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Hydrogeology and water chemistry of Montezuma Well in Montezuma Castle National Monument and surrounding area, Arizona

Increasing population and associated residential and commercial development have greatly increased water use and consumption in the Verde Valley near Montezuma Well, a unit of Montezuma Castle National Monument in central Arizona. Flow from Montezuma Well and water levels in eight wells that are measured annually do not indicate that the ground-water system has been affected by development. Additional data are needed to develop an adequate ground-water monitoring program so that future effects of development can be detected. Monitoring the ground-water system would detect changes in discharge from the Montezuma Well or changes in the ground-water system that might indicate a potential change of flow to the well. Water samples were collected, and field measurements of specific conductance, pH, temperature, and dissolved oxygen were made throughout the pond at Montezuma Well during an exploration in May 1991. The exploration included two fissures in the bottom of the pond that were filled with sand. The sand in the fissures was kept in suspension by water entering the pond. Water chemistry indicates that the ground water from the area is a mixed combination of calcium, magnesium, sodium, and bicarbonate type water. The analyses for 18O/16O and 2H/1H show that the water from the wells and springs in the area, including Montezuma Well, has been exposed to similar environmental conditions and could have had similar flow paths. The MODFLOW finite-difference ground-water model was used to develop an uncalibrated interpretive model to study possible mechanisms for discharge of water at Montezuma Well. The study presents the hypothesis that ground water in the Supai Formation is the source of discharge to Montezuma Well because of the differences between the surface elevation of the pond at Montezuma Well and the stage in the adjacent Wet Beaver Creek. A series of simulations shows that upward flow from the Supai Formation is a possible mechanism for discharge to Montezuma Well, and that a geologic structure in the Supai Formation could play a role in the upward movement of water to Montezuma Well. The mechanism for inflow from the Verde Formation is not understood; however, this study concludes that the Verde Formation, Supai Formation, and other underlying rock units are probably the sources of water to Montezuma Well.

Water-Resources Investigations Report

Public water supplies in western Texas

This report gives a summarized description of the public water supplies in a region comprising 81 counties of western Texas and lying generally west of the hundredth meridian. It is the fourth and last of this series of reports concerning the public water supplies of the State. It gives the available data for each of 142 communities, as follows: The population of the community; the name of the official from whom the information was obtained; the ownership of the waterworks, whether private or municipal; the source of supply, whether ground water or surface water; the amount of water consumed; the facilities for storage; the number of customers served; the character of the chemical and sanitary treatment of the water, if any; and the chemical analyses of the water. Where ground water is used the following also are given. Records of wells, including drillers' logs; character of the pumping equipment; and yield of the wells and water-level records where they are available. Of the 142 public supplies, 133 are obtained from ground water, 5 from surface water, and 4 from a combination of both. The total amount of water . used for public supply in the region averages about 78,000,000 gallons a day. Of this about 61,000,000 gallons a day is ground water and about 17,000,000 gallons a day is surface water. The ground-water resources of the region from which public water supplies are drawn are in rocks that range in age from Permian to Quaternary. The Ogallala formation of Tertiary age (Pliocene), which covers about 35,000 square miles of the High Plains in Texas, is the most important ground-water reservoir in the region. The formation furnishes water for 78 public supplies and for irrigating about 1,000,000 acres of land. The amount of water used for irrigating amounted to about 1,000,000 acre-feet in 1948. The Trinity and Fredericksburg groups of Lower Cretaceous age supply ground water in the western part of the Edwards Plateau, which constitutes an area of more than 22,000 square miles. These formations furnish small to large supplies to 20 municipalities. Sands of the Dockum group of Triassic refurnish meager to moderate supplies of water for 10 municipalities in areas east of the southern part of the High Plains and in the northern Pecos Valley in Texas. Local alluvial, bolson, or volcanic deposits furnish ground water in small to large amounts in scattered localities in the remainder of the region. The Permian rocks are of little importance as a source of ground water for public supply, owing to the highly mineralized water in them. The results of the chemical analyses of 206 samples of water obtained from the public supplies of the region are given in this report. The analyses are reported in parts per million and in equivalents per million for those ions entering into ionic balance. Of the samples analyzed 57 percent contained silica in excess of 20 parts per million; about 9 percent contained iron in excess of 0.3 part per million; 78 percent had hardness in excess of 200 parts per million; about 18 percent contained sulfate in excess of 250 parts per million; 10 percent contained chloride in excess of 250 parts per million; 3 percent contained nitrate in excess of 20 parts per million; 37 percent contained fluoride in excess of 2 parts per million; and 12 percent contained dissolved solids in excess of 1,000 parts per million.

Water Supply Paper

Geology and ground-water resources of the lower Little Bighorn River Valley, Big Horn County, Montana, with special reference to the drainage of waterlogged lands

