-------
Kriged Potentiometric Surface
49
o-
710
'04
::o
730
O"
600
500
575
475
525
EAST COORDINATE, 100 FT
Kriging Outputs
POTENTIAL SURFACE
ERROR
.860
7 0
SITE
[850
SIT E
'800
840
840
060
20
1-10
-------
Hand-Drawn Fotentiometric Surface
133
190T-*
/' /
128
196
194
192.
185
184
300
900
Kriged Potentiometric Surface
300
METERS 0
9QQ
1-11
-------
FLCW KJDli DEVELOPI-Orr AND CALIBRATION
POTENTIAL
BOUNDARY CONDITIONS
STRUCTURE
STRESS
POROSITY
PERMEABILITY
TRANSPORT MDDEL DEVELOPMEfn1 AND CALIBRATION
DISPOSAL HISTORY AND AMOUNTS
DISPERSION (LONGITUDINAL AND TRANSVERSE)
RETARDATION FACTOR
DEGRADATION
VOLATILIZATION
Finite Element Model Grid
' /-A_-,c/\ a i
. " /\/-V/\>vK' V-v\ /. /-V \ A• V
/u ¦ /X- /\/-Xv>"/.\/N/v:vo/A/.\a \ ¦'
1/Av - / ^ ' ¦ A x- /\ 7 V V'.V-V-V \ / \ A \ /
-N/'A/"/ V ¦ A".' \/ V.V-V\"'V V -
Aj\ \'vX'\ 7- /\ / V-VA -'W«-\ '¦
• • AA'A'v)-..
¦* • -\- • \j\, \
>._xX-yxV.
>^AAv>
t
mens 533
rtrr 9X1
1- 12
-------
Model-Predicted Potentiometric Surface
190
METERS
300
FEET
900
1 - 13
-------
Critical Elements in Site Characterization
Hydrogeologic Settings, Subsurface Hydraulics,
and Ground-V\fater Quality Impacts
Flow and Transport Characteristics
RELEASE
INFILTRATION
TRANSPORT
SOURCE
AQUIFER
UNSATURATED ZONE
MONITORING WELL
y
RECHARGE
\
FLOW
\
/
0,
SCHARGE
Hydrogeologic Settings
• Has Common Hydrogeologic Characteristics
• Useful in Developing initial Conceptual Model
• Factors
o Geologic Fabric
o Recharge
o Discharge
o Topography
o Depth to Ground Water
• Nalural Ground-Water Constituents
o Inorganics
o Organics
o Gases
l- 14
-------
HYDROGEOLOGIC SETTINGS
Considerations
• Depositional Enviroments: Permeabiliiy
• Aquifer Interconnection: Recharge/Discharge
• Depth to Ground Water: Time of Travel
• Unsaturated media: Sorption
Principal Groundwater Regions in the U.S.
Kv.-/«v,k»y.v
0 100 200 300 400 600
MILES
Ranges of DRASTIC Parameters for
Piedmont and Blue Ridge Region
Min
Max
Depth to Water Table, ft
5
100+
Net Recharge, in/yr
0
10
Topography, %
2
18+
Hydraulic Conductivity, GPD/ft2
1
2,000
Soil Media
Aquifer Media
i-
Absent, Loam, Clay Loam,
Sandy Loam
Metamorphic/Igneous; Sand
and Gravel; Thin Bedded SS,
LS, SH; Weathered
Metamorphic/Igneous
-------
Typical Piedmont Flow System
FLOW MODEL
LAYER
GROUND SURFACE
LAYER
LAYER
B
CONCEPTUAL
MODEL
LAYER
ALLUVIAL AND RESIDUAL ££&
SILT WITH CLAY|^;p
LAYER 1
.0 ®
v a
:o*>
: o
0
O• 0 • 0 o-
0 o 0 '-3. a
o«
n " 0 .
U0-» * <•',
0 o ¦ Q O
'• 0 V*7
r\ ¦ ¦? r>
o ^ SAND AND GRAVEL ¦ % o
- » ~o fc' O " ' 1} Q »0
0 tf O Q°. Oo's^oaoo
O o o a , ° t -
U o o °-o D 0 . o ¦ o °» ° r>
/'.„ O-.-Q a.' o « * o °
•v 11 ''^s-T:
LAYER 2
¦ c
n v-
o
WEATHERED BEDROCK:-':
T;'.'.'.;-. " (DOLOMITE) -
— IMPERMEABLE
UNWEATHERED
BEDROCK
/ T
, >¦ LAYER 3
LAYER 4
NOT TO SCALE
Basic Flow Equations
V = KAh/Ax
v — K Ah
ne Ax
v = kdg Ah
une Ax
K = f(water, formation)
k = f(formation)
1" 16
-------
FLOW DIRECTION
LOCAL FLOW DIRECTION = f (local gradient)
GROSS FLOW DIRECTION = K I (local gradient)
= K J (local flow gradients)
UNCERTAINTIES DUE TO:
• TIME INEQUIVALENCE
• MEASUREMENT ERROR
• SPATIAL INEQUIVALENCE
SPATIAL CONSIDERATIONS
HYDROSTRATIGRAPHIC EQUIVALENCE BASED ON:
GEOLOGIC FABRIC (STRUCTURES, STRATIGRAPHY)
IIYDROLOGIC CHARACTERISTICS (MEAN VALUES, HETEROGENEITY AND
ANISOTFOPY OF HYDROLOGIC PARAMETERS)
HYDROatEXICAL EQUIVALENCE BASED ON:
PROPERTIES OF TOE FLOW SYSTE-l (HYDROSTEATIGRAPHY, REQIARGE,
VELOCITY, DIFFUSION, AND DISPERSION)
CONTAMINANT CHARACTERISTICS (DENSITY, SOLUBILITY, VISCOSITY,
CONCENTRATION, CHEMICAL PROPERTIES]
TEMPORAL CONSIDERATIONS
GROUND-WATER REQIARGE
GROUND-WATER '..TIHDRAWf\L (DISCHARGE)
PERCHING
FLOW RATE
FLOW RATE = f (permeability, porosity, gradient)
UNCERTAINTY IN GRADIENT AS BEFORE
UNCERTAINTY IN POROSITY IS SMALL
UNCERTAINTY IN FLOW RATE - f (uncertainty in permeability)
FIELD PERMEABILITY * LAB PERMEABILITY
(Samples and Procedures not representative)
1-17
-------
Factors Affecting Conductivity Measurements
Medium Factor Measured in Lab?
Soil Fractures, Desiccation No
Sand Stringers No
Sample Integrity No
Aquifer Fractures, Solution Cavities ?
Vertical Component Yes
Horizontal Component No
Sample Integrity ?
