Numerical modeling of hydrodynamics and water quality in tropical urban estuaries: A review with emphasis on sanitation and coastal management

Tropical urban estuaries are environments of high ecological, socioeconomic and sanitary relevance, acting as transition zones between continental and marine systems and concentrating multiple water uses, tourism, fisheries, urban occupation, wastewater discharges and sanitation-related pressures. Intensified coastal urbanization, hydrological variability, altered discharge regimes and inputs of organic matter, nutrients, fine sediments, suspended solids and fecal-indicator microorganisms have increased the need for tools capable of representing pollutant transport, dispersion, dilution, retention and transformation. In this context, numerical hydrodynamic and water quality modeling has become a strategic approach for understanding estuarine circulation, coastal plume dynamics, water renewal, ecological responses and the effects of pollution sources on environmental quality. This article reviews literature published between 2022 and 2026 on the application of numerical models to assess hydrodynamics, water quality and pollution in tropical urban estuaries and associated coastal environments. Scopus, ScienceDirect, SciELO and Wiley Online Library were consulted, and 40 studies were selected for the final review matrix. The revised analysis expands the discussion of widely used platforms, including Delft3D-WAQ, WASP, EFDC, TELEMAC, FVCOM, SCHISM, MOHID, CE-QUAL-ICM/CE-QUAL-W2, SLIM and MIKE-Eco Lab, and compares their strengths and limitations for estuarine applications. The review highlights that practical reliability is constrained mainly by limited field data for calibration and validation, especially for biogeochemical, microbiological and sediment-related variables. The findings show that modeling is most useful when hydrodynamics, pollutant fate, fine-sediment dynamics, ecological indicators and sanitation scenarios are integrated into monitoring and decision-support frameworks.