The first Happy Hour of the autumn season featured two speakers who provided evidence-based information about our local waterways.  Robert Steed, IDEQ Water Ecologist, began the session with “TMDL Overview and the Spokane River,” followed by Mike Anderson, from the CDA Water Treatment plant, who discussed the facilty’s on-going improvements under construction this year.

Robert Steed works on collecting, analyzing, and studying water samples in order to determine how to set TMDLs—-Total Maximum Daily Loads—-for cadmium, lead and zinc.  A TMDL is a regulatory term in the U.S. Clean Water Act, which was passed to restore the country’s polluted waterways, and is the maximum amount of a pollutant that a lake, river, or stream can receive and still meet the water quality standards. Waterways may get pollution from point and non-point upstream sources. For instance, the metals in the lake and river are from the mining that occurred in the CDA River basin in years past.

Steed and his colleagues along with some area high school students, sampled water in the river to determine the loads of the three metals identified as problematic.  Cadmium is bad for aquatic organisms and could affect the food chain. However, cadmium seems to be at low enough levels to not worry about it, Steed thinks, based on this work. But both and lead and zinc pose a problem.  Lead levels spike in April during heavy flows and settle into the bottom at other times. Zinc surpasses safe limits often and will eventually be filtered out once the treatment plant upstream is built by the EPA cleanup project.

An audience member asked why mercury and arsenic had not been in the study, Steen said they had not been included, but he would look at adding arsenic in the future. Arsenic and mercury levels in fish have been studied in conjunction with the CDA tribe. They sampled 274 fish and arsenic did not exceed the criterion, but mercury did.  So there are fish advisories on the lake and river due to mercury contamination.

The CDA water treatment facility, Mike Anderson explained, is currently doing upgrades to deal with phosphorus and to plan for the future increased capacity needs as the city grows. Phosphorus acts as a plant fertilizer, which stimulates excess plant growth and causes oxygen depletion that harms other organisms like fish. One of the most important sources of phosphorus is the household garbage disposal!!  Compost your waste instead. The CDA treatment plant composts all its solids after treatment. The new system to stop phosphorus problems is partially operating now and should be fully operational by next year.

The CDA plant offers tours, which are very informative about this crucial job that protects the health and safety of our waters and our human health.  If you are interested in participating in a Wastewater Plant Tour please email for more information.