BOARD00363

• Board Meeting Date: 5/24/2004
• Description: Artificial Recharge of Ground Water in Colorado - A Statewide Assessment
• Board Meetings - Doc Type: Memo

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Artificial Recharge of Ground Water in Colorado
A Statewide Assessment

hydraulic control of injected water in carbonate cave systems presents an engineering hurdle.
Land ownership, environmental issues, and access to the cave systems are also critical
considerations.

General AR Technolo!!v Desi!!n Considerations
Each type of AR technology comes with its own set of efficiency considerations, advantages, and
disadvantages, as well as potential benefits that must be considered to make an informed system
design. Considerations include (I) project objectives, (2) hydrogeologic conditions ofthe site,
(3) source water considerations, (4) available land surface area and land-use patterns, (5) capital
cost to construct, (6) operation and maintenance (O&M) costs, and (7) general storage efficiency
issues such as evaporation losses. Table IV-l lists advantages and limitations of each
technology and provides examples of applications in Colorado.

One of the most compelling advantages of incorporating AR in a water management plan is
adaptability. AR can be installed in a phased manner that can translate to vastly reduced costs.
Design can be modified as phases progress based on experience, advances in technology, and
changes in objectives. This is in sharp contrast to many surface-water storage facilities that may
need to be constructed for full capacity at completion.

Additional benefits of using AR as part of a water supply utility include the following:
. Maximizing use of infrastructure during periods of low demand - Water treatment
and distribution systems are designed to meet peak demands. During periods of low
demand, which often correspond to periods of high supply of the natural water
resource, these infrastructure faci lities are underutilized. The infrastructure can be
utilized during periods of low demand to implement AR.

. Enhance well-field production - Implementation of AR and restoration of ground-
water levels allows wells to produce at higher rates during peak demand months. The
injection and recovery cycles in ASR wells can even increase well development for
greater well efficiency.

. System capital cost deferral - Implementation of AR produces more efficient use of
existing water system treatment and conveyance capacity throughout the year and life
of the facility, which means that expansion of water facilities can be deferred and
downsized with substantial cost savings.

. Maintain distribution system pressure - Recovery of stored water in conjunction with
small elevated or ground storage tanks can alleviate seasonal low pressure issues
during peak demand months.

. Commercial/industrial temperature control- Seasonal source water temperature
variability can be mitigated by recovering and blending AR water to meet process
temperature control requirements such as fish hatcheries or industrial cooling.

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