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Title: Predicting internal roughness in water mains
Authors: Construction Engineering Research Laboratory (U.S.)
Walski, Thomas M.
Sharp, Wayne W.
Shields, F. Douglas
Keywords: Water mains
Pipe cleaning
Carrying capacity
Water distribution systems
Pipe networks
Pipe flow
Publisher: Environmental Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Series/Report no.: Miscellaneous paper (U.S. Army Engineer Waterways Experiment Station) ; EL-88-2.
Description: Miscellaneous paper
Abstract: A method is presented for predicting the Hazen-Williams C-factor for unlined metal water mains as a function of pipe age. The method has two steps: (a) finding the growth/rate of internal roughness, alpha, for the water main using either historical C-factor data or water quality data, and (b) using predictive equations for an estimate of a future C-factor. The predictive equations presented herein were derived using linear regression of some 319 data points from seven utilities as well as values from the 1920 text entitled Hydraulic Tables, by G. S. Williams and A. Hazen. The regression equations for C-factor as a function of pipe age have a 95-percent confidence interval of ±15 and a coefficient of determination (r) of 0.87.
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:Miscellaneous Paper

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