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 With proper pumpage distribution it is conceivable that there is sufficient water that can be withdrawn (mined) in excess of natural recharge to meet demands through the year 2020.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: 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: A typical marl lake of the Upper Great Lakes region has very few quantitatively important aquatic macrophytes. The macrophytes, however, dominate the total primary production of the lake. Submersed vegetation is extremely sparse on the shallow (less than I m) marl bench that characterizes the littoral of these lakes, and is completely dominated by one. little-known species (Scirpus subterminalis Torr.) between 1 and 7 m.A detailed investigation of the spatial and seasonal distribution of macrophytic species and biomass showed that S. subterminalis strongly dominated the lake (79% of total biomass). S. suhterminalis represented an almost pure stand (to 200 g m−2 mean annual ash-free dry weight) at all times of the year at intermediate depths of macrophytic growth (1–6 m). Two species of Chara (of eight varieties and forms) were present in significant quantities (12% of total biomass; to 100 g m−2) but were severely limited to shallow depths (0-S-l m) and protected areas. Several annual submersed angiosperms were present (9% of total biomass), but only two species were quantitatively important. Potamogeton illinoensis Morong. and P. praelongus Wulfen formed brief summer peaks (less than 100 g m−2) at 3 and 4–6 m, respectively.A striking feature of the seasonal biomass distribution of Scirpus subterminalis was the higher, viable biomass (to 150g m−2) throughout the winter under ice cover. Cyclic fluctuations of the S. subterminalis populations were discerned at different depths, each with different periodicities. The population at 2 m exhibited a fall peak; that at 4 m had a summer maximum. The lowest overall biomass of S. subterminalis occurred in the 2 m population in June. Chara populations at 0–2 m also exhibited a relatively constant biomass throughout the year. The appearance of Nitella at 7 m in July-October and of Chara at 5 m in September-October was interpreted as an interaction between light, thermal, and carbon stratification.Estimates of macrophytic productivity of perennial (‘evergreen’) species populations whose biomass remains relatively constant throughout the year were made employing several different methods of calculation and turnover factors. All methods resulted in productivity estimates in good agreement with the conservative value of 178 g m−2 year−1 for the entire lake. In comparison to the other components (phyto-planktonic, epiphytic and epipelic algae) of the primary production of Lawrence Lake, the aquatic macrophytes constituted a major portion (anuual mean 82·77 g C m−2 year−1 or 48·3 %) of the total production of the lake.The low diversity but relatively high quantitative importance of macrophytes in marl lakes is attributed to an adverse dissolved inorganic and organic chemical milieu which inhibits phytoplanktonic production and allows only certain adapted macrophytes to develop strongly. The phenomenon of perennial biomass levels throughout the year is believed to be much more common than previously suspected and has iikely resulted from adaptations of submersed macrophytes to ameliorated conditions of water and temperatures relative to the terrestrial situation in winter.

Notes: Five species of helminth parasites were found in adults and tadpoles of the newts Triturus helveticus, T. vulgaris, and T. cristatus, caught at eight different localities in Somerset. These parasites were Acanthocephalus anthuris, A. ranae, Megalobatra-chonema terdentatum, Thominx filiformis and Oswaldocruzia molgeta. Mean worm burdens did not change through the year, and egg-producing females of Acantho-cephalus anthuris and Megalobatrachonema terdentatum were found throughout. There was no difference in the level of infection of male and female newts.

