9285.9-15B
EPA540/R-95/001
FOREWORD
This manual is for reference use of students enrolled in scheduled training courses of the U.S.
Environmental Protection Agency (EPA). While it will be useful to anyone who needs information
on the subjects covered, it will have its greatest value as an adjunct to classroom presentations
involving discussions among the students and the instructional staff.
This manual has been developed with a goal of providing the best available current information;
however, individual instructors may provide additional material to cover special aspects of their
presentations.
Because of the limited availability of the manual, it should not be cited in bibliographies or other
publications. n
References to products and manufacturers are for illustration only; they do not. imply endorsement
by EPA.
Constructive suggestions for improvement of the content and format of the manual are welcome.
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INTRODUCTION TO GROUNDWATER INVESTIGATIONS
(165.7)
3 Days
This introductory course is designed to provide participants with information concerning
hydrogeological processes and the necessary elements of a sound groundwater site investigation. It
is intended for personnel who are involved in groundwater contamination investigations but have
little prior hydrogeological experience. This course is not designed for geologists or
hydrogeologists.
Topics that are discussed include hydrogeological definitions and concepts; basic geology and
geochemistry; drilling, construction, and placement of monitoring wells; groundwater sampling
considerations; groundwater flow rates; and groundwater modeling.
Instructional methods include lectures, group discussions, case studies, and class problem-solving
exercises.
After completing the course, participants will be able to:
• Identify the components of a groundwater system.
• List the primary hydrogeological factors to be considered in a site investigation.
• Construct a flow net and calculate the hydraulic gradient of a simple system.
• Discuss the primary advantages and disadvantages of the most common geophysical
survey methods.
• Identify the different types of pumping tests and the information that can be obtained
from each.
• Describe monitoring well drilling and sampling techniques.
U.S. Environmental Protection Agency
Office of Emergency and Remedial Response
Environmental Response Team
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CONTENTS
Acronyms and Abbreviations
Glossary
SECTION 1
SECTION 2
SECTION 3
SECTION 4
SECTION 5
SECTION 6
SECTION 7
SECTION 8
SECTION 9
SECTION 10
SECTION 11
STANDARD ORIENTATION AND INTRODUCTION
GEOLOGY
HYDROGEOLOGY
THE HYDROGEOLOGICAL INVESTIGATION
Checklist for a Hydrogeological Investigation
GEOPHYSICAL METHODS
MONITORING THE VADOSE ZONE
WELL CONSTRUCTION
H YDROGEOCHEMISTR Y
GROUNDWATER FLOW RATES AND MODELING
PROBLEM EXERCISES
Problem 1—Flow Net Construction
Problem 2—Geologic Cross-Section Construction
Problem 3—Aquifer Tests
Problem 4—Groundwater Investigation
APPENDICES
Appendix A—Sampling Protocols
Appendix 1—References
Appendix C—Sources of Information
1/95
Contents
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ACRONYMS AND ABBREVIATIONS
ACS
American Chemical Society
AGI
American Geological Institute
ARAR
applicable or relevant and
appropriate requirement
ASTM
American Society for Testing
and Materials
ATSDR
Agency for Toxic Substances
and Disease Registry
atm
atmosphere
BDAT
best demonstrated available
technology
BM
Bureau of Mines
BNA
base/neutral/acid extractables
BOD
biochemical oxygen demand
BTEX
benzene, toluene, ethylbenzene,
and xylenes
CAA
Clean Air Act
CDC
Centers for Disease Control
CE
current electrode
CERCLA
Comprehensive Environmental
Response, Compensation and
Liability Act of 1980
CERCLIS
CERCLA Information System
CERI Center for Environmental
Research Information
CFR Code of Federal Regulations
CLP Contract Laboratory Program
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CFA
continuous flight auger
COC
chain of custody
COD
chemical oxygen demand
COE
U.S. Army Corps of Engineers
CWA
Clean Water Act
DO
dissolved oxygen
DOJ
U.S. Department of Justice
DOT
U.S. Department of
Transportation
DQO
data quality objectives
DRI
direct-reading instruments
DNAPL
dense, nonaqueous phase liquid
Eh
oxygen-reduction potential
EM
electromagnetic
EMSL-LV
Environmental Monitoring
Systems Laboratory - Las
Vegas
EPtox
toxicity-extraction procedure
toxicity
EPA
U.S. Environmental Protection
Agency
EPIC
Environmental Photographic
Interpretation Center
ER
electrical resistivity
ERP
Emergency Response Plan
Acronyms and Abbreviations
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ERT
EPA Emergency Response
Team
ERTS
Earth Resources Technology
Satellite
EROS
Earth Resources Observation
Systems
ESB
EPA Environmental Services
Branch
ESD
Environmental Services
Division
eV
electron volt
FIFRA
Federal Insecticide, Fungicide,
and Rodenticide Act
nT
field investigation team
FRP
fiberglass reinforced plastic
FS
feasibility study
FSP
field sampling plan
GAC
granular activated carbon
GC
gas chromatograph
GC/MS
gas chromatography/mass
spectrometry
gpm
gallons per minute
GPR
ground-penetrating radar
GWA
Ground Water Act of 1987
HASP
health and safety plan (see also
site safety plan)
HAZMAT
hazardous materials team
HRS
hazard ranking system
HSL
hazardous substance list
(previous term for target
compound list)
HSA
hollow-stem auger
HSO
health and safety officer (see
also SSC, SSHO, and SSO)
HSWA
Hazardous and Solid Waste
Amendments (to RCRA, 1984)
HWS
hazardous waste site
ICS
incident command system
IDL
instrument detection limit
IDLH
immediately dangerous to life
and health
IP
ionization potential
IR
infrared (spectroscopy)
K
hydraulic conductivity
LEL
lower explosive limit
LNAPL
light, nonaqueous phase liquid
LUST
leaking underground storage
tank
MCL
maximum contaminant level
MCLG
maximum contaminant level
goal
MDL
method detection limit
MSL
mean sea level
m/sec
meters per second
MHz
megahertz
Acronyms and Abbreviations
2
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MS/MS mass spectrometry/mass
spectrometry
NEAR nonbinding preliminary
allocation of responsibility
NCIC National Cartographic
Information Center
NCP National Oil and Hazardous
Substances Pollution
Contingency Plan
NEIC National Enforcement
Investigation Center
NIOSH National Institute of
Occupational Safety and Health
NIPDWR National Interim Primary
Drinking Water Regulations
NOAA National Oceanic and
Atmospheric Administration
n.o.s. not otherwise specified (used
in shipping hazardous material)
NPDES National Pollutant Discharge
Elimination System
NPL National Priorities List
NRC Nuclear Regulatory
Commission
NSF National Sanitation Foundation
NTIS National Technical Information
Service
NWS National Weather Service
OERR EPA Office of Emergency and
Remedial Response
OHMTADS Oil and Hazardous Materials
Technical Assistance Data
System
OSHA
OSWER
OVA
OWPE
PAC
PAH
PCB
PCDD
PCDF
PCP
PE
PEL
PID
PO
POHC
POM
POTWs
ppb
Occupational Safety and Health
Administration
EPA Office of Solid Waste and
Emergency Response
organic vapor analyzer (onsite
organic vapor monitoring
device)
EPA Office of Waste Programs
Enforcement
powdered activated carbon
polycyclic aromatic
hydrocarbons
poly chlorinated biphenyls
polychlorinated dibenzo-p-
dioxin
polychlorinated dibenzofuran
pentachlorophenol
potential electrode
permissible exposure limit
photoionization detector
project officer (EPA)
principle organic hazardous
constituent
polycyclic organic matter
publicly owned treatment
works
parts per billion
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Acronyms and Abbreviations
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PPE
personal protective equipment
PPm
parts per million
PRP
potentially responsible party
psig
pounds per square inch gauge
PVC
polyvinyl chloride
QA
quality assurance
QA/QC
quality assurance and quality
control
QAMS
quality assurance management
staff
QC
quality control
RA
remedial action
RAS
routine analytical services
RCRA
Resource Conservation and
Recovery Act of 1978
RD
remedial design
REM
remedial planning
REM/FIT
remedial planning/field
investigation team
RI/FS
remedial investigation and
feasibility study
ROD
record of decision
RPM
EPA remedial project manager
RQ
reportable quantity
RSPO
remedial site project officer
RSCC
Regional Sample Control
Center
SARA
Superfund Amendments and
Reauthorization Act of 1986
SAS
special analytical services
SCBA
self-contained breathing
apparatus
ses
Soil Conservation Service
SDL
sample detection limit
SDWA
Safe Drinking Water Act
SI
site inspection
SITE
Superfund Innovative
Technology Evaluation
SM
site manager
SOP
standard operating procedure
SP
spontaneous potential
SQG
small quantity generator
SSC
site safety coordinator
SVOC
semivolatile organic
compound
SWDA
Solid Waste Disposal Act
TAT
technical assistance team
TCLP
toxicity characteristic leaching
procedure
TEGD
Technical Enforcement
Guidance Document
TDS
total dissolved solids
TLV
threshold limit value
TOC
total organic carbon
Acronyms and Abbreviations
4
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(
TOH
total organic halogen
TOX
total organic halides
TSCA
Toxic Substances Control Act
TSDF
treatment, storage, and disposal
facility
TUHC
total unburned hydrocarbons
UEL
upper explosive limit
UMTRCA
Uranium Mill Tailing Radiation
Control Act
USCG
United States Coast Guard
uses
Unified Soil Classification
System
USDI
U.S. Department of the Interior
USGS
U.S. Geological Survey
UST
underground storage tank
UV
ultraviolet
VOA
volatile organic analysis
VOC
volatile organic compound
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Acronyms and Abbreviations
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GLOSSARY
acre-foot
adsorption
advection
alluvium
anisotropic
aquifer
aquifer test
aquitard
artesian
artificial recharge
artesian aquifer
bedload
enough water to cover 1 acre to a depth of 1 foot; equal to 43,560
cubic feet or 325,851 gallons
the attraction and adhesion of a layer of ions from an aqueous solution
to the solid mineral surfaces with which it is in contact
the process by which solutes are transported by the bulk motion of the
flowing groundwater
a general term for clay, silt, sand, gravel, or similar unconsolidated
material deposited during comparatively recent geologic time by a
stream or other body of running water as a sorted or semisorted
sediment in the bed of the stream or on its floodplain or delta, or as
a cone or fan at the base of a mountain slope
hydraulic conductivity ("K"), differing with direction
a geologic formation, group of formations, or a part of a formation
that contains sufficient permeable material to yield significant
quantities of groundwater to wells and springs. Use of the term
should be restricted to classifying water bodies in accordance with
stratigraphy or rock types. In describing hydraulic characteristics such
as transmissivity and storage coefficient, be careful to refer those
parameters to the saturated part of the aquifer only.
a test involving the withdrawal of measured quantities of water from,
or the addition of water to, a well (or wells) and the measurement of
resulting changes in head (water level) in the aquifer both during and
after the period of discharge or addition
a saturated, but poorly permeable bed, formation, or group of
formations that does not yield water freely to a well or spring
confined; under pressure sufficient to raise the water level in a well
above the top of the aquifer
recharge at a rate greater than natural, resulting from deliberate or
incidental actions of man
see confined aquifer
the part of the total stream load that is moved on or immediately above
the stream bed, such as the larger or heavier particles (boulders,
pebbles, gravel) transported by traction or saltation along the bottom;
the part of the load that is not continuously in suspension or solution
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1
Glossary
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capillary zone
capture
coefficient of storage
cone of depression
confined
confined aquifer
confining bed
diffusion
discharge area
discharge velocity
dispersion
drawdown
effective porosity
Glossary
negative pressure zone just above the water table where water is drawn
up from saturated zone into soil pores due to cohesion of water
molecules and adhesion of these molecules to soil particles. Zone
thickness may be several inches to several feet depending on porosity
and pore size.
the decrease in water discharge naturally from a ground-water
reservoir plus any increase in water recharged to the reservoir
resulting from pumping
the volume of water an aquifer releases from or takes into storage per
unit surface area of the aquifer per unit change in head
depression of heads surrounding a well caused by withdrawal of water
(larger cone for confined aquifer than for unconfined)
under pressure significantly greater than atmospheric throughout and
its upper limit is the bottom of a bed of distinctly lower hydraulic
conductivity than that of the material in which the confined water
occurs
geological formation capable of storing and transmitting water in
usable quantities overlain by a less permeable or impermeable
formation (confining layer) placing the aquifer under pressure
a body of "impermeable" material stratigraphically adjacent to one or
more aquifers
the process whereby particles of liquids, gases, or solids intermingle
as a result of their spontaneous movement caused by thermal agitation
an area in which subsurface water, including both groundwater and
water in the unsaturated zone, is discharged to the land surface, to
surface water, or to the atmosphere
an apparent velocity, calculated from Darcy's law, which represents
the flow rate at which water would move through the aquifer if it were
an open conduit (also called specific discharge)
the spreading and mixing of chemical constituents in groundwater
caused by diffusion and by mixing due to microscopic variations in
velocities within and between pores
the vertical distance through which the water level in a well is lowered
by pumping from the well or a nearby well
the amount of interconnected pore space through which fluids can
pass, expressed as a percent of bulk volume. Part of the total porosity
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evapotranspiration
flow line
fluid potential
gaining stream
groundwater
groundwater divide
groundwater model
groundwater reservoir
groundwater system
head
heterogeneous/geological
formation
homogeneous
hydraulic conductivity "K"
will be occupied by static fluid being held to the mineral surface by
surface tension, so effective porosity will be less than total porosity.
the combined loss of water from direct evaporation and through the
use of water by vegetation (transpiration)
the path that a particle of water follows in its movement through
saturated, permeable rocks (synonym: streamline)
the mechanical energy per unit mass of water or other fluid at any
given point in space and time, with respect to an arbitrary state of
datum
a stream or reach of a stream whose flow is being increased by inflow
of groundwater (also called an effluent stream)
water in the zone of saturation
a ridge in the water table or other potentiometric surface from which
groundwater moves away in both directions normal to the ridge line
simulated representation of a groundwater system to aid definition of
behavior and decision-making
all rocks in the zone of saturation (see also aquifer)
a groundwater reservoir and its contained water; includes hydraulic
and geochemical features
combination of elevation above datum and pressure energy imparted
to a column of water (velocity energy is ignored because of low
velocities of groundwater). Measured in length units (i.e., feet or
meters).
characteristics varying aerially or vertically in a given system
geology of the aquifer is consistent; not changing with direction or
depth
volume flow through a unit cross-section area per unit decline in head
(measured in velocity units and dependent on formation characteristics
and fluid characteristics)
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Glossary
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hydraulic gradient
change of head values over a distance
W, -H,
hydrograph
impermeable
infiltration
interface
intrinsic permeability
isotropic
laminar flow
losing stream
mining
nonsteady state-nonsteady
shape
where:
H = head
L = distance between head measurement points
graph that shows some property of groundwater or surface water as a
function of time
having a texture that does not permit water to move through it
perceptibly under the head difference that commonly occurs in nature
the flow or movement of water through the land surface into the
ground
in hydrology, the contact zone between two different fluids
pertaining to the relative ease with which a porous medium can
transmit a liquid under a hydrostatic or potential gradient. It is a
property of the porous medium and is independent of the nature of the
liquid or the potential field.
hydraulic conductivity ("K") is the same regardless of direction
low velocity flow with no mixing (i.e., no turbulence)
a stream or reach of a stream that is losing water to the subsurface
(also called an influent stream)
in reference to groundwater, withdrawals in excess of natural
replenishment and capture. Commonly applied to heavily pumped
areas in semiarid and arid regions, where opportunity for natural
replenishment and capture is small. The term is hydrologic and
excludes any connotation of unsatisfactory water-management practice
(see, however, overdraft).
