Feasibility Study of the Potential for Sustainable Water Resources Development in the Molopo-Nossob Watercourse: Groundwater Report
In view of the ORASECOM agreement the status and development potential of groundwater in the international river bason of the Molopo River drainage system has been examined.
It involved the following:
- A study of reports from the Department of Water Affairs and Forestry of South Africa on substainable groundwater explitation over a number of years.
- Information contained in the regional presentations of the surface water report.
- The impact of the groundwater exploitation on the base flow of the river systems and their periodic floods which is critical for the sustained utilisation of the groundwater recharge in close proximity of river channels in the semi- to arid parts of the Kalahari.
- The regional picture of the potential of exploration methods to locate new groundwater resources.
- A regional evaluation of the potential of groundwater in relation to the average annual rainfall.
It is clear that there is good correspondence between the regional straem density of the drainage areas (see Figure 1-1) and average annual rainfall (Figure 1-2) although the rainfall over the central Kalahari area is in fact controlled by the stationary stable high-pressure systems over the central area. Ground-water schemes that have been successfully explited for irrigation e.g. from the granite aquifers in the Coetzerdam-Louwna area (Botha 1992 and 1995) and that of the dolomitic aquifer at Tosca-Vergelee by Van Dyk (2005) were assessed in greater detail. In addition the extent of irrigation developments in the dolomitic aquifers of the upper Molopo and Kuruman and their impact on the recharge which substains the flow of major springs has also been put under scrunity. The ground-water development in the Molopo drainage occurs mostly in the upper reaches of the drainage system where the recharge is the highest (see Figure 1-3).
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