KPSD receives funds to clean up Boyer Slough

The Kootenai Ponderay Sewer District recently received the funding to clean up the Boyer Slough after it became polluted with runoff from the district.

According to the Idaho Conservation League, the slough is the most highly-polluted site that the organization monitors, with significantly elevated levels of phosphorus and nitrogen. 

“These elevated levels are primarily attributed to the discharge of treated wastewater from the Kootenai Ponderay Sewer District into the slough for a significant portion of the year,” ICL’s website said.

In June 2018, KPSD was issued a National Pollutant Discharge Elimination System permit that required better water quality in the Boyer Slough. 

“The permit allows year-round discharge to Boyer Slough with different effluent limits for the critical summer season — June through September — and non-critical season — October through May,” a 2020 KPSD report said. “However, critical season effluent limits for continuous phosphorus discharge are not achievable with any known [reasonable] technology; therefore, discharge to Boyer Slough during the critical season is not possible.”

According to the report, the current lagoon water treatment system is not designed to adequately remove ammonia or nitrogen. Additionally, the treatment system cannot keep phosphorus levels at or below 9 micrograms per liter — the required limit per the permit. The last recorded levels in 2023 were sitting around 60 micrograms per liter, according to ICL studies.

“The existing wastewater treatment facilities cannot meet discharge limits established in the 2018 … permit without significant upgrades,” the KPSD report said. “The district has been given until August 31, 2028 — 10 years from permit issuance — to comply with these new limitations under a compliance schedule. The compliance schedule allows continued operations while the district plans and constructs upgrades.”

After consideration by the district’s board members, it was determined that the lake outfall option would be the best alternative plan moving forward. Lake outfall would require moving the surface water discharge location to Lake Pend Oreille.

“Although the details of the lake outfall option must be thoroughly vetted, moving the discharge to the lake — rather than continuing to discharge to Boyer Slough — could be a valid alternative,” KPSD’s report said. “The lake discharge is expected to be structured for no net decrease in lake water quality.”

Three-year lake studies and sampling results were taken in partnership with the Idaho Department of Environmental Quality to ensure adequate water quality testing was being done. However, after the tests were completed in 2021, it was deemed that lake outfall was not the proper route to take.

“DEQ indicated that the district has not been approved for deep-water outfall discharge in the lake,” a March 2024 update on the KPSD website said. “At this juncture, the district has determined the most viable option available to the district to attain compliance with the new permit is to construct a mechanical plant as well as improvements to the current reuse site.”

ICL North Idaho director Jennifer Ekstrom said the district began looking to apply for funding to begin the upgrade project, which will cost approximately $32 million.

“The district currently anticipates the receipt of Leading Idaho Funding grant funds in the estimated amount of $13,771,044,” a May 6 update on KPSD’s website said. “The district anticipates utilizing a bond or loan to finance the remaining project costs of approximately $18,228,956.”

With the proposed repayment plan of the bond, the district anticipated that families would see an increase to their bill of roughly $5.49 to $8.24 per month. The issue was placed on May primary ballots to be voted on by the county. If the ballot failed, the district would have been at risk of losing its anticipated grant money, requiring them to cover the entire $32 million cost on their own.

This would potentially result in higher costs for residents throughout the county.

However, heavily increased rates did not have to be considered, as roughly 73% of the voters approved of the bond, while only 26% voted against it.

“Our work to safeguard the great lakes of North Idaho seeks to minimize pollution and ensure they remain swimmable, fishable and drinkable,” Ekstrom said. “We are very pleased that Kootenai Ponderay Sewer District raised the funds they need in order to upgrade their facility. Now we look forward to the upgrades being completed and are hoping to see water quality improve in Boyer Slough, which is currently severely polluted.”

The sewer district has roughly four more years to complete the cleanup of the slough.

In the meantime, ICL is focusing its efforts on the City of Sandpoint’s sewer treatment plant.

“It’s long been understood that this aging facility must be upgraded,” Ekstrom said.

Sandpoint recently agreed to pay a $3,450 fine for violations of the Clean Water Act, including exceedances of pollution limits for e.coli and chlorine, Ekstrom said, and have since announced that fixing the treatment plant is its number one priority.

“ICL is hopeful that this small fine will serve to expedite the city’s effort to fix the treatment plant, solving the problem at its source,” she said.