ALBERT

Notizen: 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.

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

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 With proper pumpage distribution it is conceivable that there is sufficient water that can be withdrawn (mined) in excess of natural recharge to meet demands through the year 2020.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Notizen: Ground-water flow models developed for the flow systems around Bass Lake and Nepco Lake, Wisconsin, show that models can be useful tools for estimating lake seepage rates. A two-dimensional profile model for Bass Lake illustrates that the ratio of horizontal to vertical hydraulic conductivity of the aquifer around the lake is related to both the magnitude of vertical hydraulic gradients near the lake and the distribution of seepage from the lake as a function of distance from shore. The model also shows that it is important to know the vertical hydraulic conductivity of littoral lake-bed sediments to estimate lake seepage rates.A three-dimensional model constructed for an unusual ground-water flow system around Nepco Lake provides a more realistic simulation of the flow system than does a comparable two-dimensional model. Both models were useful for identifying additional data that could be used to quantify the ground-water portion of the lake's water budget more accurately. It is suggested that a combination of two-and/or three-dimensional models could be used to estimate seepage rates at many lakes for which sufficient data exist.

Notizen: A digital model of a buried channel aquifer contaminated by hydrocarbons is used to evaluate development alternatives. The response to ground-water pumping is critical because the hydrocarbons cause taste and odor problems. The source of contamination is an abandoned pit used to dispose of coal tar residues from an old coal-gas plant. The hydrocarbon residues overflowed the pit, migrated a short distance and seeped into flood plain soils. The downward movement of the hydrocarbons stopped at the water table but some dissolved into the ground water. Three general approaches taken to evaluate management alternatives include: (1) regulation of pumping of the city wells and of drawdown, and recovery periods are considered and the model stressed with various pumping rates and times; (2) construction of a pumping trough barrier is considered and a hypothetical control well is simulated; (3) new well field developments in various locations are considered. Results suggest that there is no way to prevent movement of contaminants to the well field. The only feasible solution is the removal of coal tar residues from the source area and construction of a pumping trough barrier.

Notizen: Increased attention is being directed toward the investigation of tight zones in relation to the storage and disposal of hazardous wastes. Shut-in tests, slug tests, and pressure-slug tests are being used at the proposed Waste Isolation Pilot Plant site, located in southeastern New Mexico, to evaluate the fluid-transmitting properties of several zones above the proposed repository zone. Apparatus used to conduct these tests includes a pressure-transducer system connected to a recording device at the land surface. All three testing methods were used in various combinations to obtain values for the hydraulic properties of the test zones. Multiple testing on the same zone produced similar results. Transmissivities determined by these tests range from 0.00001 to 10 feet squared per day (.000001 to 1 meter squared per day).

Notizen: Organic solvents, including 1,1,1-trichloroethane at concentrations up to 40,000 ppb, were detected in the Old Bridge aquifer under an industrial plant in South Brunswick Township, New Jersey. A hydrogeologic investigation defined the ground-water flow system and a plume of contamination which extended, at a concentration of at least 100 ppb, for a distance of about 1000 feet down-gradient of the plant. A contamination abatement system was designed and installed to prevent this plume from reaching a municipal well located about 2500 feet from the site. The system includes seven extraction wells and a water treatment facility. The locations of the extraction wells and their combined pumping rate were determined in part by a computer simulation of the aquifer, which was subsequently checked by a 20-day pumping test of the system. The on-site treatment facility uses two cooling towers in series to air-strip the volatile organics, and two infiltration ponds to return the treated water to the aquifer. The abatement system has been operating for about 10 months. Ground-water monitoring results show that the plume is now significantly smaller and less concentrated than before the abatement system was installed. It is projected that in several years the aquifer will be largely decontaminated.

Notizen: Pumpage from shallow aquifers, primarily dolomite bedrock, in northeastern Illinois has exceeded estimates of ground-water recharge in extensive areas creating concern that ground-water recharge estimates are too low. Pumpage increased 92 percent during the period 1966-1978 and was 61.7 million gallons per day (2.33 × 108 liters/day) during 1978. During the period 1966-1979 water level declines exceeded 30 feet (9.14 meters) in some areas. Based on a ground-water budget study, it was determined that recharge estimates were in the right order of magnitude and pumpage in excess of recharge was balanced by water taken out of storage from the shallow aquifers. A specific yield of 0.017 was determined for the dolomite bedrock aquifer based on the ground-water budget study.