(also called unsteady state-nonsteady shape) the condition when the
rate of flow through the aquifer is changing and water levels are
declining. It exists during the early stage of withdrawal when the
water level throughout die cone of depression is declining and the
shape of the cone is changing at a relatively rapid rate.
Glossary
4
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nonsteady state-steady
shape
optimum yield
overdraft
pellicular water
perched
permeability
permeameter
piezometer
porosity
poteiitiometric surface
recharge
recharge area
safe yield
saturated zone
is the condition that exists during the intermediate stage of withdrawals
when the water level is still declining but the shape of the central part
of the cone is essentially constant
the best use of groundwater that can be made under the circumstances;
a use dependent not only on hydrologic factors but also on legal,
social, and economic factors
withdrawals of groundwater at rates perceived to be excessive and,
therefore, an unsatisfactory water-management practice (see also
mining)
water adhering as films to the surfaces of openings and occurring as
wedge-shaped bodies at junctures of interstices in the zone of aeration
above the capillary fringe
unconfined groundwater separated from an underlying body of
groundwater by an unsaturated zone
the property of the aquifer allowing for transmission of fluid through
pores (i.e., connection of pores)
a laboratory device used to measure the intrinsic permeability and
hydraulic conductivity of a soil or rock sample
a nonpumping well, generally of small diameter, that is used to
measure the elevation of the water table or potentiometric surface. A
piezometer generally has a short well screen through which water can
enter.
the ratio of the volume of the interstices or voids in a rock or soil to
the total volume
imaginary saturated surface (potential head of confined aquifer); a
surface that represents the static head; the levels to which water will
rise in tightly cased wells
the processes of addition of water to the zone of saturation
an area in which water that is absorbed eventually reaches the zone of
saturation
magnitude of yield that can be relied upon over a long period of time
(similar to sustained yield)
zone in which all voids are filled with water (the water table is the
upper limit)
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5
Glossary
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slug-test
specific capacity
specific yield
steady-state
storage
storage coefficient "S"
storativity
sustained yield
transmissivity
vadose zone
an aquifer test made by either pouring a small instantaneous charge of
water into a well or by withdrawing a slug of water from the well
(when a slug of water is removed from the well, it is also called a
bail-down test)
the rate of discharge from a well divided by the drawdown in it. The
rate varies slowly with the duration of pumping, which should be
stated when known.
ratio of volume of water released under gravity to total volume of
saturated rock
the condition when the rate of flow is steady and water levels have
ceased to decline. It exists in the final stage of withdrawals when
neither the water level nor the shape of the cone is changing.
in groundwater hydrology, refers to 1) water naturally detained in a
groundwater reservoir, 2) artificial impoundment of water in
groundwater reservoirs, and 3) the water so impounded
volume of water taken into or released from aquifer storage per unit
surface area per unit change in head (dimensionless) (for confined,
S = 0.0001 to 0.001; for unconfmed, S = 0.2 to 0.3)
the volume of water an aquifer releases from or takes into storage per
unit surface area of the aquifer per unit change in head (also called
coefficient of storage)
continuous long-term groundwater production without progressive
storage depletion (see also safe yield)
the rate at which water is transmitted through a unit width of an
aquifer under a unit hydraulic gradient
the zone containing water under pressure less than that of the
atmosphere, including soil water, intermediate vadose water, and
capillary water. Some references include the capillary water in the
saturated zone. This zone is limited above by the land surface and
below by the surface of the zone of saturation (i.e., the water table).
Also called the unsaturated zone or zone of aeration. According to
Freeze and Cherry (1979):
1. It occurs above the water table and above the capillary fringe.
2. The soil pores are only partially filled with water; the moisture
content 6 is less than the porosity n.
3. The fluid pressure p is less than atmospheric; the pressure head \p
is less than zero.
4. The hydraulic head h must be measured with a tensiometer.
Glossary
6
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5. The hydraulic conductivity K and the moisture content 6 are both
functions of the pressure head \p.
water table surface of saturated zone area at atmospheric pressure; that surface in
an unconfined water body at which the pressure is atmospheric.
Defined by the levels at which water stands in wells that penetrate the
water body just far enough to hold standing water.
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Glossary
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Introduction to
Groundwater Investigations
(165.7)
Orientation and Introduction
Student Guide
-------
INTRODUCTION TO
GROUNDWATER
INVESTIGATIONS
(165.7)
Presented by:
Halliburton NUS Corporation
EPA Contract No. 68-C2-0121
Orientation and Introduction
Agenda:
• Emergency Response Training Program (ERTP) overview
Synopsis of ERTP courses
• Course layout and agenda
• Course materials
Facility information
Introduction to Groundwater kwwbgtftone
Orientation and Introduction
12/04
W
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Notes
Introduction to Grour^wstor Investigations 12/64
Orientation and Introduction page 3
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ERTP Overview
Comprehensive Environmental Response, Compensation
and Liability Act of 1980
(CERCLA)
Superfund Amendments and Reauthorization Act of 1986
(SARA)
U.S. Environmental Protection Agency
(EPA)
Environmental Response Training Program
(ERTP)
S-2
ERTP Overview
In 1980, the U.S. Congress passed the Comprehensive Environmental Response, Compensation and
Liability Act (CERCLA), also known as Superfund. In 1986, the Superfund Amendments and
Reauthorization Act (SARA) was passed. This act reauthorized CERCLA CERCLA provides for
liability, compensation, cleanup, and emergency response for hazardous substances released into the
environment and for the cleanup of inactive waste disposal sites. EPA allocated a portion of Superfund
money to training. EPA's Environmental Response Team (ERT) developed the Environmental Response
Training Program (ERTP) in response to the training needs of individuals involved in Superfund
activities.
Introduction to Groundwater Invwttpattona
Orientation and Introduction
12/94
page 4
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Notes
Introduction to GroundwHer Invwtigitions 12/94
Orientation and Introduction pa06 5
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ERTP Overview
U.S. Environmental Protection Agency
(EPA) |
Office of Solid Waste and Emergency Response
(OSWER)
Environmental Response Team
(ERT)
Environmental Response Training Program
(ERTP) |
S-3
ERTP Overview
ERTP is administered by ERT, which is part of OSWER. ERT offices and training facilities are located in
Cincinnati, Ohio, and Edison, New Jersey. ERT has contracted the development of ERTP courses to
Halliburton NUS Corporation (EPA Contract No. 68-C2-0121). The ERTP program provides education
and training for environmental employees at the federal, state, and local levels in all regions of the United
States. Training courses cover areas such as basic health and safety and more specialized topics such as
air sampling and treatment technologies.
Introduction to GroumJmfrr trweebgittone
OfientEbon and Introduction
12AM
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Notes
Introduction to Grouixiwtor In ^artflttiom 12/W
Ortentstion and Introduction 7
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Types of Credit Available
American Council on Education
• Upper-division baccalaureate degree (UDB): (1.0 Semester Hours).
ACE Requirements
100% attendance at this course.
>70% on the exam.
Contact the college/university to obtain information
on how to have ACE credit transferred.
Continuing Education Units
(1.9 CEUs)
CEU Requirements
100% attendance at this course.
>70% on the exam.
Introduction to Groundwater bwesbgebons
Orientation and Introduction
12/94
fw®
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Notes
Introduction to GrouinJw*tw tn»—tigationi 12/94
Oriontatton and Introduction page 0
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ERTP Courses
Health and Safety Courses
S-4 :>
• Hazardous Materials Incident Response Operations (165.5)
^ • Safety and Health Decision-Making for Managers (165.8)
• Emergency Response to Hazardous Material Incidents (165.15)
Technical Courses
S-5
• Treatment Technologies for Superfund (165.3)
• Air Monitoring for Hazardous Materials (165.4)
• Risk Assessment Guidance for Superfund (165.6)
• Introduction to Groundwater Investigations (165.7)
• Sampling for Hazardous Materials (165.9)
• Radiation Safety at Superfund Sites (165.11)
Special Courses
• Health and Safety Plan Workshop (165.12)
• Design of Air Impact Assessments at Hazardous Waste Sites (165.16)
• Removal Cost Management System (165.17)
• Inland Oil Spills (165.18)
Courses Offered in Conjunction with Other EPA Offices
S Chemical Emergency Preparedness and Prevention Office (CEPPO)
• Chemical Safety Audits (165.19)
^ Site Assessment Branch
• Preliminary Assessment
• Site Investigation
• Federal Facilities Preliminary Assessment/Site Investigation
• Hazard Ranking System
• Hazard Ranking System Documentation Record
S-6
S-7
S-8
Introduction to Growxhntw liMMgason*
OriwiMonand Introduction
12fc4
page 10
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Notes
Introduction to Grountfwtef Im^rtgrtom 12/94
Onentaflon and Introduction page 11
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Course Goals
• Identify the components of a groundwater system.
• List the primary hydrogeological factors to be considered in a site
investigation.
• Construct a flownet and calculate the hydraulic gradient at a site.
Discuss the use of geophysical survey methods.
Identify the different types of pumping tests and information obtained
from these tests.
Discuss drilling methods and installation of monitoring wells
Introduction to Groundwater InveeOgsbons
Orientation and Introduction
12/W
pagel2
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Notes
Introduction to Groundwater Investigation* 12/94
Orientation and Introduction pas* 13
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Course Layout and Agenda
Keypoints
• Agenda times are only approximate. Every effort is made to complete units, and to
finish the day, at the specified time.
• Classes begin promptly at 8:00 am. Please arrive on time to minimize distractions to
fellow students.
• Breaks are given between units.
• Lunch is 1 hour.
• Each student must take the examination given on Thursday.
• Direct participation in field or lab exercises is optional. Roles are randomly assigned
to ensure fairness.
Attendance at each lecture and exercise is required in order to receive a certificate.
Introduction Id Groundwater ImwSigaSons
Orientation and Introduction
12/84
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Notes
introduction to QrajinJ»ml* Irwwtigrtoni 12/94
Onontatton and Introduction pago 15
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Training Evaluation
• The Training Evaluation is a tool to collect valuable feedback from YOU
about this course.
• We value YOUR comments!! Important modifications have been made to
this course based on comments of previous students.
DO
DON'T
• Write in your comments at the end of
each unit!
Hold back!
Tell us if you feel the content of the
course manual is clear and complete!
Focus exclusively on the presentation
skills of the instructors.
Tell us if you feel the activities and
exercises were useful and helpful!
Write your name on the evaluation, if
it will inhibit you from being direct
and honest.
• Tell us if you feel the course will help
you perform related duties back on the
job!
Complete the first page at the end of
the course before you leave!
Write comments in ink.
Introduction to Ground*** Imesbgitions
Orientation and Introduction
12/94
pa9« 10
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Notes
Introduction to Groundwater tn"—f1gtion« 12^4
Orientation and Introduction page 17
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Please put beepers in the vibrate mode and
turn off radios. Be courteous to fellow
students and minimize distractions.
Emergency
Telephone
Numbers
Emergency Exits
Alarms
Sirens
12/94
pas*IS
-------
Notes
Introduction to Qrountfiw^li Irwertfltfona 12/94
Oriwrtaflon tnd Introduction page 19
.'lO
a
-------
GEOLOGY
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• Define the Doctrine of Uniformitarianism
• Describe the three basic rock types and evaluate each as
aquifers
• Describe the rock forming processes found on the Rock
Cycle diagram
• Identify the medium responsible for the erosion and transport
of sediments
• Describe the following depositional environments:
Alluvial fans
Braided streams
Meandering streams
Coastal (deltaic, interdeltaic, barrier island complexes)
Wind-blown deposits
Carbonates.
NOTE: Unless otherwise stated, the conditions for
performance are using all references and materials
provided in the course, and the standards of
performance are without error.
-------
GEOLOGY
MMR
MW 1
720 n
MW2
719.15 n
noH \ltl
717 ft
71825 fl
714.6 It
1/95
1
-------
NOTES
Doctrine
of
Uniformitarianism
"The Present is the
Key to the Past"
James Hutton, 1785
THE ROCK CYCLE
Deposition
Lithification
s/
\
Transport i
Sedimentary rocks
t
\
Weathering ^
Metamorphism
Igneous rocks
* Metamorphic rocks
\u
Melting
Geology
1/95
-------
NOTES
SEDIMENTATION
• Erosion processes (weathering)
• Transport agents
• Deposition
• Lithification
EROSION PROCESSES
• Wind
• Ice
• Water
• Biology
• Gravity
TRANSPORT AGENTS
• Wind
• Ice
• Water
• Biology
• Gravity
1/95
3
Geology j
/nM
/
-------
NOTES
DEPOSITION
• Wind
• Ice
• Water
• Gravity
LITHIFICATION
• Cementation
• Diagenesis
TYPES OF CEMENT
• Silica
• Iron oxides
• Kaolinite
• Montmorillonite
• lllite
• Calcite (aragonite)
Geology
4
1/95
-------
NOTES
SEDIMENTARY ROCKS
• Composed of particles of any rock type
- "Pores" form during deposition
• Most aquifers are sedimentary rocks
SEDIMENTARY ROCKS
Limestone
Shale
Sandstone
Coal
Dolomite
Siltstone
Conglomerate
Evaporite
METAMORPHISM
• Recrystallization
• "Earth's sweat'
1/95
5
Geology
-------
NOTES
METAMORPHIC ROCKS
PRESSURE
METAMORPHIC ROCKS
Marble Slate
Quartzite Phyllite
Gneiss Schist
" EARTH"S SWEAT"
Geology
6
1/95 i
-------
NOTES
MELTING/MAGMA
IGNEOUS ROCKS
Intrusive
e.g., granite
• Extrusive
e.g., basalt
IGNEOUS ROCKS
Gabbro Basalt
Granite Rhyolite
1/95
7
Geology
-------
NOTES
INTRUSIVE IGNEOUS
ROCK BODIES
iccolitl
Batholith ¦ I
Adapted from General Geology by Rob«rt Foit«r. 1968. p 63.
