Monitoring of Water Surface Area Using Optical and SAOCOM SAR Data: A Case Study of the Nihuil Reservoir, Mendoza, Argentina

The present work evaluates the Water Surface Area (WSA) of Nihuil reservoir, located in Mendoza, Argentina employing optical images of different sources (Landsat-8, Landsat-9, Sentinel-2), and Synthetic Aperture Radar (SAR) data of the SAOCOM-1 mission. Thresholding algorithm, morphological operations and segmentation techniques were applied to obtain temporal and spatial variability of Nihuil reservoir in 6 years, from 2018 to 2023. Validation was carried out using WSA provided by DGI (General Irrigation Department of Mendoza province). Final results show a <tex>${R}^{2}=0.97$</tex> and RMSE = 273.18 ha between all satellite estimated values and validation data. The proposed methodology facilitates the acquisition of WSA products without the requirements for field or auxiliary data, thereby enhancing the effectiveness of hydrological monitoring.