The ground-water resources of Delaware County, New York
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New York↗
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Ground-water levels in New Mexico, 1956
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New Mexico↗
Selected hydrologic data, Tooele Valley, Tooele County, Utah
This report is intended to serve two purposes: (1) to make available to the public basic ground-water data useful in planning and studying development of water resources, and (2) to supplement an interpretive report that will be published later. Records were collected during the period 1958-63 by the U.S. Geological Survey in cooperation with the Utah State Engineer as part of the investigation of ground-water conditions in Tooele Valley, Tooele County, Utah. Additional data, collected prior to this study, can be found in the reports listed in the bibliography, and in the Water-Supply Papers of the Geological Survey listed at the beginning of table 2. The interpretive material will be published in a companion report by Joseph S. Gates. This report is most useful in predicting conditions likely to be found in areas that are being considered as well sites. The person considering the new well can spot the proposed site on plate 1 and examine the records of nearby wells as shown in the tables and figures. From table I he can note such things as depth, diameter, water level, yield, drawdown, use of water, temperature of water, and depth of perforations. By comparing the depth of perforations with the drillers' logs in table 3 he can note the type of material that yields water to the wells. Table 2 and figures 2, 3, and 4 show the historic fluctuations and trends of water levels in the vicinity. From table 4 he can note the chemical quality of the water from wells in the vicinity. Table 5 shows the amount of water discharged during 1962 from the pumped wells. If the reader decides from his examination that conditions are favorable he can place an application to drill a well with the State Engineer. If the State Engineer believes unappropriated water is available, the application may be approved after minimum statutory requirements have been satisfied. The report is also useful when planning large-scale developments of water supply. This and other uses of the report will be helped by use of the interpretive report upon its release.
Utah↗
Ground-water, surface-water, and water-chemistry data, Black Mesa area, northeastern Arizona— 2006-07
The N aquifer is the major source of water in the 5,400 square-mile Black Mesa area in northeastern Arizona. Availability of water is an important issue in northeastern Arizona because of continued water requirements for industrial and municipal use and the needs of a growing population. Precipitation in the Black Mesa area is typically about 6 to 14 inches per year. The water-monitoring program in the Black Mesa area began in 1971 and is designed to provide information about the long-term effects of ground-water withdrawals from the N aquifer for industrial and municipal uses. This report presents results of data collected for the monitoring program in the Black Mesa area from January 2006 to September 2007. The monitoring program includes measurements of (1) ground-water withdrawals, (2) ground-water levels, (3) spring discharge, (4) surface-water discharge, and (5) ground-water chemistry. Periodic testing of ground-water withdrawal meters is completed every 4 to 5 years. The Navajo Tribal Utility Authority (NTUA) yearly totals for the ground-water metered withdrawal data were unavailable in 2006 due to an up-grade within the NTUA computer network. Because NTUA data is often combined with Bureau of Indian Affairs data for the total withdrawals in a well system, withdrawals will not be published in this year's annual report. From 2006 to 2007, annually measured water levels in the Black Mesa area declined in 3 of 11 wells measured in the unconfined areas of the N aquifer, and the median change was 0.0 feet. Measurements indicated that water levels declined in 8 of 17 wells measured in the confined area of the aquifer. The median change for the confined area of the aquifer was 0.2 feet. From the prestress period (prior to 1965) to 2007, the median water-level change for 30 wells was -11.1 feet. Median water-level changes were 2.9 feet for 11 wells measured in the unconfined areas and -40.2 feet for 19 wells measured in the confined area. Spring flow was measured once in 2006 and once in 2007 at Moenkopi School Spring. Flow decreased by 18.9 percent at Moenkopi School Spring. During the period of record, flow fluctuated, and a decreasing trend was apparent. Continuous records of surface-water discharge in the Black Mesa area have been collected from streamflow gages at the following sites: Moenkopi Wash at Moenkopi (1976 to 2006), Dinnebito Wash near Sand Springs (1993 to 2006), Polacca Wash near Second Mesa (1994 to 2006), and Pasture Canyon Springs (August 2004 to December 2006). Median flows during November, December, January, and February of each water year were used as an index of the amount of ground-water discharge to the above named sites. For the period of record at each streamflow-gaging station, the median winter flows have generally remained even, showing neither a significant increase nor decrease in flows. There is not a long enough period of record for Pasture Canyon Spring for a trend to be apparent. In 2007, water samples were collected from 1 well and 1 spring in the Black Mesa area and were analyzed for selected chemical constituents. Concentrations of dissolved solids, chloride, and sulfate have varied at Peabody well 5 for the period of record, and there is an apparent increasing trend. Dissolved-solids, chloride, and sulfate concentrations increased at Moenkopi School Spring during the more than 12 years of record.
