POTENTIAL GROUNDWATER RECHARGE ZONE MAP IN ISLAND GARDEN CITY OF SAMAL (IGACOS)

Abstract

Groundwater is our major source of water. This study focuses on developing a groundwater recharge zone map using Geographic Information System (GIS) software techniques and Analytical Hierarchy Process (AHP) model. The map incorporates various influencing thematic layers sourced from local government agencies and generated through simulations in ArcGIS software. The thematic layers are Land Use/Land Cover (LULC), Geology, Soil, Slope, Lineament, Drainage, and Rainfall. These thematic layers are validated using existing data and maps from the Island Garden City of Samal-City Planning and Development Office. In generating the recharge zone map, the thematic layers are overlaid using weighted overlay analysis, and the weights are determined using the AHP method, following Saaty's 1980 approach. After generating the groundwater recharge zone map, it is crucial to validate its accuracy and reliability. This validation process involves comparing the map with the locations of existing well and employing key informant interviews. By cross-referencing with existing wells, we can assess the map's alignment with existing groundwater resources. Additionally, key informant interviews provide valuable insights from residents and barangay officials, validating the map practically. This study provides an effective and reliable groundwater recharge zone map by combining GIS software techniques, AHP model, and rigorous validation methods. The groundwater recharge zone map shows the location of groundwater resource level of potentiality that can serve as a valuable tool for water resource management and groundwater source planning in the Island Garden City of Samal (IGACOS).