D.W.R HYDROLOGIC MAP SERIES REPORT NO. 34 PREPARED IN COOPERATION WITH THE UNITED STATES GEOLOGICAL SURVEY THE DEPARTMENT OF WATER RESOURCES DEPTH TO WATER AND ALTITUDE OF THE WATER LEVEL SHEET 1 OF 2

114 113 112 111 110 109 Based on 1968 data, a small elliptical cone of depression was first described by Roeske and Werrell, (1973, p.16). The 37 37 With the exception of the Pantano (?) Formation, all of the previously mentioned basin-fill units are also present in Allen Flat, depression was enclosed within the 4,150 foot contour. It encompassed about 5 square miles and was centered in section 33, however, the units are not as thick (Putman and others, 1988, p. 65). Depth to bedrock in the Allen Flat sub-basin has been Township 21 South, Range 20 East. The major axis of the elliptical cone was northeast-southwest in orientation. Data col- estimated to be from 1,600 to 3,200 feet (Oppenheimer and Sumner, 1980, map). lected by the U. S. Geological Survey in the winter of 1977-78 supports Konieczki’s (1980, sheet 1) reference to the small depression centered within the 4,150 foot contour near Sierra Vista-Fort Huachuca. Putman and others (1988, p.98), using GROUNDWATER OCCURRENCE data collected in the winter of 1985-86, stated that the cone of depression within the 4,150 foot contour still extended in a northeast-southwest direction, and had increased areally to the east and southeast of Sierra Vista, to about 7.5 square miles. A T R 21 E The predominant aquifers in the Upper San Pedro Basin are the basin-fill deposits and the floodplain alluvium (Roeske and maximum decline of 9.2 feet was observed between 1985 and 1990 at well (D-21-21) 31CAC, while the minimum observed 36 36 decline was 2.2 feet at well (D-21-20) 35CBC for this period. 11 Werrell, 1973, p. 24). Groundwater occurs under unconfined conditions in the flood-plain alluvium and under both confined and unconfined conditions in the basin-fill deposits. S COCONINO In 1990, the cone was centered or deepest in section 33, Township 21 South, Range 20 East. The deepest part of the cone Basin-Fill Deposits could be encircled by the 4,100 foot water-level altitude contour. Water levels in wells within the influence of the depression were generally declining at approximately 0.5 to 1.0 foot per year. The depression was generally expanding in an east-south- Flagstaff KINGMAN The basin-fill deposits, consisting of the upper and lower units and the (Pantano (?) Formation), form the principal aquifer in easterly direction from the deepest part of the cone. APACHE R 22 E NAVAJO the Upper San Pedro Basin. The basin-fill deposits are stratigraphically complex. Locally, some areas exhibit confined condi- 35 35 tions, but regionally the basin-fill aquifer is unconfined (Freethey, 1982, p. 49). In Dec.2001-Jan.2002, the cone was still centered in section 33, Township 21 South, Range 20 East and the deepest part of the cone can still be encircled by the 4100 foot water-level contour. MOHAVE Holbrook T YAVAPAI Unconfined 12 Declines for 1990-Dec.2001-Jan.2002 became less pronounced north of Sierra Vista. Between Sierra Vista and Huachuca S Both the upper and lower units are good sources of groundwater, and together they produce most of the water pumped from the City declines in the 5.0 to 7.0 foot range are common, (see hydrograph J). North of Huachuca City declines are in the 1.0 to 5.0 4 foot range for the 1990-Dec.2001-Jan.2002 period, (see hydrograph I). One exception was public supply well (D-20-19) 5076 Prescott regional aquifer. Yields of 100 to 2,800 gallons per minute have been reported from wells completed in the upper and lower 2 14ADD, which declined 13.4 feet (1.2 ft/yr) since 1990. N 5080 units (Roeske and Werrell, 1973, p. 13). The Pantano (?) Formation is generally well cemented and not a reliable aquifer, but well yields up to several hundred gallons per minute have been reported (Roeske and Werrell, 1973, p. 10). In Dec.2001- Jan.2002, measured depths to water in the unconfined areas of the regional aquifer ranged from less than 100 feet to nearly 600 South of Sierra Vista toward Nicksville a wide range of declines, as well as rises, were recorded on either side of State Route W E 34 34 28 92. The largest declines occur in public supply wells, ranging from 26.4 to 35.4 feet since 1990. The closer the proximity to the 5002 feet below land surface. LA PAZ Huachuca Mountains foothills, the more varied the water levels become, ranging from a decline of 8.7 feet to a rise of 16.6 196 GILA 4223 feet. Many of the wells in the area are completed in either the pediment aquifer or in fractured hardrock. In either case, these S 13 PHOENIX Confined 5 5097 136 5095 wells are more susceptible to rainfall or drought conditions than those completed in the regional aquifer. T 4234 10 13 5315 The Upper San Pedro Basin has long been recognized as an area with hundreds of artesian wells. Nearly all of these wells are MARICOPA located in two geographically small areas along the San Pedro River, where silt and clay layers restrict vertical movement of Tombstone S groundwater. The larger of the artesian areas is located roughly between Land and Pomerene, and is about 12 miles long and 2 Declines are common in the Tombstone area, ranging from less than 1 foot to as much as 23 feet. Many of the declines are in 33 33 to 3 miles wide. This area includes Benson and St. David. The confined area near Benson may be more laterally extensive than shallow wells (windmills) located in or near washes. These declines clearly reflect the drought conditions which have persisted YUMA 722 PINAL GRAHAM 4250 GREENLEE previously thought (Fluid Solutions, Inc, 2000). A second area, about 10 miles long and 1 mile wide, is located between in recent years. Three deep (600-890 feet) public supply wells exhibit declines ranging from 3.3 feet to 23.1 feet. Hereford and Palominas. In these two areas, deep wells drilled in or adjacent to the flood plain of the San Pedro River encounter 4200 Yuma confined waters (Heindl, 1952, p. 70). Gravel beds of the lower basin fill are overlain by up to several hundred feet of silt and Naco clay. Depths to the confined waters vary depending upon location. The shallowest is in the Hereford-Palominas area, where Among the sharpest declines in the basin, are those having occurred in the Naco area. These declines are consistently in the TUCSON well depths of about 200 feet are required (Roeske and Werrell, 1973, p. 12). At St. David, and south to Land, well depths of mid-20 foot range. The range of declines was from 9.8 feet to 32.1 feet. However, farther west, toward the San Pedro River, T 300 feet and deeper are required to reach the confined aquifer. The deepest confined waters are found between Benson and changes ranged from a rise of 1.0 to a decline of 4.1 feet, which are more consistent with those observed in the rest of the PIMA Pomerene, at depths of 500 to 1,000 feet. Confined groundwater has also been encountered in the upper unit of the basin fill, basin. 14 32 32 where sand and gravel beds are locally overlain by clay and silt lenses. Flowing discharges from these wells are much less than S COCHISE the flowing wells completed in the lower basin fill. In December of 1990, approximately 150 artesian wells were visited while United States Border to State Route 90 (including Palominas-Hereford) 114 collecting data for HMS 31. Of that group, 47 flowing wells were observed. Many other flowing wells were not accessible, and The reach of the San Pedro River from the United States-Mexico Border, to State Route 90 has shown no remarkable change SANTA 113 CRUZ some wells flow only seasonally. Of the artesian wells that were not flowing, depth to water ranged from a few inches to as since 1990. This area, which includes the communities of Palominas and Hereford, reflects water level changes ranging from declines of 4.9 feet, and rises to 7.0 feet. Most of the wells show a change of plus or minus 3 feet. When considered over an 11 Nogales much as 50 feet below land surface. In Dec.2001-Jan. 2002, 16 flowing wells were visited in the Benson/Pomerene area and 17 in the St. David/Land area. This is not intended to imply that there are less flowing wells now than in 1990, just that the year period, these changes are quite small. Hydrograph (S) shows stable water table conditions in the Palominas area. West of 112 R 18 E R 19 E emphasis of the Dec.2001-Jan.2002 data collection was to obtain water levels from wells that had previously been measured. the San Pedro River in the eastern half of T22S, R21E, wells show declines in the 2.0 to 7.0 foot range. However, Hydrograph R 20 E 4100 111 110 109 No effort was made to seek-out flowing wells. (P) shows that no drastic change has taken place. 43 3304 4000 T 0 50 100 MILES In 1903, a maximum discharge of 80 gallons per minute was observed in the artesian wells of the Upper San Pedro Basin. The WATER QUALITY 48 average discharge was about 10 gallons per minute (Lee, 1905, p. 169). In December of 1990, estimated discharges ranged 3310 51 15 38 3309 3326 3900 from over 50 gallons per minute to a trickle. Although no flowing wells were observed in the Hereford-Palominas area, some No water quality samples were taken by ADWR for this update of HMS 31. This was due to budgetary and staffing con- 11 32 65 3350 S 4198 3350 30 3315 wells were reported to flow seasonally. 28 straints. Text below is taken largely from Barnes, 1997 (HMS 31). 196 3340 3800 3462 30 36 3514 0 50 100 150 KILOMETERS 3358 4944 3600

