Spatial variation of the Akosombo hydroelectric power dam and its effects on downstream water quality, people and living organisms

Abstract

The Akosombo Hydroelectric Power Plant (AHPP) is one of the largest man‐made lakes in the world. The impact of the dam after its construction on living organisms and people is not known. This paper offers new insights into our understanding of how the lake affects water quality for living organisms and people living downstream of its tailrace at different spatial levels. Water samples were collected to determine physicochemical and bacteriological parameters at fifteen strategically chosen sampling points. The data were analysed in the laboratory for certain physicochemical and biological parameters. About 95 questionnaires were also administered at Abume to households to ascertain their concerns with the water from the dam. The results indicated that the operation of AHPP has statistically significant effects on pH, Dissolved Oxygen (DO), faecal coliform and total coliform. The DO and total coliform did not rejuvenate by the 1km tailrace distance of the study. However, pH rejuvenated at a distance of 750 meters. The people also point out that the quality of the river at Abume is not safe for drinking and living organisms. The study concludes that water from the AHPP downstream is a satisfactory source of raw water that can be treated for domestic use. The water can also not support large fish species like tilapia. The study recommends that cage fishing should not take place close to the tailrace. The Volta River Authority and the government should provide potable drinking water to the communities affected by the construction of the dam and new sustainable turbines should be employed to manage the dam.