SEDIMENTARY ROCKS
• Composed of particles of any rock type
- "Pores" form during deposition
• Most aquifers are sedimentary rocks
ROCK TYPE
ENVIRONMENT
Conglomerate
Landslide, alluvial fan
Sandstone
Rivers, streams, beaches,
deltas, dunes, sand bars
Clay/shale
Lagoon, lake, flood plain,
deeper ocean
Limestone
Coral reef, atoll,
deeper ocean
Geology
8
1/95
, y ¦¦
-------
NOTES
CRITERIA TO DEFINE
DEPOSITIONAL
ENVIRONMENTS
LONGITUDINAL PROFILE
A Alluvial and landslide
B Braided stream
M Meandering stream
C Coastal
_ ys Stream hMdwatari
1 (length) >
A H (h^ht)
:: :::: USST
I:;::::::::::::;:-::::;::: M ^HuetuJ
-
1/95
9
Geology
u '
-------
NOTES
CRITERIA
• Longitudinal channel profile
• Median channel-grain size
• Sphericity/sorting
CRITERIA
* Penetration of stream
* Width-to-depth ratio
* Degree of sinuosity
LONGITUDINAL
CHANNEL PROFILE
Geology
10
1/95
-------
NOTES
LONGITUDINAL PROFILE
A Alluvial and landslide
B Braided stream
M Meandering stream
C Coastal
_ ^ Stream headwaters
* 1 (length) »
\ t
: a H(i»io«)
! Mouth of
R ' ¦ , %-f «tmam
M ::.::::::::7J?Soe#an|
STREAM GRADIENTS
High < > Low
: : A^s^^ ^
m r °^iij
MEDIAN
CHANNEL-GRAIN SIZE
1/95 11 Geology
-------
NOTES
MEDIAN CHANNEL-GRAIN SIZE
Large < » Small
Ocean
RELATIONSHIP OF STREAM VELOCITY
1000
o"
S 100
E
o
J 10
o
o
£ 1.0
0.1
Erosion
"
' Transportation X\ \ \;:
A \ Depos
i /\ . : i :
ition
Size 0.001 o.oi 0.1 1.0 10 100
(mm) Clay Silt Sand Gravel
SPHERICITY/SORTING
Geology
12
1/95
-------
NOTES
Angular <-
* Rounded
Ocean
SORTING
Poor <-
Well
™ Ocean
PENETRATION OF
STREAM
1/95
13
Geology
-------
NOTES
STREAM CHANNEL
Penetration
Shallc
>w <¦ » Deep
¦S J \J
... >~
: M
WIDTH-TO-DEPTH RATIO
STREAM CHANNEL
Width-to-Depth Ratio
High
rv^
i > Low
v / \J
a
::
::::::::::::::::::: M ::::::: ™Uc«n|
Geology
14
1/95
\\
V ,
-------
NOTES
DEGREE OF SINUOSITY
STREAM CHANNEL
Sinuosity
Oca an
DEPOSITIONS
ENVIRONMENTS
1/95
15
Geology
-------
NOTES
DEPOSITIONAL
ENVIRONMENTS
• Alluvial fan
• Braided stream
• Meandering stream
• Coastal deposits
• Wind-blown deposits
ALLUVIAL FAN
Geology
16
1/95
-------
NOTES
BRAIDED STREAM
1/95 17 Geology
V. ,
-------
NOTES
MEANDERING STREAM
COASTAL DEPOSITS
Geology
18
1/95
-------
NOTES
WIND-BLOWN DEPOSITS
1/95
19
-------
NOTES
CARBONATES
• Limestones
• Dolomites
EVAPORITES
• Carbonates
• Sulfates
• Chlorides
GLACIATION
Geology
20
1/95
-------
NOTES
GLACIERS/FREEZE-THAW
• Weathering and transport
• Large scale changes
• Poor to excellent sorting
(e.g., glacial till and outwash)
PROCESSES OF GLAC1AT1QN
• Erosion
• Transportation
• Deposition
1/95
21
Geology
-------
HYDROGEOLOGY
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to;
• Explain the hydrologic cycle and its relationship to rocks and
groundwater
• Differentiate between recharge and discharge areas
• Describe the relationship between porosity and permeability
• Describe the effect of porosity and permeability on
groundwater flow
• Define aquifer, aquitard, and aquiclude
• Compare confined aquifers and unconfined aquifers.
HQ2E; Unless otherwise stated, the conditions for
performance are using all references and materials
provided in the course, and the standards of
performance are without error.
-------
NOTES
HYDROGEOLOGY
HYDROGEOLOGY
The study of the interrelationships of
geologic materials and processes
with water, especially groundwater
1/95
Hydrogeology
-------
NOTES
EARTH'S WATER RESOURCES
• 80% oceans
• 19% groundwater
• 1 % ice
• 0.002% streams and lakes
• 0.0008% atmosphere
,
EARTH'S WATER USES
• Drinking
• Irrigation
• Fisheries
• Individual processes
• Transportation
• Waste disposal
HUMAN WATER CONTENT
• 45 - 75% by weight
• 65% average male
• 55% average female
Hydrogeobgy
2
-------
NOTES
Precipitation is a
beginning point for
the hydrologic cycle
HYDROLOGIC
CYCLE
Transpiration 1_
Precipitation
ivaporation
TsXAi^nunoff
Soil
moisture
DIRECT INFILTRATION
•r'/S.'
' 'Proclpttatioi
X Infiltration
1/95
3
Hydrogeology
-------
NOTES
CONTROLS ON INFILTRATION
• Soil moisture
• Compaction of soil
• Microstructures in the soil
• Vegetative cover
• Temperature
• Surface gradient
STREAM FLOW
V (VI
¦sv A :.(e "oas-sadtional
Q = Av
GAINING STREAM
Discharge = 8 cfs.
Discharge =10 cfs,
Hydrogeology 4 1^5 % ,¦»>
-------
NOTES
LOSING STREAM
Discharge = 10 cfs.
Discharge = 8
Vadose
zone
Ground surfaoe
¦\;Pore spaces partially'
r
Saturated
zone
4
//////////
Soil moisture
Groundwater
POROSITY
(n)
The volumetric ratio between the void
spaces (Vw) and total rock (V,):
n =11 ; n = s + sn
Vt
1/95
5
Hydrogeobgy
-------
NOTES
PRIMARY POROSITY
Refers to voids that were formed at
the same time the rock was formed
Sand Grain
Percent
Porosity
Total Volume - Volume Soil Particles w
X 100
Total Volume
SECONDARY POROSITY
Refers to voids that were formed
after the rock was formed
Hydrogeotogy
6
1/95
-------
NOTES
SECONDARY POROSITY
PERMEABILITY
The ease with which water will
move through a porous medium
POROSITY
so
&
m
§ so
<£
40
©
EL
Li-0
-Q
Sandstone
Clay
Sand Gravel
1/95
7
Hydrogeology
w
-------
NOTES
CONDUCTIVITY
1.000E+02
1.000E+01
i.oooe+oo
"I" 1.000E-01
-j| 1.000E-02
O, 1.000E-03
g 1.000E-0*
^ I.OOOE-OS
.§ lOOOE-OS
I 1.000E-07
l.oooE-o#
i.oooE-oe
1 000E-10
AQUIFER
A permeable geologic unit with the
ability to store, transmit, and
yield water in usable quantities
AQUITARD
A layer of low permeability that
can store and transmit groundwater
from one aquifer to another
Hydrogeobgy
8
1/95
-------
NOTES
AQUICLUDE
A confining layer with low
permeability that is essentially
impermeable
UNCONFINED AQUIFER
(Water Table)
A permeable geologic unit having the
ability to store, transmit, and yield
water in usable quantities
UNCONFINED AQUIFER
Watsr table
Unoonfinsd aquifer
"Confming unit"- aejuMri
vvvvWvvvvvvv
1/95
9
Hydrogeology
-------
NOTES
CONFINED AQUIFER
(Artesian)
An aquifer overlain by a confining layer
whose water is under sufficient pressure
to rise above the base of the confining
layer if it is perforated
CONFINED AQUIFER
Confining
unit
'*• aquttard
Pojertlometric
Confining unlt-aqultard
Recharge
Vadose zone
Water table
Confining layers
Hydrogeology
10
1/95
-------
NOTES
AQUIFERS AND AQUITARDS
Aqultard
Aquitard
POTENTIOMETRIC SURFACE
The elevation that water will rise to
in an opening (well) it the upper
confining layer of a confined
aquifer is perforated
TOTAL HEAD
(h.)
• Combination of elevation (z) and
pressure head (hp)
ht = z + hp
• Total head is the energy imparted to a
column of water
1/95
11
Hydrogeology
. !/
-------
NOTES
SPECIFIC RETENTION
(Sr)
The water in an aquifer that will not drain
by gravity and remains attached to the
aquifer media
SPECIFIC YIELD
(Sy)
The water in an aquifer that will
drain by gravity
Hydrogeology
VOID SPACE
(Porosity)
CT" '
12
1/95
-------
NOTES
SATURATION
WATER RETAINED AFTER GRAVITY
DRAINAGE
(Specific Retention)
HYDRAULIC CONDUCTIVITY
(K)
The volume of flow through a unit
cross section of an aquifer per unit
decline of head
1/95
13
Hydrogeology
-------
NOTES
HOMOGENEOUS
Hydraulic conductivity is not
dependent on position within a
geologic formation
HETEROGENEOUS
Hydraulic conductivity is dependent
on position within a geologic
formation
ISOTROPIC
Hydraulic conductivity is independent
of the direction of measurement at a
point in a geologic formation
Hydrogeology
14
1/95
-------
NOTES
ANISOTROPIC
Hydraulic conductivity varies with
the direction of measurement at a
point in a geologic formation
DARCY'S LAW
Q = KIA
• Q = discharge
• K = hydraulic conductivity
• I = hydraulic gradient
• A = area
DARCY'S LAW
• The flow rate through a porous material is
proportional to the head loss and inversely
proportional to the length of the flow path
• Valid for laminar flow
• Assume homogeneous and isotropic
conditions
1/95
15
Hydrogeology a ' <
-------
NOTES
tA |4 L- ~
* K Q ~ !
" -I
Gradient => H/L = I, the energy required to
move water the distance L
Q » quantity of flow(gpd)
A = crosa-aectionaJ area of flow(ft 2)
K ¦= hydraulic conductivity - gpd/ft
1
GROUNDWATER FLOW DIRECTION
* Underflow
Mixed
Baseflow
'Redrawn from On the relationship between river-basin geomorphology, aquifer hydraulics,and groundwater flow in
alluvial aquifers, Geologic Society of America Bulletin, v. 104, December 1992, with permission of Randall G. larkin.
Hydrogeology 16 i/95 ^
-------
NOTES
STREAM GRADIENTS
High < > Low
1
Channel Gradients in Alluvial Systems
0.0016
0X012
GW Flow Direction
¦ Underflow
0 Mixed
DBaseflow
QUnknown
2 0.0008
0X002
MIMHOMK2SC1 RQ HUM QUARK1 FT SP
Rivers
STREAM CHANNEL
Width-to-Depth Ratios
High «¦
¦» Low
icaan
'Redrawn from On the relationship between river-basin geomorphology, aquifer hydraulics,and groundwater flow in
alluvial aquifers. Geologic Society of America Bulletin, v. 104, December 1992, with permission of Randall G. Larkin.
1/95
17
Hydrogeology
-------
NOTES
Width-to-Depth Ratios in Alluvial Systems
2S0
O
« 200
s
r.
"5. 150
9
Q
£
¦a
100
§ $
1
GW Row Direction
H Underflow
0 Mixed
0 Baseflow
~ Unknown
ARK2MUM HO »CI OH Hit! Ml *RK1 FT (P
Rivers
STREAM CHANNEL
Width-to-Depth Ratios
High <-
J
-> Low
1
Stream Penetration in Alluvial Systems
100| :— . ,|
GW Flow Direction
¦ Underflow
~ Mixed
~ Baseflow
Rivers
'Redrawn from On the relationship between river-basin geomorphology, aquifer hydraulics,and groundwater flow in
alluvial aquifers, Geologic Society of America Bulletin, v, 104, December 1992, with permission of Randall G. Larkin.
Hydrogeology 18 1/95 . ; •
-------
NOTES
STREAM CHANNEL
SINUOSITY
Low <-
High
M :::::::: q ^Oow
SINUOSITY OF RIVER CHANNELS
GW Row Direction
H Undarflow
~ Mixed
CjBns»flow
0 Unknown
•P ARK1 OH HUM MO RQ ARK2 «Ci M1M
Rivers
MIAMI
iVER
A
-------
NOTES
ARKANSAS RIVER 1
BARRIER ISLAND
A
West Bay
Gulf of Mexico
'Redrawn from On the relationship between river-basin gaomorphology, aquifer hydraulics.and groundwater flow in
alluvial aquifers. Geologic Society of America Bulletin, v, 104, December 19S2, with permission of Randall G. Larkin,
Hydrogeobgy 20 1®5
V
-------
THE HYDROGEOLOGICAL
INVESTIGATION
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• Describe three types of hydrogeological investigations
• Given a list of seven elements involved in conducting a
hydrogeological investigation, describe the processes
involved in accomplishing each element
• List three pertinent questions that must be addressed when
investigating groundwater contamination.
NOTE: Unless otherwise stated, the conditions for
performance are using all references and materials
provided in the course, and the standards of
performance are without error.
-------
NOTES
THE HYDROGEOLOGICAL
INVESTIGATION
CONTAMINATION
f '|Leachate
Y #
Groundwater
REGIONAL INVESTIGATIONS
• Cover large areas (10-100 square
miles)
• Are used to
- Locate potential sources
- Determine regional geology
- Determine regional hydrology
1/95
1
The Hydrogeological Investigation ^
-------
NOTES
REGIONAL INVESTIGATIONS
* Include evaluation of
- General geology
- General hydrology
- Regional water quality
• Are not detailed studies
REGIONAL INVESTIGATION OF
COLBERT LANDFILL, SPOKANE, WA
Geology and hydrology
"...hydrogeologic conditions...
...dominated by...
...most recent glacial period..."
REGIONAL INVESTIGATION OF
COLBERT LANDFILL, SPOKANE, WA
Climate
"...values at site...are similar...
...to airport...
...because elevations are...
...similar."
The Hydrogeological Investigation
2
1/95
-------
NOTES
LOCAL INVESTIGATIONS
• Cover few square miles
• Are used to
- Define geology, hydrology,
geochemistry, and water quality
- Locate sources
LOCAL INVESTIGATIONS
• Include
- Topographic maps, geologic
maps, soils maps, well location
maps, and source locations
• Are more detailed studies
LOCAL INVESTIGATION OF
COLBERT LANDFILL, SPOKANE, WA
Hydrogeology
"...system...defined as containing
three aquifers and three aquitards."