47 3500 3700 19 3398 Flood-Plain Alluvium The groundwater of the Upper San Pedro Basin is generally of good chemical quality. Of the 155 total samples, the MCL’s for 4011 3500 3400 3650 50 3372 32 INDEX MAP SHOWING AREA fluoride or dissolved solids were exceeded in only 25 wells. Of the 25 wells in which one or both of the MCL’s were exceeded, 47 3374 37 48 3398 OF REPORT (SHADED) 3413 3388 The flood-plain alluvium is more porous and permeable than the basin fill. However, due to its limited areal extent, it is only an 20 of the wells are located either in the confined part of the regional aquifer or in the flood-plain alluvium. Water from these 55 3450 3550 29 3393 41 3831 3394 important aquifer locally, along the flood plains of the major watercourses of the valley. Water levels are generally less than 50 two areas is generally used for irrigation. When the basin is viewed in its entirety, these two areas represent a very small 38 31 44 33 3398 550 feet below the land surface, and fluctuate seasonally in response to a combination of factors including riparian use, pumpage percentage of the total area. 3809 3600 3399 60 3387 3420 3725 3800 37 6 45 and recharge from river flow. Because of its high permeability and close proximity to the river, the flood-plain alluvium is easily 10 3400 SCALE BARS T 3551 3700 3785 3412 3650 37 43 recharged, and rapid recovery rates in wells are common. Many of the irrigation wells in the basin obtain water from the flood- Water samples from 155 wells and springs were collected in 1990 for the HMS 31 (Barnes, 1997). Of that number, 59 were 37 3408 3456 303 133 16 3402 STATUTE MILES 30 3504 4185 5 0 5 plain alluvium (Roeske and Werrell, 1973, p. 11). Discharges from wells commonly range from 200 to 1,800 gallons per detailed analyses and the remainder were analyzed for fluoride, specific-conductance and pH only. No samples were collected 3456 87 3900 549 R 23 E S 1 3454 minute, and some have produced up to 2,000 gallons per minute (Roeske and Werrell, 1973, p. 13). for the present HMS. 3610 551 3559 76 3630 3457 4200 38 4000 4100 3492 3900 Secondary Sources The maximum contaminant level (MCL) for fluoride in Arizona public drinking water is 4.0 milligrams per liter (mg/L), as 5 0 5 10 KILOMETERS established by the U. S. Environmental Protection Agency (1986, p. 11396-11397) and the Arizona Department of Environ- 224 213 61 41 80 3541 433 3625 3519 3474 3450 A pediment or isolated alluvial aquifer is located along the northeastern slope of the Huachuca Mountains, south of Sierra Vista. mental Quality (1989, p. 7). The MCL is an enforceable standard set by the U. S. Environmental Protection Agency for 227 3642 464 39 11 65 3853 485 490 3616 3587 3488 3495 527 3633 66 Very shallow water levels, some less than 30 feet below land surface, have been measured in this area. Other secondary sources drinking water. States must comply with this standard, but are free to set levels which are more stringent. 3620 26 3638 482 3602 235 3499 3598 WATER-LEVEL CONTOUR INTERVAL 100 FEET of groundwater include the crystalline rocks and consolidated sedimentary rocks, which make up the mountains surrounding 3985 9 242 3571 158 WITH SUPPLEMENTARY CONTOURS AT 25 AND 50 FOOT INTERVALS the basin. Where sufficiently fractured and saturated, these rocks may yield a few gallons per minute to wells. Dissolved-solids concentrations may be approximated by multiplying specific-conductance values by 0.6, which is the approxi- 330 3978 3587 3901 516 11 106 4100 545 128 6 32 3619 mate ratio of dissolved solids in mg/L to specific conductance in microsiemens per centimeter at 25°C.(mS/cm), The U. S. 3624 30 3539 T 3635 3518 3574 3508 506 471 3510 36 4000 3614 3609 TRANSVERSE MERCATOR PROJECTION Recently the presence of a limestone aquifer in the Whetstone Mountains has been emphasized by the discovery of Kartchner Environmental Protection Agency has established the secondary maximum contaminant level (SMCL) for dissolved solids at 145 64 3599 32 46 17 4261 3616 3518 24 29 3580 Caverns, now a world-renowned state park. Limestone caves also exist in the Huachuca Mountains in the southern part of the 500 mg/L, which is approximately equivalent to a specific-conductance value of 833 mS/cm. The SMCL’s are guidelines only, 30 3625 37 95 3611 40 3607 BLACK NUMBERED LINES INDICATE THE 10,000 METER UNIVERSAL TRANSVERSE MERCATOR 338 3515 55 S 4430 3618 basin, although they do not have the importance of Kartchner Caverns. A publication by Graf (1999) discusses the hydrology of and are not enforceable standards (U.S. Environmental Protection Agency, 1988, p. 9). The SMCL’s are based on aesthetic 4143 10 3685 GRID, ZONE 12 1977 MAGNETIC DECLINATION FROM TRUE NORTH VARIES FROM 13 DEGREES 29 3625 49 the cave. There are three aquifer systems within park boundaries. Graf (1999) indicates a degree of hydraulic separation qualities such as taste, odor and color. Water with contaminant levels above the SMCL are not necessarily a health risk. 4569 3609 27 (230 MILS) EASTERLY FOR THE CENTER OF THE WEST EDGE 121EASt CENTER OF THE EAST 38 3603 EDGE between the regional basin fill aquifer and the park aquifers. The hydrologic significance of the water in the limestones is not 4560 24 5 fully understood at this time (Don Pool, U.S. Geological Survey, per. commun., 2003). Flood-Plain Alluvium 3566 3636 21 48 9 3601 242 3569 57 3700 366 4198 3596 3581 3794 Numerous springs are located in limestones in the surrounding mountains. Discharges from these springs are generally smal l Some of the poorest quality water in the basin is found in the flood-plain alluvium. Between St. David and the Narrows, the 29 103 3693 3757 and may have periods of no flow. The most significant springs in the basin are located in Garden Canyon in the Huachuca specific-conductance values are the highest in the basin, ranging from 850 to 2,800 µS/cm, or approximately 510 to 1,680 mg/ 3700 32 360 3633 66 6 3693 3810 Mountains, where combined maximum discharge has reached 1,800 gallons per minute (Brown and others, 1966, p. 36). Prior L dissolved solids in 1990. South of St. David, specific-conductance values ranged from 307 to 620 mS/cm, or approximately 75 3624 T 3647 9 29 4200 to the summer of 2003, many of the springs in Garden Canyon were dry, or near dry (Don Pool, U. S. Geological Survey, per. 184 to 372 mg/L dissolved solids, decreasing in value with distance south of St. David. Fluoride values ranged from a low of 3800 69 3706 71 16 3622 4845 5169 INTRODUCTION 3686 41 4800 commun, 2003). 0.2 mg/L northwest of Hereford to a high of 3.0 mg/L near St. David. North of St. David values range from 0.5 to 1.9 mg/L and 18 46 3661

