Although software already exists for estimating nitrogen loading in rivers and lagoons, it is typically limited to basins a few kilometres wide, because of the amount of input information needed to process the calculations. The new model, developed by Sylvain Payraudeau at the French Institute for Agriculture and the Environment, Cemagref, requires only a few pieces of information to estimate loading across basins 50 km wide. It can also predict the effect of rain on the movement of nitrogen.
The model is designed to help France estimate the build-up of nitrogen in Mediterranean basins polluted by sewage plants and agricultural run-off. Areas such as the Herault lagoons are typically subject to flash floods followed by long periods of drought, and regularly suffer from eutrophication.