1. Wetlands and bioretention systems: Landscape filters in the Bay watershed Andrew H. Baldwin baldwin@umd.edu Department of Environmental Science and Technology

2. 2 Brackish marsh Red maple/skunk cabbage swamp Pickerelweed Saltmarsh mallow

3. M. Perry G. Kearns A. Young R. Aguilar White-footed mouse Bald eagle Blue crab Green sunfish Fishing spider

4. 4 SOUTH RIVER ANNAPOLIS SEVERN RIVER PATUXEN T RIVER CHES BAY Wetlands lie between dry land and the Bay NWI Wetlands Mapper

5. 5 SOUTH RIVER ANNAPOLIS SEVERN RIVER PATUXEN T RIVER CHES BAY They intercept runoff and groundwater

6. N 2 gas (nitrogen removal) Sediment and phosphorus burial

7. Strategic restoration and creation of wetlands for water quality improvement Mitsch et al. 2001

8. Urban Stormwater Wetland Stormwater wetland at the University of Maryland, College Park. Runoff from the parking lot enters the wetland from the left, flows in a roughly U-shaped counterclockwise pattern, and discharges via a riser a the top center of the wetland. Photo by A.H. Baldwin.

9. ** Surface Flow (SF) Wetland Subsurface Flow (SSF) Wetland Soil substrate over impermeable layer (clay, bentonite, liner) Gravel substrate over impermeable layer ** Constructed wetlands for wastewater treatment (e.g. dairy farm effluent)

10. 10 Bioretention systems To stream To groundwater - Store and slowly release surface runoff to streams or groundwater (reduced flood peaks) - Filter out sediment - Remove sorbed pollutants (e.g. phosphorus and metals) These are not wetlands! PG County Bioretention Manual, 2009

11. Laurel Hospital Ivy Club Apartments King’s Contrivance Greenbelt Plaza

12. Conclusions Wetlands and bioretention systems improve Bay water quality “Kidneys of the landscape” Provide biodiversity, flood storage, and other ecosystem services Thank you! K. Jensen

13. Supplemental slides