Using Geospatial Techniques and Analytic Hierarchy Process to Map Groundwater Potential Zones

Area of Science:

• Hydrology
• Water Resource Management
• Geospatial Analysis

Background:

• South Africa's Luvuvhu River Catchment (LRC) faces surface water scarcity due to extensive agricultural irrigation.
• Declining surface water yields struggle to meet domestic and industrial demands in the upper catchment.

Purpose of the Study:

• To delineate groundwater potential zones (GWPZ) within the LRC.
• To establish alternative water resources and alleviate pressure on stressed surface water systems.

Main Methods:

• Utilized various datasets to extract groundwater controlling factors.
• Employed the Analytic Hierarchy Process (AHP) for factor weighting and weighted sum analysis for GWPZ map generation.
• Validated the GWPZ map using Rainfall Infiltration Breakthrough (RIB) and Area Under Curve (AUC).

Main Results:

• The GWPZ map indicates very high groundwater potential in the lower catchment (409 km²).
• Approximately 50% of the LRC falls within high groundwater potential zones.
• Groundwater recharge estimates varied (8.3% to 16.2%), correlating well with delineated potential zones.

Conclusions:

• The study successfully delineated groundwater potential zones, confirming the viability of groundwater as an alternative resource.
• The GWPZ map provides a crucial tool for sustainable water resource management in the LRC.
• Model validation (AUC 70.9%) confirms the reliability of the groundwater potential assessment.