ALBERT

Notes: 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.

Notes: 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.

Notes: 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).

Notes: 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.

Notes: 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.

Notes: 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.

Notes: 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.

Notes: 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.

Notes: 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.

Notes: 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.

Notes: 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.

Notes: 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.

Notes: 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.

Notes: 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.

Notes: 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.

Notes: 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.

Notes: 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.

Notes: 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.

Notes: 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.

Notes: 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.

Notes: 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%.

Notes: 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.

Notes: 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.

Notes: 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.

Notes: 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.

Notes: This paper presents a survey and comparative evaluation of methods which have been developed for the determination of uncertainties in accident consequences and probabilities, for use in probabilistic risk assessment. The methods considered are: analytic techniques, Monte Carlo simulation, response surface approaches, differential sensitivity techniques, and evaluation of classical statistical confidence bounds. It is concluded that only the response surface and differential sensitivity approaches are sufficiently general and flexible for use as overall methods of uncertainty analysis in probabilistic risk assessment. The other methods considered, however, are very useful in particular problems.

Notes: This study analyzes the risk involved in the chlorine industry in North America. A hypothetical chlorine plant with diaphragm electrolytic cells and a chlorine production of 300,000 metric tons per year was studied. Risk in terms of man-days lost per year was evaluated for nine stages in the manufacture and distribution of chlorine. The highest risk was found to be “Maintenance of the Chlorine Plant” (37.6% of total man-days lost per year). “Raw Material Acquisition for Materials in Chlorine Plant” (1.3%) and “Storage of Chlorine at Chlorine Plant” (0.3%) both had very little risk. “Transport of Chlorine to User by Rail, Pipeline, Barge, and Truck Combined” also gave relatively low risk (10.2%), an important result since this risk is involuntary and is the category that usually causes the most concern. The kind of risk evaluation presented here, while relatively new, should be helpful in identifying those areas in industry on which time and money can be spent with maximum benefit to reduce risk.

Notes: U.S. Government agencies have adopted a linear-no-threshold dose-response relationship for chemical carcinogens, and have set up a Carcinogen Assessment Group (CAG) to determine the proportionality constants in these relationships. Their results are summarized for the carcinogenic elements Be, Cr, Ni, As, and Cd. It is shown that when effects are integrated over ∼105 years, an atom of these elements in the ground has a reasonable chance (10-4-10-1)of being ingested orally by a human. From this it is shown that, over this time period, producing electricity by coal burning causes 320 fatalities/GWe-yr and all coal burning in the United States causes 74,000 fatalities/year. Commercial use of these carcinogenic elements causes the following numbers of fatalities/yr: Be–900, Cr–87,000, Ni–10,000, As–62,000, and Cd–230,000. Use of CdS and GaAs photovoltaics would cause 2200 and 66 fatalities/GWe-yr, respectively, and production of construction materials for photovoltaic arrays would cause 11 fatalities/GWe-yr through use of coal. The calculational methods are derived from those used in risk assessments of radioactive wastes, and their questionable aspects apply equally to those assessments. It is shown that, contrary to present beliefs, it is much safer to dump these elements into rivers than to bury them in the ground, and by far the safest procedure is to dump them in the oceans.

Notes: This study examined what lay people mean when they judge the “risk” of activities that involve the potential for accidental fatalities (e.g., hang gliding, living near a nuclear reactor). A sample of German and American students rated the “overall risk” of 14 such activities and provided 3 fatality estimates: the number of fatalities in an “average year,” the individual yearly fatality probability (or odds), and the number of fatalities in a “disastrous accident.” Subjects' fatality estimates were reasonably accurate and only moderately influenced by attitudes towards nuclear energy. Individual fatality probability correlated most highly with intuitive risk ratings. Disaster estimates correlated positively with risk ratings for those activities that had a low fatality probability and a relatively high disaster potential. Annual average fatality rates did not correlate with risk ratings at all. These findings were interpreted in terms of a two-dimensional cognitive structure. Subjective notions of risk were determined primarily by the personal chance of death; for some activities, “disaster potential” played a secondary role in shaping risk perception.

Notes: Drawing on the literature from the fields of cognitive and social psychology, sociology, and political science, we discuss perceptions of risks and benefits, the impact of perceptions and personal preferences on choice and behavior, the question of “socially acceptable” thresholds of risk, and the analytic and descriptive means by which such thresholds might be identified. We hypothesize that existing psychometric methods may be adapted for the scaling of perceived benefit. We review factors hampering the application of formal methodologies in the resolution of controversial public debates, and express doubt about the identification of a socially acceptable threshold of risk. We argue that the emphasis of research in this field should be shifted toward explicating the use of risk and benefit perceptions in the process of personal decision-making. Finally, we suggest several social science research approaches that may be used to address these issues.

Notes: A quantitative definition of risk is suggested in terms of the idea of a “set of triplets”. The definition is extended to include uncertainty and completeness, and the use of Bayes' theorem is described in this connection. The definition is used to discuss the notions of “relative risk”, “relativity of risk”, and “acceptability of risk”.

Notes: Records of nonoccurrence of catastrophic accidents from technologically based industrial operations, such as nuclear power generation and liquefied natural gas (LNG) transportation are sometimes cited as evidence of the safety of such operations. The appropriateness and inappropriateness of different types of models of accident processes for these systems are discussed. Selectivity biases in defining both die numerator and denominator for accident rates are shown to be important to the size of the estimated rate and these are illustrated by examples. Inferential approaches to estimating a rate based on zero occurrences are briefly discussed. The conclusion reached is that a record of zero occurrences is of cold comfort in ruling out catastrophic events. Experience, unless it is interpreted by strong models and assumptions, helps little to establish very small probabilities of a catastrophe.

Notes: The basic characteristics of determining acceptable risk are discussed. Technical, political, and social aspects of the problem add much complexity. The appropriate manner to reach responsible decisions regarding acceptable risk is suggested. This explicitly addresses the alternatives, the objectives, the uncertainty, and the values which constitute the information necessary to arrive at any solution. The inappropriateness of many “solutions” currently in use or “suggested” is exposed.

Notes: Response or “slug” tests to determine the hydraulic conductivity of in situ earth materials are often difficult to perform in situations of very high hydraulic conductivity. In small-diameter standpipes, rapid response to the induced head difference, often in a matter of seconds, is difficult to measure with conventional well sounders. Instantaneous induction of a known head difference is also a major problem when dealing with very fast response times. A method of performing such tests has been developed, utilizing electronic pressure transducers to monitor the response to a pneumatically induced head. Increased air pressure within the standpipe causes displacement of the water column to accommodate the air pressure. Once the aquifer has re-equilibrated in this condition, sudden release of the air pressure constitutes an instantaneously induced head difference. The response measured by the electronic pressure transducer can be recorded digitally or by an analog chart recorder with fast paper speed. This method has been used to measure basic time lags in the order of several seconds. The use of electronic pressure transducers and pneumatically induced head differences will allow accurate measurements in situations of higher hydraulic conductivity than would be possible using common response testing techniques.

Notes: A method of researching data at a mine to determine the environmental and economic impact to the operator has been developed. This method consists of developing geologic, hydrologic, and geochemical maps that can be used to provide a three-dimensional view of the subsurface environment before, during, and after mining.The following maps were developed: a standard topographic base map, structure contour maps, static water level maps, and several iso-concentration maps for pH, iron, manganese, sulfate, and specific conductance. Where possible geologic-hydrologic cross sections were drawn to aid in the environmental interpretations. It is possible to use the data to develop the best possible mining plan for a geologic region which considers geographic, technical, economic, and environmental parameters. The iso-concentration maps for a proposed surface mine site can be used to define the extent of concentration fields, point source locations, and concentration gradients.To demonstrate the use and interpretations of the data provided by this method, the results of two mine site case studies are presented that will discuss: (1) Dewatering problems; (2) Mining recharge areas; (3) Mining coal overlain by an acid overburden; and (4) The impact of prior surface mining.

Notes: High Radon-222 (222Rn) concentrations exist in ground water from most granitic rocks in Maine. Some values exceed the suggested limit of 500 pCi/1 (E.P.A., 1976) by more than 100 times. Although high values (x̄= 22,100 pCi/1) are conclusively linked with the granites, high values are also present in ground water in metasedimentary rocks from sillimanite- (x̄= 13,630 pCi/1) and sillimanite-orthoclase zone metamorphic terrains. Metamorphic (anatectic) pegmatites with hydrothermally introduced uranium are thought to be the source of radon in high grade terrain. At lower grade (chlorite to staurolite), no relationship exists between 222Rn content and metamorphic grade, although each rock formation has a somewhat characteristic 222Rn range from ground water, ranges which overlap. Considerable local 222Rn variations exist within the same rock body, reflecting local geologic and hydrologic conditions. Data on well depth, type of well, well yield, overburden type and thickness, and water chemistry show that 222Rn may increase slightly with well depth up to 50 to 75 m and is essentially constant thereafter. Low yield wells, generally associated with areas of thin overburden, tend to have higher 222Rn values than high yield wells, normally associated with thick sand and gravel overburdens. 222Rn concentrations decrease with increasing sodium concentrations, suggesting that low 222Rn wells are closely linked with surface waters. No other chemical parameter (Na, K, Ca, Mg, Fe, Mn, Zn, and Cu) correlates with 222Rn content within a single rock unit.

Notes: During the past decade, increasing concern has arisen over the potential contamination to ground-water systems by chemical substances which could threaten human health or the environment. Assessment of the impact of toxic substances on ground-water quality is only as good as the chemical data analyzed in ground-water samples.Small-diameter observation wells can be evacuated rapidly by an air-driven pump. This air-driven system has proven very effective when depth to water surface distances are greater than the suction lift height. The use of this device has greatly reduced well evacuation time in comparison to the conventional bailer. Following evacuation of several well volumes, an all-teflon bailer can be used to collect the water sample for analysis. This material can be machined with some difficulty, but its inert properties render it a most desirable material for this purpose. Both of the devices discussed herein may be improved upon to fit different-sized wells or different situations. The materials are easily accessible and except for machining of the teflon bailer parts, can be constructed with minimal effort. These devices were designed by Keith Bandt and Dan Buss of Camp Dresser & McKee, Inc., and used by the authors on various ground-water monitoring projects to meet collection standards dictated by the U.S. EPA (1977) and the Wisconsin Department of Natural Resources (WDNR, 1977).

Notes: This paper presents a systematic method for approximating hydraulic head gradients from randomly located hydraulic head values. The locations of these head values are connected by straight lines to form a network of triangles. Over each triangle, a plane surface is used to approximate the head values; the gradient of this plane is then taken as the hydraulic gradient. Given values of porosity and hydraulic conductivity, the fluid velocity can be calculated from Darcy's Law.

Notes: In considering reversible sorption processes in ground-water flow systems, it is important to determine whether the ground water is in steady-state or dynamic chemical evolution. In steady-state chemical evolution, the sorbed site populations at any point along the flow path are in equilibrium with the way in which ground water will evolve chemically due to mineral dissolution/precipitation, redox reactions, etc., during flow when it reaches this point. In dynamic chemical evolution it is not. In the steady-state case, a location in the flow system can be characterized by a constant distribution coefficient over time for an ionic species involved in reversible sorption reactions. In the dynamic case, the distribution coefficient can be expected to vary at a location in a flow system over time. Subsurface contaminant migration problems which confront hydrogeologists invariably are of the dynamic chemical evolution type and the notion of a constant distribution coefficient or Kd to describe reversible sorption processes cannot be entertained.

Notes: The proper collection of ground-water samples for analysis of organic compounds differs substantially from routine inorganic constituents because the former are easily contaminated and generally appear in the parts per billion range.Much of the sampling equipment that has been developed at the Robert S. Kerr Environmental Research Laboratory during the past few years is constructed from Teflon or glass. While the former is expensive and the latter is fragile, neither contaminate or modify a water sample as does rubber, metal and most plastics.Designs are provided for a grab sampler, a continuous sampler consisting of adsorbent columns, a protective housing for a sampling system, a continuous discharge/high lift glass pump, and a system for obtaining highly volatile organic compounds from the unsaturated zone.

Notes: The Cambrian-Ordovician aquifer (deep sandstone aquifer) of northeastern Illinois and southeastern Wisconsin consists of a number of hydraulically connected sandstone and dolomite units. The aquifer dips gently to the east beneath Lake Michigan and is regionally confined by the Maquoketa shale, which has been thinned and removed by erosion to the west. Recharge to the regional aquifer system occurs where the shale is missing and to a lesser extent across the shale wherever there are downward hydraulic gradients. The practical sustained yield from the aquifer is 46 million gallons per day (mgd) (170,000 m3/day) in Illinois and approximately 34 mgd (129,000 m3/day) in Wisconsin. In 1978, pumpage from the aquifer amounted to 142 mgd (537,000 m3/day) in the eight counties of northeastern Illinois compared with an estimated 38 mgd (144,000 m3/day) in Wisconsin. Pumpage in Illinois has exceeded the practical sustained yield every year since 1958 while in Wisconsin the practical sustained yield was reached about 1975. Two regional pumping cones have developed. One centered in the Chicago region has maximum drawdowns of more than 900 feet (275 m) while in the Milwaukee pumping cone water levels have fallen about 350 feet (106 m). The greater drawdown in the Chicago pumping cone has changed the regional hydraulic gradient and 9.3 mgd (35,200 m3/day) of ground water is now being drained from beneath Wisconsin into Illinois. A digital computer model of the aquifer system was used to separate the amount of total drawdown in the aquifer attributable to each pumping center as well as to predict future ground-water levels. At the Illinois-Wisconsin border in 1973, there was 265 feet (81 m) of drawdown of which 94 feet (28 m) were due to pumpage in Wisconsin and 171 feet (52 m) due to pumpage in Illinois. Allocations of Lake Michigan water to ground-water users in Illinois could result in a reduction of pumpage to less than 46 mgd (174,000 m3/day) by 1985. In order to obtain a modification of the U.S. Supreme Court decree permitting Illinois to divert 3,200 cubic feet per second (cfs) (7,829,000 m3/day) of water from Lake Michigan, Illinois must agree that future allocations of Lake Michigan water will be done in such a manner as to reduce Cambrian-Ordovocian aquifer pumpage. The rate of ground-water decline will decrease substantially if this occurs. Water resources managers in southeastern Wisconsin should limit pumpage from the deep sandstone aquifer to approximately the current rate.

Notes: Considerable changes in water quality have been observed in ground water pumped from wells in quaternary formations in Poland. These changes include increases in dissolved calcium, sulfate, iron and manganese.Experimental results indicate that dissolved-solids' increases are influenced by the introduction of oxygen into the hydrogeochemical environment during pumping.The oxidation of sulfur compounds produces acid, which increases the solubility of numerous chemical compounds. Bacterial catalysis of some reactions is indicated.

Notes: A four-year case study evaluation of the ground-water availability in a small multiaquifer basin in northern Delaware has been performed to determine the hydrologic conditions when pumpage approaches the expected long-term basin-wide rate of ground-water recharge. The basin is located in the Piedmont physiographic province and includes rocks of the Cockeysville marble and Wissahickon schist.Only about one-third of the basin (the marble area) contains favorable geologic conditions for large production well development (∼ 1 MGD/well); however, the entire basin serves as a recharge area for the marble sector. The manageable storage area is limited to the marble area; consequently, accurate ground-water recharge and storage characteristics of this basin are critical to maximizing the long-term yield while minimizing adverse impacts of pumpage. The analysis was performed using the Thornthwaite-Mather water balance accounting procedure to determine the long-term significance of the exported pumpage.

Notes: Data loggers, in combination with appropriate electronic measuring devices, can improve pumping-test data by reducing cost and by increasing accuracy, precision, speed, and computational convenience. The data logger (digital recorder) described herein was tested and found to work well. Sensitivity to blowing sand and freezing temperatures, excessive power consumption, and poor display legibility in bright sunlight are minor design deficiencies that slightly restrict the usefulness of this data logger. These problems can be easily corrected.

Notes: If past ground-water movement in the vicinity of contamination could be shown pictorially, determination of the extent of contamination would be facilitated significantly. Furthermore, if pictorial representation of future ground-water movement under presumed conditions reflecting alternative plans of contaminant removal or containment could be provided rapidly, an effective plan could be developed speedily and thus economically. A flow path and arrival time plot, which is developed through the use of a flow system kinematics mathematical model, provides such visualization of ground-water movement. Contrary to the popular notion that the kinematics model requires much more geohydrologic datathan the finite difference or element models, it was found that meaningful kinematics models could be developed based on relatively limited data. Presented in this paper are: a brief description of the development of flow path and arrival time plots, information obtainable from such plots, an example of the use of the plots in determining the extent of contamination of ground water, and an example of the use of the plots in formulating a contaminant removal plan.