Denver — The American Public Works Association (APWA) selected the Tacoma Central Wastewater Treatment Plant Flood Protection Project for one of its 2016 Public Works Project of the Year Awards in the Disaster/Emergency Preparedness category. Presented at the APWA Annual Awards Recognition Ceremony on August 29 in Minneapolis, the award recognizes excellence in the management and administration of public works projects.
Located on the west bank of the Puyallup River in the Tacoma tideflats floodplain, the City of Tacoma's Central Wastewater Treatment Plant (CTP) is protected by a series of levees. Due to increasing risk of overtopping of the levee system, the CTP was at risk from flooding and required sandbagging to keep the plant in operation during severe wet weather conditions.
To mitigate this risk, CH2M worked with the City of Tacoma's Environmental Services Department to provide flood protection by designing a floodwall with automatic gates at vehicle entrances and an emergency pump station inside the CTP. The floodwall is 2,500 feet in length and effectively provides groundwater cutoff by extending up to 25 feet below ground and up to 8 feet above ground, providing flood protection to the currently unprotected perimeter of the CTP.
Serving as Primary Consultant for the project, the CH2M design team, in a resourceful collaboration with the Environmental Services Department and the primary contractor, and with the support of Tacoma mayor Marilyn Strickland and Pierce County Executive Pat McCarthy, brought the project to fruition within budget and two months ahead of schedule.
"Earning the APWA 2016 Public Works Project of the Year Award is a testament to the successful completion of this project. By working closely with our Tacoma client, we were able to exceed the stated goals for the effort, including installation of high-quality flood protection infrastructure, completion within the contract period and contract amount, and an extensive stakeholder outreach/partnership program," said CH2M Global Water Business Group President Peter Nicol.
The CTP serves as the single most important component of the city's wastewater infrastructure, treating approximately 80 percent of the wastewater from the citizens of Tacoma. The facility treats an average of 30 million gallons per day of wastewater during wet weather seasons and is capable of receiving and treating more than 130 mgd during major storm events. Continued operation of the CTP during storm events is key to continued environmental protection of the Puget Sound.
This is one of several awards the project has won recently, including the Northwest Construction Council Best Public Project under $10 million, and APWA Washington State Project of the Year in the category of Emergency/Disaster Preparedness.