Sucesses and Challenges in One River's TMDL Saga

One of the nation's first TMDLs was established in the Tualatin River of Oregon. In the 1800s, settlers to the Oregon Territory grew crops of berries, fruits and vegetables, and later wine grapes, on the forested plains west of present-day Portland. One hundred years later, different human demands brought in companies like Intel, Tektronix and Nike, and an eclectic mix of suburban tracts and high-tech manufacturing supplanted many of the farms and forests. Ammonia and phosphorous were killing the river as it carried wastes from homes, factories and fields. Then in 1988, two Clean Water Act lawsuits forced the Oregon Department of Environmental Quality to develop a TMDL-driven watershed restoration plan for the Tualatin.

Over the next decade, an aggressive sewage treatment program significantly reduced pollution in the river, although phosphorous remained a concern. The maximum amount of phosphorous was set for the entire watershed. Agriculture, forestry, the sewer agency and the state Department of Transportation were given responsibility for helping meet the limit.

After 10 years the total amount of phosphorous from stormwater discharge was still about five times higher than the TMDL for the entire watershed. The state and local sewer agency responded by developing a plan to refine the existing TMDLs for phosphorous and ammonia and to develop additional TMDLs for temperature, bacteria and pH. The Tualatin Riverkeepers, a citizen's group, organized forums to help the public get involved in efforts to reduce pollution from new and existing development.