Description

The Prairie Line Regional Stormwater Facility is located near the corner of Hood St. and S. 21st St in Tacoma, WA. The facility, which is incorporated into a portion of the old Prairie Rail Line railroad spur, uses a treatment train approach to treat stormwater runoff from 42 acres. The treatment train is made up of two TAPE-approved treatment technologies – a hydrodynamic separator located at the upstream end of the facility which provides pretreatment by removing trash and larger debris followed by a vegetated media filter to remove sediment and heavy metals.

The stormwater facility was completed in 2014 and is a part of a historic art installation, part stormwater treatment. Between 1873 and 2003 the rail line was part of the Northern Pacific Railroad, which extended from Tacoma to the Great Lakes. The vegetated media filter component of the treatment train was designed to sit within the existing railroad tracks. As water infiltrates through the media pollutants such as sediments, nutrients, heavy metals, and oil and grease are removed through a combination of filtration, adsorption, and absorption. The vegetation aids in the treatment of the stormwater by helping to restore soil permeability through the uptake and transpiration of moisture within the media.

After leaving the facility the treated stormwater rejoins the City of Tacoma’s stormwater drainage system before being discharged into the Thea Foss Waterway.