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HF002

Attribute: METHOD

code  description    
area    Velocities are averaged within fixed zones of known area in trapezoidal flumes - takes advantage of known dimensions and angles of the flumes and very accurate measurements of depth from hookgages     
average    Velocities are taken at varied positions and depths using velocity meters and averaged over the total area of flow     
bucket    Low flow procedure measures the time to fill a container of known volume     
calculate    Rating points are calculated retrospectively for the early WS09/10 v-notch using v-notch stage height with corresponding discharge calculated from main flume stage height and rating equation immediately preceding or following v-notch installation/removal    
cumul_slope    Cumulative slope method is a version of the "area" method as applied to Mack Creek flume so that specific angles and dimensions of the uneven side walls can be accounted for     
derived    The derived method uses a bucket measurement with the v-notch installed to calculate discharge for the main flume stage value immediately preceeding or following v-notch installation/removal     
difference    The difference method was used for an early version of the Mack Creek fish ladder rating curve by using the difference in discharge in the main flume directly before and after the flow gate to the fish ladder is opened     
dye    Dye dilution method injects a known concentration of fluorescent dye (Rhodamine WT) at a constant rate upstream and uses the dilution of the solution after mixing to determine discharge     
flume_hg    Rating tables developed from direct flume height measurement and velocity head rod serve as a means for determining discharge for hookgage measurements based on simultaneous flume height measurement     
usgs    USGS method is a version of the published current-meter method where velocity meter measurements are taken at regular intervals across the stream section to represent the area of that measured interval     
velocity    Velocity is calculated from several depth readings using a velocity-head rod, where the difference between flume depth and the hydraulic jump in depth along the flat edge of the rod are used to calculate velocity