ARS | Publication request: Impact of submergence on parshall flume discharge measurements in low gradient headwater streams

Submitted to: ASABE Annual International Meeting
Publication Type: Abstract Only
Publication Acceptance Date: May 4, 2010
Publication Date: June 21, 2010
Citation: King, K.W., Fausey, N.R., Shedekar, V. 2010. Impact of submergence on parshall flume discharge measurements in low gradient headwater streams [abstract]. ASABE Annual International Meeting.

Technical Abstract: Accurate discharge measurements are critical to hydrologic design, water quality loading calculations, and rainfall/runoff studies. Generally measurement devices such as flumes and/or weirs are fabricated or commercially available and installed to facilitate discharge measurements. Development of stage discharge relationships for the flumes is generally based on theoretical documentation. However, much of this development is valid only under ideal conditions. Installation in natural streams or waterways is generally not ideal and the predefined rating curves are often compromised by naturally occurring phenomena such as siltation and submergence. Parshall flumes were installed in four low-gradient headwater streams (two located in channelized drainage ditches and two located in natural streams) to facilitate hydrologic calculations. Area velocity sensors were positioned at the throat on each of the Parshall flumes to provide velocity measurements for that cross section. Discharge measurements using the area velocity approach were compared to the theoretical discharge values and discharge values based on corrections for submergence. The results from this study will impact scientists and engineers relying on hydrologic structures for accurate discharge measurements.