ALBERT

Notes: Soils and aquifers can function as effective and economical filter systems for advanced treatment of conventionally treated sewage and other wastewater. The wastewater is applied to the land with low-rate or high-rate infiltration systems. Physical, chemical, and biological processes in the soil improve the quality of the wastewater as it percolates through the vadose zone and into the aquifer to become renovated water. The quality of the renovated water, however, often is not as good as that of the native ground water. To utilize the land for treatment of wastewater, without trading a problem of surface-water pollution for one of ground-water contamination, the spread of renovated water in the aquifer must be restricted. This can be accomplished by locating the system so that the renovated water drains naturally into a stream or other surface water, or by artificially removing renovated water from the aquifer with wells or drains at some distance from the application area. Examples are given of various systems that utilize these principles, and general design criteria are presented. Proper design involves analysis of underground-flow systems for various system geometries. Methods for measuring hydraulic conductivity, particularly in the vadose zone, are briefly reviewed.

Notes: Over the last few years rises in the nitrate content of ground water from wells and springs in the principal aquifers of the United Kingdom have been observed. In a number of cases the concentrations have exceeded the WHO lower recommended limit. In order to determine the reason for the rise, to assess whether it will continue and the eventual nitrate levels, the Water Research Centre has undertaken an extensive programme of drilling and sampling on the Chalk and Bunter Sandstone, and by August 1976, twenty-two sites had been examined. This work has established that high nitrate concentrations (peaks up to 60 mg/l NO3-N have been observed) are present in the unsaturated aquifers at fertilized arable/ley sites. At unfertilized grassland sites nitrate concentrations are low (less than 4 mg/l NO3-N) and below fertilized established grassland values are in the intermediate range. At one farm site near Winchester, models to predict the rate of movement of nitrate through the unsaturated and saturated Chalk have been developed. These suggest that the nitrate levels at this site will remain at an essentially constant value of about 4 mg/l NO3-N until the late 1970's when they will rise progressively to about 4 mg/l NO3-N. The models have been checked against tritium data and the approach is now being extended to other sites.

Notes: The chemical quality of water in many shallow and surficial aquifers exhibits cyclic fluctuations. These fluctuations are caused by the intermittent flushing of contaminants into the ground during recharge events. The contaminants may be natural or reflect man's activities, particularly waste disposal schemes.Over the past 12 years an oil-field brine contaminated aquifer in central Ohio has been monitored. Data from three closely-spaced wells tapping selected parts of the aquifer indicate that brine is flushed into the ground during recharge events and that each contaminated mass maintains much of its integrity as it sinks to the bottom of the aquifer and then migrates laterally to the adjacent river. The most concentrated mass that covers the largest area infiltrates during the spring recharge period, but less concentrated and smaller masses may occur any time rainfall is sufficient to overcome the soil-moisture deficiency.Because of the cyclic nature of recontamination events, care and common sense must be exercised in the extrapolation of quality data, particularly in regard to estimation of contaminant flushing rates.

Notes: A computer program, based on the Hantush inflection method and designed for “desk top” computers is presented. The method assumes a leaky, isotropic, homogeneous aquifer of infinite areal extent. The language employed is BASIC, an interactive language used on the Wang Model 2200 programmable calculator. The program can be easily adapted to FORTRAN IV for use on larger machines.

Notes: A study of the quality of ground water from 250 open wells in the coastal aquifer of Kaniti-Paravada near Visakhapatnam, India brings out the fact that the occurrence of highly brackish waters in certain localized pockets is due to the hydrogeological processes going on in the area and not due to the influence of the sea. The phenomenon is verified by determining standard ratios of tracing sea-water contamination like Ca/Mg, Cl/HCo3’and TA/TH. Conductivity and sodium adsorption ratio are also determined for finding out the alkali hazard, to supplement the observations.

Notes: A hydrochemical study is outlined which demonstrates the mixing of two different ground-water types in the Lincolnshire Limestone aquifer. The two water types consist of a modern recharge water and an ancient possibly connate water. The hydrochemistry of the “interface zone” between the two waters is discussed in detail. In the younger water a relationship between sulphate reduction and bicarbonate is illustrated approaching the “interface zone” and is considered to be related indirectly to the mixing. Carbon isotope content is shown to be radically different in the various ground waters and supports the mixing hypothesis.

Notes: Exact solution to the problem of unsteady drawdown in a leaky artesian aquifer due to a constant discharge nonpenetrating well is presented. Finiteness of the well radius and aquifer anisotropy are considered in formulating the problem. Solution is derived on the assumption that the flux entering the pumped well is uniformly distributed over the plane circular bottom of the well. The aquifer is considered to be finite in thickness, but of infinite lateral extent. The flow of ground water is assumed to be governed by Jacob's model of linear leakage. Laplace transformation technique is employed in the theoretical development. The drawdown function is numerically integrated in terms of dimensionless parameters of the flow system and the results are depicted in graphs.

Notes: The technical feasibility of storing energy in an aquifer is being investigated by Auburn University in a field experiment. Waste hot water from Alabama Power Company's Barry Steam Plant will be pumped into an artesian aquifer, stored, and recovered. The field data will be used by the U.S. Geological Survey to verify numerical models for the analysis of the transport of heat in an artesian aquifer system.

