bluuebunny/crossref_metadata_2025 huggingface dataset:
Step‐Drawdown Test Needs Critical Reviewa
Authors: Mogg Joe L.
Published: July 2006

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.
Costs of Wells and Pumpsa
Authors: Ackermann William C.
Published: July 2006

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.
Water Resources and the Urban Environmenta
Authors: Hackett James E.
Published: July 2006

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.
Intergovernmental Planning of Water Resourcesa
Authors: Wilm Harold G.
Published: July 2006

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.
Can Ground‐Water Pollution Be Avoided?a
Authors: Williams James H.
Published: July 2006

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.
Ground Water, Gravity and Rift Valleys in Malawi
Authors: Davis Richard W.
Published: July 2006

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.
Control of Sea‐Water Intrusion in a Ground‐Water Aquifera
Authors: Bruington A. E.
Published: July 2006

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.
Significance of Ground‐Wafer Management Strategy— A Systems Approacha
Authors: Beaver J. A. , Frankel M. L.
Published: July 2006

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.
Methods for Calculating the Cost of Developing Ground‐Water Resources in Appalachiaa
Authors: Wyrick Granville G.
Published: July 2006

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.
Air Pump for Small‐Diameter Piezometers
Authors: Trescott Peter C. , Pinder George F.
Published: July 2006

The engine of a field vehicle can easily be used as an air pump by inserting a commercially manufactured check valve into a spark‐plug socket. Small‐diameter piezometers can be pumped with compressed air from this source. With sufficient air‐line submergence, the air lift method can be used to pump 1‐inch diameter piezometers where the pumping lift is less than 70 feet and 1.25‐inch diameter piezometers where the pumping lift is less than 50 feet. In cases where this method will not work, some of the water contained in a piezometer can be pumped out by pressurizing the piezometer if the formation transmissivity is low and the pumping lift is not excessive. The maximum pumping lift is a function of the rate at which pressure in the piezometer is increased and the rate at which water flows into the formation with increasing head in the piezometer.

The engine air pump is useful in developing piezometers, flushing out stagnant water before taking water samples, obtaining water samples, and creating head differences to initiate slug tests.
Drain Installation for Nitrate Reductiona
Authors: Willardson L. S. , Meek B. D. , Grass L. B. , Dickey G. L. , Bailey J. W.
Published: July 2006

A field experiment has been installed near Firebaugh in the San Joaquin Valley of California to test submergence of drains as a means of denitrification of ground water. Laboratory and field experiments have shown that denitrification occurs in saturated soil where there is ample organic carbon available for bacterial metabolism. Denitrification and dilution of high nitrate ground water were accomplished in the field.
Aquifer Simulation on Slow Time Resistance‐Capacitance Networks
Authors: Rushton K. R. , Bannister R. G.
Published: July 2006

For several years resistance‐capacitance networks have been used to simulate aquifers. Most reported work has been concerned with fast time analogues in which the period under consideracign is represented in micro‐seconds. However the alternative slow time analogue has many advan tages since the electrical experiment takes several seconds. This results in simpler equipment and simpler experimental techniques.

The paper concentrates on the practical aspects or the slow time analogue giving details of the components, describing a method of simulating wells and recharge and comparing measuring instruments. The techniques are illustrated by a simplified example.
A Computer Method for Pumping‐Test Analysis
Authors: Saleem Z. A.
Published: July 2006

The knowledge of aquifer parameters is invaluable for quantitative description of geohydrologic systems and for optimal utilization of ground‐water resources. The classical methods of pumping‐test analysis are mostly graphical in nature and there is room for error in individual judgment in the geographical analysis. The computer method for aquifer evaluation comes under the inverse analysis techniques and is based on the classical principle of least squares. The sum of the weighted squares of differences between the observed drawdowns and the drawdowns calculated using the theoretical drawdown equations for the flow system under consideration is minimized, treating the aquifer parameters as decision variables. The method can be applied to any flow system for which analytical expressions for the potential distribution are known. The method was successfully applied to four pumping tests, two in nonleaky confined flow 1 systems, one in a leaky confined flow system, and one in an anisotropic nonleaky confined flow system. The percentage differences between the values of storativity and of transmissivity arrived at by the two methods are found to be as much as 24‐and 1.6 percents, respectively.
Use of Alluvial Faults in the storage and Retention of Ground Watera
Authors: Williams Dennis E.
Published: July 2006

