Calcium magnesium acetate (CMA) is used as an anti-icing chemical by the Oregon Department of Transportation (ODOT) in roadway winter maintenance programs. The effect of this chemical on the water quality of small streams directly adjacent to roadsides has not been well documented. Therefore, the use of CMA for winter maintenance in environmentally sensitive settings has been hindered. The project will help answer some of the unknowns by measuring the effects of CMA use along Highway 26 on the water quality of Bear Creek, a small creek in the Sandy River Basin that receives drainage from approximately 0.5 mi of Highway 26 on the south side of Mt. Hood.
The results of this study will be used to determine whether further study of the issue is warranted. If the water-quality parameters measured indicate the potential for a substantial environmental impact resulting from the application of CMA, then a second phase of the study involving biological surveys and assays will be developed.
The U.S. Geological Survey (USGS) will work in cooperation with ODOT to determine whether the use of CMA under ODOT's normal operating procedures results in a quantifiable effect on water quality (as measured by dissolved oxygen, pH, conductivity, biochemical oxygen demand, and major ions) in a small stream receiving runoff from a nearby roadway.
The study approach has two components:
Establish a temporary (fall and winter wet season) gaging station at the Bear Creek site. At the same location a four-parameter water quality monitor will be installed. Continuous stage, velocity, water temperature, pH, specific conductance, and dissolved oxygen data will be collected at Faubion Loop Bridge every 15 minutes. Stage and velocity data will be used to compute discharge on a near real-time basis.
Collect water-quality samples at the site three times over the course of the fall and winter, coordinated with ODOT's application of CMA.
REPORTSThe Effect of Calcium Magnesium Acetate (CMA) Deicing Material on the Water Quality of Bear Creek, Clackamas County, Oregon, 1999, By Dwight Q. Tanner and Tamara M. Wood. Abstract | Online version of report
U.S. Department of the Interior | U.S. Geological Survey