Notes: Environmental effects of feedlot location and related land disposal operations can be minimized if proper knowledge of hazardous conditions are known and appropriate protective steps taken. Common guidelines often do not apply because of differing physical characteristics of local areas.Analyses of various parameters within a soil profile beneath a feedlot revealed none of the chemical constituent present in high concentrations below the 23-foot depth. In areas where shallow ground water was less than 5 feet from the surface, the ground water was found to be affected by the feedlot. Other hazardous areas in feedlot location are flood-prone areas, areas of surface bedrock, and areas of excessive slope.For land disposal operations, loading rates and frequency of application of feedlot waste should be adjusted in accordance with soil permeability, depth to ground water, and irrigation practices to minimize detrimental effects on ground-water quality.

Notes: The successful design and operation of a ground-water monitoring and surveillance system are based on a stepwide process of obtaining hydrogeologic information.Because of the inherent uncertainty and inhomogeneity of natural hydrogeological systems, the true monitoring network cannot be specified before some basic knowledge about system configuration and dynamics is known.Forethought, planning and incorporation of design criteria as part of the initial phase of project management establishes the monitoring network strategy. Optimization of the monitoring network takes place through the completion of the following five phases: (1) preliminary network design and information gathering, (2) initial installation and testing, (3) completion and verification, (4) operational, and (5) project termination.Experience gained from monitoring the conditions at the University of Minnesota's chemical and special waste disposal site resulted in the design and optimization procedure. Concern for possible ground-water contamination led to analysis of surface and subsurface, physical and chemical conditions. Subsequently a monitoring system was established to meet project objectives. No degradation of the ground water was found during the five-year study.

Notes: Dry washes or river beds are often used by southwestern communities to dispose of treated sewage effluent. Because many of these communities rely on ground water as a water supply, there is concern that this disposal practice may contaminate local aquifers. This has led to implementation of monitoring and tracing programs to quantify effluent and ground-water interactions and to development of efficient, easily used predictive models.The treated sewage effluent from the City of Tucson treatment plant has historically been used for irrigation and/or discharged to the normally dry Santa Cruz River. Numerous sampling programs have been undertaken to quantify the chemical quality, temperature, and microbiological activity of the ground water in the area near the Santa Cruz. Ground-water regions with high chloride and nitrate concentrations tend to be associated with areas irrigated with sewage effluent. Quality degradation due to channel recharge is not as evident because the effluent recharge is restricted by fine materials plugging the channel deposits. Recharging water tends to mound near the contact between the Recent and Fort Lowell formations spreading laterally more rapidly than downward.A new tracer, trichlorofluoromethane (trade name Freon 11, C13CF) with applications similar to environmental tritium is being evaluated. C13CF enters the hydro-logic cycle when it is partitioned between the gas and liquid phases during raindrop formation. C13CF in water samples is separated and quantitatively measured by a gas chromatograph with pulsed electron-capture detector.Preliminary Cl3CF analyses of ground water along the Santa Cruz do not correlate with nitrate values because mixing and increasing atmospheric Cl3CF concentrations were not accounted for. However, the presence of CI3CF in the ground water indicates recent recharge. Predictive modeling will be implemented using CI3CF and a finite-state mixing model.

Notes: Large well-field developments in the Mid-Gulf area have caused abnormal lowering of nearby lakes. A map showing the differential head between the surficial aquifer and the underlying limestone Floridan aquifer showed values ranging from 20 feet to zero at a location where the aquiclude is absent. Lake levels had been restored by pumping from limestone wells. From pumping data and analysis of recession limbs, lineal relations between recession rates and differential head appeared to exist. From these, leakance values and vertical permeabilities were determined, with the latter values for two distinctly different sites ranging from 2 × 10-2 to 200 gpd/sf.

Notes: The application of deicing salts is usually a highly successful strategy in improving driving conditions but the environmental impact of such actions may be a cause for concern. Since cheap, harmless and efficient alternatives to salt are not currently available it is suggested that moderation and regulation of salt applications are necessary if harmful side-effects of deicing salts are to be minimized.

Notes: Presented is an analysis of the hydrology and chemistry of the ground water of the Puna District, Hawaii, based on data from 16 drilled wells, ten test wells, two shafts and four exploratory thermal wells. Ground water occurs as (1) perched water located north of Mountain View; (2) dike water located along the east rift zone of Kilauea, and (3) basal water occurring throughout most of the district, except where dike water is present. The east rift zone serves as a barrier to ground-water movement, as demonstrated by the difference in basal water-table levels on the two sides of the rift zone. Salinity and temperature of the basal ground water varies greatly north and south of the rift zone due to differences in precipitation, sea-water intrusion, volcanic activity, flow rates, permeability, and discharge.Basal ground-water type is predominantly sodium chloride. Water samples taken from thermal test well no. 3 showed dissolved silica values two to three times higher than the 49 mg/l average for the rest of the island. Hydrologic and geologic conditions in and around Kilauea's east rift zone support the possibility of accumulations of superheated ground water. The mixing of waters of different composition at depth proved to be the most difficult problem encountered in estimating deep groundwater temperatures.

Notes: A method is presented for selecting ground-water flow paths by comparing modeled and measured hydraulic conductivity distributions. A flow chart is included which shows the steps followed in selecting the concept of groundwater flow which best fits measured hydrogeologic conditions.Both noneffluent and effluent stream conditions are evaluated using the method. Residual maps of hydraulic conductivity are used to show how modeled hydraulic conductivity may be as much as 300 times that expected when the wrong concept is used. Flow nets of modeled and measured data downstream from a flood-water-retarding structure are developed using the selected hydrogeologic conditions.Fitting hydraulic conductivity data results in a distribution of ground-water flow paths which better represent actual flow conditions. The method provides a unique means of calibrating a model in a pilot test area and applying it to geologically similar nearby watersheds. It is also useful for checking paths of subsurface flow where flow distribution is important as it is in the movement of chemical pollutants or nutrients from a source of recharge, such as a watershed impoundment, to downstream waters.

