Source: Washington State Department of Agriculture news release
Washington State's Snohomish River just downstream from French Slough is once again meeting state water quality standards for fecal coliform and dissolved oxygen, according to Washington State Department of Agriculture (WSDA) testing.
French Slough was directly impacted by a large manure spill last week and continues to show evidence of water quality problems.
A 21-million-gallon manure lagoon on the Bartelheimer Brothers dairy failed on April 11 or 12, releasing an unknown quantity of untreated waste across farm fields and into French Slough. The slough empties into the Snohomish River approximately 1.5 miles downstream from the spill site.
WSDA collected numerous water samples both upstream and downstream of the spill site on Friday. The samples were analyzed for fecal coliform bacteria that can cause illness in humans and dissolved oxygen content that fish require to breathe through their gills.
Fecal coliform tests show that water from the Snohomish River just below French Slough was found to have 24 colony forming units (cfu) per 100 milliliters of water. The tests also showed 9.6 milligrams of dissolved oxygen per liter of water (mg/L). The state water quality standard is below 100 cfu for fecal coliform and above 9.5 mg/L for dissolved oxygen.
Water samples taken from the French Slough pump station below the spill site show 240 cfu for fecal coliform and 5.6 mg/L for dissolved oxygen. Upstream of the spill site in French Slough, fecal coliform is 20 cfu and dissolved oxygen is 7.6 mg/L.
Snohomish Health District has received no reports of human illness related to the spill and no public drinking water sources are at risk from the spill.
No fish kills have been observed in the slough or the river. Juvenile salmon and steelhead trout may be present this time of year.
The dairy continues to work to mitigate the environmental impact of the manure lagoon collapse. On Friday, the dairy located and blocked another drain that was allowing manure to flow into French Slough. WSDA continues to work with the dairy to assess site conditions and monitor the dairy's containment activities.
In addition to conducting an investigation of the lagoon failure, USDA Natural Resources Conservation Service (NRCS) will be providing technical assistance to the dairy. The agency will assess field vegetation, sample soils and make recommendations to prevent further run-off of manure from the site.
Ecology's Dam Safety Office will also be conducting its own independent investigation into the failure. Ecology continues to monitor slough and river conditions.