Discharge Permits for Federal Hydroelectric Projects in the Lower Snake River

Below are EPA's National Pollutant Discharge Elimination System (NPDES) discharge permits for the following hydroelectric generating facilities on the lower Snake River operated by the U.S. Army Corps of Engineers:

• Ice Harbor Lock and Dam (WA0026816)
• Lower Monumental Lock and Dam (WA0026808)
• Little Goose Lock and Dam (WA0026786)
• Lower Granite Lock and Dam (WA0026794)

Effective date: April 1, 2022
Permits expire: March 31, 2027

EPA originally accepted public comments on the draft permits for these facilities from March 18 through May 4, 2020. The draft permits were then revised to include heat load effluent limits and again made available for public comments from January 15 through February 16, 2021. Copies of the comments we received during both comment periods are available below.

The final permits issued in September 2021 were modified in March 2022 to address typographical errors and the use of continuous data to calculate heat limits.

Related permits: Draft Discharge Permits for Federal Hydroelectric Projects in the Lower Columbia River

• NPDES Permit, Ice Harbor Lock and Dam, Lower Snake River, #WA0026816 (pdf) (March 7, 2022)
  Final discharge permit.
• NPDES Permit, Little Goose Lock and Dam, Lower Snake River, #WA0026786 (pdf) (March 7, 2022)
  Final discharge permit.
• NPDES Permit, Lower Monumental Lock and Dam, Lower Snake River, #WA0026808 (pdf) (March 7, 2022)
  Final discharge permit.
• NPDES Permit, Lower Granite Lock and Dam, Lower Snake River, #WA0026794 (pdf) (March 7, 2022)
  Final discharge permit.
• 2021 NPDES Permit Fact Sheet, U.S. Army Corps of Engineers Lower Snake River Hydroelectric Facilities: #WA0026816, #WA0026808, #WA0026786, #WA0026794 (pdf) (January 2021)
  Technical basis for 2021 revised permits.
• 2020 NPDES Permit Fact Sheet, U.S. Army Corps of Engineers Lower Snake River Hydroelectric Facilities: #WA0026816, #WA0026808, #WA0026786, #WA0026794. (pdf) (March 2020)
  Technical basis for 2020 proposed permits.
• Response to Comments on Draft NPDES Permits for Federal Hydroelectric Facilities in the Lower Snake River (pdf) (September 30, 2021)
  EPA's responses to public comments received on the 2020 and 2021 draft permits.
• Public Comments on 2021 Draft NPDES Permits for Federal Hydroelectric Facilities in the Lower Columbia and Snake Rivers (pdf) (March 1, 2021)
  Comments received by EPA within the public comment period from January 15 through February 16, 2021.
• Public Comments on 2020 Draft NPDES Permits for Federal Hydroelectric Facilities in the Lower Columbia and Snake Rivers (pdf)
  Comments received by EPA within the public comment period from March 18 through May 4, 2020.