Notes: The value of the electrical resistivity method as a quantitative indicator of ground-water resistivity, porosity and effective matrix resistivity is examined through the equivalence of these parameters as manifested in the surface-measured resistivity of heterogeneous water-saturated sands. It is demonstrated that, where there are unknown variations in porosity, the mapping of groundwater resistivity is most feasible at lower salinities and where porosity is relatively high. Porosity can be determined most exactly at lower values and where groundwater salinity is relatively high. Both these approaches become less efficient as matrix conduction increases. The mapping of effective matrix resistivity is best effected at lower values where this parameter can be approximately monitored against moderate variations in both porosity and ground-water resistivity. In general, however, where there are unknown and pronounced variations in any two of these parameters, the geoelectrical determination of the third can be so ambiguous that the uncertainty in the estimated value of this parameter can exceed the total range of values encountered in an entire formation.

Notes: A classical battle between landowners desiring to protect their fresh ground water from pollution and oil companies needing a disposal zone for injection of oil-field brines developed in Texas County, Oklahoma.Initial studies showed that the disposal zone (Glorieta Formation) was in places only 500 feet below the bottom of the fresh-water aquifer (Ogallala Formation). Furthermore, solution/collapse features in the intervening formations plus numerous poorly plugged wells and exploration holes provided potential avenues of brine migration. The potential for pollution appeared very real. The landowners not only wanted to halt construction of new brine disposal wells, but also wanted all 33 existing disposal wells abandoned and plugged. Tempers flared and intermittent litigation continued for over two years.A more complete hydrogeologic analysis led to the following observations: (a) the potentiometric surface in the Glorieta is 100 to 400 feet below the water table in the Ogallala in areas where brine disposal is taking place; and (b) the transmissivities of the Glorieta and disposal rates are such that even pressure gradients around disposal wells are below the water level in the Ogallala. These hydrologic facts led to the conclusion that, even with a perfectly open conduit connecting the two formations, migration of disposal brine from the Glorieta into the fresh-water Ogallala would be impossible in the critical area because of pressure relationships.Techniques using “pressure bombs” and test injection data are presented by which transmissivity values in the Glorieta were estimated. Disposal well design and completion methods used by the oil companies were found to be inefficient and contributed to operational problems. Specific regulations were adopted regarding disposal wells to further assure that pollution of the Ogallala would not occur.As a result of all parties understanding the hydro-geologic factors, the oil companies are continuing to use the Glorieta as a disposal zone and the fearful landowners are assured that no real pollution hazard exists. This outcome assures full use of all natural resources–which is true conservationism. Ground-water technicians not only have a responsibility to use and protect ground-water resources, but also to assure that unnecessary cost burdens are not placed on other industries in the name of pollution prevention.

Notes: Beginning in February of 1974 and continuing to and through the start-up of the first generating unit at the Jim Bridger Power Plant on August 8, 1974, the authors were drilling monitoring holes, collecting water samples and evaluating water quality and ground-water levels at the project. During the course of this evaluation, considerable data was developed. Some unique and unusual problems were encountered and some of the results are interesting.As of this writing, there are over 25 water quality stations being monitored. Most of these stations are monitoring wells drilled into Tertiary or Cretaceous sedimentary rocks although some monitoring wells are drilled into recent stream alluvium. Also, there are surface-water monitoring sites on two major streams, the freshwater surge pond and the evaporation ponds that receive the blow-down water from the power plants' cooling towers.These waters were analyzed for at least 21 minerals and/or ions as well as pH, dissolved oxygen, turbidity, temperature and such exotics as phenols, hydrazine and ammonia.The indigenous water quality of the area is poor with total dissolved solids ranging to 15,000 mg/l and pH values from 7.3 to 12.3. pH values were found to vary as much as four points between two monitoring stations fifteen feet apart. This water quality is expected to be improved by the importation of relatively high-quality water from the Green River via a 41-mile pipeline.Graphs have been prepared showing some of the concentrations of the more important minerals and their relationship to human, cattle, sheep, crop and boiler tolerances. A water suitability chart also shows how the water quality in the various geologic units as well as the surface water relates to various limitations of water use.Seven of the nine toxic substances cited by the Public Health Service standards were analyzed. Of these, silver, arsenic, cadmium, hexavalent chromium and cyanide were not present in objectionable quantities. Lead, however, was excessive during some months at all well sites and two surface sites on a stream that parallels an interstate highway for more than 6 miles.The water quality was found to have a definite relationship to the geology. Similarly, the geologic conditions are expected to be the governing factor in the rate and direction of flow of subsurface water. This factor will be of major significance when the blow-down water in design concentrations of 30,500 mg/l TDS is discharged into the evaporation pond during the projected thirty-five-year life of the project.

Notes: The abundance and relative purity of ground water guarantees its increase in usage. In some localities, the content of iron and manganese in ground water is so high that these metals must be removed before the water can be used for drinking or industrial purposes.Iron occurs in two states of oxidation in nature–the divalent (ferrous) and trivalent (ferric) forms. The Vyredox method developed in Finland and used now also in Sweden and some other countries oxidizes the ferrous ion, which is soluble in water, to the ferric ion, which is insoluble, before the water enters the well.The Vyredox method achieves a high degree of oxidation in the strata around the well. The method makes use of iron-oxidizing bacteria and aeration wells. A number of aeration wells are placed in a ring around the supply well. Water is forced down the aeration wells but first it is degassed and then enriched with oxygen. The oxygen-rich water provides a suitable habitat for the iron-oxidizing bacteria which assist in the oxidation of ferrous iron. The process must be repeated at specific time intervals to avoid further increases of iron content.The process of precipitating iron in the aquifer has only a slight effect on aquifer permeability. Cloggage of the aquifer surrounding the well should not occur for a period many times longer than the life span of a typical well.

Notes: Data obtained from observation–well programs are used to determine (1) the effect of withdrawals on recharge and natural discharge conditions, (2) the hydraulic characteristics of ground–water systems, and (3) the extent and degree of confinement of aquifers. Wells in these programs can usefully be divided into three networks: (1) a hydrologic network which includes wells needed to determine the extent of aquifers and changes in storage, (2) a water–management network which includes wells needed to determine the effect of withdrawals and hydraulic characteristics, and (3) a baseline network which includes wells needed to determine the response of ground–water systems to natural changes such as those related to climate.

Notes: The drainage basin of Barbadoes Pond, Madbury and Dover, southeastern New Hampshire, was studied by seismic refraction and magnetic measurements as part of an interdisciplinary investigation. The purpose of the geophysical measurements was to provide boundary conditions (bedrock and water–table elevations) for a mathematical model of ground–water flow. The basin is intensively used for recreation, municipal water supply, and sand and gravel mining.Barbadoes Pond is a kettle lake lying in the middle of a broad, flat–topped sand and gravel hill (a “kame plain”). The plain is surrounded by marine clay at a lower elevation.A broad, deep, northwest–southwest trending trough underlies the plain according to seismic refraction measurements (45 lines) and water wells. The present form and location of the trough are attributed to glacial enlargement of a stream valley eroded along a bedrock shear zone. The bedrock topography and seismic velocity are directly related to erosion resistance of the vertically dipping metasedimentary bedrock. Magnetic anomalies are consistent with the seismic results.Water–table elevation correlates with bedrock elevation, not surface elevation. This is a consequence of highly permeable sand and gravel, the principal surfical materials. Apparently the pond is not hydraulically independent of nearby wells and a large reservoir.The results invite speculation that kame plains occur over bedrock troughs. Such a relationship, if generally true, would speed search for good well sites in this region of rapid population growth and industrial development.

Notes: In truly arid regions there is essentially no direct penetration of rainfall. Recharge to ground water is not only infrequent, but extremely localized, occurring only where surface runoff has been channelized or ponded. Over those vast desert areas covered by sparse xerophytic vegetation, the scant rainfall has little or no chance of becoming ground-water recharge. Such water is quickly dissipated by capillarity-assisted evaporation, or through rapid evapotranspiration by short-lived annuals. Where perennial xerophytes cover the ground surface, the extensive shallow root systems quickly utilize all of the rainfall stored in the soil. Beneath the infrequently moistened soil zone is the lower part of the vadose zone, extending to water tables which are usually at depths of tens to hundreds of feet. Almost always these vadose zones have moisture contents well below field capacity.Regardless of the cause, these dry vadose zones are capable of holding additional water, at least up to field capacity. And no water-carried pollutants can reach the water table from the ground surface until a pre-wetted path has been formed for the entire vertical distance. A practical use of this water-holding capacity can be made in the design of wastewater tailings ponds, with predictable safety and with great economic benefit. However, only in predictable geologic conditions, and in limited amounts can the use of this water-holding capacity be recommended. On the other hand, to make no use whatsoever of these great natural dry sponges would be an economic waste.

Notes: Individual subsurface liquid waste disposal has been cited as a source of ground-water contamination. Wastewater treatment systems using emergent marsh vegetation planted in a gravel substrate in a plastic-lined trench could be used to treat septic tank effluent. A pilot plant treating unchlorinated primary municipal effluent achieved the following reductions in mass: BOD5-77%; COD-71%; orthophosphate–35%; total phosphorus–37%; nitrate–22%; coliform bacteria–99.9%. While such treatment is possible only during the growing season, it could be useful at summer cottages, camping areas, resorts and roadside rest areas. Marsh treatment systems are inexpensive to operate and virtually automatic.

Notes: Local ground-water pollution problems are often associated with disposal of sewage from remote recreational areas. Ground water in these areas is routinely used for domestic purposes without treatment. Sewage treatment facilities are often prohibitively expensive. Transporting sewage to municipal sewage treatment facilities is often equally costly, or adequate facilities are not available.A soil incorporation method was tested at two field sites in Michigan's Upper Peninsula to evaluate its impact on ground-water quality; Liquefied campground sewage was injected at 15 cm (6 in.) depths using a liquid manure system. Average dosage levels were 2.7 metric tons per hectare (1.2 ton/acre) of dry sewage solids. The application rate was equivalent to a fertilization rate of 116 kg/ha (104 Ib/a) of total nitrogen. Field tests were conducted on adjacent strips of Kalkaska sand soils in 1973, 1974, and 1975.Changes in ground-water quality in the zone immediately beneath the water table were evaluated by analyzing samples from randomly located wells. Test wells were located directly beneath the treated area and up to 30.5 m (100 ft.) away in the direction of ground-water flow. Nitrate levels in ground water at 3.6 m (12 ft.) depths were higher than control levels from the treated zone to the limit of the test well sampling. Levels of nitrate did not exceed the limits for potable water (10 mg/1 NO3-N). No fecal coliform organisms were detected in ground-water samples. Laboratory tests of the filtration capability of the A and B horizons indicated a high level of filtration of polio virus.Fertilization with sewage increased the biomass of native herbaceous vegetation by 410 percent. Nitrogen content of the treated vegetation was 63 percent above controls. Approximately 48 percent of the added nitrogen fertilizer was incorporated in herbaceous foliage at the end of the first growing season.Site selection guidelines for use by National Forests include remote location of incorporation sites, no potable-water sources within one-half mile downgradient from the site, infiltration rates between 5 and 25 inches per hour, slopes less than 5 percent, and dosage rates which will not exceed 50 kg/ha (56 lb/a) of mineralized nitrogen per year. Injection depths should provide complete soil coverage but sewage should be placed above the B horizon for maximum use of nutrients by plants.The soil incorporation method has been approved for selected sites by the Michigan Department of Natural Resources and the U.S. Environmental Protection Agency, with ground-water monitoring required at each site.

Notes: High concentrations of dissolved nitrate in the ground water in the Redlands, California, vicinity threaten public water supplies. Dissolved nitrate-nitrogen concentrations in water from wells, which frequently exceed 10 mg/1 (milligrams per litre), are attributed to the previous applications of large quantities of commercial nitrogen fertilizer on citrus crops. In a city of Redlands public water-supply well field, wells 1 and 2 normally produce water with dissolved nitrate-nitrogen concentrations of about 18 and 30 mg/1, respectively. Well 1 is a large-capacity well capable of yielding 3,700 gal/min (gallons per minute) [233 1/s (litres per second)] and is the major source of water in the well field.The very permeable unconfined alluvial aquifer is composed of sand, gravel, boulders, and discontinuous clayey deposits. Well 1 is 742 feet (226 metres) deep and is perforated throughout most of the zone of saturation. A major clayey interval from 425 to 480 feet (130 to 146 metres) effectively separates the aquifer into an upper and lower zone. Well 2 is 426 feet (130 metres) deep and is perforated throughout most of the upper zone of saturation. At the well field the static water level (February 1976) was 180 feet (55 metres) below land surface.Independent tests were made on wells 1 and 2 to evaluate aquifer characteristics and to determine the sources of the high-nitrate water. Chemical analyses of water collected from well 1 during the first 48-hour test showed an increase in dissolved nitrate-nitrogen from 4.1 mg/1 to a maximum of almost 20 mg/1. Dissolved nitrate-nitrogen concentrations during the 48-hour test of well 2 stayed constant at 30 mg/1. Interpretation of the chemical data and the results of previous studies indicate that the upper zone of saturation is the higher in concentration of dissolved nitrate.To reduce the concentration of dissolved nitrate in water from well 1, an inflatable packer was placed in the casing at 480 feet (146 metres) to coincide with the bottom of the clayey interval. The packer sealed off the upper part of the well and, as determined from a final test of well 1, reduced dissolved nitrate-nitrogen concentrations from 20 to 4 mg/1 while only reducing well yield from 3,700 to 2,600 gal/min (233 to 164 1/s).

Notes: Book Reveiwed in this articleWATER AND WATER USE TERMINOLOGY, by J. O. Veatch and C. R. HumphreysGROUND WATER STORAGE AND ARTIFICIAL RECHARGE, by the United Nations Department of Economic and Social Affairs, Natural Resources/Water Series No. 2

Notes: A method for collection and analysis of well cuttings samples to aid in ground-water resources evaluation of certain types of alluvial aquifers is described. The method standardizes collection procedures which minimize disruption of the drilling process and allows for easier laboratory interpretation. Analysis techniques for soils are adapted to differentiate between the formations encountered. Wet and dry colors, particle size analysis, acid reaction, plus examination of mineral constituents permits correlation of formation characteristics from wells constructed at different times and by different drillers. An example of the procedure for an area northwest of Tucson, Arizona is given.

Notes: An individual home waste nitrogen and phosphorus removal system was evaluated in the laboratory. The gravity flow system consisted of a 10 × 60 cm (4 × 24 in) vertical Plainfield sand column followed by a series of 8 × 32 cm (3 × 12 in) horizontal columns filled with calcite (CaCO3) or dolomite (Ca MgCO3). Nitrogen removal was attempted using a nitrification-denitrification system where methanol was used as an energy source and P removal was attempted using calcite and dolomite. Separate experiments running from 4 to 6 months were used to test various diameter calcite and dolomite. The phosphorus removal system was also the site of denitrification and hence was in an anaerobic environment. Nitrogen removal was successful with approximately 60–100% removal in a 1-day residence time after methanol addition. Increased denitrification rates were observed using smaller diameter filling materials but no differences were observed between equal-diameter calcite and dolomite. Phosphorus removal was successful initially but after approximately one month, the ability of the calcite or dolomite to sorb phosphorus was curtailed in a 3-day residence time. Results indicated that calcite was superior to dolomite and smaller diameter material was superior to larger diameter in removing phosphorus. However, it appeared that slime growth and organic anion competition covering the sorption sites on the calcite and dolomite prevented significant phosphorus removal after the first 2 to 3 months.

Notes: Ground-water contamination from uranium mining and milling results from the infiltration of mine, mill, and ion-exchange plant effluents containing elevated concentrations of radium, selenium, and nitrate. Available data indicate that radium concentrations in the discharge waters of a producing mine tend to increase substantially as the ore body is developed. Whereas natural background radium concentrations are generally about several picocuries/liter (pCi/l), 100 to 150 pCi/l appear in the effluents of operating mines. The discharge of such highly contaminated mine effluents to streams and seepage from tailings ponds, creates a long-lived source of ground-water contamination. Seepage of mill tailings at two active mills ranges from 126,000 to 491,000 m3/yr and, to date, has contributed an estimated 2400 Curies of uranium, radium, and thorium to the ground-water reservoir. The shallow aquifer in use and downgradient from another mill has been grossly contaminated with selenium, attributable to excessive seepage from a nearby tailings pond.Radium, selenium, nitrate and, to a lesser extent, uranium, are of most value as indicators of ground-water contamination. Gross alpha results are not consistent indicators of radium or uranium in water, although uranium does appear to be the principal contributor of alpha activity. Accurate radium-s226 analyses yield the most information for radiological evaluation of drinking water.To date, no adverse impacts on municipal groundwater supplies have been observed. However, industry-sponsored environmental monitoring programs are inadequately designed and implemented, and may not define the full, long-term impact of mining and milling operations on the ground-water quality of the study area.

Notes: Step-drawdown tests of a well in a dolomite aquifer in north-central Ohio, before and after it was enlarged from 10 to 12 inches (250 to 300 millimetres) in diameter, indicate changes in the well-loss constant, the exponent for turbulent flow, and the formation loss factor. The calculated difference in drawdown resulting from enlarging the well is of little practical importance at rates of 300 to 500 gallons per minute (19 to 31 litres per second), the range of rates at which the well is expected to be pumped, but for higher rates the decrease in drawdown and consequent reduction in power costs could be significant. For a pumping rate of 1,500 gallons per minute (95 litres per second), the decrease in drawdown would be 20.4 feet (6.2 metres).

Notes: Information from 675 water wells in and around Phelps County, Missouri shows that discrete areas of differing ground-water quality can be identified and mapped. The best quality ground water, as judged by its low nitrate content and coliform bacteria density, is found in areas of relatively little agricultural (pasture and livestock) land use. The poorest quality is found in areas of intensely developed karst and greater agricultural land use. The adverse effect of agricultural land use on ground-water quality is more severe in the intensely developed karst than in the less intensely developed. Rural population density and soil association variations have no readily discernible effects on ground-water quality. Nitrate content varies seasonally and in response to rainfall, and decreases with increasing well depth. Coliform bacteria density is positively correlated with nitrate content.

Notes: Fuel oil, underlying approximately four acres, was discovered floating on the water table beneath oil products' storage tanks. The oil, of unknown origin, originally was observed discharging to a river adjacent to the storage tank area from an abandoned clay tile. Approximately 35,000 gallons (132,500 liters) of oil were intercepted and contained prior to the field investigation by borings.Hantush's (1968) theory for the formation of a fresh-water lens in an unconfined saline aquifer was used to examine the decay of an oil lens resulting from a catastrophic oil spill at the site. The theory indicated that too much time had elapsed from the first detection of oil at the surface to the collection of subsurface information to make it feasible to speculate on the precise nature of the spill event–catastrophic or a slow leak. Application of the theory and consideration of the ground-water hydrology of the site did make it possible to identify the probable source area of the spill. Analysis of the flow system also assisted in the selection of the appropriate collection system to clean-up the spill.Subsequent to the boring program, an electrical resistivity survey was conducted to test the feasibility of delineating the extent of the subsurface oil by this method. Only modest success was achieved, apparently because of the thinness of the oil-bearing zone.

Notes: Because of increasingly stringent laws governing discharge of fluid wastes to surface waters, the alternative of discharge to the subsurface has become attractive. The physical-chemical processes that prevail in the subsurface are not well understood, but they are clearly not identical to processes of purification in surface waters. For example, in the subsurface the process of oxidation may be of little value in significantly reducing the concentration of discharged contaminants; in contrast, oxidation plays an important role in purifying surface waters. Eleven physical-chemical processes can be identified as having potential value for purifying wastes discharged to the subsurface, as follow: dilution, buffering of pH, precipitation by reaction, hydrolysis, oxidation or reduction, filtration, volatilization, biological assimilation, radioactive decay, membrane filtration, and sorption.Discharge to the vadose zone may be a safe means of disposal of wastes in arid regions. But it is necessary to carefully test the suitability of a particular site for a particular waste. Processes of purification in the vadose zone can be incorporated into a workable plan of discharge if adequate studies and safeguards are employed. Regulations governing subsurface discharge should take into account the physical-chemical processes that may act to purify the waste fluids. In one set of experiments, a soil from Sulfur Springs, New Mexico was capable of removing large quantities of dissolved molybdenum and copper from a synthetic mill water, and the soil was able to quantitatively retain the copper during subsequent leaching by fresh and metal-free mill waters. Such studies permit rational plans of discharge to be developed.

