WDFW's Environmental Restoration Fish Passage Section, previously known as the Technical Applications Division, has mapped off channel habitat sites for the Quillayute, Dickey, Sol Duc, Calawah, Bogachiel, Clearwater, and Hoh basins on the Olympic Peninsula and the Skagit basin and portions of the Stillaguamish basin in the North Sound.
The term “off-channel” is used to describe previously undocumented aquatic habitats with direct connection to the basin’s river network that are currently known or suspected to support anadromous salmon, char and trout. Generally, off-channel habitats are small tributaries, frequently spring or ground water-fed, that flow into larger channels. Their diminutive size has caused them to be overlooked in prior inventories and they don’t often appear on topographic maps. Although small, these waters can be very productive for salmonids. These species, especially coho salmon, are naturally attracted to these sites primarily for protected over-winter rearing. Some sites have spawning gravel, which allows adults to spawn and results in fry being able to rear in very productive habitat with high survival. Both coho and chum salmon are attracted to these sites for spawning where suitable gravel (or substrate) is available. Additionally, since they are frequently fed by spring or ground water, they usually stay wetted throughout the summer preventing summer stranding losses of parr common in more principal river channels that are surface-fed. Also, the scour of redds is reduced during winter freshets.
Location and description of these habitats was undertaken primarily for two purposes. The first was to identify these sites for their protection through various regulatory procedures and permits such as Forest Practice Rules, Hydraulic Project Approvals, Critical Areas Ordinances, zoning and other land use controls. A related value was to provide water typing information to Washington Department of Natural Resources that determines type and levels of acceptable activities in the vicinity. Knowledge of their existence can also allow them to be included in conservation easements, habitat purchases and similar protection measures. : Second, the off-channel surveys were used to identify enhancement opportunities such as improvement of fish access to natural off-channel habitat and potential sites for developing groundwater-fed channels and ponds. These ranged from access improvements to excavated ground water channels.
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