1/95
3
The Hydrogeological Investigation
-------
NOTES
SITE INVESTIGATIONS
• Cover immediate area of site
• Are used to determine
- Site geology
- Site hydrology
- Contaminant migration controls
SITE INVESTIGATIONS
• Include
- Water level maps, geophysical
surveys, soil samples, water
samples, tank location maps,
tank inventories, and monitoring
wells
• Are most detailed (expensive) studies
CONDUCTING THE
INVESTIGATION
1. Establish objectives
2. Collect data
3. Conduct field investigation
4. Compile data
5. Interpret data
6. Develop conclusions
7. Present results
The Hydrogeological Investigation
4
1/95
-------
NOTES
ESTABLISH OBJECTIVES
• Detection
• Monitoring
• Site evaluation
• Selection of control methods
• Selection of treatment/remedial
methods
ESTABLISH THE OBJECTIVES
COLBERT LANDFILL, SPOKANE, WA
Focus
• Do affected residents have supplied
water?
• Is the landfill a continuing source?
• What are extent and processes for
offsite movement?
COLLECT DATA
Research Records
• Maps (soil, geologic, topographic,
county, and state)
• Aerial photographs
• Location of pumping centers (wells)
and discharge rates
• Stream discharge
1/95 5 The Hydrogeological Investigation
-------
NOTES
AERIAL PHOTOGRAPHY
• Historical photography
(1920 - present)
• Contract photography
(current site)
EPIC
Environmental Photographic
Interpretation Center
Western Region - EMSL/Las Vegas, Nevada
Eastern Region - EPA-EPIC/Warrenton, Virginia
USDA ASCS
(Agricultural Stabilization & Conservation Service)
Aerial Photography Field Office
Salt Lake City, Utah
(801) 525-5856
1945 - present
black & white
color infrared
The Hydrogeological Investigation
6
1/95
-------
NOTES
SANBORN FIRE
INSURANCE MAPS
• 1869 to 1950s
• Communities over 2000 population
• Updated periodically
• Locations of industries, pipelines,
storage vats, old dumps, and
wetlands
COLLECT DATA
Research Records
• Well logs
• Climatological data
• Chemical data
• Source or potential source location
COLLECT BACKGROUND DATA
COLBERT LANDFILL, SPOKANE, WA
Previous site use
"...electronics manufacturing...
...spent organic solvents...
...poured...down sides...
...hundred gallons a month."
1/95 7
The Hydrogeological Investigation
-------
NOTES
INFORMATION SOURCES
• U.S. Geological Survey
• State water commission
• State geological survey
• Departments of agriculture
INFORMATION SOURCES
• Soil Conservation Service
• Weather service
• Site records
• University research (theses, papers,
etc.)
CONDUCT FIELD INVESTIGATION
(After Record Search)
• Note topography
• Locate outcrops
• Note joint patterns
• Measure stream flow
• Measure stream temperature
• Note stream patterns
The Hydrogeological Investigation
8
1/95
-------
NOTES
CONDUCT FIELD INVESTIGATION
COLBERT LANDFILL, SPOKANE, WA
Monitoring wells
"...intended to complement...
...wells installed during...
...previous investigations..."
CONDUCT FIELD INVESTIGATION
(After Record Search)
• Note flora
• Locate springs and seeps
• Conduct geophysical survey
• Note soil characteristics
• Note rock type
• Install monitoring wells
CONDUCT FIELD INVESTIGATION
(After Record Search)
• Measure water levels
• Conduct aquifer tests
• Note aquifer thickness
• Note confining layers
• Determine hydrogeologic characteristics
• Determine limits (hydrologic, geologic, and
climatic)
1/95
9
The Hydrogeological Investigation
/T- \
-------
NOTES
CONDUCT FIELD INVESTIGATION
COLBERT LANDFILL, SPOKANE, WA
Soil characteristics
"...percolation tests indicate..
...surface runoff...
...occurs very infrequently..."
CONDUCT FIELD INVESTIGATION
(After Record Search)
• Conduct tracer studies
• Note hydraulic connections
• Collect samples
• Determine background water quality
• Identify types of contaminants
• Locate potential sources
• Determine types of aquifers involved
COMPILE DATA
• Prepare water level maps
• Prepare cross sections
• Plot potentiometric surface
• Determine contaminant mobility
characteristics
The Hydrogeological Investigation
10
1/95
-------
NOTES
COMPILE DATA
COLBERT LANDFILL, SPOKANE, WA
Contaminant mobility
• Moving with gravity - DNAPLs
• Solubilized in groundwater flow
• Volatilized in vadose - molecular diffusion
INTERPRET DATA
• Locate recharge areas
• Locate discharge areas
• Identify sources (responsible parties)
• Predict contaminant impact and fate
INTERPRET DATA
COLBERT LANDFILL, SPOKANE, WA
Identify responsible parties
"...'secondary' sources...
...may be major source...
...continued contamination..."
1/95
11
The Hydrogeologiced Investigation
-------
NOTES
DEVELOP CONCLUSIONS
• Is there a problem?
• How bad is it?
• Who is responsible?
• Can it be remediated?
• How?
PRESENT RESULTS
• Review of reports by others
(responsible parties, consultants, etc.)
• Formal report of investigation
• Hearings
• Public meetings
The Hydrogeologiccd Investigation
12
1/95
-------
CHECKLIST FOR A HYDROGEOLOGICAL INVESTIGATION
HAZARDOUS WASTE SITES INFORMATION LIST
When evaluating activities at sites where hazardous wastes may be causing or contributing to
groundwater contamination, it is important to gather as much information as possible. The
development of as much site information as possible can often provide valuable insight about site
history, waste disposal practices, regional and local geology and the potential for impacts to the
environment in the site vicinity.
In order to make your information gathering efforts easier, what follows is a list of the types of
questions which may be helpful to a site investigation. While these questions are oriented more
towards field activities, the questions also may prove to be helpful to those people responsible for
evaluating the adequacy of other site assessment documents.
Sources
National Water Well Association. 1991. Groundwater and Unsaturated Zone
Monitoring and Sampling. 45 pp. In: Practical Handbook of Groundwater
Monitoring.
U.S. EPA. 1986. RCRA Ground Water Monitoring Technical Enforcement
Guidance Document. 208 pp.
Stropes, D.F. 1987. Unpublished Research: Technical Review of Hazardous
Wastes Disposal Sites. 25 pp.
I. SITE/FACILITY HISTORY
A. Waste disposal history of the site.
1. Is this a material spill or other emergency response activity not at a Toxic
Substances Storage and Disposal Facility (TSSDF) ?
2. What hazardous wastes are being manufactured, stored, treated or disposed
of at the site?
3. For active manufacturing operations, what industrial processes are being used
and what raw materials are used in the industrial processes?
4. Are the raw materials altered or transformed in any way during industrial
processes to result in waste materials which are different from the raw
materials?
5. How long has the facility been in operation?
1195 13 The Hydro geological Investigation
-------
6. Have the types of hazardous wastes manufactured, stored, treated or disposed
of at the site changed during the history of the site?
7. Have the industrial processes used at the site changed over the history of the
site?
8. If the industrial processes are different, what previous industrial processes
were used in the past, how long, and what types of wastes were end products
of the processes.
9. What environmental media (air, land, water) have been or are being affected
by the facility/site activities?
10. What is the form of the site wastes (sludge, slurry, liquid, powder,
containerized, bulk storage)?
11. How much waste is generated or disposed of at the location daily?
12. What is the history of above and underground storage tank use at the site?
13. What types of regulated manufacturing or pollution control units exist at the
facility?
14. What governmental agencies are responsible for the regulated units?
15. Do any historical records about the site exist? If so, where are these records?
16. Has a check of any existing historical maps or aerial photos been done to
provide further insight as to past site activities?
17. Is there any history of groundwater contamination as a result of the site
activities?
B. Details of the site disposal activities.
1. Are the site disposal units currently in compliance with all applicable rules,
regulations and standards?
2. Are disposal areas isolated from the subsurface by the use of liners,
impermeable material, etc.?
3. What type of isolating material is in use?
4. Are multiple isolation systems in use?
5. Is a leachate/contaminant collection system in use?
The Hydrogeological Investigation
14
1/95
-------
6. Are any monitoring wells installed adjacent to the disposal/collection system
units?
7. Is there a surface water run-off control system?
8. Are any parts of the site/facility capped with an impermeable cover material?
9. What is the condition of the cap?
10. Are areas of previous wastes disposal well defined?
C. What is the nature of groundwater usage from aquifers beneath the site or in adjacent
areas?
1. Do any water supply wells exist in the aquifers beneath the site and adjacent
areas?
2. Are water supply wells used for potable water supplies or for industrial
process water?
3. Is the groundwater treated prior to use?
4. What are the water supply wells' pumpage rates? Daily? Monthly?
Annually?
5. What are the depths of the wells' screened intervals?
6. What other well drilling, well construction or well completion information is
available?
7. Do subsurface geologic well logs exist for the wells?
8. Are the wells up gradient, at, or down gradient of the site/facility?
9. Does pumping from these wells modify the regional groundwater table or
potentiometric surface?
II. HYDROGEOLOGIC CHARACTERIZATION
A. Has the purpose of the hydrogeologic investigation been clearly and adequately
defined?
1. Characterize the hydrogeologic system at the site.
1/95
15 The Hydro geological Investigation
"is,-
w; v/'
-------
2. Determine whether there has been downgradient degradation of water quality
from a potential source of contamination.
3. Determine the upgradient source of contamination at a known downgradient
contamination receptor (well, spring, or surface water body).
B. Has the site location and all major site features been shown on a map?
1. Has the site been located on a state map?
2. Has the site been located on a USGS 7-1/2 minute topographic quadrangle
map published at a scale of 1:25,000?
3. Have coordinates for further site identification (latitude, longitude, degrees,
minutes, seconds, or a site specific grid system) been provided?
C. Has a base map of the site been prepared?
1. What is the map source?
2. Are air photos available?
3. Are all components of a map (north arrow, scale, map legend) shown and
defined on the base map?
4. Does the map show elevations and contours?
5. Is the scale of the map adequate to delineate on-site features' dimensions
adequately?
6. Does the map show features adjacent to the site which may be pertinent to the
hydrogeologic investigation?
7. Are all natural physical features (topography, surface waters, surface water
flow divides, etc.) shown on the map?
D. Has the subsurface geology been identified?
1. Is the geologic interpretation based on soil borings and well drilling logs?
2. Have any other reference materials been used?
3. Are aquifers present beneath the site?
4. Is the first aquifer encountered confined or unconfined?
5. Are all aquifers and confining units continuous across the site?
The Hydrogeological Investigation 16
1/95 2
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6. Have all geologic strata been described (thickness, rock type,
unconsolidated/consolidated materials, depth, etc.)?
7. Do multiple aquifers exist at the site?
8. Have any porous versus fractured flow media been described?
E. Do the driller's logs of the deepest borings at each well cluster show that soil
material samples were collected at five foot intervals? If not at what intervals were
samples taken?
1. Is there a stratigraphic log of the deepest boreholes?
2. Were the borings extended to a depth below any confining beds beneath the
shallowest aquifer?
3. Have enough borings of the area been done to adequately define the
continuity and thickness of any confining beds?
4. Have all logs been prepared by a qualified geologist, soil scientist or engineer
using a standardized classification system?
5. Were any laboratory tests conducted on the soil and soil material samples?
What types of tests were performed?
6. Were grain size distributions used to determine the size of the gravel pack or
sand filter placed in the annular space opposite the well screen?
F. Have field and/or laboratory permeability tests been performed to identify variations
in aquifer and confining bed properties?
1. What type(s) of tests were performed?
2. What was the range of hydraulic conductivity values found in the aquifer?
What was the arithmetic mean value?
3. What was the range of hydraulic conductivity values found in the confining
bed? What was the arithmetic mean value?
4. Where are the most permeable subsurface zones located relative to the waste
disposal facility?
5. Have geologic cross-sections been constructed?
G. Have field and/or laboratory tests been performed to determine the specific yield,
storativity or effective porosity of the aquifer?
1/95
17
The Hydrogeological Investigation "J
V' v*
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1. What type(s) of tests were performed?
2. What is the range of specific yield, storativity or effective porosity values?
3. What are the average values?
H. Has the horizontal groundwater flow direction been determined?
1. Have a minimum of three piezometers been installed to determine the
direction of flow in the aquifer?
2. Do any water-level readings show local variations of the water table caused
by mounds or sinks?
3. Do any identified mounds or sinks result in alterations of the regional or local
horizontal groundwater direction of flow?
4. Do any surface features which may have an effect on the horizontal flow
exist?
5. Have all piezometer installations in the uppermost aquifer been screened at ,
approximately the same depth below the water table?
6. Do any discernible seasonal variations in water levels exist?
7. Do any short term variations in water levels exist? If so what possible causes
may explain these variations?
I. Has the magnitude of the horizontal hydraulic gradient been determined at various
locations across the site?
1. What is the average horizontal hydraulic gradient at the site?
2. Where is the horizontal hydraulic gradient the steepest?
3. Does this location correlate to a known area of lower hydraulic conductivity
in the aquifer?
4. Does this location correlate to a known area of lower aquifer thickness?
5. Where is the horizontal hydraulic gradient the lowest (flat)?
6. Does this location correlate to a known area of greater hydraulic conductivity
in the aquifer?
7. Does this location correlate to a known area of greater aquifer thickness?
The Hydrogeobgical Investigation
18
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J. If multiple aquifers exist, have wells been installed in each aquifer to determine the
vertical component of groundwater flow?
1. Have the wells in each aquifer been installed in a single borehole or in
separate boreholes?
2. If a single borehole was used, what tests were conducted to assure that no
leakage between the upper and lower aquifers exist?
3. If a single borehole was used, what well installation, construction and
development techniques were used to assure that no leakage between the
upper and lower aquifers exist?
4. Based on the difference in hydraulic head between upper and lower aquifers
can the site be described as:
a. predominantly a recharge area?
b. predominantly a discharge area?
c. predominantly an area of horizontal flow?
5. If recharge, discharge or horizontal flow areas exist, have these locations
been shown on a hydrogeologic map (including supporting cross-sections) of
the site?
K. Has the magnitude of the vertical hydraulic gradients been determined at various
locations across the site?
1. What is the average vertical hydraulic gradient at the site?
2. Where is the vertical hydraulic gradient the steepest?
3. Can this location be correlated to any known areas of lower hydraulic
conductivity?
4. Where is the vertical hydraulic gradient the flattest?
5. Based upon the vertical hydraulic gradient, what relationship exists between
the shallow and deeper aquifers?
