ALBERT

Notes: Most ground-water aquifers have a multibarrier natural defense system. With all these natural defenses, why are there so many contaminated wells? In most cases the well itself is the path of entrance for the contamination. The American Water Works Association and the National Water Well Association state in their joint Standard for Deep Wells: “Only when the sole available water-bearing formation lies so near the surface that it is continually contaminated is production of a safe supply not feasible.” Only in very rare circumstances is it economically justified to substitute disinfection for adequate protection of a ground-water source.Rapid changes in well water quality with pumping time indicate less than optimum construction. Poorly constructed and abandoned wells serve as unauthorized and uncontrolled ground-water recharge points and have a degrading effect on ground-water quality. Water quality improvement should begin with excluding water of undesirable quality from the source of supply. For the home owner and farmer to profit from this ideal it must be accepted by well drillers, water conditioning dealers, and county and State health departments.

Notes: The problem of predicting water level changes in an aquifer due to variable pumpage is approached by using the convolution integral. Equations for a nonleaky artesian aquifer and a leaky artesian aquifer with negligible storage in the confining layer are presented. Computational results compare favorably with type curves for hypothetical cases with constant pumping. A practical example using variable pumpage from several pumping centers shows the applicability of the technique and its value in interpreting water level variations.

Notes: Future water demands were estimated for each 10-year interval from 1980 to 2020 for areas in the Chicago region dependent upon ground water as a source of supply. Demands were compared with ground-water availability to define water deficient areas. Two approaches were considered in developing the ground-water resource. The first approach limits ground-water withdrawals to the maximum rate of natural ground-water recharge that can be induced by pumping. The second approach allows withdrawals to exceed natural recharge. When limiting ground-water withdrawals to recharge a large part of the region will require importation of water by as early as 1980. With proper pumpage distribution it is conceivable that there is sufficient water that can be withdrawn (mined) in excess of natural recharge to meet demands through the year 2020.

Notes: A set of type-curves is presented which simplifies and quickens the solution of the Rorabaugh equation for drawdown in a pumping well by eliminating the trial-and-error computations. Type-curve analysis of test data in the field, before pumping is discontinued, provides an indication of the accuracy and adequacy of test data points. For optimum accuracy, test data should cover the portion of maximum curvature of the curve, and the range between the lowest and the highest pumping rates used in the step-drawdown test should be great enough to define a unique curve.

Notes: Four subsurface disposal wells have been drilled and completed in Alabama. These are: Stauffer Chemical Company, Mobile County; Ciba-Geigy, Inc., Washington County; U. S. Steel Corp., Jefferson County; and Reichhold Chemicals, Inc., Tuscaloosa County. The Geological Survey of Alabama has been directly involved in all four projects. The Survey served as a consultant to the Alabama Water Improvement Commission, the State agency responsible for protection of surface and ground water in Alabama, on the Stauffer and Ciba-Geigy projects, and as consultant and supervisor on the U. S. Steel Corporation and Reichhold Chemicals, Inc., projects. These projects were undertaken as a research effort to insure that the responsible State agencies are fully cognizant of all aspects of this method of waste disposal. It is a policy in Alabama that subsurface disposal is permissible for some wastes if the well is properly designed and completed in an appropriate geologic environment and if conventional methods of waste treatment have been evaluated and proved to be inadequate.The Stauffer well, operating at 75 gallons per minute and 500 psi, is the only subsurface disposal system, other than oilfield brine disposal wells, that is currently in operation. The Stauffer and Ciba-Geigy wells are in the Coastal Plains geological province and the U. S. Steel and Reichhold Chemicals, Inc., wells are in Paleozoic sediments of the Warrior Basin. A general discussion of the geology, drilling, completion, and testing techniques is presented for the two geologic provinces involved.

Notes: A comprehensive examination was made of a shallow farm well which was contaminated with persistent pesticides when contaminated soil was used as backfill material around the well casing. The well location was less than 25 feet from a site previously used for flushing an insecticide sprayer.Pesticide level in the water has been monitored for more than 4 years, during which a gradual decline in concentration has occurred. Soil core samples taken in the area surrounding the well indicate relatively high surface contamination but very little downward movement. Sediment samples from the bottom of the well exhibited highest concentration of all samples.

Notes: The resistance-capacitance electrical analogue is used to analyse the time variant behaviour of aquifers which change between the confined and unconfined states. This is achieved using a field effect transistor as a switch which automatically operates as the water table crosses the top of the aquifer.The significance of this change for a particular limestone aquifer is described. In addition a thorough examination is made of the changes to the pumping test time-drawdown curves when an aquifer, which is initially confined, becomes unconfined. If standard methods are used for this problem, erroneous results will be obtained for the transmissibility and the storage coefficients.

Notes: In the fall and winter of 1967–68, a 2,587-foot test well was drilled at Moore's Bridges Filter Plant, Norfolk, Virginia. The well penetrated rocks of post-Miocene, late and middle Miocene, late Eocene, Cenomanian, Cenomanian and Albian, Albian and Aptian, and Aptian and Neocomian age.Empirical data must be established in the Tidewater area for the successful calculation of ground-water quality from calibrated geophysical logs. Chemical analyses of water samples from seven separate zones at depths between 850 feet to 2,500 feet below sea level indicate that the water type changes from a predominantly sodium bicarbonate water above 1,700 feet to a sodium chloride water in the deeper zones. The sodium bicarbonate type water in shallow aquifers must be corrected for divalent cation effects when using the self potential method or for the bicarbonate effect when using the resistivity method of interpretation.Using calibrated geophysical logs, an approximation of the dissolved-solids and chloride content may be calculated using the formula Rw= Ro/Ff and the appropriate figures in the text. A field formation factor (Ff) of 4.2 is proposed for the Cretaceous aquifers in the Atlantic Coastal area. A K value of 84 should be used to check the validity of the magnitude of the self potential curve for the fresh- and brackish-water aquifers in the Cretaceous. If the amount of dissolved solids is known for the Cretaceous waters, the chloride content may be approximated by the formula Cl = 0.5 (dissolved solids–300), provided the dissolved solids are less than 3,500 mg/l (milligrams per liter), and by the formula Cl = 0.6 (dissolved solids–400), if the dissolved solids are greater than 3,500 mg/l. In the Tidewater area, if the saturated resistivity (Ro) reading on the electric log is less than 25 ohmmeters the total solids and chloride content of the water are probably in excess of Public Health standards for potable water. An empirical method of calculating the quality of water from electric logs is presented.

Notes: Measurement of the depth to water in wells can be accomplished by timing the fall of a marble or BB. Depth to water can also be determined in terms of the frequency of the reverberations heard in a well. These two methods are called the rock and the bong techniques respectively. Their theoretical basis, their proper execution, and their usefulness are discussed.

Notes: The feasibility of determining the ground-water contribution to stream flow during periods of storm runoff by continuous monitoring of a stream's electrical conductance was investigated. Methods involving graphical techniques or ground-water stage versus base flow rating curves are generally used to determine the ground-water contribution, but the ground-water contribution can also be estimated if stream flow and the conductance of surface water and of ground water are known. The conductance method was tested on a 95-square-mile basin in north-central Illinois. Continuous records of stream flow, stream-flow conductance, and ground-water stage within the basin were collected. A rating curve of base flow versus mean ground-water stage was constructed, and ground-water discharges determined from the rating curve were compared with those computed from conductance data. The conductance method normally gave a lower estimate of the ground-water contribution than did the rating-curve method. However, analyses of storms which were preceded by extended dry periods resulted in much lower estimates of ground-water discharge by the rating-curve method than by the conductance method. The conductance method offers a simple alternative for use in areas where observation wells are unavailable or where rating curves are difficult to construct.

