Proposed rule
Rulemaking contact:
Michele Martin, 503-880-7737
The Snake River originates in the Greater Yellowstone Area in Wyoming and runs north across the Oregon-Idaho border until meeting with the Columbia River. The scope of this TMDL will focus on a portion of the Snake River from where it meets the Oregon-Idaho border to the Washington-Oregon-Idaho border. There are three privately owned hydroelectric dams in the project area; Brownlee Dam, Oxbow Dam, and Hells Canyon Dam, which collectively are known as the Hells Canyon Complex.
Monitoring data show temperatures in the Snake River are too warm for sensitive fish and do not meet Oregon's EPA approved temperature standards. As a result, the Snake River and Hells Canyon Complex reservoirs have been placed on a national list of impaired waters. The federal Clean Water Act requires states or EPA to develop a Total Maximum Daily Load, or TMDL, for each water listed as impaired. Once approved, the updated TMDL will replace the temperature-related requirements in the June 2004 Snake River – Hells Canyon TMDL and Water Quality Management Plan.
DEQ is replacing the 2004 Snake River Hells Canyon temperature TMDL following the outcome from two court cases and related EPA actions. In response to a 2012 court decision, EPA disapproved Oregon's Natural Conditions Criterion for temperature in 2013, which had been used in most temperature TMDLs from 2003 through 2012. A 2019 court ruling then required DEQ and EPA to replace 15 TMDLs using the remaining approved parts of Oregon's temperature water quality standard.