6. Is there any regional or off-site vertical hydraulic gradient information which
may support or conflict with the site's vertical hydraulic gradient data?
L. Determination of seepage velocities and travel times.
1. What is the average seepage velocity of water moving from the waste facility
to the downgradient site boundary?
1/95
19
The Hydrogeological Investigation
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2. What is the average travel time of water to move from the waste facility to
the nearest downgradient monitoring wells?
3. What is the basis for the seepage velocity and travel time determinations?
M. Have potentiometric maps, flow nets, geologic maps and cross-sections been prepared
for the purpose of showing the direction of groundwater flow at the site?
Horizontal Flow Components (plan view)
1. Do the contours and contour intervals between the equipotential lines
adequately describe the flow regime?
Suggested Contour Intervals:
a. 0.1 to 0.5 feet if the horizontal flow component is relatively flat.
b. 0.5 to 1.0 feet if the horizontal flow component is moderately steep.
c. 1.0 to 5.0 feet if the horizontal flow component is extremely steep.
2. Have the equipotential lines been accurately drawn?
a. With respect to the elevations of water levels in the wells or
piezometers?
b. With respect to nearby or on-site rivers, lakes, wells or other
boundary conditions?
c. With respect to other naturally occurring or manmade physical
features that might cause groundwater mounds or sinks in the area?
d. Do variations in the spacing of equipotential lines correspond to
known areas with relative transmissivity variations?
3. Do the constructed groundwater-flow lines cross equipotential lines at right
angles?
4. Can conclusions about the aquifer(s) relative homogeneity and isotropy be
made based on variations in the flow lines?
Vertical Flow Components (cross-sections)
1. Is the transect for the vertical flow component cross-section(s) laid out along
the line of a groundwater flow path as seen in the plan view?
2. Is the variation in land-surface topography accurately represented on the
cross-section(s)?
The Hydrogeological Investigation 20 i/95
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3. Have both vertical and horizontal scales been provided?
4. What differences exist between the vertical and horizontal scales?
5. Are all monitoring wells, piezometers, and screened intervals accurately
shown?
N. What is the site water quality and geochemistry?
1. What are the upgradient-groundwater quality conditions?
2. What are the downgradient-groundwater quality conditions?
3. What water-quality parameters have been determined downhole?
4. What water-quality parameters have been determined at the well head?
5. Have all appropriate field water-quality determinations, equipment used and
procedures been followed?
6. Does an adequate QA7QC procedure exist?
7. What if any, relationship exists between the site water-quality conditions and
the past and/or present activities at the site?
DETECTION MONITORING SYSTEM
A. Are the facility upgradient and downgradient monitoring wells properly located to
detect any water-quality degradation from the waste source(s)?
Horizontal Flow
1. Will groundwater from the upgradient well locations flow through or under
the waste source in an unconfined aquifer?
2. Will groundwater from the upgradient well locations flow beneath the waste
source and under an overlying confining bed in a confined aquifer?
3. Will groundwater from the upgradient well locations flow beneath the waste
source in an unconfined aquifer separated from the waste source by an
impervious liner?
4. Will groundwater from the waste-source area flow toward downgradient
wells?
21
The Hydro geological Investigation
-------
Vertical Flow
1. Are the monitoring wells correctly screened to intercept a possible
contaminant plume from the waste source based on an accurate interpretation
of the vertical flow regime (recharge area, discharge area, or area of
horizontal flow)?
B. Are the monitoring wells located adequately to provide sufficient groundwater- flow
information?
1. Are regional water levels unaffected by local groundwater mounds or sinks?
2. Are additional monitoring wells located to provide water-level information
from local groundwater mounds or sinks?
3. Do upgradient and downgradient monitoring wells provide representative
samples?
C. Monitoring Well Construction
1. Were precautions taken during the drilling of the borehole and installation of
the well to prevent introduction of contaminants into the well?
2. Is the well casing and screen material inert to the probable major
contaminants of interest?
3. What type of well casing and screen material was used?
4. Does the casing and screen material manufacturer have any available
information about possible leaching of contaminants from the casing and
screen material?
5. How are the well casing and screen segments connected?
6. If cement or glue has been used what is the potential for contaminants to
leach into the groundwater?
7. Were all downhole well components steam cleaned prior to installation?
8. If another cleaning technique was used, what materials were used?
D. Are there as built drawings or details of each monitoring well nest or cluster showing
depth of well, screen intervals, type and size of screen, length of screen and riser,
filter packs, seals, protective casings, etc.?
1. Do the figures show design details of as built wells as opposed to details of
proposed wells?
The Hydro geological Investigation
22
1/95
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2. Are the well depth(s) and diameter(s) shown?
3. Are the screened intervals and type and size of screen openings shown?
4. Is the length of the screen shown?
5. Is the length of the riser pipe and stick-up above the land surface shown?
6. Is the filter pack around the screened interval shown?
7. Does the filter pack extend at least one foot above and below the screened
intervals?
8. What type of sealant was placed in the annulus above the filter pack?
9. What is the thickness of the seal?
10. How was the seal put in place?
11. Will a protective casing or reinforced posts be necessary to protect the
monitoring well from damage?
12. Is any manufacturer's information available to verify that all materials used
in the well construction do not represent potential sources of water
contamination?
13. Have samples of well construction materials used been kept for future
analysis to verify that the materials do not represent sources of water
contamination?
Are the screened intervals appropriate to the geologic setting and the sampling of a
potential problem?
1. Is the screen set opposite a stratigraphic layer with relatively high hydraulic
conductivity?
2. Is the screened interval set sufficiently below the water table so that water-
level measurements can be taken and water samples can be collected during
periods of low water level?
3. Is the screened interval placed in the aquifer(s) of concern?
4. If a single long screen was installed over the entire saturated thickness of the
aquifer, what effect will this have on analytical data from this monitoring
well?
5. Has the entire aquifer thickness been penetrated and screened?
23 The Hydrogeological Investigation
-------
6. Have piezometers been installed to determine vertical and horizontal flow
directions?
7. Is the base of the waste disposal unit above the seasonal high water table?
8. What is the thickness of the unsaturated zone between the base of the waste
disposal unit and the seasonal high water table?
F. Has a professional survey been conducted to determine the elevation and location of
the measuring point at each well with reference to a common datum?
1. Is the survey at each monitoring well accurate to ±0.01 feet?
2. Is each surveyed measuring point located at the top of the well casing?
3. What benchmark was used as a starting point for the survey?
4. Are the elevations of the measuring point at each well referenced to mean sea
level and not some local datum?
G. Has an adequate sampling and analysis program been written for the site?
1. Are the major contaminants inorganic compounds?
2. Will field filtering and preservation be done in the field?
3. Are the major contaminants organic coumpounds?
4. Where would you expect to find the contaminants in the aquifer?
a. Floating at the top of the aquifer (LNAPLs)?
b. Dissolved in the groundwater and flowing with it?
c. Concentrated at the bottom of the aquifer (DNAPLs)?
5. What are the possible degradation end products of the original organic
contaminants?
6. Is the sampling method adequate to prevent any loss of volatile constituents?
7. Are field measurements such as pH, Eh, specific conductance, dissolved
oxygen and temperature taken in the field?
8. Does a generic sampling and analysis protocol exist?
9. Does the sampling and analysis protocol address sample preservation, storage,
transport, container identification and chain of custody procedures?
The Hydrogeologiccd Investigation 24 i/05
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10. Is the analysis laboratory certified by EPA for the analyses to be performed?
11. Did the laboratory provide input to the sampling and analysis program?
12. Is the sampling and analysis program written, clear, concise, understandable
and site specific?
Has a QA/QC plan been written for the groundwater monitoring program?
Water-Level Measurements
1. Have worksheets containing relevant fixed data, some of which are indicated
below, been prepared for use by the person taking water-level readings?
a. Well identification number?
b. Location of measuring point of each well?
c. Elevation of measuring point at each well relative to mean sea level?
d. Elevations of screened interval at each well?
e. Type of measuring instrument to be used?
2. Do the worksheets for use by the person taking water-level readings have
columns for computation of:
a. Depth to the water table?
b. Measuring point data to be added to or subtracted from readings of
measuring instrument?
c. Adjusted depth to water surface?
d. Conversion of depth to water surface?
3. Do the worksheets have a space for pertinent comments?
Sample Collection
1. Are well purging procedures prior to sampling described as written
procedures?
2. Is the method of purging specified?
3. Is the sample collection technique specified?
4. Is the sample storage vessel described?
25 The Hydrogeological Investigation
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5. Is the sample volume specified?
6. Is the sample identification system described?
7. Are there provisions for:
a. Trip blanks?
b. Spiked samples?
c. Duplicate, replicate or blind samples?
8. Is the sampling frequency specified?
Sample Analysis
1. Does the laboratory have a QA/QC program for all samples?
2. Is the QA/QC program written?
3. Does the laboratory provide information on the accuracy and precision of the
analytical results?
4. Did the laboratory participate in the development of the sampling and analysis
plan for the groundwater monitoring program and the QA/QC plan for the
non-laboratory portion of the sampling program?
I. Is the QA/QC plan being followed during implementation of the sampling and
analysis program?
1. Is the same consultant who prepared the QA/QC plan responsible for its
implementation?
2. How many copies are there of the QA/QC plan?
3. Who has copies and where are they located?
4. Does the field person taking water-level measurements and collecting samples
have a copy?
5. Does the field person understand the importance of following the QA/QC
plan explicitly each time?
6. What safeguards and checks are there to assure there will be no deviation
from the QA/QC plan in the field and the laboratory?
J. If any more field work or data will be necessary to meet the objectives of the
hydrogeologic investigation, what types of additional field installations and data will
be needed?
The Hydrogeological Investigation
26
1/95
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GEOPHYSICAL METHODS
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• Describe the five geophysical techniques listed below:
1. Magnetics
2. Electromagnetics (EM)
3. Electrical resistivity
4. Seismic refraction
5. Ground-penetrating radar
• List the physical properties measured by the five geophysical
techniques
• Identify interferences for each the geophysical technique
• Explain the need for geological control when making
geophysical interpretations.
NOTE: Unless otherwise stated, the conditions for
performance are using all references and materials
provided in the course, and the standards of
performance are without error.
-------
NOTES
GEOPHYSICAL METHODS
GEOPHYSICS
• Nonintrusive, investigative tool
• Methods are site specific
• Data must be "ground truthed"
• Professional interpretation necessary
RELATIVE SITE COVERAGE
/o
/ i i
K
i i
i i
^ ' v
*¦* — —
i
l
Jn
s
Volume of typical Volume of drilling
geophysical measurement or water sampling
1/95
1
Geophysical Methods
-------
NOTES
"GROUND TRUTHING"
Correlation of physical evidence
(i.e., rock cores) to geophysical
data
ANOMALY
Significant variation from background
GEOPHYSICAL TECHNIQUES
• Magnetics
• Electromagnetics (EM)
• Electrical resistivity
• Seismic refraction
• Ground-penetrating radar
• Borehole geophysics
Geophysical Methods
2
1/95
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NOTES
MAGNETICS
• Measurement of magnetic field strength
in units of gammas
• Anomalies in magnetic field strength are
primarily caused by variations in
concentrations of ferromagnetic
materials in the vicinity of the sensor
MAGNETICS
Advantages
• Relatively low cost (cost-effective)
• Short time frame required
• Little, if any, site preparation needed
• Simple survey sufficient (Brunton)
MAGNETICS
Disadvantages
• Cultural noise limitations
• Difficulty in differentiating between steel
objects
1/95
3
Geophysical Methods
-------
ELECTROMAGNETICS
• Based on physical principles of inducing
and detecting electrical flow within
geologic strata
• Measures bulk conductivity (the inverse
of resistivity) of geologic materials
beneath the transmitter and receiver coils
• Currents are induced by application of
time-varying magnetic fields
ELECTROMAGNETICS
Advantages
• Rapid data collection with minimum
personnel
• Lightweight, portable equipment
• Commonly used in groundwater pollution
investigations
ELECTROMAGNETICS
Disadvantages
• Cultural noise limitations
• Limitations in areas where geology varies
laterally (anomalies can be misinterpreted
as plumes)
4
1/95
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NOTES
ELECTRICAL RESISTIVITY
• Measures the bulk resistivity of the
subsurface in ohm-meters
• Current is injected into the ground
through surface electrodes
ELECTRICAL RESISTIVITIES OF
GEOLOGIC MATERIALS
Function of:
• Porosity
• Permeability
• Water saturation
• Concentration of dissolved solids in
pore fluids
ELECTRICAL RESISTIVITY
Advantages
• Qualitative modeling is possible
• Models can be used to estimate depths,
thicknesses, and resistivities of
subsurface layers
• Layer resistivities can be used to estimate
resistivity of saturating fluid
1/95
5
Geophysical Methods
-------
NOTES
ELECTRICAL RESISTIVITY
Disadvantages
• Cultural noise limitations
• Large area free from grounded metallic
structures required
• Labor intensive (2-3 person crew)
SEISMIC TECHNIQUES
• Seismic refraction
• Seismic reflection
SEISMIC REFRACTION
• Measures travel time of acoustic wave
refracted along an interface
• Most commonly used at sites where
bedrock is less than 500 feet below
ground surface
Geophysical Methods
6
1/95
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NOTES
SEISMIC REFRACTION
Advantages
• Can determine layer velocities
• Can calculate estimates of depths to
different interfaces
• Can obtain subsurface information
between boreholes
• Can determine depth to water table
SEISMIC REFRACTION
Assumptions
• Velocities of layers increase with depth
• Velocity contrast between layers is
sufficient to resolve interface
• Geometry of geophones in relation to
refracting layers will permit detection of
thin layers
SEISMIC REFRACTION
Disadvantages
• Assumptions must be made
• Assumptions must be valid
1/95
7
Geophysical Methods
-------
NOTES
SEISMIC REFLECTION
• Measures travel time of acoustic wave
reflected along an interface
• Precise depth determination cannot be
made without other methods
• Magnitude of energy required is limiting
factor
GROUND-PENETRATING RADAR
A transmitter emits pulses of
high-frequency electromagnetic waves
into the subsurface which are scattered
back to the receiving antenna on the
surface and recorded as a function of
time
GROUND-PENETRATING RADAR
• Depth penetration is severely limited by
attenuation of electromagnetic waves into
the ground
• Attenuating factors
- Shallow water table
- Increase in clay content in the
subsurface
- Electrical resistivity less than
30 ohm-meters
Geophysical Methods
8
1/95
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NOTES
GROUND-PENETRATING RADAR
Advantages
• Continuous display of data
• High resolution data under favorable site
conditions
• Real-time site evaluation possible
GROUND-PENETRATING RADAR
Disadvantages
• Limitations of site-specific nature of
technique
• Site preparation necessary for survey
BOREHOLE GEOPHYSICS
1/95
9
Geophysical Methods
V
-------
NOTES
Qaoloflie
Nautran
•and
fam day
lay art
(frath waiar)
Mnu rocK'
IMS
tanditona
SH layara
(brackish
watar)
•hala
faw SS
lay art
Comparison of electric and
radioactive borehole logs
BOREHOLE GEOPHYSICS
• Spontaneous potential
• Normal resistivity
• Natural-gamma
• Gamma-gamma
Geophysical Methods
10
-------
NOTES
BOREHOLE GEOPHYSICS
• Neutron
• Caliper
• Acoustic
• Temperature
SPONTANEOUS POTENTIAL
• Records natural potential between
borehole fluid and surrounding materials
• Mainly used for geologic correlation,
determining bed thickness, and separating
nonporous from porous rocks
(i.e., shale-sandstone, shale-carbonate)
• Can only be run in open, fluid-filled
boreholes
RESISTIVITY
• Measures apparent resistivity of a volume
of rock/soil surrounding the borehole
• Radius of investigation is generally equal to
the distance between the borehole current
and measuring electrodes
• Can only be run in open, fluid-filled
boreholes
1/95
11
Geophysical Methods v
-------
NOTES
GAMMA
• Measures the amount of natural-gamma
radiation emitted by rocks/soils
• Main use is for identification of lithology
and stratigraphic correlation
• Can be run in open or cased and fluid- or
air-filled boreholes
GAMMA-GAMMA
• Measures the intensity of gamma
radiation from a source in the probe
after it is backscattered and attenuated
in the rock/soils surrounding the borehole
• Main use is for identification of lithology
and measurement of bulk density and
porosity of rocks/soils
• Can be run in open or cased and fluid- or
air-filled boreholes
NEUTRON
• Measures moisture content in the vadose
zone and total porosity in sediments and
rocks
• Neutron sources and detector are
arranged in logging device so that output
is mainly a function of water within the
borehole walls
• Can be run in open or cased and fluid- or
air-filled boreholes
Geophysical Methods
12
1/95
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NOTES
CALIPER
• Records borehole diameter and provides
information on fracturing, bedding plane
partings, or openings that may affect
fluid transport
• Can be run in open or cased and fluid- or
air-filled boreholes
ACOUSTIC
• A record of the transit time of an
acoustic pulse emitted and received by
the logging tool
• Response is indicative of porosity and
fracturing in sediments or rocks
• Can be run in open or cased, fluid-filled
boreholes
TEMPERATURE
• A continuous record of the temperature
of the environment immediately
surrounding the borehole
• Information can be obtained on the
source and movement of water and the
thermal conductivity of rocks
• Can be run in open or cased, fluid-filled
boreholes
1/95
13
Geophysical Methods
\ ",V-
-------
MONITORING THE
VADOSE ZONE
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• Describe the vadose zone
• List three reasons why the vadose zone is important in
groundwater investigations
• Describe the principles of soil gas wells
• Describe the operation of pressure vacuum lysimeters
• Characterize the limitations of soil gas wells
• Characterize the limitations of vacuum lysimeters.