Notizen: Thirty-three wells and two springs yielding high chloride water from granitic rocks define a northwesttrending lineament, which extends for 60 miles (100 km) along the western Sierra Nevada foothills of Fresno and Madera Counties. Geochemical evidence indicates that many of the constituents in this water are marine connate in origin. However, the connate water has been strongly diluted with meteoric water. The connate water is believed to have been derived from Paleozoic and early Mesozoic marine clastic rocks (now metamorphosed) in the Sierra Nevada. The lineament marks the location where marine connate water has migrated upward from these rocks along an eastward-dipping fault zone. A capping of granitic rocks has enhanced the persistence of this connate water for millions of years. The lineament may be structurally related to the Oakhurst-Fine Gold fault zone, which it parallels for approximately 15 miles (25 km). There is a remarkable correlation in the Oakhurst area between wells yielding high-chloride water and fracture trends determined from aerial photographs. High chloride ground water is present only in topographically low areas, where little flushing by meteoric water has been possible.

Notizen: This is the second of two articles on calculator programs for inverse solutions of the Theis equation.Newton's method is used to develop an iteration formula for the determination of transmissivity and storage coefficient values from a combined Theissian expression that incorporates the information contained in two independent aquifer test data point sets.The algorithm is used in a polynomial-based program for Hewlett Packard HP 67/97 calculators that is designed to process data corresponding to the full practical range of Theis well function arguments and to accept measurements from one or two observation wells, or from entirely different tests of a given aquifer. Program modifications providing for series-based well function calculations are appended, and example calculations are shown.

Notizen: The major water-bearing units in the Houston district are the Chicot and Evangeline aquifer systems. Both systems consist of discontinuous layers of unconsolidated sand (aquifers) separated by clay layers.Extensive pumping has caused large declines of potentiometric surfaces in and around Houston. The declines have caused both the compaction of clay layers, which has resulted in land-surface subsidence, and the movement of salt water towards Houston.During the early 1960's, an electric analog model of the district was made. The model simulated water-level declines; but more importantly, the model indicated that the available data and conceptual model of the hydrologic system, consisting of two aquifers, were not totally adequate to allow simulation of the ground-water systems.During the early 1970's, a second electric analog was built. The second model used new data and a conceptual model consisting of two aquifer systems simulated water-level declines quite accurately, but the model was unable to accurately simulate the spatial distribution of water yielded from clay storage.A digital model was then developed during 1979 to simulate the hydrology of the district. The digital model used five layers and accurately simulated the hydraulic heads in both aquifer systems and land-surface subsidence.

Notizen: Marquardt algorithm has been used for estimating aquifer parameters from pump test data in nonleaky and leaky aquifers. It emerges from the study that in spite of poor initial estimates, the convergence is quick; and the residual square error, for the difference between the observed drawdowns and those calculated from parameters estimated using Marquardt algorithm and the known methods, is minimum in the case of Marquardt estimates.

Notizen: The geochemistry of a very permeable ground-water system containing calcium sulfate was studied to determine the present rate of dissolution. An estimate was made of the chemical composition of water recharging the system and the difference between that estimate and the composition of the ground water in the system was used to determine the minimum amount of calcium sulfate being dissolved under existing hydrologic conditions. This result was used, with published data on rates of calcium-sulfate dissolution, to determine the effective surface area involved in solution processes. Results indicate that flow in this system is through large solution openings, which are growing larger at a rate of a few tens of millimeters per year.

Notizen: Due to inexperience on the part of those assigned to purchase computer facilities for water resource tasks, a poor or unacceptable choice of equipment is often made. The political realities of introducing new computing equipment into a firm which has several departments which will vie for the use of that equipment must be faced.The size, complexity, and capabilities of the machine to be purchased as well as the software and personnel involved must be considered carefully in relation to the specific tasks at hand. The bidding process, demonstrations, and reference materials offer some assistance in deciding among the often confusing array of systems available on the market.

Notizen: Enjebi Island on Enewetak Atoll has been the site of extensive hydrological, geological and geophysical studies. Tidal lag, tidal efficiency and water levels have been measured in 24 wells ranging in depth from one m to 90 m (3–290 ft). Hydraulic conductivity has been measured both on laboratory samples and by aquifer testing in the field. Theoretical ground-water tidal responses have been calculated using a model based on horizontal propagation of tidal signals. Comparison of field observations and model results indicates that the observed results are not consistent with horizontal tidal propagation and that the hydraulics of the system are probably controlled by vertical coupling between the unconsolidated surface aquifer and an underlying aquifer of more permeable limestone. Results from other islands of Enewetak, Bikini and Kwajelein Atolls are comparable, and suggest that vertical transport between layered aquifers is an important feature of atoll ground-water hydrology at least throughout the northern Marshall Islands.

