Total Maximum Daily Load (TMDL)

It is a key strategy of Lane County to pursue programs and practices that reduce impacts on and leverage the natural environment to enhance livability and economic development. The County understands that maintaining and improving the quality of our natural resources are essential to protecting the future health and prosperity of the County.  Towards that end the County has developed cost effective standard operating procedures and practices that support improvement of our water resources. 

One way that we support the quality of our water resources is in our compliance with the Oregon Department of Environmental Quality (DEQ) requirements associated with Total Maximum Daily Loads (TMDL) for the Willamette River.  A Total Maximum Daily Load (TMDL) specifies the maximum amount of a pollutant that a water body can receive and still safely meet water quality standards. The Willamette River TMDL was developed by DEQ and approved by the EPA as authorized through the Federal Clean Water Act (CWA) of 1972.  The Willamette River is listed as being water quality limited for mercury, bacteria, and temperature in Lane County.

The Willamette River TMDL lists Lane County as a Designated Management Agency (DMA) or a municipality that has legal authority over activities or areas that are sources of pollutants.  Lane County’s DMA area is a total of 149 square miles, comprised of scattered parcels along the waterways within the Willamette Basin.

As a DMA Lane County initially developed our TMDL Implementation Plan to document pollutant reduction strategies in 2008. Our current Implementation Plan is available below.  Per DEQ requirements, Lane County updates our Implementation Plan every 5 years and completes annual reports to DEQ. 

Current Willamette River TMDL Implementation Plan
2014 TMDL Implementation Plan
2020 Willamette River TMDL Annual Report