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TO: Mayor John Laesch
FROM: John Hoffmann, PE, Engineering Coordinator
DATE: March 23, 2026
SUBJECT:
A resolution authorizing the Director of Purchasing to execute a contract with Crawford, Murphy and Tilly, Aurora, IL, in the amount of $238,100 for water main flushing.
PURPOSE:
To maintain water main quality throughout the water distribution system.
BACKGROUND:
Regular maintenance of the water distribution system is necessary to keep the system working well. One component of the maintenance program is water main flushing.
The velocity of the water flowing through most water mains is usually low, therefore as time passes any solids in the water tend to settle at the bottom of the pipe. Though harmless, these solids can be stirred up when there is an increase in flow velocity from events such as main breaks or hydrant use.
The City's current water system hydraulic model was developed by Crawford, Murphy, & Tilly, Inc. (CMT) utilizing the WaterGEMS modelling software in 2005. The hydraulic model is used to analyze distribution flow, pressure, water age, fire flow, and impact to pumping capacity. Using this information, CMT designed the City's flushing program from 2012 to 2015.
Since then, the City has retained various contracts with CMT to incorporate distribution system changes that occur yearly because of water main installation or repair programs and new development projects. This includes a major model update in 2017 to reflect changes to the system's supply and storage capacities.
CMT's in-depth knowledge of the hydraulic model also makes CMT uniquely qualified to professionally service the flushing program. The model is used to determine appropriate flushing velocities needed to remove sediment from water main segments across the City, the required valve closures needed to achieve said velocities, and estimate the water demand impact of the flushing program on storage and supply capacities.
This contract, which is attached as Exhibit 1 ...
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