Author(s): Daisy Koch; Dhrubajyoti Sen; Ashok Kumar Gupta

Linked Author(s): Dhrubajyoti Sen

Keywords: Water quality; Urban wetland; Eutrophication; Hydrodynamic and water quality model

Abstract: Eutrophication is a major threat to the urban wetland Deepor Beel, situated in northeast India, adjacent to the city of Guwahati in the Brahmaputra River valley, northeast India. The influx of water into it from the city having a poor quality, and spatial shrinkage due to urbanization have plagued the wetland, a Ramsar site and a resting place for migratory birds and home to a number of endangered floral and faunal species. The wetland's major source of inflow, the Basistha channel, drains the nearby urban catchments, and this study models the combined urban catchment-inlet channel-wetland system using a coupled 1D-2D hydrodynamic and water quality model using the modelling software, MIKE. This approach bridges the gap in traditional water quality assessment techniques, through its ability of predictive, scenario-based simulations. In this study, two key water quality indicators, dissolved oxygen (DO) and biological oxygen demand (BOD), are taken as representative of water quality indicators and the Trophic State Index (TSI) was taken as an indicator of eutrophication in the wetland. The results establish the significance of dilution and reaeration for maintaining good water quality in a small channel like Basistha, and its impact on the variation of DO and BOD across the spatial extent of Deepor Beel. Areas showing high BOD and low DO are identified as locations having poor water quality, and with a potential for eutrophication observed from the TSI levels. The key findings of this study highlight the usefulness of the modelling approach for identifying potential eutrophication zones in urban wetlands, thereby contributing to its conservation and management. This innovative methodological framework will be proficient for eutrophication studies of urban wetlands, especially in the South and Southeast Asia regions.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.173

Year: 2026