Certain sites have already been selected for development in the 1980s and financing is either approved or about to be arranged. These are shown in Table 1. The list is not entirely complete.
As part of its review of financing requirements until 1995, the World Bank has made a review of each of forty-five countries in East and West Africa, showing projected load growth, the need for (and cost of) system studies, and possible future sites for hydro development. Load growth in terms of installed capacity1 has been extrapolated to the year 2000 and the projected loads for the years 1990 and 2000 have been shown alongside the actual 1980 load in Table 2. In general, it should be noted that in most cases, the countries concerned have already embarked on a programme of hydro development, whether or not they have oil reserves or prospects of finding them. Only the countries with limited potential for hydro development are looking to their coal, oil, or geothermal resources as substitutes.
Surface area is the basic parameter used for predicting the fisheries potential in new reservoirs; however, information on surface area is lacking for many of the new reservoirs. By using another relationship, however, as shown in Table 3, it is possible to arrive at an estimate of the new reservoir area in 1990 and 2000. Table 3 was prepared by combining the data of Bernaczek (1984) and data found elsewhere, to arrive at a ratio between total installed capacity in megawatts at a number of existing reservoirs, and total area of the reservoirs. All reservoirs over 100 km2 in area with data on installed capacity were considered. This ratio was 1 to 4 for all reservoirs. Dividing them into two groups, one of over 500 km2 reservoir area and one of less than 500 km2, we arrive at the same ratio for each, so it appears to have some validity for African reservoirs whether large or small, providing the group considered is large enough. There is a large variation with individual hydro developments, however, so it has no validity in predicting the area of a single reservoir.
Thus if we take the figures of Table 2: 10 224 MW installed in 1980, 21 044 MW installed capacity in 1990, and 36 535 MW in the year 2000, we have a proposed actual growth of 10 820 MW from 1980 to 1990 and another 15 491 MW by the year 2000. Multiplying these by the factor of 4 derived from Table 3 data, we have 43 280 km2 of added reservoir area by 1990 and 61 964 km2 by the year 2000. In other words, using these data the prediction is that the hydro power presently installed, and the reservoir area, will double in the ten years to 1990, and that total will almost double again in the ten years 1990 to 2000, as shown in Curve A of Figure 1.
However, we are now over one third of the way through the decade 1980 to 1990, and a first check on this prediction is available from Table 1 data. This shows that 3 019 MW have been approved for financing or are shortly to be approved. Most of this construction will be completed by 1985 to 1987. It would be rather optimistic to expect that the total for the 1980s will be any more than double this amount, or 6 000 MW. Therefore the adjusted prediction is based on this latter quantity, 6 000 MW equivalent to 24 000 km2 of reservoir area, as shown in Curve B of Figure 1.
There are two reasons for being conservative in our estimate. First, how sure are we of the relationship between reservoir area and installed capacity? We have another check on this from Table 2. There we have the total installed capacity in 1980 for the forty-five countries of Africa, 10 224 MW. The addition of Egypt and the other countries of the Mediterranean together with South Africa will make this total close to 12 000 MW for a total area from Bernaczek (1984) of 38 604 km2, or an overall ratio of 3.2 to 1. Considering that some reservoirs have inevitably been omitted from Bernacksek's total, this is considered to be a conservative figure. But using this ratio, the additional reservoir area works out to 34 624 km2 to be installed by 1990 and 49 571 km2 by the year 2000, based on the World Bank prediction with 1995 data extrapolated to 2000 as explained. These estimates are between the two extremes shown in Figure 1, Curves A and B.
The other reason for being conservative in our estimate was outlined above, that is, the difficulty the World Bank is experiencing in obtaining funds. We can only speculate on the effect of this on the future hydro programme in Africa, but it would seem proper to moderate our estimate for this reason.
Therefore, the best estimate of growth of reservoir area is based on the 6 000 MW noted above, giving an additional area of 24 000 km2 in the period to 1990 and another 8 000 MW or 32 000 km2 from 1990 to 2000, as shown in Figure 1, Curve B.
Table 4 gives a country by country review of the sites most likely to be developed by the year 2000. This is a most useful table and these sites should be closely monitored from the fishery point of view because it indicates where there is priority for planning for the development of reservoir fisheries.
