Effects of Land Use within the MSU Watershed on the Water Quality of the Red Cedar River
Investigators:	David T. Long, Thomas C. Voice, Phanikumar Mantha

One of the objectives of the MSU WATER (Watershed Action Through Education and Research) project is to develop a framework to quantify the effects of land use on water quality of the Red Cedar river. A key component involves the development of hydrodynamic and transport models for the river itself. During summer 2002, we conducted a series of dye dispersion studies using flourescein as a tracer, measured water velocities, discharges and river stages to better understand hydrodynamics and transport in the river. To predict flow and transport of both conservative and reactive components, we developed models based on USEPA’s DYNHYD and WASP (USEPA) modules. We also developed finite-element models of the river based on two-dimensional, vertically integrated St. Venant equations using SMS, RMA-2 and RMA-4 packages. To understand the role of longitudinal dispersion in a natural stream such as the Red Cedar river, we used a storage zone model in which tracer mass is assumed to reside in the main channel as well as in storage or dead zones along the banks. The model parameters have been estimated using non-linear gradient-based parameter estimation methods. Comparison of the simulated and observed tracer concentrations at three different stations are shown in Figure 2. The tracer transport model forms the first step in developing reactive transport models that include a number of processes such as sorption and degradation. Future studies will integrate the river models with GIS to understand fluxes at the watershed scale. More details can be found at the MSU-WATER project web page.