Arizona↗
A progress report on the test-well drilling program in the west part of Antelope Valley, California
This progress report presents the results of a test-well drilling program undertaken by the Antelope Valley-East Kern Water Agency and the U.S. Geological Survey in the western part of Antelope Valley, Calif. Eight test wells were drilled by the rotary method, and electric and lithologic logs were made of each well. A water-level-contour map was drawn, based on water-level measurements in the test wells and other wells. On the basis of data from these wells, the Neenach and Randsburg-Mojave faults were located. The concealed trace of another fault, north of the Randsburg-Mojave fault, was postulated from water-level data. This progress report considers the feasibility of utilizing a part of the Antelope Valley ground-water basin as a natural water-storage reservoir. The West Antelope ground-water subunit could probably be used as a large-volume holdover storage reservoir.
California↗
Water resources data for Maine, water year 1974
Water resources data for the 1974 water year for Maine including records of streamflow or reservoir storage at gaging stations, partial-record stations, and miscellaneous sites, records of water-quality data on the chemical and physical characteristics of surface- and ground-water, and records of ground-water levels in index wells are given in this report. In Part 1, records are included for 63 gaging stations, of which 62 are streamflow discharge stations, and 1 is a lake station; also are included records for 22 crest-stage partial-record stations, and 14 miscellaneous sites. In Part 2, water quality data on chemical, physical, and biological characteristics of surface and ground water were collected from designated sampling sites at predetermined intervals such as once daily, weekly, monthly, or less frequently, and at some sites data were recorded on punched paper tape at 60minute intervals. Records are given for 38 sampling stations of which 11 are continuous record stations, and 27 are miscellaneous sites. Records of chemical analyses are also given for 21 ground-water sites. In Part 3, water level data are shown for 11 ground-water wells. Locations of surface-water stations, water-quality stations, and ground-water wells are shown in figure 2. A few pertinent stations in bordering States and Provinces are also included in this report. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey under the direction of G. S. Hayes, District Chief, succeeded by C. R. Wagner. These data represent that portion of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in Maine.
Maine↗
Data on dissolved pesticides and volatile organic compounds in surface and ground waters in the San Joaquin-Tulare basins, California, water years 1992-1995
This report contains pesticide, volatile organic compound, major ion, nutrient, tritium, stable isotope, organic carbon, and trace-metal data collected from 149 ground-water wells, and pesticide data collected from 39 surface-water stream sites in the San Joaquin Valley of California. Included with the ground-water data are field measurements of pH, specific conductance, alkalinity, temperature, and dissolved oxygen. This report describes data collection procedures, analytical methods, quality assurance, and quality controls used by the National Water-Quality Assessment Program to ensure data reliability. Data contained in this report were collected during a four year period by the San Joaquin?Tulare Basins Study Unit of the United States Geological Survey's National Water-Quality Assessment Program. Surface-water-quality data collection began in April 1992, with sampling done three times a week at three sites as part of a pilot study conducted to provide background information for the surface-water-study design. Monthly samples were collected at 10 sites for major ions and nutrients from January 1993 to March 1995. Additional samples were collected at four of these sites, from January to December 1993, to study spatial and temporal variability in dissolved pesticide concentrations. Samples for several synoptic studies were collected from 1993 to 1995. Ground-water-quality data collection was restricted to the eastern alluvial fans subarea of the San Joaquin Valley. Data collection began in 1993 with the sampling of 21 wells in vineyard land-use settings. In 1994, 29 wells were sampled in almond land-use settings and 9 in vineyard land-use settings; an additional 11 wells were sampled along a flow path in the eastern Fresno County vineyard land-use area. Among the 79 wells sampled in 1995, 30 wells were in the corn, alfalfa, and vegetable land-use setting, and 1 well was in the vineyard land-use setting; an additional 20 were flow-path wells. Also sampled in 1995 were 28 wells used for a regional assessment of ground-water quality in the eastern San Joaquin Valley.
