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ESTIMATING PEAKING FACTORS WITH POISSON RECTANGULAR PULSE MODEL AND EXTREME VALUE THEORY

by ZHANG, XIAOYI

Abstract (Summary)
The peaking factor (PF) is the ratio of the maximum flow during some specified time interval to the average annual flow. The PF concept has been used in both the drinking water and wastewater industries for nearly a century. Since there is uncertainty in the magnitudes of the maximum flow and the average annual flow, both can be treated as random variables and the corresponding PF should be interpreted in a probabilistic sense. Conventional methods for estimating the PF are based on empirical deterministic expressions, derived from a combination of field measurements and engineering judgment. While existing PF expressions have performed well, they lack a firm theoretical basis. The objective of this study is to combine results from the Poisson Rectangular Pulse (PRP) model for residential water use with principles from extreme value frequency analysis to develop a theoretical reliability-based estimate of the PF. Results show the theoretical PFs agree quite well with those from conventional empirical methods. The well-documented decrease in PF with network size is readily explained. The incorporation of indoor and outdoor water use and leakage makes its general application possible. The new PRP-based theoretical results are significant because they provide a direct way to estimate the PF in instances where flow data are scarce or where service area conditions may be changing.
Bibliographical Information:

Advisor:

School:University of Cincinnati

School Location:USA - Ohio

Source Type:Master's Thesis

Keywords:peaking factor extreme value theory peak demand water distribution system poisson rectangular pulse model

ISBN:

Date of Publication:01/01/2005

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