Notes: The paper presents information on factors influencing maximum feeding-rates (measured in the laboratory) in larvae of the damselfly Pyrrhosoma nymphula, and compares estimates of feeding rates in the field with maximum feeding-rates for larvae of the same size at the same temperature.Maximum feeding-rates in Pyrrhosoma larvae of different sizes were measured at 4, 5, 10 and 15°C. At low temperatures (4–5°C) maximum feeding-rate was depressed more than predicted either from the effects of temperature on the gut-clearance time of larvae or their respiratory rate. Maximum feeding-rate declined steadily throughout metamorphosis in the final instar and stopped completely prior to emergence of the adult.Feeding-rates in the field were calculated from ‘balanced’ energy equations, i.e. from the sum of larval growth, respiration and the production of faeces and exuviae. Feeding rates in the field were always much less than maximum feeding-rates for the same size of larva at the same temperature, and at the most were never more than 70% of the latter; they were closer to the maximum in summer than in winter, when they fell as low as 20% of the maximum.The relevance of these findings to studies on the efficiency with which carnivores utilize energy in the field, and the importance of Odonata larvae as predators in aquatic ecosystems is discussed.

Notes: Fewer species and more individuals of Tubificidae were present in the soft sediments of a polluted ditch than in the relatively unpolluted Bere Stream.Changes in width frequency of natural populations of Tubifex tubifex and Limno-drilus hoffmeisteri throughout the year were similar at both the sites investigated.In laboratory experiments larger populations of Tubifex tubifex developed in fine sediments than coarse. By means of a width-dry-weight relationship it was possible to estimate the weight of the experimental populations.

Notes: Several geophysical techniques have been specialized for applications to exploration for ground water in an insular basaltic environment. This article describes a multidisciplinary application of several such techniques to the Kona Coast of Hawaii in Hawaii. Aerial infrared scanning and low-level aeromagnetic surveys were the major reconnaissance techniques. For detailed study, modified audiomagnetotelluric and D. C. resistivity profiling methods were used. The improved knowledge of subsurface structure confirmed the expectation that no large flows, such as suitable for commercial exploration, occur in that coastal sector.

Notes: The Bureau of Reclamation's authorized Lower Teton Division multipurpose project is based on conjunctive use for irrigation of surface water from the Snake River and ground water from the Snake Plain basalt aquifer of southeastern Idaho. Ground water will be provided to replace surface water adversely diverted to Division lands during dry years. Extensive investigations, including the construction and testing of five test wells of 12- to 18-cubic-foot per-second (cfs) capacity, indicate that use of such large wells is feasible, and that the basalt aquifer will yield the initial 400-cfs maximum flow without appreciable detrimental effect. Location of well fields and design and construction practices were primarily controlled by field conditions; use of theoretical parameters was essentially precluded.

Notes: C. E. Jacob was the first of a small group of hydrologists who followed C. V. Theis’ lead in application of the theory of nonsteady boundary value problems to both well hydraulics and regional ground-water movement. Some of his scientific contributions were the explanation of the storage and elastic properties of artesian aquifers, the semi-log method of aquifer test analysis, methods of analysis of tests on unconfined leaky aquifers, application of doublet theory to paired polarized heat-pump wells, the theory of step and constant-head aquifer tests by wells, salt-water encroachment, the tutelage of hydrology students at several universities, solutions to hundreds of field problems encountered in his extensive consulting activities in many parts of the world, and his method of determining aquifer recharge and transmissivity from the response of water levels in wells to varying natural recharge. One of his last works was a study of the natural recharge to Southampton on Long Island, which showed that the recharge was much less than the 21 inches per year assumed previously.

Notes: The storage of both liquids and gases in underground strata has become rather common in Illinois.The problem of disposal of fluid industrial wastes has caused greatest concern, especially for the possible effects on ground-water quality. Necessary precautions have been established in the requirements of the Illinois Environmental Protection Agency (IEPA) which has authority to control, prevent, and abate pollution of streams, lakes, ponds, and other surface and underground waters in the State. Before any construction can begin on storage in subsurface strata, a permit must be secured from the IEPA. Eight basic design policies have been adopted that have to be met before a construction permit will be issued.Sandstone, limestone, and dolomite are the basic lithologies most commonly considered as potential disposal reservoirs in Illinois. From well cores of such formations, essential laboratory studies are conducted defining the rate of fluid movement, porosity, and permeability of the rock and the pressure distribution within the aquifer.Plugging of the injection horizon is the most serious cause of damage to a fluid injection system and results from the forming of an impermeable deposit on the well bore or plugging in the formation itself. In either case the plugging may result from a number of listed causes.To date there have been four industrial waste disposal wells in Illinois. Variation in conditions is illustrated by these cases of disposal wells that have been authorized by the State.The first practical use of underground gas storage in Illinois was at Waterloo in 1950. Since then, the number of projects and their capacities have grown continuously. At the present time there are 24 underground gas storage projects. Gas injection pressures must be kept below the fracturing pressure of the caprock. In underground gas storage reservoirs in Illinois, injection pressures of approximately 0.55 psi per foot are often used.Secondary recovery by water flooding accounted for 73.4 percent of the total oil production in Illinois during 1968. In that year there were 880 active projects in Illinois with 13,107 water injection wells that injected 2581 million gallons of water.

