Estimating Mean Velocity in Mountain Rivers
Publication: Journal of Hydraulic Engineering
Volume 111, Issue 4
Abstract
It is often necessary to estimate the mean velocity in ungaged mountain rivers, but the flow resistance equations available for this purpose require further testing and development. Such rivers are characterized by coarse bed materials, steep slopes, and low depths. For these conditions, boulders protrude well into or completely through the flow, and bed roughness is said to be large‐scale. Recently, three equations specifically intended for large‐scale roughness have been developed to address this problem. Data from a mountain river were used to test the equations. All were prone to errors of the order of 30%. The errors were systematic, all the equations tending to overestimate mean velocity compared to observed values. An investigation of the possible sources of error suggested that sampling error in the knowledge of bed material size was a major source of uncertainty in the predicted velocities, but that this and discharge errors could not wholly account for the observed discrepancies. Boulder shape is not represented in the equations, but this was discounted as an important parameter on the basis of a flume study. It was concluded that further research is required to produce a reliable, process based, flow resistance equation for mountain rivers.
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References
1.
Bathurst, J. C., “Flow Resistance of Large‐Scale Roughness,” Journal of the Hydraulics Division, ASCE, Vol. 104, No. HY12, Proc. Paper 14239, Dec., 1978, pp. 1587–1603.
2.
Bathurst, J. C., Li, R. M., and Simons, D. B., “Hydraulics of Mountain Rivers,” Report No. CER78‐79JCB‐RML‐DBS55, Civil Engineering Department, Colorado State University, Fort Collins, Colo., 1979.
3.
Bathurst, J. C., Li, R. M., and Simons, D. B., “Resistance Equation for Large‐Scale Roughness,” Journal of the Hydraulics Division, ASCE, Vol. 107, No. HY12, Proc. Paper 16743, Dec., 1981, pp. 1593–1613.
4.
Gessler, J., “The Beginning of Bedload Movement of Mixtures Investigated as Natural Armoring Channels,” Translated by E. A. Prych, Translation T‐5, California Institute of Technology, Pasadena, Calif., 89 pp.
5.
Hey, R. D., “Flow Resistance in Gravel‐Bed Rivers,” Journal of the Hydraulics Division, ASCE, Vol. 105, No. HY4, Proc. Paper 14500, Apr., 1979, pp. 365–379.
6.
Hey, R. D., and Thorne, C. R., “Accuracy of Surface Samples from Gravel Bed Material,” Journal of Hydraulic Engineering, ASCE, Vol. 109, No. 6, Proc. Paper 18047, June, 1983, pp. 842–851.
7.
Judd, H. E., and Peterson, D. F., “Hydraulics of Large Bed Element Channels,” Report No. PRWG 17‐6, Utah Water Research Laboratory, Utah State University, Logan, Utah, 1969.
8.
Kellerhals, R., “Runoff Routing through Steep Natural Channels,” Journal of the Hydraulics Division, ASCE, Vol. 96, No. HY11, Proc. Paper 7666, Nov., 1970, pp. 2201–2217.
9.
Lacey, G., “Uniform Flow in Alluvial Rivers and Canals,” Minutes of the Procedures of the Institution of Civil Engineers, Vol. 237, 1933–34, p. 421.
10.
Leopold, L. B., Wolman, M. G., and Miller, J. P., Fluvial Processes in Geomorphology, W. H. Freeman and Co., San Francisco, Calif., 1964.
11.
Limerinos, J. T., “Determination of the Manning Coefficient from Measured Bed Roughness in Natural Rivers,” U.S. Geological Survey Water Supply Paper 1898‐B, U.S. Govt. Printing Office, Washington, D.C., 47 pp.
12.
Thompson, S. M., and Campbell, P. L., “Hydraulics of a Large Channel Paved with Boulders,” Journal of Hydraulic Research, Vol. 17, No. 4, 1979, pp. 341–354.
13.
“Water Resources Data for Colorado,” U.S. Geological Survey Water‐Data Report CO‐80‐1, U.S. Geological Survey, 1981, 535 pp.
14.
Wolman, M. G., “A Method of Sampling Coarse River‐Bed Material,” Transactions of the American Geophysical Union, Vol. 35, No. 6, 1954, pp. 951–956.
15.
Zevenbergen, L. W., “Flow Resistance of Boulder‐Bed Streams,” thesis presented to Colorado State University, at Fort Collins, Colo., in 1982, in partial fulfillment of the requirements for the degree of Master of Science.
16.
Zevenbergen, L. W., discussion of “Accuracy of Surface Samples from Gravel Bed Material,” by Richard D. Hey and Colin R. Thorne, Journal of Hydraulic Research, ASCE, Vol. 110, No. 7, July, 1984, pp. 1016–1018.
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Published In
Journal of Hydraulic Engineering
Volume 111 • Issue 4 • April 1985
Pages: 612 - 624
Copyright
Copyright © 1985 ASCE.
History
Published online: Apr 1, 1985
Published in print: Apr 1985
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