POULSBO — Phil and Andrea Holt said they felt uneasy when the rain fell after the Nov. 19 storm caused a sewer main to overflow and flood their basement for the second time in five years.

It appears they and their neighbors can rest a little easier.

Poulsbo’s Public Works Department dug a trench, reinforced with a berm, at the base of the hill above Nordnes Street to capture any future overflow from the sewer main along Highway 305.

The state Department of Ecology looked into the trench and berm because they’re adjacent to a stormdrain that leads to Liberty Bay. During the Nov. 19 storm, Public Works employees pumped rain-diluted wastewater from the Holts’ basement into a stormdrain which leads to Liberty Bay, resulting in a six-day beach closure by the Kitsap County Public Health District.

“Unauthorized discharges of untreated wastewater from the sanitary sewer would violate state law, but the city’s overall efforts show dedication to preventing further releases of wastewater from this line to the stormwater system and the bay,” Larry Altose, spokesman for the Department of Ecology, told the Herald by email.

“Based on conversations with city staff, we understand that the city has constructed a berm to protect the homeowner from any possible overflow. The berm would direct overflow water to an artificial pond from which it would be possible to recover the flow before it enters the storm drain. The city is considering options for an early detection system that would alert public works staff to high flows within the manhole and piping system so that they can position a vacuum truck at this pond. Thus, if a sewage pipe at full capacity flows out of a manhole cover into the roadway and flows to the temporary detention pond, the city can pump out the pond so the wastewater would not continue into the storm drain system and to Liberty Bay. Ecology does not expect this to be a common occurrence …

“All of this suggests that Poulsbo is serious about preventing future untreated wastewater discharges while effectively protecting against more damage to people’s homes.”

Meanwhile, Public Works Director Barry Loveless said concerns raised in former city engineer Herb Armstrong’s 2008 study about the city’s sewer system’s ability to handle wastewater from the Olhava area development had been resolved when Olhava was developed. In that study, Armstrong cited a 1995 -letter by the city’s planning director stating that a new sewer main needed to be installed along Viking Avenue to Keyport Junction, connecting to a line that goes to the county’s wastewater treatment plant in Brownsville. Instead, a second sewer main was installed along Highway 305, running parallel to the original sewer main. Those sewer mains become one at Tollefson Road, a fifth of a mile from where the sewer main has overflowed twice in heavy storms since 2007. That sewer main carries all of Poulsbo’s wastewater to Johnson Road in Lemolo, then across Liberty Bay to Brownsville.

Loveless said a separate sewer main down Viking Avenue is still a “viable, long-term option.” He said the city’s Comprehensive Plan states the main would needed around 2030 if the city grows at its projected pace. According to the Comp Plan, the city’s population is expected to be 14,808 in 2025.“It’s not that it’s been discarded. The option is out there to handle future growth. But we still have capacity in our current line,” Loveless said.

Loveless said installing a sewer main down Viking Avenue would cost about $50 million and would require crossing Johnson Creek, a sensitive salmon stream. Another option is continuing that second sewer main all the way down 305 to Johnson Road.

Meanwhile, the city continues to work on getting the rainwater out of the city’s sewer system. Loveless said rainwater gets into the sewer system in several ways, among them vented manhole covers and antiquated stormwater connections that were used to flush the sewer system in the old days.

According to the Department of Ecology, “The city also is working on an engineering analysis to determine if measures can be taken to increase capacity within the existing pipes.”

The storm contributed to wastewater overflows elsewhere in Kitsap on Nov. 19. An estimated 100,000 gallons spilled into Port Washington and Sinclair Inlet. And Annapolis Public Beach was closed because wastewater was discharged that had received primary treatment and disinfection but bypassed secondary treatment.