Hells Canyon Complex Water Quality

Hells Canyon Complex Water Quality

Current Status:

Date Filed:
Jul 23, 2019

Case Title:
Nez Perce Tribe v. Oregon Department of Environmental Quality, Petition for Judicial Review

Staff attorney(s):
Lizzy Potter


Nez Perce Tribe

To Protect:

Clean Water

Fish Habitat

Date won/settled:
August 31, 2021


Case Information:

August 31, 2021 – The Nez Perce Tribe reached a settlement agreement with the state of Oregon resolving a case that Advocates for the West filed—along with the Tribe’s Office of Legal Counsel—challenging the state of Oregon’s Clean Water Act section 401 water quality certification for the relicensing of the Hells Canyon Complex. The Hells Canyon Complex, owned and operated by Idaho Power Company, consists of three dams and reservoirs on the Snake River that straddle the Oregon/Idaho border.

July 23, 2019 – Advocates for the West teamed up with the Nez Perce Tribe (Tribe) to file a challenge to the Oregon Department of Environmental Quality’s (ODEQ) May 24, 2019, Clean Water Act  certification for Idaho Power Company’s Hells Canyon Complex Hydroelectric Project (Hells Canyon Complex). Located within the Tribe’s aboriginal homeland, the Hells Canyon Complex, consisting of Brownlee, Oxbow, and Hells Canyon dams, is situated on the Snake River on the south end of Hells Canyon on the Oregon/Idaho border. 

The Hells Canyon Complex—constructed more than six decades ago on lands used by the Tribe since time immemorial—has caused extensive and irreparable injury to the culture, traditions, economy, and health of the Tribe and its citizens. The Tribe secured its inherent rights to resources in the area in the Nez Perce Treaty of 1855 and has co-management responsibilities at Hells Canyon Dam for juvenile Snake River spring Chinook and steelhead releases.

The Hells Canyon Complex blocks fish passage for the Tribe’s culturally-significant resources, including salmon, steelhead, Pacific lamprey, bull trout, and white sturgeon. The Hells Canyon Complex also and degrades water quality and habitat for these resources, and is believed to generate highly toxic methylmercury that bioaccumulates in the Snake River’s aquatic food chain. In 2015, the Tribe was forced to adopt a white sturgeon consumption moratorium for tribal citizens due to health risks posed by the presence of high levels of methylmercury in the Snake River downstream of the Hells Canyon Complex.  The Hells Canyon Complex also delays downstream cooling of the Snake River in the fall. ODEQ’s current Clean Water Act certification does not require Idaho Power Company to address its production of methylmercury and fails to ensure that Snake River water temperatures during fall salmonid spawning won’t exceed Oregon’s water quality standards for temperature. 

The original 50-year license issued to the Hells Canyon Complex by the Federal Energy Regulatory Commission (FERC) expired in 2005. Before FERC can issue what may be a new 30- to 50-year license to Idaho Power Company, ODEQ must certify, under the Clean Water Act and Oregon state law, that the Hells Canyon Complex’s activities will not violate Oregon’s water quality standards. The Tribe’s petition alleges that ODEQ’s certification is deficient because it does not require fish passage as mandated by Oregon law and the certification fails to provide reasonable assurance that the Hells Canyon Complex will not violate Oregon water quality standards for methylmercury and temperature during the life of the new license.