Alluvial faults are generally treated as impermeable boundaries. Recent investigations of the faults in Califoria's Owens Valley, however, reveal that they are semi‐pervious, or leaky in nature. The rate of ground‐water movement through a semi‐pervious alluvial fault is dependent upon the hydraulic conductivity of the fault gouge, the thickness of this zone, and the water‐level differential across the fault. Optimization of the ground‐water resources in the Owens Valley is currently being practiced using these faults in a controlled RECHARGE‐EXTRACTION‐SALVAGE System. In a system of this type, artificial recharge is induced into the Valley's aquifers upgradient from alluvial fault zones by impounding and diverting the creek flow tributary to the area. Extraction of ground water is effected by means of large‐diameter supply wells located near the faults on the upstream side. Salvage of ground water is accomplished by lowering the water table in the vicinity of these faults, thereby causing phreatic growth to die out. When predicting water levels in the vicinity of semi‐pervious faults, a solution is obtained for the induced water‐level decline caused by backward leakage through the faults.
ModelTests for a Horizontal Well
Authors: Peter Yehuda
Published: July 2006

This paper deals with the ground‐water flow into a drilled well, consisting of a vertical shaft and radially spaced horizontal intake pipes.

It is based on model tests, devised and executed by the author in the Hydraulic Laboratory of the Haile Selassie I University in Addis Ababa, Ethiopia.

The author tested the assumption of linearly distributed inflow into the pipes, based on the steady‐flow theory of Darcy‐Thiem, and found satisfactory agreement between theory and experiment.
The Rock and Bong Techniques of Measuring Water Levels in Wells
Authors: Stewart David M.
Published: July 2006

Measurement of the depth to water in wells can be accomplished by timing the fall of a marble or BB. Depth to water can also be determined in terms of the frequency of the reverberations heard in a well. These two methods are called the rock and the bong techniques respectively. Their theoretical basis, their proper execution, and their usefulness are discussed.
Water Levels in Carbonate Rock Terranesa
Authors: LeGrand Harry E. , Stringfield V. T.
Published: July 2006

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.
Where Does Water Quality Improvement Begin?
Authors: Jones Elmer E.
Published: July 2006

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.
Hydrogeology in Czechoslovakiaa
Authors: Zaporozec Alexander
Published: July 2006

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.
Protective Pumping to Reduce Aquifer Pollution, Glynn County, Georgiaa
Authors: Gregg Dean O.
Published: July 2006

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.
Survey of Interstate and International Aquifer Problems
Authors: Bittinger Morton W.
Published: July 2006

A survey of State water agency and university personnel was conducted to identify and classify interstate and international aquifer problems in the conterminous United States. Questionnaires returned identified nearly 200 of such situations. Of these, 30 situations were classified as being a major problem at the present time. An additional 73 situations were classified as minor at the present time. For those problems that were indicated as being expected to develop within the next five years, 9 were classified as major and 25 as minor. For those problems that were indicated as being expected to develop after five or more years, 19 were classified as major and 42 as minor.
The Role of the U. S. Geological Survey in Waste Disposal Monitoringa
Authors: Callahan Joseph T.
Published: July 2006

The disposal of all types of liquid and solid wastes threatens the health and well‐being of mankind. In recent years the constraints on the disposal of industrial and municipal wastes into rivers and the seas have prompted the disposal through wells into the subsurface. Limestone terrane is particularly amenable to the acceptance of all types of wastes in the cavernous subsurface, and has resulted in widespread contamination of shallow ground‐water resources. Highway salting has caused the contamination of thousands of household wells, causing large‐scale replacement drilling programs in some northern States. A semantics problem also has arisen, because liquid wastes injected into the subsurface have not been disposed of, but rather have been placed in a new environment. They may be in storage, they may be attenuating, or they may be changing character by reaction with the rock mass or formation fluids.

