Kentlands Community Park, Prince George's County, MD Wetland Mitigation & Stormwater Management Retrofit

In order to compensate for wetland impacts associated with the construction of Redskin Stadium, ESA designed a four-acre wetland located within Kentland Community Park in Landover, Maryland consisting of forested, scrub/shrub and emergent wetlands. Prior to beginning design, ESA analyzed soil and hydrological conditions at the proposed location to determine wetland creation potential. These initial studies included soil test borings and soil analyses to determine historic groundwater levels, historic aerial photo analysis to identify historic wetland areas and drainage patterns, and a study of the current contributing watershed with its land use values to determine potential run-off. Following these initial studies, ESA installed groundwater wells, performed a TR20 hydrologic analysis and tracked precipitation at local gauging stations. With this data, ESA was able to model groundwater levels and run-off from the contributing watershed during storm events. The data was then used to appropriately size the wetlands and establish proposed elevations.

The wetlands at Kentland Community Park were designed to be supported by a combination of groundwater and stormwater run-off. Functionally, the wetlands were designed to: provide flood desynchronization to reduce erosive discharges into Beaverdam Creek and to improve water quality by filtering pollutants and reduce thermal loading. In addition to these design considerations, passive and active recreation within the Park and the proximity of adjacent property owners had to be addressed. One major issue was the volume of trash being carried into the park during storm events via a storm drain outfall at the head of the proposed wetland area. Prior to our design and following storm events, stagnant water pockets would remain and trash would be strewn throughout the receiving field, creating a nuisance and an eyesore for adjacent property owners and park visitors. ESA designed a dry, vegetated forebay facility with a trash rack in the head of the created wetland to trap trash, remove suspended solids and eliminate standing water. Another major issue was to preserve active recreation opportunities within the park. ESA designed for a gentle transition between the wetland and upland areas to ensure maximum use of park grounds. ESA also designed the wetlands to enhance the visual experience of pedestrians using the walking trails, which parallel and cross the proposed wetlands. Spadderdock, iris, pickerelweed and soft-stem bulrush are displayed in the deeper portions of the wetland with a backdrop of buttonbush, beggars-ticks, swamp rose, American sycamore, willow oak, and river birch. In addition to their aesthetic appeal, ESA selected these plants because they are endemic to the natural wetlands and wetland buffers of the coastal plain in Prince George's County, MD.

ESA prepared all of contract documents for the project including grading plans, planting plans, construction details, specifications, construction sequencing, and erosion & sediment control plans. ESA also applied for and obtained all of the required Federal, State, and County permits for the project. Finally, ESA performed construction supervision for all phases of the project and is currently monitoring the wetlands for a required five-year period to ensure that they meet performance criteria as established by the Maryland Department of the Environment and the U.S. Army Corps of Engineers.