Stevens, Patrick

Patrick L. Stevens P.E. has a B.S. in Aeronautical Engineering and an M.S. in Environmental Engineering, both from Purdue University. He has worked in the environmental field since 1970 and has published over 60 technical papers and articles covering CSOt and I/I flow metering techniques. He has worked as a regulator with the Indiana State Board of Health, the Indianapolis DPW and is now V. P. Engineering for ADS Environmental Services, a firm specializing in measuring sewer performance. He helped develop Sliicer.com, is a founding member of the American Society of Sewer Sociologists and is a 2019 WEF Fellow

Titles from this speaker

The Big Debate: Can Depth-only Devices Used for I/I Work

Abstract

Depth has been used to gauge flow rate for thousands of years with several improvements along the way. A significant improvement was offered by Robert Manning in the late 1800’s as a simple equation using depth to calculate velocity (and flow) in an open channel. The Manning Equation is still used today in most open channel hydraulic models, but the advent of the Infiltration/Inflow discipline in the United States in the 1970’s revealed the serious shortcomings of its application to flow measurement in sanitary sewers. There are too many unusual hydraulic conditions in sanitary sewers that make the Manning Equation invalid as a method for measuring flow. Today however, some manufacturers of depth-only devices are promoting them as an inexpensive way of ‘chasing I/I’ and suggesting that they can be ‘calibrated’ by knowing the house count or Equivalent Dwelling Units upstream. These developments have spawned the debate as to whether the devices can be used in I/I work. Experienced I/I analysts say ‘No’ while first time analysts don’t understand why they cannot. As Yogi Berra said, “In Theory, Theory and Practice are the same, in Practice they are not”. This paper includes four case studies looking at the practice of using depth-only devices for I/I measurement. The author of this paper approached the use of depth-only technology for I/I work with optimism. ADS was looking for a new application for its unique and successful ECHO depth-only product. This paper documents the learning curve followed as several attempts were made to deploy ECHO devices in I/I applications. In the end it is believed that we have re-learned and re-documented why the sewer flow measuring industry abandoned the depth-only Manning equation in sanitary sewers 40 years ago.

SpeakerStevens, Patrick

Presentation time

13:30:00

14:00:00

Session time

11:30:00

12:30:00

SessionInflow/Infiltration: Fighting the I/I

Session number7D

TopicCollection Systems, Watershed Management, Water Quality, and Groundwater

Author(s)

P. Stevens