Notes: Observation wells and access holes for neutron probe use were drilled by a jet-percussion drill rig in coarse alluvial material near Tucson, Arizona. The method combines the jetting action which effectively removes loose materials with the percussion necessary to break up tighter formations and large particles. A unique feature of the equipment is the provision for simultaneous drilling and driving the casing to keep the hole open in loose formations. Washed samples of the material being drilled can be obtained from the recirculating water system. Drilling rates were from seven to ten feet per hour, and costs including casing were less than $1.50 per foot. Maximum depth is about 100 feet.Hydrologic study of a ground-water reservoir requires access to the aquifer. Observations are made where the water table intersects the land surface, such as at springs or seeps, or through existing wells. However, wells are not always found in desired locations or are pumped so heavily that their usefulness as observation wells is impaired. Measurements are also made in the unsaturated zone with neutron moisture measuring equipment, which requires a small diameter cased access hole for the neutron probe.An observation well needs a diameter only large enough for access by measuring devices and must be immediately responsive to changes in aquifer water level. For neutron probe use, the required diameter is about two inches, and the well must have no significant effect on moisture movement in the unsaturated zone. To meet these requirements the drilling process should have no lasting effect on the formation surrounding the well. Finally, since the wells have no economic utility, construction cost must be low.A network of observation wells and neutron probe access holes was drilled as part of a project to evaluate the natural recharge from Rillito Creek near Tucson, Arizona. The formation along the creek bed is a coarse alluvial outwash containing almost no clay, considerable running sand, and some large gravel and boulders. Commercial churn (percussion) and hydraulic rotary drills, commonly used for drilling in this area, were first tried but encountered much difficulty in the loose materials.Previous investigators used jetting equipment drill small diameter holes in a variety of alluvi formations (Cederstrom and Tibbitts, 1961; Bowma: 1911; and Pillsbury and Christiansen, 1947). Howeve in most cases, either open hole drilling was used because the fine material content and the limited numb. of boulders or large gravel particles made this methc possible, or drilling mud was used to maintain th hole. The jetting method uses water pumped unde pressure through hollow rods and a drill bit to loose the material and carry it to the surface. The jettin water receives little aid from the drill in loosenin the material to be removed. Usually the drill cutting are settled out in a tank or basin, and the water i recirculated.

Notes: Artificial recharge with tertiary treated sewage effluent has been suggested as one remedial measure for projected ground-water deficits in the Chicago region. A deep sandstone aquifer, an important source of ground water in the region, offers the best opportunity for artificial recharge. Recharge will be through wells since the aquifer is deeply buried. Expected problems in maintaining well injection capacity were studied by recharging treated effluent through formation cores of the sandstone. Some success was had in maintaining recharge rates at constant heads for several days.

Notes: The application of borehole geophysics to study of basalt hydrogeology has been pursued at Washington State University for the past six years. Throughout this period much effort has been directed to redesign of commercial geophysical system components and development of expanded downhole capabilities. It has been demonstrated that composite logging techniques can be used to define the hydraulic regime of a well constructed in basalt. Certain of the logging measures, with further study, may become powerful tools for identifying anomalous conditions associated with pollutant dispersion in an aquifer. Positive correlations of basalt with the logging methods have not yet been made over distances greater than 20 miles. However, as improved logging density permits intermediate points of correlation to be established, further extensions are anticipated. Both major and minor log features of the basalts display varying degrees of lateral persistence. Because driller's logs are generally inadequate in describing subtleties of basalt geology, subsurface correlations are best made with geophysical logs. In areas with extensive surficial cover, the geophysical methods may prove to be a very practical method of determining basalt stratigraphy. Geophysical well logging offers to agencies charged with ground-water management many opportunities for gaining new knowledge which have been largely neglected.

Notes: This study provides cost information for private home ground-water supply systems in Illinois. Relatively accurate cost predictions for different types and depths of wells, ranging in cost from about $150 to $2400, can be made from the graphs presented. The average cost of all wells studied is about $575. Cost data for pumping systems equipped with 10-gpm submersible pumps (approximately 50 percent of all collected data) show that the average cost of these systems is about $585 with 50 percent ranging between $400 and $680.The costs of treating water for domestic use also are summarized. Two graphs illustrate the monthly costs of softening and removing iron at varying monthly consumption rates and concentrations of hardness-forming minerals and iron. The monthly cost of continuous chlorination is calculated.Use of the data presented makes it possible to estimate the monthly costs of raw and treated water from a domestic ground-water supply. Two maps show the probable costs of domestic raw water-supply systems from sand and gravel wells and bedrock wells throughout the State. For an average installation and domestic use rate in Illinois, the monthly cost of raw water is about $11.00, softened water $15.40, softened water treated for iron $22.00, and softened water treated for iron and chlorinated $25.00. Similar calculations for any type and depth of well, water quality, and treatment can be made from the information in this report. This material should provide adequate information for planning purposes and decision making in developing a desired domestic supply.

Notes: Procedures are developed and charts are presented to determine the unsteady drawdown in a group of wells which are located along a straight line and fully penetrate a homogeneous, isotropic, artesian aquifer. Based on the linearity of the governing field equation, the principle of superposition is used to combine the effects of individual wells, and solutions are obtained by using a digital computer to evaluate an exponential integral. The concepts of equivalent radius, coefficient of interference, and degree of uniformity are introduced, and quantitative graphical relationships are given as functions of the independent variables, which are the number of wells, well spacing, and time.

Notes: Ground water in the arid coastal area of Peru occurs in more than fifty alluvial aquifers. The aquifers are limited to river valleys and to nearby sedimentary plains.The coast is rainless and the river valleys serve as the drainage outlet of the western slopes of the Andes. The coastal alluvial aquifers are located below the lower limit of the active catchment areas, and are not recharged directly by precipitation.The long igneous batholith and the volcanic formations of the Andean Cordillera form an impermeable barrier which prevents the replenishment of the aquifers by underflow from the Andes.The main source of replenishment of the aquifers in the Peruvian coastal zone is river water. The water infiltrates through the river beds and irrigation canals and migrates laterally within the alluvial deposits. Another important source of recharge is return flow from irrigation. Water also enters the aquifers through boundary faults.

Notes: Drinking water for more than 50 million Americans is supplied from individual wells, springs, rain-water catchments or unprotected surface-water sources. The choice of water source is usually controlled by individual economic factors, and climatic, geologic and geographic considerations. This segment of the nation's population lives in the rural and suburban areas of the United States remote from existing community water supply distribution lines.The United States Public Health Service has shared, for many years, the concern of the various State Health Departments regarding the sanitary quality of individual water supplies. It has been generally concluded by public health officials, both Federal and State, that safe water supplies are not available to many homes in the United States. The rapid technological advances in industry, agriculture and transportation in recent years have intensified the potential of pollution of the environment, both chemically and biologically. The spread of pollution is accompanied by the increased hazard of water-borne disease and associated illnesses.During the summer of 1969 the Bureau of Water Hygiene*, Environmental Health Service, with the cooperation of the Georgia State Health Department, conducted a systematic survey of individual water supplies in 4 counties in the State of Georgia. The results of the survey indicate that more than ⅓ of the water supplies sampled are potentially hazardous to the users, and that there is a definite relationship of the geologic environment and type of water supply to the nature of the contamination.

Notes: Two pit recharge tests were conducted at an instrumented research site near Tucson, Arizona using cooling tower blowdown effluent from a nearby power plant. The first trial in 1966 consisted of 142 days of continuous inundation. The second test in 1968, comprised 15 wet-dry cycles with a total inundation time of 80 days. Quantities recharged by the two management techniques were contrasted. Water content profiles, obtained via a “moisture logger” in 14 access wells, clearly delineated two principal zones of water transmission on mounds within stratified materials of the 80 ft zone of aeration at the site. During the continuous inundation test three stages were apparent in the history of these mounds: growth stage, equilibrium stage and drainage stage. It was possible to relate these various stages to intake characteristics of the pit. The development of models to characterize recharge within the zone of aeration in areas of the Tucson basin with geological controls similar to those at the recharge site, should accommodate the three stages in the history of mound development and dissipation.

