Corral Creek Wetland and Riparian Restoration: Tee / Colby 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).
Private land and USDA Forest Service, Clearwater National Forest
Landowner (access and minimum 20 percent project match)
Bonneville Power Administration
Idaho Office of Species Conservation
/ Pacific Coast Salmon Recovery Fund
Idaho Department of Environmental
Quality / EPA Clean Water Act Funding
USDA Forest Service / Resource Advisory
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. Legacy effects of logging and associated construction of railroad spur lines, and later,
livestock grazing, had degraded water quality, impaired hydrology, and reduced pool habitat. A passage barrier downstream
had blocked spawning steelhead trout from accessing the upper 75 percent of the watershed since 1913, but after removal of
the barrier (2007), steelhead moved into the upper watershed the next spring (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 (Bowersox et al 2011b). During
logging operations in the early 1900's temporary rail lines, known as shay lines, were constructed throughout the meadows
of the Potlatch River Watershed. Using the shay lines, crews moved logs from the woods down into and through the meadows,
on to the main rail yards and rail lines, and eventually to the mills. The railroad berms persist throughout the Corral Creek
watershed, criss-crossing meadows. In many areas, the ditches associated with construction of the berms have captured the
stream flow. Early in the 1900's the flow of the East Fork of Corral Creek was diverted from its channel in the Tee and Colby
reaches, and was captured by borrow ditches associated with the shay lines and main line. This inadvertent straightening of
the stream channel degraded water quality and eliminated steelhead rearing habitat. The higher velocity of flow in the straightened
channel caused bank and bed erosion, adding sediment and degrading downstream water quality. Because of the deeper, straighter
channel, the connection with the adjacent floodplain was impaired and the water exited the system too quickly to allow historic
levels of infiltration and storage. The lowered water table led to a lack of woody riparian vegetation for shading and reduced
availability of material for woody debris recruitment for instream complexity. The existing private road through the meadow
adjacent to and through the creek increased soil compaction in the wet meadow and was steadily being eroded into the adjacent
ditch. Cattle trampling and scratching further denuded banks of vegetation and aggravated the ongoing erosion.
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.
A nearby tributary of Corral Creek, the West Fork Corral Creek, which is usually intermittent like the East Fork and mainstem
Corral Creek, retained water year-round when beavers were actively building and maintaining dams there in 2008. The restoration
design for this project was to mimic beaver dams in the ditch through Tee and Colby meadows, to detain flow in water impoundments
and increase recharge. In 2009 a series of channel or "ditch" plugs were constructed to create diversions and wetland
cells. By diverting the flow back into the shallower, more sinuous historic channel, the flow of the East Fork of Corral Creek
has been slowed, hydration of the meadow and frequency of flood events has increased in the meadow system, and because of
the pool habitat in the historic channel, habitat for juvenile steelhead was immediately improved. Wetland habitat was also
improved by converting the wide, deep, eroded ditch into a series of wetland cells, which further detains water in the meadow
system and increases recharge. Following construction, areas of bare soil were seeded with a mix of native grasses and forbs
and planted with native grasses, forbs, sedges, rushes, bulrushes, and woody species. All bare areas were stabilized following
seeding, using sedge mats or mulch. Sedge sod mats were particularly effective for protection of bare soil on the ditch
plugs, and provided both immediate erosion protection and speedy revegetation (see photos below). Over 12,000 square feet
of sedge sod mats were installed on ditch plugs as well as on other eroding sites where overtopping flows eroded portions
of the disturbed ground. A new road was included in the restoration plan to remove the traffic from the meadow, reducing compaction,
and further improving meadow vegetation and hydrology. Sedge mats were harvested during construction of the new roadbed, and
stored on-site until they could be laid on the ditch plug slopes. Livestock exclusion fencing was installed in 2010 to protect
the majority of the historic East Fork of Corral Creek and the newly-created wetland in Colby Meadow. To further draw the
cattle out of the meadow, the landowner selectively logged some of the adjacent timber ground to open the canopy and seeded
the slopes to improve forage in the uplands. Two ponds were constructed in the uplands in 2011 to provide water in order tofurther
draw and retain the cattle in the uplands. Planting continued for several years to revegetate construction areas, restore
the wetlands, and stabilize cutbanks. From 2009 through 2012, over 26,500 containerized plants and whips have been planted
to establish vegetation in disturbed areas and to enhance degraded riparian zones outside the construction sites. Photopoints
were established to document changes in vegetation and survival monitoring will highlight re-planting needs. Groundwater and
surface water elevations are also being monitored, both in the project area and in similarly-degraded meadow systems throughout
the Corral Creek watershed (Latah SWCD 2013). The plant community in Colby Meadow, where most of the wetland cells were created
in the ditch, is already showing an increase in hydrophilic plants.
construction, road construction, bridge installation, fencing, development of livestock crossings, and construction of ponds
are complete. Minor repair work was done in 2011 and 2012. Minor supplemental revegetation is scheduled for 2013. Function
of the structures will be monitored for several years into the future.
Bowersox, Brett, Regional Fisheries Biologist with Idaho Department of Fish and Game.
2008 pers comm.
B.J., R. Banks, and N. Davids. 2011b. Potlatch River steelhead monitoring and evaluation project - Annual report 2011. Idaho
Department of Fish and Game, Lewiston, ID.