A pre-impoundment study of the biological diversity of the benthic macro-invertebrate fauna of the Sabie-Sand River system

Bibliography: p. 177-205.The Kruger National Park (KNP) in the Eastern Transvaal provides a classic example of the potential conflict of interests between the industrial, agricultural and domestic sectors and conservation. The KNP is situated on the north-eastern border of South Africa and receives the flow of six rivers (Figure 0.1), all •of which originate outside the jurisdiction of the Park authorities. Thus, there are demands for water outside the boundaries of the KNP from other sectors of South Africa, as well as several self-governing states that have been set up as political entities within South Africa (see Chunnett, Fourie & Partners 1987, 1990). Due to human development •of catchments there has been regulation of these rivers, which are rapidly changing in terms of their flow regimes. (O'Keeffe. & Davies 1991). For example, the Letaba and the Luvhuvhu rivers have both changed from perennial to annual flow regimes (O'Keeffe & Davies 1991), a condition which is detrimental to the maintenance of river ecosystem functioning, while the Crocodile River has been regulated to an almost unvarying flow of ca 5m3 s•1 (O'Keeffe & Davies 1991). Recognising the need to address the problem of water allocation to the KNP, the Department of Water Affairs (DW A) convened a workshop on minimum flow needs for the environment in 1987 (Bruwer in press). Although tentative values were suggested for minimum flows, the value of the workshop was its recognition of the need for more research into the problem. Such research is currently being undertaken under the auspices of the multi-disciplinary KNP Rivers Research Programme. The goal of the programme is to " ... develop the means to predict the impact on the KNP river systems of changing flow regimes and water quality as the basis of a protocol for managing the• allocation of water for ecological purposes" (Kruger National Park Rivers Research Programme 1990). One of the studies initiated within this programme was a pre-impoundment study of the Sabie River, including its main tributary, the Sand River, which together are referred to as the Sabie-Sand River system