Environmental Impact Monitoring For Gilgel Gibe I Dam Using an Integrated Metheds of Remote Sensing and Geographic Information System (Gis)
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Date
2010-06
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Addis Ababa Universty
Abstract
This research has been conducted in order to assess the environmental impacts of Gilgel Gibe I
hydroelectric Dam since its construction using GIS and Remote Sensing techniques. Because of the
limited time only some environmental parameters were chosen. These parameters are vegetation
cover, land use land cover, health conditions in relation to water born related diseases with particular
emphasis on malaria cases. In addition, the socio-economic aspects were also treated.
In order to detect the spatial and temporal change of vegetation biomass in the study area the
Normalized Difference Vegetation Index (NDVI) analysis was used. As per the NDVI analysis made on
ERDAS Imagine9.2 software the mean statistical values are 86.4325, 81.7561 and 66.5724 for the
year of 1990, 2000 and 2008 respectively. According to the results the natural vegetation biomass has
been declined for the last 18 years. This is mainly due to the expansion of agricultural land and a
dramatic increment of human made structures in the area.
The land use land cover change analysis demonstrated that distribution and pattern of land use land
cover of the study area have been undergone through change. Results from land cover change analysis
shows an increase in agriculture land from 20.01 % in 1990 to 32.45 % in 2008. The increased
agriculture land was mainly at the expense of the natural forest. On the contrary, natural forest
decreased from 59.636 % in 1990 to 31.13 % in 2008.The water body covers 2.667 ha during 2000
and 8.866 ha in 2008.This increment was due to the creation of reservoir behind Gilgel Gibe I Dam.
Rate of land cover change clearly showed the change of the different cover classes over the study
periods.
The post hydropower dam reservoir development witnessed that some water born diseases,
particularly malaria case records have shown an increasing trend. It is also found that the creation of
reservoir have been exacerbated malaria cases incidences in the area.
Generally, despite the significance of the hydroelectric dam project, based on the FGD and selected
representative samples it has been found that the construction of Gilgel Gibe I Dam has an adverse
impact on the socio-economic condition of the nearby community and vegetation cover of the area.
Thus, in the project site and adjoining area urgent environmental conservation and an appropriate
mitigation measures are necessary. This may help to minimize the environmental impact and will also
assus the sustainability of the project
Key words: EIA, EMP, GIS, Remote sensing, NDVI, Land use Land cover
Description
Keywords
EIA, EMP, GIS, Remote sensing, NDVI, Land use Land cover