PUB00084

• Year: 2004
• Title: Artificial Recharge of Ground Water in Colorado -- A Statewide Assessment
• CWCB Section: Administration
• Author: Colorado Geological Survey
• Description: This study was a special assignment to the CGS from the DNR Executive Director. The tqask was to assess the underground water storage options potentially available in our state.
• Publications - Doc Type: Tech Report

Artificial Recharge of Ground Water in Colorado
A Statewide Assessment

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. Dakota and Cheyenne sandstone
. Grand Junction Basin

A progress report was prepared in 1960 addressing artificial recharge at Olds Reservoir and
Kiowa Creek (CSU, 1960).

Application of artificial recharge in Colorado blossomed in the 1980s following the drought of
1977 as farmers in the South Platte River Basin and the San Luis Valley realized that artificial
recharge could be used to restore water levels in the near-surface aquifers as well as to manage
timing of available surface-water supplies with high demands during crop growing seasons.
Recently, artificial recharge is being developed in the Denver Basin by several municipal water
districts for long-term storage. An in-depth discussion of artificial recharge projects in Colorado
is presented in Section VI.

II. Definitions of Recharge

The ultimate source of ground water is precipitation (rain, hail, or snow). Natural recharge
occurs when precipitation percolates into the ground and reaches the water table. Natural
recharge rates in Colorado are highly variable, with only 0-12 percent of precipitation
contributing to recharge of long-term ground-water storage. Enhanced recharge has historically
consisted of vegetation management, where deep-rooted, water-loving vegetation is replaced by
shallow-rooted water-conserving vegetation or bare soil. Enhanced recharge can also be
achieved by routing storm-water runoff from urban areas to designed infiltration facilities.
Induced recharge is created by the pumping of alluvial wells adjacent to streams and rivers.
Decreased water tables around the wells increase flow to the alluvial aquifer through the riverbed
and stream banks. Incidental recharge is the unintentional recharge of ground water including
return flows from septic-tank leach fields and deep percolation from irrigation. The reduction in
evapotranspiration and increased runoff resulting from urbanization (more land surface covered
by impermeable materials) may also be considered incidental recharge in circumstances where
that water flows to natural surfaces or ephemeral streams. Various types of recharge and
underground water storage are illustrated in Figure II-I.

Artificial recharge, aquifer storage and recovery, and underground water storage are terms that
are central to the topics of this study. The definitions of these terms as used in this report are:
Artificial Rechar2e (AR): Engineered or designed systems that put water on, or in, the
ground for the purpose of infiltration and subsequent migration to underlying aquifers to
augment ground-water resources. (the term "artificial" implies a mechanism other than
natural meteoric ground-water formation)

AQuifer Stora2e and Recovery (ASR): ASR is a type of artificial recharge that focuses
on the use ofinjectionlpumping well systems to inject water directly into the receiving
aquifer for future recovery at the same location.

Under2round Water Stora2e: The storage of water beneath the ground surface in large
caverns, voids, or mines in which hydraulic control can be maintained.

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