Notes: A reconnaissance of parts of the former West Aden Protectorate enables a characterization of the dominant hydrologic elements to be made. In this desert environment intermittent streams from the east-west range of mountains provide considerable water for flood irrigation and groundwater recharge of alluvial fans along the Gulf of Aden. High yield wells are developed in the coastal area and in at least one alluvial area on the back slope facing the Empty Quarter. Ground water in the interior is generally restricted to areas where wadi flow provides occasional recharge. Relatively few rock wells have been drilled in the area. Many wells in the alluvium yield silty water leading to clogging of the wells and undue pump wear.

Notes: The economic potential of the Mekong Delta is largely unrealized because of the harmful effects of uncontrolled flows of surface water which occur generally during the period August-October. Interest in the Delta by various government agencies has resulted in preliminary plans for redistributing surface waters to control flooding, facilitate drainage, provide for irrigation, and prevent sea-water encroachment. Current estimates indicate that construction costs in excess of a billion dollars would be required to develop an initial 2.1 million hectares (5.2 million acres) of the Delta to maximum economic potential; these costs do not cover those for upstream projects upon which the Delta developments depend.The Mekong Delta is underlain by an upper section of Recent alluvium, and a lower section of older alluvium. The older alluvium contains a permeable artesian zone called the 100-meter aquifer, which is the most productive groundwater reservoir in Viet Nam. Tested well capacities range from about 145 to 635 gallons per minute (gpm); more efficiently designed wells should produce in the range of 500 to 1,000 gpm from this aquifer. Part of the 100-meter aquifer is intruded by sea water.Current data permit no more than speculation with regard to storage, recharge, and flow in the 100-meter aquifer. Storage is estimated to be approximately 30 million acre-feet in the lower Delta, where the total dry season irrigation requirement is about 1.2 million acre-feet. Piezometric levels in the Delta wells may be due merely to sea-water pressure gradients acting across a horizontal saline-fresh-water interface; they do not necessarily imply ground-water flow or an area of recharge.A major inconsistency exists in the relation of certain reported piezometric levels and corresponding depths to well intakes assuming conditions of either hydrostatic or hydrodynamic equilibrium, and it is necessary to postulate special circumstances to account for this. The data also indicate conditions conducive to subsidence, although no evidence for subsidence has yet been observed.The most feasible plan for development of the Mekong Delta may involve the conjunctive use of surface water and ground water of the 100-meter aquifer, even though induced recharge and a ground-water barrier against sea-water intrusion might be necessary. Storage capacity is adequate, but more information is needed on recharge and total obtainable well capacities for the 100-meter aquifer and on the possibilities for occurrence and control of subsidence in the event of widespread ground-water development.

Notes: An investigation was made of infiltration conditions in the alluvial-filled Mad River valley in the vicinity of the Springfield municipal wells. The study shows that most recharge to the 100-foot thick sand and gravel aquifer is from induced infiltration from the Mad River. Local precipitation and natural, down-valley underflow also are important in sustaining the 14 mgd (million gallons per day) pumping rate.The investigation was designed to learn more about rates of streambed infiltration. Gaging stations were established at points above and below the well field in the expectation that infiltration losses could be measured directly. The attempt was unsuccessful because infiltration losses proved too small to measure accurately by ordinary stream gaging methods. The investigation has, nevertheless, provided much new data about this important watercourse aquifer system.Observation-well records covering the 4-year period 1965 through 1968 show that ground-water levels follow an annual cycle, typically rising in the period February through June, when recharge exceeds depletion, and falling during the remainder of the year. The rate of induced stream infiltration is not sufficient to prevent perennial dewatering of the aquifer beneath the streambed. The water table beneath the center of the losing reach ranges in depth from about 17 feet in January to about 6 feet in June in the average year. Bedrock highs beneath the stream, which result in local thinning of the aquifer upstream and downstream from the well field, essentially limit infiltration to a reach about 2½ miles long having an area of approximately 24 acres. During the 7-month depletion period average infiltration is estimated at 9 mgd and during the 5-month accretion period estimated infiltration is 12 mgd. On the basis of these estimates the infiltration rate for the respective periods is 0.37 and 0.50 mgd per acre, or about 0.35 mgd per acre per foot of depth.

Notes: Under steady state conditions of flow, the seepage toward a single gravity well is governed by the Laplace Equation which may be written in terms of either the hydraulic head, the pressure head or the velocity potential. Although this equation is linear, the principle of superposition cannot be applied to sum up the individual effects in the case of a multiple gravity well system due to the variation of the flow domain under the effect of one or several wells. A method is presented allowing the use of the superposition principle in a restricted form. The superposition of the decrements of the base pressure heads than the initial heads before pumping is valid. Also the decrements in the areas of the pressure head diagrams across specific vertical sections than the original areas can be summed up together.The limitations of Dupuit's well formula are explained. The validity of that formula has been proven on the basis of the analysis of the hydraulic forces within the flow medium, an approach which is different than that given by Hantush and Charney. Furthermore, the derived equation is written in terms of the areas of the pressure head diagrams across vertical sections and termed as the Unified Well Formula because it has been proven that the same formula is also valid for artesian wells.The analysis of the hydraulic forces leads to the development of an equation for the free surface. This equation is then solved numerically in one iterative cycle. Due to the lack of simple available solutions, only one case, previously solved by the relaxation techniques, is compared with the presented method. The maximum percent difference in the depth of saturation within 82% of the flow region does not exceed 3.2% whereas in the remainder 18% of the flow region around the well, the percent difference varies between 2.63% to 4.67%. Even these differences do not really indicate actual errors due to the approximation implied in the relaxation method itself using a coarser grid.This distribution of the hydraulic head across a vertical section is assumed parabolic. Although Polubarinova-Kochina presented a mathematical proof which leads to the same conclusion, yet for the reasons explained in the text, the writer preferred to use this type of distribution as a valid physical assumption.The results of the analysis of each single well are applied to determine the pattern of the interference between several gravity wells. By means of the presented approach, the resultant values of the depths of saturation can be obtained on the basis of the explained restricted procedure, of superposition. The hydraulic potential distribution within the flow medium of a multiple gravity well system can also be obtained. The assumption of the parabolic hydraulic head distribution is maintained in analyzing a group of wells. It is recommended to establish a proper computer program covering a grid system that encompasses all the wells and their individual influence regions in a certain well field.In the entire analysis, Dupuit's assumptions are eliminated. However, the two main assumptions in the given analysis are: (a) the parabolic distribution of the hydraulic head across a vertical section within the flow medium, and (b) the elimination of the circumferential velocities. These two introduced assumptions are -i in the writer's opinion – practically valid.

Notes: Carbonate aquifers with highly developed anisotropic permeabilities and other fractured rocks under water-table or semiwater-table conditions present complex hydrologic settings in which to predict the sustained yield of individual wells or groups of wells. Yields of wells in these settings are particularly responsive to the position of the water level and its relationship to one or more producing zones. Often a well's total capacity may be accounted for by one or more openings encountered in drilling which are separated by varying thicknesses of essentially nonproductive rock. A well s yield is determined more by the position of the water table with respect to these openings than to the proportion of saturated rock penetrated by the well bore.A permeability profile must be defined for. these wells along with their available drawdown, and the inclination of water-yielding openings. Permeability profiles may be roughly estimated from detailed driller's logs and caliper logs, and more precisely determined from flow meter surveys; packer tests and by pumping wells after successive increments of drilling or by a combination of increasing casing lengths and extended drilling. Available drawdown is dependent upon the inclination and position of significant water-yielding openings exposed within the bore hole and seasonal variations in the water-table position. In gently dipping carbonate rocks openings may follow bedding planes or selected beds favoring conduit development. Where this is known to be the case, pumping levels may be allowed to approach the top o.f one or another of these zones depending upon which is most productive.Where openings‘are inclined, pumping levels should be kept well above the depth at which the opening was penetrated to minimize the risk of dewatering conduits where they occur higher in elevation adjacent to the well bore compared to where they were penetrated by the well bore, Test holes may be drilled immediately adjacent to the potential production well to define the inclination of individual conduits or wells test pumped when possible at rates sufficient to draw the pumping level to the top of the opening in question. The latter is preferable because reductions in yield can be observed directly as a function of drawdown. To determine available drawdowns in fractured rocks, a permeability or yield profile, the inclination of openings adjacent to the well and seasonal variations in water levels must be known.

