Water storage is essential in our climate. Years ago, little could be done to capture the abundance of water that comes in a rush when the snow melts in the spring and during the monsoons of summer. Now we can capture water and store it in places that make sense for delivery to users, including municipalities, agriculture and residents. Reservoirs dot the arid landscape, holding the water we need for efficient water planning.

Rueter-Hess Reservoir

Parker Water and Sanitation District’s (PWSD) 30-year-old Rueter Hess project is nearly complete. On schedule or even a little ahead of schedule, the 72,000 acre-foot reservoir’s current timeline calls for it to be finished in 2012. Rueter-Hess will serve the Parker Water and Sanitation District area, as well as Douglas County communities, including Castle Rock, Castle Pines North and Stonegate, through partnership agreements.

Originally permitted in 2004, Parker Water and Sanitation District received funding of $104 million to build a 16,400-acre foot reservoir. Shortly after starting construction, the reservoir was enlarged to 72,000 acre-feet to accommodate the needs of Castle Rock, Castle Pines North and Stonegate Metropolitan District.

Parker Water will realize the benefit of having an additional approximate 45,000 surplus acre-feet of storage, which they can use for sale to other water suppliers or as carry-over storage of floodwater for future use. Every drop of the water PWSD stores has to be pumped in, so the district will begin that process in 2012.

Chatfield Reservoir’s Water Reallocation

Chatfield State Park attracts 1.5 million visitors a year and collects more than $2 million in revenue (in 2007). It is owned and operated by the U.S. Army Corps of Engineers.

As with other valuable water infrastructure assets, SMWSA must put them to their best use, helping to accommodate the growth of the Denver metro area. According to the Corps of Engineers, Chatfield can hold an additional 20,600 acre-feet of water storage without limiting its usefulness as a flood-control structure. This additional storage space could be used by water providers, farmers and environmental organizations to meet the diverse needs of Colorado’s growing population.

Downstream and upstream water providers are interested in the additional storage space in Chatfield, if approved. The proposed action would increase the storage space by 20,600-acre feet. If the reallocation is approved, the benefits include:

• 8,500-acre feet of new water supplies for municipal and agricultural users
  
  
• Reduce dependency on non-renewable groundwater
  
  
• Environmental benefits
  
  
• Facilitates the reuse of water
  
  
• Uses an existing reservoir

The project’s estimate could be about $128 million, or $6,000 per acre-foot.

Centennial Creates South Platte Reservoir

Centennial Water & Sanitation District properly planned for future water use for its 90,000 Highlands Ranch customers when it bought a gravel pit from Kiewit Western Company and turned it into a reservoir. It opened in 2007.

In 2009, the South Platte Reservoir was filled, in part due to wet conditions, but also due to smart planning by the Centennial Water Sanitation District. The 6,400 acre-feet capacity reservoir is a raw storage site, storing water from Centennial’s water rights on the South Platte River. This $25 million reservoir is the newest facility in Centennial Water’s conjunctive-use system, which relies predominantly on surface water, but combines the use of both surface and ground water supplies.

Substantial Dollars for Aquifer Recharge Pilot Study and Aquifer Storage and Recovery (ASR)

Water doesn’t have to be stored in only reservoirs. It can be stored in existing water wells. This is accomplished by injecting water in to an aquifer through wells or by surface spreading and infiltration and then pumping it out when needed.

In 2009, SMWSA received a $425K grant from the State of Colorado’s Water Supply Reserve Account (WSRA) for an Aquifer Recharge Pilot Study. This was the second phase of SMWSA’s study to determine the viability of implementing an Aquifer Storage and Recovery (ASR) program in the south-metro area, a possible means to address anticipated water shortages in south-metro Denver within the next 20 years.

Essentially, with ASR, the aquifer functions as a water bank. Deposits are made in times of surplus, and withdrawals occur when available water falls short of demand.

At the September 2010 meeting of the Colorado Water Conservation Board (CWCB), SMWSA was awarded an additional $125,000 from the State of Colorado’s Water Supply Reserve Account (WSRA) for its Aquifer Recharge Pilot Study. In January 2010, South Metro applied for a total of $550,000 and was granted a total of $425,000 for its ASR Pilot Study. The additional funding allows South Metro to fully implement its original pilot study.

The Regional Aquifer Storage and Recovery Pilot Study is moving into Phase Two. During the first phase of the study, well pumping data from SMWSA's members was used to form a greater understanding of the Denver basin aquifers. Based on the results of the study, two wells will be identified for retrofitting to ASR.

Centennial Water and Sanitation District (a member of SMWSA) has utilized ASR for over a decade and continues to be an innovator in the industry. SMWSA's objectives for the second phase of the study include:

• Identifying a source of renewable water to be used in a full-scale ASR program.
  
  
• Identifying a well that may be suitable for retrofitting to an ASR well and undertake the necessary evaluations, including engineering conceptual-level design for retrofit, and geochemical analyses on the well to identify infrastructure and pre-treatment requirements.
  
  
• Undertaking the design and construction needed to retrofit the well for ASR pilot testing and associated pretreatment.
  
  
• Conducting pilot-scale ASR testing and evaluating the feasibility of implementing long-term ASR operations.
  
  
• Providing recommendations for full-scale implementation of ASR in the south-metro area, including water pre-treatment needs, well preparation and retrofitting and O&M.
  
  
• Identifying existing ASR wells from which additional information can be gathered.