DEQ seeks comment on draft 401 water quality certification for Kootenai River bank stabilization project

Accepting comments from April 21, 2025, through May 12, 2025.

The Idaho Department of Environmental Quality (DEQ) is seeking comment on a draft water quality certification for the Kootenai River bank stabilization project.

The proposed project entails the construction of a riprap revetment (protective layer) to prevent against erosion and stabilize the bank. The slope will have a maximum 1.5 feet horizontally to 1 foot vertically (1.5:1 ft.), with a mattress depth of 4 ft. The materials will have a D50 of 2 ft., meaning 50% of the particles, by weight or volume, will measure 2 ft. or less. Approximately 289 cubic yards (cy) of riprap will be placed below the ordinary high water mark (OHWM), including around 202 cy situated below the existing streambed, resulting in a net total of 87 cy below the OHWM. Excavators and dump trucks will be the primary equipment for this project. Best management practices will be employed to prevent soil from entering the river during construction, and additional measures may be implemented to address seasonal runoff.

Based upon review of the federal ​permit​ application, readily available water quality related materials, and certification request in accordance with 40 C.F.R. §§ 121.5 (b) and (c) and 121.7 (c), DEQ, certifies that if the permittee complies with the terms and conditions imposed by the federal ​permit​ and the conditions set forth in this water quality certification, then it is reasonable for DEQ to conclude that the activity will comply with water quality requirements, including applicable requirements of the Clean Water Act §§ 301, 302, 303, 306, and 307, Idaho’s “Water Quality Standards” (IDAPA 58.01.02), and other appropriate water quality requirements of state law.  

The draft certification is available for review on DEQ’s Public Comment Opportunities web page. Written comments will be accepted through May 12, 2025, at 5 p.m. Mountain Time. Submit comments electronically using the form below or by mail or email to: 

Tambra Phares
1410 N. Hilton St.
Boise, ID 83706
tambra.phares@deq.idaho.gov

Related Documents
Draft Certification


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