Storing Water Underground Holds Promise for South Metro

By Eric Hecox

Last week I discussed the South Metro Water Supply Authority’s “all of the above” approach to solving the problems articulated in CFWE’s 2007 Citizen’s Guide to Denver Basin Groundwater. A critical part of our plan in creating a secure water future is storage. As we pursue surface water storage such as the Chatfield Reallocation Project and Reuter-Hess Reservoir, we are also pursuing the implementation of Aquifer Storage and Recovery (ASR) throughout the South Metro area.

ASR, as defined in the 2007 Citizen’s Guide, is the storage of water in a suitable aquifer through direct injection in a well when water is available and later recovery of the water from the same well when it is needed.

ASR has been successfully implemented in portions of the Denver Basin for more that 20 years. South Metro Water and several of our members are actively exploring options to broaden this practice to store renewable water during times when it is available for later use in years of drought. Some advantages of ASR compared to traditional surface storage in reservoirs include reduced infrastructure and permitting costs, lower evaporation loss and, typically, greater public acceptance.

Centennial Water and Sanitation District, serving Highlands Ranch, was one of the first providers in the state to pursue ASR, and has been successfully implementing it since 1994. They currently have 25 wells equipped for ASR and have stored more than 14,000 acre-feet, almost a year’s worth of supply for Highlands Ranch. Centennial Water continues to expand and explore ways to optimize its ASR program.

Denver Basin aquifer map

Given this success, and the fact that renewable water supplies are becoming available to the South Metro area through the WISE Project partnership, theChatfield Reallocation and other projects, South Metro entities are in a unique position to execute local and regional ASR. ASR as part of a large-scale conjunctive use plan can help change the use of the Denver Basin aquifer system from an unsustainable base supply to secure and sustainable drought supply.

Building on Centennial Water’s success, several other South Metro entities are pursuing pilot projects within their local areas to test how ASR would work with specific renewable water supplies in specific wells within their service area. East Cherry Creek Valley Water and Sanitation District (ECCV), the Town of Castle Rock, Rangeview Metropolitan District, and Pinery Water and Wastewater District are studying and pilot-testing and have plans to incrementally expand ASR within their existing well fields.

For its part, the South Metro Water Supply Authority is conducting its own pilot ASR project, using grant money from the Colorado Water Conservation Board. The pilot, expected to begin in 2016, will evaluate the viability of injecting water from the WISE Project into the Denver Basin Aquifer through an existing well and then pumping it out as needed. This information will help members better identify how ASR with WISE water might fit into long-term plans.

aquifer injectionWhether implemented individually by South Metro entities or as part of a regional ASR program, there is great potential for ASR in the Denver Basin Aquifer system. South Metro Water estimates that existing well fields may have more than 100 million gallons per day (MGD) of capacity available for ASR without dramatically impacting current well field operations.

As renewable water supplies come into the South Metro area, ASR can play a significant role in creating a secure and sustainable water supply for the region.

aquifer recoveryRead more about aquifer storage and recovery,  explore some of the advantages and disadvantages of ASR compared with conventional storage, plus find out about ASR around the globe.

South Metro Water E-News: A Secure and Sustainable Water Future

winter river in ColoradoFebruary 26, 2015

The South Metro Water Supply Authority and our 14 members are executing a plan to provide a secure and sustainable water future for the region. This effort is critical to the success of our communities now and in the future. After all, water makes the South Metro region’s incredible quality of life and growing economy possible.

It’s important that you know what we are doing to protect home values and jobs and provide communities our children and grandchildren can call home. With this in mind, we will be providing you periodic updates on the progress of this plan to help you better understand how regional water providers are working together to diversify and increase our water supply.

Two articles recently published in The Denver Post and local newspapers throughout the South Metro region and describe the plan in more detail.

We invite your input. To learn more about how you can get involved, or to request a presentation to a local civic organization, business or homeowner group, please reply to this email.

Be sure to check out our new website and share with your network. 

Eric Hecox
Executive Director, South Metro Water Supply Authority

Denver Post Op-Ed: Creating a secure water future for south metro Denver

Opinion, By Eric Hecox
Denver Post
December 22, 2015

Rueter-Hess Reservoir

Colorado took an important step in addressing the state’s long-term water challenges by completing a draft of a state water plan. The plan offers a foundation from which local and regional water entities can work as we pursue solutions that balance local needs with statewide priorities. One need only look to the suburbs south of Denver to find many of the plan’s key tenets in action and a picture of what an effective “all-of-the-above” strategy looks like.

The water challenges facing the south metro region are well known. Historically we have relied too heavily on non-renewable underground aquifers. We must transfer to a secure, sustainable supply to protect property values, jobs, our economy and our quality of life.

What’s less known is the progress we have made. In the late 1990s, aquifer declines averaged 30 feet per year. This has dropped to an average of 5 feet per year today. A decade ago, about 70 percent of our region’s water came from non-renewable sources. By 2020, that will be reduced to 45 percent. Some communities, including Highlands Ranch, are close to or have cut that number to zero.

While we still have work to do, we have made tremendous progress in short time because we followed an “all-of-the-above” approach that mirrors the one advocated by state water leaders.

The approach begins with conservation. The south Denver metro region has reduced per capita water use by more than 30 percent since 2000. A few examples of local efforts:

  • Providers serving Highlands Ranch and Castle Rock are two of only three in the state to put water customers on a water budget that tracks use by household.
  • Sterling Ranch is conducting the state’s first rainwater harvesting pilot study.
  • Inverness provides rebates for replacing turf with low water use landscaping.

Being a good steward of our limited water resources means more than conserving, however. It also means being as efficient as possible with this precious resource, which is why the state plan makes water reuse a priority. Here, too, the south metro region is leading, with all of our providers reusing their reusable water supplies or planning to:

  • Inverness Water and Sanitation and the Meridian Metropolitan District are among the earliest adopters of water reuse in Colorado. They reuse 100 percent of collected wastewater.
  • Castle Rock recently completed the Plum Creek Water Purification Facility as part of its goal of attaining a 75 percent renewable water source.

Increased water storage is another component of the statewide plan that the south metro area has put to action:

  • The recently completed Rueter-Hess Reservoir provides storage to Parker and three other South Metro Water members. When filled, the reservoir will be 50 percent larger than Cherry Creek Reservoir.
  • The expansion of Chatfield Reservoir is a collaboration among nine entities, including four South Metro Water members, to add storage to an existing reservoir.

Regional cooperation is another key tenet of the state water plan that is playing out in the south Denver suburbs. Through local and regional partnerships, we are getting more use out of existing infrastructure and supplies.

The WISE Project is a first-of-its-kind partnership with Denver Water and Aurora Water that bolsters water supplies to the south Denver suburbs while maximizing existing water assets in Denver and Aurora. Similarly, Arapahoe County Water and Wastewater Authority and East Cherry Creek Valley partnered to complete a state-of-the-art water treatment plant in 2012 and are working with several other South Metro Water members to share capacity on the ECCV Northern Pipeline.

The Colorado Water Plan provides a helpful roadmap. Born out of necessity, South Metro Water is proud to lead the way toward a secure and sustainable water future.

Eric Hecox is director of the South Metro Water Supply Authority.