Knife River Habitat Rehabilitation Phase II

The goal of PH II-Knife River Habitat Rehabilitation project was to improve instream habitat, stabilize slumping streambanks and restore the riparian tree canopy.

Site Selection:
The Lake Superior Steelhead Association (LSSA) conducted a rapid stream survey to determine the Knife River’s overall condition.  As stream impacts were identified during the survey, impaired stream reaches were photographed and mapped using a GPS unit.  The LSSA also monitored water temperatures to determine where trout survival is the highest.  Finally, biological data was collected to determine the quality of in-stream trout habitat.  This data was combined to rank and prioritize restoration areas where the worst stream impacts are restored, that reside in coolest water zones, within the best habitat corridors.  This data concluded that “first-priority reaches” were located in the upper main Knife River.  This also achieves our goal of a top-down restoration approach 

Riparian planting sites were determined by site accessibility and stream assessment using procedures listed above.  Specified project riparian species were determined by the existing riparian habitat, upland or wetland conditions and exposure to sunlight.

Restoration Techniques:
Natural Channel Design (NCD) utilizes a science-based process to bring an unstable eroding stream reach back to a stable state.  This method surveys an impacted stream reach to collect data to compare it to several stable stream sections.  All survey work is performed using a geomorphic trained Stream Specialist.  The assessment data that is collected includes: stream width to depth ratios, floodplain elevation, erosion calculations, longitudinal profile, cross-section elevation and vegetation cover.  This assessment data is entered into a computer program called Geomorph to create plans and specifications that will redesign the impacted Knife River channel profile, dimensions and shape to mimic stable reaches within the Knife River Watershed. These plans create the basis for the construction project by depicting channel reconfiguration, placement of structures, location of streambed excavation, location and elevation of the floodplain and realignment of the channel.      

The LSSA’s NCD process also features a top/down restoration approach.  This approach extends the habitat corridor downstream in three ways:
•    Downstream habitats are protected because the upstream sediment load is reduced.   By stabilizing these upstream eroding banks, hundreds of tons of sediment will no longer discharge into the stream channel each year.  This discharged material will no longer fill pools and runs that are critical to rearing trout.
•    Instream trout spawning success is more productive.  When trout spawn they discharge their eggs into the gravel.  When sediment discharges during high spring flood events, these eggs or newly hatched trout become covered by settling silts and suffocate larval trout.  By stabilizing these upstream banks sediment discharge is greatly reduced, which generally aids trout production.
•    Newly constructed stream channels are reconnected to the floodplain.  These restoration projects reconnect the stream channel to the floodplains, which allows floodwaters to crest the bank and dissipate the current’s energy.  Floodwaters also become trapped and stored in associated floodplain wetlands.  This results in a lower velocity of floodwater and less volume of floodwater that discharges downstream.  This reduction of floodwater velocity and volume minimizes downstream erosion and habitat degradation. 

Riparian Zone Planting Projects:
•    The species of trees/shrubs being incorporated into the planting plan depends on the area to be planted.  Rehabilitating an abandoned beaver meadow will require species that can tolerate rather damp conditions and even periods of flooding.  The planting of higher elevations, which are not as wet and experience less flooding events, will utilize a wider array of species.
•    Wet area species include: white spruce, tamarack, swamp white oak, river birch, silver maple and speckled alder.
•    Higher elevation/dryer area species include: red pine, white pine, red maple, silver maple, bur oak, red oak, northern mountain ash and speckled alder.
•    Shrubs/Pollinator Species That Are Utilized: viburnum, red twig dogwood, black chokeberry, snowberry, downy arrow-wood, sand bar willow.
•    Several species listed above can be utilized in multiple planting locations.
•    The LSSA uses locally procured stock for all of our plantings.

Scope of Work:
•    In stream Habitat Work Area: For PH II of the Knife River Habitat Rehabilitation Project, we restored approximately 2200 linear feet of stream on the main Knife River using the NCD processes.  Included in the area was the rehabilitation of largest slumping clay bank above Lake County Hwy 11.  This bank alone deposited tons of sediment downstream annually.
•    Riparian Zone Work Area: We performed planting projects on the main stem of the Knife River and tributaries-the Main West Branch and Stanley Creek.  We planted both low areas and higher ground areas using the species mentioned above.

Project Successes:
•    In stream Habitat Work: Immediately following construction (and even during the project construction) trout were seen utilizing this stretch of river, ranging from young of the year to spawning adult ages.  Sediment being transported and deposited downstream or even out in Lake Superior has been lessened with the project.
•    Riparian Zone Work: We planted many hundreds of trees in PH II creating a diverse riparian zone for years to come.

Unique Aspects of the Project:
•    Instream Habitat Work: One unique feature of our project is that we contracted with area loggers to bring in toe wood for areas where designated on the design plans.  Some groups prefer to take as much of the needed supplies from the work zone (toe wood, rocks, etc) but this increases the impact on the environment.  The LSSA tries to be as minimally intrusive on the stream and the riparian zone as possible in the project area.  All material that has to be removed for the project is 100% reincorporated back to the project area.
•    Riparian Zone Work: The LSSA tried carrying in tree plugs to very remote areas in five gallon buckets.  We found that you could carry almost 50 plugs in one bucket to far removed planting sites much easier than individually potted trees.  This process worked best on areas that had recent beaver activity but the beaver had moved on and the dams had been breached.