Dominion Water and Sanitation details renewable-supply portfolio, pipeline and reuse projects

Andrea Cole, general manager of Dominion Water and Sanitation District, presented the district's current supplies, infrastructure projects and near-term timelines at the Douglas County Water Commission meeting on March 24.

"We're here to provide clean, reliable, and sustainable water supplies to our, to the residents of Northwest Douglas County," Cole said, and described Dominion as a wholesale water and wastewater provider formed in February 2004. She summarized the district's current and planned water portfolio, treatment and conveyance projects, and regional reuse objectives.

Cole said Dominion currently relies on two Aurora contracts (about 480 acre-feet committed through Aurora's Rampart system and the Moore Water Treatment Plant) and is the largest WISE subscriber at 1,325 acre-feet. To firm interruptible WISE or junior South Platte supplies, Dominion has contracting and groundwater options: a 700 acre-foot firming arrangement with Castle Rock and 625 acre-feet planned from Cherokee Ranch groundwater (the Cherokee well was drilled to obtain aquifer characteristics and is not yet equipped for production).

Key infrastructure and project details Cole provided:

- Eastern Regional Pipeline: an 11-mile, 30-inch pipeline with modeled capacity around 13 million gallons per day. The line connects Dominion into the WISE delivery network and includes pre-located turnout points for future connections. Disinfection of the pipeline began in March and staff expect first water deliveries in May.

- Chatfield Basin Water Reclamation Facility (regional wastewater plant): Dominion received $20 million in ARPA funds to help build a regional membrane-bioreactor plant with an estimated total project cost of $34 million. The plant is planned as a 0.9 MGD facility; construction work and abatement of asbestos/lead paint on the old Roxborough site are underway with anticipated operation in January 2028.

- South Platte diversion, pump station and pipeline: Dominion completed a feasibility study and is working through permitting with the U.S. Army Corps of Engineers and other agencies. The Corps-related permits (404/408) and other regulatory approvals are required; Cole said the project is targeted for construction completion by 2029 with an estimated cost of $26 million and that the district had secured a CWCB grant of $866,000 to reach 60% design.

- Reuse and return flows: Dominion projects reusable return flows will be a significant portion of firm renewable supplies at buildout. The district also holds 500 acre-feet of storage in Chatfield Reservoir and expects to capture return flows from the new wastewater plant for local reuse.

- Rainwater harvesting pilot: Dominion and partners are advancing a pilot regional rainwater-harvesting project planned for Prospect Park in Sterling Ranch; Cole said Dominion is the first pilot in the state.

Cole also described operational and demand-management practices at Sterling Ranch that Dominion requires in its rules and regulations: indoor/outdoor dual meters, water budgets with tiered rate structures, and landscaping standards developed with botanic-garden partnerships. She said Sterling Ranch's indoor use target is about 0.13 acre-feet per single-family equivalent (0.2 acre-feet total per SFE including landscaping).

Commissioners asked technical and legal questions: a commissioner asked whether the Cherokee groundwater entitlements were deeded; Cole said, "It's deeded and decreed. ... they are owned fully by Dominion and are adjudicated." Commissioners also queried permitting risks for the South Platte diversion and minimum streamflow requirements tied to Denver Water and prior easements; Cole identified permitting with the Corps as her primary concern for project timing.

Cole listed ongoing construction and design work: the Filing 7 lift station (under construction), operation and commissioning of the Eastern Regional Pipeline, Chatfield facility progressive design-build with PCL and Stantec, and feasibility studies for the diversion and regional groundwater solutions. She said Dominion is piloting PFAS treatment on the wastewater side and is evaluating treatment approaches for Cherokee groundwater.

No formal action or vote related to Dominion's projects occurred at the meeting; the presentation served as an informational briefing and commissioners were invited to ask follow-up questions and to schedule further briefings as needed.