Geospatial information based on UAV for socio-environmental problems in an urban river

Abstract. This study addresses socio-environmental issues affecting the Pesquería River in the Metropolitan Area of Monterrey (MAM), Nuevo León, Mexico, through the integration of unmanned aerial vehicles (UAVs), photogrammetric analysis, and community participation. The river faces critical challenges such as clandestine dumping, illegal wastewater discharges, irregular settlements, and solid waste accumulation, conditions exacerbated by rapid urbanization and weak environmental enforcement. High-resolution RGB and LiDAR imagery was acquired using UAVs, enabling the generation of orthophotos and dense point clouds through Structure from Motion (SfM) techniques. Ground control points (GCPs) ensured spatial accuracy. The methodological approach included citizen engagement through workshops and real-time surveys, which allowed residents to identify and validate environmental problems directly from UAV imagery. This participatory model strengthened community involvement in environmental monitoring. The findings highlight the effectiveness of combining geospatial technologies with local knowledge to document, analyze, and address urban river degradation. This study contributes to a replicable, low-cost framework for socio-environmental diagnostics in complex urban contexts.