1 3800 3900 3659 3680 south of St. David from 0.2 to 1 .0 mg/L. Average water temperature in the flood-plain alluvium is about 19.6 °C (67.3 °F). 75 S 4000 3660 59 In December, 2001 and January, 2002 the Arizona Department of Water Resources field staff collected data on groundwater RECHARGE 25 71 5601 3665 4774 elevations in numerous wells throughout the Upper San Pedro Basin of southeastern Arizona. These data are presented in this 83 Basin–Fill Deposits 62 3662 609 3663 4231 report as maps of groundwater elevation contours and changes in water level, including hydrographs of selected wells showing The aquifers in the Upper San Pedro Basin are recharged by mountain-front runoff, river and streambed infiltration, underflow 4300 5 12 72 changing water levels over time. The Department previously produced such maps showing groundwater conditions in 1990. 3745 13 5384 from Mexico, and seepage from applied irrigation. Due to high evapotranspiration rates, direct recharge from precipitation In the artesian area from St. David north to Benson, specific-conductance values range from 180 to 550 µS/cm, or approxi- 5048 4874 These maps were published as Hydrologic Map Series (HMS) 31 in 1997 (Barnes, 1997). In 1990 the Department staff visited seepage is negligible. The average annual regional recharge is estimated to be about 29,600 acre-feet per year (Arizona Depart- mately 108 to 330 mg/L dissolved solids, which is well within the SMCL limits. Fluoride values range from 0.1 to 8.8 mg/L; 27 4600 3719 11 1,075 wells and obtained water level data from 753 of them. In 2001-2002 the Department staff revisited the 753 wells 3900 4400 5154 ment of Water Resources, 2004). 220 the higher values generally occur from just south of Benson to Land. The temperature of the artesian waters averages 24.2 °C 3825 4500 previously measured, as well as obtaining additional measurements from new wells. Hydrographs depicting changes in water 30 137 (75.6°F). There is a small area from just southwest to northwest of Pomerene in which five flowing wells were sampled. These 4015 3822 28 levels in specific wells are also presented in this report. Much of the text from Barnes (HMS 31, 1997), remain valid to discuss 7 DISCHARGE wells have anomalously high temperatures which range from 28 °C to 30 °C and average 28.9 °C (84°F). Each of these wells 5102 T 5228 the hydrology and geology of the basin. That text has been updated where necessary to discuss new geologic information, 4100 172 is at least 1,000 feet deep. Other artesian wells in the same general area produce water in the 20°C to 25°C range. 5113 19 107 399 429 recent water level data, and to update water use estimates. Groundwater is discharged in the Upper San Pedro Basin by both natural and artificial means. Freethey and Anderson (1986, 4047 4023 4376 197 443 369 sheet 3), estimate that less than 1,000 acre-feet per year of groundwater was discharged to the Lower San Pedro Basin as S 193 3825 4647 4729 Only five of the wells sampled in the unconfined regional aquifer produce water which exceeds one of the MCL’s for fluoride 4093 4000 4100 18 50 496 GENERAL SETTING outflow under pre-developmental conditions. This figure is likely little changed today. Contributing to total discharge are wells, or dissolved solids. This certainly is supportive of historical claims that the regional aquifer is of good quality. Fluoride values 330 4134

4150 4208 79 4249 220 4200 4090 4821 103 evapotranspiration, evaporation of surface water from the perennial reach of the San Pedro River (Hereford to Fairbank), in the unconfined regional aquifer range from 0.1 mg/L to a high of 4.0 mg/L. Specific-conductance values range from 160 142 4092 3835 303 4112 4072 The Upper San Pedro Basin is an intermontaine valley which includes approximately 1,875 square miles in southeast Arizona. contributions from the groundwater systems to the San Pedro and Babocomari Rivers as baseflows, and municipal, agricul- µS/cm to 3,100 µS/cm, and average 448 µS/cm. Temperatures range from 17 °C to 29 °C, and averages 22.2 °C (72°F). 154 25 4755 4250 363 108 229 20 63 The basin is bounded on the west by the Huachuca, Whetstone, and Rincon Mountains, and on the east by the Mule, Dragoon, 213 30 4097 tural, industrial and domestic wells. Numerous springs along the San Pedro River also contribute to total groundwater dis- 4804 4118 99 4655 4795 4117 4293 410 134 4700 4084 31 223 4140 Little Dragoon and Winchester Mountains. The basin extends approximately 58 miles along the San Pedro River, from the charge. Discharge for most of these springs has not been quantified. Production from wells and riparian evapotranspiration are High sulfate and/or nitrate levels were detected in a few wells in the Upper San Pedro Basin. These wells are mainly located in 4716 4600 143 37 4394 4117 4117 3813 464 193 International boundary with the Republic of Mexico on the south, to the Narrows, approximately 11 miles north of Benson. the major sources of groundwater discharge. Public supply wells (including domestic wells and military uses) and irrigation 4146 the flood-plain alluvium, roughly from St. David to the Narrows. The sulfate MCL of 250 mg/L was exceeded at three wells 107 109 252 4528 311 228 4688 4661 4124 4138 4122 The north sloping, north-to-northwest-trending valley ranges from 6 to 39 miles wide, and is divided into two sub-basins, Allen wells are the largest groundwater pumpers, followed by industrial users. In 2002, an estimated 26,000 acre-feet (Arizona and the nitrate MCL of 10 mg/L was exceeded at two wells. One well, (D-19-20) 3ODAA (360 mg/L), southeast of the T 4200 65 4500 167 120 4088 191 Flat and Sierra Vista. Department of Water Resources, 2004, table 2, p. 42 ) was pumped in the Upper San Pedro Basin; 16,100 was pumped for Whetstone Mountains, completed in the regional aquifer produces water with high sulfate concentrations. 276 4123 4115 4571 231 20 4134

