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 Program Manager
Title
Resolution Approving an Intergovernmental Agreement Between Denver Southeast Suburban Water & Sanitation District d/b/a Pinery Water & Wastewater District and the Town of Castle Rock for Water Delivery [Water system interconnection near Mentha Drive and Carefree Trail in the Cobblestone Ranch subdivision]
Body
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Executive Summary
Castle Rock Water (CRW) staff recommends that the Town enter into an Intergovernmental Agreement (IGA) with Denver Southeast Suburban Water & Sanitation District d/b/a Pinery Water & Wastewater District (“Pinery”) (Attachment A, Exhibit 1) for delivery of CRW’s portion of its water owned in the Cherry Creek Project Water Authority (CCPWA) and potentially other renewable water from the other CCPWA members as it may be available (up to one million gallons per day and at least 250 acre-feet per year). Potable water would be delivered from Pinery through the Pinery-Castle Rock interconnect located in the Cobblestone Ranch area of Castle Rock (see Attachment B). First delivery of this water could be later in 2022, depending on the results of a water quality study that is occurring now. It is possible that certain water quality parameters in the water from Pinery may need to be adjusted to ensure compatibility with CRW’s current supplies.
The advantage of this IGA is that it gives CRW the ability to receive additional renewable water on a consistent basis for a reasonable cost (either $1.20 or $1.92 per 1,000 gallons delivered, depending on the volume). There is the chance that additional costs may accrue for treatment of aesthetic water quality parameters (e.g. hardness) to ensure optimal compatibility with our existing water supplies if determined necessary by the ongoing study. Without this IGA, CRW would have to divert the water from Cherry Creek, store the water in Rueter-Hess Reservoir (RHR) and then subsequently release the water, treat it through Parker Water and Sanitation District (PWSD), and have the water delivered through the WISE local infrastructure into Castle Rock’s distribution system. These extra steps would increase the cost of delivery by 2 to 3 times even if some minimal treatment is needed for water directly from the Pinery system.
History of Past Town Council, Boards & Commissions, or Other Discussions
Castle Rock Water Commission was informed of the project at their March 23, 2022 meeting and recommended that Town Council approve the IGA.
Discussion
In February 2021, CRW became part of the CCPWA, along with the Pinery, Inverness Water and Sanitation District and Cottonwood Water and Sanitation District. CRW is particularly interested in the renewable water that can be delivered as part of the CCPWA. On average, Castle Rock would be able to access 250 acre-feet (AF) of renewable water per year. The IGA presented here would have the Pinery treat and deliver approximately 250,000 gallons per day of potable water through the water system interconnect we share in the Cobblestone Ranch area. This water would be treated by the Pinery and would act as a new renewable supply for the Town. In average years, the project would yield 250 AF of renewable water as CRW’s portion. In drier years, CRW would still receive 250 AF, but the project would use some non-renewable groundwater to supplement CRW’s portion. In wet years, CRW could potentially take more water through the interconnect or deliver renewable water to Rueter-Hess Reservoir for storage. Pinery will bill CRW $1.20 per thousand gallons (kgal) for this service for deliveries up to 250,000 gallons per day (gpd). For deliveries between 250,000 and 1,000,000 gpd the rate increases to $1.92/kgal.
Currently, Castle Rock Water is contracted with Burns & McDonnell Engineering (BMcD) to complete the Pinery Connection Evaluation and pH Adjustment Basis of Design Report (BDR). The scope of services includes evaluating water quality for aesthetic properties from the Pinery’s potable water distribution system and the possible need for water treatment prior to conveyance of this water to CRW’s potable water distribution system. Treatment for this water would be only to address aesthetic differences between CRW’s existing supplies and the Pinery water supply and would not be necessary to meet primary drinking water standards. This means that the water would be available immediately in an emergency regardless of the outcome of the ongoing study. If treatment is deemed beneficial, it is anticipated that it would occur at or near the interconnect. Preliminary costs for treatment are estimated to be $500,000. Even with these costs, this approach will be more cost effective than the other option which would be to take the water to RHR, treat the water at the PWSD treatment plant, and then deliver the water through the WISE infrastructure.
Budget Impact
Funding for the water delivery will come from the following account: Water Resources - Engineering Division - Other Professional Services 211-4340-443.30-70 ($4,080,000 budgeted in 2022). Project Code <WRPINW> will be used to identify the costs associated with the water we receive through this IGA.
Staff Recommendation
Staff recommends Town Council approval of this IGA with the Pinery for water delivery.
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: Intergovernmental Agreement
Attachment B: Location Map