ALBERT

Notes: New sanitary landfills are being opened each day to accommodate the rising volume of solid wastes. Selection of proper sites is a very major part of the disposal problem, particularly as they might affect the surrounding surface and ground water.Leachate production is inevitable in the humid East and throughout most of the country. Several alternatives are suggested that would result in the assimilation of migrating leachate into, the environment at tolerable limits or for its renovation prior to final discharge: Alternative 1—knowledge of existing hydrogeologic conditions which would favorably control the rate and direction of leachate migration; Alternative 2—engineering the landfill by construction of low-cost facilities to collect and treat leachate; and Alternative 3—construction of limited collection facilities to supplement natural conditions.It is suggested that more emphasis be given to hydrogeologic factors in the selection of refuse disposal sites to insure protection of surrounding surface and ground water. It is time to approach the waste disposal problem on a more sophisticated level by requiring test drilling, monitoring, and by giving consideration to the engineering of, landfills so that man's health and' environment are not jeopardized.

Notes: A simple and rapid method of determining casing length and permeable zones in wells tapping bedrock can be useful to well drillers and hydrologists. A device consisting of a galvanometer, a reel of insulated wire, and a copper electrode locates the casing depth, changes of lithology, and permeable zones. The small-diameter electrode permits measurement through well-seal access ports avoiding the expensive and time-consuming procedure of removing the seal and drop pipes to measure casing depth with a magnet. The measured electromotive force changes rapidly when the electrode passes the end of casing. Thus, the depth of casing is easily determined from the length of wire payed out. Changes in electromotive force measured within the uncased part of a well frequently indicate permeable zones, thereby aiding in choice of the most efficient drop-pipe length, and also yielding useful information for hydrogeologic studies.

Notes: The best features of analog and digital computers were combined to make a management model of a stream-aquifer system. The analog model provides a means for synthesizing, verifying, and summarizing aquifer properties; the digital model permits rapid calculation of the effects of water-management practices. Given specific management alternatives, a digital program can be written that will optimize operation plans of stream-aquifer systems. The techniques are demonstrated by application to a study of the Arkansas River valley in southeastern Colorado.

Notes: Underground detonations may produce observable effects in surrounding aquifers and wells. The nature and the duration of the effect at any observation point seem to depend on several factors such as the amount of energy released by the detonation, the geologic environment, the position of the buried explosive device in relation to the saturated zone, aquifer characteristics, and the distance from point of detonation. Precise measurement of these effects in wells presented numerous technical problems and resulted in the development of specialized techniques. Initially, these effects were observed by measuring the fluctuation of the free water surface in wells. The current technique employs high-resolution pressure transducers deep in the water column. Pneumatic packers may be used to restrict the movement of water into the well. Data are recorded on high-speed oscillographs.

Notes: Present ground-water use in Ohio, approximately 650mgd (million gallons per day) amounts to about 5 percent of the water that enters the ground-water reservoirs. The largest ground-water supplies are developed where natural concentrations of water occur, chiefly in the watercourse aquifers, which consist of sand and gravel of glacial origin (outwash) in the valleys of the major streams. Other important aquifers are glacial outwash in upland areas and in the buried Teays Valley system, the limestone and dolomite aquifers in western Ohio, and sandstone and shale aquifers in the eastern half of the State.Future outlook is that more of the increasing water demand will be met from ground-water sources. Ground-water supplies will be developed at many new sites, and aquifers in areas already heavily pumped will be made to yield more water by the drilling of additional wells and recharging the aquifers artificially. Large quantities of ground water in storage, virtually unexploited, could be used for temporary low-flow augmentation of streams. Management of ground-water resources will be needed to help solve supply and distribution problems, and to resolve conflicts between users. Among future problems will be those arising from underground disposal of wastes, a practice which is expected to grow substantially from enforcement of water-quality standards for streams, set under the Federal Water Quality Act of 1965.

Notes: Pumping test data from a single well were used to estimate aquifer volume affecting drawdown. After four days of pumping from a 240 feet thick welded tuff aquifer in southern Nevada, the volume of the wedge-shaped mass tested was estimated to be about 15.6 billion cubic feet (440 million cubic meters). The field coefficient of permeability of the aquifer is 275 gallons per day per square foot.

Notes: In Southern California's San Bernardino Valley a unique experiment is being performed by a local water district, the State government, and a private industry. Both the experiment and the organizational arrangements for getting the job done are the subject of this paper. The experiment is the application of systems analysis technology to water resource management. The organization is formed by a combination of contracts and cooperative agreement between private and government agencies. The result is a favorable environment for the development of effective water resource management strategies.The San Bernardino Valley is similar Co many areas in the world where water resource management reduces to the allocation of locally available ground water and potential imported water resources. This paper outlines in detail the analysis tools and long-range planning needs of effective ground-water management strategies.

Notes: Coal mining in Appalachia has degraded both the surface and ground water. During mining, ground water is drained from the rocks and the pyrite associated with the coal beds is exposed to air. Oxidation of the pyrite produces high iron ana sulfate concentration and a low pH in the water. Some of this polluted water flows directly into nearby streams and some moves into the ground-water system. When the latter occurs, the iron concentration can increase up to several hundred mg/1 and the sulfates to over one thousand mg/1. Unfortunately, in most cases the cessation of mining does not stop the ground-water pollution, and it can take many decades before the ground water again becomes usable.A detailed study of the effects of coal mining on ground water was conducted in the Toms Run drainage basin in northwestern Pennsylvania where coal mining and oil and gas well drilling have occurred for almost 100 years. The rocks of Mississippian and Pennsylvanian Age produce a multiaquifer system–three major aquifers separated by siltstone and shale beds (aquitatdes). The oil and gas wells act as a conduit system permitting acid mine drainage to move downward from the strip mines to underlying aquifers. It then moves laterally down dip and discharges as springs. The acid mine drainage adversely affects the ground-water quality by increasing the iron and sulfate content of the water especially in the vicinity of the strip mines.

Notes: The measure of earth resistivity is a possible means of detecting and outlining zones of ground-water contamination where a resistivity contrast exists between contaminated and unconcaminated ground water.As a preliminary evaluation of the use of electrical resistivity for defining zones of contaminated ground water, five sites on Long Island and three sites in western Texas were examined. The surveys at three of the Long Island sites and at one of the western Texas sites were at least partially successful in their objectives. The lack of success at the other sites is attributed to the particular physical conditions that existed.Further effort toward developing electrical resistivity as a method for evaluating variations in ground-water quality is encouraged.

Notes: Water-supply problems in Spain have become acute during the past decade owing to expansion of industry, construction of modern houses and apartments, and development of a tourist industry. A training program in ground-water hydrology and geology was established three years ago in Barcelona to help supply personnel who would be able to cope with these problems. Training is also given to foreign nationals, a total of nine countries having been represented to date. Part of the success of the school rests on the fact that a large variety of ground-water problems exist in the vicinity of Barcelona. Students obtain a firsthand knowledge of sea-water intrusion, aquifer-testing techniques, agricultural and municipal degradation of water quality, and drilling and exploration techniques within a wide variety of rock types.

Notes: A well-designed and calibrated orifice meter is an accurate and inexpensive measuring device for flow. Endline orifices can be calibrated at work sites by solving an equation that interrelates easily measured dimensions of the orifice and outflow.

