Os estudos morfométricos auxiliam no planejamento e gerenciamento de microbacias hidrográficas, determinando os parâmetros fisiográficos, de relevo e drenagem para avaliar o comportamento hidrológico da bacia. O presente estudo teve por objetivo caracterizar a morfometria da microbacia hidrográfica do Açude Grande de Caraúbas/RN. Foram utilizados para a delimitação automática da bacia o Modelo Digital de Elevação (MDE), a partir do projeto TOPODATA, obtido junto ao Instituto de Pesquisas Espaciais (INPE) e utilizado o SIG gratuito e de linguagem aberta QGIS, com auxílio dos plugins do GRASS e do SAGA, possibilitando a determinação de parâmetros que remetem a drenagem, forma e relevo. A microbacia possui uma área de 9,706 km2, perímetro de 20,673 km. De acordo com os índices morfométricos é considerada de 4ª ordem, bastante ramificada, de formato pouco alongado, apresenta pequena tendência a grandes enchentes, o relevo correspondeu de plano a suave ondulado. Com isso, a partir do emprego de ferramentas geotecnológicas contribuindo para o zoneamento ambiental de uma área e podendo cooperar para o gerenciamento dos recursos hídricos, bem como para uso e ocupação do solo de forma sustentável.Palavras-chave: diagnóstico, geotecnologias, sensoriamento remoto. Morphometric characterization of the Açude Grande hydrographic microbasin in the semiarid region of Rio Grande do Norte A B S T R A C TMorphometric studies assist in the planning and management of micro watersheds, determining the physical, relief and drainage parameters to assess the hydrological behavior of the basin. The present study aimed to characterize the morphometry of the micro watershed of Açude Grande, Caraúbas/RN. The Digital Elevation Model (DEM) was used to automatically delimit the basin, from the TOPODATA project, from the Space Research Institute (SRI) and use the free GIS and the open language QGIS, with the aid of the SAGA plugin. A micro watershed has an area of 9.706 km2, with a perimeter of 20.673 km. According to the morphometric indices, it is considered to be of 4th order, quite branched, of little elongated shape, with small tendencies to large fillings, or the relief corresponds to a smooth wavy plane. With this, using geotechnological tools to contribute to the environmental zoning of an area and can cooperate for the management of water resources, as well as for the use and occupation of sustainable soil.Keywords: Environmental diagnosis; Geotechnologies; Morphometry.

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.