NOTE: Unless otherwise stated, the conditions for
performance are using all references and materials
provided in the course, and the standards of
performance are without error.
-------
NOTES
MONITORING THE
VADOSE ZONE
THE VADOSE ZONE
Consists of:
• Soils and particulate material
• Vapors in pore spaces
• Liquids on grain surfaces
Vadose
zone
Ground surface
Soil moisture
\^Pore spaces partially -
flUed with water
»"tV* 'V. * f:1»i ~*: t •'!
Saturated
zone
i
. Groundwater
;/95 1 Monitoring the Vadose Zone
-------
NOTES
PHYSICAL PROPERTIES
Vadose Zone
• Organic matter
• Lithology/stratigraphy
• Thickness
• Grain size distribution
PHYSICAL PROPERTIES
Vadose Zone
• Water content
• Soil density
• Specific yield
• Specific retention
CHEMICAL CHARACTERISTICS
Vadose Zone
• Soil vapors/gases
• Pore water
Monitoring the Vadose Zone
2
1/95 '
\
-------
NOTES
WATER QUALITY
Common Parameters
• Temperature
• pH
• Conductivity
• Chemical analysis
THE VADOSE ZONE
Consists of:
• Soils and particulate material
• Vapors in pore spaces
• Liquids on grain surfaces
TENSIOMETER
• Measures the capillary pressure in soil
• Advantages
- Inexpensive
- Durable
- Easy to operate
1/95
3
Monitoring the Vadose Zone
-------
NOTES
TENSIOMETER
• Disadvantages
- Ineffective under very dry
conditions because of air entry
- Sensitive to temperature changes
- Sensitive to atmospheric pressure
changes
- Sensitive to air bubbles in lines
- Requires a long time to achieve
equilibrium
ELECTRICAL
RESISTANCE BLOCKS
c
1
| Current source
4->
Water
«-~
Water
v. Field calibration
content
Resi«ta/ice
ELECTRICAL
RESISTANCE BLOCK
• Measures moisture content in soil
• Advantages
- Suited for general use
- Inexpensive
- Can determine suction or moisture
content
- Requires little maintenance
Monitoring the Vadose Zone 4
-------
NOTES
ELECTRICAL
RESISTANCE BLOCK
• Disadvantages
- Ineffective under very dry
conditions
- Sensitive to temperature
- Calibration is time-consuming
- Affected by salinity
NEUTRON MOISTURE LOGGING
Detector
• Neutrons from source are slowed down by
hydrogen cloud
• Hydrogen sources are water and
contaminants
NEUTRON
MOISTURE LOGGING
• Interacts with hydrogen in water
• Advantages
- Readings directly related to soil
moisture
- Moisture content can be measured
regardless of physical state
1/95
5
Monitoring the Vadose Zone
-------
NOTES
NEUTRON
MOISTURE LOGGING
• Disadvantages
- Expensive
- No information on soil-water
pressure
- No information on changes in
density
- Not accurate for small changes
- Requires care in handling source
- Requires license to use instrument
GAMMA-RAY ATTENUATION
Detector
• Changes in attenuation indicate
differences in moisture content
GAMMA-RAY ATTENUATION
• Determines soil density
• Advantages
- Can measure wetting front within
2 cm
Monitoring the Vadose Zone
6
1/95
-------
GAMMA-RAY ATTENUATION
• Disadvantages
- Expensive
- Radioactive source requires
special care
- Changes in bulk density affect
calibration (e.g., swelling and
frost heave)
NOTES
PSYCHROMETER
• Measures relative humidity of soil
water
• Advantages
- Measures capillary pressure
under very dry conditions
PSYCHROMETER
• Disadvantages
- Very sensitive to temperature
fluctuations
- Expensive
- Complex
- Performs poorly in wet media
;/95 7 Monitoring the Vadose Zone
X
-------
NOTES
FLOW RATES
• Infiltrometers (constant head)
• Test basins (falling head)
• Water budgets (hydrologic cycle)
• Tracer studies
- Dyes
- Radioactive isotopes
- Selected ions
• Problem:
Water is held under tension in
the vadose zone and will not
flow into wells
• Solution:
Create an area of lower potential
to induce flow into a sampling
device
LYSIMETER
A device for sampling interstitial
moisture in the unsaturated zone
Monitoring the Vadose Zone
8
1/95
-------
NOTES
LYSIMETER INSTALLATION
Scraanwi
riot Km
•oil
Tubing
lys(m«t»r
SerMrwd
n«iw«
toil
i Silica flour
i B»ntonite
EVACUATION OF LYSIMETER
Closed valve i
Suction pump
Negative
' pressure
EVACUATION OF LYSIMETER
1/95
9
Monitoring the Vadose Zone
-------
NOTES
TRANSFER TO SAMPLE BOTTLE
Poaitiva
pr»S9ur*
SAMPLE VOLUME
a
c
3, 1-
to
Irrigated sits Dry conditions
SOIL GAS SURVEYS
m
SOURCE
0
m
m
?
m
Monitoring the Vadose Zone
10
1/95
-------
NOTES
SOIL GAS WELL
Schematic
Seal
Vadose
Well
zone
Soil gas
SOIL GAS SURVEYS
XXX
X
X
X
X
XXX
X
X
X
SOURCE
+
1
X
XXX
X X X X
+ + +
SOIL GAS SURVEYS
X X X X X X X
X
1 SOURCE I
X
+
+
+
+
+
+
X X X X X + +
+
+
+
+ +
+
+
+
1/95
11
Monitoring the Vadose Zone
-------
NOTES
CROSS SECTION
-Z
Source
ibsdJfL.
Vapors
d
d
k
Vadose ,
t \
r \
r
Leachate
Plume
Saturated ¦¦¦¦ Regional Row
PLAN VIEW
mm
* •
#
*-
m
*3/
m
m
Plume
kT
i Regional Row
Monitoring the Vadose Zone
12
1/95
-------
WELL CONSTRUCTION
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• List six types of drilling methods
• Identify conditions under which the following types of
drilling methods would be used:
1. Air rotary
2. Mud rotary
3. Cable tool
4. Hollow-stem auger
• Describe three methods of well development
• Define the major components of a monitoring well from a
diagram
• List three uses for wells.
NOTE: Unless otherwise stated, the conditions for
performance are using all references and materials
provided in the course, and the standards of
performance are without error.
-------
NOTES
WELL CONSTRUCTION
USES FOR WELLS
• Monitoring
• Remediation
• Lithology
• "Ground truthing"
TYPES OF DRILLING METHODS
• Mud rotary
• Air rotary
• Cable tool
• Rotasonic
• Solid-stem auger
• Hollow-stem auger
1/95
1
Well Construction
-------
NOTES
MUD ROTARY
Advantages
• Availability
• Satisfactory drilling in most formations
• Good depth capability
• Wide variety of formation logging
• Modest cost
• Good gravel pack and casing seal
MUD ROTARY
Disadvantages
• Requires drilling fluid
- Difficult to remove
- May affect sample integrity
• Circulates contaminants
• Mobility may be limited
• Poor rock or soil sample recovery
AIR ROTARY
Advantages
• No drilling fluid required
• Excellent drilling in hard rock
• Good depth capability
• Excellent delineation of water-bearing
zones
• Potential to evaluate hydraulic properties of
water-bearing zones
Well Construction
2
1/95
-------
NOTES
AIR ROTARY
Disadvantages
• Casing may be required during drilling
• Cross contamination of different formations
possible
• Limited equipment availability/mobility
• Difficult formation sampling
• High cost of drilling
CABLE TOOL
Advantages
• Good sample recovery
• Good delineation of water-bearing zones
during drilling
• Highly mobile
• Good drilling in most formations
• Inexpensive
CABLE TOOL
Disadvantages
• Slow
• Requires driving casing in unconsolidated
formations
• May be necessary to double case hole for
good seal or gravel pack installation
1/95 3 WieU Construction
-------
NOTES
ROTASONiC
Advantages
• Fast (20 shallow boreholes/day)
• Versatile (easily penetrates cobbly
materials)
• Clean (cuttings and fluid minimized)
• Excellent sampling (quality cores)
ROTASONIC
Disadvantages
• Cost
• Availability
• Dense or cobbly materials are heated by
vibration (loss of volatiles)
SOLID-STEM AUGER
Advantages
• Fast in shallow, unconsolidated formations
• Inexpensive to operate
• Highly mobile
• Requires no drilling fluid
Well Construction
4
1/95
-------
NOTES
SOLID-STEM AUGER
Disadvantages
• Cannot be used in consolidated formations
• Limited depth capability (175-200 feet)
• Possible borehole collapse after auger is
removed
• Difficult sampling
HOLLOW-STEM AUGER
Advantages
• Highly mobile
• No drilling fluid required
• Problems of hole caving minimized
• Soil sampling relatively easy
HOLLOW-STEM AUGER
Disadvantages
• Cannot be used in consolidated formations
• Limited depth capability (175-200 feet)
• Cross contamination of permeable zones is
possible
• Limited casing diameter
1/95
5
Well Construction
-------
NOTES
MONITORING WELL
CONSTRUCTION
WELL CONSTRUCTION
MATERIALS
• Well screen/riser/well points
- Teflon®
- Stainless steel
- PVC
• Sand/gravel/filter pack
• Bentonite/grout/cement
MONITORING WELL
CONSTRUCTION
• Unconfined aquifer
• Confined aquifer
Well Construction
6
1/95
-------
NOTES
MONITORING WELL ¦ UNC ON FINED AQUIFER
~Steel cap
Wall cap
Grout
Bentonite
Wall screen
Plug
Gravel pack
MONITORING WELL - CONFINED AQUIFER
Potentiometrie _y
suTTace
Bentonite
Well screen
Gravel pack
WELL AND AQUIFER
DEVELOPMENT
• Surge block
• Bailer
• Pulse pumping
• Air surging
1/95 7 Well Construction
-------
NOTES
POOR WELL DEVELOPMENT
Muddy water
"/xxyyx>5
EXXXXXXZXZX
WELL DEVELOPMENT - SURGE BLOCK
1
t
WELL DEVELOPMENT - BAILER
Well Construction
8
1/95
-------
NOTES
WELL DEVELOPMENT ¦ PULSE PUMPING
Pulse pumping
WELL DEVELOPMENT - AIR SURGING
SUMMARY OF DRILLING AND
MONITORING WELL CONSTRUCTION
• Hydrogeologic environment
- Type of formation
- Depth of drilling
• Type of pollutant
• Drilling location
• Monitoring well design
• Drilling equipment availability
• Cost
1/95
9
Well Construction
-------
HYDROGEOCHEMISTRY
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• Evaluate the effect organic and inorganic contaminants have
on groundwater chemistry
• Identify chemical changes in groundwater from petroleum
hydrocarbon contaminants
• Identify chemical changes in groundwater from sewage and
municipal landfill contaminants
• Identify chemical changes in groundwater from acid spills,
coal fly ash, base and ammonia spills
• Define chemical parameters such as hardness, alkalinity, pH,
Eh and how these parameters effect water chemistry
• Evaluate the carbonate buffering system on groundwater
• Define dense nonaqueous-phase liquids (DNAPLs) and light
nonaqueous-phase liquids (LNAPLs)
• Identify gas evolution in uncapped landfills.
NOTE: Unless otherwise stated, the conditions for
performance are using all references and materials
provided in the course, and the standards of
performance are without error.
-------
GROUNDWATER FLOW RATES
AND MODELING
PERFORMANCE OBJECTIVES
At the end of this lesson, participants will be able to:
• Describe the physical, chemical and biological processes that
affect groundwater flow and contaminant transport
• List three factors that groundwater models can predict
• List three problems associated with groundwater models used
in groundwater assessment
• Identify misuses of groundwater models.