20 4129 4620 municipal uses, 7,500 for agricultural uses, and 2,400 for other uses. (Arizona Department of Water Resources, 2004 ). A large 4300 41 53 The basin is drained by the San Pedro River and its main tributaries, the and Tres Alamos Wash. The San 4642 number of flowing wells, exist in the basin, especially near Benson and St. David. In spite of the large numbers of flowing wells, Water from 13 springs was analyzed for HMS 31. Fluoride values range from 0.5 to 1.9 mg/L. Specific-conductance values 26 4400 31 4521 S 152 4729 4109 4429 Pedro River flows northward from its headwaters, 25 miles south of the International boundary. The river enters the basin just total discharge from this source is thought to be quite small, owing to low rates of flow from each well. In 1990, an estimated 27 range from 210 to 833 mS/cm, which is approximately 126 to 500 mg/L dissolved solids. Temperatures range from 7.5 °C at 4108 21 42 10 113 south of the community of Palominas at an altitude of 4,275 feet, and exits at the Narrows, at an altitude of 3,309 feet, yielding 37,000 acre-feet of goundwater was pumped, not including riparian demand. The peak year for pumping was 1981, when spring (D-17-23) 04BCC to 24.5 °C at spring (D-17-23) 18AAD, both located in the Dragoon Mountains. 159 4679 4083 4160 4187 4139 159 a topographic gradient of nearly 17 feet per mile. Within the Upper San Pedro Basin the San Pedro River could be considered 75,000 acre-feet were pumped. Since 1966, 1,412,000 acre-feet of groundwater has been pumped from the Upper San Pedro 4129 4800 50 a perennial interrupted watercourse (Meinzer, 1923). The perennial reach runs from just south of Highway 90 to south of 4780 28 Basin (Anning Duet, 1994, sheet 1 ). Pre-1966 pumping records are not available for this basin. Riparian groundwater demand 4102 4900 209 228 49 148 Fairbank. has been estimated at about 19,800 acre-feet for 2002, (Arizona Department of Water Resources, 2004). SELECTED REFERENCES 4126 4117 4976 4077 96 152 230 209 4174 436 26 5000 4823 20 4125 4081 5019 4615 4000 4164 The climate in the Upper San Pedro Basin is semiarid, characterized by hot summers and mild winters (Roeske and Werrell, MOVEMENT AND STORAGE 299 293 262 4100 Arizona Department of Water Resources, 2004, Groundwater Resources of the Upper San Pedro Basin, Arizona, 77p. (in 71 27 159 293 262 35 4113 4141 4194 83 46 4904 4572 4208 4107 4128 172 4915 81 4123 4082 1973, p. 9). Rainfall primarily occurs during two peak periods. During the months of December, January and February gentle review) 5004 4100 183 54 4769 63 126 4077 4796 225 18 4977 4701 300 rains, occasionally of long duration, are typical. Intense, short-duration rainfall resulting from monsoonal thunderstorms make Direction of groundwater flow generally mirrors surface-water drainage in the basin. Groundwater moves from the mountain 4787 3980 456 483 4140 T 63 16 35 4144 4097 14 185 July and August the wettest months of the year. May is the driest month of the year, typically with little or no recorded fronts and higher elevations toward the center of the basin, then moves in a north-northwest direction along the axis of the 4949 16 98 4763 4135 3991 89 Anning, D.W., Duet, N.R., 1994, Summary of ground-water conditions in Arizona, 1987-90: U. S. Geological Survey 490 207 4085 4942 4777 505 63 4071 4120 445 4146 21 4125 4110 186 78 3992 precipitation. Average annual rainfall ranges from 11 inches at Benson to 15 inches in the area around Fort Huachuca-Sierra valley. Natural flow direction has been disrupted near Sierra Vista due to the development of a significant groundwater depres- Open-file Report 94-476, 2 sheets. 16 583 4121 33 4141 4172 207 5132 4165 526 493 4892 464 11 4258 Vista, to more than 22 inches at the Coronado National Memorial. Snowfall contributes a minor amount of precipitation in the sion. Water under the influence of the depression now flows toward its center. In the southern part of the Allen Flat sub-basin 7 15 4094 4108 314 121