The lower Little Bighorn River valley, Montana, is in the unglaciated part of the Missouri Plateau section of the Great Plains physiographic province. The river and its principal tributaries rise in the Bighorn Mountains, and the confluence of this northward-flowing stream with the Bighorn River is near the east edge of Hardin, Mont. The normal annual precipitation ranges from about 12 inches in the northern part of the area to 15 inches in the southern part. The economy of the area is founded principally on farming, much of the low-lying land adjacent to the river being irrigated. The irrigated land is within the Crow Indian Reservation, although a part is privately owned. The bedrock formations exposed in the area are of Cretaceous age and include the Parkman sandstone, Claggett shale, Eagle sandstone, Telegraph Creek shale, and Cody shale. The Cloverly formation, Tensleep sandstone, and Madison limestone, which underlie but are not exposed in the area, and the Parkman sandstone in the southern half of the area appear to be the principal bedrock aquifers. All except the Parkman lie at depths ranging from a few feet to several thousand feet, and all appear to be capable of yielding water in commercial quantities. Some of the other formations arc capable of yielding enough water for domestic and stock needs. The river alluvium of Recent age and the Pleistocene terrace deposits are the principal unconsolidated formations in the area with respect to water supply and drainage. Wells yielding as much as 100 gallons per minute may be developed in favorable areas. Pumping tests reveal that the transmissibility of the coarser unconsolidated materials probably ranges from about 15,000 to 30,000 gallons per day per foot. Two tests of the Parkman sandstone showed transmissibilities of 6,000 and 20,000 gallons per day per foot. Although a test of the Cloverly formation showed a transmissibility of only 3,000 gallons per day per foot, the high artesian pressure--80 pounds per square inch at the land surface--in the Cloverly caused the tested well to yield about 200 gallons per minute by natural flow; this is greater than the yield of any other single well in the area. Textural properties were compared with the hydraulic properties determined by laboratory tests to show the relation between different types of waterbearing materials. Materials classified as heavy soils-normally somewhat dense and impervious-had an average permeability of 7.2 gallons per day per square foot, which was more than expected. One sample of very coarse alluvial material had a permeability of 6,000 gallons per day per square foot. The depth to water beneath irrigation units was mapped, thus showing the waterlogged areas. Waterlogging is not a serious problem where the water table is more than 6 feet below the land surface. For the drainage studies the unconsolidated deposits are classified in two zones-coarse-grained sediments resting on the relatively impermeable bedrock floor and overlying fine-grained sediments which extend to the land surface. The transmissibility of the coarse-sediment zone generally is many times greater than that of the fine-sediment zone. Because in many places drains could not be economically dug deep enough to enter the coarse zone, the study of the effectiveness of drainage completed in the fine zone received much attention. The studies showed that, despite a considerable thickness of fine-grained sediments between the bottom of the drain and the top of the coarse zone, drainage ditches frequently were effective in relieving waterlogging of fields nearby. Pilot relief wells installed in existing drains showed that the effectiveness of some drains could be increased appreciably by installing a series of relief wells. Records of fluctuations of water levels in 196 observation wells and water-level contour maps were studied to show the principal areas of recharge and discharge in the irrigable areas.

Montana

Geologic features and ground-water storage capacity of the Sacramento Valley, California

The Sacramento Valley constitutes the northern and smaller arm of the Central Valley of California. It is about 150 miles long by about 30 miles wide; and its area is about 5,000 square miles. The Sacramento Valley is drained by the Sacramento River, the largest in California, which rises west of Mount Shasta and flows southward to join the San Joaquin River near Suisun Bay and discharges through San Francisco Bay to the Pacific. Most of the valley floor is suitable for growing crops, and under irrigation the land is highly productive. The Sacramento Valley is underlain by sediments transported from the surrounding mountains by the Sacramento River and its tributaries. The floor of the valley slopes southward from about 300 feet above sea level at the north end near Red Bluff to sea level at Suisun Bay. The Sutter Buttes, which are erosional remnants of an old volcano rise to 2,132 feet above sea level near the center of the valley. The valley floor is not a featureless plain but is characterized by various types of topography, which have been assigned to four principal groups: 1, low hills and dissected alluvial uplands; 2, low alluvial plains and fans; 3, flood plains and natural levees; and 4, flood basins; a fifth and relatively minor group consists of the tidal Islands of the Sacramento-San Joaquin Delta, which are south of the principal area of investigation. The rocks that underlie the Sacramento Valley and the bordering mountains range from crystalline rocks of Paleozoic and Mesozoic age to unconsolidated alluvium of Recent age. These rocks have been subdivided into 20 geologic units which may be assigned to 2 broad categories: rocks that yield little water and rocks that yield water freely. The rocks of the first category are chiefly marine sedimentary rocks of Late Jurassic, Cretaceous, and Early Tertiary age and a basement complex of pre-Tertiary crystalline rocks. The rocks of the second category consist predominantly of nonmarine valley-filling sediments of late Tertiary and Quaternary age, which constitute the principal ground-water reservoir in the Sacramento Valley. The rocks that yield little or no water includes the following geologic units: 1, Basement complex of the Sierra Nevada (pre-Tertiary); 2, Shasta series (Lower Cretaceous); 3, Chico formation (Upper Cretaceous); 4, Paleocene series; 5, Eocene series (in part, water yielding); 6, basalt (Tertiary); 7, sedimentary rocks of volcanic origin on the west side of the Sacramento Valley (Tertiary, in part water yielding) ; 8, intrusive rhyolite and andesite and vent tuff of the Sutter Buttes (Pliocene); and 9, tuff-breccia of the Sutter Buttes (Pliocene, in part water yielding). The rocks that yield water freely, comprises the following geologic units: 1, Volcanic rocks from the Sierra Nevada (Eocene to Pliocene; in part yield little or no water); 2, Tuscan formation (Pliocene; in part yield little or no water); 3, Tehama formation (Pliocene); 4, Tehama formation and related continental sediments, undifferentiated (Pliocene and Pleistocene); 5, Laguna formation and related continental sediments (Pliocene and Pleistocene); 6, fanglomerate from the Cascade Range (Pleistocene); 7, Red Bluff formation (Pleistocene); 8, Victor formation and related deposits (Pleistocene); 9, alluvial-fan deposits (Pleistocene and Recent); 10, river deposits (Recent); and 11, flood-basin deposits (Recent). The volcanic rocks from the Sierra Nevada consist chiefly of andesitic and rhyolitic detritus. Most of these volcanic rocks are fragmental and were deposited either as mudflows or by streams. Their permeability is extremely variable, the poorly consolidated sandstone and conglomerate strata locally yield water copiously to wells, but the interbedded fine-grained and cemented strata are virtually impermeable and act as confining layers. The Tuscan formation, which occurs in the northeastern part of the valley, consists of fragmental andesitic and basaltic mate

