I Jlinera! Classification Branch If yon do not need this report after it has served your purpose, please return it to the Geological Survey, using the official mailing label at the end UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGY AND GROUND-WATER RESOURCES OF THE VALLEY OF GILA RIVER AND SAN SIMON CREEK, ARIZONA GEOLOGICAL SURVEY WATER-SUPPLY PAPER 796 F / - J. -> UNITED STATES DEPARTMENT OF THE INTERIOR Harold L. Ickes, Secretary GEOLOGICAL SURVEY W. C. Mendenhall, Director Water-Supply Paper 796 F GEOLOGY AND GEOUND-WATEB BESOUBCES OF THE VALLEY OF GILA BIVEB AND SAN SIMON CBEEK, GBAHAM COUNTY, ABIZONA BY MAXWELL M. KNECHTEL WITH A SECTION ON THE CHEMICAL CHARACTER OF THE GROUND WATER BY E. W. LOHR Contributions to the hydrology of the United States, 1937 (Pages 181-222) UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON : 1938 For sale by the Superintendent of Documents, Washington, D. C. ------ Price 35 cents CONTENTS Page Abstract__________ ________ ___________________________________ 181 Introduction.____________________________________________ _________ 183 Scope of report.__________________________________ 183 Acknowledgments. _ ___________________________________________ 183 Location and geography _ __________________________ 183 Maps and surveys-____________________________________________ 185 Routes of travel__ _ ____________________________________ 185 Towns and settlements. ________________________________ 186 Population____._______ __________________________________ 186 Climate _______________________________________________ 186 Native vegetation.______________________________________ 187 Agriculture. ________________________________________ 187 Geomorphology __________________________________________ 188 San Simon Valley _ ____________________________________________ 188 Gila Valley.__________________________________________________ 190 General features______ ___________________________________ 190 Upper terrace.----...----_______ _____________________ 192 Lower terrace____________________________________________ 193 Alluvial plains. _____ ____________________________ 193 Geology-________________.._____-___--_________-_______-__----___- 194 Structure--___________________________ _____________ 194 Metamorphic and igneous rocks_ _ _______________________________ 195 Sedimentary rocks.____________________________________________ 196 Gila conglomerate,________________________________________ 196 General features. _______________ r _________________- 196 Fossils. ______________________________________________ 198 Pleistocene (?) terrace gravel._______________________________ 200 Quaternary alluvium.. _____________________________________ 200 Deep-well records___________________ _____________________ _ 202 Summary of Tertiary and Quaternary history _ ___________________ 204 Water resources._ __________________^______________l____J__----__- 205 Summary _________________________________ _________ _______ 205 Municipal water supplies._________ ____________________________ 206 Surface-water irrigation. _________________________________ 206 Ground water_ ____________________________________________ 207 Wells in alluvium________________________________________ 207 Wells in fanglomerate phase of the Gila conglomerate._________ 208 Wells in lake beds of the Gila conglomerate.__________________ 208 Wells in the deep sands..______-______-_--__------___----__ 212 Springs_________________________________________________ 214 Depth-temperature relations._______________________________ 217 Chemical character of the ground water, by E. W. Lohr________ 217 Analyses and well records.____________________---__----____ 221 in IV CONTENTS ILLUSTRATIONS Page PLATE 45. Topographic map of Graham County and vicinity, Arizona____ 184 46. Map showing geology, wells, and springs in parts of the valley of the Gila River and San Simon Creek, Graham County, Ariz__________________________________________ In pocket 47. A, View looking north over irrigated lowlands along the Gila River near Solomonsville; B, View looking northwest down San Simon Valley from a point near Tanque______________ 192 48. A, View looking north along San Simon Creek near Solomons­ ville; B, San Simon Creek near Tanque_-----___------___- 192 49. A, Remnants of upper terrace on flank of Graham Mountains; B, View looking south toward Graham Mountains from point near Thatcher.__________________________________ 192 50. A, Lake beds exposed at Red Knolls "desert theater", in valley \% miles southwest of Ashurst; B, Gila conglomerate on Big Spring Wash, near center of T. 5 S., R. 25 E_______________ 192 51. A, Badlands developed in fossiliferous lake beds about 2 miles west of Bear Springs, T. 7 S., R. 23 E.; B, Fossiliferous lake beds near 111 ranch, in sec. 27, T. 8 S., R. 28 E__________ 200 52. A, Diatomite with thin chert layers in lake beds 1 mile east of 111 ranch; B, Cienaga Springs, in Jacobson Wash, east of Cactus Flat________.