To help resource managers improve the health of coastal waters degraded by nutrient pollution, a group of scientists has developed a framework for prioritizing stream restoration efforts aimed at reducing the amount of nitrogen flowing downstream. The framework, published in the online version of the journal Frontiers in Ecology and the Environment, will allow practitioners to make better informed decisions regarding the design and implementation of restoration projects, which is critical for decreasing the downstream movement of nitrogen.
"Unlike previous research focusing on removing nitrogen before it reaches streams, we are investigating innovative ways to reduce excess nutrients while the water is flowing to its ultimate destination," said Dr. Margaret Palmer of the University of Maryland Center for Environmental Science. "By combining this type of restoration technique with more traditional measures - like streamside forest buffers - we should be able to help nature help us by using some of the excess nitrogen before it flows downstream."
Stream restoration has become increasingly popular across the country, yet efforts to quantify the actual amount of nitrogen removed by these costly projects are only just beginning. By providing natural resource managers with advice for prioritizing and designing projects aimed at reducing the downstream flux of nitrogen, the researchers hope to help local, state and federal restoration officials make larger nutrient pollution reductions with the limited amount of available funds.
The framework is based on identifying areas where large amounts of nitrogen loads are delivered to local streams and are then transported downstream without being used by the local ecosystem. Small streams (1st-3rd order) with considerable nitrogen loads delivered during low to moderate flows offer the greatest opportunities for nitrogen removal. The authors suggest restoration approaches that increase in-stream carbon availability, contact between the water and stream sediments, and connections between streams and adjacent terrestrial environments will be the most effective. There is strong scientific evidence that restoration projects are more likely to be successful when properly designed using such a framework.
This research which was led by Palmer and her graduate student, Laura Craig, was supported by the Maryland Power Plant Restoration Program and Versar, Inc. and the US EPA's National Center for Environmental Research. The article, "Stream restoration strategies for reducing river nitrogen loads," represents the consensus views of leading stream researchers from eight U.S.-based institutions.
The University of Maryland Center for Environmental Science is the principal research institution for advanced environmental research and graduate studies within the University System of Maryland. UMCES researchers are helping improve our scientific understanding of Maryland, the region and the world through its three laboratories, Chesapeake Biological Laboratory in Solomons, Appalachian Laboratory in Frostburg, and Horn Point Laboratory in Cambridge, as well as the Maryland Sea Grant College.