Water Supply Paper

Induced recharge of an artesian glacial-drift aquifer at Kalamazoo, Michigan

As part of a program for managing its ground-water supply, the city of Kalamazoo has constructed induced-recharge facilities at the sites of several of its well fields. To determine the benefits of induced recharge in a water-management program, the U.S. Geological Survey, in cooperation with the city, conducted a series of field experiments at a city well field (Station 9). The 12 production wells at the test site penetrate about 160 feet of glacial drift, which can be separated into three general units a lower aquifer, an intervening confining layer, and an upper aquifer. Although the upper aquifer is not tapped by any of the municipal supply wells, it serves as a storage and transmission medium for water from the West Fork Portage Creek. The testing program consisted of four aquifer and three recharge tests. The aquifer tests show that the transmissibility of the upper and lower aquifers ranges from 50,000 to 100,000 gallons per day per foot and indicate that nearly 200 gpm (gallons per minute) leaks through the intervening aquiclude under nonpumping conditions. The object of the three recharge tests (tests 5, 6, and 7) was to observe the effects of induced recharge by varying conditions in the recharge channel. During the three recharge tests, 7 wells were pumped at a total rate averaging about 2,500 gpm. During test 5, inflow to the channel was shut off, and the water level in the channel was allowed to decline. Drawdowns measured during this test were used as a standard for comparison with drawdowns in tests 6 and 7. During test 6, the head in the recharge channel was maintained as constant as possible, and the inflow to the channel was measured. The rate of induced recharge, as indicated by the measured inflow, averaged about 300 gpm. Between tests 6 and 7, the area of the channel was increased from 27,000 to 143,000 square feet. During test 7, the head in the channel was again maintained as constant as possible, but the inflow to the larger channel increased to about 600 gpm. The principal effect of induced recharge on the two aquifers was to reduce the amount and rate of drawdown. Therefore, where water levels and artesian pressures can be maintained at high stages, the result is lower pumping costs and increased rates of withdrawal during periods of peak demand.

Michigan

Artesian water in the Malabar coastal plain of southern Kerala, India

The present report is based on a geological and hydrological reconnaissance during 1954 of the Malabar Coastal Plain and adjacent island area of southern Kerala to evaluate the availability of ground water for coastal villages and municipalities and associated industries and the potentialities for future development. The work was done in cooperation with the Geological Survey of India and under the auspices of the U.S. Technical Cooperation Mission to India. The State of Kerala, which lies near the southern tip of India and along the eastern shore of the Caspian Sea, contains a total area of 14,937 square miles. The eastern part of the state is s rugged mountainous highland which attains altitudes of more than 6,000 feet. This highland descends westward through piedmont upland to s narrow coastal plain, which reaches a maximum width of about 16 miles in the latitude of Shertalli. A tropical monsoon rain-forest climate prevails in most of Kerala, and annual rainfall ranges from 65 to 130 inches in the southern part of the coastal plain to as much a 200 inches in the highland. The highland and piedmont upland tracts of Kerala are underlain by Precambrian meamorphic and igneous rocks belonging in large parabola-the so-called Charnockite Series. Beneath ahe coastal plain are semiconsolidated asunconsolidated sedimentary deposits whose age ranges from Miocene to Recent. These deposits include sofa sandstone and clay shale containing some marl or limestone and sand, and clay and pea containing some gravel. The sofa sandstone, sand, and gravel beds constitute important aquifers a depths ranging from a few tens of feet to 400 feet or more below the land surface. The shallow ground war is under water-able or unconfined conditions, but the deeper aquifers contain water under artesian pressure. Near the coast, drilled wells tapping the deeper aquifers commonly flow with artesian heads as much as 10 to 12 feet above the land surface. The draft from existing wells in the coastal belt between Quilon and Alleppy was estimated at 1 to 1 1/2 million imperial gallons a day. However, favorable conations exist for considerable further ground-water development in the coastal plain provided that sufficient attention is given to the potential hazards of saltwater encroachment and local overdevelopment. It is estimated that the overall potential for development of water from wells is probably at least several tens of millions of gallons a day, and perhaps more, in the Malabar Coastal Plain of southern Kera. Such a draft would have to be well dispersed to avoid overdevelopment and salt-war encroachment.

Water Supply Paper

Water in the Kahuku area, Oahu, Hawaii

The Kahuku area comprises the north end of the Koolau Range and its bordering coastal plain. This part of the range is less deeply eroded than oth3r parts, and except for long, narrow valleys and cliffs near the shore, it has retained the general shape of the original volcanic dome. A 21/2-mile-wide dike zone of parallel and subparallel dikes along the crest is the remnant of the fissure zone of eruption. Outcrops are mostly permeable lava flows of the Koolau Volcanic Series, which are intruded by dikes inside the dike zone and are free of dikes outside it. The lava flows constitute main aquifers, and water bodies in them are called dike water inside the dike zone and basal water outside it. Dikes, because they are less permeable than the lava flows they intrude, impound ground water, thereby controlling its movement, discharge, and storage. The top of the dike-impounded water is at an altitude of at least 1,000 feet near the south end of the Kahuku area. Dike water is discharged as leakage, the amount of which fluctuates in response to changes in storage, as flow into streams, where they intersect saturated rock, and as underflow to the basal-water body. Basal water occurs on either side of the dike zone, which forms both a structural and hydrologic boundary. It is artesian on the windward side wherever it underlies the coastal plain, and the altitude of water levels ranges from 7 to 22 feet. Leeward of the dike zone, basal water occurs only under water-table conditions because of the near absence of a coastal plain, and the altitude of water levels ranges from less than 1 foot to about 3 feet. The quality of dike water is excellent except near the north end. where it is slightly contaminated by infiltration of irrigation water that contains as much as 1,200 mg/1 (milligrams per liter) chloride. Irrigation water is also a source of contamination of the basal-water body. The major contaminant, however, is sea water, which underlies the basal-water body. In the Kahuku subarea--where pumpage from the basal-water body is greatest--sea-water contamination is a major concern. Natural contamination by encroaching sea water extends more than 2 miles inland in the Waimea-Kawela subarea and generally precludes development of large quantities of basal water. At low altitudes where the perennial flow is small, all streams are intermittent except Kaluanui and Kamananui. Some streams are perennial in their upper reaches because of persistent rainfall, and some are perennial in their middle reaches owing to the discharge of dike water; however, most flows are small in the lower reaches because most of the flow has infiltrated into the ground-water reservoir. For these reasons, streamflow cannot be economically developed and is not a reliable source of water supply. Average rainfall is about 240 mgd (million gallons per day). Of this amount, about 220 mgd is in the mountains. On .the basis of a rainfall input of 220 mgd and estimates of stream runoff and evapotranspiration, ground-water flow is estimated to be 85 mgd, a figure which compares favorably with estimates based on analyses of pumping-test data. Of this amount, an average of 30 mgd is discharged by wells and the remaining 55 mgd is eventually discharged to the sea by underflow or to the atmosphere by evapotranspiration. The most promising areas for developing basal water are in the Hauula and Laie subareas, where draft is low and ground-water flow is high. The Waimea-Kawela subarea is not promising owing 'to low ground-water flow even though draft is low. Least promising for development is in the Kahuku subarea where an overdeveloped condition prevails in which draft for sugarcane irrigation exceeds the ground-water flow. The development of dike water is promising in the Waimea-Kawela subarea where ground-water flow greatly exceeds the draft.

