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Follow the same principles used to site a conventional streamgage (Site Selection, p. 9; Turnipseed and Sauer, 2010):
Straight channels with parallel streamlines
Streambed free of large rocks, weeds, obstructions that would create turbulence/slack water
Sections that are parabolic, trapezoidal, or rectangular
Avoid variable flow conditions downstream of of piers or channel obstructions (Please please note it is important they we target surface scatterers to achieve sufficient radar returns, but highly turbulent conditions should be avoided)
Velocities greater than .5 to 1 feet per second (fps) and depths greater than 0.5 feet (ft)
Avoid sections influenced by tributaries or contributing drainage
Collect the following streamflow and channel data at the cross section-of-interest:
Station number and measurement number
Date of measurement
Width
Area
Mean-channel velocity
Gage height
Discharge
Lat/long of the starting and ending edge of water
Lat/long of the vertical (termed the “y-axis”) where the maximum in-stream or maximum surface-water velocity is measured
At the y-axis, record the surface-water velocity and point velocities near the water surface, close to the channel bottom, 0.2D, 0.3D, 0.4D, 0.5D, 0.6D, 0.7D, 0.8D, 0.9D using a current meter, FlowTracker, or Stationary Moving Bed Analysis with an ADCP
Confirm the location of the y-axis by repeating this procedure to the left and right of the y-axis
Water depth at the y-axis
Wind speed and direction
To estimate the stationing of the y-axis, rely on the location of the maximum-surface water velocity; it generally coincides at the same vertical as the maximum-instream velocity
Develop a stage-area rating using AreaComp (https://hydroacoustics.usgs.gov/indexvelocity/AreaComp.shtml)
Generally, data collection and radar deployments point should be upstream of bridges or structures to avoid wind-dominated reaches, eddies, secondary flows, and macro turbulence.
Velocity radars can be deployed by hand or fixed on bridges, light cableways, or cable stays
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