Monitoring of pressure transients in a large water transmission system

Great Lakes Water Authority (GLWA)’s water transmission system services 3.8 million people from 112 communities in southeastern Michigan. The system includes 5 water treatment plants, 19 pumping stations and 816 miles of transmission main. The most water mains in Detroit were installed between 1900 and 1930 and majority of the transmission network in the suburbs of Detroit was built during 1960’s.

Despite increases in public infrastructure investments, municipal infrastructure is decaying faster than it is being renewed. For consequences of large diameter pipe failure will be high, GLWA is facing the problem of aging water infrastructure like other water utilities. To evaluate the probability of pipe failure, accurate information on loads acting on the transmission mains is critical. Pipe internal pressures, both steady‐state pressure and pressure transient, are among the key loads that needs to be estimated. GLWA operates a SCADA system to record steady‐state pressures throughout the transmission network. GLWA has developed a project of monitoring pressure transient events in the system.

Since 2017, GLWA has installed 34 Telog IoT pressure transient sensors, relevant hardware and software in the water system. Most of them are installed in its 14 large water pumping stations while some of them installed at valve pits and one of its 5 high lift pump stations. GLWA will complete pressure transient sensor installation for the remaining 4 high lift pump stations. A IoT recorder will record a pressure transient event when the pressure difference (either increasing or decreasing) reaches 15 pounds per square inch or more in a second. The pressure impulse data sampled by transient devices is wirelessly sent to Telog’s data host server. Over 30,000 pressure transient events have been recorded to date. To assess the pressure transient events, GLWA developed a Power BI application with a custom application program (API) to batch large quantity of pressure transient data from Telog’s server. The Power BI application allows GLWA to leverage pressure transient data and analytics. Since July 2020, GLWA has deployed Trimble Unity Remote Monitoring software to manage the pressure transient recorders and view the data. Trimble Unity can alarm users based on the amplitude of a pressure transient event.

GLWA has a predictive model to evaluate the conditions and forecast future rehabilitation or replacement needs of the water mains. The calculations are dependent on pipe length, diameter, material, age, break rates and life expectancy by manufacturer. The pressure transient data is being used as additional loading acting on the pipes to revise the predictive model.

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