Detection of Potential Groundwater Zones through Synthetic Aperture Radar Imagery Processing in Sucre (Bolivia)

Abstract

The scarcity of drinking water in urban areas of semi-arid regions requires fast, cost-effective, and replicable groundwater prospecting methods. This study integrated Sentinel-1 Synthetic Aperture Radar (SAR) imagery processed in Google Earth Engine (GEE) with vertical electrical sounding (VES) to identify areas with hydrogeological potential in District 3 of Sucre, Bolivia. A GEE script was developed to calculate the change index (VH-VV) over a time series of images, generating a threshold mask to detect surface moisture anomalies. Validation consisted of a spatial correlation analysis using Pearson correlation coefficients and root mean square error (RMSE), based on 54 wells registered by the Local Drinking Water and Sewerage Company of Sucre (ELAPAS) and 25 VES points, obtaining Pearson coefficients ≥ 0.997 and RMSE values of 30.52 m and 77.59 m, respectively. A total of 25 areas with potential groundwater occurrence were identified, of which 8 were found to be viable for well design. The results demonstrate that the SAR-VES-GEE synergy constitutes a preliminary screening tool for the identification of areas with groundwater potential, aimed at supporting groundwater resource planning in municipalities with limited technical resources.