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Environmental engineers handbook - Chapter 9 docx

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Principles of Groundwater Flow 9.1 GROUNDWATER AND AQUIFERS Definition of Groundwater Aquifers Physical Properties of Soils and Liquids Physical Properties of Soils Physical Properties of Water Physical Properties of Vadose Zones and Aquifers Physical Properties of Vadose Zones Physical Properties of Aquifers 9.2 FUNDAMENTAL EQUATIONS OF GROUNDWATER FLOW Intrinsic Permeability Validity of Darcy’s Law Generalization of Darcy’s Law Equation of Continuity Fundamental Equations 9.3 CONFINED AQUIFERS One-Dimensional Horizontal Flow Semiconfined Flow Radial Flow Radial Flow in a Semiconfined Aquifer Basic Equations 9.4 UNCONFINED AQUIFERS Discharge Potential and Continuity Equation Basic Differential Equation One-Dimensional Flow Radial Flow Unconfined Flow with Infiltration One-Dimensional Flow with Infiltra- tion Radial Flow with Infiltration Radial Flow from Pumping with Infil- tration 9.5 COMBINED CONFINED AND UNCONFINED FLOW One-Dimensional Flow Radial Flow Hydraulics of Wells 9.6 TWO-DIMENSIONAL PROBLEMS Superposition A Two-Well System A Multiple-Well System Method of Images Well Near a Straight River Well Near a Straight Impervious Boundary Well in a Quarter Plane Potential and Flow Functions 9 Groundwater and Surface Water Pollution ©1999 CRC Press LLC GROUNDWATER POLLUTION CONTROL Yong S. ChaeԽAhmed Hamidi 9.7 NONSTEADY (TRANSIENT) FLOW Transient Confined Flow (Elastic Storage) Transient Unconfined Flow (Phreatic Storage) Transient Radial Flow (Theis Solu- tion) 9.8 DETERMINING AQUIFER CHARACTER- ISTICS Confined Aquifers Steady-State Transient-State Semiconfined (Leaky) Aquifers Steady-State Transient-State Unconfined Aquifers Steady-State Transient-State Slug Tests 9.9 DESIGN CONSIDERATIONS Well Losses Specific Capacity Partially Penetrating Wells (Imperfect Wells) Confined Aquifers Unconfined Aquifers 9.10 INTERFACE FLOW Confined Interface Flow Unconfined Interface Flow Upconing of Saline Water Protection Against Intrusion Principles of Groundwater Contamination 9.11 CAUSES AND SOURCES OF CONTAMI- NATION Waste Disposal Liquid Waste Solid Waste Storage and Transport of Commercial Materials Storage Tanks Spills Mining Operations Mines Oil and Gas Agricultural Operations Fertilizers Pesticides Other Activities Interaquifer Exchange Saltwater Intrusion 9.12 FATE OF CONTAMINANTS IN GROUND- WATER Organic Contaminants Hydrolysis Oxidation–Reduction Biodegradation Adsorption Volatilization Inorganic Contaminants Nutrients Acids and Bases Halides Metals 9.13 TRANSPORT OF CONTAMINANTS IN GROUNDWATER Transport Process Advection Dispersion Retardation Contaminant Plume Behavior Contaminant Density Contaminant Solubility Groundwater Flow Regime Geology Groundwater Investigation and Monitoring 9.14 INITIAL SITE ASSESSMENT Interpretation of Existing Information Site-Specific Information Regional Information Initial Field Screening Surface Geophysical Surveys Downhole Geophysical Surveys Onsite Chemical Surveys 9.15 SUBSURFACE SITE INVESTIGATION Subsurface Drilling Drilling Methods Soil Sampling ©1999 CRC Press LLC ©1999 CRC Press LLC Monitoring Well Installation Well Location and Number Casings and Screens Filter Packs and Annular Seals Well Development Groundwater Sampling Purging Collection and Pretreatment Quality Assurance and Quality Control Groundwater Cleanup and Remediation 9.16 SOIL TREATMENT TECHNOLOGIES Excavation and Removal Physical Treatment Soil–Vapor Extraction Soil Washing Soil Flushing Biological Treatment Slurry Biodegradation Ex Situ Bioremediation and Land- farming In Situ Biological Treatment Thermal