S 4400 4116 4069

5043 37 4836 430 4126 4059 4500

4823 4600 9 4115 Upper San Pedro Basin, with a yearly total of 1.5 to 3 inches throughout most of the valley floor, and from 5 to 15 inches in the groundwater flows to the south and west, into the Sierra Vista sub-basin. ln places, groundwater can also freely move between 108 4700 Arizona Department of Environmental Quality, 1989, Public and semi-public water supply systems rules, State of Arizona: 45 33 309 160 4970 5216 4300 5075 13 4797 533 4131 foothills of the mountains. Much more snow and rainfall occurs in the mountains surrounding the basin. June is the hottest 5045 4947 4094 alluvial units within the aquifers. Some exchange of water between the confined parts of the regional aquifer and the flood- Arizona Department of Environmental Quality, Phoenix, Arizona, 44 p. 222 29 25 403 121 month of the year, and average daytime temperatures range from the mid-to-high 90’s°F near Benson to approximately 90°F 4157 4033 plain aquifer can also take place due to well casings perforated in both aquifers and due to corroded well casings. 4995 4127 4179 28 4200 534 106 4947 10 180 182 in the southern part of the basin. The coolest month is January, when average daytime highs range from the low 60’s°F near 5047 4113 443 154 Arizona Department of Water Resources, 1990, Preliminary survey report for the San Pedro River watershed: Volume I, 5015 415 327 4150 4073 4117 4166 128 34 35 4135 4149 12 4172 Benson to the high 50’s°F in the southern part of the basin. Extremes of 116°F at Benson in June 1904, and -7°F at St. David There are an estimated 20,000,000 acre-feet of groundwater stored in the Upper San Pedro Basin (ADWR, 2004). This General Assessment, 548 p. 5041 5016 5040 371 349 7 13 8 480 117 4068 554 4130 4131 in December 1978 have been recorded (Sellers and others, 1985, p. 86-93, 112-114, 132, 133). 5052 5084 4135 135 4183 2 estimate is considerably less than the estimate reported in HMS 31 because a new geophysical study (Gettings and Houser, 37 4123 518 114 38 143 4189 4092 5065 4122 408 5091 5092 4188 129 3 2000) indicates that bedrock is more shallow in the basin than previously assumed, thus limiting the vertical extent of the Arizona Department of Water Resources, 1994, Arizona Water Resources Assessment: Volume II, Hydrologic Summary, 28 4200 4150 4197 4179 4094 T 5094 366 186 141 251 4183 4184 Anglo settlement of the Upper San Pedro Basin was hastened by mining which brought early settlers to the area around Bisbee aquifer. 236 p. 15 4250 4189 127 59 5081 34 4564 55 174 4193 393 22 5091 34 4806 4685 226 4191 and Tombstone. The first homesteads were established in the late 1800’s. Mormons settled at St. David in 1877, and Camp 4217 4202 18 5092 371 4300 4202 196 Huachuca, now Fort Huachuca, was established by the U.S. Army the same year (Barnes and Granger, 1960, p. 40, 49). To 5142 20 408 4200 WATER LEVEL CHANGES Barnes, W. C., Granger B. H., 1960, Arizona Place Names: University of Arizona Press, 519 p. S 392 124 5308 4241 27 4368 179 4200 412 supply the needs of the booming mining districts, agriculture became important, resulting in the need for reliable sources of 4953 21 4203 116 4864 4218 4209 11 water. Early reports mention that groundwater under artesian pressure was first noted in 1887. Water reportedly flowed for 228 201 Ground water levels in the Upper San Pedro Basin fluctuate seasonally in response to pumping and recharge, especially in the Barnes, R.L., 1997, Maps Showing Groundwater Conditions in the Upper San Pedro Basin,Cochise, Graham and Santa 4879 361 199 120 4150 4216 4210 4114 131 4361 4212 several hours from a fissure caused by a strong earthquake (Lee, 1905, p. 169). There is evidence to support such a claim as an flood-plain alluvium along the San Pedro River. Recent drought conditions in the Southwest have affected the Upper San 4794 62 253 172 Cruz Counties, Arizona – 1990. Department of WaterResources Hydrologic Map Series Report Number 31. 4223 9 25 36 4733 4225 4141 estimated magnitude 7.2 earthquake centered 30 miles southeast of Douglas, caused damage throughout southeastern Arizona Pedro Basin, and groundwater declines within the basin reflect the lack of recharge, particularly along stream courses. How- 5060 4942 19 259 4821 4219 118 22 in 1887 (Fellows, 1995, p. 1). The first flowing well in the Upper San Pedro Basin, and possibly the first in the state, was drilled ever, as hydrographs point out in the following discussion, water level changes have not been drastic in the Upper San Pedro 4 35 4798 4169 4138 Brown, S. G., Davidson, E. S., Kister, L. R., Thomsen, B. W., 1966, Water Resources of Fort Huachuca Military 104 4145 141 133 290 124 4223 R 24 E in 1892 (Roeske and Werrell, 1973, p. 6). In his 1903 investigation of the valley, W.T. Lee (1905, p. 166) observed that over Basin. There are areas where decline has been historically noted, and declines in these areas has continued. The most unex- 4594 4517 4230 4249 Reservation, southeastern Arizona: U.S. Geological Survey Water Supply Paper 1819-D, 57 p. 61 33 175 237 137 87 4169 200 wells had been drilled between Benson and Fairbank, a distance of only 20 miles. pected changes have occurred in an area between Bisbee and Naco. Declines in the Bisbee-Naco area are among the largest 4157 4598 4386 4223 4218 7 4200 4168 105 88 33 observed in the basin over the 11 year period between 1990 and Dec.2001-Jan.2002. Specific areas are discussed below. T 114 4555 4188 4169 25 3 Burtell, R.T., 1989, Geochemistry and Occurrence of Ground Water in the Allen Flat Basin, Arizona. M.S. Thesis, 4791 4173 4192 9 The major cities, towns and communities in the basin include Sierra Vista, Tombstone, Huachuca City, Fort Huachuca, Benson, 4181 38 12 University of Arizona, Tucson, 164 p. 23 77 138 14 105 4182 4178 4848 161 4225 4176 St. David, Naco, Pomerene, Hereford, Palominas and Nicksville. Farming, ranching and mining are the notable industries in Hydrographs referred to are located on Sheet 2. These hydrographs were also discussed in HMS 31. Not all hydrographs 15 180 4254 4244 39 216 4200 420 S 59 53 4184 1 4760 231 the basin, with major groundwater users being farmers, the mining industry, and municipalities. In May, 2002 there were discussed in HMS 31 are discussed in HMS 34 because some wells were destroyed or were not available for measurement 5026 4197 4241 32 265 Drewes, H., 1980, Tectonic Map of Southeast Arizona. U.S. Geological Survey Miscellaneous Investigation Series Map 111 41 43 98 84 18 4208 4200 approximately 3,000 actively irrigated acres in the Upper San Pedro Basin (Arizona Department of Water Resources, 2003). 329 4224 4219 4197 293 between 1990 and Dec. 200l-Jan.2002. Discussions of the following areas are not necessarily based on well defined boundaries 4983 4231 4202 166 1—1109. 4281 103 4487 295 19 25 44 4207 273 276 4233 38 4503 or geo-political areas. They are instead discussions of gereral areas. 4211 4215 4205 4212 4564 4210 276 34 137 4454 4221 250 4228 15 270 Fellows, L. D., 1995, Kobe Earthquake, - Arizona Geology: Volume 25, Number 1, Spring 1995, 4 p. 197 36 23 123 4193 287 183 265 4725 122 60 4210 241 GEOLOGY Allen Flat Sub-basin 4278 4226 4228 4203 4354 4447 4460 202 4238 4235 4279 41 160 4516 197 87 213 166 181 42 4234 177 4444 4273 4239 37 4213 4454 4454 4500 151 Fluid Solutions, 2000, Groundwater and the City of Benson, Consulting Report, 50p. 148 4239 20 4177 T 4241 14 180 108 4534 4855 4229 243 The Upper San Pedro Basin is an elongated trough formed by the uplift of the surrounding mountain blocks relative to the Very little change has taken place in the Allen Flat sub-basin. Hydrographs (A and B) clearly show the stable conditions that 4222 4215 4432 141 110 130 4227 4445 81 24 4916 4283 blocks underlying the valley floor. The resultant mountains are made up mainly of granite, schist, gneiss, volcanics and consoli- have existed since 1990. 25 4300 4595 Freethey, G. W., 1982, Hydrologic analysis of the Upper San Pedro Basin from the Mexico-U. S. Boundary to Fairbank, 4250 4400 dated sedimentary rocks ranging in age from Precambrian to Tertiary. The structural and, to some degree, the hydrologic