Notes: A field experiment has been installed near Firebaugh in the San Joaquin Valley of California to test submergence of drains as a means of denitrification of ground water. Laboratory and field experiments have shown that denitrification occurs in saturated soil where there is ample organic carbon available for bacterial metabolism. Denitrification and dilution of high nitrate ground water were accomplished in the field.

Notes: As round-water research is accelerated and basic data on aquifer parameters become more abundant, a statistical approach to evaluation of the ground-water regimen becomes increasingly useful. One such statistical technique is the fitting of polynomial trend-surfaces to ground-water levels. Barcholomew County, Indiana was chosen as a test site to derive techniques which could give additional guidance in the selection of areas suitable for the development of future ground-water resources.Trend-surface maps and maps of the deviations from the trend-surfaces were prepared from water-level data and evaluated to establish their relationships with the hydrogeologic regimen. A field-testing program was carried out to evaluate aquifer parameters.On the basis of the results obtained from these studies, the following conclusions were drawn:〈list xml:id="l1" style="custom"〉1A mathematically fitted surface may be considered to approximate the water-table or piezomecric surface, and will be sensitive to fluctuations in the ground-water reservoir.2The anomalous areas of the trend-surface represent local effects superimposed on the regional base and may be explained by a particular set of geologic, hydrologie or man-made conditions.From these conclusions, it appears that trend-surface analysis provides a rapid, inexpensive method of delineating attractive areas for detailed ground-water investigations.

Notes: Accurate measurement of static water levels in wells tapping deeply buried aquifers and aquitards at the Nevada Test Site requires evaluation of and correction for several factors exclusive of instrumentation. Both the drilling method used and the depth of the hole at the time of measurement significantly affect determination of the static water level for the aquitards, and frequently these factors preclude head determination in an economically justifiable time. Density of fluid in the drill stem and hole deviation affect the determination of accurate static water levels for the aquifers. In the principal aquifers, in which hydraulic gradients are as low as 0.5 foot per mile, direct measurement of depth to water is preferable to pressure-gage measurements at the aquifer face. Case histories and graphs are presented to illustrate the magnitude of errors that can result when these factors are disregarded.

Notes: The purpose of well screens and gravel packs is to maintain open access within the aquifer ensuring that thorough development of the well is not impeded by sand. Where a well draws on unconsolidated sands and gravels, or other friable materials, the installation of a screen and pack is essential.The use of correctly designed equipment is important and this paper represents a review of the diverse types available, but does not set out to make any recommendations.Well screen designs should incorporate the following features:〈list xml:id="l1" style="custom"〉1Minimum entrance velocity.2Maximum open area of screen.3Correct design of slots to minimize blockages.4Slot size should match aquifer or gravel pack medium.5Screen material should be corrosion resistant.6Screen should allow for periodic maintenance.Commercial well screens fall into various categories according to their slot designs. A slot shape, offering the maximum open area consistent with strength, is a priority and the material used in screen manufacture has an important bearing on this. Blockage of screens may be caused by chemical deposition formed by precipitation or corrosion products, and coated screens have been introduced seeking to inhibit this.Gravel packs should include the following design features:〈list xml:id="l2" style="custom"〉1Sand free operation after development.2Give lowest possible resistance to permeation.3Offer low entrance velocities.4Be resistant to chemical attack and have an efficient service life.The gravel pack should ensure that the completed well operates free of sand; thus the particle size of the pack depends upon the particle size of the aquifer. Gravel pack design should be guided by standard sieve analysis.It is evident from the variety of claims made for well screens and gravel packs that further research is necessary. It is suggested that the following points need further investigation:〈list xml:id="l3" style="custom"〉•. Improved design of nonblocking opening.•. Design consideration of screen resistance to chemical attack.•. Best type of gravel and optimum thickness of the pack.•. Head loss through the screen and pack.

Notes: Theoretical analyses predicted and experimental observations—confirmed a mechanism by which strong capilary forces hindered instead of helped promote infiltration into soils. Infiltration into an unsaturated soil overlying an impermeable barrier displaces the air from the soil interstices. Unable to escape downward, the air may escape upward in bubbles travelling through large pores, or, if the pores are small and the capillary forces are large, the air is compressed between the wetting front and the barrier. This reduces the infiltration rate and may result in an almost stable wetting front. Under certain calculable conditions the air pressure build-up is sufficient to cause sudden localized horizontal rupturing of the soil at the wetting front and to lift it along with the infiltrating water, forming a cavity. The air-filled cavity breaks the flow passages and percolation ceases through pores terminating in the cavity. Observations with soil columns have shown that when provision was made fot the displaced air to escape less than one minute was required for the wetting front to move three inches; when the air was not free to escape and the soil raptured, two weeks were required for the wetting front to move this distance. Grain size and packing play a role by limiting the capillary pressure build-up and the bubbling pressure. This phenomenon should emphasize precautions to be followed in applying laboratory infiltration results to engineering predictions of field conditions.

Notes: Results obtained from a linear programming ground-water management model are tested against those obtained using numerical and electrical analog ground-water models. The optimal distributions of pumping and head as predicted by the management model are verified.An improved optimal solution could be obtained by reformulating the management model using different constraints or a finer grid spacing.

Notes: DuPage County, one of the major counties of the Chicago metropolitan area, obtains all of its water supply from ground-water resources. In 1972, pumpage was 56.6 mgd, 18 percent more than the combined potential yield of shallow aquifers and the practical sustained yield of deep aquifers. Total pumpage from shallow aquifers almost equals the potential yield. In some areas, yields of shallow wells have declined drastically as a result of excessively heavy pumpage. Pumpage from deep aquifers is more than double the practical sustained yield. Demands for water are projected to increase more than 250 percent by the year 2020. Alternative methods of developing supplies to meet the anticipated demands include artificial recharge of shallow and/or deep aquifers, mining of deep aquifers, increased diversion of water from Lake Michigan, demineralizing Mt. Simon sandstone water, and importation of underdeveloped surface or ground-water resources in north central and northwestern Illinois. Increased coordination of development programs becomes of greater importance as locally available supplies lose the capability to meet growing demands.

Notes: The alluvial aquifer underlying and adjacent to the Mojave River near Barstow, California, has been subjected to degradation from percolation of industrial and municipal wastes for more than 60 years. Effluents discharged to the aquifer have contained high concentrations of both organic (detergents, oil and grease, phenols, humic compounds, and others) and inorganic (chromium, chloride, phosphates, and others) substances. The concentration of dissolved organic carbon (DOC), as determined by a wet combustion technique, has been shown to be a definitive parameter in identifying ground water affected by waste disposal. DOC concentrations ranged from 0.1 to 0.8 milligram per liter in the nondegraded ground water and exceeded 6 milligrams per liter in the ground water affected by the waste discharge.The general distribution of DOC in the degraded ground water has been defined both areally and vertically. The vertical distribution of DOC and other constituents indicates that two plumes of degraded water occur at different depths. A comparison of the areal distribution of DOC and detergents (as MBAS) suggests that some organic compounds may have been adsorbed by the aquifer sediments.

Notes: Analytical data for 161 sampling sites indicate orthophosphate concentrations in ground water ranging from 0 to 1.7 mg/1. Ground water in about 50 percent of the county contains concentrations of 0.1 mg/1 or greater. In two areas aggregating 115 square miles, orthophosphate concentrations exceed 0.5 mg/1. Principal sources of phosphate in ground water in Hall County include: indigenous soil phosphate, municipal sewage effluent, commercial fertilizer, and feedlot wastes.