Treatment Incineration Thermal Desorption Stabilization and Solidification Treat- ment Stabilization Vitrification 9.17 PUMP-AND-TREAT TECHNOLOGIES Withdrawal and Containment Systems Well Systems Subsurface Drains Treatment Systems Density Separation Filtration Carbon Adsorption Air Stripping Oxidation and Reduction Limitations of Pump-and-Treat Technol- ogies 9.18 IN SITU TREATMENT TECHNOLOGIES Bioremediation Design Considerations Advantages and Limitations Air Sparging Design Considerations Advantages and Limitations Other Innovative Technologies Neutralization and Detoxification Permeable Treatment Beds Pneumatic Fracturing Thermally Enhanced Recovery 9.19 INTEGRATED STORM WATER PROGRAM Integrated Management Approach Federal Programs State Programs Municipal Programs 9.20 NONPOINT SOURCE POLLUTION Major Types of Pollutants Nonpoint Sources Atmospheric Deposition Erosion Accumulation/Washoff Direct Input from Pollutant Source 9.21 BEST MANAGEMENT PRACTICES Planning Land Use Planning Natural Drainage Features Erosion Controls Maintenance and Operational Practices Urban Pollutant Control Collection System Maintenance Inflow and Infiltration Drainage Channel Maintenance 9.22 FIELD MONITORING PROGRAMS Selection of Water Quality Parameters Acquisition of Representative Samples Sampling Sites and Location Sampling Methods Flow Measurement Sampling Equipment Manual Sampling Automatic Sampling Flowmetering Devices QA/QC Measures Sample Storage Sample Preservation Analysis of Pollution Data Storm Loads Annual Loads Simulation Model Calibration Statistical Analysis 9.23 DISCHARGE TREATMENT Biological Processes Physical-Chemical Processes Physical Processes Swirl-Flow Regulator-Concentrator Sand Filters Enhanced Filters Compost Filters ©1999 CRC Press LLC STORM WATER POLLUTANT MANAGEMENT David H.F. LiuԽKent K. Mao This section defines groundwater and aquifers and dis- cusses the physical properties of soils, liquids, vadose zones, and aquifers. Definition of Groundwater Water exists in various forms in various places. Water can exist in vapor, liquid, or solid forms and exists in the at- mosphere (atmospheric water), above the ground surface (surface water), and below the ground surface (subsurface water). Both surface and subsurface waters originate from precipitation, which includes all forms of moisture from clouds, including rain and snow. A portion of the precip- itated liquid water runs off over the land (surface runoff), infiltrates and flows through the subsurface (subsurface flow), and eventually finds its way back to the atmosphere through evaporation from lakes, rivers, and the ocean; transpiration from trees and plants; or evapotranspiration from vegetation. This chain process is known as the hy- drologic cycle. Figure 9.1.1 shows a schematic diagram of the hydrologic cycle. Not all subsurface (underground) water is groundwa- ter. Groundwater is that portion of subsurface water which occupies the part of the ground that is fully saturated and flows into a hole under pressure greater than atmospheric pressure. If water does not flow into a hole, where the pressure is that of the atmosphere, then the pressure in wa- ter is less than atmospheric pressure. Depths of ground- water vary greatly. Places exist where groundwater has not been reached at all (Bouwer 1978). The zone between the ground surface and the top of groundwater is called the vadose zoneor zone of aeration. This zone contains water which is held to the soil parti- cles by capillary force and forces of cohesion and adhe- sion. The pressure of water in the vadose zone is negative due to the surface tension of the water, which produces a negative pressure head. Subsurface water can therefore be classified according