WSP11716

• File Number: 8507
• Description: Rio Grande Project
• State: CO
• Basin: Rio Grande
• Date: 7/1/1997
• Title: Water Management Study: Upper Rio Grande Basin part 1
• Water Supply Pro - Doc Type: Report/Study

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Maior Physical, Legal, and Institutional Characteristics

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Albuquerque sat atop an aquifer holding water roughly equivalent to one of
the Great Lakes. Events have proven otherwise, however, as water tables
and even the land surface have dropped dramatically in some locations.
Subsequent scientific investigation (Kernodle et al. 1995; Thorn et al. 1993)
has found that the deposits are not layers of coarse sand from which water is
easily extracted. Instead, layers of fine-grained material hold less water and
do not relinquish it easily. Geologic faults and other features interfere with
lateral movement of water. Thus, although there still is a lot of groundwater
in the Basin, it will be increasingly costly to extract.

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Some parts of the aquifer are hydrologically connected to the river and are
recharged through percolation. In some places, recharge can occur over a
large landscape, but in others it occurs in small, isolated points. Some parts
of the aquifer are hydrologically isolated from the river and experience no .
recharge.

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Since the middle 1950s, the State has required groundwater and surface
water in the Albuquerque Basin to be managed as though they were fully
connected hydrologically. Thus, one could increase groundwater pumping
only by bringing new water to the Basin or by retiring an equivalent amount
of surface-water rights. In the 1970s, the City of Albuquerque responded to
this requirement by purchasing rights to 48,200 af of water the Bureau of
Reclamation (BuRec) was importing to the Upper Rio Grande Basin from the
headwaters of the San Juan River. In recent years, the City has pumped
about 140,000 af and delivered 60,000 afback to the river through its
wastewater treatment plant. Thus, the City was believed to be depleting the
river of about 80,000 af a year and it offset this by allowing the surface water
it owns (San Juan water plus water native to the Rio Grande) to flow
through the valley and percolate into the aquifer. Until recently, it was
thought that recharge from its surface water was roughly equal to the
amount of surface water it allowed to percolate into the aquifer. The
hydrogeologic system was presumed to be in balance, and the City could have
increased groundwater use further only by retiring an equal amount of
surface-water use.

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More recently, scientific studies (Kernodle et al. 1995; Thorn et al. 1993)
indicate that only 50,000 af of the City's surface water recharges the aquifer
and, hence, the City has been pumping water out of the aquifer faster than
the recharge. Instead of being in balance, the aquifer has been drawn down,
with some of the draw down being consumed and some being delivered to the
river. The City has embarked on a program to decrease water consumption

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