Last modified 2 years ago Last modified on 2017-11-06 09:37:03

Discharge from moving boat ADCP transects

We have done transects with TRDI Rio Grande ADCP, to get discharge and index velocity measurements. Nick Stasulis from USGS Water discipline in ME came to MOF(10/23-24) and gave us the training on how Water discipline does these measurements. We learned there are some useful methods to make the results better in shallow tidal situations.

  • edge must have minimum of 2 good bins, hold edge for 10 ensembles
  • in the WinRiverII configuration, set the depth so that the result is very close to the actual bottom depth
    • as the tide changes, stop pinging, and modify the settings to reflect the new water depth
  • transducer depth is set to midlle of transducer face
  • do the system tests, compass calibration at the site as the ADCP will be used, check temperature
  • do Moving Bed tests periodically as the tide changes- there might be Moving Bed issues at peak flows.
    • stationary is a better choice for us (not loop)
    • center of channel, every twelve (12) transects
  • Bottom track is usually the Best source of position, but for us GPS is often better (have to use if moving bed)
    • output both GGA and VTG (with a GP identifier, WinRiverII won't accept IN) +3hz refresh at 19.2 or faster baud
  • try to get 4 transects in a "measurement", at the time when a bottom mounted uplooking current meter is measuring.
    • our datasets with 30-40 transects in a "measurement" will need to be broken up to accurately capture the tidal changes
  • in super shallow (<1m) situations, a streamPro or riverRay system would do better (borrow from HIF?)
  • QRev has some powerful features for working with the transect data, but often going back to WinRiverII is needed.

Materials provided by Nick Stasulis (New England Water Science Center, Augusta Office)have been place in the Isntrument Library under RD Instruments\references\2017 ADCP Refresher