Data Series↗
Occurrence and distribution of volatile organic compounds and pesticides in ground water in relation to hydrogeologic characteristics and land use in the Santa Ana basin, southern California
This report presents an evaluation of the occurrence and distribution of VOCs and pesticides in the Santa Ana ground-water basins in relation to two types of explanatory factors: hydrogeologic characteristics and land use. The Santa Ana Basin is subdivided into the San Jacinto, the Inland, and the Coastal ground-water basins. Most wells sampled were deep and used for public supply. Data from regional studies were used to evaluate the occurrence and distribution of pesticides and volatile organic compounds (VOCs) in relation to hydrogeologic characteristics and land uses that could potentially explain variations between basins. Additional data from special studies (flow path and aquifer susceptibility) were used to evaluate potential factors affecting water quality for individual basins. The hydrogeologic characteristics evaluated in this report were hydrogeologic setting, ground-water age, depth to the top of the well screen (top of well perforations), and proximity to engineered recharge facilities. Urban land use, agricultural land use, and population density were characterized within a 500-meter radius of sampled wells and at the basin scale. Aquifers in the San Jacinto Basin are generally unconfined, and major land-use categories are urban (33 percent), agricultural (37 percent), and undeveloped (25 percent). Recharge is primarily from the overlying landscape, but engineered recharge is locally important in the Hemet area. VOCs and pesticides were detected more frequently in younger ground water (less than 50 years old) than in older ground water, and more frequently in shallower wells than deeper wells; the numbers of VOCs and pesticides detected also were significantly higher in the younger ground water and in the shallower wells. In the Hemet area of the San Jacinto Basin, VOCs and pesticides were detected more frequently in wells proximal to engineered recharge facilities than in distal wells. These patterns illustrate the importance of proximity to sources of recharge in relation to the occurrence and distribution of VOCs and pesticides in ground water. Aquifers in the Inland Basin also are generally unconfined, and the major land-use category is urban (58 percent), with lesser amounts of agricultural (13 percent) and undeveloped (28 percent) land. Recharge is from engineered facilities that utilize local runoff and imported water and from vertical infiltration. VOCs and pesticides were detected more frequently in younger ground water than in older ground water, and more frequently in shallower wells than deeper wells. The number of VOCs detected per well also was significantly higher in the younger ground water and in the shallower wells. Several solvent plumes extending between 5 and 10 kilometers illustrate the large distances that contaminants travel in basins with intensive use of ground water. Aquifers in the Coastal Basin, in contrast to the other basins, are generally confined. Land use in the basin is largely urban (80 percent), with lesser amounts of agricultural (7 percent) and undeveloped (12 percent) land. Recharge is primarily from engineered facilities that utilize water diverted from the Santa Ana River and imported water. Consequently, VOCs and pesticides were detected more frequently in wells proximal to engineered recharge facilities than in distal wells. These compounds were also detected more frequently in the unconfined area than in the confined area of the basin. In the confined area, the numbers of VOCs and pesticides detected per well were not significantly different in wells with shallower and deeper screens. This distribution reflects the dominance of lateral flow and insulation from overlying land use in the confined aquifers of the Coastal Basin. In the unconfined area of the Coastal Basin, the numbers of VOCs and pesticides detected per well were significantly higher in shallower wells than in deeper wells. VOC and pesticide detections were not statist
Scientific Investigations Report↗
Drought-trigger ground-water levels in Chester County, Pennsylvania, for the period of record ending May 2006