Notes: In areas of crystalline and basaltic rocks in India dug wells of large diameter may offer the only opportunity to test for the hydrologic characteristics of the shallow aquifers. Analysis of aquifer tests in these wells is difficult, however, if the volume of water stored in the wells contributes significantly to their discharge during the tests. In most dug wells, the time rate and spatial distribution of drawdowns in the aquifer, and the rate of change of head in the dug well are not predictable by the Theis equation or its semilog modifications. High rates of pumping result in difficulties due to the insensitivity of head distributions to drawdowns in the well.A review of current methods of analysis of aquifer tests in large-diameter wells indicates that most have serious theoretical and practical deficiencies. It is concluded that the methods of Papadopulos and Cooper (1967) and Papadopulos (1967) are the best available approaches, providing measurements of well volume can be made with sufficient accuracy. A consideration of aquifer tests in fractured rocks suggests that these tests can probably best be handled by treating the aquifer as an anisotropic porous medium on a macroscopic scale and utilizing observation wells.

Notes: To aid in determining the direction of ground-water flow after the effluent from the Lake George Village sewage treatment plant is discharged onto natural delta sand beds, resistivity studies were made in the soil (sand) in the vicinity of the recharge beds. Ground water having high dissolved solids is identified as producing lower resistivity readings. The sewage effluent has a higher dissolved solids content than the existing ground water in the area. The path of the recharged sewage effluent, as identified by lower resistivity readings, appears to flow in a northerly direction from the sewage treatment plant along Gage Road toward West Brook. Due to interferences, the resistivity studies could not show whether the high conductivity ground water flows into or under West Brook.

Notes: Practically all of the toxic chemical land disposal sites now in operation are equipped with only minimal and generally ineffectual monitoring systems, which seldom are capable of detecting even excessive surface-water and ground-water pollution from such sites. From monitoring data normally obtained, it is practically impossible to quantitatively evaluate the total toxic chemical buildup in contiguous soil, plant, and water environments or the vertical and horizontal migration patterns of pollutants through underlying earth materials. Monitoring facilities and procedures described in this paper are designed to provide that data required to effectively evaluate all of these parameters. These evaluations in turn should be most helpful in selecting the safest possible sites for hazardous waste disposal, and in developing ways and means to design, operate, and monitor such facilities that will assure minimal danger to public health from this particular waste disposal practice in the future.

Notes: Aquifers may serve as storage reservoirs, as treatment mediums, as discharge conduits, or in some combination of the various uses. If an aquifer serves as a conduit, the Darcy equation gives an accurate and simple solution for discharge provided the conduit is uniform; if nonuniform, the accuracy may be very poor unless special care is taken.Differential equations based on Darcy's equation and the equation of continuity give the steady-flow discharge rate for confined aquifers in which the cross-sectional area and permeability vary from point to point. For the general case the derived discharge expression is theoretically exact, whereas, for specific cases an approximate form can be used depending on the boundary conditions. Integration of the approximate form for a given aquifer length yields simplified solutions for discharge where the variation in cross-sectional area and/or permeability with distance in the direction of flow can be described by some mathematical expression.

Notes: Contemporary use patterns of land and water resources create conflicts between natural and human environments. These conflicts are generally not discussed as part of a classical approach to geologic education. This paper addresses the need to increase non-earth science training simultaneous with traditional training. The benefits to be gained will be welcomed by both students and their potential employers. One approach to suggested interdisciplinary water-resource education is discussed.

Notes: Low-rate or irrigation-type systems for land application of sewage effluent or similar wastewater are often used in humid areas because they have a small impact on the underlying ground water. In arid areas, low-rate systems cannot be used to produce renovated water for ground-water recharge, because the renovated water will have a much higher salt content than the effluent. Renovated water of relatively low salt content can only be produced with high-rate systems. Such systems, which require permeable soil, can also be used in humid areas to reduce the land requirements. To minimize the impact of high-rate systems on ground-water quality, the system should be managed to remove as much of the pollutants (particularly nitrogen and phosphorus) as possible from the wastewater as it seeps through the soil, and to restrict the spread of renovated wastewater in the ground-water basin. Nitrogen removal can be maximized by stimulating denitrification in the soil. Certain soils can store large quantities of phosphate. The spread of renovated water in the ground water can be controlled by intercepting the flow of renovated water with wells or drains for reuse or discharge into surface water. Techniques for predicting the underground flow system are presented.

Notes: Bore hole sampling of loose saturated sands and gravels forms a very important part of water well investigations. The materials are often difficult to sample and the adoption of adequate equipment and techniques can sorely tax the ingenuity of the driller.In some situations, the standard exploration sampling procedures can provide satisfactory information, while in others, it is necessary to resort to more precise techniques.A great variety of samplers have been designed including types such as open drive, piston drive, jet and extension flap samplers. No single sampler can cover the very wide range of material conditions and operational requirements which may be met during the drilling of water wells.In extreme circumstances, particularly for uncemented or poorly cemented gravels, it may be found necessary to stabilize the strata prior to sampling.

Notes: When the Lake George sewage treatment plant was put into operation in 1939, it was described as a “complete treatment” plant. This was because the treated effluent is discharged onto natural delta sand seepage beds which are “at least 25 feet deep.”Studies were made to determine the removal efficiency in the sand beds of coliforms, BOD, chlorides, and the nitrogen and phosphorus compounds.It was found that when beds were dosed, they were no longer saturated with water at 15 feet. Ten feet of sand were found to remove coliforms by 99% and BOD by 96%. However, nitrates, phosphates, and chlorides remained in significant concentrations after filtration through 10 feet of sand. Phosphate removal in an infrequently used sand bed was greater than in a continuously used bed.

Notes: At the Savannah River Plant near Aiken, South Carolina, as at other locations where there are chemical separations plants for the processing of nuclear fuels, the high-level radioactive wastes are stored in concrete and steel tanks buried just beneath the surface of the ground. This waste is of such activity and longevity that it cannot be dispersed into the environment, but it must be contained for periods of time extending at least into hundreds and perhaps thousands of years. One concept for the terminal containment of this waste is to store it in excavated chambers within the bedrock, which is covered by about 1000 feet of Coastal Plain sediments at the plantsite. As part of the safety evaluation of this concept, the geology and hydrology of both the Coastal Plain sediments and the bedrock have been studied. However, intensive investigation of bedrock waste storage has now been deferred pending more detailed evaluation of alternative concepts of waste storage and management.In the studies completed, a buried Triassic basin that might have potential for waste storage was discovered beneath the southern third of the plantsite. Investigation into the characteristics of this basin was started in 1971. This was not an engineering or design study but was aimed at understanding the geohydrology of the Triassic basin to determine its compatibility with the safe storage of waste.Seismic surveys, gravity and magnetic surveys, and the drilling of several exploratory wells indicate that the Triassic basin is about 30 miles long, 6 or more miles wide, and perhaps 5300 feet thick. One well penetrated the Triassic border, a second was in the center of the basin, and a third investigated an inferred intrabasin fault. The rock is predominantly mudstone of very low permeability with a few lenses of poorly sorted gritty sand. The water yield of all the exploratory wells is extremely low, and water-transmitting fractures are virtually nonexistent.In two wells within the basin, heads above land surface have been measured that cannot be explained by connection with a recharge area. Ten possible explanations have been evaluated: aquifer head, fossil head, tectonic compression, rapid loading and compaction of sediments, water derived from igneous intrusions, infiltration of gas, precipitation of minerals, phase changes, temperature increase, and osmotic membrane phenomena. Systematic evaluation, particularly of the time for dissipation of an elevated head to the head of its surroundings, eliminates most of these explanations. Those that remain as possible explanations are: tectonic compression, temperature increase, and osmotic membrane phenomena. It is not known at present whether the high head is general over the entire basin or only in segments of it.

