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Implications of flume slope on discharge estimates from 0.762-meter H flumes used in edge-of-field monitoring

Open-File Report 2013-1082

Prepared in cooperation with the University of Wisconsin–Madison Discovery Farms program and the University of Wisconsin–Platteville Pioneer Farm program
By:
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Abstract

The effects of longitudinal slope on the estimation of discharge in a 0.762-meter (m) (depth at flume entrance) H flume were tested under controlled conditions with slopes from −8 to +8 percent and discharges from 1.2 to 323 liters per second. Compared to the stage-discharge rating for a longitudinal flume slope of zero, computed discharges were negatively biased (maximum −31 percent) when the flume was sloped downward from the front (entrance) to the back (exit), and positively biased (maximum 44 percent) when the flume was sloped upward. Biases increased with greater flume slopes and with lower discharges. A linear empirical relation was developed to compute a corrected reference stage for a 0.762-m H flume using measured stage and flume slope. The reference stage was then used to determine a corrected discharge from the stage-discharge rating. A dimensionally homogeneous correction equation also was developed, which could theoretically be used for all standard H-flume sizes. Use of the corrected discharge computation method for a sloped H flume was determined to have errors ranging from −2.2 to 4.6 percent compared to the H-flume measured discharge at a level position. These results emphasize the importance of the measurement of and the correction for flume slope during an edge-of-field study if the most accurate discharge estimates are desired.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Implications of flume slope on discharge estimates from 0.762-meter H flumes used in edge-of-field monitoring
Series title:
Open-File Report
Series number:
2013-1082
Year Published:
2013
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
Wisconsin Water Science Center
Description:
iv, 11 p.
Number of Pages:
20
Online Only (Y/N):
Y
Additional Online Files(Y/N):
N