Notes: Expanding water requirements during recent years have intensified development of the productive sedimentary aquifers of the North Carolina Coastal Plain. The effects of this development emphasize the local and regional limitations of the aquifer system and the need for an effective management program.Withdrawal of about 60 million gallons per day from the Castle Hayne limestone, the most productive unit of the principal artesian aquifer of the area, began in July 1965 at a phosphate mine adjacent to the Pamlico River in Beaufort County. Within a few months, the artesian head was lowered below sea level in an area of about 800 square miles, and to more than 100 feet below sea level in the immediate vicinity of pumping. Under these conditions the aquifer became vulnerable to encroachment of saline water from (1) areas of natural occurrence of brackish water in the limestone member of the aquifer; (2) leakage of brackish surface water through the confining beds; and (3) vertical movement of brackish water from the underlying sand member of the aquifer.The dramatic and “overnight” effects of the large withdrawals at the mine site and the threat of damage to the aquifer created sufficient public concern so that legislation was passed by the 1967 General Assembly, giving the Board of Water and Air Resources authority to regulate ground-water withdrawals as needed to protect the aquifers of the State. An adequate management program can be accomplished that will not only protect the aquifer but will improve the development potential. The development of such a management program requires a thorough knowledge of the hydrology of the aquifer system, the objective of studies in progress. The implementation of the program will require the support of an informed public.

Notes: The planned development of an individual water supply from a group of wells must take into consideration several controllable and uncontrollable factors. The uncontrollable factors may include aquifer coefficients of transmissibility and storage, aquifer boundaries, static water level, aquifer depth, recharge capabilities, and competing users. The controllable factors often include the acreage allocated to ground-water development, well locations, and pumping rates. Well-field design is oriented mainly toward proper selection of the controllable factors.Water requirements, the cost of water and the life of the well field are related to limitations of acreage, draw-down of water level, and investment in pumping and transmission facilities. All of these factors, in turn, are influenced by the location of individual wells with respect to one another.Well-field design calculations involve the combined interference of water level drawdown among the various wells in the field. Repeated computational trials for various numbers of wells and well spacings may be required. Calculations using conventional methods are, in most cases, rather time-consuming.The final design decision can be approached quickly if it is assumed that the wells have regular spacing. Through the use of a simple formula and table developed in this paper, a given well-field problem can be calculated in a few minutes with a slide rule. When well spacing deviates appreciably from the regular spacing assumed, the final design calculations should be made with computer techniques.

Notes: This article contains a summary of a few disease out-breaks caused by ground-water contamination, and the difficulties in designing and monitoring for effective quality control. There is a discussion of problems associated with large basin recharge with treated sewage. For instance, do we have adequate microbial indicators? Or will the nitrate concentration build up if there is a semiclosed circuit involved? Chlorination of well water withdrawn for domestic use is advocated as good insurance for microbial control.

Notes: A new design method for deep well dewatering systems is given. The method analyses three dimensional flow to the multiwell systems by considering the two end points to the initial fast phase of water table fall. The method is applied to a dewatering case history and proves to be successful.

Notes: A new method of determining aquifer storage coefficients has been developed for use in operations involving ground-water recharge through wells. This work evolved from a research project dealing with the fate of DDT and nitrate in the Ogallala Aquifer in the High Plains of Texas.A tritium tracer was used to determine the detention time of the recharge water passing through a saturated volume of the aquifer. Tracer behavior was formulated ‘mathematically and verified by model simulation. The formulations provide a graphical solution for the detention time from which the storage coefficient may be calculated.The method will have immediate value in establishing storage coefficients of aquifers, such as the Ogallala, where plans for importation and distribution of supplemental water involve utilization of underground storage. Regarding water-table conditions, this method promises to produce more reliable storage values than have been obtained from pumping tests.

Notes: An analysis is presented for the nonsteady state problem of a well, pumping a constant discharge, and located at the center of a circular aquifer surrounded by a radial discontinuity. On either side of the discontinuity, the transmissibility and the storage coefficient are constant but may have different values from those on the other side of the discontinuity. The solution is obtained by using an approximate inversion formula for Laplace transforms. This method leads to a relatively simple set of equations which commonly requires only short computer time for solution.

Notes: The growing number of ground-water research projects that are based primarily on potential distribution data has stimulated the development of several new types of potential measuring, instruments. The primary requirements for these instruments are longevity, precision, sensitivity, and short timelag. Ease of installation, minimum maintenance, low capital investment, and provision of a continuous record are equally desirable. Generally, available instruments will satisfy two or three, but not all of these requirements.The need for a piezometer possessing all these characteristics was encountered during a flow-system study beneath an irrigated field. A piezometer subsequently was designed which combines the sensitivity of a Kecke electrical water-level sensing device with the continuous record provided by a Stevens Type F, graphic recorder. Replacement of the standard Keck sensing “Bob” with a probe specifically designed for small diameter pipes (5/16-inch I.D.),* provides instrumentation with a short timelag. The absence of a diaphragm and strain gauges enhances longevity. The device is inexpensive, simple and easily installed. Samples of well water for chemical analysis may also be obtained from the piezometers.

Notes: In a steady-state condition the lateral flow rate through the unsaturated zone of an unconfined aquifer increases with a decreasing rate as the depth of the unsaturated zone increases while hydraulic gradient is kept constant. This flow rate reaches a maximum as the depth of the zone is increased. This maximum flow rate is computed by various methods such as an aquifer model, graphical integration of the characteristic hydraulic conductivity curve and a flow net diagram. Based on these calculations a simple method is outlined for estimation of steady-state flow rate through the unsaturated zone of an unconfined aquifer. It is also concluded that in shallow unconfined aquifers the contribution of the flow through the unsaturated zone to the total lateral flow can be significant.

Notes: The need for a Federal role in the water resources development of the United States was recognized early in its history. The 20th century has seen a dramatic acceleration of activity in the water resources development field, with a concomitant increase in Federal participation. By 1960 the need for coordinating the many Federal programs in water planning and related resources development became apparent. A Senate Select Committee on National Water Resources was formed. The Committee's report was the basis for the Water Resources Research Act of 1964 and the Water Resources Planning Act of 1965. The objective of the Water Resources Planning Act is to provide for optimum development of water resources through the Water Resources Council and several River Basin Commissions, and by providing financial assistance to the States in order to increase State participation in water resources planning. A Council report on the Ohio River Basin will be published soon; this should be followed by the Missouri Rivet Basin report before 1970. The completion of reports for all major river basins has been scheduled for the mid 1970's. These framework studies include population, economic development, and water supply and water use data projected as far as the year 2020. The Water Resources Council also prepares a biennial assessment of the adequacy of supplies of water necessary to meet the requirements in each water resource region in the United States. For this purpose a river basin model is being prepared to determine probabilities of deficiencies and quality requirements in 300 basins, and economic concepts for determination of optimum water use alternatives are being incorporated in the model. Another assignment to the Council under Title I of the Water Resources Planning Act is the preparation of guidelines for all Federal participants in comprehensive regional water planning, and for the formulation and evaluation of Federal water resources projects of all types. The Council also is working on specific proposals for improved floodplain management. Title II of the Act authorizes the President to establish river basin commissions at the request of one or more States and with concurrence by the Council. Title III provides a basis for increased participation by the States in water planning by granting of matching funds. All but two States are now taking part in the State Grant program.

Notes: A preliminary geohydrologic survey was carried out in the Lower Shire Vailey, Malawi, Africa in the summer of 1967. The valley is part of: he East African Rift System. In order to develop more adequate knowledge of subsurface conditions, a reconnaissance gravity survey was performed. The survey showed that potential aquifer material over much of the valley was too chin to support high yield irrigation wells. In addition, when combined with hydrochemical data the survey disclosed a high probability of water contamination by brines circulating upward along fault systems.

Notes: A review of the literature and a study of a number of field tests shows that the presently used analysis and interpretation of step-drawdown tests can be misleading. The efficiency of a well is defined. The usefulness of the step-drawdown test is outlined and a hypothesis for reduction in specific capacity is offered.

Notes: Use of this material will assist in the determination of cost of pumping water, given the quantity of flow required, the total pumping head, the wire-to-water efficiency, and the unit cost of power.A table of conversions is presented to aid in reducing theoretical equations to simplified equations, and a figure is provided for graphical solutions of the equations.