Notes: Many tube wells drilled for irrigation use fail prematurely because of poor well design, improper sized and placed gravel-pack material, and ineffective slotted-pipe screens. Well and gravel-pack design criteria and an improved slotted-pipe screen described in this paper offer promise of drastically reducing such failures. Properly designed tube wells equipped with this type of screen should have more than double the safe-yield and service-life capability of most irrigation tube wells now in use.In some countries large-diameter, low-capacity open wells always have been used to obtain irrigation water. Now, small-diameter, high-capacity tube wells are being constructed in the same aquifers. As extensive tube-well development occurs, the water table will drop, drying up many shallow open wells. In such instances, those who can afford the deeper, more expensive tube wells could gain almost exclusive use of the aquifer.Optimum development of surficial aquifers using both tube and open wells may have to be rigidly controlled to assure every farmer a fair share of available water. Such controls should be based on the potential safe yield capability of aquifers. A graphical procedure used in Illinois to obtain an estimate of this value for planning and initial development purposes is presented in this paper.

Notes: A mathematical model was developed and used to simulate the stream-aquifer system in the Arkansas River valley in southeastern Colorado, from Pueblo to the Colorado-Kansas State line. The model simulates the interrelations among ground water and surface water including reservoirs, losses, and transmountain diversions, utilizing various water-distribution rules. The model was used to analyze 24 water-management plans designed to reduce shortages in the irrigation supply. One management plan simulated salvage of water from phreatophyte evapotranspiration, different reservoir operation regulations, use of imported ground and surface water, a new reservoir, additional ground-water use, and application of excess streamflow. The resulting annual dependable supply was increased from 610,000 acre-feet to 870,000 acre-feet in relation to an annual demand of 1,100,000 acre-feet. The model can be used as a tool to analyze other water-management plans.

Notes: The “kaolinic porridge” is described as one of the saturated zones within the weathering profile of most igneous and metamorphic rocks in Ghana. The zone is comprised of clay and fine-grained micaceous materials and is regarded as an important ground-water reservoir. Due to its fluid nature and the fact that its depth and thickness cannot be predicted, precautionary measures are taken when drilling. Special well design, construction and completion techniques have been adopted to exploit this aquifer successfully. Yields averaging 220 gallons (about 1 cubic meter) per hour can be produced from such aquifers.

Notes: The sheetlike solution cavities that supply water to most wells in central Tennessee are 100 to 2,500 feet wide and less than 0.2 inch high. These dimensions have a scale similar to those in Hele-Shaw models. Both logical and mathematical evidence indicate laminar ground-water flow, except close to pumping wells. The Theis nonequilibrium formula may be used to analyze aquifer-test data and to calculate significant values for transmissivity and storage. The Navier-Stokes equation and the Darcy equation for steady-state conditions may be used to estimate cavity dimensions.

Notes: A solution is obtained for drawdown around pumping wells in aquifers near streams in the presence of delayed yield from storage using the image theory. Two methods (the second one with two variants) are presented for determining the aquifer constants. The first method is based on the type curves for the initial moments of pumping and for later ones. The Carson-Laplace transforms of drawdown field data are required for applying the other method. A field example Ts used for illustration.

Notes: Hybrid wells (a type of collector well) offer a method of increasing the specific capacity of a deep well. A regular deep well is combined with a gallery constructed similar to the qanats, a labor-intensive technology found in the Middle East. Qanats, tunnels that tap ground water for water supplies, are described. The author explains: (1) the method of constructing hybrid wells, (2) some theoretical considerations using the nonequilibrium equation for pumping tests and the Donnan equation for drain design, and (3) the economic gains from hybrid wells.

Notes: Wastewater disposal by a combination of soil infiltration and evapotranspiration is better than disposal through centralized sewerage systems, because the first alternative returns wastewater nutrients where they belong—to growing plants—rather than discharge the pollutants where they cause damage through eutrophication of lakes and rivers, as the second alternative does.Wastewater disposal by soil infiltration and evapotranspiration achieves advantages for our much abused environment only if three conditions are met: (1) sufficient land area is available, (2) strong microbial activities are evident, and (3) water-supply wells are protected.The proposed method for design and area calculation of seepage beds stresses—in addition to the quality of soil—the importance of microbial actions to keep the soil pores open. For silt-loam-clay mixtures of soils, the required seepage bed area varies from 365 sq ft (34 m2) to 640 sq ft (60 m2) for average households if actions of higher aerobic microorganisms are strong.Water-supply wells located on the same property are protected from wastewater contamination by natural purification in deep layers of undisturbed soil. The protective distance between mouth of well and seepage bed has a vertical and a horizontal component, the former determined by the depth of the well. The need for a sufficiently long horizontal component influences the required property size. It also depends on the types of soil at deeper layers. For an 80 ft deep well for example, the horizontal protective distance varies from 80 ft (24 m) for silt-loam mixtures to 140 ft (42 m) for sand-silt mixtures.Wastewater can be entirely evaporated, if soil infiltration would be a hazard to water-supply wells. Evapotranspiration beds of 2000 sq ft (186 m2) with strong microbial activity are needed for average households.

Notes: Ground-water irrigation has developed rapidly in the High Plains region of the United States, especially in Texas since the 1930's and more recently in western Kansas. Although most land sales transactions do not show the water value separate from the dry land value, the availability of ground water has greatly affected land values. This study measures this effect by two methods for an area of southwestern Kansas where ground-water irrigation has become important.The purchasers of all farm land sold in the selected area between 1962-67 were surveyed to obtain information on sale price and numerous factors which it was thought might have a bearing on the land value. One method of measuring the effect of ground water on land value involved matching a number of tracts not known to have available ground water for irrigation with an equal number having ground water. Since other factors were matched as closely as possible, the differences in land value were attributed to water. The second method was multiple regression in which total tract land value and land value per acre for some 160 tracts were related to several factors–soil and topographic conditions, tract size, availability of ground water for irrigation, nearness to elevator, mineral rights, and wheat allotment. Both methods produced approximately the same results–for the period studied the availability of ground water for irrigation contributed $95 to $100 per acre to the value of the land.

Notes: In the Rothschild area, Wisconsin, most water wells are completed in glacial deposits. When glacial deposits are unsaturated or thin, wells are completed in fractured crystalline rocks of Pre-Cambrian age. Specific capacity data from 56 wells tapping these fractured rocks reveal:〈list xml:id="l1" style="custom"〉1Yields and specific capacity are generally small, with a median specific capacity of log 0.17 gpm/ft and a mean value of log 0.10 gpm/ft.2Wells which are close together may have substantially different specific capacities.3The occurrence of saturated sand and gravel above the crystalline rocks has no obvious influence on yield or specific capacity.4Specific capacities of wells seem to be inversely proportional to (a) thickness of rocks penetrated below the water table, (b) depth of the wells below the water table, and (c) depth of the wells below the land surface.Assuming that specific capacities of wells are related to the number of contributing fractures penetrated and that the number of fractures diminishes linearly with depth, the following relation is derived: 〈displayedItem type="mathematics" xml:id="mu1" numbered="no"〉〈mediaResource alt="image" href="urn:x-wiley:0017467X:GWAT37:GWAT_37_mu1"/〉 where Sc= specific capacity, Q = discharge, s = drawdown, B = a constant, b = fracture frequency at the land surface, z = depth, and E = maximum depth of fracturing. In the Rothschild area, E = 100 feet.In exploring for ground water in a fractured rock, the problem is to find the area of maximum b. If sound scientific methods are not available, then exploration will consist of drilling wells at random until a satisfactory well is completed. However, because wells achieve 60 to 80 percent of their yield in the first 20 feet below the water table, test wells should be pump tested when they have reached a depth of about 20 feet below the water table. Unsuccessful wells need not be drilled to completion.

