KWRRI Research Reports


Surcharge in a storm sewer system is the condition in which an entire sewer section is submerged and the pipe is flowing full under pressure. Flow in a surcharged storm sewer is essentially slowly varying unsteady pipe flow and methods for analyzing this type of flow are investigated. In this report the governing equations for unsteady fluid flow in pressurized storm sewers are presented. From these governing equations three numerical models are developed using various assumptions and simplifications. These flow models are applied to several example storm sewer systems under surcharge conditions. Plots of hydraulic grade and flow throughout the sewer network are presented in order to evaluate the ability of each model to accurately analyze surcharged storm sewer systems. Computer programs are developed for each of the models considered and these programs are presented and documented in the Appendix of this report.

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Funding Information

The work upon which this report is based was supported in part by funds provided by the United States Department of the Interior, Washington, D.C., as authorized by the Water Research and Development Act of 1978. Public Law 95-467.

This work was supported by a grant from the Kentucky Water Resources Research Institute under project A-084-KY and a grant from the United States Department of the Interior, Washington, D.C.