Prediction of phosphorus and nitrogen concentrations in lakes from both internal and external loading rates

A variation of the Vollenweider model for predicting phosphorus and nitrogen concentrations from loading rates has been tested using data collected from a shallow, eutrophic lake where both external and internal loading occurred. The results show that most of the assumptions on which the model is based are met and that observed data agree closely with values of nutrient conKentration predicted by the model. It is suggested that the model could be used to predict the decrease in loading rate required to effect lake restoration. Barton Broad in Norfolk was used for the study.