Notes: Despite rainfalls which commonly exceed 200 inches per year in the mountainous portions of many of the islands in the Hawaiian chain, most streams in the islands are very flashy, and only a few carry water throughout the year. This is owing to the extremely permeable nature of the volcanic rocks and soils which make up the Hawaiian islands, and, in fact, the permeability of some of the younger volcanic rocks is so great that virtually no runoff occurs. As a result, development of reliable year-round sources of surface water is difficult especially on the leeward portions of the islands. Furthermore, surface storage is difficult because of the high infiltration capacities of the rock and soil cover. Consequently, development of ground water provides the most abundant and the most reliable source of water supply for these islands. Three modes of fresh ground-water occurrence may be distinguished: perched, dike-confined, and basal. Although perched and dike-confined ground water are of considerable local importance, the basal ground-water body is by far the most widely developed and most important source of fresh ground water for these islands.

Notes: This is the second part of a two-part series (Kent and Sendlein, 1972) in which an approximation of the quantity of bedrock recharge is made. Procedures used for the definition of the ground-water system were described in Part I. In Part II, a subsurface ground-water budget equates subsurface recharge from the bedrock aquifer to discharge through sand and gravel and to discharge by pumping. The Darcy equation is used to compute recharge and discharge volume flow rates. Estimates of permeability were obtained from existing pump-test data and the hydraulic gradients were determined from the piezometric map. Two conceptual models are proposed to account for the maximum and minimum cross sectional areas of the bedrock aquifer through which ground water could flow into the sands and gravel and thus are used to represent the maximum and minimum limits of recharge. Upper, lower and average values of bedrock recharge are determined for each model and compared with the average natural discharge for the entire ground-water basin (“total basin” approach). Comparisons are also made for portions of the basin (“partial basin” approach). Upper and lower limits of recharge are chosen from recharge values which are nearest to the average discharge estimate. This determination is based on the assumption that recharge is equal to discharge. Results of this study indicate a quantity of bedrock recharge between a lower limit of 0.23 mgpd and an upper limit of 2.5 mgpd is possible for an 800-square mile basin.The purpose of this approach is to provide an approximation of ground-water recharge from bedrock into an unconfined unconsolidated ground-water basin, and to provide an estimate of its importance to urban ground-water use.

Notes: Book Reviewed in this article:WATER PUBLICATIONS OF STATE AGENCIES complied by Gerald J. Giefer.

Notes: The disposal of all types of liquid and solid wastes threatens the health and well-being of mankind. In recent years the constraints on the disposal of industrial and municipal wastes into rivers and the seas have prompted the disposal through wells into the subsurface. Limestone terrane is particularly amenable to the acceptance of all types of wastes in the cavernous subsurface, and has resulted in widespread contamination of shallow ground-water resources. Highway salting has caused the contamination of thousands of household wells, causing large-scale replacement drilling programs in some northern States. A semantics problem also has arisen, because liquid wastes injected into the subsurface have not been disposed of, but rather have been placed in a new environment. They may be in storage, they may be attenuating, or they may be changing character by reaction with the rock mass or formation fluids.The U. S. Geological Survey has been concerned with the study of ground-water resources for more than 80 years, and with the problems of radioactive waste contamination since World War II. A newly identified program of investigations of waste emplacement into the subsurface was begun two years ago. The purpose of the program is to develop the ability to predict the fate of any wastes deliberately or accidentally emplaced in the subsurface. The program includes research contracts and grants with universities and governmental organizations as well as in-house research.

Notes: In the formerly glaciated Midwest, bedrock formations commonly are denser than overlying glacial sediments. Thus, gravity anomalies have a direct relationship to bedrock topography. Where the density contrast between the glacial sediments and the bedrock is known, the anomalies can be used to map the bedrock configuration if they can be isolated from gravity anomalies originating elsewhere in the geologic section. A method of isolating bedrock topography gravity anomalies is suggested based upon known bedrock elevations obtained from drillhole data. A regional gravity anomaly map is prepared by subtracting the excess gravitational effect of the known bedrock relief above a datum from the observed gravity anomalies at all drillhole sites. The regional gravity anomaly map is subtracted from the observed anomaly map to obtain a residual anomaly map reflecting the bedrock topography. The bedrock configuration can be calculated directly from this map. This method of isolating bedrock topography anomalies was found to be superior to the use of cross-profiling and least-squares polynomial approximation procedures in a study of Kalamazoo County, Michigan. The bedrock topography map of this County determined by the gravity-geologic method shows a complex bedrock topography and drainage system.

Notes: If there are gravity data and some geological information available from the region of an intermontane basin, then the volume of saturated sediments, volume of ground water available from storage, and the total volume of ground water can be determined from the gravitationally determined anomalous mass. The anomalous mass occurs because of a density contrast which exists between low density alluvium and high density bedrock which define the surface and subsurface boundaries of the basin. The gravity effect of the anomalous mass can be detected by a gravity survey of the basin after which it can be separated from other gravity effects by a regional-residual separation. The anomalous mass is uniquely determined by applying Gauss's theorem to the residual gravity map.A model of an intermontane basin is developed which relates the anomalous mass to the total volume of saturated sediments. The total volume of saturated sediments is determined from the anomalous mass, the density contrasts between unsaturated and saturated alluvium and bedrock, the area of the basin, and the water table depth.The volume of water available from storage and the total volume of water in the basin are determined from the volume of saturated sediments and the storage coefficient and porosity of the sediments.The method is illustrated by a case history from Avra Valley, Arizona. It is concluded that the major advantage of this method occurs when well data are not available, because it eliminates the need for arbitrary assumptions about subsurface basin geometry to determine the volume of saturated sediments.

Notes: This paper presents some of the preliminary results of a theoretical analysis of the ground-water infill rate of a rubble chimney produced by an underground nuclear explosion. The study was conducted to evaluate effects that various features of the hydrogeology regime have on rate of infill. This model for infill is based on the analogy of a rubble chimney to a small diameter gravity well. The infill history is approximated by integrating production from a series of steady state infill rates based on Dupuit-Forchheimer assumptions. The model has been used for parameter sensitivity analysis. Of the aquifer characteristics, changes of the hydraulic conductivity have the greatest effect on infill; the radius of influence is most sensitive to changes in the specific yield. The effect of infill rate of using a rubble porosity that decreases with depth is small, although initial infill is more rapid. The hydrogeology data from two events where infill data are available have been used with this model for verification. For both BILBY and GREELEY events, agreement between measured and calculated infill data are good. BILBY data suggest that substantial dewatering of the rubble in the chimney occurred before much ground water entered the chimney. Comparison of the GREELEY data indicates that dewatering of the rubble is minimal but that porosity of the rubble near the surface was higher than originally anticipated.

Notes: Leaching of heavy metals by ground water passing through mine tailings is caused by the oxidation of sulfides through the action of microorganisms. The pH of the ground water entering the tailings system is reduced by mechanisms within the tailings system itself. Action of sulfide-oxidizing and sulfur-oxidizing bacteria causes the formation of sulfuric acid, thereby increasing the H+ and SO42− concentration within the system. Metal ions go into solution as metal sulfates, and the concentration of H2S increases by the interaction of H+ and S2− Increase in H2S creates an environment suitable for the growth of sulfate-reducing bacteria which converts SO42− to S2− and simultaneously precipitates metal sulfides at a pH near 6.6. Decrease in pH with depth destroys sulfate-reducing bacteria, and dissolution and leaching of the tailings increase.Four lines of evidence demonstrate the presence of microorganisms in the tailings system: (1) Fe-Mn concretions below the water table at Cataldo Mission Flats, (2) fixation of Na and K below the water table, (3) precipitation of sulfate salts on the surface of Cataldo Mission Flats, and (4) experiments on two sets of tailings samples, one from the surface which showed predominant aerobic activity and one from below the water table which showed predominant anaerobic activity. Where oxygen is sufficient, iron oxidizing bacteria oxidize Fe2+ to Fe3+ which forms an insoluble hydroxide. Consequently, very little iron is found in the ground water coming from the system. The combination of these mechanisms produces poor-quality ground water with respect to metals.

