City will replace Dayton Avenue pump station
The city of Newberg will soon remove and replace the Dayton Avenue sewer pump system.
The lowest bid received for the project was for $1.3 million and was approved Jan. 2 by the City Council.
The pump station was built in 1993 and is the largest in the city. Although its rated capacity is 2,100 gallons per minute (gpm), recent testing indicated the pumps are operating around 1,350 gpm. The 1993 station replaced an older station that was constructed in 1985 that connected to an existing 12-inch PVC main pipe. The request is for an upgrade to 1,900 gpm and to install three 60 horsepower submersible pumps, as well as valves and piping. The old station will be destroyed and replaced with a new one, including a new sidewalk, curb, retaining wall and driveway.
The purpose of the project is to improve sewer service to the community and to reduce the risk of future sewage overflows into Chehalem Creek, which is a quarter-of-a-mile downstream from the pump station.
The station receives significant inflow and infiltration of rainwater, with several overflows reported, according to a May 2017 report.
City officials explained that the amount of wastewater that comes into the plant increases in the winter because storm water enters into the system. During heavy rainfall, the capacity of lift stations is sometimes exceeded and the excess overflows into area streams. This can happen through old and leaky pipes and has been a problem in the past, according to a June 2001 assessment.
Overflow from the pump station into Chehalem Creek is an issue because it is an environmentally sensitive area with delineated wetlands and a fish-bearing stream.
In March 2014, Newberg had a 50-year flood, subsequently the heavy rainfall resulted in two emergency discharges of untreated water into the Chehalem Creek and then into the Willamette River. One of the discharges was from the Dayton Avenue pump station. "We had 10 inches of water trying to be put into an eight-inch pipe and it just won't go," said Russ Thomas, the city's public works superintendent. "This was a very unusual rain event."
In 2015, the city attempted to resolve the issue by building the Highway 240 pump station to cut the flow from the Dayton Avenue station in half. The new station did help reduce the flow, yet some overflows continued to occur during heavy rainfall.
The project is expected to begin this summer and will improve the hydraulic performance of the system and provide a reliable wastewater conveyance for the community throughout the year, and during peak winter flow season, city officials said.