An important element of the U.S. Clean Water Act (CWA) requires that States establish water quality standards and monitor the health of water bodies. Water quality standards set limits for pollutants that impact the chemical, physical, and biological integrity goals. Streams like the Willamette River that do not meet water quality standards are listed and prioritized. A regulatory tool called a Total Maximum Daily Load (TMDL) is then developed to improve and protect listed streams. A TMDL is 1) a calculation of the amount of a pollutant that a water body can receive and still meet water quality standards; and 2) a method to allocate an acceptable load among the municipal and industrial dischargers along the water body.


Current TMDLs on the Willamette River in the vicinity of Corvallis include bacteria, mercury, and temperature. The City has strategies to address bacteria and mercury TMDLs and a plan to address the temperature component is being created through the TMDL Alternatives Evaluation Project. The City is also tracking new federal and State regulations that will likely result in stricter standards for traditional pollutants and new constituents found in some pesticides, cleaning agents, pharmaceutical and personal care products. Revised water quality standards will likely result in additional TMDLs.

The City's wastewater treatment plant discharges to the Willamette River and was not designed to remove constituents found in many consumer goods that we commonly use at our homes and businesses. The City estimates the cost of treating all these pollutants to expected water quality standards over the next 20 years to be over $100 million. An alternative to discharging wastewater from the treatment plant to the river may be recycling the treated water for irrigation or other suitable purposes. The City is currently in the process of evaluating these options with the goal to develop a long-term plan to address Willamette River TMDLs. Ideally, the ultimate solution will address the near-term temperature TMDL as well as future regulations for toxins and other pollutants. Based on initial evaluations, it is clear that no single solution will address our long-term wastewater management needs.

City staff have developed a public education and outreach process to alert the community to these pending issues facing the wastewater utility. The City is seeking the public's involvement in the process to develop a TMDL plan. We are doing so for many reasons, among which are that this community is very committed to environmental stewardship, that the final solution likely will drive an increase in rates paid by residents, and that more input will result in a better end product. More information about the project has been gathered in a Frequently Asked Questions (FAQs) document.

In 2009, the City hired a consultant to conduct a TMDL Alternatives Evaluation for the Corvallis Wastewater Reclamation Plant (WWRP) discharge to the Willamette River. The goal was to determine what it would take to comply over the long term with current and potential future regulations, to assess the economic impacts of these regulations, and to evaluate alternative options to the direct discharge of wastewater effluent into the Willamette River. This analysis resulted in three viable alternatives that now are being shared with the public and stakeholders as a starting point for the discussion we hope to have about this situation. The alternative ultimately selected by the City may be one of these alternatives, a combination of these alternatives or another alternative yet to be identified. A project summary has been developed with more information about each alternative.

We encourage you to get involved in this Alternatives Evaluation project. Join as at one of the outreach workshops to learn more and to share your thoughts about a workable solution to the TMDL regulations. Follow the project's progress as documented in the City newsletter articles. Share your thoughts directly with the City Council Urban Services Committee, or provide your input and comments to staff.

Last updated: 9/20/2012 12:19:08 PM