Notes: The very diverse types of ground-water behavior in carbonate terrains can be classified by relating the flow type to a particular hydrogeologie environment each exhibiting a characteristic cave morphology. The ground water may move by diffuse flow, by retarded flow, or by free flow. Diffuse flow occurs in less soluble rocks such as extremely shaley limestones or crystalline dolomites. Integrated conduits are rare. Caves tend to be small, irregular, and often little more chan solutionally widened joints. Retarded flows occur in artesian environments and in situations where unfavorable stratigraphy forces ground water to be confined to relatively thin beds. Network cave patterns are characteristic since hydrodynamic forces are damped by the external controls. Solution occurs along many available joints. Free flowing aquifers are those in which solution has developed a subsurface drainage system logically regarded as an underground extension of surface streams. These streams may have fully developed surface tributaries as well as recharge from sinkholes and general infiltration. Characteristic cave patterns are those of integrated conduit systems which are often truncated into linear, angulate, and branchwork caves. Free Flow aquifers may be further sub-divided into Open aquifers lying beneath karst plains and Capped aquifers in which significant parts of the drainage net lie beneath an insoluble cap rock. Other geologic factors such as structure, detailed lithology, relief, and locations of major streams, control the details of cave morphology and orientation of the drainage network.

Notes: Four principal trends in ground water are apparent:(1) Increasing use of ground water for domestic supplies. Geohydrologists must learn to quantitatively evaluate the supply under conditions of maximum development, not merely determine the availability of a supply that does not strain the aquifer. (2) Aquifers will be looked to increasingly as possible storage media for surplus flood water, in place of dams and reservoirs. The key here is economics – optimum utilization of resources. The job of the geohydrologist is to do enough research and experimentation to determine when, where, and how ground-water reservoirs can be recharged artificially at a reasonable cost. (3) Saline aquifers will be looked at as sources of water supply. The cost curves of developing new supplies of fresh water are ascending while the cost curves for desalinization are declining, and inevitably they will cross in one area after another. There is a paucity of information on saline ground-water aquifers; hence, the utmost skill must be used in evaluating the resource. (4) With efforts to prevent stream pollution, aquifers will be looked to increasingly as possible storage media for industrial and domestic waste effluents. Control is urgently needed so the effects of waste injection can be predicted, the technology for confining those effects as intended can be developed, and a basis can be provided for a rational decision as to whether waste injection or an alternative use of the chosen aquifer is best for the economy in the long run. However, there is little legal basis for control, and the cost of such control may make the practice unfeasible in many situations.A systems-analysis approach is needed to develop a working model of a given hydrologie and socio-economic problem from which quantitative answers can be given to water planners.

Notes: Pollution of ground water to the point of crisis in Missouri can be eliminated by an awareness of geology, by planning, by adequate funding, and by authority to follow planning. Ground-water pollution hazards are widespread in southern Missouri where permeable soils and cavernous bedrock exist. Pollution in northern Missouri is more localized. All of the pollution in Missouri that we have attributed to geologic features could have been avoided if the polluters–municipal and private–had obtained adequate geologic information, used common sense, and supported waste disposal plans with adequate financing.

Notes: The build-up of American military force in Vietnam has necessitated a massive well-drilling program.Engineering investigations were carried on concurrently with drilling to evaluate various related water resources.Water quality problems including salt-water encroachment existed in many areas.Between July 1966 and September 1967. 48 test holes and 233 successful 8 inch wells were drilled. The average producing well yielded 95 gpm.

Notes: The use of this material will give an estimate of the well and pump costs for projects requiring a given capacity. This is intended only as an instrument for establishing orders of magnitude as a basis for comparisons, and of course does not substitute for detailed engineering studies.Well cost data were analyzed for three categories according to the aquifer tapped: sand and gravel, shallow bedrock, and deep sandstone. In the sand and gravel category, tubular and gravel packed wells finished in the glacial materials above bedrock were considered separately.

Notes: This paper deals successively with some general concepts of scientific communication, with the characteristics of four well-known hydrology journals and with ways in which messages are obtained. The most important conclusion is a rationale for restrained publication.

Notes: Sea-water intrusion into ground-water reservoirs occurs when permeable formations outcrop into a body of sea water and when there is a landward gradient. Intrusion can be controlled by reducing pumping, by increasing supply, or by forming some type of barrier. A pressure barrier has been operated in Los Angeles County, California. Special facilities are needed. Costs of operation are high.The intrusion of sea water into ground-water reservoirs can greatly impair the water-supply systems of local areas adjacent to coastlines and tidal estuaries. Such intrusion is always the result of some activity of man either in trying to improve his environment or in his use of natural resources. Following is a discussion of how intrusion occurs, some ways of controlling intrusion, the results of one project in southern California where intrusion is being controlled, and some examples of related costs.

Notes: Approximately two-thirds of the present population live in the urban environment; by the year 2000, it is anticipated that five-sixths of the population will be urban. The trend of metropolitan growth is not the continued growth of major cities, but rather the expansion in population and size of the smaller suburban communities. The urbanization of the country is reflected in the emphasis on comprehensive water resources development – area-wide and basin-wide planning and management. In some areas of intense urban development the problems of water quality control, recreational use of water, and water for cooling and waste transport have become more significant than problems of adequate supplies for withdrawal. A major share of future water resource investigations will necessarily be directed to the urban environment, where geologic and hydrologic data is needed in urban planning.The general pattern associated with community development–the initial use of ground-water resources by individual systems, to the use of a community well and distribution system, and finally the use of surface-water sources far removed from the urban center–has contributed to the development of the “commodity concept’ of water use. By this attitude the water resource is viewed only in terms of its adequacy as a water supply; waste discharge and recreation uses are being ignored or considered a‘ downstream” problem. This concept is particularly inappropriate when applied in the multicommunity complexes of the metropolitan areas where there is little in the way of a “downstream.” Water problems must be dealt with at the metropolitan level rather than at the individual community level; and not by a proliferation of smaller units of government and public agencies that often overlap and duplicate effort. The nature of the metropolitan complex requires that we think in terms of closed systems involving reclamation and reuse rather than in terms of the open system of withdrawal, use and discharge.

Notes: Most State ground-water programs can be grouped under three headings: basic data collection, answering requests, and research and report writing. In Ohio the staff consists of four geologists, two hydrologists, and one field inspector. Most time is spent collecting basic data and answering requests for assistance.(1) Basic data collection: It is the responsibility of one hydrologist to maintain and coordinate the 150 State observation wells. The field inspector is responsible for seeing that well logs are submitted by well drillers in accordance with State law. The inspector is a geologist who works closely with the drillers; he is also active in the Ohio Well -Drillers Association, and prepares a quarterly newsletter. A highly organized well-log file system is maintained, and there is a field location program whereby well locations are plotted on large-scale maps. A ground-water quality sampling program is in operation. A network of 20 existing production wells in strategic areas was established for observing seasonal and annual changes in ground-water quality. A monthly summary of water-supply conditions across the Scace is published.(2) Answering requests: Of the 2,000 requests answered each year, approximately 80 percent involve domestic wells. The remaining inquiries are from industries, municipalities, schools, developers, State agencies, and various commercial or recreational interests. In answering requests a report summarizing hydrogeology and ground-water availability is prepared. For large ground-water developments that are not State-financed the services of a consultant are recommended.(3) Research: Much research in the public interest is concerned with problems and potential problems in ground-water pollution.

Notes: A simplification of the two most commonly used methods of network planning and scheduling is ideally suited to the planning and evaluation of both water resources studies and construction projects. The project planning diagrams illustrate the system for scheduling of project activities and the relation of each activity to the others.