This report presents the results of a study by the U.S. Geological Survey (USGS), in cooperation with the Chester County Water Resources Authority (CCWRA), to update the drought-trigger water levels for the Chester County observation-well network. The Chester County observation-well network was established in 1973 through a cooperative agreement between the CCWRA and the USGS to monitor local ground-water levels and trends and to determine drought conditions. In 1990 and again in 1997, drought-warning and drought-emergency water-level triggers were determined for the majority of wells in the existing Chester County observation-well network of 23 wells. Since 1997, the Chester County observation-well network expanded to 29 wells, some of the original wells were destroyed, and additional monthly water-level observations were made to allow for better statistical relations. Because of these changes, new statistics for water-level triggers were required. For this study, 19 of the 29 wells in the observation-well network were used to compute drought-trigger water levels. An additional 'drought-watch water-level trigger' category was developed to make the Chester County drought-trigger water-level categories consistent with those implemented by the Pennsylvania Department of Environmental Protection (PaDEP). The three drought-trigger water-level categories, as defined by PaDEP are 1) 'drought watch' when at the 75th-percentile level; 2) 'drought warning' when at the 90th-percentile level; and 3) 'drought emergency' when at the 95th-percentile level. A revised methodology, resulting from longer periods of record representing ground-water and climatic conditions and changes in local water use, has resulted in some observed differences in drought-trigger water levels. A comparison of current drought-trigger water levels to those calculated in 1997 shows the largest mean annual change in percentile values was in northeastern Chester County. In this northeastern region, the average 90th-percentile water levels changed by as much as 1.84 feet (17.5 percent) from those determined in 1997. Other observation wells in the county generally exhibited a smaller mean annual change in percentile values; a typical change was less than 0.5 foot. While most revisions in the drought-trigger water levels generally can be attributed to different methodology and (or) the additional years of data collected under existing climatic conditions, anthropogenic influences, such as the cessation of local pumping stresses, also were shown to cause changes in the drought-trigger water levels determined in this study.
Pennsylvania↗
Simulated effects of 1994 salt-mine collapse on ground-water flow and land subsidence in a glacial aquifer system, Livingston County, New York
This report describes the hydrogeology of the Genesee Valley and the effects of the ceiling collapse of the Retsof salt mine on the aquifer system. It discusses the origin and character of glacial sediments; the occurrence, flow directions, and chemical quality of water in the aquifer system before the collapse; the effects of the collapse on the aquifer system in terms of land subsidence, water-level declines, changes in water quality, and exsolution of natural gas, and design and calibration of the ground-water-flow model. It also presents results of flow-model simulations, including an estimated ground-water budget and graphs showing the simulated water-level recovery; and results of subsidence simulations, including maps and graphs showing the extent of land subsidence.
New York↗
Ground-water resources of north-central Connecticut
The term 'north-central Connecticut' in this report refers to an area of about 640 square miles within the central lowland of the Connecticut River basin north of Middletown. The area is mostly a broad valley floor underlain by unconsolidated deposits of Pleistocene and Recent age which mantle an erosional surface formed on consolidated rocks of pre-Triassic and Triassic age. The mean annual precipitation at Hartford, near the center of the area, is 42.83 inches and is uniformly distributed throughout the year. The average annual streamflow from the area is about 22 inches or about half the precipitation. The consolidated water-bearing formations are crystalline rocks of pre-Triassic age and sedimentary and igneous rocks of the Newark group of Triassic age. The crystalline rocks include the Middletown gneiss, the Maromas granite gneiss, the Glastonbury granite-gneiss of Rice and Gregory (1906), and the Bolton schist which form the basement complex and the Eastern Upland of north-central Connecticut. Enough water for domestic, stock, and small commercial use generally can be obtained from the crystalline rocks. Recoverable ground water occurs in the interconnected joints and fracture zones and is yielded in amounts ranging from 29 to 35 gpm (gallons per minute) to wells ranging in depth from 29 to 550 feet. The sedimentary rocks of Triassic age underlie all the Connecticut River Lowland and are predominantly arkosic sandstone and shale. Water supplies sufficient for domestic, stock, and small commercial use can be obtained from shallow wells penetrating these rocks, and larger supplies sufficient for industries and smaller municipalities can probably be obtained from deeper wells. Reported yields range from ? to 578 gpm; the larger yields are generally obtained