Multiple Models for Watershed Management and Land Use Planning in Coastal Communities

Queenstown & Queen Anne’s County, Maryland

Along Chesapeake Bay, development pressure continues to increase and land use planners must manage growth in a way that improves and protects water quality in the Bay and its watershed. To do this effectively, they need information on how human activity effects water quality, and the ability to predict the outcomes of proposed development and different management approaches. They also need to know which natural features, such as streams, may require a specific management action in order to protect water quality.

Watershed modeling can be one of the best tools to generate this information. However, many models focus on land parcels that are relatively large compared to the scale of management decisions, and, since environmental processes operate on different spatial and temporal scales, no one model can be absolutely accurate. This makes it difficult to communicate the usefulness of a single model’s predictions to land use managers and the public.

With a grant from CICEET, a team from the Smithsonian Environmental Research Center is demonstrating an approach to reduce the uncertainty associated with using a single model. The researchers are developing comprehensive planning tools that objectively evaluate different development scenarios through a two-pronged approach: using multi-model averaging to addresses the uncertainties in predictions and “source prioritization” to help municipal planners interpret model predictions.

In cases where the models’ predictions are in agreement, decision makers can have confidence in the result. Predictions that do not agree will point out areas that need further exploration. The goal is to give planners a powerful tool for comprehensive planning and the development of Federally mandated Total Maximum Daily Load (TMDL) clean up plans.

To evaluate the approach at the municipal and county levels, researchers are partnering with the coastal community of Queenstown and Queen Anne’s County, Maryland. They are also working with the Chester River Association, a volunteer organization that promotes stewardship of the Chester River. Maps and summary tables, as well as information about model and scenario development, will be made available to planners and the general public in other communities in the Chesapeake Bay watershed through a partnership with the Chesapeake Research Consortium and the Chesapeake Community Modeling Program.