WSP02557

• File Number: 8543
• Description: Closed Basin Division
• State: CO
• Basin: Rio Grande
• Water Division: 3
• Date: 7/1/1982
• Author: USBOR
• Title: The San Luis Valley Project - Closed Basin Division - Facts and Concepts about the Project
• Water Supply Pro - Doc Type: Publication

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In addition to providing a reliable supply of water, the Project is designed to
fulfill the following objectives and responsibilities:

1. To build the Project with absolutely minimum adverse social and economic
effects,

2. Without damage to the, environment,

3. Wit~out damage to important archeological and historic sites, ~/

'4. To enhance recreational opportunities, and

5. To provide wildlife benefits.

The Project is designed to salvage water presently being lost to evaporative
processes from the Closed Basin area of the northern Valley. Thus, the primary
means of securing water without affecting historic use is for the Project to tap
into a source of water which is not being beneficially used. The Project design
calls for a network of between 150 and 180 shallow wells spread out over an area
of 130,000 acres (less than 1 well per section of land on the average). The
130,000 acres within the formal Project boundaries consist of the sump area of
the Closed Basin. This area is the lowest point in the Valley other than the
bed of the Rio Grande 'itself. Water which reaches this part of the Valley,
either on or below the surface, has quite literally no place to go but up. Most
of the water which reaches the Closed Basin sump comes from the Sangre de
Cristos on the east side of the Valley. The Project salvage well system does
not depend on the very small amount of water ,which flows through the developed
farmland to the west of the Project area. The salvage well system is designed
so that it cannot "suck the water out from below" the lands surrounding the
Project.

The law authorizing the Project (Public Law 92-514) provides further assurance
that effects to ~istoric local water use will be inconsequential. By law, the
Project wells cannot tap into the first widespread artesian aquifer. At a
depth between 90 and several hundred feet below the surface of the whole Valley
floor, layers of impermeable clay seal off an enormous reserve of water. When a
pipe (an artesian well) is inserted into the lower levels, the pressure causes
water to flow naturally to the surface. Some of the first artesian wells which
were drilled in the Valley sent geysers of water over 50 feet in the air. The
thousands of artesian wells which have been drilled since then have relieved so
much of the pressure on the artesian aquifer that many Valley artesian wells
flow less and in some cases no longer ,flow at all. Because the artesian aquifer
is of such great importance to the economy of the Valley and because a new
artesian well can affect the flow of older artesian wells miles away, the
Project is prevented by law from contributing to the problem by tapping into the
artesian aquifer (for more details concerning this question see section VI and
questions 2 and 3).

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*/ One could perhaps object to items 2 and 3. The Project is designed to
Udnimize disruption of the environment and archeological sites. Mitigation
procedures are planned for those minimal effects. The net result will be no
damage.