ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1978.tb03250.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTThe hypothesis that present‐day ground‐water gradients in arid regional sedimentary basins are a decay feature of very old recharge mounds is examined using a resistance network analogue. A longitudinal section model of a conceptual basin with some specific control of aquifer permeability and ground‐water age is used.With reasonable combination of aquifer permeability and specific yield it is shown that an acceptable head decay could have occurred over the past 10,000 years to produce the present‐day gradient. In the model adopted, decreasing permeability with depth was found to be required to accord with14C ground‐water age data.Although the model is not considered to be definitive for any particular aquifer the results show that fossil gradient conditions could exist in the regional basins for long periods and should be taken account of in ground‐water resources

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1978.tb03251.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTSeismic refraction methods can often indicate the saturated thickness of an aquifer. However, if an impermeable blind zone layer is present, it will not show up in the refraction profile. As a result, saturated thickness and transmissivity values indicated by the profile will be too high. It is thus important in many cases to look for a blind zone layer, and resistivity data combined with geological considerations are two possible ways of inferring its presence.

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1978.tb03252.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTField and laboratory tests were made using suspensions of baker's yeast (Saccharomyces cerevisiae) to trace movement of microbes in artificially recharged ground water. Yeast cells penetrated more than 7 meters into a sand and gravel aquifer in less than 48 hours. It is believed that most of the cells travelled through channels formed by the solution of calcium carbonate rather than through intergranular pores. Ease and sensitivity of detection, coupled with negligible background correction, suggest that baker's yeast is an excellent choice as a tracer for this type of application.

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1978.tb03253.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTNitrogen‐isotope values (δN15) of ground‐water nitrate on Long Island, New York, correlate with δN15ranges of nitrate sources which contribute to the ground‐water systems. The δN15of nitrate in water from the upper glacial aquifer, the water‐table aquifer on Long Island, shows a shift from lighter values in the eastern part of the island where land is used predominantly for agriculture, to heavier values toward New York City where land is used for suburban residences with septic systems or sewers. δN15values for inorganic fertilizer, unfertilized cultivated fields, and animal wastes show a similar shift from low to high values: −3 ‰ to +2 ‰+ 2 ‰ to + 8 ‰ and +10 ‰ to +20 ‰, respectively.Nitrogen‐isotope ratios of nitrate in water from the deeper Magothy aquifer indicat

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1978.tb03254.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTSand‐box and Hele‐Shaw models were used to study waste water injection into two‐phase ground‐water bodies. Two types of experiments were conducted: “static” experiments in which there was no movement of the fresh ground‐water body with respect to the underlying salt water prior to waste injection, and “dynamic” experiments in which a fresh ground‐water flow field was present prior to and during waste injection. During every experiment conducted in this study, buoyant plumes of injected effluent, which were clearly distinct from the resident aquifer liquids, formed and migrated upward into the lower portion of the fresh‐water body. Three injection parameters exerted significant control on the movement of the injection plumes; the rate of effluent injection and the strength of the ambient fresh‐water flow field significantly influenced both the vertical and lateral migration of the plumes, and the depth of effluent injection (with respect to the salt/ fresh‐water interface) influenced the over‐all shape of the plumes as well as the lateral migration of the plumes. The principal means of plume movement in these experiments appears to be by fluid displacement processes, rather t

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1978.tb03255.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTThere is a spectrum of sea‐level fluctuations that affect the water table of a small, permeable oceanic island. At the high‐frequency end of the spectrum are the semi‐diurnal and diurnal components of the astronomical tides. Also affecting sea‐level elevation are atmospheric pressure and the temperature and salinity (hence density) of the ocean column.Changes in atmospheric pressure cause sea‐level changes on the order of up to about 30 cm, by what oceanographers call the “inverted barometer effect.” As a result, pressure changes, like tides, generate waves that migrate across the water table. Amplitudes of the resultant pressure‐related water‐table fluctuations diminish inland. However, owing to the relatively long period of the pressure‐related fluctuations, their inland attenuation is far less than that of the hydraulically analogous tides. In fact, in Bermuda for example, the pressure‐related water‐table fluctuations completely dominate water‐table statistics that reflect day‐to‐day changes in elevation.Because a drop in pressure and corresponding rise in the water table accompanies passage of a storm front, which also brings a rainfall, there is commonly a coincidental, and very misleading, correlation between rainfalls and water‐table rises. In island and coastal settings, non‐tidal sea‐level changes and their effect on the water table must be taken into account, if recharge is to be correc

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1978.tb03256.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTThe city of San Bernardino is in a semiarid inland valley about 60 miles (100 kilometers) east of Los Angeles. The southern part of the city is traversed by the San Jacinto fault. Adjacent to the upgradient (northeast) side of the fault is a 10 square mile (26 square kilometers) area which contains a zone in the alluvial ground‐water basin that formerly was under artesian pressure and consisted of swampy lands with a history of flowing wells, springs, and ground‐water discharge to Warm Creek.Since about 1945, water levels have declined more than 100 feet (30 meters), and the swampy lands have dried up and are now highly urbanized. Basin replenishment by artificial recharge of imported northern California water at the base of the San Bernardino Mountains may cause ground‐water levels to rise again in the area that was formerly swampy land. If this should happen, building foundations and basements could be subjected to structural damage and flooding by renewed flowing of unplugged artesian wells.The U.S. Geological Survey, in cooperation with the San Bernardino Valley Municipal Water District, is developing a two‐layer digital model to aid in predicting the rate and extent of the rise in water levels. The solution to the mathematical equations used in the model was approximated numerically by the Galerkin finite‐element method. The water district desires to evaluate water management alternatives, such as varying location, distribution, amounts of recharge, and pumping centers, to avoid excessive water level rises that could indicate an overfilling of the basin and could cau

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1978.tb03257.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTThe analysis of flow to a flowing nonpenetrating well in a leaky artesian aquifer was obtained. A method has been suggested to determine the aquifer parameters using the pump‐test data on such wells with constant drawdown in the well. A technique is also suggested to determine the aquifer parameters using the well itself as the observation wel

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1978.tb03258.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTThe impact of the use of a heat pump for residential heating and cooling on ground‐water temperatures was simulated by means of a mathematical model which couples the equations for ground‐water flow with those for heat transport. A hypothetical case using data typical for southern Wisconsin was considered. Water was pumped from and recharged to a sandstone aquifer using a two‐well system. Water was withdrawn from a deep well and injected into a shallow well during the heating cycle and during the cooling cycle the system was operated in reverse. After ten years of operation, water temperatures in the aquifer had changed less than one degree centigrade at a distance of greater than 40 meters from the wells. For the case considered, the use of heat pumps for residential heating and cooling would not adversely lower ground‐water temperatures if use were restricted to sparsely populated areas. It is recommended that statutes which prohibit the injection of water directly into the subsurface be changed to allow the use of ground‐water h

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1978.tb03259.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY