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Nimz Ranch Tie Channel Velocity Mapping and Discharge Measurements, Kootenai River near Bonners Ferry, ID

January 11, 2021

Discharge measurements and velocity mapping surveys were completed at select tie channels located at Nimz Ranch, on the main-stem Kootenai River. Tie channels convey water and sediments between the main river channel and river floodplain waterbodies. The velocity mapping surveys are used to document how the tie channels interact with the main-stem Kootenai River. Similar surveys will be conducted following project construction completion (after 2021). Velocity mapping provides data to support the flow split estimates in the tie channel reconnection. These mapping efforts are a quantitative assessment of the the tie channels role in altering drift, temperature, and floodplain storage. An acoustic Doppler current profiler (ADCP) or acoustic Doppler velocimeter can survey select hydraulic characteristics of a flow field including: velocity magnitude and direction, turbulence, backscatter, and/or discharge. For channel discharge measurements, six transects were collected at pre-determined cross-sections to obtain an average velocity cross-sectional profile and corresponding discharge for the section. For general velocity mapping, the specified study area was discretized into representative zones which are measured a minimum of six times along multiple closely spaced sections to establish the dominant trend of velocity magnitude and direction within the zone. Data were processed using the Velocity Mapping Toolbox (Parsons and other, 2013) and smoothed using a neighboring nodes algorithm. These data are located in the zipped file below ( Data collected with an acoustic Doppler velocimeter are published in the summary spreadsheet (KootenaiR_NimzRanch_Vmapping_Qmsmt_Summary.xlsx). Naming convention for each cross-section corresponds to the measurement location. Main-stem cross sections are denoted as KR_NR_USMC_1 or KR_DR_DSMC_1 for upstream and downstream cross sections on the Kootenai River, respectively. Tie-channel cross sections connecting the Kootenai River to Nimz Ranch are denoted as KR_NR_USTC_1 (farthest upstream), KR_NR_USTC_2, KR_NR_USTC_3, and KR_NR_DSTC_1 (farthest downstream).

Publication Year 2021
Title Nimz Ranch Tie Channel Velocity Mapping and Discharge Measurements, Kootenai River near Bonners Ferry, ID
DOI 10.5066/P9R1O71M
Authors Taylor J Dudunake, Ryan L Fosness, Peter S Elliott, Deena F Green
Product Type Data Release
Record Source USGS Digital Object Identifier Catalog
USGS Organization Idaho Water Science Center