Skip to main content


Buy Article:

$17.50 plus tax (Refund Policy)

Or sign up for a free trial

Community sewer utilities use flow monitoring and hydraulic analysis to assist their engineers in making design decisions for system improvements. This information is used primarily to identify pipe (or facility) capacity or remaining available capacity for growth. In the past, such studies relied heavily on an analyst's judgment and lacked objective statistical parameters about the level of confidence in the data and the projected flows. This paper presents a case study conducted for the Bowling Green Municipal Utilities in Bowling Green, Kentucky that illustrates the typical steps that should be accomplished for completion of a successful study. The study analyzed the results from 44 days of flow monitoring at four locations along the 46-cm (18-in) interceptor downstream from the Campbell Lane Pumping Station. The immediate purpose of the study was to identify the limiting capacity of that interceptor so new pumps could be selected to upgrade that pumping station. Although this was a relatively small study, several conditions were identified that represent typical “pitfalls” for analysts evaluating flow monitoring data. Additionally, the case study illustrates a practical application of the previously proposed “Standardized Method for I/I Analysis” (Kurz, et al, 2003) That method projects the level of I/I (rainfall dependent I/I) for a design storm. It also identifies the range of values within a 95% confidence interval so that the engineer can plan for different degrees of uncertainty in future designs. This procedure is not proprietary and will be described in sufficient detail for a municipal engineer to successfully adapt it to the needs of any community.

The monitoring revealed that the limiting capacity is approximately 9,840 m3/day (2.6 mgd). This limit occurs in a reach which has an invert grade of 0.15%, which is the smallest slope that occurs along this interceptor. Slope alone indicates that this reach controls the capacity. However, the scattergraph analysis revealed additional capacity degradation under high flow conditions. This capacity is based on observed surcharge conditions and is less than what was projected theoretically. However, the pipe is deep and some surcharge to develop head pressure for peak flows was deemed acceptable.

This paper will discuss the procedures used to evaluate the reliability and quality of the flow monitoring data. All measurements were depicted on scattergraphs by plotting velocity vs. depth.

These data points were compared to “best-fit” curves representing depth and velocity from the Manning equation with various “hydraulic coefficient” values – expressed as the “square root of slope divided by the friction factor” in the Manning equation.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Data/Media
No Metrics

Document Type: Research Article

Publication date: 2004-01-01

More about this publication?
  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

    A subscription to the Proceedings of the Water Environment Federation includes access to most papers presented at the annual WEF Technical Exhibition and Conference (WEFTEC) and other conferences held since 2000. Subscription access begins 12 months after the event and is valid for 12 months from month of purchase. A subscription to the Proceedings of the Water Environment Federation is included in Water Environment Federation (WEF) membership.

    WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access. Access begins 12 months after the conference or event
  • Subscribe to this Title
  • Membership Information
  • About WEF Proceedings
  • WEFTEC Conference Information
  • Learn about the many other WEF member benefits and join today
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more