Notes: The Deep Tunnel System planned by the Metropolitan Sanitary District of Greater Chicago will provide flood and pollution control for the combined sewer areas of the Chicago region. Elements of the Deep Tunnel System that are of main concern to the ground-water resources of the area are the conveyance tunnels and the mined storage reservoir which will convey and store polluted storm-water overflows. The Silurian and the Cambrian-Ordovician aquifers, in units of which these elements will be located, will be protected from any deleterious effects of the System by ensuring that a positive hydraulic head, causing an inward flow, is continuously maintained around the tunnels and the mined reservoir. In the Cambrian-Ordovician aquifer, this necessitates1 that ground-water levels are maintained by artificial recharge. Extensive ground-water studies were conducted to (1) demonstrate the feasibility of aquifer protection by recharge, (2) determine the needed amounts of recharge water, and (3) estimate the seepage of ground water into the tunnels and mined res.ervoir. The studies included field investigations, analog computer analyses and office evaluation of the collected data and analog results. The results indicate that (1) the proposed aquifer protection is feasible, (2) the recharge requirements will vary from 1.4 mgd in 1976 to 6.0 mgd in 2010, (3) seepage into the tunnels will be small, in amounts that can be easily controlled.

Notes: The project developed between the U. S. Army Corps of Engineers, Office of Appalachian studies and the U. S. Geological Survey for a study of the ground-water resources in Appalachia had two principal objectives. The first objective was to describe in general terms the ground-water resources of the Region as a whole and the second objective was to describe in greater detail the ground-water resources at about 20 selected sites. This paper deals with the methods used to describe the Region as a whole, wich a special emphasis on availability and cost of developing ground water, as was requested by the Office of Appalachian Studies.

Notes: The standard water-level indicator can be easily and inexpensively modified so that it also measures casing lengths. The simple modification permits electrical current from one wire of the two-wire probe to be routed through the metal casing. The semiquantitative method works well with most metal casings, including nonmagnetic ones, and can be used to detect most casing reductions. The method is limited in that it works only below the water level in the well, and in that it cannot easily detect casing reductions when the conductance between the upper and lower casings is low.

Notes: An aquifer test and analyses of water samples, showed that the anomalous water quality of a municipal well was caused by leakage from a nearby abandoned well tapping another aquifer.

Notes: Electric-analog or digital-computer models are used to compute the effect of ground-water withdrawal or recharge on streamflow. The results can be generalized on a map showing lines of equal elapsed time. The lines indicate the time of recharging or discharging that is needed to affect the streamflow by a given fraction of the amount pumped or injected. The generalization is based on the similarity in shape of the relations between pumping time and stream depletion for (1) semi-infinite homogeneous aquifers drained by a straight, fully penetrating stream, and (2) complex heterogeneous aquifers. Response curves from a model reflect the combined effect of stream sinuosity, irregular impermeable boundaries, areal variation in aquifer properties, and imperfect hydraulic connection between the stream and aquifer. The elapsed-cime lines are identified by sdf (stream depletion factor) values. These values can be calculated from observations made on an electric-analog model and then may be used in a digital-computer program for determining the effects of ground-water pumping or recharge on streamflow.

Notes: Hydrologic systems in arid lands normally include a recharge area in mountains and a discharge area in lowlands often with an intermediate area of lateral flow between recharge and discharge areas. This system is often modified by local geologic, climatic, and physiographic factors. Most water-supply, contamination and disposal problems arise from a combination of features superimposed on this system by concentration of population and agricultural activity in the discharge areas. Also most of our data on the system comes from the lowlands and little data is available from the recharge areas.In the Great Basin two general categories of ground-water flow systems are recognized: (1) local flow systems where drainage areas are usually small, flow paths are relatively short, interbasin flow is uncommon, springs have large fluctuations in discharge, water temperature is low, and concentration of Na, K, Cl, and SO4 is low, and (2) regional flow systems, where drainage areas are large, flow paths long, interbasin flow common, springs have large discharge, and the water is characteristically of higher temperature and contains higher concentrations of K, Na, Cl, and SO4. Hydrologic approaches used, in addition to conventional methods, include hydrologic budget, water-potential, and water-chemistry studies. Although detailed delineation of most flow systems in Nevada has not been accomplished, integration of hydrologic, geologic, and chemical methods allow approximate portrayal of many systems, both local and regional.Adequate methods upon which to base planning for optimum development of water resources in desert basins are now available. A conceptual model of optimal ground-water reservoir development illustrates how to determine optimum use of storage and perennial yield provided the use to which the water is to be put and the time of withdrawal are known.

Notes: In 1965, a ground-water recharge facility was constructed and placed in operation to forestall an impending water shortage at Minot, North Dakota. The facility is unique in that the rate of recharge to a buried sand and gravel aquifer is augmented by perforating an overlying bed of clay using hydraulic connectors (gravel-filled bored holes) in conjunction with an open-pit excavation. The connectors were drilled by typical well-boring techniques and the open pit was excavated by common construction methods. The recharge technique made it possible to add about million gallons per day of water to underground storage with a total capital investment of about $200,000. The alternative originally proposed was a 50-mile long pipeline to Garrison Reservoir, at a 1959 estimated cost of $12,000,000. The recharge technique employed at Minot should have wide application in the ground-water industry in areas where natural recharge to permeable deposits is impeded by overlying beds of low permeability.

Notes: A totally new concept, called the Deep Tunnel Plan for Flood and Pollution Control, is being implemented by the Metropolitan Sanitary District of Chicago. The plan envisions temporary storage of combined sewer overflows in a system of tunnels excavated in solid rock, deep under the City. After the end of a storm, the stored water would be pumped to the surface where it would be treated to remove pollution before being discharged into the waterways.Early planning studies indicate that the most favorable location for the tunnels is the Galena-Platteville Dolomite which is the uppermost member of the Cambrian-Ordovician aquifer. The protection of this highly-developed aquifer from any possible contamination is therefore mandatory for the feasibility of the Deep Tunnel Plan.Preliminary investigations using an electric analog model, constructed on the basis of available data, indicate that aquifer protection can be provided by a system of recharge wells which would maintain flow into the tunnels at all times. Further detailed studies are in progress to verify and refine those preliminary conclusions. These studies include (a) detailed exploratory drilling; (b) controlled aquifer tests in selected zones; (c) pumping tests for specific capacity in the zone to be tunneled; (d) recharge injection tests; and (e) analog model analysis for future effects of the tunnels and recharge operations.

Notes: The interdisciplinary graduate program in hydrogeology at the University of Idaho is described. The curriculum is structured to permit the design of individual study programs which are in keeping with multiple use concepts. Flexibility sufficient to permit courses to be taken in several fields which support the students' major area of research is provided. This flexibility is maximized by the offering of two degree options. Discussion of a number of the research projects at the University illustrates several of the types of problems now being studied.

Notes: The University of Connecticut well field is located in a sand and gravel ice-contact stratified drift aquifer which fills the Fenton River valley to a depth of about 60 feet. The water that supplies these wells consists of captured ground-water underflow which would normally discharge into the Fenton River, and water induced directly into the aquifer from river flow by pumping. Measurements of streamflow made at three weirs installed in the Fenton River adjacent to two of these pumped wells show the influence of wells on streamflow. Approximately 34 percent of the water pumped from the wells was stolen from the river via induced streambed infiltration, although this figure varies in accordance with pumping. Water-level measurements in 30 observation wells installed in the aquifer around the pumped wells show that the cones of depression spread underneath the river, following coarse-grained partially buried eskers. The fact that the water table is detached from the river and is below the streambed near the pumped wells is explained by the low vertical permeability of the streambed in contrast to the horizontal permeability of the rest of the aquifer. The streambed is unable to recharge the aquifer with as much water as the aquifer can carry away. Time-drawdown pumping test plots show no effect of the river.

Notes: A resistance network analogue is used to study the early stages of a pumping test in an unconfined aquifer. The results are compared with an alternative analysis due to Boulton (1965) and a good agreement is obtained.Unlike the theoretical analysis the analogue technique is versatile and can easily be used to study pumping tests with nonidealized boundary conditions, e.g., partially penetrating wells can be simulated. Thus the analogue method of analysis could prove to be a more realistic method for studying pumping tests than standard analytical techniques.