4300 143 Arizona: U. S. Geological Survey Open-tile Report 82-572, 64 p. S 130 4250 113 129 39 72 40 79 116 156 106 4472 4865 4447 4447 system are affected by the Tombstone Hills which jut out into the basin between Tombstone and the San Pedro River. These Sierra Vista Sub-basin 5071 5080 4255 4431 4425 4474 4250 4434 169 157 4453 outcrops are composed of Tertiary granite and volcanics. As the surrounding mountains eroded, the basin subsequently filled 4443 Freethey, G. W., Anderson, T. W., 1986, Predevelopment hydrologic conditions in the alluvial basins of Arizona and adjacent SCALE BAR with alluvium. The estimated maximum depth to bedrock along the axis of the basin may exceed 6,000 feet in the southern North of Pomerene parts of California and New Mexico: U. S. Geological Survey Hydrologic Investigations Atlas HA-664, 3 part, and is less than 5,000 feet in the northern part (Oppenheimer and Sumner, 1980, map). Pediments, or shallow bedrock, Twenty wells were measured along the San Pedro River at ranches and farms north of Pomerene, from the rivers confluence 5 0 5 STATUTE MILES sheets. exist in places beneath the alluvial fill along the mountain fronts (Heindl, 1952, p.70). with Tres Alamos Wash to the Narrows. Conditions at these wells ranged from essentially no change to a maximum rise of 11.1 feet, with an average rise of 4.7 feet. Just south of the Narrows, seven measured wells showed changes ranging from a rise of Gettings, M.E., and Houser, B.B., 2000, Depth to Bedrock in the Upper San Pedro Valley, Cochise County, Southeastern Within the elongated trough of basin fill are three deeper troughs with depths of up to 6000 feet below land surface (Drewes,1980, 0.1 foot to a decline of 5.3 feet, with an average decline of 1.5 feet. The wells measured in this area are largely shallow wells Arizona. USGS Open File Report 00-1 38, 29 p., 8 plates. Gettings and Houser, 2000). Gettings and Houser (2000) found three deeper pockets of alluvium in the basin. One lies south used for irrigation and stock purposes. Irrigation has continued in the area where modest decline was noted. However, where LEGEND - EXPLANATION of Sierra Vista and west of the San Pedro River, a second lies under and north of the Babocomari River and west of the San water level rises were recorded, irrigation pumpage has decreased since 1990. Graf, Charles, 1999, Hydrogeology of Kartchner Caverns State Park, Arizona: as published by the National Speleological Pedro River, and a third lies northwest of Tombstone. Gettings and Houser (2000) also describe a more shallow area of Society for Journal of Cave and Karst Studies. hardrock extending eastward from the Huachuca Mountains, under Sierra Vista toward the San Pedro River. Bedrock is found Benson- Pomerene 124 WELL IN WHICH DEPTH TO WATER WAS MEASURED IN 2001 -2002 - - UPPER NUMBER, 124, IS DEPTH TO WATER IN FEET at relatively shallow depths of 200-500 feet below land surface along this line. This study also found that much of the southern In the Benson-Pomerene area, wells completed in both the shallow aquifer and the deeper (artesian) regional aquifer are Heindl, L. A., 1952, Upper San Pedro basin, Cochise County, in Groundwater in the basin and adjacent areas, BELOW LAND SURFACE. LOWER NUMBER, 4022, IS THE ALTITUDE OF THE WATER LEVEL IN FEET ABOVE MEAN SEA LEVEL. area of the basin under the San Pedro River and to the east of the river was underlain by very shallow alluvium (on the order common, however a majority of the wells in Pomerene are shallow. Sixteen flowing wells were observed in the Benson- Arizona—a summary, by L. C. Halpenny and others: U. S. Geological Survey Open-file Report, p. 69-86. 4022 DATUM IS REFERENCED TO THE NATIONAL VERTICAL GEODETIC DATUM OF 1929. of 150 to 500 feet). This study is notable because it defines the bedrock as much more shallow than prior studies had indicated, Pomerene area. Modest water level declines were recorded in both aquifers. In the shallow aquifer water level changes range effectively reducing the aquifers estimated total groundwater storage volume. from a rise of 0.5 feet to a decline of 10.2 feet, however most declines are in the 1.0 to 5.0 foot range. Most of the deep wells Konieczki, A. D., 1980, Maps Showing Groundwater Conditions in the Upper San Pedro Basin Area, Pima, Santa Cruz and ALLUVIAL-FILL DEPOSITS (CONSISTS OF SILT, SAND, CLAY, GRAVEL, AND CONGLOMERATE) are south of Pomerene in the Benson area. Changes in these wells range from a maximum rise of 0.3 feet to a maximum decline Cochise Counties, Arizona—i 978: U.S. Geological Survey Open-file Report 80-1192,2 sheets. Unconformably overlying the bedrock is the Pantano (?) Formation. The Pantano (?) Formation is a sedimentary deposit, of 18.9 feet, with most declines in the 4.0 to 9.0 foot range. which has been firmly established as Tertiary, and likely as Miocene in age. This unit is a poorly to moderately indurated Lee, W. T., 1905, Notes on the underground water of the San Pedro Valley, Arizona, Third annual report of the Reclamation HARDROCK GRANITIC, METAMORPHIC, VOLCANIC OR CONSOLIDATED SEDIMENTARY ROCK - WATER MAY OCCUR IN WEATHERED conglomerate, with clasts ranging in size from pebbles to boulders. They are composed of granite, limestone and volcanics, From west of Benson to the western Upper San Pedro Basin boundary, water level declines in the 5.0 to 7.0 foot range are Service, 1903-04: U. 5. 58th Cong., 3rd sess., H. Doc. 28, 2nd. ed., p. 165-1 70. OR FRACTURED ZONES, JOINT SYSTEMS, OR FLUVIAL DEPOSITS OVERLYING BEDROCK. embedded in a coarse sandstone matrix (Brown and others, 1966, p. 9-13). Gettings and Houser (2000), indicate that the common, with a maximum recorded decline of 11 feet. These are predominantly domestic and stock wells. Higher rates of Pantano (?) Formation probably exceeds 1,000 feet in thickness in some areas near Sierra Vista and Fort Huachuca. groundwater decline are found in Township 17S, Range 19E. This area contains wells that supply the Town of Benson and Littin, G. R., 1987, Ground-water resources of the Bisbee-Naco area, Cochise, County, Arizona: U. S. Geological Survey BOUNDARY BETWEEN HARDROCK AND ALLUVIUM Unconformably overlying the Pantano (?) Formation are the Quaternary and Tertiary (Pliocene) basin-fill deposits. The basin- development associated with nearby Kartchner Caverns State Park. Water-Resources Investigations Report 87-4103, 34 p. fill deposits, unlike the Pantano (?) Formation, are post Basin and Range development (Brown and others, 1966, p.15). The lower unit of the basin fill consists of whitish-gray to light-brown lenticular beds of strongly to weakly cemented gravel, St. David-Land 4000 WATER LEVEL CONTOURS - SHOWS THE APPROXIMATE ALTITUDE OF THE WATER-LEVEL. THE NUMBER 4000 REPRESENTS 4000 Meinzer, 0. E., Kelton, F. C., Forbes, R. H., 1913, Geology and water resources of Sulphur Spring Valley, Arizona, with a FEET ABOVE MEAN SEA LEVEL. DASHED WHERE INFERRED. sandstone, siltstone and clay. The lower unit can be up to 1,000 feet thick in places, near the center of the basin. The unit grades The St. David-Land area has a great number of wells completed in both the shallow aquifer and the deeper regional (artesian) section on Agriculture: U. S. Geological Survey Water-Supply Paper 320, 231 p. into coarse-grained beds a few feet thick near the mountain fronts (Roeske and Werrell, 1973, p. 10-11). aquifer. Water level changes ranging from a maximum decline of 11.1 feet to a maximum rise of 11.0 feet were observed, and GENERAL GROUNDWATER FLOW DIRECTION many wells continue to flow. Hydrograph (C) shows that the regional aquifer has undergone gentle rise since the 1990 mea- Meinzer, O. E., 1923, Outline of ground-water hydrology: U. S. Geological Survey Water Supply Paper 494, 71p. The upper unit of the basin fill is characterized by weakly cemented, sometimes compacted beds of reddish-brown to brown surement. The greatest changes have occurred in the shallow aquifer where the 11.1 foot decline was observed. In the area BOUNDARY OF UPPER SAN PEDRO BASIN sediments of gravel, sandstone, siltstone and clays. The unit tends to be well-bedded silt, sandy-silt and clays in the center of the south of St. David, declines in the range of less than 1.0 foot per year are found in the shallow aquifer, which is recharged by the Oppenheimer, J., Sumner, J. 5., 1980, Gravity modeling of the alluvial basins, southern Arizona: unpublished Master’s valley and grading into clayey-silty gravel near the mountain fronts. This unit may be as much as 800 feet thick (Roeske and river. The recent drought conditions have kept river flow at a minimum, thereby limiting recharge to the shallow aquifer and thesis, University of Arizona, Map. Werrell, 1973, p.11). This unit can form steep slopes where capped by well-cemented terrace deposits, but erodes into badlands contributing to the observed declines. The least amount of change was found in wells completed in the regional aquifer. Several wells reflect a rise in water level. FOR READERS WHO PREFER TO USE METRIC UNITS RATHER THAN INCH-FEET UNITS, topography if not protected by the terrace deposits (Brown and others, 1966, p. 16). In 1902, W.P. Blake noted that in the area Pool, D. R., Coes, A. L., 1999, Hydrologic investigations of the Sierra Vista subwatershead of the Upper San Pedro Basin, THE CONVERSION FACTORS FOR THE TERMS USED IN THIS REPORT ARE LISTED BELOW: of Benson on both sides of the San Pedro Valley, there are unconsolidated red clays and sediments in horizontal beds of great Cochise, County, Southeast Arizona: U. S. Geological Survey Water-Resources Investigations Report 99-4197, thickness, often terraced by river erosion, and extending high up on both sides of the bordering mountains (Meinzer and Sierra Vista-Huachuca City-Nicksville 41 p., 3 plates. Kelton, 1913, p.60). Water level declines in this area have been noted for decades. Water levels have continued to decline in the 11 years since 1990. ENGLISH UNITS METRIC UNITS Well measurements in and around Sierra Vista reveal declines for the 1990-Dec.2001-Jan.2002 period ranging from 1.2 feet to Putman, F., Mitchell, K., Bushner, G., 1988, Water resources of the upper San Pedro basin, Arizona: Arizona Department of In places, the basin-fill deposits are overlain by the beds of the flood-plain alluvium. They are unconsolidated, lenticular, river- a maximum of 14.8 feet in a public supply well for Sierra Vista. This well has declined an average of 1.4 feet per year for the last Water Resources, unpublished report, 158 p. 1 INCH 25.4 MILLIMETERS and stream-laid deposits of gravel, sand and silt. These beds are found along the channels and flood plain of the San Pedro 11 years. Most of the wells in this area of the cone are declining at a rate of less than 1 foot per year however. These findings are 1 FOOT 0.3048 METERS River and major tributaries, and range from less than a mile up to two miles in width, and from 40 to150 feet in thickness. Pool consistent with previous decline rates. Hydrographs K,L,M and O show the steady decline in the water table in the area of the Roeske, R. H., Werrell, W. L., 1973, Hydrologic conditions in the San Pedro River Valley, Arizona, 1971: Arizona Water 1 MILE 1.609 KILOMETERS and Coes (1999), suggest that the thickness is better defined in the Sierra Vista subwatershed as within the upper 15 meters cone of depression. Well (D-21-20) 33ACC, which had previously exhibited the largest decline (42.2 feet from 1958-1990, or Commission Bulletin 4, 76 p., 1 sheet. 1 SQUARE MILE 2.59 SQUARE KILOMETERS (approx 50 feet), of the surface. an average of 1.3 feet per year), declined a total of only 1.2 feet since 1990. Sellers, W. D., Hill, R. H., Sanderson-Rae, M., 1985, Arizona climate, the first hundred years, 1885-1985: Institute of Atmospheric Physics, University of Arizona, 143 p.