The U. S. Geological Survey has been concerned with the study of ground‐water resources for more than 80 years, and with the problems of radioactive waste contamination since World War II. A newly identified program of investigations of waste emplacement into the subsurface was begun two years ago. The purpose of the program is to develop the ability to predict the fate of any wastes deliberately or accidentally emplaced in the subsurface. The program includes research contracts and grants with universities and governmental organizations as well as in‐house research.
A Basin Study of Ground‐Water Discharge from Bedrock into Glacial Drift Part I—Definition of Ground‐Water System
Authors: Kent Douglas C. , Sendlein Lyle V. A.
Published: July 2006

A regional preliminary ground‐water investigation was conducted in the Upper Skunk River Basin near Ames, Iowa. A systematic basin approach integrating geological, geophysical, ground‐water, and water quality investigations was used to study this 800‐square mile basin. The data were compiled in such a manner that first, second and final approximation maps could be constructed. Interpretation of first approximation maps led to a field program which resulted in the second approximation maps. Examination and comparison of the second approximation maps through a system of acetate overlays pointed to problem areas which with further geophysical and geological field checks led to construction of the final approximation maps.

A complex system of bedrock channels were defined using electrical resistivity, shallow seismic refraction and geological methods. A series of map overlays define the bedrock topography, the subcrop geology, the piezometric surface, the sand and gravel thickness, the distribution of water quality, resistivity data and regolith lithology.

Hydraulic continuity between a partially‐confined bedrock aquifer and channel and shallow sands is indicated from a comparison of piezometric and water quality maps. The similarity of bedrock and piezometric surfaces is evidence of discharge from the bedrock into the channel sands and gravel. Finally, a bedrock recharge map was prepared in order to define zones of ground‐water recharge from the bedrock.
Well Losses Due to Reduced Formation Permeability
Authors: Karanjac Jasminko
Published: July 2006

Steady‐state flow to a single well fully penetrating a confined isotropic aquifer is analyzed. The hydraulic conductivity of the aquifer changes exponentially from a minimum value at the well face to a constant value in the “undamaged” aquifer. An‐equation for laminar flow well losses that are due to a decreased permeability in the vicinity of the well is obtained. The well loss depends upon the pattern in which permeability changes. The integral expressing the well loss is evaluated numerically. The results are presented in a graph with nondimensional parameters and could be used for engineering evaluation of the laminar well loss.
The Use of Gamma Logs in Determining the Character of Unconsolidated Sediments and Well Construction Featuresa
Authors: Norris Stanley E.
Published: July 2006

Gamma logs, by revealing differences in the radiation intensity of unconsolidated sediments, can provide important information on the depth and sequence of beds penetrated by a cased well. In some instances the log of a well drilled into a sand and gravel aquifer can indicate the interval, or intervals, most favorable for screening. Changes in logs made before and after a well is screened and developed can show zones in the screened interval where most development occurred, and provide valuable clues as to the overall effectiveness of development.

Although little used at present, gamma logging holds promise of becoming an important tool in hydrologic studies and in the well construction industry. More testing and possibly standardization of equipment is currently needed, along with experimentation in logging techniques, to improve the method. Field correlation between logs and drilling samples are necessary to improve the accuracy of log interpretation.
Ground Water and Land Values in Southwestern Kansasa
Authors: Lee Samuel H. , Bagley Edgar S.
Published: July 2006

Ground‐water irrigation has developed rapidly in the High Plains region of the United States, especially in Texas since the 1930's and more recently in western Kansas. Although most land sales transactions do not show the water value separate from the dry land value, the availability of ground water has greatly affected land values. This study measures this effect by two methods for an area of southwestern Kansas where ground‐water irrigation has become important.

