The Influence of Land-Use on Water Quality in a Tropical Coastal Area: Case Study of the Keta Lagoon Complex, Ghana, West Africa

Abstract

The Keta Lagoon and its catchment areas in Ghana are influenced by intensive agriculture and the use of agro-chemicals. It has therefore, become necessary to assess the quality of water in the lagoon and the surrounding fresh water aquifers. In this study, a water quality index (WQI), indicating the water quality has been adopted. The WQI was determined on a basis of various physico-chemical parameters like pH, conductivity, turbidity, dissolved oxygen, calcium, magnesium, chloride, nitrates, ammonium and sodium. The index was used both for tracking changes at one site over time, and for comparisons among sites. The WQI was also employed to wells used for irrigation on farms along the Keta Sand Spit as well as that of the Keta Lagoon Complex and its surrounding floodplains, in order to ascertain the quality of water for public and livestock consumption, irrigation, recreation and other purposes. The WQI of the wells, Keta lagoon and its floodplains showed various degrees of poor water quality and therefore considered unsuitable for drinking and recreation. By WHO standards, this calls for intensive physical and chemical treatment of the water for human consumption.