Notizen: In an investigation of the hydrogeology of bedrock valley fills in northeastern Wisconsin, it was determined that the yield and spatial distribution of glacial aquifers are controlled by bedrock topography and glacial geology. Lithologic control for identification and classification of aquifer units was obtained from several hundred drillers' logs calibrated by auger borings and interviews. Transmissivities of drift aquifers calculated from specific capacity tests using Jacob's equation agree well with estimates made from lithologic logs. Seismic refraction and gravity surveys were coupled with well log data to derive a bedrock elevation map. Vertical variability maps calculated from the lithologic logs show that bedrock topography strongly influences the distribution and character of glacial units, and clearly delineate the two glacial aquifer types present, valley and morainal units. Morainal units parallel the Late Wisconsin end moraine trends, while valley units are perpendicular to the moraines. The morainal units are small ice-contact features such as kames, fans, and deltas. The valley units are stream deposits and may have been deposited subglacially. Valley aquifers are the most productive units. Using lithologic and geophysical data, and statistical analysis, a predictive depositional model can be proposed. This conceptual model allows knowledge of bedrock topography to be coupled with glacial geology to predict the spatial distribution of glacial aquifers.

Notizen: A quantitative approach to risk management for accidents in light water nuclear power reactors is proposed to serve as one focus for discussion. In this proposal risk management is divided into two major tasks: the predominantly social and political task of setting the safety goals and the technical task of estimating the risks and deciding whether the safety goals have been met. The proposed safety goals include limits on the following: risk to the individual of early death or delayed cancer death; overall societal risk of early or delayed death; and the frequency of core melt accidents as well as the frequency of containment failure, given a core melt. Also included are a small element of risk aversion and an “as low as reasonably achievable” (ALARA) approach with a cost-effectviness criterion which includes both economic and health effects.

Notizen: This paper develops a descriptive framework for siting large scale technological facilities such as liquefied natural gas (LNG) terminals, and suggests ways of using analyses to improve the process. A key feature of these problems is that they involve relatively new technologies where there has not been a long history with which to construct a statistical data base. Hence the interested parties will each have different estimates of the probabilities and losses associated with events that affect the environment or safety of the population. The decision-making process can be characterized as a sequence of decisions, subject to change over time, which are influenced by exogenous factors and new legislation. Each of the separate decisions involves an input phase and an interaction phase. The input phase specifies the relevant alternatives and attributes associated with a particular decision. The interaction phase focuses on the nature of the conflicts between the different parties in evaluating the alternatives. Conflicts are often difficult to resolve because each stakeholder in the process has his own objectives, a limited information base shaped by these objectives and scarce computational resources. We illustrate the above descriptive framework through a case study of the LNG siting process in California. The paper then explores possible ways of improving the input and interaction phases through more structured analyses. Specific attention is given to the role of decision analysis, the analytic hierarchy process, examining assumptions, and the use of interactive computer models for scenario generation. The paper concludes by suggesting future research needs on designing policy instruments for helping to reconcile conflicts between the vying interest parties. Promising areas for more problem-focused research include the role of insurance and compensation schemes.

Notizen: The purpose of this paper is to provide the main results of a study concerning the risk of chlorine transport by train in France. The specific problem of chlorine transport is presented in the framework of a general model for assessing the risk in the transport of dangerous materials. The probability of accidents followed with a chlorine release involving fatalities are put in perspective with other risks having potential health effects on the public. Two types of application of the model are envisaged in relation to the management of risk: the selection of protective measures through a cost-effectiveness approach and the use of the model for a better planning of decisions in an accident situation.

Notizen: In recent years, benefit-cost analysis has been increasingly applied to large societal decision problems (such as developing a fast breeder energy economy) which involve both risks to society and analysis of very long-term consequences possibly extending over many human generations. This paper examines the philosophical underpinnings of the technique which is a special case of utilitarianism, and compares implications of the technique to those arising from alternative ethical systems in analyzing questions of public safety. Ethical systems which emphasize the good of the whole, such as utilitarianism, are shown to differ sharply in decision outcomes from those which emphasize the rights of the individual, such as libertarianism. It is suggested that benefit-cost analysis should be broadened to include alternative weightings of benefits and costs consistent with a variety of ethical views.

Notizen: An early attempt to measure risk was the 1738 paper of Bernoulli in which he describes the well-known Saint Petersburg paradox. Subsequent writers have considered this game to draw conclusions about the nature of risk or to test newly devised risk models. We analyze the paradox, evaluate various theories which have been advanced to resolve it, and briefly examine the implications of these theories on the wider area of risk analysis.