The purchasers of all farm land sold in the selected area between 1962‐67 were surveyed to obtain information on sale price and numerous factors which it was thought might have a bearing on the land value. One method of measuring the effect of ground water on land value involved matching a number of tracts not known to have available ground water for irrigation with an equal number having ground water. Since other factors were matched as closely as possible, the differences in land value were attributed to water. The second method was multiple regression in which total tract land value and land value per acre for some 160 tracts were related to several factors–soil and topographic conditions, tract size, availability of ground water for irrigation, nearness to elevator, mineral rights, and wheat allotment. Both methods produced approximately the same results–for the period studied the availability of ground water for irrigation contributed $95 to $100 per acre to the value of the land.
The Use of Resistivity Techniques to Delineate Acid Mine Drainage in Ground Water
Authors: Merkel R. H.
Published: July 2006

A resistivity survey was run in an area of good geologic control to determine if resistivity is a viable technique for delineating aquifers contaminated with acid mine drainage. Results show that due to the high conductivity of the acid water, it makes an excellent target to define electrically. Aquifers polluted in this fashion were traced from their surface expression back under clays, shales, and coal toward the point of origin. Based on these results along with chemical analysis of streams and ground‐water samples, techniques are presented for the periodic monitoring of the ground water through surface resistivity techniques to determine both the extent and degree of contamination.
Physics of Brine Coning Beneath Skimming Wells
Authors: Sahni Brij M.
Published: July 2006

The purpose of this paper is to elucidate the phenomenon of brine upconing beneath a discharge well partially penetrating an unconfined aquifer in which fresh water is underlain by saline water. In order to predict the maximum uncontaminated fresh water production for given aquifer conditions and well geometry, the potential distribution in the flow region must be known. However, since the partial differential equation describing the flow is nonlinear and so are the boundary conditions, it is not possible to arrive at an exact analytic solution to the problem. Therefore, a less rigorous but tractable approach is to solve this problem using simplifying and physically plausible assumptions. A comparative study is made of the approximate analytic solutions available at the present time and the validity of the assumptions used is evaluated. Factors affecting the stability of the brine cone beneath a skimming well and conditions leading to entrainment of salt water along with fresh water production are also discussed.
A Practical Method for the Sanitarians'Review of Design of Small Public Water‐Supply Systemsa
Authors: Courchaine C.
Published: July 2006

The design of small water systems requires the application of basic hydraulic principles. To prevent excessive head losses in piping systems created by pyramiding peak flows, the Cross method of successive approximations is used. This is a relatively simple means of checking the ability of the system to supply an adequate quantity of water at sufficient pressure. An example problem is worked out in detail to show how the method is applied to a trailer coach park water distribution system.

Hydropneumatic storage tanks do not operate at maximum efficiency without prepressuring. Since Boyle's Law is applicable to all gases including air, it is used to determine the amount of prepressuring required to obtain the greatest amount of water from storage between pump cycles at predetermined pressure settings. A graph has been developed to determine the volume of water in a tank at various levels of prepressuring.
Starting Conditions for Aquifer Simulations
Authors: Rushton K. R. , Wedderburn L. A.
Published: July 2006

This paper discusses the importance of starting an aquifer simulation from correct initial conditions. The errors that will arise if the simulation starts from zero or average heads are determined. Recommendations for minimizing these errors are made.
Geologic Classification of Aquifers
Authors: Blank Horace R. , Schroeder Melvin C.
Published: July 2006

This classification of aquifers is based upon the properties of rocks which affect ground water. In any region the rocks may be consolidated or unconsolidated. They may be uniform in lithology, or they may consist of alternating layers of different lithologies. They may have been tilted, fractured, or altered in various ways since their formation.

Consequently the occurrence of ground water depends not only on the fundamental nature of the rocks but also on their geologic history. The ground water may be found under confined (artesian) or unconfined (water table) conditions. The permeability of an aquifer may be uniform, or it may vary in some regular way, or it may be very irregular because most of the water is in secondary openings.

As most geologic situations do not fit well into precise categories, some aquifers may fall into more than one subdivision of this classification.
Salt Water Intrusion in the Summerside Area, P.E.I.
Authors: Tremblay J. J. , D'Cruz J. , Anger H.
Published: July 2006

Salt water intrusion is an acute problem in the coastal areas of Prince Edward Island. In the town of Summerside, ground‐water supplies are developed from an aquifer hydraulically connected with the sea. Over the past ten years, there has been progressive contamination of the aquifer, particularly in wells close to the seashore.

