Page 92: 89 Source: liI After Anonymous, 198
Page 95: 111111111111111 92 boards (discusse
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Table J28: Some relevant data on se
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IDIIIIIDII':1111 98 (ii) The co-ord
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100 the respective departments at P
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1IIIIIIJIII.i1 102 Table J31: Categ
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104 10.16.2 Environmental impacts o
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Table J32: 106 A simplified form of
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1111111111111 108 Table J33: Action
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110 There is a growing South Africa
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112 Attention has also been focused
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114 10.17 Some legal aspects of wat
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116 time (mean exceedance flow), du
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IIII.IIWIIIII 118 10.17.4 Use of wa
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1[lIlIIIIIIJ. 120 Government dams,
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10.18.4 River diversions 122 Depart
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124 10.18.6 Irrigation districts an
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111(11111:41m'l 126 Table J36: Irri
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Table J37: Irrigation boards in Nat
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Tabla J37: Irrigation boards In Nat
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133 Table J38: Some urban areas in
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135 Table J38: Some urban areas in
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Table J38: 137 Some urban areas in
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139 Source: (i) After Ardington, E.
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141 i111_1illll1l noted above!. are
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143 (ii) The Directorate of Land an
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145 1111111111111 the Board will as
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147 Table J40: Administrative regio
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149 111II1.llllIf:J Government Noti
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151 111I.lIllllil1 Government agenc
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153 Table J43: Joint Services Board
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156 Source: (i) After Jenkin, F. (e
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158 Chief Directorate: Administrati
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Source: See also: Note: 160 Afterth
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162 off low - responsible inter ali
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11111.'.111:11111 164 If it became
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tlll••••I:IB11 NOTES: 166
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Contents 167 CHAPTER 11: GROUNDWATE
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Tables 169 Table K1: Some geologica
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174 Bate, 1992}*. The use of water
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176 X313, Pretoria, 0001; as well a
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179 a particular site, then a stati
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181 111...1[111 of streams and rive
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183 good. with a total dissolved so
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(iii) Holocene sands lQuaternary) 1
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187 Table K1: Some geological forma
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189 fault-bounded blocks, although
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191 11.6.4 Aquifer characteristics
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193 coarse and the latter, fine and
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195 111.BIII!I!111 The yields of bo
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11...,].11 198 11.7 Methods of grou
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201 11...11111 Table K3: Methods of
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203 boreholes are drilled for both
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205 1111111111'.1 3838. The borehol
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207 11.11 Standards applicable to t
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(a) Gravity springs 209 Gravity spr
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Table K4: Spring discharge in the V
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214 Table K5: The number of ephemer
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JJI...lllJll 218 (h) Some of the wa
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i'•••liDl Group E: Pure water
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222 Bond, Van Wyk proposed the foll
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1[11....11.,1 224 (b) Chlorides are
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226 Source: Edwards, T.J., 1989. Pe
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228 also obtainable from the Ground
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Ill1••lll1l 230 • Hofkes, EH.
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232 • Vegter, J.R., 1995. Groundw
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234 • Meyer, R. and Godfrey, l.,
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Springs 236 • Africa Co-operative
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NOTES: 238
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239 CHAPTER 12: WATER SUPPLY PLANNI
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12.1 Introduction 241 111'1&111111
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243 rilliltl.'ll water consumption
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Table L2: Cattle 245 study of reduc
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Note: (j) (ii) (iii) 247 Animal wat
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249 111111:llllltJI Source: After A
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1111111118.1 252 Table L4: Some per
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lillll.'.II' 254 high income. Iow d
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* 256 to obtain. Difficulties inclu
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1111...11 (iii) 258 Home Glasson Pa
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260 Table L6: Some typical domestic
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* ** 262 are in agreement with cons
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Table L7: Some South African indust
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Table L7: 267 Some South African In
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Table L7: 269 Some South African in
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Table L7: 271 Some South African In
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Note: (i) (ii) (iii) (iv) (v) (vi)
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276 concentrate on the provision of
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278 Table L8: RSA-KwaZulu Developme
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Table L9: 281 RSA-KwaZulu Developme
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Table L9: 283 RSA-KwaZulu Developme
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286 the Green book, namely, Anonymo
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IIIRlmlllillS 12.4.2 Durban Metro W
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291 design phase of projects. Any a
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294 Table L12: Some extant water wh
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11111111111911 296 • Energy Resea
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299 11111111111111 Table l13: Speci
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301 Table L13: Specific training ag
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304 Road and Umlazi (Durban); Pinet
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307 Table L14: A spatial typology o
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310 Table L15: A typology of social
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1111111..11 312 Table L15: A typolo
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315 114,[llll1\'1 Table L16: Some s
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317 Table L18: Mean household size
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319 Illil;JJtllllll Table L19: Exis
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321 Table L19: Existing housing del
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323 1IIIi!:lil.'11 a month, and a s
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NOTES: 325
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