Notes: In 1973, the Suffolk County Department of Environmental Control in cooperation with Cornell University began a study on nitrogen (N) fertilization of potatoes and turfgrasses. The research and demonstration project has shown that current practices result in substantial N losses; and, in many cases, excessive use of N reduces crop yields and turf quality. Annual N losses of 50 lbs. per acre (55.5 kg-N/ha) are sufficient to cause a concentration in the aquifer's surface layer of 10 mg/1 nitrate-N (New York State Drinking Water Standard).The eastern portion of Long Island supports a productive agricultural industry whose main crop is potatoes. Ground-water surveys have shown that the aquifer system of this area is contaminated with nitrate nitrogen. The average potato grower applies 200 to 250 lb-N/a (222 to 278 kg-N/ha) at planting time; and depending upon a number of factors, N recovered in harvested tubers varies from 75 to 150 lb-N/a (83 to 167 kg-N/ha). Losses to the ground water could vary from 50 to 175 lb-N/a (55.5 to 194 kg-N/ha). The study has shown that the application of 150 lb-N/a (167 kg-N/ha) can still maintain maximum potato yields and keep the N loss to ground water below 50 lb-N/a (55.5 kg-N/ha) by improving nitrogen-use efficiency. This is done through splitting N applications so that one-third to one-half is applied at planting and the remainder is applied prior to the period of rapid crop growth and nutrient uptake. On-farm demonstration plots are being used to convince growers to reduce N rates and adopt more efficient application methods.The western portions of Long Island are highly urbanized and turfgrasses may be fertilized at rates up to 350 lb-N/a (389 kg-N/ha). Potential leaching losses are high for turfgrass as N is not recovered in harvested plant materials. Experiments are underway to establish rates of biomass N buildup under several fertilization regimes. Preliminary results indicate that N-use efficiency increases with more frequent but smaller N applications. Encouraging the use of low maintenance turf species appears to be the best long-term solution.

Notes: A preexisting network of 124 wells used for fire protection in the Town of Southampton, Long Island, New York, was monitored during a one-year period for groundwater levels and chloride concentrations. Water from 26 wells had chloride concentrations of 50 mg/l or greater and in 17 wells the chloride concentration exceeded 200 mg/l. Most of these wells are located in two densely populated areas. The possibility of widespread intrusion in one of these areas has not been previously documented. In addition, detailed water-table contour maps are presented for selected areas within the Town.

Notes: Lake rejuvenation efforts in the Upper Midwest are important to the area's economic dependence on high-quality lakes for tourism. In developing eutrophication studies for lakes in this area, it is essential to determine the thickness of aquifer communicating with the lake, as a preliminary to calculation of the lake flushing rate. The thickness of communicating aquifer is particularly critical for lakes fed primarily by ground-water recharge, e.g. Snake Lake, Wisconsin. Through use of observation wells and chloride tracer analysis, effective aquifer thickness at Snake Lake is determined to be 30 to 50 feet. However, the local flow systems are additionally found to be highly variable through the progression of seasons. The possible effect of such dynamic seasonal fluctuations on the local flow system should be considered in eutrophication studies to avoid possible improper siting of underground chemical and/or petroleum storage facilities and septic tanks in glacial deposit environments.

Notes: Chemical analyses of major dissolved constituents in approximately 300 samples of ground water and 60 samples of stream water indicate that the process of ion filtration may control the distribution of some major ionic species in the water of the Saginaw aquifer system. This system, which is in the upper Grand River basin of the central part of the southern peninsula of Michigan, consists of sandstone, shale, coal, and limestone of the Saginaw Formation of Pennsylvanian age and overlying glacially deposited sand and clay of late Wisconsin age.The Saginaw Formation is recharged through the glacially deposited material; however, the concentrations of iron, calcium, sulfate, and chloride are greater in water in the glacial deposits than in water in the underlying Saginaw Formation. It is hypothesized that shale beds in the Saginaw Formation act as ionic filters, allowing water with a lower dissolved-solids concentration to move through the shale to the sandstone aquifer. A concentration of ions greater than input value forms above the shale beds. Gravity provides the energy necessary to filter the water in a process of reverse osmosis. The similarity of this hydro-geologic system to other systems suggests that ion filtration may occur in many potable-water aquifers.

Notes: Geothermal energy–the naturally occurring heat of the earth's crust–has been used since earliest time by man for a variety of purposes. In recent times, wells have been drilled in close proximity to surface indicators of geothermal heat in an attempt to utilize this resource. The steam or hot water obtained from these wells has been used for agricultural and recreational purposes, to heat buildings, and to generate electricity. It has been estimated that by the year 2,000 between 30,000 Mw and 395,000 Mw of electricity can be generated in the United States with naturally occurring steam.Most geothermal systems of the world are located either in volcanic districts or at the margins of continental plates above subduction zones or spreading ridges. In addition, large quantities of heated ground water under pressure are found throughout the world in many large artesian basins.The various geothermal systems of the world can be divided into three major types based on the occurrence of associated ground waters: hydrothermal, geopressured and hot dry rock masses. In a hydrothermal system most of the heat energy is transferred by convective circulation of ground water and/or steam. Hydrothermal systems can be divided into three general types: vapor dominated, in which only dry steam is produced; wet steam, in which steam and hot water are produced; and hot-water systems in which only hot water is produced.In the United States the most optimum location for the existence of a commercial geothermal deposit is either in the Gulf of Mexico artesian basin or in the mountainous States of the West where hydrothermal systems are found.At present, and probably for years to come, the primary geothermal exploration efforts will be aimed at discovering and developing high-temperature hydrothermal systems to be used for generation of electricity. Typical problems that will be encountered in the exploration and development of such systems are: (1) Defining the type of hydrothermal system under investigation; (2) ground-water flow direction, whether it is vertical or horizontal; (3) recharge rates and areas; (4) porosity and permeability determination; (5) water needs and consumptive usage; (6) disposal of waste fluids; and (7) legal and institutional considerations. A discussion of each problem area is presented. In order to solve many of these problems at the outset, it is believed that the geohydrologist should be an essential member of the exploration team.