Aquifer Hydraulic Conductivity Variations
Data Range
Generic in Orders Mean
Classification of Magnitude Value, cm/s
Fractured crystalline 3.0 1.53 x 10 "3
silicates
Fractured-solutioned 4.0 6.42 x 10 ~2
carbonates
Porous consolidated 4.6 1.16 x 10 ~2
carbonates
Porous consolidated 3.0 1.79 x 10 ~3
silicates
Porous unconsolidated 5.9 5.55 x 10 ~2
silicates
Fractured consolidated 4.0 2.4x10~3
silicates-shale
1-18
-------
Transmissivity Distribution for Rotary Wash and
Air Drilled Wells
10
15 8
8. 6
Mode (Wash)
\
Mean (Washl
\
Mode (Air)
/Mean (Air)
ri
r -1 flotary Wash
~ Air Rotary
n
£1
10 10 10° 10 10
Transmissivity (m'/day)
10'
FOUR IRENES PEDALED BY PUMPING TEST DATA:
SANDS AND GRAVELS HAVE HIGIER TRANSMISSIVITIES THAN
FRACTURED BEDROCK, REGARDLESS OF HE DRILLING METHOD
BEDROCK WELLS DRILLED BY ROTARY WASH HAVE LCMER TRANSMISSIVITIES
THAN BEDROCK WELLS DRILLED BY AIR ROTARY, REGARDLESS OF THE
TYPE OF SCREEN OR SAt© PACK
FOUR-INCH DIAMETER MONITOR WELLS HAVE HIGHER TRANSMISSIVITIES
THAN 1W>INCH DIAMETER WELLS (ALL DRILLED BY AIR RCTAKY)
TRWEMISSIVITICS OF SIX-INCH DIAMETER WELLS WERE LESS THAN
rOUR=INdl DIAMETER WELLS
1- 19
-------
HYDROLOGIC ERROR ROOTS
1. 3-D Well Location
2. Improper Well Construction
o Diameter
o Installation Techniques
3. Improper Measurements
• Length of Well Tests
o Type of Wei! Test
4. Improper Interpretation
SAMPLING UNCERTAINTIES
GROUNDWATER
• Inadequate development and purging
• Improper construction
® Fracture flow - chemostratigraphic equivalence
0 Domestic and Production Wells
• Improper Sampling Methods
• Preservation and Shipping
(anaerobic, static) -*¦ (aerobic, agitated)
SOILS & SEDIMENTS
0 Cross Contamination
® Spikes
® Representativeness
DATA SUSPECTS
CONTAMINANT LEVEL
SUSPECT
HIGH
• IMPROPER SAMPLING
• MISSING ANALYTES
• CONTAMINATION OF OTHER SAMPLES
LOW
• SAMPLE CONTAMINATION
• DEGRADATION
• IMPROPER SAMPLING
PERMEABILITY VALUES
SUSPECT
HIGH
• IMPROPER TESTING OR ANALYSIS
• MISCONCEPTUALIZATION
LOW
• IMPROPER WELL CONSTRUCTION
• LABORATORY MEASUREMENTS
1-20
-------
Critical Elements in Site Characterization
Contaminant Properties Affecting Transport
PROPERTIES AFFECTING FLOW AND TRANSPORT
Physical Properties
• Density
• Solubility
o Viscosity
• Surface Tension
Chemical Properties
• Oxidation-Reduction Behavior
• Sorption/Retardation
• Degradation
Depth to Water in a Confined and
Unconfined Aquifer
DEPTH
TO WATER
(UNCONFINED)..:- 7
WATEpi TABLE '..7>
jiT * * ^' 1 ,
STREAM
¦ DEPTH TO WATER
:• _ (confined) -fVv^ J
' UN CON FINED AQUIFER
1- 21
-------
Infiltration Through Clay Liner and Soil Column
PONDED
LEACHATE
CLAY
LINER
SOIL
COLUMN
MOISTURE
CONTENT
0 0
FLUX
CONTROLLED
BY CLAY
LINER
PARTIALLY
SATURATED
ZONE
Time of Travel Formulas
T = L (~K~r)
8_
l^sat ®sat
Unsaturated Steady State
T =
L2 nf
AH Ksat
Saturated Steady State
1-22
-------
Contaminant Movement in Discharge Area
A. CONTAMINANTS MOVE
-—WITH WATER
B. WITH DENSE
CONTAMINANT
Movement of Dense Soluble Contaminant Plume
in Discharge Area
1-23
-------
Mixing of Release and Flux to Produce
Downgradient Concentration
1 kg/day
—
1000 f/day
„ 1 kg/day
C = 2 — =1000 mg/l
1000 i'/ day
Solubility of Various Chromium Species Under
Reducing Conditions
Cr(OH)
O "10
1-24
-------
Solubility of Various Chromium Species Under
Oxidizing Conditions
-2
;0 *
-4
-6
-8
0\
Cf(OH)
O -10
-12
-14
-16
2
4
6
7
5
3
8
9
10
1 1
12
pH
Reduction of Copper Concentrations from
Unsaturated Zone to Saturated Zone
20.33
17.16
7.63
0.0E 00 25.4 50.8 76.2 101.6 127
UNSATURATED ZONE COPPER INPUT CONCENTRATION (mg/L)
1-25
-------
"Oxidation States" of Functional Groups
Increasing Oxidation State
>
R-H
i t
-c=c-
-C=C- RCOH
o
o
M
R-OH
-c-c-
OH OH
i
o=o
1
R-CI
r2cci2
-cci3
o
o
-H
r-nh2 r-n-r r-n = n+ r - no2
' H
SORPTION/ATTENUATION
Freundlich Sorption
= ^ D ^ W "
Soil Sorption
^OC= ^D^OC
= ^ ocfoc C wn
Retardation Factor
R = V(Water)
V(contaminant)
R = 1 + BKD /ne
1-26
-------
Delineation of Contaminant Plume to Calculate
Contaminant Mass
PLAN VIEW
FLOW DIRECTION
CONTAMINANT
CONTOURS
FACILITY
BOUNDARY
1 ug/f
10 ug/f
DISSOLVED MASS
1,000 kg
SOR8ED MASS
9.000 kg
MONITORING
WELL
ELEVATION VIEW
100 ug/f )10
1 ug/f
Estimating Sorption (Organics)
For Water:
log Koc = -0.55 logS + 3.64
log K qq = 0.937 log Kow — 0.006
For Oily Wastes:
C(Sample) = S(Water) ( 1 + fow Kow)
1-27
-------
Relative Migration of Plumes of Mobile and
Attenuated Contaminants
n
PLUME OF ATTENUATED
CONTAMINANT. KD =5
PLUME OF MOBILE
CONTAMINANT. K0 =0
Multiple Contaminant Plumes
A. ORIGINAL PLUME
FLOW DIRECTION
SfTE
CONTAMINANTS A. B, C
B. DEVELOPED PLUMES FOR CONTAMINANTS
WITH DIFFERING SORPTION COEFFICIENTS
FLOW DIRECTION
CONTAMINANT C CONTAMINANT B
Kd =30 KD =10
CONTAMINANT A
Kd = 3
1-28
-------
Degradation Reaction of Trichloroethyiene
TCE
DAYS
34
TRANS 1, 2 DCE
1, 1 DCE
Cis 1. 2 DCE
DAYS
25,600
VINYL CHLORIDE
Contaminant Plumes Showing Movement of
Degradation Products
TCE PLUME
FACILITY
DCE PLUME
]- 29
-------
TCE Decay Profiles
VINYL CHLORIDE
TRANS-1, 2-DCE
2.0 3.0
TIME (YEARS)
Multiple Contaminants Plumes Showing
Degradation Products
LOW PERMEABILITY
DEPOSITS
SITE
CREEK
OBSERVED
TCE
CONTAMINATION
OBSERVED VC
CONTAMINATION
1-30
-------
TRENCH AREA
LASER RANGE / WATER TANK
SEWAGE TESTTRACK
POWER TREATMENT
SUBSTATION PLANT
METAL PLATING
FACILITY
IVYTP
MAIN DIVERSION
CHANNEL
;-T;Trr*t»
CATFISH
POND
LAYER 1
SATURATED
RESIOUUM
WILCOX AGE
ALLUVIUM
MAIN DIVERSION
CHANNEL
LAYER 2
GRANULAR
POROUS MEDIA
LAYER 4
IMPERMEABLE
UNWEATHERED
BEDROCK
LAYER 3
WEATHERED
OOLOMITE
BEDROCK
VR7ER LEVEL MEASUREMENTS
19800
19780
19760
2:
o
w 19743
z
o
£ 19720
LJ
£ 19703
> 19680
UJ
c 19669
UJ
c
> 19640
19620
19600
1 1 1 I
* « WELL 61504
* < VELL 81B05
* » VELL 81
_i 1 i_
RAINFALL HISTORY
£ 100
§ sz
c
£ 30
G_
£ 20
c
Q_
Q 10
L
-A. A
23 25 30 35 10
ELAPSED TIME CDAYS3
t
55
1-31
-------
20160
WELL 81302
VELL 81 BO 1
19570
19530
19(190
r
60
55
15
35
53
0
5
25
ELAPSED TIME CDflYS)
1-32
-------
MONITORING SYSTEM DESIGN
Presented By:
Charles Kufs
Raymond Scheinfeld
Roy F. Weston, Inc.
