Gis and Remote Sensing Integrated Environmental Impact Assessment Of Irrigation Project In Finchaa Valley Area
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Date
2006-07
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Addis Ababa Universty
Abstract
This research was conducted in order to assess the environmental impacts of Finchaa
irrigation project using GIS and remote sensing techniques. Because of the limited
resources only some environmental parameters were selected. These parameters are
natural vegetation, soil/land, water quality, climate and health conditions.
The normalized vegetation index (NDVI) analysis was used to detect the spatial and
temporal change of vegetation biomass in the study area. The result indicated that the
natural vegetation biomass is declining. This is mainly due to the expansion of
agricultural land and escalating human made structures in the area.
The water physico-chemical analysis demonstrated that the down stream water has more
chemical substances and degraded physical properties than the up stream counterparts.
The direct leakage of industrial liquid waste and the agro-chemicals from irrigation fields
are supposed to contribute for this result. The GIS analysis of a 100 meter buffer around
Major rivers and tributary streams is found to be a necessary action to mitigate the
problem of pollution.
The soil chemical and physical property analysis in the irrigated and non irrigated fields
reveals that the soil samples taken from irrigated fields contain higher phosphorous,
Nitrogen and organic carbon compared to its counter parts. The use of agro-chemicals in
the irrigation fields contribute for the result.
From the twenty two years rain fall, temperature and humidity data no abrupt inclining or
declining trend is observed that could tell the possible impacts of the project.
The post irrigation development years witness that some water born diseases and malaria
case records have increased. It is also found out that expansion of irrigation fields and the
respective Malaria case records are positively correlated.
Generally, despite the significance of the Finchaa irrigation project, it has negative
environmental repercussions. This is evident from vegetation cover distraction, water
quality deterioration in the down stream area, alteration of soil physical and chemical
components and increasing health threats. If the current condition continues the problems
may out weight the benefits of the irrigation project. Thus in the project site and
adjoining areas urgent environmental conservation is necessary. This helps to sustain the
existing and revitalize the fading resources
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Keywords
Gis and Remote Sensing