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