Geneva Bioretention Pilot Project

This project aims to improve the water quality of runoff flowing into Lake Whatcom by reconstructing a series of underutilized bioretention swales in Whatcom County’s Geneva neighborhood using a novel dosing siphon flow distribution system and Ecology’s new High-Performance Bioretention Soil Media (HPBSM). Partially funded by an Ecology grant, the project tests whether the performance of HPBSM observed in the lab can be replicated in a large-scale treatment facility using the same specifications. Additionally, this project will serve as a case study for implementing the HPBSM specification, documenting the HPBSM material costs, procurement, and installation process. Construction was completed in November 2023, and facility monitoring is ongoing.