Ground Water Potential Evaluation Based On Integrated GIS and Remote Sensing Techniques, In Bilate River Catchment: South Rift Valley of Ethiopia

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Background

In the present study, an attempt had been made to delineate and classify possible groundwater potential zones in the Bilate River catchment using integrated remote sensing and GIS techniques.
The study area is part of the main Ethiopian rift, it is highly affected by the uplift and subsequent rifting phenomena that created localized and regional fractures and faults of volcanic rocks;
Moreover, the complex spatial and temporal distribution of the volcanic rocks, their different intricate stratigraphic and structural relationships, wide compositional variability, different degree of weathering and topographic position complicate the hydrogeological behavior of the volcanic aquifers and the hydrochemical signature requires systematic and scientific approach of investigation to determine the groundwater potential in the area.

To evaluate and delineate ground water potential zones in the Bilate River catchment using integrated geographic Information system (GIS) and Remote sensing techniques.
To evaluate the ability of currently used GIS and remote sensing techniques to distinguish or delineate target features controlling groundwater occurrence.
To produce hydrogeological map of the area based on the available data interpretation and analysis that will be a good basis for detailed groundwater exploitation work.
To identify the degree of role of groundwater occurrence and distribution controlling parameters in the study area and their relationship to each other.

The study was carried out in several stages to delineate potential groundwater zones as described in the following steps.

The occurrence and movement of ground water controlling factors generated primarily from satellite imageries and existing data
The collected relevant data, in the initial stage of GIS spatial database development various analogue maps were converted into digital format

The generated, collected and digitized data was organized into logical groups of entities
Then, individual entities assigned and converted to characteristic spatial representation format
After making decision on the research geodata base, the data sets prepared
In order to demarcated the groundwater potential zones of study area different thematic maps prepared
Groundwater potential zone map prepared using overlay analysis using IDRIS and ArcGIS software’s.

In this stage, digital image processing of the satellite data carried out for extraction of pertinent information
The different polygons in the thematic layers labeled separately and then they were converted to raster and registered
Prior to integration of different information, individual class weights and map scores was assessed based on Satty’s Analytic Hierarchy process