How do you install a bioretention cell?

There are specific plans with most project outlined by engineers and architects specific to each project’s landscape.  However, the general idea is to place a [perforated drainage pipe, usually with a filter sock along the bottom of a small pond dug along that collects the stormwater.  The pond is typically 4 to 6 feet in depth.  The drainage pipe discharges outside of the pond but also has a T or connection for a vertical standpipe that will be above the surface level of the pond for overflow discharge.  The underdrain system is typically filled with #57 gravel and lined with a geotextile liner.  Above the gravel and drainage system the bioretention soil mix is placed usually 36 to 48 inches in depth and covered with a mulch layer.  During the installation process machinery and other equipment must not be used to compact the bioretention soil as it is installed.  This can be done with excavators positioned from the edge, slinger trucks, or in a manner that starts in sections and works your way out of the pond.  Select native plants are planted within the pond to uptake moisture and nutrients retained.  The inlets are lined with concrete or rip rap to prevent incoming runoff from eroding the edges of the pond.