Water Supply Paper

Digital-simulation and projection of water-level declines in basalt aquifers of the Odessa-Lind area, east-central Washington

A digital computer program using finite-difference techniques simulates an intensively pumped, multilayered basalt-aquifer system near Odessa. The aquifers now developed are in the upper 1,000 feet of a regionally extensive series of southwesterly dipping basalt flows of the Columbia River Group. Most of the aquifers are confined. Those in the depth range of about 500 to 1,000 feet are the chief source of ground water pumped from irrigation wells. Transmissivity of these aquifers ranges from less than 2,700 feet squared per day to more than 40,000 feet squared per day, and storage coefficients range from 0.0015 to 0.006. Shallower aquifers are generally much less permeable, but they are a source of recharge to deeper aquifers with lower artesian heads; vertical leakage occurs along joints in the basalt and down uncased wells, which short circuit the aquifer system. For model analysis, the deeper, pumped aquifers were grouped and treated as a single layer with drawdown-dependent leakage from an overlying confining layer. Verification of the model was achieved primarily by closely matching observed pumpage-related head declines ranging from about 10 feet to more than 40 feet over the 4-year period from March 1967 to March 1971. Projected average annual rates of decline in the Odessa-Lind area during the 14-year period from March 1967 to March 1981 are: from 1 to 9 feet per year if pumpage is maintained at the 1970 rate of 117,000 acre-feet per year; or, from 3 to 33 feet per year if 1970 pumpage is increased to 233,000 acre-feet per year, which includes 116,000 acre-feet per year covered by water-right applications held in abeyance. In each case, projected drawdown on the northeast side of a major ground-water barrier is about double that on the southwest side because of differences in transmissivity and storage coefficient and in sources of recharge.

Washington

Quantitative assessment of the shallow ground-water flow system associated with Connetquot Brook, Long Island, New York

Streamflow on Long Island is derived principally from shallow ground water that flows above the deeper regional flow system. The movement of shallow ground water was studied during 1975-82 at Connetquot Brook, an undisturbed stream in Connetquot River State Park, in south-central Long Island, New York. The investigation encompassed (1) field studies of streamflow, ground-water levels, and age of water as indicated by tritium and dissolved-oxygen concentrations and (2) numerical simulation of the shallow flow system to evaluate the hydraulic factors that govern the direction of shallow ground-water flow near and beneath the stream. Analysis of water-level data indicates that ground water flows essentially horizontally throughout the drainage basin except near and beneath the stream, where it moves vertically upward toward the stream discharge boundary. Water levels in wells driven directly into the streambed and into the streambank at three sites were 1 to 2 feet higher than stream stage in the first 5 feet of penetration. Increases in head, which were detected to depths of 30 feet beneath the streambed, indicate upward movement of water above that depth. Hydraulic conductivity of the streambed sediments was calculated from head gradients in the streambed and from measured stream seepage; values were between 11 and 15 feet per day. Water samples from selected wells were analyzed for dissolved-oxygen and tritium concentrations to determine the relative age of the water in an attempt to locate the bottom boundary of the shallow flow system. Dissolved oxygen showed no pattern, but tritium concentrations about 1,000 feet from the stream were lower than those near the stream. The tritium concentrations indicate that the lower flow boundary was between 45 and 100 feet below the water table. A two-dimensional cross-sectional flow model of the shallow flow system was developed. The near-stream model response compared well with field data when the streambed discharge boundary was simulated as a uniform leaky bed. A systematic sensitivity analysis was done to determine which factors have the greatest influence on hydraulic head in the system. Ten dimensional parameters that describe the important aspects of the flow system were combined into a series of dimensionless parameters to simplify analysis. Results indicate that (1) streambed factors (width and hydraulic conductivity) are most influential upon heads near the stream, (2) factors representing thickness of the shallow flow system influence heads distant from the stream but have a negligible effect near the stream, and (3) factors that represent the quantity of water entering the system (recharge) influence the heads throughout the area. Field measurements of hydraulic head indicate that the thickness of the shallow flow system below the stream channel is about 30 feet. However, results of the sensitivity analysis indicate that the shallow system's thickness has a negligible effect on head distribution beneath the stream.

