19398

2002-002-00 FEASIBILTY OF ENHANCING WHITE STURGEON SPAWNING

8/15/2004

11/14/2006

156. Develop RM&E Methods and Designs

Work Element Usage Report

H: 156 - Kootenai River Pre-development Simulation

Simulate pre-development conditions in Kootenai River by modifying the multidimensional models of the white sturgeon spawning reach and the braided
reach.

This work element will be performed by the USGS.

Simulate pre-development conditions in the Kootenai River by modifying the multidimensional models of the white sturgeon spawning reach and the braided reach. This modeling effort will utilize the U.S. Geological Survey's MD_SWMS or another acceptable model. This task includes modifying the river channel bathymetry and topology in the spawning reach model and in the braided reach model. This modification will be accomplished by adding the valley floor to the models and by modifying the dikes so the natural river bank/levee is included in the channel topology. Data that will be used to modify the topology in both models includes the recently collected LiDAR data and the 1928 USGS topo map. The KTOI recently digitized the 1928 USGS topo maps. The modern channel bathymetry does not accurately reflect the bed morphology present during the pre-development era. The modern channel geometry will be modified as best as possible using historical data. Stage and discharge boundary conditions for model calibration are not available for predevelopment conditions because streamflow gages were not established till 1929, by then dikes were being constructed, wetland were being drained, and drainage districts were being developed to keep the valley floor from being inundated. The best available stage and streamflow data may be the earliest records from the gaging stations during the early 1930's before the dikes were completed and the draining of wetland completed. An alternate model will be developed if substantial difficulties arise during the construction and calibration of a predevelopment model because of insufficient topology or hydrologic data. This alternate model will be developed to simulate conditions during the pre-Libby Dam era when the dikes were completed and the drainage of wetlands complete. Due to the level of difficulty and uncertainty associated with this modeling effort, a peer review report is not planned during this contract period for this specific modeling task. Model results will not be available until a report is published. After successful completion of model construction during this contract period, a report can be prepared in a following contract period.
The pre-development model will provide a tool for the KTOI and other resource management agencies to estimate pre-development habitat conditions in the current spawning reach and braided reach. This modeling effort addresses needs listed in task 1B.3 in the SRT Implementation Plan (White Sturgeon Recovery Team, 2005): explore opportunities for restoration of suitable natural spawning and recruitment conditions through a combination of Kootenay Lake levels and Libby Dam discharges; and, historical conditions will serve as a reference point for identifying what factors have changed and what operations and habitat alterations may be necessary to restore parameters that were historically beneficial for sturgeon recruitment. Depending on the level of success in terms of model construction and calibration, task 3 may address activity 1B.3.1.b in the SRT Implementation Plan: comparisons of current and historical conditions will highlight specific changes in habitat associated with recruitment failure; and, a key question is whether current sturgeon flows encourage or discourage selection of upstream spawning sites. Task 3 may address activity 1B.3.1.c in the SRT Implementation Plan which focuses on identifying alternatives to optimize habitat conditions. Alternatives will be identified based on a model sensitivity analysis to different combinations of lake elevation and river discharge. One critical response variable will be the downstream location of the velocity transition zone relative to suitable rock spawning substrates. In addition, task 3 may address activity 1B.3.1.d in the SRT Implementation Plan which focuses on identifying other considerations which might constrain hydro operations of Kootenay Lake and Libby Dam for the benefits of sturgeon (levee soundness, lake flooding, power costs, other fish impacts). Fundamental physical changes in the Kootenai system means that it may no longer be realistically feasible to configure hydro operations to restore suitable sturgeon spawning conditions or that large scale changes will have significant costs. For instance, river confinement by levees will limit acceptable risks of high lake elevations or river flows. The modeling will assist scientists in identifying the effects of different operations on sturgeon habitat suitability.

$32,070

7.14%

10/16/2005

10/16/2006

10/13/2006

Concluded

[Unassigned]

[Unassigned]

Finite