Spatial Analiysis of the Variation in Groundwater Resource Potential in Relation to Rice Productivity in the Dengkeng Sub-Watershed, Central Java

Oleh :
Mufidah Ronaa Jawahiroh - H0222078 - Fak. Pertanian

The Dengkeng Sub-Watershed is an important rice-producing area in Central Java where agricultural productivity depends on groundwater availability. This study evaluated groundwater storage dynamics during 2015-2024 and examined their relationship with rice productivity using a geospatial approach. A quantitative descriptive approach was adopted, with geospatial analyses performed using Geographic Information Systems (GIS) and Google Earth Engine (GEE). Groundwater recharge potential was mapped using the Analytical Hierarchy Process (AHP), while groundwater storage anomalies were derived from GRACE and GLDAS datasets. Rice productivity was estimated using a linear regression model developed from Sentinel-2 Normalized Difference Vegetation Index (NDVI) and rice productivity data obtained from the Badan Pusat Statistik Indonesia (BPS), and the resulting productivity map was validated through interviews with 500 farmers. The results showed that the watershed was dominated by moderate to high groundwater recharge potential, whereas Groundwater Anomaly (GWa) values were predominantly negative, indicating groundwater depletion, particularly during the 2015-2016 El Nino event. The NDVI-based regression model showed a relatively weak relationship with rice productivity (R² = 0.1432), indicating that NDVI explained only a small proportion of productivity variation. Spatial analysis and field validation demonstrated that rice productivity was influenced not only by groundwater availability but also by irrigation systems, soil fertility, agronomic practices, climate conditions, and pest and disease incidence. These findings highlight the need for integrated groundwater and agricultural management to support sustainable rice production.