Future Gazing for the Eastern Shore

From herons to homes — the Delmarva Peninsula has experienced
profound change over the past twenty-five years.
Photo by Skip Brown

The Chesapeake’s Eastern Shore has been spared from intense development because of its “watery isolation.” At least that’s what a New York Times reporter wrote in 1982.

A lot can happen in twenty-five years.

Bigger roads and faster highways have made isolation a thing of the past for the Shore, also called the Delmarva Peninsula because it spans the states of Delaware, Maryland, and Virginia. Every day thousands of people cross the Chesapeake Bay Bridge to reach what is now one of the fastest growing regions in the Chesapeake watershed. It’s not unusual to see clusters of homes on farm fields, big-box stores where pine forests once stood. Increasingly, the Eastern Shore is considered not only a get-away destination, but a permanent home. And nearly all indications point to further growth in the future.

Without proper planning, development threatens to damage one of the Shore’s most important assets, its waterways. What will more development mean for the health of the area’s streams, creeks, and rivers?

A team of researchers, funded by Maryland Sea Grant, is working to help managers predict what different patterns of development might bring. Their goal is to create a free, web-enabled program that will allow local governments to forecast how future growth could impact hydrology on the Delmarva Peninsula.

Glenn Moglen, a surface water hydrologist and geographic information system (GIS) expert, leads the effort. Moglen, who holds a joint appointment with the University of Maryland’s Department of Civil and Environmental Engineering and the National Center for Smart Growth Research and Education, says the team will complete the project in three distinct steps.

Land-use planner Jim Riley will provide the foundation for the work — numerical forecasts of regional growth. Formerly with Maryland Department of Planning and now an independent consultant, Riley specializes in a computer model called GAMe. With this model he’ll produce growth and land-use forecasts based on certain metrics — things like proposed highway improvements, immigration estimates, housing trends, and environmental drivers such as sea level rise.

Claire Jantz, a land-use change modeler and professor at Shippensburg University will then use the numbers produced by GAMe to make digital maps (GIS maps) showing where growth is likely to occur.

Their work comes together with Moglen who will carry out the final step in the analysis. Moglen will take Jantz’s maps and embed them into GISHydro, a computer program he developed to create and evaluate hydrologic models for watershed analysis. “It’s a natural marriage,” he says.

Smatterings of color illustrate Maryland’s current land-use patterns
in a screenshot of the GISHydro computer program. The version
under development will allow managers to select future land-use
projections and predict their effect on the Shore's waterways.

GISHydro has been used in Maryland since the mid-1980s. Up until now, Moglen notes, 80-90 percent of its audience has used it almost exclusively to predict floods based on current land use. But by coupling it with GIS maps that illustrate various future land-use scenarios, the scope of GISHydro’s use should broaden dramatically. The improved tool will show local planners how various development scenarios could evolve in their town. It will detail impacts on water quality, hydrology, and in turn, biodiversity.

The value of this approach, says Moglen, is that managers on the Eastern Shore who are trying to envision the future, can compare alternate scenarios. They can ask, “What does it mean for where I am, what does it mean for flood behavior, or for water quality?”

Moglen hopes that the tool will not only give managers a look into the future, but also help them to shape it. Ultimately, he notes, this will allow land-use planners to decide among various land-use options. This should give them the chance to make choices that mitigate adverse impacts on the streams and rivers flowing into the Chesapeake Bay.

These land-use decisions could have important legal ramifications as well. The federal Clean Water Act calls for limits in the amount of pollutants in impaired waters. Future development patterns could play a role in adhering to these limits, termed total maximum daily loads (TMDLs).

Jim George, manager of the Water Quality Protection and Restoration Program at Maryland Department of the Environment, also currently funds refinements of GISHydro to support his work on managing nonpoint source pollution loads in Maryland’s waterways. He notes that the new incarnation of GISHydro could “become a valuable tool” for managers. “I’m happy to see Maryland Sea Grant’s support,” he says.

Research and development like this is key, George says, for the growing field of predicting and mitigating ecological impacts of future development, especially in the context of implementing TMDLs.

With over 700 Maryland waterways already listed as impaired, the field is emerging at a critical time. Without informed land-use planning, where will we be twenty-five years from now?

-- Jessica Smits