from wells between 300 and 600 feet in depth. Yields are larger where the overlying material is sand and gravel or where the rocks are well fractured. The igneous rocks of Triassic age are basalt and have water-bearing characteristics similar to the crystalline rocks. The unconsolidated deposits comprise ground-moraine and drumlin deposits, ice-contact deposits, outwash-plain and valley-train deposits, and glaciolacustrine and associated delta deposits of Pleistocene age, as well as dune deposits, good-plain deposits, and swamp deposits of Recent age. Ground-moraine deposits occur throughout the area but yield only small quantities of water. The ice-contact deposits consisting mostly of sand and gravel form kames, kame terraces, and crevasse fillings and are the surface deposits in three extensive areas along the eastern margin of the Connecticut River Lowland. The deposits in most places are saturated and, where they consist of well-sorted material, are highly permeable, yielding as much as 750 gpm to properly constructed wells. Outwash-plain and valley-train deposits and bodies of undifferentiated outwash underlie the surface in the eastern and southern parts of the area. These deposits consist of well-sorted sand and silt and some pebble gravel ranging in thickness from nearly zero to more than 225 feet in places. The thicker deposits are an important source of moderate supplies of ground water. Screened wells of moderate depth commonly yield about 150 gpm, but some yield as much as 400 gpm. Bodies of buried outwash deposits of irregular size and shape occur in the bottoms of some of the filled bedrock valleys. They seldom are more than 20-30 feet thick. Their permeability Is generally low because of the high percentage of silt; yields as much as 30 gpm to domestic wells are reported. Under most favorable conditions, these deposits yield as much as 500 gpm. The glaciolacustrine and associated delta deposits occur in nearly all parts of north-central Connecticut and are potential sources of moderate supplies of ground water. They consist of well-sorted sand which generally grades downward into varved clay and silt. The deposits of sand are thic
Water Supply Paper↗
Hydrogeology and Ground-Water Quality of Brunswick County, North Carolina
Brunswick County is the southernmost coastal county in North Carolina and lies in the southeastern part of the Coastal Plain physiographic province. In this report, geologic, hydrologic, and chemical data were used to investigate and delineate the hydrogeologic framework and ground-water quality of Brunswick County. The major aquifers and their associated confining units delineated in the Brunswick County study area include, from youngest to oldest, the surficial, Castle Hayne, Peedee, Black Creek, upper Cape Fear, and lower Cape Fear aquifers. All of these aquifers, with the exception of the Castle Hayne aquifer, are located throughout Brunswick County. The Castle Hayne aquifer extends across only the southeastern part of the county. Based on available data, the Castle Hayne and Peedee confining units are missing in some areas of Brunswick County, which allows direct hydraulic contact between the surficial aquifer and underlying Castle Hayne or Peedee aquifers. The confining units for the Black Creek, upper Cape Fear, and lower Cape Fear aquifers appear to be continuous throughout Brunswick County. In examining the conceptual hydrologic system for Brunswick County, a generalized water budget was developed to better understand the natural processes, including precipitation, evapotranspiration, and stream runoff, that influence ground-water recharge to the shallow aquifer system in the county. In the generalized water budget, an estimated 11 inches per year of the average annual precipitation of 55 inches per year in Brunswick County is estimated to infiltrate and recharge the shallow aquifer system. Of the 11 inches per year that recharges the shallow system, about 1 inch per year is estimated to recharge the deeper aquifer system. The surficial aquifer in Brunswick County is an important source of water for domestic supply and irrigation. The Castle Hayne aquifer is the most productive aquifer and serves as the principal ground-water source of municipal supply for the county. The upper part of the Peedee aquifer is an important source of ground-water supply for domestic and commercial use. Ground water in the lower part of the Peedee aquifer and the underlying aquifers is brackish and is not known to be used as a source of supply in Brunswick County. Most of the precipitation that recharges the surficial aquifer is discharged to local streams that drain into the Waccamaw River, Cape Fear River, and Atlantic Ocean. Recharge to the Castle Hayne aquifer occurs primarily from the surficial aquifer. Recharge to the Peedee aquifer occurs primarily