Investigations including test drilling, aquifer testing and chemical studies were undertaken in Summerside to study the nature and extent of the salt water intrusion.

Landward encroachment of the saline water is aided by the relatively high transmissivity of the fractured Permo‐Carboniferous sandstone which comprises a semiconfined aquifer. Two separate zones of salt water contamination exist—namely an upper zone from a depth of 0 to 80 feet caused by a landward hydraulic gradient of the fresh water due to heavy pumping and a second zone at a depth of 350 to 400 feet due to intermittent pumping resulting in a raising and thickening of the zone of diffusion. The extent of salt water intrusion is depicted, using hypothetical sections.
Increasing Well Yield with Hybrid Wells
Authors: Helweg Otto J.
Published: July 2006

Hybrid wells (a type of collector well) offer a method of increasing the specific capacity of a deep well. A regular deep well is combined with a gallery constructed similar to the qanats, a labor‐intensive technology found in the Middle East. Qanats, tunnels that tap ground water for water supplies, are described. The author explains: (1) the method of constructing hybrid wells, (2) some theoretical considerations using the nonequilibrium equation for pumping tests and the Donnan equation for drain design, and (3) the economic gains from hybrid wells.
Evaluation of a Shallow Leaky Water Table Aquifer in a Subhumid Region of France
Authors: Saint‐Pé Max A.
Published: July 2006

The Arcachon Bay Plio‐Quaternary aquifer, located in a flat poorly‐drained region which receives one m annual precipitation, has a shallow water table which impedes agricultural development. It is composed of a 50‐100 m thick body of well‐sorted clean sand and gravel which has excellent hydrodynamic properties and much fresh ground water in storage. This affluent aquifer is underlain by, and interconnected with, a relatively poor calcareous aquifer of Miocene age.

Leakage to the Miocene aquifer, inferred from geologic and hydrogeologic observations, was calculated by water budgeting and Darcy's law to be on the order of 1.5 m3/s. This rate, about 15 percent of the annual precipitation, is nearly half the recharge rate to the Plio‐Quaternary aquifer.

Schoeller's chloride method was used to estimate recharge to the Plio‐Quaternary aquifer, and indicated that this recharge amounts to more than 35 percent of the annual precipitation. The calculation of the water budget supported this finding. The evapotranspiration rate, based on Thornthwaite's method, is more than 55 percent of the annual precipitation. High recharge and evapotranspiration rates, a direct consequence of the relief, permeability of soils, and occurrence of hot summers, are coupled with a low surface runoff.

Exploitation of the Plio‐Quaternary aquifer can be planned confidently for irrigation and water‐supply purposes. Drainage improvement, needed for extensive farming of the lands, will also result from such exploitation. These development measures are suggested to be tailored and staged in the framework of the master plan aimed to develop and conserve the Arcachon Bay area and the region it is part of.

Descriptors: subhumid environment, shallow water table, multiple‐aquifer systems, leaky aquifers, Darcy's law, aquifer recharge, Schoeller's chloride method, water budget, ground‐water quality, environmental hydrogeology, development and conservation.

Identifiers: shallow leaky aquifers in subhumid environment.
Flow to Wells Near Streams in the Presence of Delayed Yield from Storage and Analysis of Pumping Test Data
Authors: Yotov I. G.
Published: July 2006

A solution is obtained for drawdown around pumping wells in aquifers near streams in the presence of delayed yield from storage using the image theory. Two methods (the second one with two variants) are presented for determining the aquifer constants. The first method is based on the type curves for the initial moments of pumping and for later ones. The Carson‐Laplace transforms of drawdown field data are required for applying the other method. A field example Ts used for illustration.
Ground‐Water Nitrate Pollution in Rural Areas
Authors: Walker William H.
Published: July 2006

In humid regions, chemical pollutants such as nitrate readily enter surficial aquifers as slugs during nongrowing season precipitation recharge periods and move slowly through the aquifer to nearby drainage tiles, streams, or pumping wells. Little mixing, with native ground water seems to occur, and for this reason, fairly small quantities of pollution in bulb form may enter a well as a high‐concentration slug long after its initial entry into the aquifer. Nitrate slug concentrations in excess of 6000 ppm have been delineated in one surficial aquifer in Illinois.

