Corral Creek Wetland and Riparian Restoration: Avulsion / Round Meadow Restoration
Steelhead Habitat Restoration
Corral Creek, a tributary of the Potlatch River, in Latah County, Idaho
and Limiting Factors
Corral Creek subwatershed is 14,300 acres,
approximately 4 percent of the Potlatch River Watershed, and includes predominantly forested and canyon stream types. Corral
Creek supports spawning and rearing habitat for ESA-listed threatened steelhead trout (Oncorhynchus mykiss).
Limiting factors include: high water temperature, high flashy stream flows, low summer base flows, lack of complexity in stream
composition, migration barriers, and sedimentation (Resource Planning Unlimited 2007).
(access and minimum 20 percent project match)
Bonneville Power Administration
Idaho Office of Species Conservation / Pacific Coast Salmon Recovery
Idaho Department of Environmental Quality / EPA Clean Water Act Funding
Problem: Limiting factors affecting steelhead habitat: high
water temperature, high flashy stream flows, low summer base flows, lack of complexity in stream composition, and sedimentation.
Low flow conditions during rearing, in particular, limit productivity. Legacy effects of logging, with associated construction
of railroad spur lines, and livestock grazing, had degraded water quality, impaired hydrology, and reduced pool habitat. After
a passage barrier downstream was removed in 2007, spawning steelhead trout regained access to the upper Corral Creek watershed,
including this reach (Bowersox pers comm). Improvement and expansion of spawning and rearing habitat for steelhead trout is
a priority in the Potlatch River watershed (Ecovista 2003, Resource Planning Unlimited 2007). Low flow conditions during rearing,
in particular, limit productivity. Between 2005 and 2008, Corral Creek in the Avulsion Reach experienced erosion events that
allowed the flow to be diverted from the narrow, sinuous, well-vegetated historic channel in to the ditch of an old road bed
associated with early 20th century logging. In Round Meadow, upstream of the Avulsion location, the flow had already
been captured in borrow ditches associated with the temporary rail lines known as shay lines, which were used to transport
logs. The straight, wide ditch sections enabled higher flow velocities, causing ongoing bank and bed erosion, adding sediment
and degrading downstream water quality, and allowing the flow to exit the system more rapidly than historic conditions.
Solution: Address limiting factors by returning flow to
sinuous, well-vegetated channel to reduce erosion, improve stream composition and shading, and restore meadow hydrology to
attenuate flashy peak flows, improve summer base flows, and reduce water temperature in pools through groundwater seepage.
In 2008 we began construction of channel plugs to divert the flow back into the shallower, more sinuous historic channel to
slow the flow through the meadow, increase hydration of the meadow, decrease erosion, and improve wetland habitat. By diverting
flow back into the historic channel, instream pool frequency and pool habitat complexity for steelhead trout was immediately
improved. In order to reduce erosion pressure on the main diversion channel plug, we diverted flow of a minor tributary northward
by cutting in a new channel. The ditch at Avulsion Reach was converted to a series of wetland cells, to further enhance infiltration.
Following completion of instream construction, all bare areas were seeded and mulched, or seeded, mulched and covered with
erosion control material, to stabilize the soil and prevent erosion. The seed consisted of a mix of native grasses and forbs.
The mulch is a weed-free pelletized straw product. Disturbed areas were also planted with a mix of native sedges, rushes,
bulrushes, forbs, and woody species. From 2008 through 2013, over 12,500 containerized plants and whips have been planted
to re-establish vegetation in disturbed areas and to enhance the riparian zone vegetation in undisturbed sections. Livestock
fencing installed in 2009 excludes cattle from the restoration area to allow establishment of the native vegetation and recovery
of the meadow vegetation. A livestock water pond was constructed in late 2011 to provide alternative water for the cattle
and to draw them upslope and away from the meadow to reduce compaction. The off-channel water also reduces bank trampling
and improves riparian vegetation along portions of the creek that remain unfenced. Photo points were established to
document changes in vegetation, and survival monitoring will identify replanting needs (Latah SWCD 2013).
Instream construction was completed in 2008. Minor repair work and revegetation
were completed in 2009 and 2012. The solar-powered watering system for the livestock pond was installed in June 2013. Other
than minor additional revegetation, as needed, the project work is complete. Function of the structures will continue to be
monitored for several years.
Ecovista. 2003. Clearwater Subbasin Assessment. Prepared for Nez Perce Tribe Watershed Division,
in cooperation with the Clearwater Policy Advisory Committee. www.nwcouncil.org
(Latah Soil and Water Conservation District). 2013. Monitoring Plan and Procedures, Draft. Moscow, ID.
Resource Planning Unlimited.
2007. Potlatch River Watershed Management Plan. Sponsored by Latah Soil and Water Conservation District. Moscow, ID.