Notes: Nonequilibrium pumping tests were performed at two widely separated sites consisting of one pumped and two observation wells each. The wells at both sites bottomed in the same stratigraphie formation; at one site a confined aquifer was tested, at the other the aquifer was unconfined. Data gathered from the tests were analyzed using the methods developed by Theis (1935), Jacob (1946), Chow (1952), and Hantush (1961). Eight separate determinations of transmissibility, permeability, and specific yield were made at each site. At the unconfined site, all eight determinations of permeability and transmissibility fell within nine percent of the mean of these calculated values. Specific yield predictions showed a wider variation, with individual computations differing by up to 55 percent from the mean at the confined site. No one method was found to yield consistently higher or lower values for the computed hydrologic characteristics; rather, the observation well used to make the analysis was found to have a more marked effect on the results obtained. Analysis of the well recovery curves confirmed the existence of local recharge near the test sites, explaining the apparent effect of the use of data from different observation wells on the analysis.

Notes: Ground water is an important source of water supply in Czechoslovakia, and its use is very carefully planned because the resources are unevenly distributed. The supply is limited because Czechoslovakia is situated on the European water divide between the North, Baltic, and Black Seas, and all waters flow out of the State. The paucity of ground-water resources, requiring assessment and classification of the utilizable ground water, has led to development of a State ground-water resources zoning plan. Increasing demand for ground water has resulted in extensive and responsible hydrogeological research, contributing to a good knowledge of the ground-water resources. Czechoslovak hydrogeology has been developed to a high level, even though it is a relatively young branch of science, and stands in some respects in the forefront of world hydrogeology, especially in prospecting, development and protection of mineral-water resources, hydrogeological mapping, and ground-water zoning.

Notes: Many subtle aspects of water levels in carbonate rocks need to be put in perspective even though hydrologists have recognized the fundamental value of characteristics of ground-water levels. The depth to the water table in carbonate rocks is controlled by local factors such as permeability and topography and by the regional factor of climate; both permeability and topography are dynamically developed according to the degree of preferential circulation of subsurface water and of solution of the rock, and the water table responds by lying deep beneath hilly permeable karstlands and shallow beneath flat and poorly permeable carbonate rocks. The uneven distribution of permeability and of topographic conditions is responsible for the intriguing karst phenomena of disappearing and reappearing surface streams. Great infiltration capacities of some karst regions result in large local fluctuations of the water table and in some cases to local reversals in direction of ground-water flow between wet and dry seasons. Water-level behavior in space and time is a primary consideration for interpreting the hydrology of carbonate terranes.

Notes: Theory indicates that the effect of a discharging well on a nearby stream is independent of the length of the reach. The theory was confirmed using a digital computer model of short and long reaches of a stream-aquifer system. Digital computations using short reaches of most stream-aquifer systems will give results comparable in accuracy to one of a long reach with considerably less effort and expense.

