dc.description.abstract |
ABSTRACT
Groundwater becomes a priceless and dependable natural resource for any human
consumption, development, and ecological services. Thus, prognostic methods of
groundwater exploration, and management is crucial for sustainable utilization and
development. Geospatial science techniques are the foremost effective and efficient tool
for detection of groundwater prospective zones. Therefore, the study aims to detect
groundwater potential zones in Gilgel Abay Watershed using GIS and Remote Sensing
techniques. Lithology, geomorphology, drainage density, lineament density, rainfall, soil,
slope and land use/land cover were identified as the determinant parameters for
groundwater potential zone detection. Satellite images and ancillary data has been used
for preparation of thematic layers using ArcGIS 10.3 and ERDAS 2010 Softwares. MultiCriteria
Decision Analysis (MCDA), Analytical Hierarchy Process (AHP) and Weight
overlay analysis methods have been used to detect the groundwater potential zones by
integrating the thematic layers with different inter and intera-weight. The weightage of
thematic layers were estimated based on their characteristic and relationship with
groundwater recharge and retention capacity. Finally, the thematic maps were integrated
through weighted overlay analysis tool to develop groundwater prospect zones. Based on
the results the study area catagorised into three zones, namely high, moderate and low
potential zones with an area of 106.40km
2
(6.42%), 1348.35km
(81.35%) and
202.76km
2
(12.23%), respectively. The prediction was validated through
GWR(Geographically Weighted Regression) with R
2
value of 0.8884 (88.84% accuracy).
The analysis of climate and land use/land cover change shows a negative impact on the
watershed resulting increasing of runoff, and decreasing of baseflow. Moreover, land
use/land cover change has more severe impact than climate change. As a general Gilgel
Abay Watershed shows a symptom of overabstraction, mismanagement, exponetialy
growing demand of groundwater for different purpose, and intense land use/land cover
change. Detecting groundwater potential before the exploitation, integrated management
of land use/land cover change and watershed management through participating all
stakeholders to increase infiltration/enhance recharge and decrease runoff, and
protection of all usable groundwater resources, should be undertaken for effective site
selection, sustainable groundwater development, utilization and management, based on
the assumption that all effectively accessible groundwater resources are, or could be,
tapped for drinking or other purposes now or in the future.
Keywords: Groundwater potential, GIS and Remote Sensing , Gilgel Abay Watershed,
Multi Criteria Decision Analysis(MCDA), Weighted Overlay Analysis
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