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liI1'''.llliI11
Table J1: Mean annual precipitation and approximate annual runoff density data for
South Africa.
Province/country Mean annual precipitation Approximate annual
(mm) runoff density
(m 3 km- 2 )
NatallKwaZulu 878 135200
Transvaal 647 41 100
Orange Free State 590 25900
Cape Province 360 30636
Swaziland 865 125900
Lesotho 848 150900
Source: After Van Robbroeck, T.P.C., 1983. Address, In: Pegram, G.G.S. (ed),
Natal's Water Resources: the Future, Proceedings of a Symposium, 12
October 1983, University of Natal, Durban, p. 4 - 35 (including discussion
of the paper).
Note: (i) Schulze, R.E., 1979. Hydrology and water resources of the
Drakensberg, Natal Town and Regional Planning Commission Report,
VOl 42, Pietermaritzburg, 179 p., refers to a mean annual rainfall of
927 mm for NatallKwaZulu. The lowest rainfall areas in the province
still receive approximately 150 mm y'l more than the mean annual
rainfall over South Africa (including NataIlKwaZulu). which is only
485 mm. Readers requiring climatological data for other countries
in southern Africa should examine the following as a first
approximation: Anonymous, .1984. Agroclimatological data for
Africa, VOl 2: countries south of the equator, FAO Plant Production
and Protection Series Report No. 22, Food and Agriculture
Organization of the United Nations; Rome, 13 p. + app. (The
publication - which is available in the Life Sciences Library, University
of Natal, Pietermaritzburg - contains tabulated data for individual
stations in the various countries).
(ii) About 25% of the runoff of NatallKwaZulu originates at an altitude
above 1 400 m (namely, in bioclimatic groups 4 and 5 . see the
chapter on catchments, elsewhere in this publication).