Notes: Acidic industrial wastes have been injected into deep wells in a limestone aquifer near Pensacola, Florida, since 1963. Prior geohydrologic studies in the area had indicated that the limestone aquifer contained nonpotable water and was overlain by an extensive clay confining layer.Two injection wells are presently being used to inject the waste at a rate of approximately 2,000 gallons per minute. The injection pressures are about 200 pounds per square inch. Over 3 billion gallons have been injected. Data from a current study indicate that the waste may extend outward about 1 mile from the injection wells, and pressure effects may extend outward more than 25 miles. Monitor wells show that pressure changes are following a predictable pattern. No wastes have been detected in a monitor well open to the Floridan aquifer immediately above the Bucatunna Clay Member of the Byram Formation and 100 feet from one of the injection wells.A monitor well open to the receiving formation was constructed about 1,300 feet south of the injection wells. Geochemical effects of the wastes were detected at this well about 10 months after injection began. In early 1968, the pH of the waste was lowered to about 3. Effects of this waste, which included a large increase in calcium, were detected at the monitor well about 5 months later.

Notes: A new method is presented for supplementing data from piezometers to monitor waste disposal sites. This method involves examination of a time sequence of resistivity measurements at fixed points in a disposal area.Spent sulfite liquor moving away from a seepage pit was traced by examining a grid of earth resistivity measurements made before and after dumping had taken place. The method appears to provide results which correlate with specific conductivity of water samples from piezometers provided the following conditions are met:〈list xml:id="l1" style="custom"〉1Highly conductive contaminant moving at shallow depth.2Water table close to surface.3Uniform soil and vegetative conditions.4Proper selection of electrode spacings.

Notes: Management of ground water in coastal aquifers is composed of major elements which should be properly evaluated. Emphasis should be made on evaluating these elements by means of basic research; otherwise, the management approaches and research would have no sound foundation. The major elements needed for a proper management are critically discussed and some current misconceptions are pointed out. Special attention is given to leakage and salt-water encroachment problems. The current means of alleviating salt-water effects are discussed and a new approach is presented.

Notes: There is a tendency during the verification stage of aquifer model building to manipulate stratigraphic boundaries. This procedure is acceptable insofar as the geohydrologist is sufficiently knowledgeable to sense the point at which the manipulations encroach upon the integrity of his model.Examples from the Maryland Coastal Plain are used to depict several types of stratigraphic boundaries. These include erosional truncation, overlap (or pinchout), disconformity, and facies change. Defining statements are given for each in order to clarify the stratigraphic implications of boundary modeling.

Notes: Petroleum contamination of ground water is a widespread problem that plagues many areas. Historical data collected in Maryland indicates that most counties in the State record cases of this contamination problem annually. Cases in the “hard-rock areas” west of the Fall Zone have the highest frequency of occurrence, in contrast to the Coastal Plain geologic province to the east. In both areas, the problems have been very localized. It is difficult to handle petroleum contamination cases, and the legal implications are very complex. A disturbing factor is that many petroleum fuels do not deteriorate in the ground-water system. Further, the identification of specific petroleum products in ground water is generally not possible with present techniques. An investigation of a particular complaint can often be split into a preliminary phase and a detailed site investigation phase. Once a source of contamination is located, it must be stopped or removed. Since it is virtually impossible to remove the contaminant from the ground water, legal and regulatory problems continue on for months or years after an original complaint.

