This project will replace the existing stormwater treatment system on Austin Street, between Cable Street and Morgan Street. The new system will utilize a newly-developed High-Performance Bioretention Soil Mix (HPBSM) to treat total suspended solids, dissolved copper, dissolved zinc, and total phosphorus. A Department of Ecology grant partially funds this project. After installation, the county will collect data and evaluate the performance of the new HPBSM media.
Engineer - Herrera Environmental Consultants, Inc.
Construction Contractor - To be determined
Construction Costs - Determined through a competitive bid
Replace failing system
Improve water quality
Development of a new treatment technology
The existing treatment facility along Austin Street was constructed circa 2008. Due to reports of flooding the system needed to be taken off-line. The system experienced uneven sediment distribution, sediment impedes infiltration through the media. Typical Bioretention soil is not recommended near phosphorus sensitive waters like Lake Whatcom.
The new system will install an impermeable liner to address the flooding downstream, will pre-settle the stormwater to reduce sediment entering the infiltration, and will distribute the flows more evenly throughout the treatment system. The system will use a new High Performance Bioretention Soil Mix (HPBSM) that is designed to be better at capturing phosphorus and other pollutants.