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TO: Mayor Richard C. Irvin
FROM: John Hoffmann, P.E., Engineering Coordinator
DATE: March 11, 2024
SUBJECT:
A resolution authorizing the Director of Purchasing to execute a contract with Crawford, Murphy and Tilly, Aurora, IL, in the amount of $210,600 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.
Crawford Murphy and Tilly (CMT) was selected to update and maintain a computer model of the City's distribution system. The model is utilized for various purposes including identification of the necessary valve closures to produce the flow rates required to remove sediment from the mains. Due to their knowledge of the computer model, CMT is uniquely qualified to provide this professional service as well as direction to city employees during the flushing operation.
This contract, which is attached as Exhibit 1 - CMT Contract, will provide for the services of one staff member full-time and second person part time from CMT to direct the program. The remaining 4-6 team members required each day will come from the Water and Sewer Maintenance and Engineering Divisions. It is estimated that during the four months that the flushing is ongoing, approximately 20% of the system will be flushed, those areas are shown on pages 7 and 8 of the exhibit.
A separate $35,000 task has been identified within this contract for modifying the water model relating to the flushing program and to update the water model on an annual basis fo...
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