Notes: Chemical analyses of natural water may be inadequate because of inadvertent human errors and sample aging. Characteristic deficiencies can be demonstrated by multiple chemical analyses of the same sample by different laboratories, multiple analyses of the same sample by one laboratory, repeated analyses of one sample as a function of time, and a simple laboratory experiment in rock-water chemistry. Whenever possible, complete chemical analyses should be made. The most reliable analyses are those in which combining weights of the cation equal the combining weight of the anion and in which the sum of the individually measured constituents equals the observed residue on evaporation at 180°C (total dissolved solids).

Notes: Corrosion and incrustation of water wells is defined and classified into groups which fit most field problems. Case histories with concomitant water analyses are described. A readily determined index for the magnitude of corrosion is presented along with recommended materials to correspond with the indices. The theory for the most common well incrustants is presented. Recommendations are made for minimizing the rate of incrustation in wells supplying water known to be incrusting and thus eventually clogging well screens. Treatments for incrusted wells are described including iron bacteria. A ten-year case history of iron bacteria fouling is presented. Nonmetallics are discussed.Descriptors: Well failures, corrosion of well components, incrustation of screens, water analyses, index, guide lines, nonmetallics, iron bacteria.Identifiers: Corrosion and incrustation problems in wells.

Notes: Standard resistivity configurations lose resolution in regions where multiple geologic layering of high conductivity contrast occurs. To partially circumvent this problem an electrode configuration was used, which includes a current electrode at depth down a drill hole in a water field, to examine the possibility of delineating ground-water flow channels. Results show the value of this technique in enhancing the electrical anomaly and hence determining structure. It was found that the ground water in this area flows primarily in fracture traces in the dolomite. Moreover, it was determined from well log synthesis that these fracture traces increase the effective porosity in the flow region by approximately ten percent.

Notes: Quality of water is determined by chemical analyses, the data from which are used for various purposes, such as classification, analysis, correlation, etc. For these purposes, the data need to be compiled and statistically evaluated. Graphical and numerical interpretation, a basic tool in hydrochemical studies, is one of the means used for summarizing and presenting water-quality data. There exist a considerable number of methods and procedures which can be applied. They are relatively simple and can be used without extensive knowledge of chemistry. Main techniques and methods are grouped, for the purpose of discussion, into four categories as to their possible use: classification methods, correlation methods, analytic methods, and synthetic and illustrative methods. The basic graphs and diagrams in each category are accompanied by examples.

Notes: A survey of State water agency and university personnel was conducted to identify and classify interstate and international aquifer problems in the conterminous United States. Questionnaires returned identified nearly 200 of such situations. Of these, 30 situations were classified as being a major problem at the present time. An additional 73 situations were classified as minor at the present time. For those problems that were indicated as being expected to develop within the next five years, 9 were classified as major and 25 as minor. For those problems that were indicated as being expected to develop after five or more years, 19 were classified as major and 42 as minor.

Notes: Appropriate nonparametric or distribution free statistical techniques are useful tools when data do not satisfy the conditions required by parametric statistical tests, and may be applied to a variety of hydrogeological problems. Two nonparametric tests, Krusk-Wallis One-Way Analysis of Variance and Mann-Whitney U Test, were used to test the significance of observed differences in well yields with respect to variation in controlling hydrogeologic factors. This paper presents the steps involved in performing these two tests with one example for each and suggests other applications to water-related problems. To avoid computational errors and save time, a computer program was written for calculating the statistics used in these tests.

Notes: Salty ground water is commonly encountered at relatively shallow depths of 100 to 300 feet beneath the major stream channels in the western half of West Virginia. Because of the wide distribution of salty ground water and connate brine at various depths, it is difficult to distinguish natural contamination from that caused by subsurface industrial activities. Natural changes in quality apparently are minor. The available historical data indicate no large-scale natural variations in salt content during the period of record. Histories of some water well developments show unnatural large-scale increases in salt content from various industrial activities that affect the fresh water zones. Some records also reveal decreases in salt content after the source of the salt was eliminated or after the subsurface activity responsible for artificial migration of the salt water was stopped.Artesian brine contaminated a fresh water aquifer in Fayette County. Chloride content changed from 53 mg/l to more than 1,900 mg/l in a period of 5½ years. When pumping was stopped, chloride content decreased to 55 mg/l in 10 years.Heavy pumping of well fields in Charleston during 1930 to 1956 accelerated migration upward of salt water. Chloride content increased from less than 100 mg/l to more than 300 mg/l in some wells and to more than 1,000 mg/l at individual wells. Pumpage has declined greatly since 1956 and chloride content has decreased below 200 mg/l at some of the contaminated wells.In an oil field of Kanawha County, a water well was contaminated by salt water accelerated by subsurface activities. Chloride content increased from less than 100 mg/l to more than 2,900 mg/l within 2 months. After the oil-field activity was curtailed, chloride content decreased to 190 mg/l in about 2½ years. Road salt piles contaminated a carbonate aquifer in Monroe County. Chloride concentrations in wells located 1,500 feet from the piles increased from 185 mg/l to 1,000 mg/l in 5 years. The greatest change was 1,000 mg/l in 1969 to 7,200 mg/l in 1970 when the salt storage area was enlarged. All salt piles were removed in late 1970 and within 2 months chloride content decreased to 188 mg/l.

Notes: The cathepsins in saline muscle extracts of three species of Pacific sole were investigated. A buffered hemoglobin solution (pH 3.0) served as substrate for the enzyme assay. No apparent change in catheptic activity in muscle homogenates of English sole was observed during 25 days of frozen (−26 °C) storage. Partial characterization of the cathepsins indicated a pH activity optimum of 3.0–3.5 for rex and petrale sole but a slightly higher PH optimum of 3.2–3.8 for English sole. The three species showed a temperature optimum of 45 °C for hemoglobin splitting. A wide variation in catheptic activity within the species was observed for rex sole while English and petrale sole showed more uniform catheptic activity. The mean activities for the three species varied significantly (P 〈 0.05). Results of sensory evaluation of muscles containing high and low levels of catheptic activity from the three species of sole did not support the assumption that cathepsins have a substantial influence upon the quality of marine food fish.

Notes: SUMMARY: The viscosities of selected fruit juices and purees were measured with a coaxial-cylinder viscometer in the temperature range 20–70°C. Depectinized apple juice and Concord grape juice were Newtonian fluids at all concentrations and their viscosity decreased considerably at higher temperatures. Cloudy apple and orange juices changed from Newtonian to pseudoplastic at concentrations higher than 50 and 20° Brix. respectively. Temperature had a smaller effect on viscosity of cloudy juices than of clear juices. The apparent viscosity of fruit purees (pseudoplastic fluids) decreased slightly at higher temperatures. The activation energy for flow increased with the juice concentration and decreased with the presence of suspended particles in the fruit product. The data and conclusions are useful in the design and operation of efficient food-processing equipment.

Notes: SUMMARY: A study of the physical changes associated with rigor mortis in breast muscle was undertaken to assess the factors that may influence ultimate tenderness. Isometric tension changes and shortening were measured at temperatures 2–37°C. These changes were measured while holding the muscle strips in a phosphate buffer, pH 7.2. Isometric tension was measured by transducers and recorded on a physiograph. A pattern of tension development and gradual relaxation has been demonstrated to occur post-mortem in strips of turkey breast muscle held isometrically. The time to maximum tension development occurs in 3.85 ± 0.19 hr and is not linearly related (P 〈.05) to temperature. The amount of maximum tension developed averaged 25 g/cm2 and was significantly (P 〈 .05) related to temperature. Relaxation to about 50% of maximum occurs in 18 hr. The amount of shortening that occurs post-mortem is linearly related (P 〈 .01) to temperature. No “cold shortening” of turkey breast muscle was evident.