The hypoxic zone in the Gulf of Mexico is a symptom of a greater problem of nutrient loss to streams across the American Midwest. The United States Environmental Protection Agency (EPA) has responded to the problem by requiring states along the Mississippi River to develop nutrient reduction strategies and implement practices that reduce nutrient loss. The state of Iowa developed their strategy and formed the Iowa Nutrient Research Center (INRC) to study the most effective conservation practices and policies. This thesis is conducted as part of the INRC and is focused on the development of a hydrologic and water quality model of the Cedar Creek watershed in southeastern Iowa.
The Cedar Creek hydrologic and water quality model was created using MIKE SHE, a coupled surface/subsurface modeling software. The model was calibrated using real-time streamflow and water quality measurements taken within the watershed. Several water quality scenarios were tested in order to determine the most effective ways to simulate nitrate concentration within the MIKE SHE framework. The results of this thesis will guide future hydrologic and water quality modeling in agricultural watersheds and serve as a demonstration of the ways to simulate nutrient transport within the landscape.