Culverts, bridges, and fords on perennial streams are considered stream channel alterations when used on logging roads and skid trails. They are regulated to safeguard stream crossings and protect water quality.

Several state and federal agencies oversee and manage Idaho’s waterways, including the:

• U.S. Army Corps of Engineers (Corps)
• Idaho Department of Water Resources (IDWR), and
• Idaho Department of Environmental Quality (IDEQ)

Stream channel alterations require an approved Stream Channel Alteration Permit (SCAP). All SCAP applicants must:

• Provide a description of their project, including the location by stream name, quarter/quarter, section, township and range, and latitude/longitude;
• Verify that the project will be installed and maintained in accordance with applicable regulations of the Stream Channel Protection Act and Idaho Forest Practices Act.

All new or reconstructed stream crossing structures in any fish-bearing stream must provide for fish passage. Any stream channel alteration project not installed or maintained to meet agency criteria must be removed.

Streamlined SCAP process for certain forest practices projects

To provide better service to Idaho forest landowners and managers, IDWR and the Idaho Department of Lands (IDL) have an agreement that allows IDL to administer and regulate the permit process “for stream channel alterations which are implemented as part of a forest practice.” Under this agreement, an approved Notification of Forest Practice (Notification) and Supplemental Notification Form (SNF) serve as your SCAP.

Forest practices projects qualifying for a SCAP under this agreement are known as “approved” forest practices projects. They are:

• Installation of round, squash, or pipe arch culverts, or bottomless arches, with 40 square feet or less of area on the open end of the culvert;
• Installation of culverts, less than 60 feet long, in non-fish-bearing perennial streams;
• Construction of bridges, 75 feet or less in length, on nonpublic roads, so long as the bridge does not require the placement of piers within mean high water marks, cause an encroachment of the stream channel with fill material, or cause wetlands to be filled;
• Construction or reconstruction of fords less than 75 feet in overall length and 25 feet in width; and
• Removal of perennial stream crossing culverts with 40 square feet or less of area on the open end.

Applicants must verify that the project is exclusively for forest practices activities. A failure to follow all requirements may result in an Idaho Forest Practices Act violation.

SCAP process for other projects

IDWR is responsible for processing SCAP forms for forest practices projects that do not meet the above criteria, as well as for all projects not related to forest practices that involve stream channel or wetlands alterations.

A Joint Application for Permit, with certification from the IDEQ, must be submitted to the IDWR/Corps for permitting (a SCAP/Corps 404 permit). A Joint Application is required when:

• Stream banks must be armored;
• In-channel structures are required to ensure stream stability in conjunction with the installation or removal of stream crossings;
• The project will involve use of machinery equipped with a blade or operation of machinery within the stream channel for stabilization, improving fish passage, or placement of woody debris for fish habitat; and/or
• State water quality standards cannot be met.

Which process must you follow?

The following questions will help determine which SCAP process applies to your project.

1. Will your structure cross a perennial stream?
   1. YES. Go to 2.
   2. NO. Go to 3.
2. Will you be conducting an approved forest practices project?
   1. YES. An approved Notification and SNF from IDL serves as your SCAP.
   2. NO. A SCAP/Corps 404 Permit may be needed for any stream crossing or wetland alterations. Submit a Joint Application to the IDWR/Corps.
3. Will you be conducting an approved forest practices project?
   1. YES. No additional permits are needed.

NO. A SCAP/Corps 404 Permit may be needed for any stream crossing or wetland alterations. Submit a Joint Application to the IDWR/Corps.