A one health google earth engine web-GIS application to evaluate and monitor water quality worldwide

The assessment of water quality using satellite remote sensing has gained significant interest in recent years. Earth Observation data and technologies, particularly through cloud-based platforms like Google Earth Engine (GEE), offer the potential for synoptic coverage and repeated monitoring. This study aimed to develop a Google Earth Engine app for indirect monitoring and assessment of water quality based on Sentinel-2 from a One Health perspective. A JavaScript code was written within GEE to develop a publicly accessible application in order to permit users to indirectly analyze water-bodies world-wide in the spatial–temporal domain. In particular, clouds, shadow and defective pixels were masked out in the entire collection using Quality Assurance (QA) masks. Regarding to the application, named Sen2WQ, several functions were implemented in order to compute: water turbidity (T), chlorophyll (Chl) content, and total suspended solids (TSS) based on established approaches in the scientific literature. The application allows users to map water quality (T, Chl, TSS) within their defined time range and area of interest, displaying time-lapse visualizations, maps, and charts. To validate the app, different remote sensing tools and ground data for these parameters were collected in Italy and worldwide, and Root Mean Squared Error (RMSE) was computed. The results demonstrate the potential of GEE, specifically the Sentinel-2 missions, in monitoring water quality. Sen2WQ may support different figures such as veterinarians in studying animal and wildlife pathologies related to water quality, contributing to a comprehensive One Health approach.