ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01323.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractShoreline recession on the Great Lakes has caused millions of dollars worth of property damage in the lake bordering States and Canadian provinces. A variety of projects have been funded to study the erosion problem. The general conclusion of these studies is that wave action at the base of the bluff is the most important basic cause of bluff‐top retreat. The purpose of this study was to investigate the role of various physical processes in causing bluff erosion. One part of the study was to ascertain the role of ground water in bluff stability. In this study, along a certain stretch of the Lake Michigan shoreline, 9 to 10 m (27 to 30 ft) per year of bluff‐top recession that is not correlated to toe erosion was recorded. Heads were measured in 25 piezometers and a complex ground‐water flow system was defined at this site. A glacial sand unit that is under artesian pressure was found 5 m (15 ft) above the toe of the bluff. Another “perched” system was observed in a fractured till unit at the top of the bluff. Water‐table fluctuations have been recorded over a year and fluctuations of up to 13 m (39 ft) in the lower sand unit were measured. These fluctuations were found to have a significant influence on bluff stability. Pore pressures calculated from field measurements, along with the effective strength parameters of the soil units, were then used in the slope stability analysis to determine safety factors.Ground‐water flow systems are found to be highly complex at the land‐lake interface due to the inhomogeneities of the glacial materials that compose the bluffs. Furthermore, these complex ground‐water flow systems influence the stability of the upper part of the bluffs. Because of the complexities, extrapolation of results to other stretches of the shoreline is difficult. However, methodologies and the awareness of how water‐table fluctuations and multi‐layered ground‐water flow systems affect slope stability can be of help in

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01324.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThe flow of ground water in a fractured rock aquifer may be linear toward a natural production surface rather than radial toward a pumping well, if the well penetrates a fracture having a permeability many orders of magnitude greater than the permeability of the surrounding aquifer. The well and its hydraulically connected production surface are called an extended well. Flow lines in a linear system are parallel, and drawdown is a function of the perpendicular distance from the extended well and not a function of the radius of the pumped well. The location of a concealed fracture and hydraulic diffusivity of the linear system can be determined if drawdown data from two observation wells are available.Linear flow has been recognized in fractured rock aquifers from aquifer test data in three widely separated areas of New Mexico and probably is the cause of the anomalous response observed in fractured rock aquifers in Mendocino and Placer Counties, California. Test data were curvilinear on semi‐log plots and straight lines on log‐log plots, suggesting that traditional methods of aquifer test analysis are not applicable. Straight lines could be fitted to arithmetic plots of pumped well and observation well data when plotted as drawdown versus √t, indicating that the flow in the vicinity of the test well is linear. Linear flow may be a common phenomenon that has been overlooked in the analysis of aquifer tests in fractured rock aqu

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01325.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractTwo earthfill sections of Wallace Dam on the Oconee River near Eatonton, Georgia were constructed with vertical drainage filters (chimney drains) in a clay fill zone. In order to evaluate the performance of the filter in the west dike of Wallace Dam, the finite element Galerkin method was utilized in formulating a numerical model to study the steady‐state saturated‐unsaturated seepage characteristics through the earth dam. The resulting model is applied to Station 58+00 of the west dike of Wallace Dam. Numerical results for the four cases analyzed in this study describe the location of the zero pressure isobar and total hydraulic head values ranging from 425 feet (130 m) to 365 feet (111 m). Model results indicate a maximum seepage velocity of 2.62 feet per day (0.80 m/day) using a saturated horizontal hydraulic conductivity of 0.283 foot per day (8.64 cm/day). A maximum seepage rate is calculated to be 0.266 cubic foot per second (7.52 × 10−3m3/sec). Analysis of the hydrostatic uplift forces along the base of the dam indicates an average pressure head reduction of 51 feet (16 m) from the upstream to the downstream side of the dam. Comparison of local seepage velocities to the critical seepage velocity upstream of the filter and inside the filter indicate a factor of safety against piping (a factor of safety against a quick condition arising in the soil) ranging from 0.3

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01326.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThe Underground Injection Control Program Regulations require that an “area of review” be determined for new injection wells.Analytical equations may be used to determine pressure buildup in disposal zones. However, in reviewing areas that have numerous injection wells discharging into the same zone, care must be used to take into account the effect of all the injection wells on the pressure buil