Weston Way
West Chester, Pennsylvania
Overview Of Presentation
Indirect Methods for Characterizing Subsurface Migration
Aerial Photographs
Environmental Surveys
Existing Well Surveys
Surface Water Surveys
Biota Surveys
Geological/Hydrological/Soil Surveys
Geophysical Surveys
Methods
Magnetometry
Metal Detection
Electromagnetic Conductivity (EM)
Resistivity
Seismic
Ground-Penetrating Radar (GPR)
Borehole Geophysical Devices
Cost
Factors in the Selection of Geophysical Techniques
Evaluation of Geophysical Data
Soil Gas Surveys
2-1
-------
Direct Methods For Characterizing Subsurface Migration
Soil and Rock Sampling
Hydrologic Measurement
Aquifer Testing
Monitoring System Design
Overview of Monitoring Program Design
Objectives of Monitoring
Monitoring System Components
Data for System Design
Selecting Well Locations
Selecting Well Depths
Selecting Well Configurations
Hypothetical Example 1—Pattern of Contamination
Hypothetical Example 2—Evolution of a Monitoring
System
Problems in Monitoring System Design
Planning Problems
Implementation Problems
Site Condition Problems
Special Problems
Irregularly Shaped Aquifers
Fracture Flow
Aquifer-Contaminant Interactions
Non-Aqueous Phase Liquids
Case Histories
2-2
-------
to
I
CO
Monitoring
System
Design
-------
Monitoring System Design
• Indirect Methods for Characterizing Subsurface Migration
• Direct Methods for Characterizing Subsurface Migration
• Using Direct and Indirect Data in System Design
• Problems in Monitoring System Design
-------
Indirect Methods For
Characterizing Subsurface migration
• Background Records and Literature
« Aerial Photography
• Environmental Surveys
• Geophysics
• Soil-Gas Analysis
-------
Indirect Methods: Aerial Photography
Types of Information Provided
• Historical Development of Site
• Indications of Waste or Leachate
• Geologic, Topographic, and Hydrologic Features
-------
Indirect Methods: Aerial Photography
Types of Aerial Images
• Oblique Photos
• Perpendicular Photos
• Stereoscopic Photos
« Infrared Images
• Other Types of Images
-------
indirect Methods:
Aerial Photography
Sources of Aerial Images
« Government Sources (EPA, USGS, SCS, Archives)
- Relatively inexpensive (Less Than $50)
- Long Delivery Times (4 to 10 Weeks)
- Availability Limited by Scale
• Private Sources
- Relatively Expensive ($20 to $200)
- Short Delivery Times (2 Days to 2 Weeks)
- Availability Limited by Date
-------
Indirect Methods:
Environmental Surveys
• Existing Wei Surveys
© Surface Wafer Surveys
~
• Biota Surveys
• Geologic/Soil Surveys
-------
Scale in Feet
0
C~$ n\*£ r-i cO
^ '-.'J '.-3 .A:/
Existing Fence
Legend
Wooded Area
qOQ. Drainageway
Rip-Rap
O Well Number
Bare Soil or
* Patchy Vegetation
Dead Vegetation or
Stained Soil
S-1 Soil Sample No. 1
DISTRIBUTION OF SITE VEGETATION
-------
Indirect Methods: Geophysics
® Magnetometry
• Metal Detection
• Electromagnetic Conductivity
• Resistivity
• Seismic Reflection and Refraction
• Ground Penetrating Radar
• Borehole Methods
-------
Indirect Methods: Geophysics
Magnetometry Surveys
• Measure Intensity of Earth's Magnetic Field
• Local Magnetic Anomalies Can be Related to
Buried Ferrous Metal
• Depth of Survey up to 50 Feet
• Intensity of Response Related to Mass of Ferrous Metal
-------
Indirect Methods: Geophysics
Types of Magnetometer
• Fluxgates
• Total Field
• Gradlometer
-------
Indirect Methods:
Geophysics
Metal Detection Surveys
« Indicate Distortion of Electromagnetic
Fields by Metallic Substances
• Detect Ferrous and Non-Ferrous Metals
• Depth of Survey up to 15 Feet
• Intensity of Response Related to Surface Area of Metal
-------
Indirect Methods:
Geophysics
Electromagnetic Conductivity (EM) Surveys
• Measure Conductivity of Groundwater and Rock Materia!
• Anomalies Can be Related to Ionic Concentrations
« Depth of Survey up to 200 Feet
• Survey Depth Related to Electrode
Spacing and Orientation
• Used Primarily for Profiling
-------
Indirect Methods: Geophysics
Resistivity Surveys
• Measure Resistance of Subsurface
Materials to Electrical Current
• Can be Related to Stratigraphy or Groundwater Quality
• Used Primarily for Vertical Sounding
• Survey Depth Related to Electrode Spacing
-------
Indirect Methods: Geophysics
Seismic Surveys
• Measure Changes in Energy Waves Transmitted Through
Soil and Rock
M
i
5 • Used to Delineate Subsurface Stratigraphy
• Seismic Refraction Used for Shallow Studies
• Seismic Reflection Used for Deep Studies
-------
Indirect Methods: Geophysics
Ground Penetrating Radar (GPR) Surveys
• Measures Reflection of Energy Pulses Off "Targets"
» Can Identify Stratigraphic Layers,
Groundwater, Buried Waste
• Depth of Penetration Highly Variable,
Up to 100 Feet
• Signal Attenuated Rapidly by CSays and Water
-------
Indirect Methods: Geophysics
Borehole Logs
• Temperature
• Specific Conductance
• Downhole TV
• CaSiper
• Resistivity
« Gamma
• Neutron
• Others
-------
Indirect Methods: Geophysics
Costs for Geophysical Surveys
Magnetometer
Conductivity
Resistivity
GPR
Cost Ranges/Day1
$1,935-$3,890
$1,970-53,960
$2,090-54,655
$2,585-56,100
Field Capacity/Day
50-150 Stations
50-150 Stations
8-20 Stations
5,000-10,000 Linear Feet
1Travel Costs and Survey Grid Not Included.
