Enhancing Denitrification in Rural Streams:Washington County Joshua Cockroft Johanna Nifosi Robert Johnson Geldar Matungwa Louise Yazzie

Washington County has Agriculture, Forest and Urban Land Use

Washington County is Largely Agriculture County Ordinance Agriculture accounts for 114,065 acres in 2007 Located in the Upper Potomac

Nitrogen Content is Directly Related to Agriculture Nitrogen Loads and Concentration Land Use Only Nitrogen Loads and Concentration with Land Use

Types of Permits for N mitigation measures General permits Individual permits

Federal and State Agency Roles on Wetland Permits US. Army Corp of Engineers US. Environmental Protection Agency National Marine Fisheries Service Maryland Department of the Environment Maryland Department of Natural Resources

Three Creeks with High Levels of Nitrogen Load and Concentration Meadow Brook Troupe Run Little Conocheague Creek

Legume Cover Crops Reduce N Fertilizer Use Cover CropN replacement values (kg/hectare) Hairy vetch80-89 Hairy vetch170 Winter legume64-69 Hairy vetch110 Crimson clover88 Winter legume75

Additional Benefits of Cover Crops Herbicide reduction Reduction in insect and nematode control costs Protection of ground water Increased water infiltration Increased soil health.

Maryland Government Supports Water Quality Programs in Washington County The Maryland Agricultural Water Quality Cost-Share program (1984) provides grants. $257,648 given to the winter cover crop program in Washington County. 5,786 acres of the county planted cover crops in

Cover Crops Significantly Reduce Nitrogen Load Majority of crops in Washington County in 2007 were Corn and Wheat In studies, corn/wheat combo found 76% reduction Significant potential decrease in nitrogen loads, but not below 10,000 kg/m 3 *yr

Floating Wetlands denitrifies

Contain nutrient consuming wetland plants, they host a nitrifying and denitrifying bacteria on their roots that grow down through the water column. 47% nitrogen removal in agro lands. Low cost Need between 9-13 mats in 1 creek Troupe Run Little Conococheage Meadow Brook Width Nitrogen Load Removal 1st mat Removal 2st mat Removal 3st mat Removal 4st mat Total Mats Required to Reduce to <10,000 kg/yr Floating Wetlands also significantly decrease nitrogen loads

Pros/Cons of Cover Crops Pros – Cover crop program already in place – Increased benefits for farmers – Privately run and operated Cons – Not as efficient – Costs for Farmers to plant – Cover crop program appears to have had not had significant reduction in loads since inception

Pros/Cons of Floating Wetlands Pros – Low Cost – More Efficient – Not on farmland Cons – Regulation Permits – Program not in place

References Maryland Department of Agriculture Providing grants to help farmers. Accessed from 07.pdf 07.pdf Maryland Agricultural Water Quality Cost-Sharing program Annual report. Accessed on Nov 6, 2010 from Washington County Government Accessed on Nov from md.net/washco.shtmhttp:// md.net/washco.shtm