Tag Archives: Denver Basin

Opinion: Bill Promotes Opportunities for Implementing More Aquifer Recharge and Recovery Projects in Colorado

By Ralf Topper

HB 17-1076 is currently making its way through the legislative process having passed the House and the Senate.  This legislation, concerning rulemaking for artificial recharge of nontributary aquifers, opens the door for opportunities to implement aquifer storage and recovery programs in nontributary aquifers outside of the Denver Basin.  Nontributary groundwater, as defined in Colorado Revised Statute 37-90-103 (10.5), is groundwater whose connection to any surface stream is so insignificant that it is considered isolated from the surface water for water rights administration purposes.

HB 17-1076 is a first step in creating some administrative certainty and legal framework for districts in other parts of the state to consider implementing aquifer recharge and recovery projects to meet their water management objectives, and should be endorsed by the water community.  The bill’s use of the term “artificial recharge” is unfortunate, as the use of that term is dated in scientific and engineering literature though still used in reference to older studies and legislation herein.  Aquifer storage and recovery (ASR) is designed to introduce water into and store water in underlying aquifers with a future extraction component when additional supplies are needed.  ASR is typically implemented through wells.

Increasing storage is an integral theme of Colorado’s Water Plan, published in 2015, and aquifer storage and recovery opportunities dominate the plan’s discussion regarding groundwater.  Subsurface water storage in aquifers can significantly reduce the financial, permitting, environmental, security, and socioeconomic hurdles associated with construction of new surface-water reservoirs.

In 1995, the State Engineer promulgated rules and regulations for the permitting and use of waters artificially recharged into the Denver Basin aquifers.  The Denver Basin is the only aquifer system in Colorado with specific rules regulating the recharge and extraction of non-native water for storage purposes and as such is currently the only area in Colorado with active ASR projects.  The promulgation of those rules has provided both opportunity and certainty for water districts to implement subsurface water storage projects.

  • Centennial Water and Sanitation District started ASR operations in 1994 and currently has 25 wells permitted and equipped to inject water into Denver, Arapahoe, and Laramie-Fox Hills aquifers. Through 2014, they have stored over 14,000 acre-feet of potable water.
  • Others districts that have implemented ASR operations include Consolidated Mutual, Colorado Springs Utilities, and Castle Pines Metropolitan.
  • East Cherry Creek is currently in the testing phase and implementation plans are moving forward in Castle Rock, Meridian, Rangeview, Inverness, and Cottonwood.
  • Denver Water has initiated a significant evaluation program and South Metro Water Supply Authority considers ASR a critical component of utilizing water supplies from the WISE partnership.

Subsurface water storage opportunities in bedrock aquifers in other portions of Colorado have been well documented.  In 2003, the Colorado Geological Survey produced a statewide assessment of subsurface storage potential opportunities for then-director of Colorado’s Department of Natural Resources Greg Walcher.  Published as Environmental Geology Series 13, that study identified 29 priority regional consolidated bedrock aquifers with potential storage capacities from 10’s of thousands to over a million acre-feet.  In 2006, Senate Bill 06-193 directed the Colorado Water Conservation Board to conduct an underground water storage study in the South Platte and Arkansas River basins.  That study  identified a number of areas for potential underground water storage in both basins with available storage capacities of tens to hundreds of thousands of acre-feet in most areas.

 Ralf Topper has recently retired with 16 years of service as the senior hydrogeologist in both the Colorado Division of Water Resources and the Colorado Geological Survey.  He has earned advanced degrees in Geology (BS, MS) and Hydrogeology (MS) from CU-Boulder and Colorado School of Mines, and has over 35 years of professional geoscience experience in both the private and public sectors.  He is a Certified Professional Geologist, a Geological Society of America Fellow, and an active member of both national and state groundwater societies.  Ralf has authored numerous papers and publications on Colorado’s groundwater resources including the award-winning Ground Water Atlas of Colorado.

 

 

 

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Storing Water Underground Holds Promise for South Metro

Well ASR

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

The Denver Basin aquifer system includes the Dawson, Denver, Arapahoe and Laramie Fox-Hills aquifers; the water they contain is considered a nonrenewable resource due to the slow rate of natural replenishment.

Given this success, and the fact that renewable water supplies are becoming available to the South Metro area through the WISE Project partnership, the Chatfield 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.

Eric_Hecox_1Eric Hecox is the director of the South Metro Water Supply Authority, a regional water authority comprised of 14 water provider members that collectively serve more than 300,000 residents as well as businesses in the south metro Denver area. South Metro Water’s membership spans much of Douglas County and parts of Arapahoe County, including Castle Rock, Highlands Ranch, Parker and Castle Pines. Eric also serves on the board for the Colorado Foundation for Water Education.

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Filed under groundwater, Water Supply