-------
Indirect Methods: Geophysics
Factors in Method Selection
Magnetometry - lor High Mass, Iron Deposits
Metal Detection - for Shallow, Metallic Deposits Having a
High Surface Area
Conductivity - for Profiling Electromagnetic Contrasts
Resistivity - for Sounding Electromagnetic Contrasts
Seismic - for Delineating Geologic Layers
Having Different Densities
GPR - for Delineating Low-Clay Deposits and Groundwater
-------
Indirect Methods: Geophysics
Complementary Geophysical Methods
Application
Buried Non-Metallic
Wastes
Buried Metallic Wastes
Subsurface Geology
Depth to Water
Leachate Plumes
Primary Methods
GPR, EM
Magnetometry, Metal
Detection, GPR
GPR, Seismic
GPR
EM, Resistivity
Secondary Methods
Resistivity
EM, Resistivity
EM, Resistivity
EM, Resistivity
GPR
-------
Indirect Methods: Geophysics
Data Evaluation Techniques
• Graphical Interpretation
• Method-Specific Models
• Statistical Models
-------
Indirect Methods; Soil Gas
® Measure Chemical Vapors in Soil Voids
• Can be Related to Buried Wastes or Leachate
» Depth of Survey Variable - Typically Less Than 100 Feet
• Can be Qualitative, Semi-Quantitative or Quantitative
-------
Indirect Methods: Soil Gas
Gas-Collection Approaches
• Surface Readings
• Temporary Probes
• Semi-Permanent Probes
• SorpSive Collectors
• Vapor Wells
-------
Indirect Methods: Soil Gas
Analytical Approaches
• Onslte Instrumentation
M
I
• • Sorptive Collectors for Lab Analysis
• Tedlar Bags for Lab Analysis
-------
Direct Methods for
Characterizing Subsurface Migration
• Soil and Rock Sampling
• HydroSogic Measurements
• Aquifer Testing
• Groundwater Sampling
-------
Direct Methods:
Soil and Rock Sampling
• Grab Samples
« Spiit Spoon Samples
ro
i
« « Shelby Tube Samples
• Soil-Core Samples
• Rock-Core Samples
-------
Direct Methods:
Hydrologic Measurements
• Surface Water Discharge and Elevation
• Spring Discharge and Elevation
• Unsaturated Zone Monitoring '
• Groundwater Elevations
-------
Direct Methods: Hydrologic Measurements
Devices for Measuring Depth to Water
Typical
Ease
Purchase
Recording
Device
Accuracy
of Use
Cost
Capabilities
Tape/Popper
0.1
Easy
$15
No
Tape/Marker
0.05
Easy
$20
No
Electrical
0.05
Easy
$200
No
Mechanical
0.1
Difficult
$1,000
Yes
Sonic
1.0
Moderate
$500
Yes
Pressure
0.03
Moderate
$1,500
Yes
Transducer
-------
Direct Methods: Aquifer Testing
• Laboratory Tests
• Slug Tests
• Packer Tests
• "Mini" Pump Tests
• Step-Drawdown Tests
• Pump Tests
• Tracer Tests
-------
Objectives
Assess Groundwater Quality; Delineate Horizontal
and Vertical Rate And Extent of Contamination;
Evaluate Effectiveness of Corrective Actions;
Monitor Long-Term Groundwater Quality
Well Design
Well Materials
Screen Type and Setting;
Security and Identification Measures
System Design
Numbers, Locations,
Depths, and Configurations
of Wells
BmpBementation Procedures Program Design
Well Installation, Sampling; 4 > Sample Analysis Parameters
Laboratory Analysis, and and Frequency; Field
Data Evaluation Procedures and Laboratory QA/QC
Elements of Groundwater Monitoring
-------
Combining Direct and Indirect Data
Some Objectives for Groundwater Monitoring
• Assess Groundwater Quality
• Delineate Horizontal Extent of Contamination
« Delineate Vertical Extent of Contamination
• Evaluate Effectiveness of Corrective Actions
-------
Combining Direct and indirect Data
Monitoring System Components
Well Design - Wei! Materials, Screen Type and Setting,
and Security and Identification Measures
System Design - Numbers, Locations, Depths, and
| Configurations of Weils
Program Design - Sample Analysis Parameters and
Frequency, and QA/QC
Implementation Procedures - Well Installation and Sampling,
Laboratory Analysis,
and Data Evaluation
-------
Locking Cap
and Padlock
Inner Well Cap
Vent Hole
Bottom Cap
Drain Hole
Protective Casing.
Stickup
Traffic Pad.
Well Development
Borehole Diameter
Casing Diameter _
Material
Grout: Material/Mixture
Setting
Plug: Material
Setting
Sandpack: Material
Gradation
Setting
Screen: Material
Length
Type
Opening Size
Setting
Coupling
Sump Length
SUMMARY OF SPECIFICATIONS FOR
SHALLOW WELL COMPLETION
-------
Combining Direct and Indirect Data
Data for System Design
Number of Wells - Objectives of Monitoring System
Existing Records and Data
Weil Locations - Objectives of Monitoring System
Existing Records and Data
Aerial Photographs
Environmental Surveys
Geophysics
Soil Gas Survey
Site Access
-------
Combining Direct and Indirect Data
Data for System Design (Continued)
Well Depths - Objectives of Monitoring System
Existing Records and Data
Geophysics
Soil and Rock Samples
Hydrologic Measurements
Well Configurations - Objectives of Monitoring System
Existing Records and Data
Geophysics
Soil and Rock Samples
Hydrologic Measurements
-------
Selecting Well Locations
Aerial Photographs: Stressed Vegetation
Fracture Traces
Geomorphic Anomalies
Environmentai Surveys: Existing Well Contamination
Spring Contamination
Surface Water Contamination
-------
Selecting Well Locations
Geophysics: EM Anomalies
"Hard-Target" Anomalies
"Soft-Target" Anomalies
Other Factors: Objectives of Monitoring System
Existing Records and Data
Soil-Gas Anomalies
Access and Clearance
Contaminant Geochemistry
-------
Low Permeability
Clay
Sandy Zones
in Clay — —
Sand
Flow
Source Repa and Kufs, 1985
ExampBe of a Situation in Which
Different Groundwater Flow Directions
and Geologic Heterogeneities Can
nf uence the Men toring System Des cgn
-------
Selecting Well Depths
Environmental Surveys: Depth to Water in Existing Wells
Elevations of Surface
Waters and Springs
Geophysics: Stratigraphy (From 6PR, Seismic, or
Resistivity Surveys)
Depth-to-Water Estimates
Direct Data: Soil and Rock Samples
Hydrologic Measurements
Other Factors: Objectives of Monitoring System
Existing Records and Data
Contaminant Geochemistry
-------
M
I
*
M
U^y*v v
^ i Q-f V«*. i j,
Water
Table
Silty Sand
i
Clayey Silt
Gravel
.1
JtJ \ 1C£
Clay
+
+
+•
+• +¦
Impermeable
Bedrock
+¦ + +
+
4
4-
+
+
+
+
+
"t
f
+
+
+
+
+ + + 4 ~h +
+ + + 4- + +
Source Repa and Kufs, 1985
Example of a Situation in Which
Geologic Units of Different Hydraulic
Conductivities Can Influence the
Design of a Monitoring System
-------
Selecting Well Configurations
• Objectives of Monitoring System
• Existing Records and Data
& • Contaminant Geochemistry
• Stratigraphy and Hydrogeology
-------
Single
Zone
Well
Fully
Screened
Well
Multiple
Sampling
Point
Well
Single
Borehole
Well Nest
Multiple
Borehole
Well Nest
Grout
S Seal
Gravel
jS Pack
TTTTTt
777vc* 77™rv^
r;
777rn—77y^\ tttvv ttfs,
Source Repa and Kufs, 1985
WeBI Configurations Used
for Groundwater Monitoring
-------
Permeable Sandstone
Bedding Plane
^ Leakage
Well Cemented
Sandstone
Limestone
.'J.1.1.1.