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01327.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThermal and mineral waters from the Cascade Mountains can be divided, on a chemical basis, into three groups. Chemically homogeneous waters that issue from the geothermally attractive Central Cascades comprise Group 1. The individuality of Group 1 is exhibited by a neutral pH, total dissolved solids averaging 2650 parts per million (ppm), dominant Cl and Na ions, and less significant amounts of Ca, SO4, SiO2, HCO3, K, B, and Mg, listed in order of decreasing abundance. The chemistry and uniformity of these waters suggests that many of the dissolved constituents were derived through prolonged contact with Eocene marine sediments deposited in a Mesozoic structural embayment prior to volcanic events.Acid‐sulfate waters from the vents of Mt. Lassen, Newberry Crater, and Mt. Hood represent Group 2. These fumarolic waters have a chemistry that results when H2S in rising volcanic steam oxidizes forming sulfuric acid. Basic brines discharge at the base of Mt. Lassen and Mt. Hood; these may be in hydraulic connection with the fumaroles.The majority of Cascadian waters are included within Group 3, and are characterized by chemical inhomogeneity between individual points of discharge. Total dissolved solids average 1620 ppm, with dominant Cl, Na, HCO3, and SO4ions, and less significant concentrations of Ca, SiO2, K, Mg, and B; the pH ranges from 6.2 to 9.7. The Cascade Province possesses complex volcanic stratigraphy and varying degrees of hydrothermal alteration. In addition, the thermal waters have been subjected to differing degrees of mixing and proximity to heat, thus chemical inhomogeneity might be expected.Isotopic evidence indicates that all Cascadian thermal and mineral waters were oringinally meteoric. Wateres from Groups 1 and 3 individually show linear relationships between cl and Na; for both groups, cl/Na is similar to that of SMOW, suggesting some recycling of the dominant ion

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01328.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThe ground‐water observation well network in many parts of Kansas has been developed and expanded through the years without serious attempt to determine the adequacy of the network for any specified purpose or to assess its cost effectiveness. This study was undertaken to examine the existing well network in northwest Kansas and to determine the arrangement that offers the most satisfactory accuracy for the purpose of monitoring it. To achieve this goal, we have employed the theory of regionalized variables to estimate the amount of spatial variability of the water table. The error analysis produced by universal kriging indicates that a significant reduction in the number of wells could be achieved by employing a regular 4‐mile (6.4‐km) network, without affecting the present level of accuracy. It also indicates that it is not practical to reduce the estimation error in the water‐table surface uniformly throughout the region because to do so would increase the cost of monitoring wells drastically. For example, reducing the presently existing error by 50 percent throughout the area would require 16 times more wells than the currently existing well

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01329.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01330.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractGround water meets 40% of California's annual water needs, yet is essentially unmanaged. Current overdrafting is of special concern because supplemental surface supplies are becoming scarcer and more expensive. A dynamic optimization model is used to show that potential benefits from management in the southern San Joaquin area may be substantial. The magnitude of these benefits is sensitive to costs of energy, interest rates, demand for water, and availability of substitute surface supplies. The distribution of benefits from management depends upon the regulatory strategy employed. Collectively, pumpers gain through quota regulation but lose with pump taxes. Individual pumpers may lose even if the collective group benefits.Existing arrangements for ground‐water management in California appear inadequate. Statutes permit State regulation of withdrawals where water quality is threatened but only if additional surface supplies are provided. Management may be initiated in the courts at considerable cost. Historically, court action has required supplemental surface supplies. Legal authority exists for local control of withdrawals but has never been used.Resistance to ground‐water management in California is widespread and stems from the perception that regulation may impose real losses on individual users even if the majority benefits. Individual fears of economic loss borne for the collective and uncertain gain to larger group constitutes a significant barrier to management Effective management policies will need to be simple, flexible, equitable and inexpensive to adminis

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01331.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThe development of Arizona ground‐water policy has been evolutionary. Courts and the State legislature have responded to particular problems, but until recently have stopped short of a comprehensive framework for such policy. This paper identifies and describes the major political forces of change responsible for reform of ground‐water law in Arizona. Historical developments surrounding the development of such policy are examined to interpret these forces of change. A detailed historical account of the development of Arizona ground‐water policy provides a useful perspective from whichto examine the principal forces of change driving the reform of this portion of State water policy.Arizona ground‐water policy has evolved from a previous policy of nonmanagement to “after the fact” management currently embodied in the 1980 Groundwater Management Act. Changing social attitudes and political challenges have continued to alter the institutional framework of the water policy‐making process ultimately shifting the arena from the judicial to the legislature. After nearly half a century of political conflict, judicial decision and legislative response, Arizona enacted a comprehensive ground‐water code.Political forces characterized by repeated Federal threat affecting a major reclamation project and special interest group pressures resulting from a 1976 judicial decision combined with the physical realities of ground‐water exploitation to force reform in the State ground‐water policy. Due to high decision costs, such reform was achieved through structural decisions delegating the more difficult allocative decisions to special interests directly affected by the ultimate policy. In turn and out of political necessity, a far‐reaching, progressive legislative proposal for ground‐water policy became the product of a delicately negotiated compromise among competing water interests achieved through the process of agreement. After the major decision costs had been incurred through such negotiations, the reform initiative was then ratified by the State legislature as the 1980 Arizona Groundwater Management Act, absent the tremendous political costs otherwise inevitable to

ISSN:0017-467X    

DOI:10.1111/j.1745-6584.1982.tb01332.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY