Stream Diversions

These activities require a Fish Habitat Permit (PDF 69 kB).

The following are typical procedures for temporary (short duration) stream channel diversions. Temporary diversions are often required for installing or replacing culverts, installing underground utility lines, or for similar reasons where a dry channel or work area is required.

  1. The diversion channel must be capable of carrying anticipated streamflows during the construction period.
  2. During excavation, the diversion channel must be isolated from the stream to be diverted at the upstream and downstream ends of the diversion channel.
  3. The bed and banks of the diversion channel must be constructed of material that will not erode at expected flows.
  4. Diversion of flow into the temporary diversion channel must be conducted by first removing the downstream plug, then removing the upstream plug, then closing the upstream end and then the downstream end of the natural channel and the diverted stream.
  5. Fish that become stranded in dewatered channels must be immediately captured and returned to the active channel without further harm.
  6. If a tributary stream enters the former channel within the diversion area, connect it in a suitable manner to the new channel.
  7. Fish passage in the temporary diversion channel must be maintained at all times, unless otherwise approved by the Division of Habitat.
  8. Rediversion of flow into the natural stream channel must be conducted by removing the downstream plug from the natural channel and then the upstream plug, then closing the upstream end and then the downstream end of the diversion channel.
  9. All man-made materials shall be removed from the diversion channel, the channel shall be backfilled, and stream banks stabilized.
  10. All disturbed areas shall be revegetated with naturally occurring woody plants and grasses if appropriate.

Sometimes permanent stream channel diversions are required to: reclaim lost fish habitat due to past mining activities, divert a stream around an active placer mine site, accommodate road and airport construction activities.

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Temporary Diversion Channel
Other Permitting Agencies Related Documents and Pages
Alaska Department of Environmental Conservation Fish Habitat Permit Application (PDF 69 kB)
Alaska Department of Natural Resources;
Division of Mining, Land and Water
Anadromous Waters Catalog
Catalog of Waters Important for the Spawning,
Rearing, or Migration of Anadromous Fish
U.S. Army Corp of Engineers Special Areas Permit Application (PDF 134 kB)
U.S. Forest Service Culvert Application (PDF 94 kB)
U.S. Environmental Protection Agency ADF&G Streambank Restoration Guide
Kenai Multi-Agency Permitting NOAA Habitat Restoration