NOTE: Unless otherwise stated, the conditions for
performance are using all references and materials
provided in the course, and the standards of
performance are without error.
-------
NOTES
GROUNDWATER FLOW
RATES AND MODELING
PHYSICAL PROCESSES
• Advection
• Hydrodynamic dispersion
• Molecular diffusion
• Density stratification
• Immiscible phase flow
• Fractured media flow
CHEMICAL PROCESSES
• Oxidation-reduction reactions
• Radionuclide decay
• Ion exchange
• Complexation
• Cosolvation
• Immiscible phase partitioning
• Sorption
1/95 1 Groundwater Flow Rates and Modeling \
-------
NOTES
BIOLOGICAL PROCESSES
• Microbial population dynamics
• Substrate utilization
• Biotransformation
• Adaptation
• Cometabolism
Advection
Distance from source
DARCY'S LAW
Q = KIA
• Q
= discharge
• K
= hydraulic conductivity
• 1
= hydraulic gradient
• A
= area
Groundwater Flow Rates and Modeling
2
1/95
-------
NOTES
~ long path
!""~ short path
Path
length
Friction
in pore
I Advection
K Plus
I \dispersion
Distance from source
2
K,
-~ :
K,
-~ •
Co •"
K,
*<
° ^ ¦
K,
i -
cf
tJ
A
-------
NOTES
CONCENTRATION
AT DISTANCE "L"
c =
=&>
,,ic ("biSi+"" ($),rfc
DL = longitudinal dispersion coefficient
C = solute concentration at source
o
v = average linear velocity
L = distance
t = time
erfc = complementary error function
t
c
o
o
c
o
o
Advection
plus
retardation
I Distance from source I
RETARDATION
R = 1 X Kd
n
R = retardation factor
A = bulk density
= distribution coefficient = (K*. )(foc)
n = porosity
Contaminant Velocity:
v = contaminant velocity
v = ground water flow velocity
R, = retardation factor for contaminant x
Groundwater Flow Rates and Modeling
4
1/95
-------
NOTES
Hypothetical contaminant plume
with a small transverse dispersivity
Waste
> j _^
Hypothetical contaminant plume
with a large transverse dispersivity
Waste
Continuous source
Groundwater flow
One-time source
1/95
5
Groundwater Flow Rates and Modeling
-------
NOTES
ACTIVE DNAPt SOURCE
Ff»« pUSM pluiT'lg
flow
/V// / / / ////
//// F'»eh*«d bedrock
LNAPL source
Top ol
capltay
fringe
Groundwater flow
Dissolved LNAPL
plume
LNAPL source
(inactive)
LNAPL
residual
saturation
Top Of
capillary
fringe
LNAPL Product
Dissolved LNAPL
plume
LNAPL
residual
saturation
Groundwater flow
Groundwater Flow Rates and Modeling
6
1/95
-------
NOTES
4
Diffusion
into rock :::::::::
::::::: matrix
Fracture flow
~ ~ ": ~ ~ ::: ~ !:! ~::
Fractured porous rock
PRIMARY MODEL TYPES
Defined by Objective
• Screening models
• In-depth environmental fate models
MODELS CAN PREDICT
• Spatial variation
• Temporal variation
• Parameter variation
1/95
7
Groundwater Flow Rates and Modeling
-------
NOTES
MODEL DIMENSIONS
ONE-DIMENSIONAL //'
TWO-DIMENSIONAL
THREE-DIMENSIONAL
Prediction Reality
MODELING PROBLEMS
• Lack of appropriate modeling
protocols and standards
• Insufficient technical support
• Inadequate education and training
• Widely used, but selection and use
inconsistent
Groundwater Flow Rates and Modeling 8
V
-------
NOTES
MOST COMMON EPA MODELS
Name
Relative Use
MODFLOW
29
HELP
24
RANDOM WALK
21
USGS-2D
20
USGS-MOC
19
KEYS TO SUCCESSFUL
USE OF MODELS
• Proper input data and parameter
estimates
• Effective communication
• Understanding the limitations of the
model
G.I.G.O.
Garbage in = Garbage out
The first axiom of computer usage
1/95
9
Groundwater Flow Rates and Modeling
-------
NOTES
Selection Criteria for Mathematical
Models Used in Exposure
Assessments:
Ground-Water Models
U.S. EPA. 1988. EPA/600/8-88/075.
MODELING PROCESS
• Problem characterization
• Site characterization
• Model selection criteria
• Code installation
• Model application
I Ground-Water Flow |
| Water Jbbte or Confined Aquifer? \
I Porous Media or Fracture Flow? 1
I 1, a, or 3 Dimensionat? \
I Single Phase or Mutti-Phass? ~~]
Homogeneous or Heterogeneous?
Hydraulic Conductivity, Recharge.
Porosity. Specifics Storage
I Single Layer or Multi-Layer? |
Constant or Variable
Thiokness Layers?
r Steady-State or Transient? \
Select the Appropriate Analytical or
Numerical Ground-Water Flow Code
or
Continue with the Decision Tree
and Select a Combined
Ground-Water Flow and
Contaminant Transport Model
Groundwater Flow Rates and Modeling
10
1/95
-------
NOTES
WATER TABLE OR
CONFINED AQUIFER
• Water table
• Confined (majority)
• Combination of both
POROUS MEDIA/
FRACTURE FLOW
• Porous media (majority)
• Fractured media
• Combination of both
1,2, OR 3 DIMENSIONAL
• 3 dimensional (preferred)
• Availability of data
1/95
11
Groundwater Flow Rates and Modeling
-------
NOTES
SINGLE PHASE OR
MULTI-PHASE
• Few models available for multi-phase
flow
HOMOGENEOUS OR
HETEROGENEOUS
• Homogeneous if:
- Conductivity values are within
an order of magnitude
- Recharge, porosity, and storage
values vary less than 25%
SINGLE LAYER OR
MULTI-LAYER
• Single layer aquifer if:
- Hydraulic conductivities are
within an order of magnitude
- Hydraulic gradients and porosity
are within 25%
- Flow direction is same
Groundwater Flow Rates and Modeling 12 1/95
V-
-------
NOTES
CONSTANT OR VARIABLE
THICKNESS LAYERS
• Constant or uniform if thickness
changes less than 10%
STEADY-STATE OR TRANSIENT
• Steady-state if water table fluctuations
are less than 10%
• Transient is difficult to implement
• Select the appropriate analytical or
numerical groundwater-flow code
or
• Continue with the decision tree and
select a combined groundwater-flow
and contaminant transport model
- Compatible but separate models
- Combined flow and transport
model
1/95
13
Groundwater Flow Rates and Modeling
-------
NOTES
I Contaminant Transport I
I Point, Una, or Areal Source? 1
I Initial Value or Conatant Sourcm? |
¦
n. 3. or 3 Dimensional? I
rrossSssiri
Adsorption?
" Temporal Variability
* Spatial Variability
Degradation?
* >*» Order/2nd Order
~ Radioactive Oaoay
Density Effects?
* Thermal and/gr Concentration
Select the Appropriate Analytical or
Numerical Contaminant Transport Coda
POINT, LINE, OR
AREAL SOURCE
• Point source: pipe outflow or well
• Line source: trench
• Areal source: waste lagoon or
agricultural field
• Volume source: volume in
groundwater
INITIAL VALUE OR
CONSTANT SOURCE
• Instantaneous pulse
• Continuous release
- Constant
- Variable
Groundwater Flow Rases and Modeling
14
1/95
-------
NOTES
1,2, OR 3 DIMENSIONAL
• 3 dimensional unless lower dimension
is justified
• 1 dimensional generally predicts
higher concentrations
DISPERSION
• Represents spreading of solute
caused by mechanical mixing
• Difficult to measure in the field
• Requires field calibration
ADSORPTION
Temporal/Spatial Variability
• Process whereby dissolved chemicals
become attached to solids
• Current practice: lump chemical and
biological processes into retardation
1/95
15
Groundwater Flow Rates and Modeling
-------
NOTES
DEGRADATION
1st/2nd Order - Radioactive Decay
• Degradation results from:
- Biological transformations
- Hydrolysis
- Other chemical reactions
DENSITY EFFECTS
Thermal and/or Concentration
• Naturally occurring situations normally
not affected by density
• Landfill leachates often affected by
density
• Select the appropriate analytical or
numerical contaminant transport code
- Transport model compatible with
groundwater-flow model
- Combined groundwater-flow/
contaminant transport model
Groundwater Flow Rates and Modeling
16
1/95
-------
NOTES
SOURCES OF MODELS
AND MODEL INFORMATION
Superfund Exposure Assessment Manual
Chapter 3 - Contaminant Fate Analysis
(35 Models)
U.S. EPA. 1988. 540/1-88/001.
SOURCES OF MODELS
AND MODEL INFORMATION
National Ground Water Association
6375 Riverside Drive
Dublin, Ohio 43017
614 761-1711
1-800-551-7379
SOURCES OF MODELS
AND MODEL INFORMATION
International Groundwater Modeling Center (IGWMC)
Institute for Ground-Water Research and Education
Colorado School of Mines
Golden, Colorado 80401-1887
(303) 273-3103
1/95
17
Groundwater Flow Rates and Modeling
-------
PROBLEM 1
Flow Net Construction
-------
PROBLEM 1: FLOW NET CONSTRUCTION
GENERAL DISCUSSION
Groundwater-level data can be used to determine direction of groundwater flow by constructing
groundwater contour maps and flow nets. A minimum of three observation points are needed to
calculate a flow direction. The procedure is first to relate the groundwater field levels to a
common datum - map datum is usually best - and then accurately plot their position on a scale
plan, as in Figure 1. Next draw a pencil line between each of the observation points, and divide
each line into a number of short, equal lengths in proportion to the difference in elevation at each
end of the line.
The next step is to join points of equal height on each of the lines to form contour lines (lines of
equal head). Select a contour interval which is appropriate to the overall variation in water levels
in the study area. The direction of groundwater flow is at right angles to the contour lines from
points of higher head to points of lower head.
This simple procedure can be applied to a much larger number of water-level values to construct
a groundwater-level contour map such as the one in the example. First, locate the position of
each observation point on a base map of suitable scale, and write the water level against each
well's position. Study these water-level values to decide which contour lines would cross the
center of the map. Select one or two key contours to draw in first.
Once the contour map is complete, flow lines can be drawn by first dividing a selected contour
line into equal lengths. Flow lines are drawn at right angles from this contour, at each point
marked on it. The flow line are extended until the next contour line is intercepted, and are then
continued at right angles to this new contour line. Always select a contour which will enable you
to draw the flow lines in a downgradient direction.
PROBLEM 1: THE THREE-POINT PROBLEM
Groundwater-flow direction will be determined from water-level measurements made on three
wells at a site as depicted in Figure 1:
A. Given:
Well Number
Head (meters)
1
2
3
26.26
26.20
26.08
B. Procedure
1. Select water-level elevations (head) for three wells as depicted in
Figure 1.
1/95
1
Flow Net Construction
-------
N
WELL 2
( head, 26.20 m )
0 25 50 100
METERS
WELL 1
( head, 26.28 m )
WELL 3
( head, 26.08 m
1
-------
2. Select the well with water-level elevation between the other wells (Well 2)
3. Draw a line between Wells 1 and 3. Note that somewhere between these
wells is a point, labeled A in Figure 2, where the water-level elevation at
this point is equal to Well 2 (26.20 m).
4. To determine the distance x from Well 1 to point A the following
equation must be solved (see Figures 3, 4, and 5):
gi - *3 = ~ #2
Y X
5. Distance Y is measured directly from the map (200 m) on Figure 3.
H,, H2, and H3 represent head or water-level elevations from their
respectively numbered wells.
6. After the x distance is calculated, groundwater-flow direction based on the
water-level elevations can be constructed 90° to the line representing
equipotential elevation of 26.20 m as depicted on Figure 6.
Problem:
Based on the previous instructions for the three point solution use the three head
or water-level elevations depicted on Figure 7 and determine the groundwater-
flow direction for this site.
3
Flow Net Construction
-------
N
WELL 2
( head, 26.20 m )
0 25 50 100
METERS
M
WELL 1
m* ( head, 26.28 m )
26 2°
Point A
i
i
i
® WELL 3
( head, 26.08 m )
Fiaure 2
w
-------
N
WELL 2
( head, 26.20 m ) e>
° 25 50 100
meters
WELL 1
( head, 26.28 m )
26-20 ^
Point A
WELL 3
( head, 26.08 m )
-------
8>
£
9
o
a
(26.28 - 26.20) (26.28 - 26.08)
X 200
OS
X = 80
Figure 4
e°
. ? -
t
-------
N
WELL 2
( head, 26.20 m )
©
0 25 50 100
meters
WELL 1
( head, 26.28 m )
80 m
26.20 m
A
©
WELL 3
( head, 26.08 m )
Figure 5
-------
N
WELL 2
( head. 26.20 m
oo
0 25 50
K. — .
meters
v/
WELL 1
( head, 26.28 m )
26.2° ^
Groundwater-Flow
Direction
Figure 6
WELL 3
( head, 26.08 m )
-------
•
•
. •
•
• •
•
•
•
•
•
•
•
500
•
•
o
CM
CO
•
•
•
•
•
•
•
•
•
•
•
• •
«
•
•
•
•
1 MILE
•
#
#420
•
Figure 7
1/95
9
_ \.
Flow Net Construction -
-------
Cut away
cross-
sect i on
FIGURE 8
DEVELOPMENT OF CONTOUR LINES
Consider an island in a lake and the patterns made on it when the water level recedes. The
shoreline represents the same elevation all around the island and is thus a contour line (Figure
8A). Suppose that the water level of the lake drops 10 ft and that the position of the former
shoreline is marked by a gravel beach (Figure 8B). Now there are two contour lines, the new
lake level and the old stranded beach, each depicting accurately the shape of the island at these
two elevations. If the water level should continue to drop in increments of 10 ft, with each
shoreline being marked by a beach, additional contour lines would be formed (Figures 8C and
8D). A map of the raised beaches is in essence a contour map (Figure 8E), which represents
graphically the configuration of the island.
Flow Net Construction
10
1/95
-------
PROBLEM 2: EXAMPLE OF FLOW NETS AND HYDRAULIC GRADIENTS
Purpose
The exercise will employ basic principles defined in the determination of groundwater-flow
directions. Groundwater gradients (slope of the top of the groundwater table) will be calculated
as shown in the three-point problem (problem 1) in this problem.
Key Terms
head—The energy contained in a water mass produced by elevation, pressure and/or
velocity. It is a measure of the hydraulic potential due to pressure of the water column
above the point of measurement and height of the measurement point above datum which
is generally mean sea level. Head is usually expressed in feet or meters.
contour line—A line which represents the points of equal values, i.e. elevation,
concentration, etc.
equipotential line—A line which represents the points of equal head of groundwater in an
aquifer.
flow lines—Lines indicating the flow direction followed by groundwater toward points of
discharge. Flow lines are always perpendicular to equipotential lines. They also indicate
direction of maximum potential gradient.