Recent ground‐water pollution studies indicate that trees and plants may temporarily store large quantities of nutrients during the growing season for release to aquifers during subsequent nongrowing seasons. Considering this, it appears imperative that farm fertilizer application and human or animal waste disposal on farmlands be limited only to the growing season of each year and only in quantities that will not ultimately cause ground‐water nitrate concentrations to rise above toxic levels.
WHAT ABOUT GROUND WATER?
Authors: Heath Ralph C.
Published: July 2006

EDITOR'S NOTE: The following article by Ralph C. Heath which appeared in the January 1973 issue of the North Carolina Engineer is another excellent example of how ground‐water geologists and hydrologists should and must speak out in their communities in support of ground‐water development.
Effects of Well Injection on a Basaltic Ghyben‐Herzberg Aquifer
Authors: Hargis David R. , Peterson Frank L.
Published: July 2006

In recent years, the practice of artificially recharging wastewater such as storm runoff, sewage effluent, and various industrial wastes into the subsurface has become of growing importance in Hawaii. In 1970 the Kahului Development Company began construction of a collection basin and four deep injection wells for the disposal of storm runoff from a residential development in Kahului, Maui. This presented a unique opportunity to evaluate the response of a basaltic Ghyben‐Herzberg aquifer to well injection, and to measure the rate of movement of injected water in the aquifer. The results of pumping and injection tests of one completed well and one test hole indicate that the finished injection wells should be able to transmit sediment‐free water at rates in excess of 5500 gallons per minute per well. Observation well measurements indicate that injected water moves at a gross velocity of one foot per minute in the basalt aquifer in the vicinity of the injection wells.
Ground‐Water Quality Models: What They Can and Cannot Doa
Authors: Evenson Donald E. , Orlob Gerald T. , Lyons T. Clark
Published: July 2006

The development and application of mathematical models to simulate water quality behavior in ground‐water basins is at a very youthful stage. There is still much to be learned and a great deal of experience to be gained. However, in the last few years, models have been developed to simulate conservative and some nonconservative constituents under both saturated and unsaturated soil conditions. In addition, models have been found to provide additional information for calibration of quantity models, to identify major data gaps and deficiencies, to be useful in the design of data collection programs and in the interpretation of collected data, to be valuable to watershed planners and managers through evaluation of alternative regulatory policies, physical facilities and management operational plans, and to point out where future research efforts are needed.
Protracted Recharge of Treated Sewage into Sand Part II—Tracing the Flow of Contaminated Ground Water with a Resistivity Survey
Authors: Fink William B. , Aulenbach Donald B.
Published: July 2006

To aid in determining the direction of ground‐water flow after the effluent from the Lake George Village sewage treatment plant is discharged onto natural delta sand beds, resistivity studies were made in the soil (sand) in the vicinity of the recharge beds. Ground water having high dissolved solids is identified as producing lower resistivity readings. The sewage effluent has a higher dissolved solids content than the existing ground water in the area. The path of the recharged sewage effluent, as identified by lower resistivity readings, appears to flow in a northerly direction from the sewage treatment plant along Gage Road toward West Brook. Due to interferences, the resistivity studies could not show whether the high conductivity ground water flows into or under West Brook.
Tests of a Ground‐Water Optimization Technique
Authors: Remson Kenneth A. , Aguado Eduardo , Remson Irwin
Published: July 2006

Results obtained from a linear programming ground‐water management model are tested against those obtained using numerical and electrical analog ground‐water models. The optimal distributions of pumping and head as predicted by the management model are verified.