from the surficial and Castle Hayne aquifers, with some upward leakage of water also occurring from the underlying Black Creek aquifer. Discharge from the Castle Hayne and Peedee aquifers occurs to local streams, the Cape Fear River, and the Atlantic Ocean. Evaluation of water-level data for the period January 1970 through May 2002 indicated no apparent long-term temporal trends in water levels in the surficial and Castle Hayne aquifers and in the upper part of the Peedee aquifer. The most significant water-level trends were noted for wells tapping the lower part of the Peedee aquifer and tapping the Black Creek aquifer where water levels have declined as much as 41 and 37 feet, respectively. These ground-water-level declines are attributed to regional ground-water pumping in areas outside of Brunswick County. Water-level data for Brunswick County wells tapping the upper Cape Fear and lower Cape Fear aquifers tend to fluctuate within a fairly uniform range with no apparent temporal trend noted. Analysis of vertical hydraulic gradients during this same period primarily indicate downward flow of ground water within and among the surficial, Castle Hayne, and Peedee aquifers. The vertical flow of ground water in the Black Creek aquifer is upward into the overlying Peedee aquifer. Upward flow also is noted for the upper and lower Cape Fear aquifers. Historic and recent analytic data were evaluated to better understand the sources of water contained in Brunswick County aquifers and the suitability of the water for consumption. Based on analytical results obtained for recent samples collected during this study, ground water from the surficial aquifer, Castle Hayne aquifer, and upper part of the Peedee aquifer appears to be generally suitable for drinking water. Although concentrations of iron and manganese commonly exceeded the drinking-water standards, the concern generally associated with the occurrence of these analytes in a water supply is one of aesthetics. In all samples, nitrate, nitrite, and sulfate were detected at concentrations less than drinkingwater standards. Based on historic analytical data, the brackish water in the lower part of the Peedee aquifer and in the Black Creek, upper Cape Fear, and lower Cape Fear aquifers is classified as a sodium-chloride type water. The presence of brackish water in these deeper systems combined with upward vertical gradients presents the potential for upward migration of brackish water into overlying aquifers, or upconing beneath areas of pumping. The current (2001) location of the boundary between freshwater and brackish water in Brunswick County aquifers is unknown.
North Carolina↗
Surficial geologic map of northern Adak Island, Alaska
Surficial deposits on northern Adak Island, Alaska include a variety of volcanic, glacial, eolian, and beach sediments. These deposits are the primary water-bearing units on the island and their distri- bution is shown on the accompanying surficial geologic map. An extensive sequence of volcanic debris-flow deposits (lahars) was identified on the eastern slope of Mount Moffett. The sedimentary characteristics of the lahar deposits indicate that they are related to volcanic eruptions of Mount Moffett and are evidence for Holocene volcanic activity at this volcano. Similar lahar deposits also are present on the southern slopes of Mount Adagdak. The surficial geologic map units described in the report are a basis for island-wide assess- ments of ground-water conditions, aquifer proper- ties, and general hydrogeologic conditions, and will be useful for determining the availability of potential construction materials.
Alaska↗
Description, Properties, and Degradation of Selected Volatile Organic Compounds Detected in Ground Water--A Review of Selected Literature
This report provides abridged information describing the most salient properties and biodegradation of 27 chlorinated volatile organic compounds detected during ground-water studies in the United States. This information is condensed from an extensive list of reports, papers, and literature published by the U.S. Government, various State governments, and peer-reviewed journals. The list includes literature reviews, compilations, and summaries describing volatile organic compounds in ground water. This report cross-references common names and synonyms associated with volatile organic compounds with the naming conventions supported by the International Union of Pure and Applied Chemistry. In addition, the report describes basic physical characteristics of those compounds such as Henry's Law constant, water solubility, density, octanol-water partition (log Kow), and organic carbon partition (log Koc) coefficients. Descriptions and illustrations are provided for natural and laboratory biodegradation rates, chemical by-products, and degradation pathways.
