摘要
Sustainable development and management of groundwater resources require application of scientific principles and modern techniques. An integrated approach is implemented using remote sensing and geographic information system (GIS)-based multi-criteria evaluation to identify promising areas for groundwater exploration in Raya Valley, northern Ethiopia. The thematic layers considered are lithology, lineament density, geomorphology, slope, drainage density, rainfall and land use/cover. The corresponding normalized rates for the classes in a layer and weights for thematic layers are computed using Saaty’s analytical hierarchy process. Based on the computed rates and weights, aggregating the thematic maps is done using a weighted linear combination method to obtain a groundwater potential (GP) map. The GP map is verified by overlay analysis with observed borehole yield data. Map-removal and single-parameter sensitivity analyses are used to examine the effects of removing any of the thematic layers on the GP map and to compute effective weights, respectively. About 770?km2 (28?% of the study area) is designated as ‘very good-GP. ‘Good- ‘moderate-and ‘poor-GP areas cover 630?km2 (23?%), 600?km2 (22?%) and 690?km2 (25?%), respectively; the area with ‘very poor-GP covers 55?km2 (2?%). Verification of the GP map against observed borehole yield data shows 74?% agreement, which is fairly satisfactory. The sensitivity analyses reveal the GP map is most sensitive to lithology with a mean variation index of 6.5?%, and lithology is the most effective thematic layer in GP mapping with mean effective weight of 52?%.