The City of Granite Falls will soon face a water quality emergency at its wastewater treatment plant (WWTP). The treatment plant discharges into the Pilchuck River, which is a component to the Snohomish Watershed. This water body is currently subject to the Washington State Department of Ecology’s Water Quality Implementation Plan to reduce the Total Maximum Daily Load (TMDL) in the river for Temperature and Dissolved Oxygen. The City’s population has increased by over 40% since 2017 due to new construction housing projects permitted before the City issued a sewer moratorium in April of 2018. Due to the significant population increase and the latest water quality TMDL study results for the Pilchuck River issued by the Department of Ecology, the City is now in a precarious situation. The TMDL results obligate the City to modify its effluent discharge permit limits for soluble phosphorus and temperature, and the treatment needed to comply with the new permit limits comes at a significant cost. Due to the confined nature of the facility site and the increased amount of sewage being treated daily, the City must also must completely modify the facility’s biosolids handing process, eliminating the composting of biosolids on site and converting to the processing and hauling of biosolids as sludge to authorized off site locations for land applications.
This WWTP upgrade project will support the vitally important objective of improving the water quality in the Pilchuck River watershed. It is imperative to support the recovery of threatened cold-water fish species that spawn, rear, or live there. Chinook, coho, sockeye, chum, pink salmon, bull trout, and steelhead trout call the Pilchuck River home. Many of our State’s residents greatly value these fish species and depend on them for cultural, recreational, or economic reasons. Washington State has targeted the Pilchuck River mainstem to restore endangered Chinook salmon (Snohomish Basin Salmon Recovery Forum, 2005). This wastewater project is essential to improving and protecting the future health of the river and the Snohomish Watershed.
Although the unfunded mandate to improve the water quality treatment process at the WWTP is the primary driver of the total cost of the this upgrade project, the rapid population growth within the Snohomish County region has also pushed the need for this expansion to provide additional treatment capacity sooner than expected, as the WWTP is now operating at nearly 100% capacity. Despite the schools being nearly vacant for over a year due to Covid-19, the WWTP saw daily flows and biochemical oxygen demand (BOD) loading at over 90% of its permit limit. With over 470 additional housing units added to the system in the past four years and schools opening in 2022, the daily flow volume and BOD loading at the WWTP have now reached their operating capacity and the City is currently in violation of its NPDES permit limits during high flow months of the year. This additional treatment capacity will allow the City to accommodate its mandated population target of 6,885 by year 2044 and it will address the critical need for additional affordable housing inventory in Snohomish County by eliminating the sewer moratorium that has prohibited new housing construction in the City since 2018.
The WWTP Upgrade is 100% designed as of March 15th, 2023 and is currently under review by Dept of Ecology. Pending confirmation of funding via a combination of a low interest loan from the state and requested grant funding from the Federal Government, the city could begin construction as early as July of 2023. If funding is secured and the project moves forward in the Summer of 2023, the expected completion of the project is slated for October of 2025. The total estimated cost of the project is $33 million dollars. The City has already spent $1.8 million on the design and have $2.5 million in capital reserves to put towards the construction of the project. The City currently has a pending loan offer from Washington State Department of Ecology Clean Water State Revolving Fund (CWSRF) for FY 2024 that is still subject to approval by the State Legislature to fund to majority of the project and has asked for $2.8 million from the Federal Government for $2.8 million to cover the gap in funding still needed to cover the entire cost of the project.
WHAT IS BEING DONE AND WHY IS IT SO IMPORTANT:
The Granite Falls Wastewater Facilities Plan (11/2018) & Amendment (6/2022) recommended improvements to the wastewater treatment and biosolids handling facilities at the Granite Falls Wastewater Treatment Plant (WWTP) to improve water quality in the Pilchuck River and to serve the City through 2038. The proposed project will construct the recommended WWTP improvements to provide wastewater treatment and disposal for the service area and meet the requirements of the facility’s NPDES Wastewater Facility Discharge Permit #WA0021130.
The primary purpose of this project is to support the vitally important objective of improving the water quality in the Pilchuck River watershed. It is imperative to support the recovery of threatened cold-water fish species that spawn, rear, or live there. Chinook, coho, sockeye, chum, pink salmon, bull trout, and steelhead trout call the Pilchuck River home. Many of our State’s residents greatly value these fish species and depend on them for cultural, recreational, or economic reasons. Washington State has targeted the Pilchuck River mainstem to restore endangered Chinook salmon (Snohomish Basin Salmon Recovery Forum, 2005). This wastewater project is essential to improving and protecting the future health of the river and the Snohomish Watershed.
Economically, lifting the sewer moratorium on new construction will provide living wage jobs directly and indirectly related to the housing construction industry for residents throughout Snohomish County and beyond. This new residential growth will, in turn, promote new commercial development in the area, which will create additional retail and service industry jobs to support local Snohomish County residents. Other indirect economic benefits of this project include increases in property tax, sales tax, and real estate excise tax for the region and the State.