Water Supply Paper

Geology and water resources of Owens Valley, California

Owens Valley, a long, narrow valley located along the east flank of the Sierra Nevada in east-central California, is the main source of water for the city of Los Angeles. The city diverts most of the surface water in the valley into the Owens River-Los Angeles Aqueduct system, which transports the water more than 200 miles south to areas of distribution and use. Additionally, ground water is pumped or flows from wells to supplement the surface-water diversions to the river-aqueduct system. Pumpage from wells needed to supplement water export has increased since 1970, when a second aqueduct was put into service, and local concerns have been expressed that the increased pumpage may have had a detrimental effect on the environment and the indigenous alkaline scrub and meadow plant communities in the valley. The scrub and meadow communities depend on soil moisture derived from precipitation and the unconfined part of a multilayered aquifer system. This report, which describes the hydrogeology of the aquifer system and the water resources of the valley, is one in a series designed to (1) evaluate the effects that groundwater pumping has on scrub and meadow communities and (2) appraise alternative strategies to mitigate any adverse effects caused by, pumping. Two principal topographic features are the surface expression of the geologic framework--the high, prominent mountains on the east and west sides of the valley and the long, narrow intermountain valley floor. The mountains are composed of sedimentary, granitic, and metamorphic rocks, mantled in part by volcanic rocks as well as by glacial, talus, and fluvial deposits. The valley floor is underlain by valley fill that consists of unconsolidated to moderately consolidated alluvial fan, transition-zone, glacial and talus, and fluvial and lacustrine deposits. The valley fill also includes interlayered recent volcanic flows and pyroclastic rocks. The bedrock surface beneath the valley fill is a narrow, steep-sided graben that is structurally separated into the Bishop Basin to the north and the Owens Lake Basin to the south. These two structural basins are separated by (1) a bedrock high that is the upper bedrock block of an east-west normal fault, (2) a horst block of bedrock (the Poverty Hills), and (3) Quaternary basalt flows and cinder cones that intercalate and intrude the sedimentary deposits of the valley fill. The resulting structural separation of the basins allowed separate development of fluvial and lacustrine depositional systems in each basin. Nearly all the ground water in Owens Valley flows through and is stored in the saturated valley fill. The bedrock, which surrounds and underlies the valley fill, is virtually impermeable. Three hydrogeologic units compose the valley-fill aquifer system, a defined subdivision of the ground-water system, and a fourth represents the valley fill below the aquifer system and above the bedrock. The aquifer system is divided into horizontal hydrogeologic units on the basis of either (1) uniform hydrologic characteristics of a specific lithologic layer or (2) distribution of the vertical hydraulic head. Hydrogeologic unit 1 is the upper unit and represents the unconfined part of the system, hydrogeologic unit 2 represents the confining unit (or units), and hydrogeologic unit 3 represents the confined part of the aquifer system. Hydrogeologic unit 4 represents the deep part of the ground-water system and lies below the aquifer system. Hydrogeologic unit 4 transmits or stores much less water than hydrogeologic unit 3 and represents either a moderately consolidated valley fill or a geologic unit in the valley fill defined on the basis of geophysical data. Nearly all the recharge to the aquifer system is from infiltration of runoff from snowmelt and rainfall on the Sierra Nevada. In contrast, little recharge occurs to the system by runoff from the White and Inyo Mountains or from direct precipitation on the valley floor. Ground wat

Water Supply Paper

Numerical simulation of ground-water flow in the central part of the western San Joaquin Valley, California

The occurrence of selenium in agricultural drain water in the central part of the western San Joaquin Valley, California, has focused concern on strategies for managing shallow, saline ground water. To assess alternatives to agricultural drains, a three-dimensional, finite-difference numerical model of the regional groundwater flow system was developed. This report documents the mathematical approach used to model the flow system, the data base on which the model is based, and the methods used to calibrate the model. The 550-square-mile study area includes parts of the Panoche Creek alluvial fan and parts of the Little Panoche Creek and Cantua Creek alluvial fans. The model simulates transient flow in the semiconfined and confined zones above and below the Corcoran Clay Member of the Tulare Formation of Pleistocene age. The model incorporates areally distributed ground-water recharge, areally and vertically distributed pumping, regional-collector drains in the Wesdands Water District (operative from 1980 to 1985), on-farm drains in parts of the Panoche, Broadview, and Firebaugh Water Districts, and bare-soil evaporation (which occurs if the water table is within 7 feet of land surface). The model also incorporates texture-based estimates of hydraulic conductivity, where texture is defined as the fraction of coarse-grained deposits present in a given subsurface interval. The numerical model was developed using hydrologic data from 1972 to 1988. Most of the parameters incorporated into the model were evaluated independently of the model, including system geometry, the distribution of texture, the altitudes of the water table and potentiometric surface of the confined zone in 1972 (initial condition), the hydraulic conductivity of coarse-grained deposits derived from the Coast Ranges, the hydraulic conductivity of coarse-grained deposits derived from the Sierra Nevada, specific storage, recharge, pumping, and parameters needed to incorporate drains and bare-soil evaporation. Four parameters were calibration variables: the hydraulic conductivity of fine-grained deposits in the semiconfined zone, the hydraulic conductivity of the Corcoran Clay Member, specific yield, and the transmissivity of the confined zone. The model was calibrated in two phases. In the first phase, a steady-state model of the ground-water flow system in 1984 was used to constrain the relation between the hydraulic conductivity of fine-grained deposits in the semiconfined zone and the hydraulic conductivity of the Corcoran Clay Member, thus reducing the number of independent variables from four to three. In the second phase of calibration, the change in altitude of the water table from 1972 to 1984, the change in altitude of the potentiometric surface of the confined zone from 1972 to 1984, and the number of model cells subject to bare-soil evaporation from 1972 to 1988 were used to evaluate the remaining three variables. The calibrated model reproduces the average change in water-table altitude (1972-84) to within 0.4 foot (average measured change 11.5 feet) and the average change in confined zone head (1972- 84) to within 19 feet (average measured change 120 feet). The simulated time-series record of the total number of model cells subject to bare-soil evaporation (each cell is 1 mile square) is within the range of the measured data. The measured values are at a minimum in October and a maximum in July. The October values ranged from 103 in 1972 to 132 in 1984 (the drains were closed in 1985) to 151 in 1988. The July values ranged from 144 in 1973 to 198 in 1984, to 204 in 1988. The simulated values ranged from 103 in 1972 to 161 in 1984, to 208 in 1988.