ermeable Sandstone
Shales
jp®n»ieab/e
Faun
Zone
Semi-Permeable
Siltstone
Permeable
Sandstone
b e"c«
'eh
+ ,
££/+ , + +
Kt"s. »9a5
-------
waste
Disposal
Site
Artificial
LEGEND
OUncontaminated Private Wells
Contaminated Private Wells
Contaminated Industrial Well
Source. Repa and Kufs, 1985
Result of Sampling Existing WeSSs
at a Hypothetical Site
-------
Artificial
Lake
Water
Table
River
After Repa and Kufs, 1985
Example of a Situation in Which
Well Construction and Depth Influence
the Pattern of Contamination
-------
Artificial
Lake
Water
fable"
River
After: Repa and Kufs, 1985
Example of a Situation in Which
WelS Depth Influences
the Pattern of Contaminat'on
-------
Artificial
Lake
Spring
River
After: Repa and Kufs, 198S
Example of a Situation in Which
Different Water-Bearing Zones
Influence the Pattern of Contamination
-------
Artificial
Lake
Water
\
<>/j
River
After: Repa and Kufs, 1985
Example of a Situation in Which
Rock Structure and Well Depth
Influence the Pattern of Contamination
-------
Artificial
Lake
Water
Table"
River
After: Repa and Kufs, 1985
Example ©f a Situation in Which
Rook Faylts andl Fractures influence
the Pattern ©f C©ntam'nat~©n
-------
Artificial
Water
Table
River
After: Repa and Kufs, 1985
Example of a Situation in Which
Contaminant Solubility and Density
Influence the Pattern of Contamination
-------
Result of Environmental Survey
M
I
01
W
Outcrop of
Fractured
Shale
Mature
Forest
Waste
° Disposal
Site
Leachate Seep
and Contaminated
Lake Sediment
Legend
KV1 Areas of Dead Vegetation
After: Repa and Kufs, 1985
-------
Monitoring System for
Assessing Groundwater Quality
Shale
Outcrop
Lake
Waste
Disposal
Site
IS
All Wells Screened in
Silty Sand Above
Fractured Shale Bedrock
After: Repa and Kufs, 1985
-------
Result of Fracture-Trace Analysis
(>>
Shale
Outcrop
Lake
Waste
Disposal
Site
After: Repa and Kufs, 1985
-------
Result ©f GPR Survey
$yp@rimp@s©ci on a
Cross Section of the Site
^ 1^1^-
L k. v, ^ ,VW^^v VifrUM
' ,,, ^
'"^W V ';, , • «W'"' t%U^''%+*i>m.'&?-
J )&>¦$&$
*\>. •,##M'.v -y
^V*V4^. .*
tju&-
'$?A JiiT j!^'y^7'S.'-i:\
After: Repa and Kuls, 1985
-------
Result of Soil-Gas Survey
rry-
7HVJ
^ ^ ^ €*-_ 5 ^ ^
7 n~
vy ,
S W,
o
Shale
Outcrop
a 5»
aste
isposal
Legend
# 5 Existing Monitor Wells
O 18 Proposed Borings
After: Repa and Kufs, 1985
-------
Mon'tor'ng System for
Assessing Extent of Contamination
Shale
Outcrop
Lake
Waste
Disposal
Site
c «¦>.
Legend
# 5 Existing Overburden Monitor Wells
O 18 Completed Soil Borings
~ 10 Proposed Overburden Monitor Wells
¦ 4 Proposed Bedrock Monitor Wells
After: Repa and Kufs, 1985
-------
Sandstone
Shale
Sandstone
Sand-
stone
Overburden-
Leachate
Plume
Lake
Waste
Disposal
Site
Contaminated
Seep
Bedrock
Leachate
Plumes
Source Repa and Kufs, 1985
Example of the Effects of Site Geology
on Leachate PSyme Movement (Map view)
-------
~ — —V~_ _Water Table
Flow
Seep
Overland Flow
Overburden
Lake
Sand-
Stone
Shale
Shale
Sandstone
Sandstone
Source Repa and Kufs, 1985
ExampBe of the Effects of Site Geology
on Leachate Plume Movement
(Cross Sectional View)
-------
Problems in
Monitoring System Design
Planning Problems
• Wells Not Positioned Appropriately
• Screen Lengths Not Correctly Selected
• Periodic Flow Changes Not Addressed
-------
Problems in
Monitoring System Design
Implementation Problems
• Screen Setting Not Correct
• Well Silts up After Installation
• Gravel Pack Clogged
• Well Seals Leak
• Well Construction Not Documented Adequately
-------
Problems in
Monitoring System Design
Site Condition Problems
• Well Does Mot Produce
8 ® Water Table Fluctuates Greatly
« Pumping Wells Disrupt Flow Patterns
• Undocumented Waste Sources Confound Results
-------
Recharge
Area
Waste Site
Water
Table
Water Table Mound Beneath Waste Sites
Waste
Site
Permeable
Alluvium
Shale
Aquitard
Source: Repa and Kufs, 1985
ExampSe of a Situation m Which l^ulf iple
Waste Sources Cmn 8nf§u@nc@ Honiforing
System Results
-------
Problems in
Monitoring System Design
Special Problems
• Irregularly Shaped Aquifers
• Fracture Flow
• Aquifer-Contaminant Interactions
• Non-Aqueous Phase Liquids
-------
Water Table
Flow
Sand
Plume
Flow
Clay
Source Repa and Kufs, 1985
Example of a Situation in Which
High-Density NAPLs Could Migrate Against
the Direction of Groundwater Flow
-------
Problems in
Monitoring System Design
Special Problems
• Irregularly Shaped Aquifers
M
i
* • Fracture Flow
• Aquifer-Contaminant Interactions
• Non-Aqueous Phase Liquids
-------
Problems in
Monitoring System Design
Approaches to Irregularly Shaped Aquifers
• Evaluate Aquifer Geometry and Thickness
w Using Background Information; GPR, Seismic,
S and Resistivity Surveys; and Soil Borings
• install Monitoring System in Phases
• Conduct Pump Tests to Identify Boundaries
• Install Additional Wells as Appropriate
-------
Problems in
Monitoring System Design
Approaches to Contaminant Flow Through Fractures
• Evaluate Fracture Patterns Using Background
Information; Aerial Photographs;
Measurements of Outcrops and Cores; and Seismic,
GPR or Borehole Geophysical Surveys
• Install Monitoring System in Phases
• Conduct Appropriate Aquifer Tests
• Conduct Chemical Tracer Tests
• Install Additional Wells as Appropriate
-------
Problems in
Monitoring System Design
Approaches to Aquifer-Contaminant Interactions
• Evaluate Contaminant and Site Geochemistry
Using Background Information
