Local development of affordable lime in southern Africa: Project Summary Report

[摘要] Three groundwater maps have been created for the Oju/Obi area of Benue State, Eastern Nigeria. These maps are at 1 : 100 000 scale and have been developed using a Geographical Information System (GIS). Information on the maps is generally accurate to about 200 m, although the geological boundaries marked on the maps are taken from data sources which are much more approximate. The following information is given on the maps: Groundwater Development Map: geological units, rivers, roads, aeromagnetic anomalies, location and identification number of villages, limits of information confidence, areas of similar groundwater chemistry, conductivity of groundwater samples, location of BGS exploration boreholes and an explanation of the groundwater potential of the various rock units. Hydrogeology Map: geological units, rivers, roads, aeromagnetic anomalies, villages, lineations interpreted from satellite imagery, surface water catchment boundaries, location and identification number of BGS exploration boreholes, locationo of BERWASSA and pre-97 boreholes, raingauges, water-level monitoring points, graphs of monthly rainfall for 1997 and groundwater-level fluctuations for 1997. Aerial photography interpretation: outline of geological units, aeromagnetic anomalies, roads, lineations interpreted from satellite imagery, lineations interpreted from aerial photographs, dambos interpreted from aerial photographs. The maps are based on a variety of data sources including satellite imagery, aerial photographs, published geology, aeromagnetic and topographic maps. Boreholes and villages have been located using a handheld GPS. Preliminary results from exploratory drilling and testing by BGS have been incorporated into the maps. As more data are collected, these maps and in particular the hydrogeological descriptions of the geological units will change. The maps are designed to help plan water supply projects within Oju and Obi and should be used in conjunction with field studies and geophysics to site wells or boreholes.

[发布机构] British Geological Survey

[学科分类] 地球科学(综合)