to Table 9.1.1. Groundwater accounts for a small portion of the world’s total water, but it accounts for a major portion of the world’s freshwater resources as shown in Table 9.1.2. Table 9.1.2 illustrates that groundwater represents about 0.6% of the world’s total water. However, except for glaciers and ice caps, it represents the largest source of freshwater supply in the world’s hydrologic cycle. Since much of the groundwater below a depth of 0.8km is saline or costs too much to develop, the total volume of readily usable groundwater is about 4.2 million cubic km (Bouwer 1978). Groundwater has been a major source of water supply throughout the ages. Today, in the United States, ground- water supplies water for about half the population and supplies about one-third of all irrigation water. Some three- fourths of the public water supply system uses ground- water, and groundwater is essentially the only water source for the roughly 35 million people with private systems (Bouwer 1978). Aquifers Groundwater is contained in geological formations, called aquifers,which are sufficiently permeable to transmit and yield water. Sands and gravels, which are found in allu- vial deposits, dunes, coastal plains, and glacial deposits, are the most common aquifer materials. The more porous the material, the higher yielding it is as an aquifer mater- ial. Sandstone, limestone with solution channels, and other Karst formations are also good aquifer materials. In gen- eral, igneous and metamorphic rocks do not make good aquifers unless they are sufficiently fractured and porous. Figure 9.1.2 schematically shows the types of aquifers. The two main types are confined aquifersand unconfined aquifers.A confined aquifer is a layer of water-bearing ma- terial overlayed by a relatively impervious material. If the confining layer is essentially impermeable, it is called an aquiclude.If it is permeable enough to transmit water ver- tically from or to the confined aquifer, but not in a hori- zontal direction, it is called an aquitard.An aquifer bound by one or two aquitards is called a leakyor semiconfined aquifer. Confined aquifers are completely filled with ground- water under greater-than-atmospheric pressure and there- fore do not have a free water table.The pressure condi- tion in a confined aquifer is characterized by a piezometric surface,which is the surface obtained by connecting equi- librium water levels in tubes or piezometers penetrating the confined layer. ©1999 CRC Press LLC Principles of Groundwater Flow 9.1 GROUNDWATER AND AQUIFERS An unconfined aquifer is a layer of water-bearing ma- terial without a confining layer at the top of the ground- water, called the groundwater table,where the pressure is equal to atmospheric pressure. The groundwater table, sometimes called the freeor phreatic surface,is free to rise or fall. The groundwater table height corresponds to the equilibrium water level in a well penetrating the aquifer. Above the water table is the vadoze zone, where water pressures are less than atmospheric pressure. The soil in the vadoze zone is partially saturated, and the air is usu- ally continuous down to the unconfined aquifer. Physical Properties of Soils and Liquids The following discussion describes the physical properties of soils and liquids. It also defines the terms used to de- scribe these properties. PHYSICAL PROPERTIES OF SOILS Natural soils consist of solid particles, water, and air. Water and air fill the pore space between the solid grains. Soil can be classified according to the size of the particles as shown in Table 9.1.3. Soil classification divides soils into groups and sub- groups based on common engineering properties such as texture, grain