DEQ has begun a project to revise multiple temperature TMDLs that were issued by DEQ and approved by EPA between 2004 and 2010. DEQ is under a court order to update and replace these temperature TMDLs to make them consistent with the current temperature standards. These TMDLs must be updated because they were based, in part on the Natural Conditions Criterion, a section of the temperature standard that was subject to litigation and has since been disapproved by EPA.
The following temperature TMDLs are being replaced:
Additionally, DEQ is updating the following TMDLs for temperature:
- Upper Sucker Creek TMDL (1999)
- Lower Sucker Creek TMDL (2002)
- Lobster Creek Watershed TMDL (2002)
- The Little River Watershed TMDL (2001)
Visit DEQ's TMDL page for more information on what TMDLs are and what they include.
In 2012, The U.S. District Court found that EPA’s approval of an element of Oregon’s water quality standard for temperature, the Natural Conditions Criteria, was unlawful. The Natural Conditions Criterion stated that where the natural thermal potential of all or a portion of a water body exceeds the biologically-based numeric temperature criteria in OAR 340-041-0028(4), the natural thermal potential temperatures supersede the biologically-based criteria, and are deemed to be the applicable temperature criteria for that water body. This portion of the temperature water quality standard was effective from 2003 until EPA disapproved it in response to the court decision in 2013. Information about temperature standard litigation is online. Many temperature TMDLs were based on this criteria, and this became the subject of a second lawsuit brought by the Northwest Environmental Advocates against EPA asserting the EPA unlawfully approved TMDLs that were based on the now disapproved Natural Conditions Criterion. The court issued a judgment on Oct. 4, 2019, requiring DEQ and EPA to replace 15 Oregon temperature TMDLs that were based on the Natural Conditions Criterion and to reissue the temperature TMDLs based on the remaining elements of the temperature criteria. Cumulatively, these TMDLs address over 700 temperature impaired segments that do not meet water quality standards for temperature. DEQ’s role is to develop and issue these TMDLs and submit to EPA for their action over an eight-year period.
Per the District Court’s final order and judgement, DEQ must amend and submit replaced temperature TMDLs to EPA for approval or disapproval. The TMDLs will be replaced according to the following schedule (updated Sept. 24, 2020):
Jan. 15, 2024
Southern Willamette Subbasins*
Lower Willamette, Clackamas, and Sandy Subbasins*
*This TMDL will exclude the Willamette River mainstem and major tributaries. TMDLs for the Willamette River mainstem and major tributaries will be developed and issued for EPA’s approval or disapproval by Feb. 28, 2025.
Feb. 28, 2025
Willamette River mainstem and major tributaries
Tributaries included in the Willamette mainstem and major tributaries project area:
- Willamette River from the confluence of the Columbia River including the Willamette Channel and the Multnomah Channel to confluence of Coast and Middle Forks (approximately river mile 187)
- Clackamas River up to River Mill Dam/Estacada Lake (approximately river mile 26); Santiam River (all 12 miles)
- North Santiam River up to Detroit Dam (approximately river mile 49)
- South Santiam River up to Foster Dam (approximately river mile 38)
- Long Tom River to Fern Ridge Dam (approximately river mile 26)
- McKenzie River to confluence with the South Fork McKenzie River (approximately river mile 56)
- South Fork McKenzie River to Cougar Dam (approximately river mile 4)
- Blue River to Blue River Dam (approximately river mile 1.9)
- Middle Fork Willamette to Dexter Dam (approximately river 17)
- Fall Creek to Fall Creek Dam (approximately river mile 7)
- Coast Fork Willamette to Cottage Grove Dam (approximately river mile 30)
- Row River to Dorena Dam (approximately river mile 7.5)
North Umpqua Subbasins
South Umpqua and Umpqua Subbasins
Apr. 17, 2026
- Applegate, Illinois, Lower Rogue, and Middle Rogue Subbasins
John Day River Basin
Upper Rogue Subbasin
June 4, 2027
- Snake River - Hell's Canyon
- Lower Grande Ronde, Imnaha and Wallowa Subbasins
- Middle Columbia-Hood, Miles Creeks
May 29, 2028
Walla Walla Subbasin
Willow Creek Subbasin
Malheur River Subbasins
Note: The data solicitation closed on Oct. 30, 2020.
To support the replacement of these temperature TMDLs, DEQ will be conducting an open data solicitation starting July 1, 2020, through the end of the day, Oct. 30, 2020. During the solicitation period, the public may submit temperature data to DEQ in the watersheds subject to the temperature TMDL replacements.
For questions about the data solicitation, email: tempTMDLdata@deq.state.or.us.
What is the data going to be used for?
The primary use of the data is to characterize stream temperatures in watersheds where DEQ must revise the temperature TMDLs. Specifically, the data may be used to characterize temperature patterns and variation over both spatial and temporal scales and determine where exceedances to the temperature water quality standards occur and the magnitude and duration of those exceedances. Depending on the location and time period the data were collected, the data may be used to support the temperature modeling analysis. The modeling analysis helps DEQ understand the sources of temperature warming and what actions will reduce that warming. DEQ will highlight the years and waterbodies where temperature data will be extremely useful. In most cases, DEQ will make data submitted publically available in our Ambient Water Quality Monitoring System database.
Data quality and submission guidelines
Data availability and priorities
TMDL development and implementation is a public process. That means DEQ will work to keep the public informed and will consider their concerns and ideas. Each project TMDL will include a local stakeholder advisory group to provide information and feedback on the TMDL during development, as well as a web page for each TMDL with meeting materials and project updates. DEQ will incorporate environmental justice practices to make participation as open and accessible as possible. Additionally, DEQ will have a formal public comment period where anyone can provide comments. DEQ will develop a response to comment document that will be available to the public.