Pre- and post-impoundment studies (1978–1982) in the Volta River below the Akosombo Dam with particular emphasis on the microbiology

Abstract

A four year's survey of the Volta River below the Akosombo Dam to determine the distributional pattern and activities of different bacterial groups during pre- and post-impoundment of the river at Kpong is reported. The bacterial numbers were high and showed variations in all the stations. Relatively low bacterial numbers were observed in the upper reaches. The different bacterial groups followed approximately the same pattern over the entire length of the river. Industrial and domestic wastes slightly affected the quality of the water. The entire system was well oxygenated. During pre-impoundment studies the oxygen condition improved as the water flows downstream. Early post-impoundment studies showed a decrease in dissolved oxygen concentration around the middle reaches and an increase below the Kpong Dam. An emergence of Ceratophyllum demersum, Potamogeton octandrus, Vallisneria aegyptica and aquatic snails, which carry bilharzia parasites, was observed in the Kpong Headpond during post-impoundment studies. There was an extensive growth of submerged aquatic plants in the lower reaches.