R/WS-1a

Impact/Outcome:

This section describes how this project has advanced scientific knowledge and/or made a difference in the lives of coastal residents, communities, and environments. Maryland Sea Grant has reported these details to the National Oceanic and Atmospheric Administration (NOAA), one of our funding sponsors.

SUMMARY: University of Maryland researchers built a novel, detailed map showing streams in a large region of Maryland not recorded on other maps. The new map, which identifies small and buried streams west of the Chesapeake Bay, provides a tool that can help efforts to protect streams from development and to improve water quality in the Chesapeake Bay.

RELEVANCE: Streams, especially small ones, can play an important role in improving water quality, a key goal in the Chesapeake Bay watershed. A healthy stream ecosystem can remove excess nutrients, sediment, and other contaminants from water before it flows into the Bay. However, many streams in Maryland have become filled in and buried by construction and development. Knowing the locations of buried stream channels is relevant to planning projects to unbury and restore them. A detailed map of stream channels is also relevant to protecting not-yet-buried streams from development.

RESPONSE: This project was led by Andrew Elmore of the Appalachian Laboratory of the University of Maryland Center for Environmental Science. He and his colleagues created a computer model predicting where Maryland’s network of streams would be located if all of the state west of the Bay resembled the state’s remaining forests. The map combines information about the known locations of 253 stream headwater zones in upland, forested areas of Maryland. The researchers combined this information with other, statewide data about terrain slope and soil characteristics that can indicate the presence of streams.

The resulting map (http://streammapper.al.umces.edu/) identifies a network of stream channels that is up to 2.5 times more dense than the network shown on maps based on a widely used, nationwide database about surface waters, the National Hydrography Dataset (NHD.) Of the predicted stream locations in Elmore’s model, 84 percent were correct, higher than the NHD’s accuracy rate of 55 percent.

RESULTS: In 2013 Elmore and his colleagues published a description of the model in the journal PLoS One. Officials in several Maryland counties are interested in using the map to help them comply with the new rules called TMDLs (Total Maximum Daily Loads) intended to improve the Bay's water quality. For example, the map could help inform where to plant streamside buffers of trees to help remove nutrients and sediments from runoff. In addition, the Maryland Department of Natural Resources says it may incorporate Elmore’s data into its next update of the maps used to create its GreenPrint tool, a statewide map that identifies lands and watersheds as priorities for conservation because of their high ecological value.