size distribution,and Atterberg limits. The most widely accepted classification system is the unified classification system which uses group symbols for identi- fication, e.g., SW for well-graded sand and CH for inor- ganic clay of high plasticity. For details, refer to any stan- dard textbook on soil mechanics. Figure 9.1.3 shows an element of soil, separated in three phases. The following terms describe some of the engi- neering and physical properties of soils used in ground- water analysis and design: ©1999 CRC Press LLC Return Flow from Irrigation Groundwater Flow (Saturated Flow) Groundwater Table Flow from Septic Tanks Freshwater-Salt Water Interface Tr Return SR Lake E SR ET Spring E ET (from Vegetation) ET = Evapotranspiration E = Evaporation Tr = Transpiration SR = Surface Runoff In = Infiltration SR SR E In Snow and Ice Sublimation Precipitation (on Land) Clouds Clouds Tr Precipitation (on the Coast) Movement of Moist Air Masses Ocean Sea Water Leakage Unsaturated Flow River FIG. 9.1.1Schematic diagram of the hydrologic cycle. TABLE 9.1.1CLASSIFICATION OF SUBSURFACE WATER Vadoze Soil Water Subsurface Zone Intermediate Vadoze Water Water Capillary Water Zone of Groundwater Saturation (Phreatic Water) Internal Water POROSITY (n)—A measure of the amount of pores in the material expressed as the ratio of the volume of voids (V v ) to the total volume (V), n = V v /V. For sandy soils n = 0.3 to 0.5; for clay n > 0.5. VOID RATIO (e)—The ratio between V v and the volume of solids V S , e = V v /V S ; where e is related to n as e = n/(1 – n). WATER CONTENT (␻)—The ratio of the amount of water in weight (W W ) to the weight of solids (W S ), ␻ = W W /W S . DEGREE OF SATURATION (S)—The ratio of the volume of water in the void space (V W ) to V v , S = V W /V v . S varies between 0 for dry soil and 1 (100%) for saturated soil. COEFFICIENT OF COMPRESSIBILITY (␣)—The ratio of the change in soil sample height (h) or volume (V) to the change in applied pressure (␴ v ) ␣ = Ϫ ᎏ 1 h ᎏ ᎏ d d ␴ h v ᎏ = Ϫ ᎏ V 1 ᎏ ᎏ d d ␴ V v ᎏ 9.1(1) The ␣ can be expressed as ␣ = ᎏ (1 + E ␮ (1 )( Ϫ 1 Ϫ ␮ ) 2 ␮ ) ᎏ = 9.1(2) where: E ϭ Young’s modulus ␮ ϭ Poisson’s ratio B ϭ bulk modulus G ϭ shear modulus Clay exists in either a dispersed or flocculated structure depending on the arrangement of the clay particles with 1 ᎏ B + ᎏ 4 3 ᎏ G ©1999 CRC Press LLC TABLE 9.1.2 ESTIMATED DISTRIBUTION OF WORLD’S WATER Volume Percentage of 1000 km 3 Total Water Atmospheric water 13.25 000.001 Surface water Salt water in oceans 1,320,000.25 097.2 Salt water in lakes and inland seas 104.25 000.008 Fresh water in lakes 125.25 000.009 Fresh water in stream channels (average) 1.25 000.0001 Fresh water in glaciers and icecaps 29,000.25 002.15 Water in the biomass 50.25 000.004 Subsurface water Vadose water 67.25 000.005 Groundwater within depth of 0.8 km 4200.25 000.31 Groundwater between 0.8 and 4 km depth 4200 0.31 Total (rounded) 1,360,000.25 100 Source: H. Bouwer, 1978, Groundwater hydrology (McGraw-Hill, Inc.). Aquifer C Aquifer B Aquifer A Interface Leakage Interface Sea Water Sea Perched Water Water Table Flowing Well Ground Surface Recharge Area Leakage Piezometric surface (B) Piezometric surface (C) ConfinedPhreatic Leaky Artesian Confined Leaky Aqui er B Impervious Stratum Semipervious Stratum FIG. 9.1.2 Types of aquifers. the type of cations that are adsorbed to the clay. If the layer of adsorbed cation (such as C a ϩϩ ) is thin and the clay particles can be close together, making the attractive van der Waals forces dominant between the particles, then the clay is flocculated. If the clay particles are kept some dis- tance apart by adsorbed cations (such as N ϩ a ), the repul- sive electrostatic forces are dominant, and the clay is dis- persed. Since clay particles are negatively charged, which can adsorb cations from the soil solution, clay can be con- verted from a dispersed state to a flocculant condition through the process of cation exchange (e.g. N ϩ a ®C a ϩϩ ) which changes the adsorbed ions. The reverse, changing from a flocculated to a dispersed clay, can also occur. Clay structure change is used to handle some groundwater prob- lems in clay because the hydraulic properties of soil are dependent upon the clay structure. PHYSICAL PROPERTIES OF WATER The density of a material is defined as the mass per unit volume. The density ( ␳ ) of water varies with temperature, pressure, and the concentration of dissolved materials and is about 1000 kg/m 3 . Multiplying ␳ by the acceleration of gravity (g) gives the specific weight ( ␥ ) as ␥ Ϸ ␳ g. For wa- ter, ␥ Ϸ 9.8 kN/m 3 . Some of the physical properties of water are defined as follows: DYNAMICVISCOSITY ( ␮ )—The ratio of shear stress ( ␶ yx ) in x direction, acting on an x–y plane to velocity gradient (dv x /dy); ␶ yx ϭ ␮ dv x /dy. For water, ␮ ϭ 10 Ϫ3 kg/m⅐s. KINEMATICVISCOSITY ( ␷ )—Related to ␮ by ␷ ϭ ␮ / ␳ . Its value is about 10 Ϫ6 m 2 /s for water. COMPRESSIBILITY ( ␤ )—The ratio of change in density caused by change in pressure to the original density ␤ ϭ ᎏ 1 ␳ ᎏ ᎏ d d p ␳ ᎏ ϭϪ ᎏ V 1 ᎏ ᎏ d d V p ᎏ ␤ Ϸ0.5 ϫ10 Ϫ9 m 2 /N 9.1(3) The variation of density and viscosity of water with temperature can be obtained from Table 9.1.4. Physical Properties of Vadose Zones and Aquifers A description of the physical properties of vadose zones and aquifers follows. PHYSICAL PROPERTIES OF VADOSE ZONES As discussed earlier, the pressure of water in the vadose zone is negative, and the negative pressure head or capil- lary pressure is proportional to the vertical distance above the water table. Figure 9.1.4 shows a characteristic curve ©1999 CRC Press LLC TABLE 9.1.3USUAL SIZE RANGE FOR GENERAL SOIL CLASSIFICATION TERMINOLOGY Material Upper, mm Lower, mm Comments Boulders, cobbles 1000 ϩ 75 Ϫ Gravel, pebbles 75 2–5 No. 4 or larger sieve Sand 2–5 0.074 No. 4 to No. 200 sieve Silt 0.074–0.05 0.006 Inert Rock flour 0.006 Inert Clay 0.002 0.001 Particleattraction,water absorption Colloids 0.001 Source:J.E. Bowles, 1988, Foundation analysis and design,4th ed. (McGraw-Hill). FIG. 9.1.3Three-phase relationship in soils. ( c ) Air W g Х 0 W w W s 1 ϩ e 1 ϭ W s /␥ w G s e W w / ␥ w V V s V ␷ V w V a ( b ) V ␷ V s 1.0 e 1 Ϫ n 1.00 n V ϭ 1 ϩ e Air Water Soil ( a ) V V s V ␷ V w V a W s W w W of the relationship between volumetric water content and the negative pressure head (height above the water table or capillary pressure). For materials with relatively uniform particle size and large pores, the water content decreases abruptly once the air-entry value is reached. These materials have a well-de- fined capillary fringe. For well-graded materials and ma- terials with fine pores, the water content decreases more gradually and has a less well-defined capillary fringe. At a large capillary pressure, the volumetric water con- tent tends towards a constant value because the forces of adhesion and cohesion approach zero. The volumetric wa- ter content at this state is equal to the specific retention. The specific retention is then the amount of water retained against the force of gravity compared to the total volume of the soil when the water from the pore spaces of an un- confined aquifer is drained and the groundwater table is lowered. PHYSICAL PROPERTIES OF AQUIFERS As stated before, an aquifer serves as an underground stor- age reservoir for water. It also acts as a conduit through which water is transmitted and flows from a higher level to a lower level of energy. An aquifer is characterized by the three physical properties: hydraulic conductivity, trans- missivity, and storativity. Hydraulic Conductivity Hydraulic conductivity, analogous to electric or thermal conductivity, is a physical measure of how readily an aquifer material (soil) transmits water through it. Mathe- matically, it is the proportionality between the rate of flow and the energy gradient causing that flow as expressed in the following equation. Therefore, it depends on the prop- erties of the aquifer material (porous medium) and the fluid flowing through it. K ϭ k ᎏ ␮ ␥ ᎏ 9.1(4) where: K ϭ hydraulic conductivity (called the coefficient of per- meability in soil mechanics) k ϭ intrinsic permeability ␥ ϭ specific weight of fluid ␮ ϭ dynamic viscosity of fluid For a given fluid under a constant temperature and pres- sure, the hydraulic conductivity is a function of the prop- erties of the aquifer material, that is, how permeable the soil is. The subject of hydraulic conductivity is discussed in more detail in Section 9.2. Transmissivity Transmissivity is the physical measure of the ability of an aquifer of a known dimension to transmit water through it. In an aquifer of uniform thickness d, the transmissivity T is expressed as T ϭ _ Kd 9.1(5) where _ K represents an average hydraulic conductivity. When the hydraulic conductivity is a continuous function of depth _ K ϭ ᎏ 1 d ᎏ ͵ d o Kz dz 9.1(6) When a medium is stratified, either in horizontal (x) or vertical (y) direction with respect to hydraulic conductiv- ity as shown in Figure 9.1.5, the average value _ K can be obtained by _ K x ϭ Α n mϭ1 ᎏ K m d d m ᎏ 9.1(7) ©1999 CRC Press LLC TABLE 9.1.4 VARIATION OF DENSITY AND VISCOSITY OF WATER WITH TEMPERATURE Temperature Density Dynamic Viscosity (°C) (kg/m 3 ) (kg/m s) 0 999.868 1.79 ϫ 10 Ϫ3 5 999.992 1.52 ϫ 10 Ϫ3 10 999.727 1.31 ϫ 10 Ϫ3 15 999.126 1.14 ϫ 10 Ϫ3 20 998.230 1.01 ϫ 10 Ϫ3 Source: A. Verrjuitt, 1982, Theory of groundwater flow, 2d ed. (Macmillan Publishing Co.). FIG. 9.1.4 Schematic equilibrium water-content distribution above a water table (left) for a coarse uniform sand (A), a fine uniform sand (B), a well-graded fine sand (C), and a clay soil (D). The right plot shows the corresponding equilibrium water- content distribution in a soil profile consisting of layers of ma- terials A, B, and D. 0.1 0.2 0.3 0.4 0.5 100 200 300 0.1 0.2 0.3 0.4 0.5 100 200 300 0 0 D B A A D C B VOLUMETRIC WATER CONTENT DISTANCE ABOVE WATER TABLE IN CM _ K y ϭ 9.1(8) Storativity Storativity, also known as the coefficient of storageor spe- cific yield,is the volume of water yielded or released per d ᎏ Α n mϭ1 ᎏ K d m m ᎏ unit horizontal area per unit drop of the water table in an unconfined aquifer or per unit drop of the piezometric sur- face in a confined aquifer. Storativity S is expressed as S ϭ ᎏ A 1 ᎏ ᎏ d d Q ␾ ᎏ 9.1(9) where: dQϭvolume of water released or restored d ␾ ϭ change of water table or piezometric surface Thus, if an unconfined aquifer releases 2 m 3 water as a result of dropping the water table by 2m over a hori- zontal area of 10 m 2 , the storativity is 0.1 or 10%. —Y.S. Chae Reference Bouwer, H. 1978. Groundwater hydrology.McGraw-Hill, Inc. ©1999 CRC Press LLC FIG. 9.1.5Permeability of layered soils. Direction of flow Direction of flow x y d k 1 k 2 k n d n d 1 d 2 9.2 FUNDAMENTAL EQUATIONS OF GROUNDWATER FLOW The flow of water through a body of soil is a complex phenomenon. A body of soil constitutes, as described in Section 9.1, a solid matrix and pores. For simplicity, as- sume that all pores are interconnected and the soil body has a uniform distribution of phases throughout. To find the law governing groundwater flow, the phenomenon