Water Supply Paper

Bedrock aquifers of eastern San Juan County, Utah

This study is one of a series of studies appraising the waterbearing properties of the Navajo Sandstone and associated formations in southern Utah. The stu<¥ area is al:x>dy area is about 4,600 square miles, extending from the Utah-Arizona State line northward to the San Juan-Grand County line and westward from the Utah-Colorado State line to the longitude of about 109°50'. Some of the water-yielding formations are grouped into aquifer systems. The C aquifer is comprised of the DeChelly Sandstone Member of the Cutler Formation. The P aquifer is comprised of the Cedar Mesa Member of the Cutler Formation and the undifferentiated Cutler Formation. The N aquifer is comprised of the sedimentary section that includes the Wingate Sandstone, Kayenta Formation, Navajo Sandstone, Carmel Formation, and Entrada sandstone. The M aquifer is comprised of the Bluff Sandstone Member and other sandstone units of the Morrison Formation. The D aquifer is comprised of the Burro Canyon Formation and Dakota Sandstone. Discharge from the ground-water reservoir to the San Juan River between gaging stations at Four Corners and Mexican Hat is about 66 cubic feet per second. The N aquifer is the main aquifer in the study area. Recharge by infiltration of precipitation is estimated to be 25,000 acre-feet per year. A major ground-water divide exists under the broad area east of Monticello. The thickness of the N aquifer, where the sedimentary section is fully preserved and saturated, generally is 750 to 1,250 feet. Hydraulic conductivity values obtained from aquifer tests range from 0.02 to 0.34 foot per day. The total volume of water in transient storage is about 11 million acre-feet. Well discharge somewhat exceeded 2,340 acre-feet during 1981. Discharge to the San Juan River from the N aquifer is estimated to be 6.9 cubic feet per second. Water quality ranges from a calcium bicarbonate to sodium chloride type water

Utah

Hydrologic reconnaissance of the southern Great Salt Lake Desert and summary of the hydrology of west-central Utah

This report is the last of 19 hydrologic reconnaissances of the basins in western Utah. The purposes of this series of studies are (1) to analyze available hydrologic data and describe the hydrologic system, (2) to evaluate existing and potential water-resources development, and (3) to identify additional studies that might be needed. Part 1 of this report gives an estimate of recharge and discharge, an estimate of the potential for water-resources development, and a statement on the quality of water in the southern Great Salt Lake Desert part of west-central Utah. Part 2 deals with the same aspects of west-central Utah as a whole. Part 2 also summarizes the evidence of interbasin ground-water flow in west-central Utah and presents a theory for the origin of the water discharged from Fish Springs.

Utah

Ground-water reconnaissance of the central Weber River area, Morgan and Summit Counties, Utah

During July 1978 to June 1980, the U.S. Geological Survey conducted a reconnaissance of ground-water conditions and ground- and surface-water relationships in the central Weber River area. This reconnaissance was done in cooperation with the Utah Department of Natural Resources, Division of Water Rights. The study area is a series of mountain valleys along the Weber River in the Wasatch Ranqe and between the Wasatch Range and the Uinta Mountains in north-central Utah (fig. 1). As defined for this study, the area includes the Weber River drainage from Hoytsville, just south of Coalville, to the western boundary of Morgan County at the western front of the Wasatch Range (pl. 1). The East Canyon Creek tributary drainage is included from the Weber River to the Morgan County-Summit County line. The study focused on the major valleys along and tributary to the Weber River with less emphasis on the upland tributary areas.

Utah

Hydrology and model of North Fork Solomon River Valley, Kirwin Dam to Waconda Lake, north-central Kansas

The alluvial valley of the North Fork Solomon River is an important agricultural area. Reservoir releases diverted below Kirwin Dam are the principal source of irrigation water. During the 1970'S, severe water shortages occurred in Kirwin Reservoir and other nearby reservoirs as a result of an extended drought. Some evidence indicates that surface-water shortages may have been the result of a change in the rainfall-runoff relationship. Examination of the rainfall-runoff relationship shows no apparent trend from 1951 to 1968, but annual records from 1969 to 1976 indicate that deficient rainfall occurred during 6 of the 8 years. Ground water from the alluvial aquifer underlying the river valley also is used extensively for irrigation. Utilization of ground water for irrigation greatly increased from about 200 acre-feet in 1955 to about 12,300 acre-feet in 1976. Part of the surface water diverted for irrigation has percolated downward into the aquifer raising the ground-water level. Ground-water storage in the aquifer increased from 230,000 acre-feet in 1946 to 275,000 acre-feet in 1976-77. A digital model was used to simulate the steady-state conditions in the aquifer prior to closure of Kirwin Dam. Model results indicated that precipitation was the major source of recharge to the aquifer. The effective recharge, or gain from precipitation minus evapotranspiration, was about 11,700 acre-feet per year. The major element of discharge from the aquifer was leakage to the river. The simulated net leakage (leakage to the river minus leakage from the river) was about 11,500 acre-feet per year. The simulated value is consistent with the estimated gain in base flow of the river within the area modeled. Measurements of seepage used to determine gain and loss to the stream were made twice during 1976. Based on these measurements and on base-flow periods identified from hydrographs, it was estimated that the ground-water discharge to the stream has increased about 4,000 acre-feet per year from 1946 to 1976. During the same period, ground water withdrawn from the aquifer increased 12,100 acre-feet per year. Hydrographs of water levels in wells indicate some withdrawal from aquifer storage during 1976, possibly as a combined result of below-normal rainfall and greatly increased pumpage. The analysis of data is inconclusive as to whether the aquifer can sustain increased groundwater development. However, the analysis does indicate that the aquifer could sustain withdrawals at the 1976 rate for several consecutive years of drought similar to the 1976 conditions.

