Evaluation of groundwater resources potential in the Ejisu-Juaben district of Ghana

The increasing stress on freshwater resources due to ever-rising demands and profligate uses as well as growing population of Ejisu-Juaben District is an issue of great concern. The purpose of this study is to make a quantitative estimate of the available groundwater resources in the Ejisu-Juaben district for efficient utilization and management of groundwater resources. The methodology involved the collection and analysis of existing well data and chloride mass balance. The results indicate that the aquifers are composite and composed of weathered regolith of low permeability and high storage and overlying fissured bedrock of high permeability and low storage. Semi unconfined aquifers prevail in major portions, which constitute the principal source of groundwater. The depths of boreholes in the District range from 17 - 75 m with an average of 51 m. Generally Ejisu-Juaben district has low groundwater potential with mean yield, transmissivity and specific yield values of 2.8 m3/h, 12.5 m2/d and 0.95 m3/h/m respectively. Recharge in the district is estimated as 7 - 9% of the average annual rainfall of 1874 mm. The permanent water reserve of 326,064,375 m3 and recoverable water reserve of 130,425,750 m3 for the aquifer of the basement complex aquifer were estimated from the records of 97 boreholes

Reconnaissance Survey of Arsenic Concentration in Ground-water in South-eastern Ghana

Arsenic (As) analysis of 150 boreholes in the south-eastern part of Ghana (Accra, Eastern and Volta regions) revealed low to medium concentrations in the range of 2-39 mg l-1, with only 2% of boreholes tested having arsenic concentration exceeding 10 mg l-1 of the WHO (2004) maximum permissible level of arsenic in drinking water. The measurements were carried out in the field using the Wagtech Arsenator field test kit (Wag-We 100500) equipment, which gives direct readout of arsenic concentration in the critical range 2-100 mg l-1. Arsenic concentrations were in the range < 2–39 mg l-1 with mean (< 2 mg l-1) and median (< 2 mg l-1). Out of 150 samples analysed, 147 had As concentration below 10 mg l-1. Three boreholes in the Recent Sand Formation in southern Volta Region at Atitekpo, Mafi Devime and Woe Aklorbordzi had arsenic concentrations of 28 mg l-1, 19 mg l-1 and 39 mg l-1, respectively. Though the sample of boreholes tested was only approximately 10% of the total number of boreholes in the study, the distribution within the sample makes the generalization that the risk of arsenic contamination of rural water supply in southeastern Ghana is generally low plausible. In spite of this assertion, boreholes in the Recent Sandy Formation have to be critically assessed to determine the extent of arsenic contamination and, if possible, monitored.West African Journal of Applied Ecology Vol. 13 2008: pp. 16-2