is described in terms of average velocities, average flow paths, average flow discharge, and pressure distribution across a given area of soil. The theory of groundwater flow originates with Henry Darcy who published the results of his experimental work in 1856. He performed a series of experiments of the type shown in Figure 9.2.1. He found that the total discharge Q was proportional to cross-sectional area A, inversely proportional to the length ⌬s, and proportional to the head difference ␾ 1 Ϫ ␾ 2 as expressed mathematically in the form Q ϭKA ᎏ ␾ 1 ⌬ Ϫ s ␾ 2 ᎏ 9.2(1) where K is the proportionality constant representing hy- draulic conductivity. This equation is known as Darcy’s equation. The quantity Q/A is called specific dischargeq. If ␾ 1 Ϫ ␾ 2 ϭ⌬ ␾ and ⌬s ® 0, Equation 9.2(1) becomes q ϭϪK ᎏ d d ␾ s ᎏ 9.2(2) This equation states that the specific discharge is directly proportional to the derivative of the head in the direction of flow (hydraulic gradient). The specific discharge is also known as Darcy’s velocity. Note that q is not the actual flow velocity (seepage velocity) because the flow is limited to pore space only. The seepage velocity v is then Reference level p 1 lpg p 2 lpg ␾ 2 ␾ 1 z 1 z 2 Area A Flow ⌬ s FIG. 9.2.1Darcy’s experiment. [...]... 10.5 10.2 10.1 10.0 09. 84 09. 77 09. 68 09. 55 09. 50 09. 43 09. 33 09. 29 09. 23 09. 14 09. 11 09. 06 08 .99 08 .96 08 .92 08.86 08.83 08.80 08.74 08.72 08.68 08.63 8.63 8.45 8.23 7 .94 7.84 7.72 7.53 7.47 7.38 7.25 7.20 7.13 7.02 6 .98 6 .93 6.84 6.81 6.76 6. 69 6.66 6.62 6.55 6.53 6. 49 6.44 6.41 6.38 6.33 6.33 6.15 5 .93 5.64 5.54 5.42 5.23 5.17 5.08 4 .95 4 .90 4.83 4.73 4. 69 4.63 4.54 4.51 4.47 4. 39 4.36 4.32 4.26 4.23... 30.5 30.4 30.3 30.2 30.2 30.0 30.0 30.0 29. 9 29. 8 29. 8 29. 7 29. 7 29. 6 29. 6 29. 6 29. 5 29. 5 29. 4 29. 4 29. 4 29. 4 29. 2 29. 0 28.7 28.6 28.4 28.3 28.2 28.1 28.0 27 .9 27 .9 27.7 27.7 27.7 27.6 27.5 27.5 27.4 27.4 27.3 27.3 27.3 27.2 27.2 27.1 27.1 27.1 27.1 26 .9 26.6 26.4 26.3 26.1 26.0 25 .9 25.8 25.7 25.6 25.5 25.4 25.4 25.3 25.3 25.2 25.2 25.1 25.1 25.0 25.0 24 .9 24 .9 24 .9 24.8 24.8 24.8 24.8 24.6 24.3 24.1... 02.8 296 03.0 493 03.2 898 03.5533 03.8416 04.1573 04.5028 04.8808 05. 294 5 05.7472 06.2426 06.7848 07.3782 08.0277 08.7386 09. 51 69 10.3 690 11.30 19 0.0000 0.0501 0.1005 0.1517 0.2040 0.25 79 0.3137 0.37 19 0.43 29 0. 497 1 0.5652 0.6375 0.7147 0. 797 3 0.8861 0 .98 17 1.0848 1. 196 3 1.3172 1.4482 1. 590 6 1.7455 1.8280 2. 097 8 2. 298 1 2.5167 2.7554 3.0161 3.3011 3.6126 3 .95 34 4.3262 4.7342 5.1810 5.6701 6.2058 6. 792 7... 4 .92 5.00 5.02 0.240 0.468 0.675 0.850 1.010 1.15 1.28 1. 39 1.50 1.58 2.20 2.54 2.76 2 .95 3. 09 3.20 3.26 3.36 3.45 3 .90 4.12 4.26 4.40 4.50 4.58 4.65 4.70 4.80 0. 192 0.378 0.555 0.710 0.850 0 .97 0 1. 09 1.20 1. 29 1.38 1 .98 2.32 2.54 2.72 2.85 2 .99 3.05 3.15 3.22 3.68 3 .90 4.04 4. 19 4.26 4.35 4.40 4. 49 4.52 0.158 0.316 0.465 0.600 0.725 0.840 0 .95 0 1.04 1.14 1.22 1.80 2.14 2.36 2.52 2.67 2.80 2.86 2 .96 ... 3. 69 4.00 3 .90 3.78 4.10 3 .95 3.82 4.15 4.00 3 .90 4. 19 4.05 3 .92 Continued on next page 0.08 0. 09 © 199 9 CRC Press LLC TABLE 9. 7.4 Continued tЈ rЈ 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0. 09 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 .9 1 2 3 4 5 6 7 8 9 10 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 .9 1 2 3 4 0. 093 0.187 0.278 0.368 0.450 0.530 0.610 0.680 0.750 0.815 1.32 1.64 1.86 2.03 2.16 2.28 2.36 2.45 2.54 2 .97 ... Cooper and Jacob ( 194 6) and Chow ( 195 2) for confined aquifers, and Hantush and Jacob ( 195 5), Neuman and Witherspoon ( 196 9), Walton ( 196 2), Boulton ( 196 3) and Neuman ( 197 2) for unconfined aquifers 10 1 0-1 1 1 0-2 1 0-1 -4 10 1 0-3 3 10 Confined Aquifers This section discusses the methods used in determining aquifer characteristics for confined aquifers Matching Point 1 0-3 104 1 0-2 1 0-1 105 106 r2/t IN... 4.20 4.14 4.12 4. 