ICL North Idaho Director, Brad Smith collecting a water quality sample in Boyer Slough

The Boyer Slough station has been monitored since 2013. It is the most highly polluted site that we monitor as shown by consistently elevated levels of total phosphorus, total coliform bacteria, and total nitrogen which can lead to toxic algae outbreaks and the growth of invasive weeds. These elevated levels are primarily attributed to the discharge of treated wastewater from the Kootenai Ponderay Sewer District (KPSD) into the slough for a significant portion of the year. With proper treatment, this discharge could have a limited impact on water quality; however, KPSD’s current treatment plant is incapable of treating sewage at a level that is protective of water quality.

In spite of their inability to effectively treat waste, KPSD persists in offering connections to new residences and businesses. We are urging the district to halt the addition of new connections until KPSD upgrades their treatment facility or connects to Sandpoint’s system.

Along with working on short-term solutions, ICL is invested in this clean-up effort for the long run. We are participating in a Kootenai Bay Watershed Advisory Group that aims to clean up this highly polluted area of Lake Pend Oreille. The group, which was convened by the Idaho Department of Environmental Quality, also includes a representative of the sewer district. We are hopeful that together, we can write a new plan that restores this waterway to a swimmable, fishable, drinkable condition – especially as new challenges lie ahead. In the meantime, swimming in the slough is strongly discouraged.

Homeowners can follow these tips to help improve the water quality along Boyer Slough.

  • Avoid disturbing the soil near the shoreline. In Bonner County there is a minimum 40-foot setback required where buildings are not allowed and retaining native vegetation is recommended. Bushes and trees can serve as a buffer between the lawn and the water’s edge.
  • Don’t over-fertilize your lawn and garden. If you use fertilizer, choose a phosphorus-free variety. Phosphorus is fuel for algae and aquatic weeds and can make them grow out of control – making our water unsafe.
  • Keep leaves and other yard debris away from the shoreline and storm drains.
  • Don’t let oils, chemicals, dirt, and other pollution spill into the water or storm drains.
  • Do what you can to divert stormwater so it soaks into the ground soaks before it runs into the lake.
  • If you have a septic system, make sure it is operating correctly. Panhandle Health District recommends having systems inspected every three years.