environmentally significant trends in water quality were detected
through visual assessment of the data.
· Fecal coliforms at times exceeded the site-specific objective designed to permit drinking water use after partial treatment and disinfection. It appears that complete water treatment and disinfection are needed, and that consumption during spring freshet should be avoided.
· Periphyton chlorophyll-a (a measure of attached algal growth) consistently exceeded the site-specific objective to protect recreation and aquatic life. Dissolved phosphorus levels were elevated, indicating an ample supply to support algal growth.
· Non-filterable residue (suspended solids) and turbidity were often elevated during spring freshet, and site-specific objectives were regularly not met. Turbidity removal (complete water treatment) and disinfection or remediation are needed before drinking water use.
· The pH was slightly high for drinking water, possibly affecting chlorination effectiveness and causing encrustation and scaling.
· The river was well buffered against acid and metal inputs.
· Hardness levels during the winter were poor for drinking water aesthetics, but still tolerable.
· The variables that exceeded criteria during spring freshet were: aluminum, chromium, copper, iron, manganese, titanium and zinc. These metals were largely associated with high levels of turbidity and suspended sediments, suggesting that they were in particulate form, probably not biologically available, and would be removed by the drinking water treatment needed to remove turbidity.