Notes: Coarse granular deposits in preglacial river valleys are an important source of ground water on the Canadian prairies. Such an aquifer can commonly be modeled by an infinite-strip leaky-artesian aquifer. Test results can be analyzed, future drawdowns predicted, and safe yields estimated by applying the standard leaky-artesian formula in conjunction with image-well theory, making due allowance for well-loss factors.This paper develops basic formulas required for safe yield estimation for an array of n wells located on the axis of an infinite-strip leaky-artesian aquifer. In general, determination of safe yield for each well depends on the solution of n simultaneous linear or nonlinear equations. For certain symmetrical arrays, however, the number of equations to be solved is approximately halved. A linear equation will apply for any well if flow adjacent to the well bore always obeys the Darcy law for all pumping rates of interest. If all n equations are linear, they may be solved by the methods of matrix algebra; if not, a trial-and-error solution must be adopted.The method is illustrated by an application to a 6-mile stretch of a buried-valley aquifer near Edson, Alberta. The numerical coefficients in the system of equations are first derived and the equations then solved to obtain estimated 20-year safe yields for well arrays containing up to 38 equally spaced wells.

Notes: In 1966 more than 50 billion gallons of water was pumped daily from an estimated 10 to 15 million water wells in the United States. This was more than one-sixth of the national withdrawal of water. On the basis of past rates of increase, a much greater future use of ground water is suggested. Our annual investment in water wells is one-half to three-quarter billion dollars, not including pumps and plumbing. In 1964 approximately 436,000 new wells were drilled; however, less than 1 percent of these wells were logged by any geophysical means. The application of _ge_o.phy.sical well logging to ground-water hydrology is comparable to its use in petroleum exploration in the 1930's; however, we can take advantage of equipment and interpretation techniques developed in the oil industry that are available now for use in ground-water investigations.Although most petroleum well logging techniques may be utilized in hydrology; modifications in equipment and interpretation are necessary because of basic economic and environmental differences between petroleum and ground-water evaluation. If logging is to be widely applied to ground-water exploration and evaluation, the expense of equipment and services must be reduced. Fortunately, this can be accomplished, because most water wells are not as deep as oil wells and the temperatures and pressures are lower.The Water Resources Division of the U. S. Geological Survey is conducting research on the application of borehole geophysics to ground-water hydrology. The following logging devices are utilized in the evaluation of ground-water environments: spontaneous potential, resistivity, gamma, gamma-gamma, neutron, radioactive tracer, flowmeter, caliper, fluid resistivity, gradient and differential temperature, and sonic velocity. Lightweight logging sondes and control modules are operated by one man, either on a vehicle-mounted 6,000-foot logger or on a suitcase-mounted 500-foot logger. An inexpensive magnetic tape system has been developed and is used routinely for log recording and playback.If commercial well logging service is to be widely used in ground-water exploration and development, water well contractors, and State and municipal agencies must be educated on the advantages of obtaining more information from each hole drilled. It will be necessary also to demonstrate how well logging can provide much of this information. In addition, the well logging industry must adapt their equipment and services to the requirements of ground-water hydrology. The need for additional logging capability in this field exists at the present time and is expected to increase. Hopefully industry will be able to fill the gap.

Notes: Heavy development in certain areas of the United States and the growing shortage of additional, readily available water supplies therein have forced planners and hydrologists to resort progressively to more elaborate water-supply systems. Among the most elaborate and most expensive systems proposed to date are the various plans for. transferring water toward the south from northward flowing Arctic rivers. A considerable portion of this water would be utilized for the expansion of already heavily urbanized areas.Meanwhile, many of the densely populated areas experiencing water shortages are subjected to other, perhaps more complex problems which appear to be, at least in part, a product of their increasing size. Therefore, the expenditure of large sums to supply them with water for indefinite growth appears to merit scrutinous study.An alternative approach designed to minimize both water diversion costs and problems associated with over-populated areas is the stimulation of development in carefully selected regions well endowed with water and other natural resources. One such area and several of its attributes are discussed herein.

Notes: A gravity survey covering 250 square miles and including the Walnut Gulch watershed at Tombstone, Arizona has been conducted. The watershed is one of the experimental areas of the Southwest Watershed Research Center, Agricultural Research Service in Tucson, Arizona.The gravity survey method was selected as the geophysical method that would give a regional picture of the subsurface geology before making extensive surveys by the seismic. refraction method. Basically, the gravity survey method detects and measures variations in the earth's gravitational force. These variations are associated with changes in rock and alluvium density near the surface. Many geologic structures of interest in watershed ground-water hydrology cause disturbances in the normal density distribution which give rise to anomalies.The geology of the watershed is typical of Basin and Range province and contains deep basin fill deposits surrounded on the east, south, and southwest by igneous intrusives, volcanics, and sedimentary rocks. Concealed border faults may have a decided effect on the hydrology of the watershed.Four base stations were established and 360 gravity stations occupied by a Worden Educator* gravimeter loaned from the Geophysics Laboratory of the University of Arizona. Bench marks and large scale topographic maps served as control. Raw field data were reduced to the simple Bouguer anomaly values through the use of a computer program.The gravity survey reveals a 16-mgal. gravity low over the east-central portion of the watershed. This low is interpreted as indicating that about 3200 feet of low density alluvium underlies the area at this point. Gravity highs are associated with mountain ranges and igneous plugs where the more dense rocks occur.

Notes: Recent increased interest in subsurface disposal of industrial liquid wastes in Illinois has shown the need for both geohydrologic and engineering criteria and State regulatory policies for evaluating proposed installations, with the object of protecting other resources, chiefly potable ground water.Favorable geohydrologic conditions–specifically the presence of a variety of permeable formations that contain nonpotable water and are well confined from shallow to great depth–make waste disposal by wells feasible in much of the southern two-thirds of Illinois. Natural safeguards permit disposal wells to be planned with conventional engineering precautions and only a minimal program of preoperational testing.In much of the northern third of the State, the permeable rocks contain potable water to great depth, and there is moderate to high development of the ground-water resource because of urban and industrial concentration. Exhaustive testing, substantial proof of acceptable site conditions, and incorporation of optimum engineering safeguards are considered necessary before the State regulatory agency can authorize installation.

Notes: Comparative costs of ground water were needed for comprehensive planning of water resources development in the Susquehanna River basin in order to appraise the feasibility of alternative sources of water supply. Log-normal plots on logarithmic-probability paper that represented specific capacities adjusted to 180 days of pumping were used to estimate well yields and costs of obtaining the ground water from each of 65 potential aquifers. The 25, 50, and 75 percent probability of occurrence of the specific capacities of successful wells were used in the calculations. The estimated well yields at these probabilities of occurrence were obtained using hypothetical well designs and selected drawdowns. Ground-water costs for the estimated or design yields were calculated using amortized costs of well construction, electrical power costs, and maintenance costs, all obtained from standard sources.The calculated well yields and costs for the 25 to 75 percent probability interval range from 15 to 9,000 gpm (gallons per minute) and from $0.004 to $0.11 per thousand gallons of design yield. The yields and costs group according to aquifer rock type. The calculated costs decrease with increasing well yield and the available yield depends upon the aquifer rock type available. Representative costs per thousand gallons of design yield for selected yields from aquifers composed of different rock types analyzed are: 50 gpm −$0.060 for shale and interbedded sandstone and shale, and $0.050 for metamorphic rock; 100 gpm - $0.043 or shale and interbedded sandstone and shale, $0.037 for metamorphic rock, and $0.032 for carbonate rock; 500 gpm—$0.020 for sandstone, $0.015 for carbonate rock, and $0.012 for glacial sand and gravel; and 1,000 gpm —$0.009 for glacial sand and gravel. Differences in cost to obtain the same yield from different rock types are primarily due to differences in electrical power costs as determined by differences in pumping water levels.If used with caution, the generalized yield and cost estimates for aquifer rock types may have usefulness in estimating ground-water costs and yields in similar humid areas. They are primarily useful for planning and comparative purposes, but not for the actual design of engineering Projects.

