3. Hydrology of the major water sources of Lake Bosomtwe in Ghana

Abstract

The paper seeks to identify the major inflows of Lake Bosomtwe, the meteoritic lake sited in the Ashanti Region of Ghana. It seeks to establish major annual flows as against the lake evaporation in an attempt to establish the water balance of the lake with a view to understanding the factors that are critical to the sustainability of the lake. The average annual rainfall observed in the catchment was estimated to be 350 mm. This is far lower than the average long-term rainfall recorded in the area, of 1,565.9 mm for the period 1950-1971 or that of 1,263.4 mm for the period 1971 to 1991. Even though there appears to be a decline in the two periods, indicating reduction in rainfall amounts with time, the recorded rainfall is not representative. Based on the recorded rainfall and stream flow data, an estimated annual inflow of 0.14027 km3 was derived, with the major inflows being direct rainfall onto the lake surface (99.81%), Nana Abrewa stream (0.15%), Abono bɔ stream (0.04%) and Atafram stream (0.00% insignificant). In view of the reduced flows as a result of lower rainfalls, it is prudent to both conserve and adapt measures to ensure the lake is sustainably managed.