BASE MAP FROM U.S. GEOLOGICAL SURVEY THESE HYDROLOGIC MAPS ARE AVAILABLE UPON REQUEST FROM THE ARIZONA DEPARTMENT OF WATER RESOURCES, 1:250,000 TUCSON (1977), NOGALES (1969), AND DOUGLAS (1959) ADWR BOOKSTORE MAPS SHOWING GROUNDWATER CONDITIONS IN THE UPPER SAN PEDRO BASIN, INFORMATION CENTRAL, 500 NORTH THIRD STREET, PHOENIX, ARIZONA, 85004. THE HYDROLOGIC DATA ON WHICH THESE Phone: (602) 417-2485 MAPS ARE BASED ARE AVAILABLE AT THE ADWR BOOKSTORE. 602 417-2485 Fax: (602) 417-2488 WEBSITE: www.adwr.state.az.us COCHISE, GRAHAM AND SANTA CRUZ COUNTIES, ARIZONA—DEC. 2001- JAN. 2002 BY R.L. BARNES & F. PUTMAN D.W.R HYDROLOGIC MAP SERIES REPORT NO. 34 PREPARED IN COOPERATION WITH THE UNITED STATES GEOLOGICAL SURVEY THE ARIZONA DEPARTMENT OF WATER RESOURCES CHANGES IN WATER LEVEL AND HYDROGRAPHS OF SELECTED WELLS SHEET 2 OF 2

114 113 112 111 110 109 T R 21 E 11 37 37 S LEGEND - EXPLANATION

+10 WELL IN WHICH WATER LEVEL WAS MEASURED IN DEC., 2001- JAN 2002 - - Number, +10, is the difference, in feet, between Dec.1990 and R 22 E Dec. 2001-Jan. 2002 36 36

T A WELL IN WHICH A HYDROGRAPH DEPICTING CHANGES IN DEPTH TO WATER IS SHOWN COCONINO N 12 S ALLUVIAL-FILL DEPOSITS (CONSISTS OF SILT, SAND, CLAY, GRAVEL, AND CONGLOMERATE) Flagstaff KINGMAN

W E APACHE 2 HARDROCK GRANITIC, METAMORPHIC, VOLCANIC OR CONSOLIDATED SEDIMENTARY ROCK - WATER MAY OCCUR IN WEATHERED NAVAJO 0 35 35 S OR FRACTURED ZONES, JOINT SYSTEMS, OR FLUVIAL DEPOSITS OVERLYING BEDROCK. MOHAVE Holbrook YAVAPAI 0 BOUNDARY BETWEEN HARDROCK AND ALLUVIUM T 2 Prescott 13 0 0 WATER LEVEL CHANGE CONTOURS - REPRESENTS THE APPROXIMATE LINE OF EQUAL CHANGE IN WATER LEVEL, S to Dec. 2001-Jan. 2002. CONTOUR INTERVAL IS 5 FOOT. DASHED WHERE INFERRED. 0 34 34 BOUNDARY OF UPPER SAN PEDRO BASIN LA PAZ GILA PHOENIX

A FOR READERS WHO PREFER TO USE METRIC UNITS RATHER THAN INCH-FEET UNITS, THE CONVERSION -1 FACTORS FOR THE TERMS USED IN THIS REPORT ARE LISTED BELOW: MARICOPA T 33 33 YUMA 14 PINAL GRAHAM S ENGLISH UNITS METRIC UNITS GREENLEE -4 B 1 INCH 25.4 MILLIMETERS Yuma 1 FOOT 0.3048 METERS TUCSON 1 MILE 1.609 KILOMETERS 1 SQUARE MILE 2.59 SQUARE KILOMETERS R 18 E R 19 E PIMA R 20 E 32 32

-2 COCHISE 0 0 114 T SANTA 0 113 CRUZ -1 15 0 Nogales S -5 7 SCALE BARS 112 -11 2 -19 7 1 111 110 109 5 5 0 5 STATUTE MILES