____________--______--___--__-_-_ 200 53. A, Flow of warm water from Final Oil Co.'s Whitlock No. 1 well, in sec. 36, T. 10 S., R. 28 E.; B, Indian Hot Springs____ 216 FIGURE 29. Index map of Arizona, showing area considered in this report and other water-supply papers of the Geological Survey. __ 184 30. Section showing artesian conditions in the lake beds of the valley of the Gila River and San Simon Creek____________ 210 31. Map of Pima, showing locations of wells___________________ 211 32. Map of Safford, showing locations of wells ________________ 212 33. Map of Thatcher, showing locations of wells _______________ 21S INSERT Page Records of wells in Graham County, Ariz_______________________-____ 222 GEOLOGY AND GROUND-WATER RESOURCES OF THE VAL­ LEY OF GILA RIVER AND SAN SIMON CREEK, GRAHAM COUNTY, ARIZONA ______ By MAXWELL M. KNECHTEL ABSTRACT The valley formed by the Gila River and San Simon Creek, in Graham County, Ariz., is an intermontane trough 10 to 20 miles wide that extends from the San Carlos Indian Reservation many miles southeastward. It is bordered on the southwest by the Chiricahua, Dos Cabezas, Pinaleno, Santa Teresa, Turnbull, and Mescal Mountains and on the northeast by the Peloncillo and Gila Mountains. The Gila River, a perennial stream, enters the trough northeast of Solomonsville through a gorge in the Peloncillo Mountains and flows northwestward to Coolidge Dam, where it turns southwest and leaves the relatively broad valley through a gorge in the Mescal Mountains. San Simon Creek, an intermittent stream, rises at the head of the trough and flows northwestward to join the Gila near Solomons­ ville. Along the Gila River is an alluvial lowland plain, 1 to 3 miles wide, which is underlain, to an average depth of about 100 feet, by Quaternary silt, sand, and gravel deposited by the river. This plain, large portions of which are irrigated by water from the river, includes most of the crop-producing land of Graham County. Similar low plains lie along several of the larger tributary arroyos. Higher land borders the alluvial plains and grades gently upward on each side of the valley to the base of the steep mountain slopes. This higher land is terraced, and two principal terrace levels have been recognized. The terraces, the smooth upper surfaces of which are of the pediment type, are capped by naturally cemented gravel, which in most places is not more than 10 feet thick. The gravel on the terraces is believed to have been deposited in Pleistocene time, earlier than the materials in the low-lying alluvial plains, and it rests on still older (upper Pliocene) deposits, which are mostly lacustrine but partly fluviatile in origin and which rep­ resent the Gila conglomerate. The Gila deposits, which carry fossil mammals, am­ phibians, fresh-water mollusks, silicified wood, and diatoms, consist chiefly of clay in the central part of the valley and of sand and gravel along the valley margins. They crop out prominently 011 the steeply sloping escarpments of the terraces and along most of the watercourses but are hidden elsewhere under the alluvial deposits and terrace gravel. Beds of water-bearing sand and gravel occur in all the deposits, but the principal ground-water supply for the valley is obtained from wells in the Pliocene lacustrine strata and the Quaternary alluvium. In the Quaternary alluvium underlying the lowland plains beds of water-bearing sand and gravel are numerous but irregular. Any one bed pinches out laterally in all directions and generally underlies only a small area. Consequently, the ver­ tical spacing and the number of water-bearing layers encountered in sinking wells differ from place to place. The water in these layers is under little or no artesian pressure. 181 182 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1937 The Pleistocene (?) terrace gravel yields little water, and most of this water issues as springs on the escarpments of the terraces at the contact between the permeable gravel and the underlying dense lacustrine clay. The upper Pliocene (Gila) deposits yield water to wells from beds of permeable sand and gravel, which in general lie nearly horizontal between thick layers of relatively impervious silt and clay. The water-bearing beds are commonly most numerous and thickest toward the sides of the valley, and many of them pinch out toward the center of the valley. A typical section across the valley shows the Gila beds to be chiefly impervious lacustrine clay beneath the central part and coarse fluviatile conglomerate at the valley margins, with nearly horizontal thin tongues or sheets of