Submarine outfall relocation and the reduction of microbiological risk in bathing waters

Urbanisation of coastal zones increases sewage loads and microbiological risks in bathing waters. This study evaluates whether relocating a planned submarine outfall can reduce these risks while preserving suitable bathing conditions along the Itaipuaçu coast, Rio de Janeiro, Brazil. A coupled framework integrates three-dimensional hydrodynamics, near-field plume simulations, and a Lagrangian far-field transport model with an E. coli decay formulation driven by solar radiation, temperature, and