Notes: Hazards to ground water may result from adding to water which may infiltrate the soil, or to the soil through which water percolates, wastes from man's life processes; his industrial and commercial activity; or his use of water, fertilizers and pesticides in agriculture. From experimental data it is evident that particulate matter, including bacteria and viruses, do not move far with percolating water in a soil system. The chemical products of biodegradation of organic wastes, however, with a few exceptions such as phosphates, move quite freely and hence reach ground water. Since they are no different than the compounds found in ground waters the effect of domestic use of water is generally to increase the concentration of salts normally present in such waters. From the vast spectrum of compounds produced by the chemical industry and used in industry and commerce comes hazards to ground-water quality such as metal ions, phenols, tar residues, brines, and exotic organics which may through accident, carelessness or waste-water discharge contaminate ground water. Mineralization with nutrients and soluble soil fractions, and possibly, pesticide residues are the hazards from agricultural use. Leaching from solid waste landfills is possible under poor long-term management and might involve chemicals, iron, and various earth minerals. It is concluded that the most serious hazard is the buildup of dissolved solids to levels inimical to beneficial use.

Notes: In this paper, basic design principles for disposal wells are set out and then exemplified by discussion of two recently constructed wells for disposal of very corrosive refinery waste. One well is designed for 700 gpm of waste containing 4200 ppm hydrogen sulfide. The other is designed for 50 gpm of waste containing 32 percent hydrochloric acid. Both wells are in the Gulf Coastal Plain and are completed in a deep, unconsolidated fine sand containing salt water. Screens fabricated from exotic metals were incorporated in the design. Unique combinations of materials were used for the casing.It is pointed out that oil field type completions are often used in disposal well construction, which usually results in low specific injection capacity, high operation and maintenance costs, and short useful life of the hydraulic structure.

Notes: A supply of good-quality water is our most critical natural resource, for our municipal growth and an increasingly healthy industrial base. The economic viability of our farms depends upon it. The locating and development of this resource is the province of the hydrogeologist.The hydrogeologist is more than just a ground-water geologist, for he deals with water in virtually every geologic situation, above-the water table as well as below it, and at the surface as well as underground.The hydrogeologist must of course possess the necessary background in the allied sciences and fluid mechanics, and should know something of the social science aspects of water decision-making. He must be able to work closely with the civil and sanitary engineers, and he must be able to make himself understood to planners.In performing his work he has a responsibility to society, and this is equated with a responsibility to his profession. As Martin Van Couvering has said, the respect that our profession deserves “cannot be bought or solicited; it has to be earned by the right kind of performance.”

Notes: Water well drillers gather information essential to recovery tests as part of normal procedure. Added effort could yield additional valuable information. More care in measurement of water levels both before and after a period of pumping can be used with ground-water formulae to determine approximate well efficiency.A relationship exists between the ability of an aquifer to perform (transmissibility) and the specific capacity of a well. By means of pumping tests, both transmissibility and specific capacity may be measured. The theoretical specific capacity can be obtained based on the measured transmissibility. Well efficiency may be estimated from a comparison between measured specific capacity and theoretical specific capacity.Tests of wells owned by the City of Houston, Texas, were selected for analysis. Test results were compared with curves showing theoretical relationships. From the comparison, wells in the Houston area are not completely developed. It may not be economical to develop a well to 100 percent efficiency, but theoretical relationships should be used in well development.

Notes: An induction-tuned device was designed and tested under a variety of well casing conditions. It can detect casing lengths to within 0.4 to 2.0 inches for casing ranging from 2 to 14 or more inches in diameter which are made of either magnetic or nonmagnetic metals. A casing separation as small as one inch is detectable for 12-inch diameter casing and a four inch or more separation is detectable for 4-inch I.D. casing. These values indicate the range in sensitivity expectable when determining casing separations.Dial readings in microamps are indicated as the ptobe is raised or lowered within a well bore. Readings vary depending whether the probe is centrally located or located to one side. The maximum and minimum dial reading is established for a given casing diameter at the start of a survey. A consistent change in dial reading from previous valves indicate a casing diameter change.The sensing element is a coil whose inductance is changed by varying its proximity to any metallic conductor. A coil and capacitor in parallel make a tuned circuit resonant at 3 K.C. The device includes a transistor in a phase shift oscillator, and a second transistor which acts as a current amplifier, a 0–100 μa d. c. meter driven through a bridge rectifier, capacitors, and other elements. Twelve to 14 volts at 4 to 6 milliamperes or less than 0.1 watt is sufficient to power the device.A maximum meter reading is obtained by adjusting an oscillator to the resonant frequency of the probe. Lowering the probe into a well casing detunes the probe, changing its impedance and the meter reading.All electrical elements are standard except the probe and all materials can be purchased for about $40.00 exclusive of the reel and cable assembly.

Notes: The electrical resistivity method has been a valuable tool used in the discovery of ground-water recharge facilities with percolation capacities in excess of 100,000 acrefeer per year. The procedures used in doing the field work and the methods of plotting the data are described using a typical area where studies were made. Correlations of soil types, recharge rates, and resistivity data for Santa Clara -County are included. Ground-water level data from observation wells are used to measure the regional and long-term effects of the ground-water recharge program.

Notes: Buried valleys are classified into two main types — those valleys completely buried by glacial drift, without present streams along their courses (Type I), and those partly buried or partly exhumed, usually with present streams along their courses (Type II). If a stream is flowing mainly in a Type II valley, the bottom of which is deeply buried by drift, local areas where the stream is cutting bedrock are postglacial channels of derangement. Postglacial channels of derangement, which often can be recognized on a topographic map, reveal that a buried valley (often Type I) exists nearby.

Notes: Ground water of acceptable quality is commonly interspersed with water of inferior quality. Water of inferior quality may be naturally occurring salty water commonly underlying fresh water, or it may be enclaves of contaminated water from wastes that lie in the fresh-water bodies. Disposal of wastes on and in the ground and pumping of water from wells cause a dispersion of contaminated water; migration of contaminated water toward wells may be spontaneously induced by the natural hydraulic gradient, or it may be induced artificially by the cone of depression about one or more wells. Economic methods of determining precisely the boundary zones between contaminated and uncontaminated water are not available. Much reliance is placed on monitoring wells.A prerequisite to monitoring is a synthetic hydrogeologic framework or model in which the behavior of the contaminated water is conceived. Such a conceptual model, using pertinent data that are available, helps to assess the need for monitoring and to guide a monitoring program for optimum results. Unplanned, indiscriminate monitoring of water from wells is expensive, inefficient, and fallible. The need for monitoring will increase in the future; yet, the proper objective is to improve the technology of determining the distribution of contaminated water so that monitoring can be minimized and conducted with optimum results.

Notes: Ground-water development frequently provides a means whereby tremendous new economic opportunities are opened up. If supplies are overdrawn (mined) the ensuing regional economy may be able to afford replacements from more costly sources. In the United States the Salt River Valley of Arizona and the valleys of California provide examples.Two cases are treated in this paper, Israel and West Pakistan. In Israel, besides furnishing more than half of the basic source of water supply, ground-water development provides opportunity for both quantity and quality management, which makes possible use of surface supplies and reclaimed sewage as firm rather than marginal sources. This development will permit the total water resource of this small country, where agricultural production ranks among the world's most efficient, to be utilized effectively down to almost the last drop by the mid 1970's. Israel must then look to desalted water from the sea for-further expansion of its over-all water supply.In West Pakistan a combination of level terrain and leaky canals since about 1890 led to threatened waterlogging and salinity of more than 25 million acres of irrigated land, even though supplies were less than half adequate for good productivity. By the 1950's low yields and increasing population threatened starvation. However, initiation of ground-water development, first by the government and later by private enterprise, has, since 1960, led to construction of 3,500 governmental tube wells of about 3 cfs capacity and 30,000 private tube wells of slightly less than 1 cfs capacity.Results have been dramatic. Agricultural production and use of fertilizer are rapidly increasing, and opening of well development to private enterprise is providing the irrigator with benefits of free competition for his water custom which he did not previously enjoy. Ultimately, besides providing full supplies for an estimated 26 to 30 million acres, drainage and salinity problems will be mitigated if about 50 million acre-feet are pumped each year from ground water including about 28 million acre-feet to be mined from a reserve of about 1,900 million acre-feet. With some difficult surface storage development due to terrain, mining may eventually be reduced. Though an eventual technological solution for the continuing overdraft is not now in sight, perhaps an economy may be built which can afford such a solution when the time comes.