Open-File Report↗
Ground-water, surface-water, and water-chemistry data, Black Mesa area, northeastern Arizona— 2005-06
The N aquifer is the major source of water in the 5,400 square-mile Black Mesa area in northeastern Arizona. Availability of water is an important issue in northeastern Arizona because of continued water requirements for industrial and municipal use and the needs of a growing population. Precipitation in the Black Mesa area averages about 6 to 14 inches per year. The water monitoring program in the Black Mesa area began in 1971 and is designed to provide information about the long-term effects of ground-water withdrawals from the N aquifer for industrial and municipal uses. This report presents results of data collected for the monitoring program in the Black Mesa area from January 2005 to September 2006. The monitoring program includes measurements of (1) ground-water pumping, (2) ground-water levels, (3) spring discharge, (4) surface-water discharge, (5) ground-water chemistry, and (6) periodic testing of ground-water withdrawal meters. In 2005, ground-water withdrawals in the Black Mesa area totaled 7,330 acre-feet, including ground-water withdrawals for industrial (4,480 acre-feet) and municipal (2,850 acre-feet) uses. From 2004 to 2005, total withdrawals increased by less than 2 percent, industrial withdrawals increased by approximately 3 percent, and total municipal withdrawals increased by 0.35 percent. From 2005 to 2006, annually measured water levels in the Black Mesa area declined in 10 of 13 wells in the unconfined areas of the N aquifer, and the median change was -0.5 foot. Measurements indicated that water levels declined in 12 of 15 wells in the confined area of the aquifer, and the median change was -1.4 feet. From the prestress period (prior to 1965) to 2006, the median water-level change for 29 wells was -8.5 feet. Median water-level changes were -0.2 foot for 13 wells in the unconfined areas and -46.6 feet for 16 wells in the confined area. Ground-water discharges were measured once in 2005 and once in 2006 at Moenkopi School Spring and Burro Spring. Discharge decreased by 3.5 percent at Moenkopi School Spring and by 15 percent at Burro Spring. During the period of record at each spring, discharges fluctuated; a decreasing trend was apparent. Continuous records of surface-water discharge in the Black Mesa area have been collected from streamflow gages at the following sites: Moenkopi Wash (1976 to 2005), Dinnebito Wash (1993 to 2005), Polacca Wash (1994 to 2005), Pasture Canyon Spring (August 2004 to December 2005), and Laguna Creek (1996 to 2005). Median flows during November, December, January, and February of each water year were used as an index of the amount of ground-water discharge to the above named sites. For the period of record at each streamflow-gaging station, the median winter flows have decreased for Moenkopi Wash, Dinnebito Wash, and Polacca Wash. There is not a long enough period of record for Pasture Canyon Spring and Laguna Creek was discontinued at the end of December 2005. In 2006, water samples were collected from 6 wells and 2 springs in the Black Mesa area and analyzed for selected chemical constituents. Dissolved-solids concentrations ranged from 111 to 588 milligrams per liter. Water samples from 5 of the wells and both of the springs had less than 500 milligrams per liter of dissolved solids. Trends in the chemistry of water samples from the 6 wells show the Pi?on NTUA 1 and Peabody 9 wells increasing in dissolved solids, Forest Lake NTUA 1 and Peabody 2 wells decreasing in dissolved solids, and Kykotsmovi PM2 and Keams Canyon PM2 wells show a steady trend. Increasing trends in dissolved-solids, chloride, and sulfate concentrations were evident from the more than 11 years of data for the 2 springs.
Arizona↗
Simulation of ground-water flow in the Mesilla basin, Dona Ana County, New Mexico, and El Paso County, Texas; supplement to Open-File Report 88-305
No abstract available.
