DRA Releases 2019 Crooked River Water Quality Report

We are pleased to announce the release of the DRA’s 2019 Crooked River Water Quality Report.In 1998 the Crooked River was assessed and added to Oregon’s 303(d) list. The Clean Water Act § 303(d) list identifies waters that do not meet water quality standards and where pollutant load limits need to be developed through a total maximum daily load (TMDL) study. The TMDL study has yet to be completed. Since the initial listing in 1998, the Crooked River continues to exceed the State of Oregon’s water quality standards. A 2018 report by the Oregon Department of Environmental Quality assessed the water quality status and trends in the Crooked River basin. The assessment found that for the bacteria E. coli and total suspended solids things are getting worse. For water temperature, pH, and dissolved oxygen there has been no or minimal improvement since 1998 and the Crooked River does not meet water quality standards.

Photo by Rick Hafele

In 2019, the Deschutes River Alliance began monitoring water quality in the lower Crooked River.The key findings of our report are:• Water temperature and pH measurements exceeded Oregon’s water quality standards in the lower Crooked River (other parameters were not assessed during the study).• Modified flow regimes in the lower Crooked River impair the water quality in the reach between Bowman Dam and Smith Rock State Park. Water releases as presently managed from Bowman Dam are one factor. An additional factor is irrigation withdrawals directly from the river.• Large diel swings in pH were an indicator of excess nutrients (due largely to agricultural runoff) in contaminated water leading to prolific blooms of nuisance algae and excessive aquatic plant biomass.It is important to remember that these Crooked River pollutants need not be transferred from Lake Billy Chinook into the lower Deschutes River. For the first 50+ years of Round Butte Dam’s existence, all water discharged to the lower river came from the bottom of Lake Billy Chinook. Bottom water is nearly all Metolius River water, and therefore, much colder and cleaner than the Crooked River water at the surface of the reservoir.Please see our next blog to learn what this means for the lower Deschutes River.