地下水数值模拟课件.pptxVIP

地下水数值模拟Numerical Simulation of Groundwater Some Basic Concepts Groundwater, or subsurface water, is a term used to denote all the waters found beneath the surface of the ground.-- J. Bear, Hydraulics of Groundwater, 1979 The term groundwater is usually reserved for the subsurface water that occurs beneath the water table in soils and geologic formations that are fully saturated.-- R.A.Freeze, J.A.Cherry, Groundwater, 1979 ???????????????????????????????????????????????Unconsolidated RockPorous medium Limestone Igneous Rock (Granite) Fractured Igneous Rock (Basalt) Hydrology Hydrogeology Hydrology is the study of water. In the broadest sense, hydrology addresses the occurrence, distribution, movement, and chemistry of all waters of the earth. Hydrogeology encompasses the interrelationships of geologic materials and processes with water.-- C.W. Fetter, Applied Hydrogeology, 2001 An aquifer is a geologic formation, or a group of formations, which (1) contains water and (2) permits significant amounts of water to move through it under ordinary field conditions. An aquitard is a geologic formation which is of a semi-pervious nature; it transmits water at a very low rate compared to the aquifer.-- J. Bear, Hydraulics of Groundwater, 1979 A confined aquifer, is one bounded from above and from below by impervious formations. A phreatic aquifer (also called unconfined aquifer, water table aquifer) is one in which a water table serves as its upper boundary.-- J. Bear, Hydraulics of Groundwater, 1979 Aquifers A porous medium domain is said to be homogeneous if its permeability is the same at all its points. Otherwise, the domain is said to be heterogeneous (or inhomogeneous). If, however, the permeability at a considered point is independent of direction, the medium is said to be isotropic at that point.-- J. Bear, Hydraulics of Groundwater, 1979 Transmissivity (T)Transmissivity is a measure of the amount of waterthat can be transmitte