All of the equipment and materials used to build roads in Benton County are kept at the Benton County Public Works Department on the east side of Avery Park. The first fall rains produce murky brown runoff, as can be seen in the picture above. The stormwater runoff from 2.3 acres of the property area previously flowed, without treatment, into the local Mill Race that connects with the Marys River and Willamette River downstream. The runoff is now intercepted by the 3,300 square foot OSU-Benton County Green Stormwater Infrastructure Research Facility, an Oregon Best Lab, that was designed and constructed by a collaborative effort between Oregon State University and Benton County. Construction of the facility was completed in early October of 2014. The total project cost was approximately $125,000, with funding support from the Oregon Water Resources Department, Benton County, the Pacific Northwest Transportation Consortium, Oregon Built Environment and Sustainable Technologies Center, and the City of Corvallis.

The facility consists of an underground storage tank, a concrete sediment bay, and three stormwater treatment cells. The 1,500 gallon storage tank intercepts runoff from the site’s existing underground stormwater pipes. A small 1/3 horsepower effluent pump that sits at the bottom of the tank transfers the water into the sediment bay. Large particles are allowed to settle in the sediment bay before entering the three treatment cells. Water from the bay cascades over the weirs into the cells, where it is slowed down, stored, and filtered by the soil and the plants.

The cells were designed to enable researchers to test different natural and artificial stormwater treatment technologies by removing existing materials and replacing them with different types. They were all constructed identically with a liner, an underdrain pipe for outflow, and layers of rock, sand, and soil. Currently, one cell contains a mix of native plants, another a mix of native grasses, and third with a synthetic LilyPad filtration technology made by Puralytics. The engineered soil mix consists of the site’s native silty clay loam, compost, and organic material to maximize pollutant treatment. The facility is outfitted with various monitoring equipment for scientific research conducted by OSU. The results from the research at the site will help to inform future stormwater treatment installations in Benton County and beyond. Drs. Meghna Babbar-Sebens and Arturo Leon are the co-directors of research at this facility. Questions related to research or facility use should be directed to Dr. Meghna Babbar-Sebens.