Stochastic analysis of ground-water flow in semiconfined aquifer

Stochastic analysis of ground-water flow in semiconfined aquifer

HYDROGEOLOGY:GROUNDWATER in good agreement for all values of power law indices for wall heat flux and non-Newtonian fluid. -Authors 944035 Stochastic...

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HYDROGEOLOGY:GROUNDWATER in good agreement for all values of power law indices for wall heat flux and non-Newtonian fluid. -Authors

944035 Stochastic fluid travel times in heterogeneous porous media W. E. Hathhom & R. J. Charbeneau, Journal of Hydraulic Engineering - ASCE, 120(2), 1994, pp 134-146. An analytic approach is developed for quantifying the distribution of fluid passage times in a heterogeneous porous medium. The basle methodology employed utilizes a diffusion theory desc.ri~tion for the displacement of a purely advected fluid subject to a random field of hydraulic conductivity. Within this framework, a governing model is formed usin~ the backward form of the statistical Kolmogorge equauon, which yields the inverse Gaussian distribution as a solution to the fluid passage time problem. -from Authors

944036 Stochastic analysis of ground-water flow in semiconflned aquifer M. G. Satish & Jianting Zhu, Journal of Hydraulic Engineering- ASCE, 120(2), 1994, pp 147-168. A stochastic analysis for two-dimensional steady-state ground-water flow through a homogeneous random shallow semiconflned aquifer is presented. The flow problems through a semiconflned aquifer with a random leakage factor but subject to deterministic boundary conditions and domain recharge are investigated by perturbation techniques associated with the boundary element method. The leakage factor is related to the physical properties of both the main aquifer and the leaky layer. -from Authors 944037 Construction of equivalent discontinuum models for fracture hydrology J. C. S. Long, in: Comprehensive rock engineering. Vol. 3, ed J.A. Hudson, (Pergamon), 1993, pp 241-295. A line of reasoning is presented that could be applied at a fractured site to deduce a model for the hydrological behavior of the system. The main points of this approach are: 1) that interdisciplinary interaction is a critical part of maximizing understanding and reducing uncertainty; and 2) that an equivalent discontinuum model for fracture flow based on behavior and constructed from the top down may be an appropriate approach for modeling some sites. This chapter attempts to describe how the elements of different efforts can be linked and related to a final product. -from Author 944038 Preliminary modellinjg of groundwater inflows at Gays River mine, Nova Scotm, Canada R. MacLeod, G. G. Bursey, T. R. C. Aston & J. E. Gale,

~3"ansactions Institution of Mining & Metallurgy, Section

179A

tucky (Breathitt Group) manifest visible evidence of alteration related to fluid flow localized through near-vertical joints. Fracture-related alterations involve both physical and chemical modifications that together create dramatic permeability variations at the outcrop scale. Petrographic evidence suggests that most of the iron that now resides in oxidized anthigen/c phases was derived from solutes mobilized through dissolution of older iron-bearing anthigenic minerals. The large magnitude of permeability variafion around fracture systems in these sandstones documents the presence of a dual porosity system and suggests that fluid and contaminant transport cannot be realistically modeled using average rock properties. -Authors

944040 Hydrogeologic analysis of the saturated-zone round-water system, under Yucca Mountain, Nevada • J. Fridrich, W. W. Dudley Jr & J. S. Stuckless, Journal of Hydrology, 154(1-4), 1994, pp 133-168. The geologic features of a zone of large gradient under Yucca Mountain suggest two possible hydrogeologic models. First, the northern bounding fault of the buried graben may provide a highly permeable pathway (a drain) through the brittle lavas in the lower part of the volcanic section under northern Yucca Mountain. Alternatively, the northern bounding fault of the buried graben may be the effective northern limit of the tuff aquifer under Yucca Mountain because the permeability in the tufts north of the fault may have been diminished by hydrothermal alteration. In either case, heads in the tuff aquifer in the area of very small gradient may be regulated partly by upward flow from the deep carbonate aquifer. -from Authors 944041 Analysis of pumping tests, with regard to tectonics, hydrothermal effects and weathering, for fractured Dalha and stratiform basaits, Republic of Djibouti M. Jalludin & M. Razack, Journal of Hydrology, 155(1-2), 1994, pp 237-250. The Republic of Djibouti is the location of an exceptional geodynamic situatton, the Afar Depression, which is an emerged triple junction of the Red Sea, the Gulf of Aden and the East A.fi'ican rifts, where a fault network is particularly well developed and controls the permeability of volcanic aquifers, t'umping test data are analysed for two major basaltic series, the stratiform series (3.4-1 Ms) and the Dalha series (9-3.4 Ms), which are distinguished mainly by their gcodynamic characteristics and geological history although they axe both recognized as trap rocks. The results describe aquifers in the stratifonn and Dalha basalts which are identified by different hydrodynamic characteristics. -from Authors

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A, 102(Sept-Dec), 1993, pp A153-A164. The Gays River lead-zinc mine in central Nova Scotia, Canada, lies within a complex hydrolo$ical regime and underground mining environment. Origmally opened in 1979, the operation was severely affected by an inability to control inflows of mine water. In 1989, the reopened mining operations were hampered by an inability to maintain consistent drainage of groundwater to the underground workings and to sustain low groundwater levels. A threedimensional finite-element computer code CFEST (Coupled fluid, energy and solute transport), was used to model the system of groundwater flow around the mine on both regional and local scales. Improved simulation of the conditions of high inflow can probably be achieved by determining the hydraulic conductivity of the river-bed and floodplain sediments and modelling sinkhole features wimin the Gays River and its surrounding floodplain as discrete units. Several possible methods of reducing the amount of inflow water to the mine workings are discussed. -from Authors

944039 Porosity and permeability variations in fractured and liesel[ang-banded Breathitt sandstones (Middle Pennsylvaman), eastern Kentucky: diagenetic controis and implications for modeling dual-porosity systems L. Fu, K. L. Milliken & J. M. Sharp Jr, Journal of Hydrology, 154(1-4), 1994, pp 351-381. Middle Pennsylvanian fluvial sandstones in eastern KenRI~$ 31:4-I

944042 The fault pattern in the northern Negev and southern coastal plain of Israel and its hydrogeological implications for groundwater flow in the Judea Group aquifer G. Weinberger & E. Rosenthal, Journal of Hydrology, 155(1-2), 1994, pp 103-124. The hydrogeological properties of the Judea Group sequence of Israel have been reassessed. A new regional pattern of faults extending through the subsurface of the study area has been revealed. The Judea Group aquifer hould not be re~arded as one continuous and undisturbed ydrological umt; owing to the occurrence of regional faults, its sub.a¢luifers are locally interconnected. ~'hese subaquifers, which contain mainly high-quality water, are juxtaposed, as a result of faulting, against Kumub Group sandstones containing brackish ~paleowater. The latter Group is faulted against late Jurasslc formations containing highly saline groundwater. In the southern Coastal Plain, major faults locally dissect also the Pleistocene Kurkar Group, facilitating inflow of Mg-rich groundwater deriving from~Judea Group dolomites. The new geological evidence provides new solutions for previously unexplained salinization phenomena. -from Authors 944043 On the geoelectro-jgeohydraulic analogy research project in the river plains o f northern Croatm A. Satin & Z. Brkic, Geologia Croatica, 46(2), 1993, pp 307-311. The use of the electro-hydraulic analogy, i.e. the hydraulic