Aquatic ecosystem restoration in urbanized basins using geospatial and remote sensing tools

Abstract

The impact of rapid urbanization continues to alter hydrology and degrade water quality in urban basins, eroding the resilience of aquatic ecosystems. This research develops a geospatial workflow that integrates remote sensing and GIS-based assessments to diagnose stressors and focus restoration efforts in urbanized watersheds. From processing various satellite sensors, including Sentinel-2 MSI and Landsat 8/9 OLI, along with Sentinel-1 SAR, the Normalized Difference Water Index (NDWI), Modified NDWI (MNDWI), and turbidity reflectance ratios were computed as key indicators. Water body shrinkage, channel modifications, riparian buffer loss, and loss over a decade were assessed through spatial analysis and temporal change detection. To integrate the restoration suitability index derived from multicriteria decision analysis (MCDA), the ecological, hydrological, and land-use variables were combined. Hydraulic fragmentation and elevated turbidity were disproportionately associated with the lower reaches of the watershed, which lacked riparian vegetation and were devoid of urbanization. Floodplains with hydrological disconnection and riparian vegetation deficit were the highest ranked. These results provide comprehensive guidance for NBS coupled with managed urban stormwater to help restore the water ecosystem functions in developed watersheds.