Notes: The effects on flow of a nearby stream from pumping a well can be calculated readily using dimensionless curves and tables. Computations can be made of: (1) the rate of stream depletion at any time during the pumping period or after the cessation of pumping; (2) the volume induced from the stream during any time, both during pumping or after the cessation of pumping; and (3) the effects, both in rate and volume of stream depletion, of any selected pattern of intermittent pumping. Sample computations illustrate the use of the curves and tables. An example shows that intermittent pumping may have a pattern of stream depletion not greatly different from a pattern for steady pumping of an equal volume.The residual effects of pumping, that is, effects after cessation of pumping, on streamflow may easily be greater than the effects during the pumping period. Adequate advance planning that includes consideration of residual effects thus is essential to effective administration of a stream-aquifer system.

Notes: The Piedmont is underlain by igneous and metamorphic rocks, from which it is difficult to locate quantities of ground water adequate for municipal and industrial purposes. Ground-water occurrence and movement in the Piedmont is controlled by topography, recharge and discharge, rock type, fracture systems, and type and thickness of saprolite.Approximately 12 square miles in the Heflin area, Cleburne County, Alabama, were included in this study. Fractures within bedrock are the most effective avenues for ground-water movement in this area, but domestic supplies can be produced from saprolite and alluvium overlying bedrock. Thick saprolite contributes to bedrock-fracture production by absorbing water from streams and rainfall and releasing it slowly to underlying fractures.Seismic methods were used with geologic, hydrologie and topographic data to locate and define favorable areas for drilling. As shown on the seismic sections, faults or fracture systems appear to correlate with depressions on bedrock surfaces associated with thick saprolite zones. Seismic data indicate twenty-five prospective areas for test drilling.Resistivity data were used to confirm seismic depth to bedrock, and to locate gravelly zones in buried stream channels. Some of the buried alluvium is thick enough to be considered a potential aquifer.Twenty-five prospective areas are indicated by geophysical work in the Heflin area. A proposal to drill 10 wells to evaluate the most promising of these areas is presently being considered.

Notes: The Floridan aquifer in northeast Florida is comprised of limestone and dolomite beds of Tertiary age. These formations in ascending order are: the Cedar Keys Formation of Paleocene age; the Oldsmar Limestone, Lake City Limestone, Avon Park Limestone, and the Ocala Group, all of Eocene age; locally the Suwannee Limestone of Oligocene age; and limestone and sand beds at the base of the Hawthorn Formation of Miocene age. The top of the Ocala Group ranges in elevation from 100 feet above sea level to 550 feet below sea level throughout the area.Except in the western part of the area where the Ocala Group is at the surface, impermeable beds in the Miocene to Recent deposits overlie the aquifer and confine the water under artesian pressure. Hard, impermeable beds within the aquifer separate the water-bearing zones. The coefficient of transmissibility ranges from about 50,000 gpd/ft (gallons per day /foot) to more than 1,000,000 gpd/ft and the coefficient of storage ranges from 1.5 × 10−4 to 1.7 × 10−2 in areas where the water in the aquifer is under artesian conditions.The estimated annual recharge averages one-half mgd (million gallons per day) in the western part of northeast Florida and 45 mgd in the south central part. Limited recharge also occurs throughout the central and eastern part of northeast Florida by downward leakage of water through the overlying confining beds. The coefficient of leakance of these confining beds ranges from about 1.7 × l0−2 to 1 ×10−3 gpd/ft3.Natural discharge occurs by perennial and intermittent springs and upward leakage through the confining beds in the areas of artesian flow. Artificial discharge by wells occurs principally in the farming, urban, and industrial areas in the eastern part of northeast Florida.Between 1940 and 1962 artesian pressures declined from 5 to 25 feet throughout the eastern part of northeast Florida.Seasonal declines of artesian pressure of 5 to 10 feet in the farming areas resulted in temporary increases of chloride content of water of 200 to 500 ppm (parts per million). The chloride content of water in the aquifer in the vicinity of Jacksonville and Fernandina has increased from 22 to 1400 ppm in wells more than 1,400 feet deep. Thus far, impermeable zones below the fresh water have prevented serious salt-water contamination in shallower wells at Jacksonville and Fernandiua.

Notes: The significance of the work associated with the protection of aquifers against salt-water encroachment, primarily in the area of Southern California goes far beyond the solution of this local problem. Engineers and planners are now able to turn to the record of extensive practice in the field of artificial ground-water recharge to modify the concepts based on theoretical studies. Thus depleted aquifers, anywhere, can be evaluated as potential reservoirs for the storage of ground water – evaluated as to cost, legal complications, and administrative design in the same way, and on the same basis, that surface-water impoundments are evaluated.The work done on the West Coast in artificial recharge increases the number of alternates that are available to the water planner and, in the long run, this may be the most significant output of the engineering, construction, and operation of the barrier projects.

Notes: Electrical earth resistivity and soil temperature surveys have been conducted in the vicinity of four sanitary landfills in northeastern Illinois to test the possibility of detecting and tracing any chemical or temperature alteration of ground water by leachates from buried refuse. Reference data on water quality, levels, and movement were provided by a system of monitor wells drilled for a hydrogeologic study of the landfills.The resistivity survey, which was in homogeneous silty sand outwash, traced mineralized water from the landfill for a distance of more than 1000 feet. Apparent resistivity values were one fourth those obtained from unaffected areas. Interpretations of direction of ground-water flow and location of discharge boundaries from the geophysical data agree vith interpretations based on the monitor well data.The soil temperature survey indicated the presence of a halo of higher temperatures around the landfill and indicated areas of surface recharge.The geophysical surveys show, in general, that chemically altered water is traceable in uniform earth materials where the depth of the water table is constant.

Notes: The U. S. Geological Survey, on behalf of the U. S. Atomic Energy Commission, performs a broad range of geologic and hydrologic studies related to underground nuclear explosions at the Nevada Test Site. One phase of the studies involved extensive geophysical logging and hydraulic testing in deep exploratory holes at Pahute Mesa, Nevada Test Site. Various geophysical logs and hydraulic testing techniques used in the study are described in this paper.Interpretations of logs and logging techniques depend on factors such as rock characteristics in a particular area, drilling methods, and the objectives of the hydrologic investigations. From experience gained at Pahute Mesa, some qualitative data on rock lithologies and hydraulic conditions in the borehole may be determined by electric, caliper, temperature, and fluid resistivity logs. Quantitative data on the major water-yielding intervals in the borehole are obtained from radioactive tracer or spinner surveys. Interpretations of the geophysical logs have been verified by isolating specific zones in the drill holes with inflatable packers and spacers. These intervals were tested by injection or swabbing of fluid and measuring the resultant change in water level caused by fluid outflow from or inflow to the interval of rock isolated by the packers.

Notes: Portable pumping equipment for sampling of wells, discribed by written text, photographs, and a detailed drawing, has been constructed by the Robert S. Kerr Water Research Center.The equipment can sample to depths of 300 feet at pumping rates ranging between 7 and 14 gallons per minute, with rate variation dependent upon sampling depth.The unit is convenient in size and easy to operate because only one line has to be handled during its operation. This is a wire-reinforced rubber hose that supports the submersible pump, contains the electrical cable, and conveys water.