Kansas

Annual water-level measurements in observation wells, 1951-1955, and atlas of maps showing changes in water levels for various periods from beginning of record through 1954, New Mexico

This report tabulates the annual measurements of water level in the observation wells in the various irrigated areas, primarily from 1951 through 1955. It summarizes changes in water level by discussion and with an atlas of nearly all the maps of change of water level for the period of record to 1955 for each area in which observations are being made. Included also are hydrographs for the period of record through 1954 of several selected wells in the various areas irrigated from ground-water sources. The annual measurements of water level before 1951, seasonal measurements, and daily records of water levels in wells equipped with recording gages have been published in an annual series of U. S. Geological Survey water-supply papers.

New Mexico

Sequence stratigraphic framework of upper pliocene to holocene sediments of the Los Angeles Basin, California: Implications for aquifer architecture

Executive Summary Groundwater provides more than one-third of the municipal water supply for the coastal Los Angeles Basin and defining the aquifer architecture is a high priority for ground-water managers. Sequence stratigraphy, the state-of-the-art method for delineating reservoir geometry and continuity in the petroleum industry, is now being incorporated into ground water resource assessments and environmental investigations. By evaluating subsurface data using sequence stratigraphy, the geometry and distribution of aquifer and aquitard sediments are linked to the original depositional processes that formed the sediments. Skyline Ridge, Inc., the U.S. Geological Survey (USGS), in cooperation with Los Angeles County Department of Public Works (LACDPW) and the Water Replenishment District of Southern California (WRDSC) completed an investigation of the Wilmington – Long Beach area by integrating data from new exploratory research boreholes, marine reflection seismic, vintage land reflection seismic, and high-resolution gravity measurements. Sequence stratigraphy is shown to define pathways for saltwater intrusion into freshwater coastal aquifers by integrating preexisting data with (1) the new borehole observations and (2) structural and physical properties data derived from the geophysical measurements. By constructing a series of seismic reflection and well log cross sections (presented as sheets), this investigation further defines and delineates ten sequences of Late Pliocene to Holocene age in the Wilmington – Long Beach area of the Los Angeles Basin. These sequences were first described by Ponti and others (2007), and the implications for sea water intrusion was discussed by Edwards and others (2009a). In addition, this investigation presents regional seismic facies – environment of deposition maps for the five youngest sequences: 1) the Dominquez Sequence; 2) the Mesa Sequence; 3) the Pacific Sequence; the Harbor Sequence; and 4) the Bent Spring Sequence. The stratigraphic framework established in the Wilmington – Long Beach area is extended into the Central Basin of the greater Los Angeles area by utilizing 1980s and older vintage petroleum exploration land seismic reflection data. Tying this data to the available groundwater monitoring well network in the Central and West Coast Basins demonstrate aquifer correlation problems, and may provide insights into establishing a more robust groundwater model for the greater Los Angeles Basin area.