• Install Monitoring System in Phases
• Conduct Laboratory and Field Studies as Appropriate
• Use Theoretical or Statistical Models to
Evaluate Monitoring System Data
• Install Additional Wells as Appropriate
-------
Problems in
Monitoring System Design
Approaches to Non-Aqueous Phase Liquids
• Low-Density NAPLs: Use Soil-Gas Surveys
Soil Borings and Methods for
Mapping Water Table Surfaces
• High-Density NAPLs: Use GPR, Seismic, and Resistivity
Surveys and Borings to
Map Site Stratigraphy
• Install Monitoring System in Phases
• Install Additional Wells as Appropriate
-------
MONITORING SYSTEM INSTALLATION
• DATA OBJECTIVES
• WELL DESIGN CONTROLS
• CONSTRUCTION METHODS
• WELL CONSTRUCTION MATERIALS
• INSTALLATION EXAMPLES
DATA OBJECTIVES
HYDRAULIC PARAMETERS
WATER-LEVEL DATA
WATER-QUALITY DATA
HYDRAULIC PARAMETERS
• HYDRAULIC CONDUCTIVITY (K)
• TRANSMISSIVITY (T) AND STORATIVITY (S)
• HOMOGENIETY/BARRIERS
• LEAKANCE
K-TEST DESIGN CONSIDERATIONS
• ISOLATE TEST ZONE
• DEVELOP ZONE AND PACK
• SCREEN DESIGN ALLOWS ADEQUATE FLOW
• COMPATIBLE WITH OTHER USES
'3-1
-------
PUMPING TEST DESIGN CONSIDERATIONS
• PUMPING WELL
• OBSERVATION WELL
PUMPING WELL
• ONE WELL
• FULLY PENETRATING SCREEN
• LARGE DIAMETER
• STEEL OR PVC
• WRAPPED SCREEN
• MINIMAL OTHER USES
OBSERVATION WELL
• SEVERAL WELLS
• SCREEN SAME INTERVAL AS PUMPING WELL
• STEEL OR PVC
• MINIMAL OTHER USES
HOMOGENIETY/BARRIERS
• MODIFIED PROCEDURES FOR TRANSMISSIVITY TESTS
• MAY REQUIRE MORE OBSERVATION WELLS
3-2
-------
LEAKANCE
• MODIFIED PROCEDURES FOR TRANSMISSIVITY TESTS
• VERTICAL FLOW
• SHORT SCREENS ADEQUATE
• WELL NESTS/CLUSTERS
• COMPATIBLE WITH OTHER USES
WATER-LEVEL DATA
• TYPES OF WATER LEVEL MEASUREMENTS
• LEVEL MEASUREMENT DESIGN CONSIDERATIONS
LEVEL MEASUREMENT DESIGN CONSIDERATIONS
• DIAMETER OF MEASURING DEVICE
• ISOLATE SCREEN ZONE
• CLUSTERS
• DRILLED WELLS OR DRIVE POINTS
• SURVEYING IMPORTANT
• COMPATIBLE WITH OTHER USES
WATER-QUALITY DATA
• PURPOSE FOR COLLECTING WATER-QUALITY DATA
• METHODS OF COLLECTING WATER-QUALITY DATA
3-3
-------
PURPOSE FOR COLLECTING WATER-QUALITY DATA
• IDENTIFICATION/DETECTION
• CONFIRMATION/ASSESSMENT
• COMPLIANCE/INVESTIGATION
METHODS OF COLLECTING WATER-QUALITY DATA
• WELLS
• LYSIMETERS
• "BARCAD" SAMPLERS
WELL DESIGN CONTROLS
• PLAN OBJECTIVE
• REGULATORY CRITERIA
• GEOLOGIC ENVIRONMENT
• CONTAMINANT CHARACTERISTICS
• OTHER CONSIDERATIONS IN WELL DESIGN
• EXAMPLE DESIGNS
PLAN OBJECTIVE
• HYDRAULIC PARAMETERS
• WATER-LEVEL DATA
• WATER-QUALITY DATA
• MULITIPLE PURPOSES
3-4
-------
REGULATORY CRITERIA
• WELL CONSTRUCTION METHODS
• WELL SIZE
• ANNULUSSEALS
• MATERIAL TYPES
GEOLOGIC ENVIRONMENT
• LITHOLOGY
• DEPTH
• MULITPLE AQUIFER
CONTAMINANT CHARACTERISTICS
• IMMISCIBLE ORGANICS
• DISSOLVED CONSTITUENTS
• SORPTION/DESORPTION WITH WELL MATERIALS
OTHER CONSIDERATIONS IN WELL DESIGN
• BOREHOLE SIZE
• MONITORING DEVICE (PUMP)
• DEPTH
• DRILLING METHOD
• MULTIPLE CASINGS
EXAMPLE DESIGNS
¦ UNCONSOLIDATED MATERIAL
• HARD ROCK
• MULTLPLE CASED
• WELL NESTS/WELL CLUSTERS
• LONG VS SHORT SCREENS
3-5
-------
PROTECTIVE
CASING
GROUT
JOINT
CASING
PLUG
ARTIFICIAL
FILTER PACK
WELL SCREEN
SCHEMATIC DIAGRAM
ARTIFICIAL PACK WELL
PROTECTIVE
COVER
GROUT
'JOINT
CASING
PLUG
SCREEN
SCHEMATIC DIAGRAM
NATURALLY PACKED WELL
3-6
-------
GROUT;
-PROTECTIVE
CASING
-CASING:'
MECHANICAL"
PACKER
< OPEN HOLE ¦'
SCHEMATIC DIAGRAM-
OPEN HOLE CONSTRUCTION
PROTECTIVE
CASING
i INTERMEDIATE
.'i CASING
JOINT
GROUT
CASING
; |
""""^WdHANib'AL:i$:
S:;5 PLUG KH
,... ~PLUG^^^^
V^o * Go* 'C
b qO>Q'» ; (aoq-o .b? •
*7 ARTIFICIAL PACKy«C
. c~\^\ r\-> . ¦ o° oq^*
e- SCREEN o.o A°Cvof7
? °h • . o • 0*0* o°
,;a<3°.o .;Ci°QoQ-0 -o';
OrS?.-
SCHEMATIC DIAGRAM—
MULTIPLE-CASED WELL
3-7
-------
CLUSTER NEST
1
>
i
i
i
$
SH
• • 1%. *•'
¦ :
.......
-
¦¦'•V
-
=
.«
r
*
s
^PLUG i
1
SCHEMATIC DIAGRAM-
LONG vs. SHORT SCREENS
CONSTRUCTION METHODS
• COMMON WELL DRILLING METHODS
• APPLICATION
• CABLE TOOL
• ROTARY (ALL FLUIDS)
• AUGERS
COMMON WELL DRILLING METHODS
• CABLE TOOL
• ROTARY
• AUGER
3-8
-------
APPLICATION
• GEOLOGIC FORMATION
• COMPATIBILITY WITH WELL CONSTRUCTION TECHNIQUES
• SITE CONDITIONS
• IDENTIFICAI ION/SAMPLING OF FORMATION AND AQUIFER
• RATE OF PENETRATION
CABLE TOOL
• MECHANICS
• OPERATIONAL CHARACTERISTICS
• ADVANTAGES/DISADVANTAGES
ROTARY (ALL FLUIDS)
• MECHANICS
• OPERATIONAL CHARACTERISTICS
• ADVANTAGES/DISADVANTAGES
AUGERS
• MECHANICS
• OPERATIONAL CHARACTERISTICS
• ADVANTAGES/DISADVANTAGES
3-9
-------
WELL CONSTRUCTION MATERIALS
DRILLING FLUIDS
WELL CASING
WELL SCREENS
FILTER PACK
ANNULUS SEALERS
WELL DEVELOPMENT
ABOVE-GRADE COMPLETION
DRILLING FLUIDS
PURPOSE OF DRILLING FLUIDS
MAJOR TYPES OF DRILLING FLUIDS
PROBLEMS CAUSED BY DRILLING FLUIDS
MAJOR TYPES OF DRILLING FLUIDS
• WATER BASED DRILLING FLUIDS
• AIR BASED DRILLING FLUIDS
• OIL BASED AND OTHERS
WATER BASED DRILLING FLUIDS
CLEAN WATER
WATER WITH CLAY ADDITIVES
WATER WITH POLYMERIC ADDITIVES
WATER WITH CLAY AND POLYMER ADDITIVES
3-10
-------
AIR BASED DRILLING FLUIDS
• DRY AIR
• MIST; DROPLETS OF WATER ENTRAINED IN AIRSTREAM
• FOAM; AIR BUBBLES SURROUNDED BY SURFACTANTS
PROBLEMS CAUSED BY DRILLING FLUIDS
• EFFECTS ON SAMPLE QUALITY
• EFFECTS ON GROUTING. PACKING, ETC
• EFFECTS ON WELL DEVELOPMENT
EFFECTS ON SAMPLE QUALITY
• DILUTION
• SORPTION/DESORPTION
• REDOX CHANGE
• BACTERIOLOGICAL
• ADDITIVES
WELL CASING
• PURPOSE OF CASING
