Assessing nutrient inputs and their impact in catchments, UK

Nutrient concentrations determine the extent to which water bodies are eutrophic. This paper describes an export model, which has been developed for the Environment Agency by Reading University, that predicts total nitrogen and total phosphorus loads from land use, stock headage and human populations. The model has been tested on 32 catchments in England and Wales and can been used to assess the effects of future land use changes and to establish baseline water quality against which change can be monitored. One of these catchments is the Broads, a wetland of international importance. In this catchment the model has confirmed the validity of phosphorus water quality targets and has highlighted potentially significant sources of phosphorus from rural populations and from the use of organic manures.