Book

Geology and ground-water resources of the island of Hawaii

Hawaii, the largest island in the Hawaiian group, is 93 miles long, 76 miles wide, and covers 4,030 square miles. Mauna Loa Volcano is 13,680 feet high and Mauna Kea is 13,784 feet high. Plate 1 shows the geology, wells, springs, and water-development tunnels. Plate 2 is a map and description of points of geologic interest along the main highways. Plate 3 (same sheet as plate 2) shows highways and points of geologic interest in Hawaii National Park area. The volcanic terms used in the report are defined. Hawaii was built by five volcanoes. All the rocks are volcanic, except for minor amounts of sedimentary rock derived from them. Mauna Loa and Kilauea volcanoes erupt often; Hualalai Volcano last erupted in 1801; Mauna Kea has had Recent but no historic eruptions; Kohala Mountain has long been extinct. Kohala Mountain constitutes the northern end of the island. It is built largely of rocks of the Pololu volcanic series which are dominantly olivine basalt with a few thin intercalated beds of vitric basaltic ash. After the eruption of this series, Kohala Volcano was deeply eroded on the windward (northeastern) side, and a deep soil formed on its other slopes. Later, oligoclase andesite and trachyte lava flows, named the Hawi volcanic series, were erupted. They rest on soil at the top of the Pololu series, and lie in the valleys cut into the Pololu lavas on the windward slope. Both the Pololu and Hawi volcanics were erupted from three rift zones trending N. 35&deg; W., S. 65&deg; E., and S. 50&deg; W. from the summit of the mountain. The rift zones are marked at the surface by rows or cinder cones, and beneath the surface by innumerable dikes. A caldera occupied the summit of the mountain at the beginning of the eruption of the Hawi lavas, and for a time confined the flows. It was gradually filled and the lava escaped northeastward into the large valleys. Some of the caldera faults can still be traced. A shallow graben indents the summit now. South of Kohala Mountain lies the much larger volcano of Mauna Kea. The early rocks of Mauna Kea constitute the Hamakua volcanic series. The lower member of this series consists chiefly of olivine basalt flows with intercalated thin beds of vitric basaltic ash. The olivine basalt of the lower member changes gradationally into the upper member, in which basalt and olivine basalt arc still abundant, but andesite also is present. Lavas of the upper member interfinger with Hawi lavas of Kohala Mountain. The Hamakua volcanic series is mantled with Pahala ash 5 to 20 feet thick, above which lie the rocks of the Laupahoehoe volcanic series. Locally the two series are separated by erosional unconformity, The Laupahoehoe lavas are dominantly andesite. The andesites erupted after the last glacial epoch are mapped separately on plate 1. The Laupahoehoe volcanic series, and probably also the Hamakua volcanic series, were erupted principally from three rift zones, trending west, northeast and south-southeast from the summit of the mountain. The upper slopes are studded with many large cinder cones, lying principally along the rift zones. Late in its geologic history, Mauna Kea was capped by a small glacier, presumably contemporaneous with the Wisconsin stage of glaciation in North America, which left conspicuous terminal, lateral, and ground moraines. Deposits exposed in canyons on the southern slope, formerly believed to be of glacial origin, are now believed to be volcanic explosion breccias. The main bulk of Hualalai Volcano is built of basalts of the Hualalai volcanic series. One flow of andesite has been found. The cinder and spatter cones lie principally along three rift zones which trend northwest, north, and southeast from the summit. On the northern slope of Hualalai Volcano lies the large trachyte pumice cone of Puu Waawaa, and its thick flow of trachyte. These are grouped together as the Waawaa volcanics. They are partly buried by later basalts from both Hualalai and Mauna Loa. The last eruption of Hualalai Volcano, in 1800&ndash;1801, produced olivine basalt. The earliest exposed rocks of Mauna Loa comprise the Ninole volcanic series. Several beds of altered vitric ash are intercalated with the lavas. Following eruption of the Ninole series, a long period or quiescence occurred, during which deep amphitheater-headed valleys were cut. This was followed by the eruption of the Kahuku volcanic series, consisting mostly of lavas with some thin beds of ash. The Rahuku series is overlain by the Pahala ash, which overlies also the Hilina volcanic series on Kilauea, the Hamakua volcanic series on Mauna Kea, and the Hawi volcanic series on Kohala, providing a rough datum for correlation of the lavas of the four mountains. Deposition of the Pahala ash was followed on Mauna Loa by eruption of the Kau volcanic series, which has continued until the present time. The historic and flaws of the Kau series are mapped separately on plate 1. The historic eruptions and volcanic activity of Mauna Loa are briefly described. The western and southern slopes of Mauna Loa are cut by normal faults along which the lower flanks of the mountain have slipped seaward. The Kau volcanic series and presumably also the Kahuku and Ninole volcanic series were erupted principally from vents along two rift zones which extend northeast and southwest from the summit caldera. The lavas of all three series are preponderantly olivine basalt. Many of the lavas contain small amounts of hypersthene. The Pahala ash on the northeastern and eastern slopes of Mauna Loa was derived largely from Mauna Kea. West and south of Kilauea Caldera, however, it was derived principally from Kilauea. Minor amounts were contributed by eruptions of Mauna Loa. It is a vitric basaltic ash, now generally altered to palagonite. The earliest exposed lavas and thin intercalated ash beds of Kilauea Volcano comprise the Hilina volcanic series. These are capped by the Pahala ash, which in turn, is overlain by the lavas and thin ash beds of the Puna volcanic series. The volcanics of both series were erupted along two rift zones, one extending southwestward from Kilauea Caldera, and the other extending southeastward for 5 miles and then bending sharply east by north. The lavas of both series are very largely olivine basalt. A few flows contain hypersthene. Augite phenocrysts are common in Mauna Loa lavas, but rare in those of Kilauea, indicating that crystallization has not progressed as far in the magma chamber of Kilauea Volcano as in that of Mauna Loa. Eruption of the Puna volcanic series has continued until the present time, the historic flows being separated from the prehistoric ones on plate 1. The historic eruptions and volcanic activity of Kilauea are briefly described. Kilauea Volcano originated on the southern slope of Mauna Loa where faults intersected the Eastern Fundamental Fissure of the Hawaiian Archipelago. The southern flank of Kilauea is cut by normal faults, along which the southern part is sliding seaward. The volcanoes of the island of Hawaii are believed to have started their activity in the Tertiary period. The great erosional period which followed deposition of the Pololu and Ninole volcanic series is placed near the end of the Pliocene. The Hilina and Hamakua volcanic series were probably erupted in the late Pliocene and earlier Pleistocene. The Hawi volcanic series and the Waawaa volcanics are probably early or middle Pleistocene in age. The main period of deposition of the Pahala ash was probably late in the middle Pleistocene or early in the upper Pleistocene. The Laupahoehoe volcanic series is late Pleistocene and Recent in age, most of the flows antedating the Wisconsin glaciation. The Hualalai volcanic series probably extends from Tertiary to historic time, and the Kau and Puna volcanic series from late Pleistocene to the present. A chapter is devoted to the petrography of the rocks in which are listed all reliable chemical rock analyses. The rocks of the island are highly permeable. Most of the rainfall sinks quickly into the ground. Perennial streams are present only on the windward slopes of Kohala Mountain and Mauna Kea. Most of the water sinks rapidly to the basal water table, where it floats on salt water according to the Ghyben-Herzberg principle. Basal water escapes in springs at or near sea level all along the coast. Only a very small proportion of it is recovered in wells. Along the windward coasts the basal water is of good quality and large supplies await development. Along the leeward coasts most of the basal water is brackish. In Kohala Mountain, much water is perched on ash beds in the Pololu volcanic series and on ash and soil at the base of the Hawi volcanic series. It escapes in perched springs in the big valleys and along the windward sea cliff and is recovered in tunnels. Along the windward slope of Mauna Keu, small amounts of water are perched by ash beds and dense lava flows in the Hamakua volcanic series. Small perched springs issue from these structures and water is recovered by tunnels. In the Kau District ash beds perch considerable water, which is recovered by many tunnels. On the southern slope of Mauna Kea small springs are perched by beds of hill wash. Dikes in the rift zones are relatively impermeable, but enclose masses of permeable rock. Water is confined at high level in the interdike compartments in Kohala Mountain, and probably in the other volcanoes. It escapes in high-level springs in the deep valleys on Kohala Mountain; some of it is recovered by tunnels. It is estimated that an average of about 13,085 million gallons of water a day falls as rain over the whole island. Of this only about 2.5 percent is visibly discharged from wells, tunnels, and springs. Large supplies of basal groundwater await development. Projects for development of additional water for the city of Hilo and the Kona District are described. Chemical analyses of water, water supplies of towns and villages, descriptions of wells, springs, and tunnels, and discharge records of numerous springs and tunnels are given in tabulated form.

Hawaii