ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1983.tb00740.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTA comparative study was undertaken on the decay rates of three bacterial types (S. typhimurium, E. coliandS. faecalis), an enterovirus (poliovirus type 1) and a bacterial phage (f2) in ground water maintained under laboratory conditions. Except for f2 phage, all the microorganisms tested were relatively stable in ground water.S. faecalissurvived best among all the bacteria tested and its decay rate was similar to that of poliovirus type 1.Under field conditions, bacterial indicators were also found to be stable in the ground‐water environment. The decay rate for fecal streptococci was lower than for fecal or total coliforms in the shallow well

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1983.tb00741.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTNumerical models can be used to aid in the design and licensing of dewatering and depressurizing systems by simulating changes in hydraulic head produced by the interference patterns of various configurations and pumping rates of wells, wellpoints, or ejectors. The total quantity of water that must be pumped to achieve the desired objective can be approximated by modeling the inflow rate into a network of constant‐head nodes located around the perimeter of an excavation and assigning a hydraulic‐head value to these nodes equivalent to the average level to which the water table or potentiometric surface would be lowered by a dewatering or depressurizing system. As a result, it is possible to determine the decrease in the inflow rate as the flow system goes from the period of transient flow, when significant quantities of water are released from storage in unconfined aquifers and hydraulic gradients are steeper, to the period of steady‐state flow when no water is released from storage and hydraulic gradients are flatter. Based on the inflow rate data, simulations can be made showing the effectiveness of various pumping well configurations. In these simulations, the number, location, and pumping rates of wells can be varied to design a dewatering or depressurizing system that maximizes well interference and drawdown with a minimum number of wells. Decreases in the inflow rate during transient flow can be accounted for by adjusting well discharge rates during the transient flow period.Simulation results can be used to determine the radius of influence of the system, calculate induced drawdown in nearby wells, determine the amount of time required for predrainage prior to construction, calculate the amount of induced infiltration from nearby surface

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1983.tb00742.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTA technique has been developed for the determination of the exchangeable cation population of calcareous sandy material with cation exchange capacities of less than 1 meq/100 g. The technique involves the addition of exchange salt in the dry state to samples of porous media using original pore water as the exchange salt solvent. In applying this technique to samples from below the water table, the amount of pore water available for reaction is reduced by centrifuging in the field to bring the moisture content close to field capacity values. By utilizing the minimum amount of pore water, interferences during the exchange process due to calcite precipitation or dissolution are minimized. The extent of calcite dissolution or precipitation that occurs can be appraised by measuring alkalinity or total carbon on the pore water before and after addition of the exchange salt. Three salts, NH4C1, CsCl and LiCl were tested for their suitability for this technique. CsCl was found to be preferable because of its low tendency to dissolve carbonate and the preference of Cs+on exchange sites.Application of the method to a field site in southern Ontario yielded a value of 0.51 ± 0·09 meq/100 g over 15 samples for the cation exchange capacity of a near surface glaciofluvial sand deposit. It is believed that this technique could be applied with reasonable accuracy and reproducibility to materials with exchange capacities of as low as 0·1 meq/100

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1983.tb00743.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTThe ages and origins of saline ground waters in coastal aquifers can be important indicators of local aquifer flow characteristics. Unfortunately, attempts to classify such waters using established trilinear diagram techniques are frequently inconclusive due largely to the dominance of sodium and chloride ions. In a study of saline ground waters from the Chalk limestone of eastern central England, an alternative, less conventional, dilution diagram procedure is employed which reveals previously unrecognized differences in local major ion chemical character. These differences are interpreted in terms of the origins of the saline ground waters and their histories of mixing. Significantly, the interpretations reinforce and, in some cases, refine earlier interpretations based on notably less extensive minor ion and environmental isotope data. It is concluded that the saline ground waters are associated with at least three periods of saline intrusion during the past 120,000 years.