Notizen: If the point of view is adopted that in calculations of real-world phenomena we almost invariably have significant uncertainty in the numerical values of our parameters, then, in these calculations, numerical quantities should be replaced by probability distributions and mathematical operations between these quantities should be replaced by analogous operations between probability distributions. Also, practical calculations one way or another always require discretization or truncation. Combining these two thoughts leads to a numerical approach to probabilistic calculations having great simplicity, power, and elegance. The philosophy and technique of this approach is described, some pitfalls are pointed out, and an application to seismic risk assessment is outlined.

Notizen: A method is presented for projecting mortality rates for certain causes on the basis of observed rates during past years. This method arose from a study of trends in age-specific mortality rates for respiratory cancers, and for heuristic purposes it is shown how the method can be developed from certain theories of cancer induction. However, the method is applicable in the more common situation in which the underlying physical processes cannot be modeled with any confidence but the mortality rates are approximable over short time intervals by functions of the form a exp (bt), where b may vary in a continuous, predictable fashion as the time interval is varied. It appears from applications to historical data that this projection method is in some cases a substantial improvement over conventional curve-fitting methods and often uncovers trends which are not apparent from observed data.

Notizen: This paper estimates the number of workers in the United States who were occupationally exposed to asbestos during and after World War II and assesses the impact of this exposure on overall cancer mortality. The results suggest that over half of the estimated 7–8 million potentially exposed workers employed between 1940 and 1970 may still be alive and at risk of dying from some form of asbestos-related cancer. While the maximum number of excess cancer deaths associated with this occupational exposure is likely to occur sometime in this decade, such deaths will continue to be seen for many years thereafter. At their peak, these deaths may account for an estimated 3% of the annual cancer death toll, with an associated range of 1.4–4.4%.

Notizen: A comparison of the costs and benefits of 57 lifesaving programs reveals striking disparities across agencies and programs in cost/life saved and even greater disparities in cost/life-year saved. Within a broad range the monetary value assigned to the benefits of averting a death usually does not alter the policy implications of the analyses. The findings suggest that despite the substantial disagreements and uncertainties in the theory and practice of valuing lives, careful quantitative analysis can be helpful in setting health, safety, and environmental priorities.

Notizen: Criteria are proposed for both an acceptable upper bound of nuclear power plant risk and a lower bound as a design target. Recognizing that the public risk associated with a power plant can be estimated only by probabilistic analysis of the design features, the spread between the lower design target and the upper bound provides a margin for uncertainty in th probabilistic estimate. The combination of a low probabilistic design target and this margin provides a reasonable expectation that the overall performance will be in the domain of an acceptable risk level. Because the exposure to potential risk is chiefly in the locality of the nuclear station, it is also proposed that compensatory benefits should be provided locally and that these be included as a cost of operation. It is suggested that the upper bound be set at a risk level equivalent to those risks of routine living which are normally accepted, i.e., about 10-4 deaths per year per person (100 deaths/yr/million). The proposed lower design target is 10-8 (0.1 deaths/yr/million), about one-hundredth of the minimal risk from the natural hazards all people are exposed to.

Notizen: The controversy over energy-production risks is in part due to uncertainties and disagreements over the specification of these systems and their characteristics and in part due to the lack of a solid conceptual framework for comparisons between qualitatively different types of risks. The difficulties in specifying energy risks arise primarily from the necessity of using oversimplified descriptions of energy systems and their effects. The major simplifications include the use of marginal analysis (even when inappropriate), the omission of indirect risks, and the incorrect specification of the systems to be analyzed. Comparisons between qualitatively different risks are hampered by the lack of a solid basis for treating occupational risks relative to public risks, catastrophic risks versus chronic risks, and risks distributed differently in time. The difficult problems encountered when social values relating to risk change rapidly lead to delay and indecision. The choice of analytical simplifications and the specification of values systems for energy analysis are best made by considering the context and application of the analysis.

Notizen: We propose a procedure, suitable for regulatory use, for estimating individual and societal risks of carcinogenic materials by using information on interspecies comparisons of carcinogenic potency. The consistent treatment of uncertainties allows evaluation of confidence limits and hence regulatory measures of risk which incorporate safety factors and incentives for better information. Numerical examples are given, together with discussion of the treatment of undetected carcinogens. Applications of the procedure to setting priorities for carcinogenicity testing and to product substitution are mentioned.