Geomorphic Model Archive, Kootenai River near Bonners Ferry, Idaho, 2011-2022, model archive

Between 2011 and 2018, numerous restoration treatments were constructed in the Straight and Braided and Straight Reaches of the Kootenai River in northern Idaho as part of the Kootenai River Habitat Restoration Project. Led by the Kootenai Tribe of Idaho, the project aimed to address a range of anthropogenic impacts inhibiting natural recruitment of the critically endangered Kootenai River white sturgeon (Acipenser transmontanus) and other native fish species. This data release contains information for two analyses used to assess the impact of the restoration treatments on channel morphology, flow depths, flow velocity, the extent of pools, and suspended sediment transport within the study reach.
Two-dimensional hydraulic model archive:
The two-dimensional (2D) hydraulic flow model International River Interface Cooperative with the Flow and Sediment Transport with Morphological Evolution of Channels solver (iRIC FaSTMECH) was used to investigate the impacts of habitat restoration treatments on hydraulic conditions in the Braided and Straight Reaches of the Kootenai River near Bonners Ferry, ID. The treatments were constructed between 2012 and 2018. Topographic surfaces from 2011, 2020, and 2022 were used to simulate hydraulic conditions before and after restoration treatments were built. Three different flow conditions (discharge and downstream water surface elevation) from the 2020 spring snowmelt hydrograph were simulated on a 5-meter model grid with the topographic surfaces for 2011, 2020, and 2022, producing a total of nine unique simulations. Flow depths, depth-averaged velocity, and area associated with each model grid node were exported for each simulation.

Measured suspended sediment concentrations and estimated tributary discharge:
The potential impact of the construction projects on suspended sediment entrainment within the Braided Reach was investigated through analysis of measured suspended sediment concentration (SSC) at two US Geological Survey (USGS) streamgages that bracket the study reach. To test for temporal trends in measured SSC (total, fine, and sand fractions) at both streamgages, multiple linear regression models were developed with SSC as a function of the independent variables time and estimated discharge from tributaries between Libby Dam and the study reach. Tributary discharge was used rather than Kootenai River discharge because Libby Dam has high sediment trapping efficiency and SSC in the Braided and Straight Reaches is driven primarily by tributaries between Libby Dam and the Below Moyie site.