An improved optimal solution could be obtained by reformulating the management model using different constraints or a finer grid spacing.
Protracted Recharge of Treated Sewage into Sand Part III—Nutrient Transport Through the Sanda
Authors: Aulenbach Donald B. , Ferris James J. , Clesceri Nicholas L. , Tofflemire T. James
Published: July 2006

Upon the information provided by the resistivity survey indicating that the most probable direction of flow of the sewage effluent discharged onto the sand beds at the Lake George Village sewage treatment plant is northerly along Gage Road toward West Brook, a survey was made of the West Brook flood plain, both upstream and downstream from Gage Road. Considerable seepage was found emanating from the base of the sand hill which delineates the West Brook valley. The high dissolved solids of this seepage plus other chemical parameters and the configuration of the land suggested that this seepage represented the effluent applied to the sand beds. Wells were placed in the sand beds and between the beds and West Brook. Measurement of the quality of the ground water in these wells indicates that phosphates are effectively removed in passing through approximately 2,000 feet (600 m) of sand, that chlorides are essentially unchanged, and that organic and ammonia nitrogen are effectively converted to nitrate which is not removed. Phage particles were also found. Substances not removed exerted an influence on the quality of water in West Brook. An additional source of chloride appears to be salt stored at the nearby highway department garage. This interferes with the use of chloride as a tracer of the sewage treatment plant effluent.
Deprivation Contribution and Interference Effects of Multiple Wells in a Common Aquifer
Authors: Harp J. F. , Laguros J. G.
Published: July 2006

The purpose of this paper is to present a method of assessing ground‐water interference effects of multiple wells upon any given well in an aquifer. The method specifically relates to depleted aquifers and attempts to assign the responsibility for the depletion effects to all users on a reliable basis. This basis entails the fundamental relationships between the pertinent variables and is not a simple percentage of water usage rates. The method takes into account both flow magnitude and radial distances from all users to the given depleted well. Large flows at longer distances, in general, affect a given well less than smaller flows at closer distances.

The methodology applied in this paper was developed as a result of a legal suit where relative responsibility among several users for depletion effects had to be assigned. The method will assign the effects, or deprivation contribution, of all water users on any given well in an aquifer common to all the wells. The limitations of the method are also discussed.
Approximation for Steady Interface Beneath a Well Pumping Fresh Water Overlying Salt Water
Authors: Haubold Reiner G.
Published: July 2006

A mathematical expression was developed which would approximate the steady position and shape of a sharp, upconed interface between fresh and salt water in an aquifer when the fresh water only is being pumped from a well. The computation of the interface shape was based on an empirically derived modification of Muskat's approximation for the height of the cone beneath a well. Differing depths of well penetrations and their effect on the upconed interface were investigated with the approximation. The computed interfaces were compared with corresponding interfaces determined experimentally in a Hele‐Shaw model. Close agreements could be achieved for interfaces which penetrated as much as 50% of the distance between the bottom of the well and the initial interface position. Changing the length of the producing interval of the well while keeping its pumping rate constant did not have a significant influence on the shape or position of the upconed interface. Even though the shape and position of the upconed interface could be approximated, a refinement of the analytical methods used in deriving the approximation for the interface may be necessary before it can be applied reliably.
Ground‐Water Quality in the Shiraz Basin, South Iran
Authors: Nejand Said , Khan Rashid A.
Published: July 2006

Ground water of Shiraz alluvial basin in Zagros range (south Iran) shows three principal anion types, namely chloride, sulfate and bicarbonate. Intermediate types between these groups are also present, which seem to represent modifications in ground water due to diagenesis.

Possible chemical origin of the ground water is mainly due to two major processes either acting individually or collectively, i.e. solution of minerals of the geological formation and mixing of ground water accompanied by the precipitation of some constituents such as calcium.
Filter‐Pack Installation and Redevelopment Techniques for Shallow Recharge Shaftsa
Authors: McCormick Robert L.
Published: July 2006

The potential for artificial ground‐water recharge through shallow shafts is being conducted at the Leaky Acres Recharge Project in Fresno, California. The research is directed toward developing methods for constructing and placing filter‐pack materials and procedures for periodically cleaning filter materials to regenerate initial intake rates. This report presents preliminary results of two differently constructed shallow shafts.

Over a period of 94 days, 50.8 X 103 cu m (13.4 million gals) of screened canal water was recharged. Redevelopment with a submersible pump regenerated one shaft to 109 percent of its original intake rate. Piezometric observations indicated that most of the clogging occurred within the filter‐pack material.