Notes: A study of the character and movement of landfill leachate through unsaturated soil was begun in 1967 at the State College (Pennsylvania) Regional Sanitary Landfill which has operated since 1962 employing the trench method of waste disposal. The landfill occupies a gently sloping underdrained valley with a water table more than 200 feet below land surface. Precipitation averages about 37 inches as rain per year. Residual sandy-clay to sandy-loam soils range from a few feet to greater than 70 feet in thickness on a sandy dolomite bedrock. Soil moisture samples were extracted at different depths from beneath two of the refuse cells using suction lysimeters. Water samples were also bailed from these cells and pumped from a water table well beneath the landfill. Monthly or less frequent analyses performed on water samples included Eh, pH, temperature, specific conductance, BOD, Cl, SO4, total alkalinity, NH3, NO2, NO3, PO4, Ca, Mg, Na, K, and total Fe. Soil samples from beneath the refuse were subjected to particle size and x-ray analysis, and chemical analysis of soil pH, soluble salt content, exchangeable Ca, Mg, Na, and K, cation exchange capacity, and extractable P content.The study showed that the quality and quantity of leachate beneath a landfill varies considerably with the topographic setting of landfill trenches or cells. Leachates 2 feet under an upslope cell which received only direct precipitation, had the following maximum values 3-13 months after refuse burial: specific conductance 8445 μmhos, Cl 1890 mg/1, BOD 3300 mg/1, NH3-N 540 mg/1, and total Fe 225 mg/1. Upon reaching a depth of 14.5 feet after about 21/2 years or more, maximum values of these species in the leachate had been reduced by 83%, 80%, 〉99%, 〉99%, and 98% respectively. In contrast, more water, including precontaminated surface and subsurface runoff from adjacent upslope cells; infiltrated a downslope cell, saturating the refuse. Even after moving downward in the soil to a depth of 36 feet in 7 years, the leachate beneath this cell had a conductance of 6600 μmhos, 600 mg/1 Cl, over 9000 mg/1 BOD, 40 mg/l NH3-N, and 100 mg/1 total Fe. A practically continuous depletion of inorganic species in the refuse as indicated by the quality of leachate from both cells has occurred with time. However, concentrations of BOD and redox sensitive species such as Fe and NH3 in the leachate have fluctuated in response to changes in the moisture content and temperature of the refuse.Leachate beneath instrumented cells is moving downward in the subsoil at the rate of 6-11 ft/yr. Observed mechanisms of leachate renovation during this downward percolation, along with supporting evidence for each listed parenthetically, include: dilution and dispersion (decrease in Cl with depth); oxidation (Eh and pH measurements, decrease in BOD and Fe with depth); chemical precipitation (decrease in soil extractable P after leachate percolation); cation exchange (increase in percent base saturation of clays affected by leachate, and depletion of NH3 under reducing conditions—bacterial growth may also retard or remove NH3); and anion exchange (decrease in SO4 with depth). Removal of bacteria, suspended ferric oxyhydroxides and other particulates by soil filtration undoubtedly also occurs. Although renovation takes place, it is incapable of preventing highly contaminated leachate from moving to depths of 50 feet or more in soils beneath downslope cells. Ground-water contamination has occurred, probably by leachate channelled down fractures in locally shallow bedrock, or by leachate contaminated runoff from heavy storms which has entered sinkholes or infiltrated along the valley bottom. The study shows that improper design of landfills emplaced above the water table in relatively permeable soils and bedrock such as are found in many carbonate-rock terranes, can result in serious ground-water pollution.

Notes: A leak in a product gasoline pipeline near the City of Los Angeles has caused contamination of a valuable groundwater supply. Since 1968, it is estimated that 250,000 gallons of gasoline have seeped into the underground reservoir, limiting the value of a well field adjacent to the contaminated area.Remedial measures include extensive analytical studies of the two-fluid flow system as well as an all out effort in the field to try and clean up the gasoline and restore the aquifer to service. The field methods involve an elaborate system of “skimming” wells designed to produce a high gasoline/water ratio and on-site treatment facilities at many locations throughout the area. To date, 50,000 gallons of free gasoline have been removed from the aquifer in this manner.

Notes: Water-level declines in the principal artesian aquifer have created a head imbalance between the aquifer and an underlying brackish-water zone containing up to 4,550 mg/1 chloride. The brackish-water zone leaks brackish water into the aquifer through several breaks in a confining unit.A relief well tapping the brackish-water zone was drilled near a suspected break and pumped at about 3,000 gpm to lower the potential in the zone and bring it into hydrostatic equilibrium with the aquifer. The pumping apparently succeeded in decreasing the rate of brackish-water leakage into the aquifer. Successive samples of water from a well tapping the aquifer and downgradient from the relief well showed a decrease in the chloride content. Several more relief wells may be necessary to ultimately control chloride contamination of the aquifer.