Capitol Highway Regional Stormwater Facility Design

Herrera designed four regional stormwater facilities to provide water quality treatment and flow control for planned street improvements. Winner of the APWA Oregon 2023 Project of the Year Award, the facilities are in residential neighborhoods with challenging constraints including: shallow perched groundwater, adjacent roadway embankments, steep slopes, wetlands and utility crossings. Herrera worked within these constraints to design and permit facilities that maximize stormwater treatment and flow control while enhancing habitat, stabilizing stream channels, and creating community amenities. Large wood, boulders, rock steps and channel armoring were used to stabilize an incised stream which would need to handle additional flows. Invasive vegetation was removed and upland and riparian areas revegetated including a large area for compensatory mitigation. Herrera also managed the work of subconsultants providing survey, geotechnical, and structural support for the designs.