ABSTRACT
Wetlands are an essential part of nature's stormwater management system. This chapter discusses the design and performance standards used for wetland stormwater treatment systems. Objectives of stormwater management are to provide surface drainage, control floods, control erosion and sedimentation, reduce pollutants in runoff, and provide aesthetic amenities, including open space, recreation, and waterfront property. Pretreatment removes heavy sediment loads and other pollutants such as hydrocarbons that can damage the wetland. Pretreatment also attenuates stormwater volumes and peak discharge rates to maintain the wetland hydro-period and to reduce scour and erosion. Erosion and sediment control practices during construction are essential to prevent sedimentation of the wetland. Though little information is available, maintenance is important because accumulation of organic matter and sediment can alter the pollutant removal effectiveness of the system by decreasing storage volume and changing the substrate. Likely maintenance will include sediment accumulation removal, conveyance system and discharge structure repair, and vegetation harvesting or burning.
