Let the Sediment Flow: Assessing the Resiliency of a River Restoration Project to Landscape-Scale Disturbance
Dakota Whitman, MS, GIT
SWCA Environmental Consultants
Whitefish, MT
Authors: Whitman, D., MS, GIT, Daniels, Matt., P.E.
Ball Creek is a second-order tributary to the Kootenai River near Bonners Ferry, in the panhandle of Idaho in Ktunaxa Territory. River Design Group, now part of SWCA Environmental Consultants, was contracted by the Kootenai Tribe of Idaho to assess and design a restoration strategy for lower Ball Creek as part of the Kootenai River Habitat Restoration Program. This was funded by the Bonneville Power Administration under the Northwest Power and Conservation Council’s Fish and Wildlife Program. The desired outcome of this project was to build a more resilient ecosystem capable of sustaining diverse native flora and fauna, with the ability to withstand natural disturbances and altered regimes. To achieve this, the design included stream channel reconstruction, large wood structures, floodplain reconnection and revegetation.
On September 10, 2022, the Russell Mountain Fire burned 11,531 acres of the Ball Creek Watershed – greater than 70% of the total drainage area above the project site. Shortly after the fire, high levels of precipitation induced an 8-acre mass wasting event upstream of the project site on a Forest Service road, leading to that road’s failure. This event significantly increased the fine sediment load downstream to lower Ball Creek, which is located on an alluvial fan in a depositional environment. The Spring freshet of 2023 mobilized the newly deposited fines downstream into the lower Ball Creek project area, providing a real-world example of how certain restoration approaches fare when faced with landscape-scale disturbances.
This presentation will describe the geomorphic effects that the Russell Mountain Fire had on designed channel morphology, as well as the response observed post-disturbance. Three years of monitoring data that occurred before, during and after the fire will guide discussion and analysis. This will touch on the topics of river restoration design techniques, sediment transport regimes on alluvial fan systems, and river restoration project resiliency to climate change.
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