Parsimonious Model for Assessing Nutrient Impacts on Periphyton-Dominated Streams

Abstract

The following paper illustrates how parsimonious process–based models can be used to assess the impact of nutrients on shallow periphyton-dominated streams. After a brief overview of previous research, a simple model is developed to predict periphyton levels below a point nutrient loading to a uniform geometry, steady-state stream. The model is then used to address two eutrophication management questions. First, it is shown how simple models can be employed for nutrient loading calculations, that is, to determine the nutrient loadings necessary to maintain periphyton below nuisance levels downstream of a point source. Then, it is shown how the model can be used to establish nutrient criteria is illustrated, that is, to directly calculate the required in-stream nutrient concentrations to achieve the same objective.