Notes: At the Hagman Road Landfill refuse is buried in lacustrine and glacial till deposits consisting mainly of silty clays. These clays overlie a thick carbonate aquifer used locally for water supply. The dominant direction of ground-water flow is vertically down. Time of groundwater travel from the refuse to the aquifer is estimated at 12 years, putting first arrivals in 1978. Water quality monitoring of bedrock waters shows decreases in total dissolved solids, sulfates, calcium, magnesium, chlorides, and total hardness with increases in alkalinity to exist locally beneath the landfill. The principal chemical reaction felt to explain some, but not all of the water quality changes is sulfate reduction. Theoretical geochemical modellings help to support this interpretation. The landfill is hypothesized to have either triggered or accelerated sulfate reduction by creating the reducing environment.

Notes: A resistivity survey was made in the vicinity of a landfill in a glacial aquifer to determine the extent of ground-water contamination. The survey consisted of 12 electrical soundings with the Winner probe configuration. An examination of the sounding curves and logs of nearby test borings suggested a three-layer geoelectric model for studying water quality variations.The thicknesses and the resistivities of the upper two layers were fixed. Differences in apparent resistivity were assumed to be due only to differences in specific conductance of ground water in the saturated zone (third-layer resistivities). Apparent resistivities at the largest probe spacing, 102 feet (31 m), were then computed for a range of assumed third-layer resistivities. Specific conductances corresponding to third-layer resistivities were then computed using an assumed formation factor of 4.5. A relation between apparent resistivity at the 102-foot spacing and specific conductance was developed for converting apparent resistivities to specific conductances. Quadratic trend surfaces developed for specific conductances measured at monitoring wells and computed from apparent resistivity are shown to be in good agreement.Under favorable conditions, interpretation of electrical sounding curves provides a basis for estimating specific conductance of ground water from surface resistivity methods. This leads to a quantitative assessment of ground-water contamination which compares favorably with that determined from monitoring wells.

Notes: The sharpness of the end point during the titration for magnesium or calcium using the EDTA titrimetric method is improved by using the free acid form of CI Mordant Black 11 buffered to pH 10 with ammonium hydroxide rather than its sodium salt. Apparently, the ammonium salt of the dye sorbs more strongly in the blue region than does the corresponding sodium salt increasing the end point resolution; hence use of the free acid rather than the commercially available sodium salt is suggested as the end point indicator. Methods for converting the commercial dye to the free acid are given.

Notes: The introduction of an infiltration mechanism called rapid recharge assists in the mathematical modelling of large seasonal variations in the response of the confined portion of a limestone aquifer. Such modelling employs the technique of using an interactive analogue-digital computer, together with a new method of utilising standard hydrological input data.

Notes: An electrical analog model of a small northern peat bog and its watershed was constructed from available hydrologic and geologic data. Initial experimentation involving comparison of modeling results with historical data resulted in modification of model construction. Modeling results are successful in supplying information on the hydrologic interaction of the bog with the surrounding region. Significant among these findings is the fact that the bog exerts no stabilizing effect on regional hydrology. The bog rather magnifies seasonal variations through rapid surface discharge during wet periods and removes water through evapotranspiration during dry intervals.

Notes: Any improperly constructed or inadequately destroyed water well can endanger ground-water quality by providing a path for pollutants to reach usable water. Another kind of well, the cathodic protection well, can also present a hazard to ground water.Cathodic protection wells house devices used to alleviate electrolytic corrosion of pipelines, tanks, and other installations situated in a corrosive environment. They are widely used in the petroleum and gas industry. Cathodic protection is a technique used to prevent or minimize this corrosive action by redirecting the current to a substitute anode which then deteriorates instead of the pipeline. To offset the disadvantages of horizontal, or shallow vertical, anodes, and since almost all ground water has enough salt to conduct electricity, the vertical deep anode (cathodic protection well) was developed. They normally range from 100 to 500 feet in depth and 8 to 10 inches in diameter.To prevent cathodic protection wells from acting as conveyances for pollutants, they must be properly designed and constructed at the outset and, when their useful lives are over, properly destroyed. This is best done by following standards of good practice. California has developed and is implementing such standards as part of its program for ground-water basin protection.

Notes: Increasing concern over ground-water pollution from hydrocarbons is being expressed by governments and industries in western Canada. The Manitoba government has recently held public hearings on the subject and is now working with the petroleum industry to develop new legislation concerning the handling of refined petroleum products. The petroleum industry has developed a series of “oil spill manuals” which describe procedures for controlling leaks and spills of petroleum products. Emphasis is now being placed on education and prevention, and hydro-geologists are involved in developing training manuals and films.

Notes: In areas where the bedrock is irregular, depressions in the bedrock formation can yield significantly higher amounts of water because the aquifer has a greater saturated thickness. Finding these areas by drilling test holes is a common practice but one that can be conducted more economically if an efficient search procedure is utilized. This paper describes such a technique called the Fibonacci Search and shows that it can save thousands of dollars in the cost of drilling test holes when compared to “brute-force” methods.

Notes: An analytical solution obtained for unsteady flow to a cavity well has been simplified for finding the aquifer characteristics, i.e. coefficient of storage and transmissivity. In the analysis presented here the relationships become fairly simple for the close approximation of the unsteady state solution.