Procedure
1. Review Figures 8-11.
2. Select an appropriate contour interval that fits the water-levels available and the size of
the map on Figure 9. (Twenty-foot contour intervals should be appropriate for this
problem.)
3. Draw the equipotential lines on the map (Figure 10) interpolating between water-level
measurements in a similar manner as in problem 1.
4. Construct flow lines perpendicular to the equipotential lines drawn in step 3 (see
Figure 11.)
1/95
11
Flow Net Construction
-------
101.9
96.2
94.8
89.4 88.9
0
99.6
94.8
.91.0
99.1
e
102.0
100.8
102.4
Scale: 1M = 425'
101.9
101.8
FIGURE 9
WELL LOCATIONS AND HEAD MEASUREMENTS
101.9
102.0
100.8
102.4
101.8
Scale: 1
101.9
FIGURE 10
EQUIPOTENTIAL LINES WITH WELL HEAD MEASUREMENTS
Flow Net Construction
12
1/95
-------
100.8
Scale: 1" = 425'
102.4
0
101.9
0
101.8
FIGURE 11
FLOW LINES ADDED TO EQUIPOTENTIAL LINES AND
CALCULATION OF HYDRAULIC GRADIENT
5. The hydraulic gradient is calculated by measuring the scale distance between equipotential
lines along a flow line that crosses the site, and dividing that value into the calculated
change in head across the same distance (H2 - Ht)
- H2 = A H
L L
For example (see Figure 11):
Head at A = 100' (H,)
Head at B = 90' (Hj)
Measured distance between the points is 850' (L)
Head at point A minus head at point B divided by the distance between the points equals
hydraulic gradient (slope from point A to point B).
100 feet - 90 feet . 10 m.012 feet/foot
850 feet 850
Select a distance on your contour map between two contour lines and compute the
gradient. ,
/¦y
A V
1/95 13 Flow Net Construction^
-------
PROBLEM 3: FLOW NET CONSTRUCTION
After completing the contour map in Problem 2, plot a profile of the site's groundwater surface
at Y-Y' on Figure 12.
Procedure
• Vertically project the contour lines that intersect line Y - Y' on map in Figure 12,
to the dashed line labeled Y - Y' below this map and above the graph for the
site's profile.
• Be sure to label each mark on this line with it's respective elevation.
• Plot each elevation point on the graph using the vertical scale given.
• Connect the points on the graph. You have now constructed the site's
groundwater-surface profile. This profile also represents a cross section.
Flow Net Construction
14
1/95
-------
•420
380
•400
/
1 320
4801
380
380
520
340
1*280
400 • 360 n g,1 360
\ J «
360 • \
... Otf>_ - - 300 I
320 x
Y'
500
460
320
*
340
1340 380
• 420
\
\
360
• 400
• 420
1 MILE • 480
400'
1440
N 340
*
\
360
'420
• 380 • 420
0
•400
420
*460
Y'
500
400
I—
LU
LU
300
Figure 12
15
Flow Net Construction
-------
PROBLEM 4: FLOW NET CONSTRUCTION
Site Name: Bakers Quarry
Location: Tippersville, Maine
SITE HISTORY/OPERATION
The quarry operation began in 1905 providing construction grade granite locally and was closed
in 1928 when the volumes of groundwater seeping into the pit made it economically unfeasible to
continue mining (Figure 13). The site was abandoned and the pit filled with water. The owners
of the quarry declared bankruptcy and ownership fell to the city of Tippersville in lieu of
delinquent tax payments.
The quarry was used as a swimming hole and occasional dump site for locals until 1958, when
several children drowned. The site was fenced and patrolled to prevent swimming. Uncontrolled
dumping by individuals and local industry increased dramatically with the swimming ban.
Dumping took place around the rim of the quarry and periodically the bulldozer from the town
landfill was used to push material into the pit. Gradually the pit was filled and several fires
forced the town to terminate dumping in 1971. The surface of the site was covered with local
material, primarily sand and gravel.
The site gained notoriety when an area-wide survey identified it as a potential industrial dump
site. A preliminary site investigation, started on 4/14/82, including sampling a spring located
approximately 25 feet from the limits of quarrying. Priority pollutant analysis of this sample
identified ppm levels of polychlorinated biphenyls and trichloroethylene. Results from this
preliminary investigation were used to justify a more extensive hydrogeologic study of the site.
ELEMENTS OF THE HYDROGEOLOGIC INVESTIGATION
The first step of this investigation was to do a literature review of geologic information. A
discussion with a local amateur geologist revealed a paper from a geologic investigation
performed during active quarrying. Information from this study and observations at an outcrop
on-site provided a geologic background for the investigation. The quarry material is a slightly
gneissoid biotite-muscovite granite. Several dikes were identified in the quarry wall.
The probable high permeability and infiltration rate of the less consolidated waste material
compared to that of the granite, could cause groundwater mounding in the pit area. Potential
mounding, and inadequate information about groundwater flow direction dictated a ringing of the
site with monitoring wells.
Twenty-two monitoring wells were planned and installed at the site from 10/1 to 11/14/82.
Eleven were installed in bedrock, the unconsolidated zone sealed with steel casing and grouted.
Eleven monitoring wells were installed in the unconsolidated heavily weathered bedrock or
unconsolidated zones. For the purpose of this problem set you will only be using data from the
eleven wells listed in Table 1. An explanation of this data is depicted in Figure 14.
1/95
17
Flow Net Construction
\
-------
\ ^ \ \
N . JBt fx "/
Swamp
MW11
MWI ' ®
1200'
I t \ ^ ^ 'Vy s s s A
Site Boundary
FIGURE 13
SITE MAP - BAKERS QUARRY, TIPFERSVILLE, MAINE
Flow Net Construction
18
1/95
-------
TABLE 1
MONITORING WELL DATA
WELL
NUMBER
(a)
TOP OF
CASING
ELEV.
(feet)*
(b)
GROUND
SURFACE
(GS)
ELEV.
(feet)*
(c)
GROUND-
WATER
ELEV.
(feet)*
(d)
WELL
DEPTH
(feet
below GS)
BOTTOM
OF WELL
ELEV.
(feet)*
(e)
BED-
ROCK
DEPTH
(feet
below GS)
MW 1
87.29
84.79
80.49
151.9
-67.11
7.5
MW 2
89.94
87.99
84.69
103.05
-15.06
7.5
MW 3
88.04
85.44
75.29
103.1
-17.66
2.0
MW 4
82.50
79.80
72.40
102.3
-22.50
14.0
MW 5
82.50
80.05
73.40
102.45
-22.40
8.5
MW 6
72.50
69.50
67.50
99.6
-30.10
9.0
MW 7
80.58
78.28
74.78
99.5
-21.22
8.0
MW 8
86.03
83.53
76.93
99.2
-15.67
8.5
MW 9
114.01
111.21
92.36
99.9
11.31
10.5
MW 10
108.67
106.67
93.97
98.7
7.97
10.8
MW 11
105.07
103.37
94.97
102.1
1.27
2.5
* Datum: mean sea level
1195
19
Flow Net Construction
-------
MW 1
Cb3
CbD C<0
—X
ai. 29
84.79
* *
151 9
C«3
CO
7.5
Bedrock:
80.49
Datum Csea I eve I 3
Ca} Top of casing elevation Cfeet}
Cb} Ground surface elevation £feet}
CO Groundwater elevation Cfeet}
Cd} Well depth below ground surface £feet}
Ce} Bedrock depth Cfeet}
FIGURE 14
MONITORING WELL ELEVATIONS
Flow Net Construction
20
-------
DEVELOPMENT OF SITE PROFILES
Purpose
The development and comparison of topographic profiles across the site will help the student to
understand the variability of the surface terrain usually found on most of the larger sites. The
water-table profile will also be constructed. These profiles will be useful during the next
problem, "Flow Nets and Determination of Hydraulic Gradients."
Procedure
1. To construct cross-section lines, lay the edge of a piece of paper along the cross-section
line selected and draw a straight line. Mark the location of the monitoring wells along
the edge of the paper. (The placement of some wells may need to be projected, as not all
of the wells lie along a straight line.)
A - A' MW 9, MW 2, and MW 4 (in that order)
B-B' MW 1, MW 8, and MW 7
C-C' MW 11, MW 3, MW 7, and MW 5
NOTE: One should be aware that projection of wells to a cross-section line could cause
distortions which might affect interpretation of the distribution of subsurface geology or soil.
2. Using the graph paper provided, transfer these well locations to the bottom of the page
along the horizontal axis.
3. The vertical axis will represent elevation in feet. Mark off the elevations in ten foot
increments. Each division of the graph will represent an elevation increase of two feet.
4. Graph the ground surface elevation for each of the chosen monitoring wells. (This
information is found in the monitoring well data, Table 1.)
5. Graph the groundwater elevations for these same locations.
6. Repeat this procedure for the other cross-sections lines.
7. Compare the topographic profile to the water table-profile. Are they identical? After
looking at this data, are there any conclusions that can be drawn?
1/95
21
Flow Net Construction
-------
PROBLEM 2
Geological Cross-Section Construction
-------
PROBLEM 2: GEOLOGIC CROSS-SECTION CONSTRUCTION
Materials necessary to construct cross section:
• Graph paper. Use vertical scale of one graph paper division per 20 feet.
• Colored geologic map from geologic report that covers the area surrounding the
location of the cross section. The cross section is labeled on the map as A - A'.
• Description of major geologic units from a geologic report.
• Six water well logs which include a driller's description of the sediments and rocks
encountered during the drilling of each well. Location of the wells are depicted on
the geologic map and the following topographic quadrangle map. These logs will be
used to construct the geologic cross section.
• Topographic quadrangle map depicting the ground surface elevation along this cross
section. This map will be used to construct the surface profile at the cross section.
• Ruler and colored pencils will be supplied upon request.
Procedure to follow in the construction of this cross section:
• The instructor will divide the students into groups after discussing the materials
included with this exercise.
• Each group will first select an individual to construct a common surface profile that
the other students will use to put their soil boring interpretation for each well on the
cross section. This person will use the same procedure employed earlier to construct
the profile in the flow net exercise.
• Each group will then determine who will evaluate the soil boring information from
each well log and define which major geologic units are present. This interpretation
will be based on the geologic information already provided. Hint: The geologic map
indicates the major unit at the top of each soil boring.
• When the major unit intervals are defined on each boring, this information will be
constructed on the graph paper provided using the vertical scale given above. It is
suggested that one use the same symbols as those used to describe the major geologic
units in the geologic report.
• After the surface profile is completed, the constructed boring log for each well will
be transposed onto this profile. This is done by placing the top of each constructed
well log at its appropriate surface location on the profile. This will eliminate the need
1/95
1
Cross-Section Construction
-------
of calculating the elevation for the top of each major geologic unit found in each
boring.
Once this is accomplished each group will attempt to correlate these major geologic
units between the six soil borings.
Cross-Section Construction
2
1/95
-------
Depth of Soil
Lithologic
Boring Log
Boring Log
Boring
Description
Example
Example
£T
# 1
#2
•S
o.
£
0.0
0 - 5.0 ft
Tan, silty clay
• > >
(SC)
.
5.0
•
SC
5.0 - 10.0 ft
Light brown,
.
sandy silt
..........
(SS)
-
• 9 •
SS
10.0 - 15.0 ft
Brown, fine-grain
10.0
» « O O
a • o •
sand
© o a « • • • o
(FS)
¦ a • o a a « • « •
-
« a
FS
15.0 - 17.5 ft
Dark brown,
!>•••• 0*» • • B » 0
coarse-grain
15.0
sand
Q«Q**oQ«*o
(CS)
o o O • • 0 o • * •
CS
• O O O O O O 0
17.5 - 20.0 ft
Reddish brown
-
OOOOOOOO
gravel
OOOOOOOO
G
(G)
20.0
OOOOOOOO
OOOOOOOO
20.0 - 22.5 ft
Red Clay
C
(C)
1/95
3
Cross-Section Construction
-------
CLAY PLUG
HORIZONTAL
BEDDING
SCOUR AND FILL
PREVIOUS
FLOOD PLANE
h ) ')
ZZZJ
{o
VARIOUS
X-BEDDING
STYLES
PLANAR
X-BEDDING
TROUGH X-BEDDING
MASSIVE
GRAVEL BED
CHANNEL LAG
-------
GRAIN SIZE DECREASES
FINING UPWARDS SEQUENCE
SORTING
POOR GOOD
~
STREAM VELOCITY DECREASES
1/95
5
Cross-Section Construction
-------
;
DESCRIPTION OF GEOLOGICAL UNITS FOR
CROSS-SECTION OF COLBERT LANDFILL-SPOKANE, WASHINGTON
Map Symbol Description
Quaternary Sediments
Qa Alluvium or stream deposits (Holocene)—Composed of silt, grayish-orange
sand, and gravel sediment that is well sorted and stratified. These deposits are
found in floodplains, river terraces, and valley bottoms.
Qfg Flood deposits (Pleistocene)—Poorly sorted, stratified mixture of boulders,
gray cobbles, dark gray well rounded gravel, and coarse sand resulting from
multiple episodes of catastrophic outbursts from glacial-dammed lakes, such
as glacial Lake Missoula. The Little Spokane River valley was one of the
main channelways for outburst flood waters from this ancient lake.
Qls Alluvial fan deposits (Pleistocene)—Composed of unstratified and poorly
sorted (heterogeneous and anisotropic) clay-, silt-, pink sand-, and gravel-size
sediment. Some fan deposits contain large blocks of gray basaltic rock as
much as 8 meters (26 feet) in diameter.
Qglf Lacustrine deposits (Pleistocene)—Composed of crumbly sediment of white
clay, gray silt, and fine green sand, inter-bedded (mixed) with flood deposits
(Pleistocene), composed of poorly sorted, but stratified mixtures of boulders,
cobbles, gravel, and green sand.
Columbia River Basalt Group—Tertiary (Miocene)
Mvwp Wanapum extrusive basalt flows. These flows consist of dense, greenish-
black, and weathered basalt; some have a vesicular (mineral filled gas bubble)
texture.
Mcl Latah Formation—White to yellowish gray-siltstone and claystone, grayish-
green sandstone of lacustrine (lake) origin and grayish-orange sandstone from
fluvial (river/stream) depositional environments.
Intrusive Igneous Rock—Cretaceous Period, Mesozoic Era
Kiat Mount Spokane granite-massive, medium-grained pale, reddish-brown granite
that is present on Mount Spokane.
Cross-Section Construction 6 1/95 '0 ^
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-------
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