• CONSIDERATIONS IN SELECTING CASING MATERIALS
• MATERIALS USED FOR CASINGS
3-11
-------
CONSIDERATIONS IN SELECTING CASING MATERIALS
• CONTAMINANTS SAMPLED
• INERTNESS
, • STRENGTH
• INSTALLATION
¦ • COST
MATERIALS USED FOR CASINGS
• PVC (POLYVINYL CHLORIDE)
• FLUOROCARBONS
• MILD STEEL
• STAINLESS STEEL
¦ OTHERS
ADVANTAGES OF PVC
• LIGHTWEIGHT
• READILY AVAILABLE
• EXCELLENT TO GOOD FOR MANY ORGANICS AND INORGANICS
DISADVANTAGES OF PVC
• WEAKER, LESS RIGID, AND TEMPERATURE SENSITIVE
• MAY REACT WITH SOME ORGANIC COUPOUNDS
• POOR CHEMICAL RESISTANCE TO SOME ORGANIC COMPOUNDS
3-12
-------
ADVANTAGES OF FLUOROCARBONS
• LIGHT TO MODERATE WEIGHT
• HIGH IMPACT STRENGTH
• CHEMICALLY INERT TO MOST ORGANIC AND INORGANIC COMPOUNDS
DISADVANTAGES OF FLUOROCARBONS
• LOW TENSILE STRENGTH
• EXPENSIVE
• LIMITED EXPERIENCE
ADVANTAGES OF MILD STEEL
• STRONG, RIGID, NOT TEMPERATURE SENSITIVE
• READILY AVAILABLE
• EXPERIENCE IN SOME CONSTRUCTION SEGMENTS
DISADVANTAGES OF MILD STEEL
• HEAVY
• POOR RESISTANCE TO INORGANIC ACIDS
• REACTIVE WITH METALS
• CUTTING OILS
3-13
-------
ADVANTAGES OF STAINLESS STEEL
• HIGH STRENGTH
• RESISTANT TO CORROSION
• MINIMAL REACTION WITH ORGANICS
• EXPERIENCE IN SOME CONSTRUCTION SEGMENTS
DISADVANTAGES OF STAINLESS STEEL
• HEAVY
• MAY LEACH SOME METALS
• CUTTING OILS
OTHERS
• POLYPROPYLENE
• FIBERGLASS
• ABS
WELL SCREENS
• PURPOSE CF SCREENS
• CONSIDERATIONS IN SCREEN DESIGN
• SLOT SIZE
• LENGTH
• INTEGRATED WITH FILTER PACK AND DEVELOPMENT
• COMPOSITE SCREEN/CASING DESIGN
• POROUS PVC OR FLOUROCARBON
3-14
-------
CONSIDERATIONS IN SCREEN DESIGN
• MAXIMIZE RAPID SAMPLE RECOVERY
• RETAIN FILTER PACK OR NATURAL FORMATION
• SLOT OPENINGS SHOULD BE OF NON-PLUGGING DESIGN
• FACILITATE EFFECTIVE DEVELOPMENT
SLOT SIZE
• 0.006 INCHES TO 0.020 INCHES
• MAXIMIZE OPEN SPACE
• 15 TO 20 PERCENT OPEN AREA (MINIMUM)
• WRAPPED SCREENS HAVE HIGHEST PERCENTAGE OPEN SPACE
FILTER PACK
• PURPOSE OF FILTER PACK
• NATURAL FORMATION PACKED WELLS
• ARTIFICIALLY PACKED WELLS
• OPEN HOLE COMPLETION
NATURAL FORMATION PACKED WELLS
• RELIES ON NATURALLY OCCURRING FORMATION MATERIAL
• BEST IN HOMOGENEOUS FORMATIONS
• SAND AND GRAVEL SIZE AQUIFER MATERIAL
• REQUIRES EXTENSIVE DEVELOPMENT TIME •
• SLOT SIZE SHOULD MAXIMIZE RETENTION OF AQUIFER MATERIAL
3-16
-------
ARTIFICIALLY PACKED WELLS
• GEOLOGIC SETTINGS FOR ARTIFICIALLY PACKED WELLS
• DESIGN CONSIDERATIONS FOR ARTIFICIAL PACK
• FILTER SOCKS AND FILTER FABRIC
GEOLOGIC SETTINGS FOR ARTIFICIALLY PACKED WELLS
• FINED GRAINED (CLAY. SILT, ETC)
• HETEROGENEOUS UNCONSOLIDATED
• INCOMPETANT ROCK
DESIGN CONSIDERATIONS FOR ARTIFICIAL PACK
• GRAIN-SIZE DISTRIBUTION OF SCREENED ZONE
• CLEAN
• WELL-ROUNDED GRAINS
• INERT COMPOSITION
• UNIFORM SIZE
• SCREEN SLOT SIZE RETAIN HIGH PERCENTAGE OF PACK
• ANNULUS SIZE
• DRILLING METHOD
¦ EXTENT ABOVE AND BELOW SCREEN
OPEN HOLE COMPLETION
• SCREEN WITH NO PACK MATERIAL
• NO SCREEN OR PACK MATERIAL
3-10
-------
ANNULUS SEALERS
• PURPOSE OF ANNULUS SEALERS
• DESIGN CONSIDERATIONS FOR SELECTING ANNULUS SEALERS
• MATERIALS USED AS ANNULUS SEALERS
• PLUGS
• GROUTS
PURPOSE OF ANNULUS SEALERS
• PREVENT VERTICAL MIGRATION OF CONTAMINANTS
• STABLIZE BOREHOLE
• SUPPORT CASING
DESIGN CONSIDERATIONS FOR SELECTING ANNULUS SEALERS
• BOREHOLE SIZE
¦ DEPTH
• COLLAPSE STRENGTH OF CASING
• WATER OUALI1Y
• DRILLING METHOD
MATERIALS USED AS ANNULUS SEALERS
• BEN rONIl E
• CEMENT
• MECHANICAL DEVICES (PACKERS. BASKETS. CENTRAUZERS)
ADVANTAGES OF BENTONITE
• READILY AVAILABLE
• INEXPENSIVE
3-17
-------
DISADVANTAGES OF BENTONITE
• CHEMICALLY REACTIVE (METALS)
• DIFFICULT TO EVALUATE SEAL
• BONDING WITH CASING DIFFICULT
ADVANTAGES OF CEMENT
• AVAILABLE
• INEXPENSIVE
• BONDS WELL WITH CASING
• BOND CAN BE TESTED
DISADVANTAGES OF CEMENT
• CHEMICALLY REACTIVE (pH)
• EQUIPMENT INTENSIVE
• SHRINKS/CRACKS
• GEOTECH DRILLERS HAVE LITTLE EXPERIENCE
PLUGS
• PURPOSE OF PLUGS
• PLACEMENT OF PLUGS
• MATERIALS USED FOR PLUGS
MATERIALS USED FOR PLUGS
• BENTONITE
• MECHANICAL PACKERS
• SAND
3-18
-------
GROUTS
• METHODS FOR PLACEMENT OF GROUT
• MATERIALS USED AS GROUT
• GROUTING PRACTICES
GROUTING PRACTICES
• FULLY GROUTEDANNULUS
• PARTIALLY GROUTED ANNULUS
• MUUTPLE CASED WELLS
WELL DEVELOPMENT
• PURPOSE OF WELL DEVELOPMENT
• CONSIDERATIONS FOR SELECTING DEVELOPMENT METHOD
• METHODS OF WELL DEVELOPMENT
PURPOSE OF WELL DEVELOPMENT
• PRODUCE SEDIMENT FREE WATER
• MINIMIZE EFFECTS OF DRILLING FLUIDS AND BOREHOLE DAMAGE
• MAXIMIZE WELL YIELD
CONSIDERATIONS FOR SELECTING DEVELOPMENT METHOD
• WELL COMPLETION CONFIGURATION
- SLOT SIZE AND SLOT CONFIGURATION
• DRILLING FLUID USED
• TYPE OF FORMATION
• HANDLING OF DEVELOPMENT FLUIDS
3-18
-------
METHODS OF WELL DEVELOPMENT
• OVER PUMPING
• BACKWASHING
• MECHANICAL SURGING
• AIR
• JETTING
• OTHERS
ABOVE-GRADE COMPLETION
• LOCKING STEEL COVER
• GUARD POSTS
• CONCRETE PAD
• IDENTIFICATION NUMBER
• SURVEYING
LOCKING STEEL COVER
• SECURITY
• PROTECTION AGAINST IMPACTS
• WEEP HOLE
GUARD POSTS
• PROTECTION AGAINST IMPACTS
• TRIANGULAR ARRAY
• BRIGHTLY PAINTED
3-20
-------
CONCRETE PAD
• DESIGNED TO PREVENT FREEZE/THAW CRACKING
• FLAT WORKING SURFACE
IDENTIFICATION NUMBER
• EASILY VISIBLE
• INSIDE PROTECTIVE COVER
SURVEYING
• LATERAL
• VERTICAL
• MARKED MEASURING POINT
INSTALLATION EXAMPLES
• CASE 1
• CASE 2
• CASE 3
• CASE 4
3-21
-------
CASE1
GEOLOGY ,
60 FT. SAND OVER
DIPPING SHALE BEDROCK
HYDROGEOLOGY
WATER TABLE AT 20 FT.
