WSP01461

• File Number: 8549.800
• Description: Rio Grande Basin-Miscellaneous Small Projects and Project Studies-Rio Grande Assessment
• State: CO
• Basin: Rio Grande
• Water Division: 3
• Date: 2/1/1981
• Author: Brandes Kier Stecher
• Title: Water Resources Reference Base for the Assessment of the Rio Grande Region
• Water Supply Pro - Doc Type: Report/Study

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large capacity wells average 1,000 to 2,000 GPM, and have been recorded as
high as 3,000 GPM. At the end of 1973, it was estimated that the Texas por-
tion of the Masilla Bolson contained 560,000 acre-feet of fresh water in
-storage and that the Hueco Bolson had approximately 10.6 million acre-feet of
storage [17,22J. Natural recharge to the bolson and alluvial aquifers is
from direct precipitation and from infiltration of flood flows discharged
by peripheral mountain streams. In addition, leakage from the Rio Grande,
from irrigation water delivery systems, and from irrigation water applica-
tions recharge the aquifers. Recently, heavy pumping has resulted in mining
of the ground water resources of the area.

Downstream from Fort Quitman to Big Bend National Park (WAU 130402),
there are several other bolson aquifers; Red Light Draw Bolson, Green River
Valley Bolson, and Presidio and Redford Bolsons. Red Light Draw Bolson is
filled with coarse grained alluvial fan deposits as much as 3,600 feet thick,
but averaging only 500 feet in thickness. Individual irrigation wells yield
1,000 to 1,500 GPM. There are approximately 600,000 acre-feet of fresh water
available of which 450,000 acre-feet are recoverable; the effective recharge
rate is 2,000 acre-feet/year. Green River Valley Bolson fill averages 750
feet in thicknesses, with a maximum of about 2,800 feet. Individual well
yields for irrigation purposes are 1,000 to 1,500 GPM. There are approxima-
tely 280,000 acre-feet of fresh water available of which only 210,000 acre-
feet are recoverable. The effective recharge rate is 1,000 acre-feet/year.
The Presidio and Redford Bolsons range from 500 to 5,000 feet in thickness.
Well yields average only 300 to 800 GPM, but are as high as 2,000 GPM.
Approximately one million acre-feet of fresh to slightly saline water is in
storage of which 75,000 acre-feet are recoverable. The effective annual
recharge rate is 7,000 acre-feet [22J.

From Big Bend National Park to the confluence of the Rio Grande with
the Pecos River, the principal aquifer is the Edwards-Trinity. It is com-
prised of fine to coarse grained sand in the lower part and limestone in the
upper part. Fracture, vugular, solution channel and caverneous porosity is
well developed in the limestone. The occurrence and yields from these aqui-
fers in the study area are variable and poorly documented; extensive use of
water in this aquifer would adversely affect surface water supplies [17J.

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