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Temperature TMDL Replacement: Umpqua River Basin

TMDL title: Temperature TMDLs for the Umpqua River Basin (North Umpqua, South Umpqua, and Umpqua Subbasins)
Water Quality Limited Parameters: Temperature
Pollutants: Heat
Schedule: The U.S. Environmental Protection Agency is assisting DEQ to establish a revised temperature TMDL for the Umpqua River Basin by Feb. 28, 2025.
Project Area: This TMDL project includes the applicable area within the North Umpqua Subbasin, the South Umpqua Subbasin and the Umpqua Subbasin.

The project schedule for all replacement temperature TMDLs is online. To stay informed of this possible schedule change and other project related information, please sign up for email updates on our main TMDL Replacement Project page

Project summary

In 2013, the United States Environmental Protection Agency disapproved the Natural Conditions Criterion contained in Oregon's water quality standard for temperature due to the 2012 U.S. District Court decision for NWEA v. EPA, 855 F. Supp. 2d 1199 (D. Or., 2012). This portion of the temperature water quality standard was used in most temperature TMDLs issued from 2003 through 2012. On Oct. 4, 2019, the U.S. District Court issued a judgment for NWEA v. EPA, No. 3:12-cv-01751-HZ (D. Or., Oct. 4, 2019) and required DEQ and USEPA 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 water quality standard. 

A Total Maximum Daily Load is a water quality restoration plan and the calculation of the maximum amount of a pollutant that a waterbody can receive while still meeting water quality standards for that particular pollutant. The maximum amount of loading a waterbody can receive is called the loading capacity. Loading from all pollutant sources must not exceed the loading capacity of a waterbody, including an appropriate margin of safety.

Quality Assurance Project Plans: Umpqua River Basin

A Quality Assurance Project Plan is developed prior to writing the TMDL and does the following:

  • Defines the issue and objectives of the TMDL, including the spatial and temporal extents of the water quality impairments 
  • Provides a high-level description of the key processes and variables for temperature
  • Outlines the overarching technical approach for the TMDL, including the appropriate modeling and analytical tools to be used
  • Provides the data sources for defining and creating inputs to the models, including data that were used in the modeling for the original TMDLs, if an original exists 

Examples of these inputs can include meteorological data, stream flow and temperature, point sources and vegetation characteristics.

  • Describes how the analysis and modeling will be evaluated for acceptability
  • Describes potential scenarios for evaluating management strategies for reducing anthropogenic thermal loads
  • Provides various aspects for managing the TMDL development project, including documentation, the project team, data, and records management

View the Umpqua River Basin Interactive Map

Public process

DEQ and EPA are holding webinars about temperature Total Maximum Daily Load development for the Umpqua River Basin. The first webinar will take place in April and is an introduction to how EPA will revise the TMDL.

Umpqua Temperature Replacement TMDL Meeting #1

April 23, 2024

Water quality officials with DEQ and EPA hosted a webinar on April 23, 2024, and detailed how the agencies plan to revise the temperature TMDL for the Umpqua River Basin. The presentation included TMDL development, public involvement, and schedule.

Next steps

Webinar  #2 – June or July 2024

Webinar #3 – August or September 2024

Estimated EPA public comment period – Oct. 1 to Nov. 15, 2024

EPA to issue final TMDL by Feb. 28, 2025 

DEQ contacts

Sarah Sauter
Basin Coordinator 

Steve Mrazik
Watershed Management Manager

Ranei Nomura
Manager - Wastewater and Individual Permits

envelopeGreen.gif Sign up for email updates on TMDLs.

EPA contacts

Jenny Wu
Watershed Section Manager
206- 553-6328

Rebecca Veiga Nascimento
Technical Lead