Innovative Stormwater Management and Stream Relocation for a DOD Facility

Rain gardens and detention storage were designed and constructed for a new 50-acre military site, including relocation of a stream. The stormwater facilities were designed in accordance with Section 438 of the Energy Independence and Security Act. With a surface area of approximately 2-acres, the gardens provide over 5,200 cubic meters of storage for the 90-percent non- exceedence storm and detain over 3.40 cms during the 100-year storm. Two level spreaders distribute the basin effluent across a riparian buffer prior to reaching the receiving stream. Plunge pools designed at the inlets to the rain garden dissipate energy and settle out solids before entering the gardens. The new stream includes rock vanes, and pool and riffle sequences to mimic a natural stream.Designing the stormwater management facilities at the site was complex due to the close proximity to the existing stream, set elevations on the site, a high water table and accelerated design schedule. Early performance of the system indicates that despite the challenges, it is operating well under heavy rain events and aquatic animals have been spotted in the relocated stream.