09 4.04 4.04 3.86 3.64 3.35 3.26 3.14 2 .96 2 .90 2.81 2.68 2.63 2.57 2.47 2.43 2.38 2.30 2.26 2.22 2.15 2.12 2. 09 2.03 2.00 1 .97 1 .92 1 .90 1.87 1.82 1.82 1.66 1.46 1.22 1.15 1.04 0 .90 6 0.858 0. 794 0.702 0.670 0.625 0.560 0.536 0.503 0.454 0.437 0.411 0.374 0.360 0.340 0.311 0.300 0.284 0.260 0.251 0.2 39 0.2 19 0.2 19 0.158 0.100 0.04 89 0.0372 0.02 49 0.0130 0.0101 0.00 697 0.00378 0.00300... 22 .9 22 .9 22.8 22.8 22.7 22.7 22.6 22.6 22.6 22.5 22.5 22.4 Source: H Bouwer, 197 8, Groundwater hydrology (McGraw-Hill, Inc.) 22.4 22.3 22.0 21.8 21.7 21.5 21.3 21.3 21.2 21.1 21.0 20 .9 20.8 20.8 20.7 20.7 20.6 20.6 20.5 20.5 20.4 20.4 20.3 20.3 20.3 20.2 20.2 20.1 20.1 20.0 19. 7 19. 5 19. 4 19. 2 19. 0 19. 0 18 .9 18.8 18.7 18.6 18.5 18.5 18.4 18.4 18.3 18.3 18.2 18.2 18.1 18.1 18.0 18.0 17 .9 17 .9 17 .9 17.8... 6.35 0 .95 1.52 1.88 2.17 2.38 2.56 2.70 2.84 2 .95 3.04 3.66 4.01 4.26 4.45 4.56 4.68 4.80 4 .90 4 .95 5.35 5.60 5.75 5.85 5 .95 6.05 6.10 6.15 6.20 0.875 1.42 1. 79 2.06 2.28 2.45 2.60 2.72 2.84 2 .94 3.56 3 .90 4.15 4.30 4.45 4.55 4.65 4.75 4.83 5.25 5.50 5.70 5.80 5.85 5 .95 6.05 6.10 6.14 0.474 0.860 1.18 1.42 1.60 1.78 1 .91 2.04 2.14 2.25 2.87 3.24 3.46 3.65 3.76 3 .90 3 .96 4.05 4.10 4. 59 4.82 4 .95 5.05... 7.4358 8.1404 8 .91 28 9. 7 595 ϱ 2.4271 1.7527 1.3725 1.1145 0 .92 44 0.7775 0.6605 0.5653 0.4867 0.4210 0.3656 0.3185 0.2782 0.2436 0.2138 0.1880 0.1655 0.14 59 0.1288 0.11 39 0.1008 0.0 893 0.0 791 0.0702 0.0624 0.0554 0.0 493 0.0438 0.0 390 0.0347 0.0310 0.0276 0.0246 0.0220 0.0 196 0.0175 0.0156 0.0140 0.0125 0.0112 ϱ 9. 8538 4.7760 3.0560 2.1844 1.6564 1.3028 1.0503 0.8618 0.7165 0.60 19 0.5 098 0.4346 0.3726 . Viscosity (°C) (kg/m 3 ) (kg/m s) 0 99 9.868 1. 79 ϫ 10 Ϫ3 5 99 9 .99 2 1.52 ϫ 10 Ϫ3 10 99 9.727 1.31 ϫ 10 Ϫ3 15 99 9.126 1.14 ϫ 10 Ϫ3 20 99 8.230 1.01 ϫ 10 Ϫ3 Source: A. Verrjuitt, 198 2, Theory of groundwater. 01.6467 0 .98 17 0.2138 0.2774 1.6 01.7500 1.0848 0.1880 0.2406 1.7 01.8640 1. 196 3 0.1655 0.2 094 1.8 01 .98 96 1.3172 0.14 59 0.1826 1 .9 02.1277 1.4482 0.1288 0.1 597 2.0 02.2 796 1. 590 6 0.11 39 0.1 399 2.1. 0.1228 2.2 02.6 291 1.8280 0.0 893 0.10 79 2.3 02.8 296 2. 097 8 0.0 791 0. 095 0 2.4 03.0 493 2. 298 1 0.0702 0.0837 2.5 03.2 898 2.5167 0.0624 0.07 39 2.6 03.5533 2.7554 0.0554 0.0653 2.7 03.8416 3.0161 0.0 493 0.0577 2.8

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Mục lục

  • Contents

  • Groundwater and Surface Water Pollution

    • Principles of Groundwater Flow

      • 9.1 GROUNDWATER AND AQUIFERS

        • Definition of Groundwater

        • Aquifers

        • Physical Properties of Soils and Liquids

          • PHYSICAL PROPERTIES OF SOILS

          • Physical Properties of Vadose Zones and Aquifers

            • PHYSICAL PROPERTIES OF WATER

            • PHYSICAL PROPERTIES OF VADOSE ZONES

            • PHYSICAL PROPERTIES OF AQUIFERS Transmissivity

            • Hydraulic Conductivity

            • Storativity

            • Reference

            • 9.2 FUNDAMENTAL EQUATIONS OF GROUNDWATER FLOW

              • Intrinsic Permeability

              • Generalization of DarcyÌs Law

              • Validity of DarcyÌs Law

              • Equation of Continuity

              • Fundamental Equations

              • 9.3 CONFINED AQUIFERS

                • One-Dimensional Horizontal Flow

                • Radial Flow

                • Semiconfined Flow

                • Radial Flow in a Semiconfined Aquifer

                • Basic Equations

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