River Ground Water and Sediment Quality

The Effects Of Land Use Within Michigan State University’s Watershed On Water Quality In The Red Cedar River

Author : Shawn McElmurry 

Traditionally, the influence of land use on the quality of surface and subsurface water is evaluated through studies of sub-watersheds or sourcesheds at the regional scale. These sourcesheds are typically quite heterogeneous, with wide variability in hydrologic characteristics, in land use activities, in the pollutant loads generated, and in the impacts on water quality. As a result, this approach requires the use of broadly averaged hydrologic and chemical loading parameters. Thus it is difficult to delineate specific cause-and-effect relationships necessary to efficiently achieve specific water quality goals through land-use management strategies. This problem becomes particularly acute in urban and suburban environments because of the very high density and wide diversity of very small-scale land uses (e.g., roads, parking lots, buildings, landscaped zones and natural areas).

The Michigan State University Red Cedar River Project (MSUWater http://www.msu-water.msu.edu/) affords an opportunity to develop an approach for understanding of how specific land uses affect water quality using the MSU campus as a pilot study area. The foundation of our approach is to develop an understanding of water and chemical transport throughout the campus land area using a combination of deterministic and stochastic methods. The hydrology subproject involves delineating microwatersheds, defined by topography and the stormwater collection system, the complex network of storm drains and outfalls, and the physical characteristics of the river. This information will be used to construct predictive mathematical models describing runoff from the microwatersheds, transport to the river through the drainage system, and transport in the river. It will be necessary to calibrate these models using historical rainfall and stream discharge data, parameter estimation techniques from the literature, and field measurements.

The chemistry subproject involves collecting information on land use activities in the microwatersheds and the pollutant loads they are likely to generate. Since water is the vehicle for chemical transport in this system, a description of chemical and biological pollutant transformation processes can be superimposed on the hydrologic models to understand loading to the river and the downstream impacts. Given the complexity of the MSU system, it will be necessary to selectively focus on a limited number of pollutants. The chemical transport models can then be calibrated using a) information from laboratory studies and the literature on mass-transfer and reaction rates, b) field measurements of source concentrations and loading rates, and c) field surveys for critical physical, chemical, and biological parameters. Model verification will be accomplished by comparing model predictions with field measurements of river water quality at several upstream, on-campus, and downstream locations.

The verified model can then be used as a predictive tool to evaluate the impacts of land use management strategies at the microwatershed scale. Results of this study will aid in current and future land use planning issues, locally and regionally; provide a framework for designing watershed management plans, locally and nationally; and assist regulatory agencies to clarify and prioritize monitoring requirements aimed at improving watershed conditions.