Assessing the Impact of Land Use And Land Cover Change on Groundwater Recharge Using Rs and Gis; A Case of Awassa Catchement, Southern Ethiopia

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Date

2007-03

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Addis Ababa Universty

Abstract

Humans have exerted large-scale changes on the terrestrial biosphere, primarily through agriculture; however, the impacts of such changes on the hydrologic regime are poorly understood. The purpose of this study was to show the impacts of LU/LC change (vegetation cover reduction) on the subsurface portion of the hydrologic cycle by changing groundwater recharge. The hypothesis was examined through studies investigating the effects of land use/land cover (LU/LC) changes on groundwater recharge in the lake Awassa watershed. Vegetation cover has been changing negatively from 1973-1986 by 168.7 km2area and from 1986-2000 by 108.1 km2 area, and agricultural area has been changed positively from 1973-1986 by 143 km2 and from 1986-2000 by 100 km2. Similarly 6 km2 built up area of 1973 has grown to 8 km2 and 13 km2 in 1986 and 2000 respectively that aggravate surface runoff by creating compacted surface which hinder infiltration. The trend analysis of the ground water recharge and LU/LC change (especially vegetation cover reduction) showed similar trend. The significant change in ground water recharge is due to land use and land covers change (especially vegetation cover reduction) in the catchment for the last three decades, which bring change in the runoff generation and recharge reduction. It is possible to conclude that the LU/LC change specially the vegetation cover reduction have great influence to the recharge reduction than that of meteorological elements. If condition goes like this there will be a significant ground water scarcity in the near future; and this needs an immediate action to reinstate the normal situation, in this regard it is highly recommended to protect the remaining patchs of vegetations in the area and apply both physical and biological conservation measure to reclaim the degraded areas. Keywords: GIS, Remote sensing, Awassa, land use land cover change, surface runoff, and Ground Water Recharge

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Keywords

GIS, Remote sensing, Awassa, Land use land cover change, Surface runoff, and Ground Water Recharge

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