Notes: The landlocked Republic or Upper Voira lies in the heart of West Africa and comprises a wide lareritic plateau at the south edge of the Sahara Desert. From south to north, the rainfall decreases from about 1.200 mm. to less than 500 mm.; the evaporation increases from a low of 1,945 mm. to 3,385 mm.; and temperatures from 30° C to 34° C.Latentic rocks occur as surficial deposits over much of the reconnaissance area, and generally are ferruginous, hard, and cemented. The underlying bedrock consists primarily of granite and granodiorite with lesser amounts of metamorphics.The so-called “under latérite” materials, consisting of the weathering products of the igneous and metamorphic rocks, constitute the principal aquifers in the investigated areas. These clays and sands generally can be counted upon to yield small supplies of water, adequate for at least domestic and stock use. Large-diameter dug wells are used exclusively to tap the thin water-bearing zones. Where 15 meters or more of weathered material occur above fresh bedrock, water can be found and exploited. A “good” well is one which produces 2,000 litersb per hour.The chief importance of the bedrock as a source of water is that it may yield at least a small quantity of water from fractures at most localities where ir is below the water table.Water in sufficient quantity and adequate quality is not now available to raise the standards of living in the 631 villages in the areas visited. Most of the immediate need can be met by developing ground water from the weathered material through large-diameter dug wells.

Notes: A shallow, wide spread perching layer was isolated in the alluvial profiles of western Fresno County, California. Geologic and hydrologic interpretations are given, based on field and laboratory measurements of the physical properties of this layer. Some of the approaches investigated included using existing electrical logs from irrigation wells, head loss observations in wells and piezometers, core drilling, and core analysis. Differences in alluvial profile permeabilities are shown which result in perched water under the existing field flow conditions. The quantity of vertical flow through the layer is estimated using core permeabilities and hydraulic gradients observed in the field.Hydraulic properties and descriptions for the perched zone are presened which can be used to delineate profile flow limitations at other locations in the San Joaquin Valley. The study may be used in estimating the rate at which this perched water table could rise If, in the future, imported water and changes in irrigation patterns cause a large quantity of water to flow vertically.

Notes: The most commonly practiced method of artificial recharge at present is through basins. This spreading method may not be physically feasible or practicable if land values are high or a shallow, densely compacted layer forms a barrier impeding the direct downward percolation of the ponded surface water.For the case of the latter condition, alternative methods of wells or trenches dug down to the pervious aquifer and backfilled with gravel have been investigated. These were explored from the standpoint of construction and operating cost and hydraulic efficiency as influenced by such factors as the depth to the aquifer, the thickness, depth of saturation, permeability and specific yield of the aquifer, interference of closely spaced wells and duration of continuous operation of the wells or trenches. Furthermore, effects of bacterial growth and chemical composition of the recharge water on the hydraulic performance of wells or trenches are discussed.An economic comparison based on field conditions in a prospective recharge site at Stockton, California, is used to illustrate the developed criteria for relative effectiveness of the two methods.As a general conclusion, it was found that while recharge through trenches would be more efficient hydraulically and economically for the case of very shallow subsurface barriers, wells would become more competitive as the thickness of an impervious top layer increases.

Notes: The horizontal viscous flow model with “infinite” areal extent can be used for almost any well flow problem whether two-dimensional or three-dimensional, steady or nonsteady, single aquifer or multiaquifer. This model can also be used in the field of soil mechanics for subsurface drainage problems. The design includes scale model analysis and the application of conformal mapping techniques in order to simulate an ideal aquifer. Construction, calibration, and test procedures for the model are described. The apparatus has proved to be both a valuable research tool and an excellent teaching aid.

Notes: One of the deepest water-exploration wells in the southeastern United States was completed in 1966 at Jacksonville, Florida. It was drilled to a depth of nearly 2,500 feet to supply geologic and hydrologic information on the deeper unexplored part of the Floridan aquifer. This aquifer consists of a series of water producing zones separated by nonproducing zones. An important new fresh-water producing zone was found, and the contact between the fresh water and salt water was located. The well was completed in three separate zones so that it could be used to monitor the the deeper part of the aquifer to detect any salt-water encroachment. This paper describes the objectives, techniques, and results of drilling the test well.

Notes: A rapid graphical technique for the determination of aquifer transmissibility from a variable discharge pumping test is presented. The data required include the variation of discharge with time during the pumping test and a record of the recovery ar an observation well after the well was shut off. An example using a synthetic well data is provided.

Notes: Comparison of the analysis of 3 and 4 day pumping tests with the analysis of water-level changes due to 18 years of pumping suggests that experience in an area can be a critical factor in determining the transmissivity and storativity of an aquifer.

Notes: The rapidly increasing development of ground-water resources in northeastern Illinois has brought about regional and local problems of water supply, thus creating considerable interest in the feasibility of artificial recharge as a partial solution. Artificial ground-water recharge is considered as a partial solution to regional and local problems of water supply in the primarily metropolitan region of northeastern Illinois. Five artificial recharge facilities are now in operation in the area; their average annual recharge rates range from 25,000 to 395,000 gallons per day (gpd). Several additional areas where artificial recharge may be feasible are identified on the basis of criteria established for the region.An initial study in the Park Forest-Chicago Heights area indicates that recharge to the Silurian dolomite aquifer, the source of water supply in the area, is feasible. This study provides guidelines to aid in additional studies of artificial recharge in northeastern Illinois.

Notes: Two case histories are presented which illustrate that by analyzing drill cuttings or bailed samples, by knowing total depth of a test hole and position of the static water level, and by studying the driller's log, not only can a well's yield be predicted—but also drawdown may be predicted for any well in advance of a pumping test.The estimation of specific capacity (gpm/ft of drawdown) is invaluable in well design, particularly in the United States, where drilling contractors work rapidly and efficiently. Knowledge of probable specific capacity can aid in recommending proper screen length, diameter, slot width, and setting. It will enable cost estimates for proper pump size to be made, for casing requirements to be determined, and also for ultimate well diameter and depth to be determined. Test-pump setting can also be anticipated.Case History No. 1 illustrates the above techniques, and how a new well was drilled, developed, designed, and completed adjacent to a poorly designed and equipped water well. The new well proved to be nine times more efficient (i. e., “better”) than the old well. Reasons for this improvement are shown, and the two wells are compared and contrasted.Case History No. 2 shows data from a constant-rate pumping test following calculation of a well's specific capacity using estimates of aquifer permeability. Analysis of dynamic water-level recovery measurements resulted in a transmissibility of 16,150 gpd/ft compared to an estimated 16,000 gpd/ft from a visual inspection of sand analysis grading curves. The well's specific capacity was estimated to be between 8.4 and 8.9 gpm/ft of drawdown. The measured specific capacity was 8.35 gpm/ft with an efficiency of 85 percent. Actual permeability was 230 gpd/ft compared to the estimated 228 gpd/ft2!Six figures are included showing well construction details, sieve analysis curves, a semi-log plot of recovery measurements obtained during an aquifer pumping test, and graphic representations of approximate permeabilities for granular materials ranging from clay/silt to fine gravel. Six tables give characteristics of samples recovered from two test wells, permeability estimates of the disturbed samples, approximate permeabilities of various granular materials, and specific capacities for 100 percent effective water wells with varying diameters, coefficients of storage, and pumping periods. Three photographs further illustrate the principles enumerated.The methods described can give acceptable results (although they may not be as spectacular as the two detailed case histories) if sound judgement is used; if local conditions are somewhat known; if sampling methods are described; and if the procedures are not abused by expecting extreme accuracy. A reasonable estimate, or perhaps, just a close scientific “guesstimate” is all that should be hoped for by the hydrogeologist and his client in predicting well yields. But these techniques are a great advance over the“forked peach stick” philosophy still used for similar purposes by pseudo-scientists in the United States and foreign countries (although no cases where a dowser or “water witch” has successfully predicted drawdown in addition to yield have come to the attention of the writer).The data in this report are derived from approximately 500 wells or more designed by the author in 26 States and in many locations abroad. Rather good success has been obtained regarding close correlation between estimated and measured specific capacities from a variety of geologic environments and aquifer parameters.