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
Title
Resolution Approving the First Amendment to the Rueter-Hess Drought Water Supply Pilot Plan Intergovernmental Agreement between the Town of Castle Rock Water Enterprise and Denver Water, Parker Water and Sanitation District, and East Cherry Creek Valley Water and Sanitation District [Located in northwest and northeast Douglas County]
Body
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Executive Summary
The purpose of this memorandum is to request Town Council approval of an Amendment to an Intergovernmental Agreement (IGA) between Castle Rock Water (CRW), Denver Water, Parker Water and Sanitation District (PWSD) and East Cherry Creek Valley Water and Sanitation District for the Rueter-Hess Drought Water Supply Pilot Plan. The resolution approving the amendment to the agreement is provided in Attachment A and the Amendment to the Intergovernmental Agreement (IGA) is Exhibit 1 to the Resolution.
The aforementioned parties desire to extend the Pilot Plan for four additional years, expiring on December 31, 2028. This pilot project involves storage of water in Rueter-Hess Reservoir (RHR) under the current terms of the RHR 404 permit and helps CRW to store its currently permitted fully-reusable return flows, which are captured and stored in Chatfield Reservoir, into RHR using existing infrastructure.
The way the pilot operates is that Denver Water transfers “Pilot Water” into the WISE System using the existing Conduit 111 / WISE Pipeline interconnection. Pilot Water is then pumped through WISE infrastructure to PWSD’s Rueter-Hess Water Purification Facility (RHWPF) where it combines with other water and enters PWSD’s potable water distribution system. When PWSD uses the Pilot Water in the manner described above, PWSD has a reduced need to withdraw water supplies stored in RHR. Therefore, PWSD will book over water stored in a PWSD RHR storage account into a new PWSD subaccount titled “Pilot Plan Storage Account.”
On August 21, 2024, Denver Water and CRW coordinated to perform a swap of 390 acre-feet (AF) of water. This block of water was booked from Castle Rock’s Chatfield Reservoir storage account to a Denver Water Chatfield Reservoir storage account. Simultaneously, Denver Water booked over 390 AF of RHR Pilot Plan Storage Account water to the CRW RHR storage account.
The original IGA contemplated up to 1,000 AF of water (total) being transferred in the manner described above.
The benefit of this agreement to CRW is that it gives an opportunity to add additional supplies into RHR, where through other agreements with PWSD, we can treat and deliver additional potable water to our customers. PWSD will realize higher water levels in RHR and Denver Water will be able investigate potential future options for storing water in RHR. The pilot project will also use some of ECCV’s pumping and piping infrastructure to move water to PWSD’s system, and because the primary benefit is for CRW, the Town will pay energy recovery costs and administrative fees to ECCV during the pilot project. In 2024, CRW paid $15,581 to ECCV.
Budget Impact
The total cost of the Pilot Project will depend on the total quantity of water transferred and the time of year (ECCV’s summer pumping rates are higher than the winter pumping rates). Assuming summer pumping and $400 monthly administrative costs during the months when water is pumped, we estimate the cost of the Pilot Project to be approximately $80,000 to transfer the full 1,000 AF of water. Payments for this Pilot Project will be made from the CIP operation and maintenance account 211-4375-443.40-90 <Project Code WR RHR>. CRW paid ECCV $15,581 in 2024 for their pumping associated with this project.
Staff Recommendation
Staff and CRW Commission recommend that Town Council approve the first amendment to the Water Service IGA.
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
Staff Report
Attachment A: Resolution
Exhibit 1: Amendment to the IGA