Modelling the impact of river flow, macronutrients and solar radiation on the eutrophication status of small shallow estuaries

Small, semi-enclosed basins have often been the location of human settlements; however, this has subjected them to extensive anthropogenic use, negatively impacting water quality and increasing their susceptibility eutrophication. A coupled depth-averaged hydrodynamic-biogeochemical model configured shallow, microtidal Christchurch Harbour estuary, Dorset UK, investigate processes driving declines in ecosystem health with particular emphasis on understanding impact changing river flows, nutrient inputs solar radiation. Instances summer oxygen undersaturation increased levels chlorophyll were found coincide regions within estuary yielding long residence times, even under low conditions. Inverse relationships between time undersaturated both flow concentration observed but no significant correlation irradiance which we attribute estuary's shallow nature. Our results showed that although controls estuarine renewal, plays greatest role eutrophication development small, basins.