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1983.tb00744.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTThe streambed‐leakage factor ranged from 0.11 to 1.68 million gallons per day per acre per foot of head loss. Most values for the streambed infiltration rate and the streambed‐leakage factor for six tests before 1970 were higher than for six tests in 1976–79, suggesting a change in streambed permeability in the intervening time.A well field to serve a government‐owned uranium enrichment facility, consisting initially of 4 wells, later increased to 15 wells, was designed to yield up to 20 million gallons per day. The wells are on a line parallel to the river at distances from the stream ranging from 122 to 330 feet. Distance between wells ranges from 190 to 303 feet. Specific capacities of the wells, based on 24‐hour acceptance tests, ranged from 63 to 147 gallons per minute per foot of drawdown and averaged 100 gallons per minute per foot of drawdown. By late Summer of 1976, pumpage from all 15 wells ranged from 12 to 15 million gallons per day. Drawdown was about as expected, based on design criteria developed from the aquifer tests, except that pumping levels were lower than expected in the Fall and Winter of 1976–77, resulting from low streamflow and low river

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1983.tb00745.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTAfter analysis of the geological, hydrological, hydrochemical, isotope, and pumping test data of the karst aquifer in the Mesozoic Tripolitza carbonates of the Molai area, it was concluded that the carbonates contain two flow systems. The western system discharges through the shore and submarine springs at Glyfada into the Gulf of Lakonia; its catchment, which has no exploitable reservoir, is connected to the springs by a narrow conduit related to a fracture zone in marbles that accompany the Molai fault. The eastern flow system, along the northern fringe of the Molai Plain, has a reservoir with acceptable (less than 120 m deep) pumping levels; its water quality, however, is variable. The system discharges, probably by dispersed seepage flow, into the Aegean Sea. The unusual characteristics of the karst in the Molai area can be explained by the continuous tectonic activity which has prevented the completion of various stages of karst development.

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1983.tb00746.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTVast deposits of oil shale are contained in the Piceance basin in northwestern Colorado. The basin may contain as much as 40 million acre‐feet of stored water associated with these deposits, much of which may have to be drained for mining. Yet, most analyses of watersupply for oil‐shale development have focused on surface water with only brief mention of ground water.This study used a synthetic streamflow model to investigate the effects of using conservative estimates of ground water on the required active storage capacity of a hypothetical reservoir on the White River. Results of the study indicate that use of ground water from mine drainage and/or auxiliary wells may have a significant impact on the size and timing of surface‐water reservoirs. Thus, ground water may be an important source of supply, particularly during early development of an oil‐shale industry. The study results strongly suggest that further investigations are needed on the physical availability of ground water as well as the institutional, legal and waterquality constraints on

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1983.tb00747.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTThe upconing of the salt‐water interface in an unconfined coastal aquifer due to water withdrawal by an infiltration gallery is analyzed numerically based on the variational formulation of the problem. Sometimes in coastal areas, from the point of view of safe withdrawal of water on a long‐term basis, the use of an infiltration gallery is found to be feasible in preventing severe upconing of the interface that would have resulted from heavy pumpage by a vertical well. The numerical procedure presented here is capable of delineating profiles of the free surface and interface along with the length of the outflow face and quantity of freshwater flow to the sea. Full consideration of the nonlinear boundary conditions on the free surface and interface is included for a steady flow towards a gallery in both isotropic and anisotropic aquifers. The extent of upconing of the interface under different operating conditions of the gallery for different aquifer geometries has been studied. A general understanding of the flow phenomenon in the vicinity of the gallery has been established. The results of the analysis can be used to plan a water withdrawal scheme without causing contamination by salt wa

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1983.tb00748.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Abstract. Observations on the collapse of a medieval castle built on an artificial mound testify that contemporary slippage was adroitly accommodated by building adjustments. However, 300 years of continuous usage without an effective waste disposal system eventually caused the latrine tower to collapse.

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1983.tb00749.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY