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B. W. Thomsen

Publications and source records attributed to B. W. Thomsen.

5 recordsLinked to original sources
USGS1978

Hydrologic data for the Copper Basin area, a potential mining area in Yavapai County, Arizona

Large low-grade ore bodies have been discovered in Copper Basin, and a large copper-mining operation is anticipated in the near future. Hydrologic data are being collected to provide the data base necessary to determine the effects of a potential mining operation on the water resources of the area. The area of potential depletion or contamination of water supplies is the 50-square-mile alluvial slope downgradient from Copper Basin. In the Copper Basin area the streams generally are dry, except for the perennial flow in a 3-mile-long reach of Kirkland Creek, where the base flow ranges from about 1 to 3 cubic feet per second. The water in the alluvium, which is more than 1,000 feet thick in places, generally is under unconfined conditions. The direction of ground-water movement is generally southwesterly toward Skull Valley Wash and Kirkland Creek. The depth to water in wells ranges from less than 10 to 675 feet below the land surface. Near the center of the area, test wells penetrate a clay confining bed at the base of the alluvium and an underlying sequence of volcanic rocks, which is more than 1,000 feet thick and contains water under confined conditions. Pump tests indicate that the confining bed forms a barrier between the water in the alluvium and the water in the volcanic rocks and that, initially, pumping from the volcanic rocks would not affect the water level in the alluvium. The areal extent of the volcanic sequence is not known.

Arizona↗
USGS1966

Water resources of Fort Huachuca Military Reservation, southeastern Arizona

The Fort Huachuca Military Reservation, on the northeast flank of the Huachuca Mountains, is in the southern part of the San Pedro River drainage in the Basin and Range physiographic province in Arizona. The main sources of water available in the reservation area are ground water stored in two unconsolidated sedimentary deposits filling the San Pedro basin, and spring flow in Garden ·and Huachuca Canyons in the Huachuca Mountains. The unconsolidated deposits are divided into the upper and lower units of basin flu. These units yield the major part of the fort's water supply, and pumping from them has caused the water level in the Fort Huachuca well field to decline 3 feet per year. All the upper unit and 40 feet of the 220-foot-thick lower unit have seen dewatered in post wells 1 and 2. In Garden Canyon, spring flow is derived from solution channels and fractures in carbonate rocks; and in Huachuca Canyon, from fractures in mudstone, sandstone, carbonate rocks, ·and granite. The flow from springs generally is not used by the fort, but it is sufficient to supply the entire water demand during some periods. Spring flow, if used to supplement the ground-water supply, will decrease the draft on the ground-water reservoir in the two basin-fill units; or it could be used for artificial recharge to these aquifers. A second well field, if developed in the North Gate-Libby Field area, would partly accomplish the same result by decreasing the heavily concentrated draft on the ground-water reservoir of the Fort Huachuca well field, and by utilizing ground water that now moves unused northeastward to the San Pedro River.

Arizona↗