To: Honorable Mayor and Members of Town Council
Through: David L. Corliss, Town Manager
From: Mark Marlowe, P.E. Director of Castle Rock Water
Matt Benak, P.E., Water Resources Manager
Lauren Moore, Water Resources Program Analyst
Title
Resolution Authorizing a Change Order to the Construction Contract Between the Town of Castle Rock and Colorado Pump Service & Supply CO., for the Denver Basin Well Rehabilitation and Pumping Equipment Replacement Project, and the Abandonment of Inactive Wells
Body
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Executive Summary
The purpose of this memo is to seek Town Council approval for a resolution (see Attachment A) approving a Construction Contract Change Order No. 4 (see Exhibit 1) with Colorado Pump Service & Supply Co. for the 2021 Denver Basin Wells Rehabilitation, Pumping Equipment Replacement, and Well Abandonment Project Attachment B provides the memo from the original contract approval by Council. Upon initial rehab of Well CR-72R, a large mass of hardened material was discovered. Change Order 1 was used to purchase materials and treat for/remove this material from the well. As the material has since been successfully removed, Staff is recommending an additional cleaning to ensure all material has been removed from the well. Change Order No. 4 will cover the additional rehab and cleaning for Well CR-72R to bring this well back online in time for peak summer demands. The total cost for the change order is $42,796.00, with a request for $35,771.60 of additional authorization outside of the original construction contract and contingency. Staff has reviewed the pricing and finds it to be line with typical costs for this rehab cleaning. Work will be incorporated into the current project and will extend the schedule by 94 days, which extends project completion to December 2021, although completion is anticipated by the end of July.
History of Past Town Council, Boards & Commissions, or Other Discussions
Castle Rock Water Commission was informed of the project at their February 24, 2021 meeting.
March 2, 2021, Town Council unanimously approved the Construction Contract with Colorado Pump for the 2021 Denver Basin Wells Rehabilitation, Pumping Equipment Replacement, and Well Abandonment Project.
Notification and Outreach Efforts
Postcard mailers were sent to nearby homes describing the project details such as location, dates, and work hours. Additionally, the project is listed on the Castle Rock Water website.
Discussion
As part of the 2021 Denver Basin Rehab Project, Colorado Pump, Service & Supply was awarded four Denver Basin Wells (CR-72R, CR-73R, CR-86, & CR-117) for rehabilitation and equipment replacement as well as one well for abandonment (CR-31). During the rehab process of pre-videoing, a large buildup of material was identified at the beginning screen section of Well 72R at approximately 688 feet below ground surface. Cleaning proceeded as scheduled, with extra attention spent on this built up section. The post-video showed a clearer picture of the built up hardened material. Colorado Pump was able to carefully knock some sections of it off (enough to fill 5-gallon bucket) and bail it out. The hard rock material is suspected to be some sort of calcium buildup leaching from the aquifer. Change Order 1 was used to purchase Special Acid and circulate it around the hardened material in order to dissolve it. After 12 days of acid treatment, the material was successfully removed. Staff recommends completing an additional cleaning to ensure that all the acid and materials have been removed from the well before installing equipment and bringing this well back online.
Budget Impact
Funding for the project will come from Accounts Repair and Maintenance - Wells 210-4250-442.40-37. The following table shows the breakdown of funding. Town staff will use the funds to complete rehabilitation and equipment replacement for this project. Colorado Pump Service & Supply Co.’s proposed fee for Change Order No. 4 is $42,796.00, of which Staff requests an additional $35,771.50 be authorized for a total authorization of $621,514.08.
Staff Recommendation
Staff recommends Town Council approval of a Resolution approving Construction Contract Change Order No. 4 (see Exhibit 1) with Colorado Pump Service & Supply Co. for the 2021 Denver Basin Wells Rehabilitation, Pumping Equipment Replacement, and Well Abandonment Project and authorizing an additional $35,771.50 for payment of that change order.
Proposed Motion
“I move to approve the Resolution as introduced by title.”
Attachments
Attachment A: Resolution
Exhibit 1: Construction Contract Change Order No. 4
Attachment B: 2021 Denver Basin Rehab Memo (Colorado Pump)