5 4 0 1 6 11 10 4 7 8 6 0 50 100 MILES 5 8 4 2 7 9 5 0 510KILOMETERS -3 11 4 T -6 6 -12 18 0 50 100 150 KILOMETERS 16 -3 S 0 -2 INDEX MAP SHOWING AREA R 23 E TRANSVERSE MERCATOR PROJECTION OF REPORT (SHADED) -1 3 -1 -5 0 -4 -4 -3 BLACK NUMBERED LINES INDICATE THE 10,000 METER UNIVERSAL TRANSVERSE MERCATOR -4 -5 -7 -15 -3 GRID, ZONE 12 1977 MAGNETIC DECLINATION FROM TRUE NORTH VARIES FROM 13DEGREES -6 -10 -10 -6 -3 -19 (230 MILS) EASTERLY FOR THE CENTER OF THE WEST EDGE TO 121/2 (220 MILS) EASTERLY -2 -7 -6 -4 -2 FOR THE CENTER OF THE EAST EDGE -7 -3 -6 -6 -4 -7 -1 0 -2 1 -11 -5 T -7 -7 -6 -3 -6 1 -10 -11 -4 17 -2 -10 -4 -1 -10 C -4 S -9 -10 2 -2 5 -5 -1 -11 8 0 -1 0 -4 HYDROGRAPHS OF THE WATER LEVEL IN SELECTED WELLS SHOWN ON THE MAP 6 -9 D -4 -3 4 F -3 E -5 -5 -1 4 (Dashed line indicates an inferred water level) 9 5 -2 3 -18 5 11 T -3 10 -1 STOCK WELL STOCK WELL STOCK/DOMESTIC WELL STOCK WELL 18 0 1 0 A DEPTH: 415 ft. (D-14-21) 11BBC B DEPTH: 396 ft. (D-14-22) 34BDC C DEPTH: 520 ft. (D-17-21) 32BAB D DEPTH: 350 ft. (D-18-20) 06BDD S -1 -1 -1 250 250 0 200 0 -4

-1 -1 3 G 5 -7 0 450 450 200 400 1 T 0 1960 1970 1980 1990 2000 1960 1970 1980 1990 2000 1960 1970 1980 1990 2000 1960 1970 1980 1990 2000 19 2

S -1 3 -12 -1 -3 H DOMESTIC WELL STOCK WELL STOCK WELL STOCK WELL -4 2 -1 E DEPTH: 60 ft. (D-18-21) 06AAB2 F DEPTH: 396 ft. (D-18-21) 01DCA G DEPTH: 253 ft. (D-19-21) 12DBB2 H DEPTH: UNKNOWN (D-19-23) 35ACD -3 -5 -3 -14 -13 1 0 200 100 200 21 -5 -2 I -1 -2 5 -5 -1 -23 -5 -1 -3 -10 -4 -10 T -13 -2 -1 20 -5 -3 -4 -3 200 400 300 400 S -3 0 -1 1960 1970 1980 1990 2000 1960 1970 1980 1990 2000 1960 1970 1980 1990 2000 1960 1970 1980 1990 2000

-1 -3 -4 -1 0 STOCK WELL UNUSED WELL DOMESTIC WELL PUBLIC SUPPLY WELL L (D-21-20) 35DBB 7 -5 -5 3 I DEPTH: 300 ft. (D-20-20) 02DDD J DEPTH: 807 ft. (D-21-20) 16AAC1 K DEPTH: 700 ft. (D-21-20) 34DCC1 DEPTH: 722 ft.

0 200 400 350 0 1 -2 4 -7 J 11 -1 -4 -6 -8 -6 -6 N 0 T -6 -7 -6 1 -11 -3 -5 15 21 0 1 -11 0 -6 L -8 -6 0 S -10 -11 4 200 400 600 550 -4 9 -4 -1 -6 -1 -11 -3 1960 1970 1980 1990 2000 1960 1970 1980 1990 2000 1960 1970 1980 1990 2000 1960 1970 1980 1990 2000 -8 M -3 -3 -12 -1 0 1 K -15 -9 Q -3 -7 O -2 -2 -2 -15 -8 -2 -3 0 PUBLIC SUPPLY WELL STOCK/DOMESTIC WELL PUBLIC SUPPLY WELL DOMESTIC WELL -2 -3 -14 -11 1 M DEPTH: 620 ft. (D-21-21) 31BDC N DEPTH: 130 ft. (D-21-21) 22DDC O DEPTH: 710 ft. (D-22-20) 01BBD P DEPTH: 180 ft. (D-22-21) 23CBA T -5 -5 -14 -3 1 1 175 0 250 0 22 -1 -1 -4 -5 -3 -35 P S -1 -4 -20 -35 -6 -9 -10

15 -5 -4 5 BELOW LAND SURFACE IN FEET WATER TO DEPTH 14 0 -3 17 0 -2 -4 375 200 450 200 -6 6 -20 1960 1960 1960 -4 1960 1970 1980 1990 2000 1970 1980 1990 2000 1970 1980 1990 2000 1970 1980 1990 2000 -4 8 R 3 3 1 -30 -3 -2 R 24 E 1 1 0 -4 0 T -5 -26 0 2 1 2 UNUSED WELL UNUSED WELL UNUSED WELL STOCK/DOMESTIC WELL 23 -1 1 7 T 2 0 Q DEPTH: 715 ft. (D-22-22) 06DAC R DEPTH: UNKNOWN (D-23-22) 18BBB S DEPTH: 91.5 ft. (D-23-22) 33DCD2 DEPTH: 520 ft. (D-24-23) 06AAA1 S -5 -2 -2 2 0 0 0 100 -2 -1 -1 T 1 -2 0 -4 S -4 1 0 0 1 -32 1 1 -25 1 1 -2 -4 0 0 -2 -15 -20-28 -1 -30 0 -23 -16 -1 0 -10 T -2 -21 -27 -28 200 200 200 300 0 -4

5 -8 12

-1 -1

0 24 0 -16 1960 1970 1980 1990 2000 1960 1970 1980 1990 2000 1960 1970 1980 1990 2000 1960 1970 1980 1990 2000 -5 S -4 51 -1 -10 -20 -22 -23 -25 -24 -25

BASE MAP FROM U.S. GEOLOGICAL SURVEY THESE HYDROLOGIC MAPS ARE AVAILABLE UPON REQUEST FROM THE ARIZONA DEPARTMENT OF WATER RESOURCES, ADWR BOOKSTORE 1:250,000 TUCSON (1977), NOGALES (1969), AND DOUGLAS (1959) INFORMATION CENTRAL, 500 NORTH THIRD STREET, PHOENIX, ARIZONA, 85004. THE HYDROLOGIC DATA ON WHICH THESE Phone: (602) 417-2485 MAPS SHOWING GROUNDWATER CONDITIONS IN THE UPPER SAN PEDRO BASIN, MAPS ARE BASED ARE AVAILABLE AT THE ADWR BOOKSTORE. 602 417 2485 Fax: (602) 417-2488 WEBSITE: www.adwr.state.az.us COCHISE, GRAHAM AND SANTA CRUZ COUNTIES, ARIZONA—DEC 2001-JAN 2002 BY R.L. BARNES & F. PUTMAN