To: Honorable Mayor and Members of Town Council
Through: David L. Corliss, Town Manager
From: Mark Marlowe, P.E., Director of Castle Rock Water
Roy Gallea, P.E., Engineering Manager
Josh Hansen, P.E., Project Manager Supervisor
Erin Evans, P.E., Project Manager
Title
Resolution Approving the First Amendment to Town of Castle Rock Services Agreement with Carollo Engineers, Inc. for the Escavara Odor Evaluation Project
Body
________________________________________________________________________________
Executive Summary
Staff requests Town Council approval of a First Amendment (Attachment A) to the services agreement with Carollo Engineers, Inc. (Carollo) for the Escavera Wastewater Odor Evaluation. This proposed First Amendment is a contract addition in the amount of $146,922, plus a 10% Town-Managed contingency of $14,692 for a total authorization of $161,614.
Carollo is approaching completion of the first phase of the odor evaluation project. These services included collecting and analyzing wastewater liquid and gas samples over a period of 3 days, modeling odor generation based on the sample results, and making recommendations to Castle Rock Water (CRW) for operational changes and facility upgrades. The recommendations were for changes that could be made at the Woodlands Odor Improvement Facility (OIF) and lift stations to reduce odors in the area of the Woodlands Interceptor. The work for this phase will generally be complete by October 2025. CRW has already implemented most of the recommendations from this phase of the study.
Using the outcomes of the initial phase of the evaluation, the next step of the project was identified to maximize odor elimination in this system. The additional scope includes evaluation of alternative pipeline alignments, evaluation of additional wastewater treatment options with associated cost estimates, and engineering assistance with existing treatment and pumping improvements. CRW Staff requested a proposal from Carollo for this amendment work. A scope of services and fee schedule were submitted by Carollo and are also included with Attachment A. Staff recommends approval of the First Amendment between the Town of Castle Rock and Carollo. Services are expected to begin upon execution of this Amendment and be complete by February 2026.
Budget Impact
Funding for this project will come from the 2025 budget as shown below.
|
Project |
Account Number |
|
Sewer Line Rehab |
213-4575-445.75-62 |
The following table summarizes budget impacts for previously approved agreements and the currently proposed amendment.
|
Agreement |
Contract $ |
Contingency $ |
Authorization $ |
|
Original Agreement (Approved 5/29/2025) |
157,080 |
15,708 |
172,788 |
|
Amendment 1 (under consideration) |
146,922 |
14,692 |
161,614 |
|
Amended Totals |
304,002 |
30,400 |
334,402 |
A budget transfer will be completed from Young American Rehab (213-4575-445.79-31) to Sewer Line Rehab (213-4575-445.75-62).
Staff Recommendation
Staff recommends Town Council approval of the resolution to approve the First Amendment to the Service Agreement between the Town of Castle Rock and Carollo for the Escavera Wastewater Odor Evaluation.
Proposed Motion
“I move to approve the Resolution as introduced by title.”
Alternative Motions
“I move to approve the resolution as introduced by title, with the following conditions: (list conditions).
“I move to continue this item to the Town Council meeting on _____ date to allow additional time to (list information needed).”
Attachments
Attachment A: Resolution
Exhibit 1: First Amendment