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TO: Mayor Richard C. Irvin
FROM: John Hoffmann, P.E., Engineering Coordinator
DATE: March 21, 2022
SUBJECT:
A resolution authorizing the Director of Purchasing to execute a contract with Crawford, Murphy and Tilly, Aurora, IL, in the amount of $105,600 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 slow, 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, which was updated as recently as last year. 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 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 three months that the flushing is ongoing, approximately 15% of the system will be flushed, those areas are shown on page 6 of the exhibit.
DISCUSSION:
The water main flushing ($105,600) will be funded with account 510-4063-511-38-68 which has a 2022 budget amount of $200,000.
IMPACT STATEMENT:
Generally, the impa...
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