KWL designed a new pump station and public washroom in China Creek North Park near Glen Drive and 7th Avenue, a popular public park in Vancouver, BC. With a section of sanitary forcemain, the project includes a bypass, pigging port and isolation valves to facilitate emergency maintenance, an alternate discharge line, or pipeline pigging. The pump station replaces an existing one constructed at the site in the early 1970s, reaching the end of its life. The building construction offered an opportunity to create a public washroom for China Creek North Park that was designed and constructed in tandem with the new pump station.
Odour management and mitigation were a top priority due to the popularity and location of the site. The HVAC and odour systems were designed based on a thorough review of the ventilation requirements set out in NFPA 820, Worksafe BC requirements, best practices, and overall life-cycle costs. A recirculation system was incorporated into the HVAC design to reduce the overall heating cost of the building, following the strict requirements of NFPA 820. An explosive gas monitoring system was also integrated into the station design to ensure worker safety.
The pump station design included external utility designs, including a new water service to building and park amenities. In addition, the inlet sewers were revised and reconfigured to provide a temporary bypass during construction. A new discharge forcemain that ties into the existing main sewer line and siphon was constructed. Site drainage is also an integral part of the project, with all-surface water and roof rainwater collected and managed using various stormwater management methods including an open rain garden with buried attenuation ponds and permeable paving.
The new station incorporated upgrades to the safety of operations and maintenance activities and station seismic resistance. In addition, the old underground station was replaced and reconfigured with a new wet well and pump room below ground, along with the above-ground electrical and maintenance building, improving overall station access and resiliency.
The new pump station was sized for an ultimate capacity of 204 L/s using 3-25 HP pumps. However, based on the hydraulic assessment completed by KWL, design flows for the next 30 years are anticipated to stay under 143 L/s. With these lower flows, the new station included installing 3-20 HP pumps to improve operational efficiency and reduce initial capital costs and station operating costs.
The Glen PS begins 8m underground. Micro-piling was used to access this depth, utilizing shotcrete and soil anchors to shore the temporary excavation. This material also formed a portion of the permanent structure of the building. This process increased safety and minimized external material and personnel requirements. In addition, the temporary shoring of shotcrete as a part of the permanent structure reduced the overall carbon footprint of the build as less concrete was needed overall.
The site is also located on a former landfill with excavation extending well below the groundwater table. Therefore, KWL required the contractor to have any groundwater removed from the excavation to be treated, settled, and discharged to the sanitary system.
KWL provided design services, including the initial hydraulic modelling and the mechanical, civil and electrical designs for this pump station. The geotechnical investigation and design were completed by Geowest Engineering, the structural design was completed by Gygax Engineering (GEA), and architectural services for the building and washrooms were provided by Stephane Laroye Architects (SLA); all sub-consultants to KWL. KWL, Geowest, GEA and SLA provided construction services to the City throughout construction, including site inspections and construction monitoring. KWL was the Contract Administrator for this project.