| Abstract: | Avra Valley is a north-trending alluvial basin about 15 mi west of Tucson in Pima and Pinal Counties in south-central Arizona. The valley includes about 520 sq mi of which about 100 sq mi is in the San Xavier Indian Reservation. The basin is bounded on the east by the Tortolita, Tucson, and Sierrita Mountains and on the west by the Picacho, Silverbell, and Roskruge Mountains. The climate of the valley is semiarid, the average annual precipitation ranges from 8 to 12 in., and the average annual lake evaporation ranges from 58 to 62 in. Two major ephemeral streams--Santa Cruz River and Brawley Wash--drain the area. Santa Cruz River and Brawley Wash and their tributaries provide a source of recharge to an extensive alluvial aquifer that underlies the valley floor. Since 1940, the amount of groundwater pumped from the aquifer has been greater than the amount of natural recharge from infiltration and underflow. Overdraft of the aquifer resulted in substantial water level declines throughout the valley. Until 1969, use of groundwater in Avra Valley was for irrigation. Since 1969, the city of Tucson has pumped and transported groundwater for municipal use in the adjacent Tucson basin from lands that were purchased and retired from agriculture. The purpose of this report is to describe groundwater conditions in Avra Valley as of 1985. A brief discussion of the geohydrologic setting and history of groundwater development are given to define aquifer characteristics, changes in groundwater levels, and groundwater pumpage since 1940. (Lantz-PTT) |
| Genre: | USGS Numbered Series |
| ProdID: | 44377 |
| Citation Author: | Cuff, Melinda K.; Anderson, S. R. |
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| Citation Language: | ENGLISH |
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| Citation Phsyical Description: | 4 maps on 3 sheets ; 41 x 23 cm., sheets 89 x 123 cm. and smaller, folded in envelope 31 x 24 cm. |
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| Citation Series: | Water-Resources Investigations Report |
| Citation Series Code: | WRI |
| Citation Series Number: | 87-4192 |
| Citation Search Results Text: | Ground-water conditions in Avra Valley, Pima and Pinal Counties, Arizona -1985; 1987; WRI; 87-4192; Cuff, Melinda K.; Anderson, S. R. |
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| Citation Year: | 1987 |
| Type: | citation/reference |
| Text: | Ground-water conditions in Avra Valley, Pima and Pinal Counties, Arizona -1985; 1987; WRI; 87-4192; Cuff, Melinda K.; Anderson, S. R. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/usgs_thumb.jpg |
| Date Other: | Sat, 1 Jan 1994 00:00 -0600 |
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