Surface & Stormwater
HWA's has over four decades of experience working on surface and stormwater projects, giving us extensive infiltration experience, both for stormwater and wastewater projects. Our wastewater infiltration design experience affords us a unique perspective on stormwater infiltration projects.
HWA served as lead geotechnical engineer for the City of Marysville Downtown Stormwater Treatment Project near Ebey Waterfront Park. The project included biofiltration vaults, pump station, and piping. HWA performed site explorations, lab testing, and engineering analyses. Due to compressible soils, HWA designed a preload surcharging plan to reduce settlement. The design also addressed slope stability. The project won the 2024 PNCWA Innovative Stormwater Project Award.
HWA provided geotechnical engineering services for the replacement of the box culvert below a busy City arterial with a fish friendly 4-sided box culvert. HWA provided recommendations for design and construction of the culvert and the associated wing walls. HWA also provided recommendations to provide protection against erosion for rehabilitation of stream both upstream and downstream of the new culvert and provided materials testing and special inspection during construction.
HWA provided a geotechnical engineering study in support of the proposed Washington Avenue Pump Station Relocation Project in Kent, WA. Field evaluations included site reconnaissance, advancing three cone penetrometer tests (CPT), and one geoprobe exploration within the footprint of the planned improvements. Engineering analyses were conducted to develop design recommendations for the design and construction of the pump station, flow meter structure, and associated piping.
HWA served as lead geotechnical engineer for the City of Marysville Downtown Stormwater Treatment Project near Ebey Waterfront Park. The project included biofiltration vaults, pump station, and piping. HWA performed site explorations, lab testing, and engineering analyses. Due to compressible soils, HWA designed a preload surcharging plan to reduce settlement. The design also addressed slope stability. The project won the 2024 PNCWA Innovative Stormwater Project Award.