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The distribution of the catchment areas of the 71 main rivers in NatallKwaZulu, is outlined
in Table J3. Approximately 50% of the catchments are less than 40 km 2 in extent. Six
of the rivers in NatallKwaZulu are longer than 200 km, while 22 rivers are less than 10 km
in length, with 39 rivers less than 20 km in length. Nine rivers rise at an elevation greater
than 1 000 m, 22 rivers rise at an elevation of more than 500 m, with 66 rivers rising at
an altitude of more than 100 m. The overall gradients of the rivers in Natal/KwaZulu are
generally steep (Table J4). Such gradients however, are variable along the length of the
rivers and especially along the lower reaches. A few examples to illustrate this trend are
provided in Table J5.
Table J3: Distribution of the catchment areas of the 71 main rivers in NatallKwaZulu.
Area Number of catchments Percentage
(km 2 )
1 - 10 8 11
11 - 20 16 23
21 - 50 15 21
51 - 250 13 18
251 - 500 4 6
501 - 1 000 7 10
1001 - 2 000 1 1
2001 - 4 000 2 3
4001 - 8 000 3 4
8001 - 16000 1 1
16001 - 32 000 1 1
Source: After Anonymous, 1990. Hydro factors affecting siltation in the lower
reaches of Natal/KwaZulu rivers, CSIR Report No. EMA-D 9006, Division of
Earth, Marine and Atmospheric Science and Technology, CSIR,
Stellenbosch, 22 p. + app.