New Mexico, Texas↗
Documentation of a Conduit Flow Process (CFP) for MODFLOW-2005
This report documents the Conduit Flow Process (CFP) for the modular finite-difference ground-water flow model, MODFLOW-2005. The CFP has the ability to simulate turbulent ground-water flow conditions by: (1) coupling the traditional ground-water flow equation with formulations for a discrete network of cylindrical pipes (Mode 1), (2) inserting a high-conductivity flow layer that can switch between laminar and turbulent flow (Mode 2), or (3) simultaneously coupling a discrete pipe network while inserting a high-conductivity flow layer that can switch between laminar and turbulent flow (Mode 3). Conduit flow pipes (Mode 1) may represent dissolution or biological burrowing features in carbonate aquifers, voids in fractured rock, and (or) lava tubes in basaltic aquifers and can be fully or partially saturated under laminar or turbulent flow conditions. Preferential flow layers (Mode 2) may represent: (1) a porous media where turbulent flow is suspected to occur under the observed hydraulic gradients; (2) a single secondary porosity subsurface feature, such as a well-defined laterally extensive underground cave; or (3) a horizontal preferential flow layer consisting of many interconnected voids. In this second case, the input data are effective parameters, such as a very high hydraulic conductivity, representing multiple features. Data preparation is more complex for CFP Mode 1 (CFPM1) than for CFP Mode 2 (CFPM2). Specifically for CFPM1, conduit pipe locations, lengths, diameters, tortuosity, internal roughness, critical Reynolds numbers (NRe), and exchange conductances are required. CFPM1, however, solves the pipe network equations in a matrix that is independent of the porous media equation matrix, which may mitigate numerical instability associated with solution of dual flow components within the same matrix. CFPM2 requires less hydraulic information and knowledge about the specific location and hydraulic properties of conduits, and turbulent flow is approximated by modifying horizontal conductances assembled by the Block-Centered Flow (BCF), Layer-Property Flow (LPF), or Hydrogeologic-Unit Flow Packages (HUF) of MODFLOW-2005. For both conduit flow pipes (CFPM1) and preferential flow layers (CFPM2), critical Reynolds numbers are used to determine if flow is laminar or turbulent. Due to conservation of momentum, flow in a laminar state tends to remain laminar and flow in a turbulent state tends to remain turbulent. This delayed transition between laminar and turbulent flow is introduced in the CFP, which provides an additional benefit of facilitating convergence of the computer algorithm during iterations of transient simulations. Specifically, the user can specify a higher critical Reynolds number to determine when laminar flow within a pipe converts to turbulent flow, and a lower critical Reynolds number for determining when a pipe with turbulent flow switches to laminar flow. With CFPM1, the Hagen-Poiseuille equation is used for laminar flow conditions and the Darcy-Weisbach equation is applied to turbulent flow conditions. With CFPM2, turbulent flow is approximated by reducing the laminar hydraulic conductivity by a nonlinear function of the Reynolds number, once the critical head difference is exceeded. This adjustment approximates the reductions in mean velocity under turbulent ground-water flow conditions.
Techniques and Methods↗
Geology of the western Everglades area, southern Florida
Introduction During 1950, a series of 43 test wells 30 feet deep were drilled by the United States Corps of Engineers along the western edge of the Everglades from the Tamiami Canal northward to the Caloosahatchee River. The cores obtained from the wells afford geologic data along a line from the lower Everglades of Dade County, where both the geology and water resources have been investigated, to the Caloosahatchee River area, where the surface geology has been studied. This report has been prepared chiefly to record and interpret the information obtained from the test wells. It is one of a series prepared on ground-water investigations by the United States Geological Survey, in cooperation with the Florida Geological Survey. When ground-water data become available they will be correlated with the geology of this report and will be presented in a later report on the Glades-Hendry Counties area. A few generalized inferences concerning ground water are made. The investigation was under the general supervision of A. N. Sayre, Chief, Ground Water Branch, U. S. Geological Survey, Washington, D. C., and Herman Gunter, Director, Florida Geological Survey, and under the direct supervision of Nevin D. Hoy, District Geologist, U. S. Geological Survey, Miami, Fla.
Florida↗