Understanding crop water use is essential for improving agricultural water management and ensuring sustainable food production, especially in regions with limited water resources. Evapotranspiration (ET) is a key component of the hydrological cycle, directly influencing irrigation planning and crop productivity. However, accurately estimating ET at local scales remains a challenge due to the limitations of conventional measurement methods and the difficulty of integrating high-resolution remote sensing data. This study investigates the estimation of terrestrial evapotranspiration (ET) in a sugarcane cultivation area located in the northern coastal region of Paraíba, Brazil, using meteorological data and aerial images acquired by an Unmanned Aerial Vehicle (UAV). We adapted the PT-JPL model to estimate ET at the local scale, using thermal and multispectral imagery obtained from UAVs. Data validation was performed using surface energy balance measurements obtained from a micrometeorological tower, thereby enabling comparison of estimated and observed ET values. The results demonstrated strong correlations between modeled predictions and field measurements of net radiation (R² = 0.85), with performance metrics indicating moderate reliability for local-scale simulated ET when compared to flux-tower-based ET (R² = 0.48; RMSE ≈ 0.045 mm/30 min). This research highlights the potential of integrating UAV-based remote sensing with the PT-JPL model to improve understanding of crop water use, support irrigation management, and contribute to sustainable agricultural practices.

This study aims to present how continuous and systematic monitoring in representative and experimental watersheds can help form high-level professionals and researchers in water resources, based on a case study of the Onça Creek Watershed (OCW). Through a historical survey of the monitoring network and the scientific studies carried out in the area, we identified people and map their geographical and professional location, to analyze the impact and importance of this area for the water resources community. We identified 90 scientific studies already developed at the OCW, which resulted in 22 masters and 4 Ph.D. students formed, involving another 33 external collaborators. We observed that 85% of the trained professionals continue to exercise functions related to water resources, in public and private institutions, throughout Brazil and abroad. We highlight the importance of financial support from research and development agencies, both for the monitoring network expansion and the training students' scholarships. We believe that the involvement of water resources graduate programs can be a way to increase the number of experimental and representative watersheds monitored in Brazil.