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Rain Gardens

A Low Impact Development Technique (LID) that uses vegetative habitats to naturally remove runoff pollutants

 Rain gardens are a low impact development (LID) technique that utilizes shallow impoundments of native vegetation and soil filters to treat stormwater runoff from developed areas. Rain gardens, also referred to as bioretention cells, are typically constructed in close proximity to the area to be treated. Stormwater is collected in the shallow impoundments and filtered through a soil media to remove pollutants. Based on the infiltration capacity  of the surrounding soils, these systems can naturally infiltrate or be underdrained.

Wright-Pierce Experience

As part of the site design and engineering for a 200,000 square foot industrial facility, a number of stormwater management techniques were incorporated to take advantage of site conditions and provide protection for receiving waterbodies including a nearby river, associated tributaries and a delineated vernal pool. The installation of  bioretention cells at several locations within the facility, including the facility entrance, were incorporated into the design to provide stormwater treatment and add visual interest. The bioretention cells were constructed on a 6-inch ponding area overlying an 18-inch soil filter layer. The systems were underdrained due to native soils in the area.  Plantings within the bioretention cells included native perennial species and shrubs.  In accordance with permit requirements, Wright-Pierce staff completed construction inspections during excavation, media installation, stabilization and plantings.

Rain gardens, also known as bioretention cells, are low impact development techinques routinely used as stormwater management measures in site design.