Water Source and Water Demand Needs Assessments for Bonwire

Abstract

This work assessed the water supply source and water demand of Bonwire, a town in the Ashanti Region of Ghana. The work was done to solve an identified water threat in Bonwire. The assessment was done via the identification and discharge quantification of water sources; the physicochemical and biological assessments of the source(s); estimation of water needs and a comparison of the supply and demand in Bonwire, and to recommend this assessment to the local government and Donor Agencies. The methodology for the work was site reconnaissance and desk studies, water discharge measurement via area-velocity method, field sampling and laboratory testing. The ions were analysed by ICP-AES and IC. The current water demand was estimated as 274 m³d^-1.The  two sources of water identified for Bonwire were four (4) rivers and groundwater from two (2) boreholes. The discharge measurements and borehole yields indicated that the total discharge for Bonwire is 14,239 m³d^-1 of which rivers contribute about 99%.  Inspite of the large river discharges, the physicochemical properties finger the river waters as unpotable, because the rivers are contaminated with contaminants (nitrates, sulphates, coliform) and hardness. The groundwater source which is the only potable source has a daily discharge of 86 m³d^-1, which is in a deficit of 188 m³d^-1 for the current water demand. It was concluded that there was a water threat in Bonwire. It was therefore recommended that contamination of the rivers should be controlled; a hydrogeological assessment for additional borehole drilling should be conducted, and  the possibility of treating the rivers for supplying water to Bonwire and the Municipality should be considered.

Keywords: Water Supply, Water Demand, Water Threat, Contaminants, Coliform, Water Hardness, Hydrogeological Assessment