Assessing Groundwater Potential in the Ziway Lake Watershed Using Geographical Information System, Analytic Hierarchy Process, and Drinking Water Quality Index

Area of Science:

• Hydrology
• Environmental Science
• Geospatial Analysis

Background:

• Ethiopia's rift valley faces water scarcity challenges.
• Understanding groundwater potential is crucial for sustainable water resource management.
• Ziway Lake watershed requires detailed hydrogeological assessment.

Purpose of the Study:

• To delineate groundwater potential zones in the Ziway Lake watershed.
• To integrate groundwater potential with drinking water quality.
• To provide guidance for groundwater exploration and conservation.

Main Methods:

• Geographic Information System (GIS) and Analytical Hierarchy Process (AHP) for multi-criteria decision analysis.
• Soil and Water Assessment Tool (SWAT) model for estimating groundwater recharge.
• Analysis of environmental factors: recharge, lithology, elevation, lineament density, and drainage density.

Main Results:

• Groundwater potential classified into Very low (18.01%), Low (17.62%), Moderate (12.05%), High (28.34%), and Very High (23.98%).
• Over 50% of the watershed exhibits moderate to very high groundwater potential.
• 39.72% of very high and high potential zones show good to excellent drinking water quality.

Conclusions:

• The study successfully identified and mapped groundwater potential zones in the Ziway Lake watershed.
• Integration with water quality highlights areas suitable for both groundwater abstraction and drinking water supply.
• Findings offer a practical framework for sustainable groundwater management applicable to similar regions.