WSP03310 - Laserfiche WebLink

Home Browse Search

.";19' ~ ~,;,:.:,. -:::s.: To date, the primary interest in ground water in the Upper Basin has focused on the Piceance Creek structural basin, which lies in the midst of western Colorado's richest oil shale reserves. It is estimated that this aquifer contains 2.5 to 25 maf of water. However, it is prob- able that only part of this water could be recovered, either because of 1',::- economic limitations or because of close hydrologic connections with eo surface water supplies. Well yields from this formation vary' according ~ to surface location and well depth, with production ranging from 100 o to I,OOO gpm. The quality of the water in the Piceance Creek structural basin is fairly well known. The hydrologic system consists generally of an upper aquifer, above the confining Mahogany Zone, and a lower aquifer below the Mahogany Zone. Most water in the upper aquifer contains less than 2,000 mg/1 of dissolved solids; the water in the lower aquifer con- tains as much as 30,000 mg/l of dissolved solids in the northern part of the basin, as well as undesir- able quantities of flouride and boron throughout the basin. Various wells and test holes show that methane and hydrogen sulphide gases exist in same places. {8~) Elsewhere in the Upper Basin, the most promising aquifers for future development are the Laney and Tipton Shale Members of the Green River Formation in the Upper Green River Basin, Wyoming; aquifers in the Sierra Madre uplift in Wyoming (the area of the Little Snake River Basin, which is a tributary to the Yampa River); and various sandstone formations in the San Juan River Basin, New Mexico, and Arizona. In terms of water quality sedimentary rocks in the Upper Basin, such as shales, limestones, siltstones, and sandstones, annually yield water ranging from under I,OOO parts per million (ppm) to more than 35,000 ppm dissolved solids. Deeper ground water generally has a higher dissolved solids content than water in shallower aquifers because it has been in contact with saline formations longer. Fresh water usually occurs in shallow aquifers where the land sur- face is above 7,000 feet in altitude, or in permeable sandstones such as the Navajo and Dakota formations. Alluvial aquifers generally yield the best quality water, but some alluvial ground water may be highly saline as a result of hydrologic interconnections with saline rocks. In many cases, fresh water is separated from saline formations by relative- ly impermeable rock structures such as the Mahogany Zone in the Piceance Creek structural basin. ;r;;,~~ .'.;".' xxiii