In 2007, Highlands Ranch Water achieved a significant milestone in its history with the completion of the South Platte Reservoir. The project transformed a former gravel mine into a critical component of the community’s long-term water supply strategy.

Located north of Chatfield Reservoir in Littleton, the 6,480-acre-foot reservoir represented more than a construction project. It was the culmination of nearly two decades of planning and investment designed to strengthen water reliability for Highlands Ranch residents for many years to come.

At the time, concerns about declining groundwater supplies were making headlines across Colorado. Highlands Ranch Water, then known as Centennial Water & Sanitation District, had a different vision, increase reliance on renewable surface water supplies from the South Platte River while preserving deep groundwater aquifers as a backup resource.

An article published in the Denver Post on Sept. 21, 2007, quoted Joe Blake, former senior vice president of Mission Viejo Company, the developer of Highlands Ranch, as saying, "We always said you can never have enough water. Our goal was always to seek a greater proportion of surface water compared to groundwater."

South Platte Reservoir became a key piece of Highlands Ranch Water's conjunctive use system, which combines renewable surface water with groundwater resources to create a resilient and flexible water supply. In fact, 2007 marked a year when 100% of the community's water supply came from surface water sources.

Planning for South Platte Reservoir began in the early 1990s when district leadership identified a growing need for additional storage. At the time, the Highlands Ranch Water had access to approximately 4,000 acre-feet of storage in McLellan Reservoir. Studies showed that expanding storage capacity at South Platte Reservoir would allow the district to more effectively capture, store and manage water from its South Platte River water rights.

The project required extensive collaboration among multiple organizations, including the City of Littleton, South Suburban Parks and Recreation, and local ditch companies. Together, they created a facility that not only strengthened the region's water infrastructure but also complemented the surrounding community and recreational amenities.

Today, South Platte Reservoir remains unique within Highlands Ranch Water's portfolio as the only reservoir owned outright by the district. It continues to play a vital role in storing renewable surface water supplies that serve Highlands Ranch customers.

As we celebrate 45 years of service, South Platte Reservoir stands as a testament to the vision of community leaders, engineers and water professionals who understood that planning for the future means investing long before the need becomes urgent. Their foresight helped ensure that Highlands Ranch would have a reliable, sustainable water supply as the community grew and continues to support residents today.