FLOW DIRECTION SAME AS DIPPING BEDROCK
SAND K= 10-3 CM/SEC, SHALE K=10"8 CM/SEC
PLUME
INSOLUBLE IN WATER
ORGANIC COMPOUNDS
CONTAMINANTS DENSER THAN WATER
WATER
TABLE
SAND
SHALE
3-22
-------
CASE 2
GEOLOGY
25 FT. SAND OVER
15 FT. SHALE OVER
MASSIVE DOLOMITE
HYDROGEOLOGY
WATER TABLE AT 10 FT.
PIEZOMETRIC PRESSURE IN DOLOMITE IS LOWER THAN
SAND AQUIFER
FLOW DIRECTION SAME IN BOTH AQUIFERS
SAND K=10"6 CM/SEC. SHALE K=108 CM/SEC.
DOLOMITE K= 10-5 CM/SEC
PLUME
SOLUBLE IN WATER
ORGANIC AND INORGANIC COMPOUNDS
SAND
WATER
TABLE
CLAY
PIEZOMETRIC'
WATER LEVEL
DOLOMITE
3-23
-------
CASE 3
GEOLOGY
35 FT. HETEROGENOUS GLACIAL TILL OVER
5 TO 10 FT SAND AND WEATHERED-SANDSTONE OVER
SANDSTONE BEDROCK
HYDROGEOLOGY
WATER TABI EAT 10 FT
PIEZOMETRIC PRESSURE IN SANDSTONE AT 5 FT. (CONFINED)
NATURAL FLOW DIRECTION IN BOTH AQUIFERS SAME
DIRECTION
SAND&SILT LENSES&STRINGERS K=10"4 CM/SEC.
CLAY K=10-8 CM/SEC, SANDSTONE K=l&3 CM/SEC
PLUME
SOLUBLE IN WATER
INORGANIC
SOME CONTAMINANTS ARE ALSO NATURALLY OCCURING
PIEZOMETRIC
WATER LEVEL
WATER
TABLE
SANDSTONE
3-24
-------
CASE 4
GEOLOGY
30 FT WIND-BLOWN SAND OVER
70 FT. UNCONSOLIDATED SANDS AND GRAVELS OVER
10 FT WEATHERED GRANODIORITE BEDROCK (SAPROLITE) OVER
FRACTURED GRANODIORITE
HYDROGEOLOGY
DEPTH TO SATURATED PORESPACES 130 FT.
UNSATURATED VERTICAL FLOW TO 130 FT. WITH NO
INTERVENING AQUITARDS
FLOW IS MULTI-DIRECTIONAL IN FRACTURED GRANODIORITE
WITH REGIONAL FLOW UNI-DIRECTIONAL
UNCONSOLIDATED MATERIAL K=10"3 CM/SEC. FRACTURED
GRANODIORITE K=1CH CM/SEC
PLUME
SOLUBLE IN WATER
ORGANIC AND INORGANIC COMPOUNDS
SAND
PEDIMENT
WASH
FRACTURED
GRANODIORITE
TABLE
3-25
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NOT DISCUSSED IN DETAIL
• Sampling devices (materials and configuration)
© SampSe containers (materiais and configuration)
© BSanks, replicates, spikes
a Decontamination
® SampSe preservation and handling
® Documentation
® Data presentation
• FormaB QA/QC procedures
-------
NEGOTIATED TECHNOLOGYy NOTSCSENCE
® Objective
-Assure that facllites have no
deleterious effects, therefore
-analyze samples representative
f of adjacent environments, therefore
no
-assure representation by removing
errors associated with sampling, then
-evaluate deleterious effects, but
-within reasonable time and cost,
at a large number of facilities
© Requirements
-Definition of representativeness
-Identification of sources/
ranges of error
-Concentration standards,
monitoring protocols
-Informed opinion, politics,
judgement (state-of-the-practice)
-------
REPRESENTA T/VENESS
® Always requires definition of spatial and
temporal scale, and
® Can never be linked to an unequivocal
determination o? accuracy
® Therefore, there is a tendency to Identify
representativeness wrtfi
-Standard procedures
-Reproducibility of results
-------
SOURCES OF ERROR
® MateraaSs
% ftlechanisms
© Procedures
e Hyman Faylt
-------
MONITORING PROTOCOLS
II
• Constituents/Properties to be Analyzed
-From indicator to complete
• Frequency of AnaByses
-Trading space for time
i
CJl
• Purpose of Analyses
-Detection
-Assessment
-Compliance
-Performance
-Corrective Action
-------
CONCENTRATION STANDARDS
« SDWA
-P»
I
O
® Clean Water Act
• State Requirements
® Cancer Risk LeveBs
© Alternate Concentration Limits
® Background
-------
BASIC SAMPLING STEPS
® Measure fluid level (s)
© Defect/sample immiscibles
-p*
i
® Purge weBB
© Measure fieicB parameters
• Obtain sample
-------
SAMPLE COLLECTION TRAIN
pH
Eh
CONDUCTANCE
TEMPERATURE
VALVE
PUMP
DISCHARGE
-Pa
\
00
VALVE
FLOWMETER
ELECTRODE
CELL
FILTER
PHOTOIONIZATION
DETECTOR OR OVA;
DISCHARGE OR
COLLECT, ANALYZE.
TREAT
METALS,
ORGANICS
ALKALINITY,
METALS
-------
SOURCES OF UNCERTAINTY
• What is being sampled?
® Where and when §s it from ?
i
® What happens when the sampling
device is introduced/activated ?
® What happens as/after the
sample leaves the well?
-------
CHEMICAL COMPOSITIONS OF DRILLING ADDITIVES
(From Brobst and Bubka, 1986)
I
Bentonite Approximate Percent
-Montmorillonite 85
-Si02 7
-K,Na,Ca-Aluminosilicates 5
-lllite 2
-CaCQ3 0.5
-CaS04-2H20 0.5
-Sodium Polyacrylate °-01
Guar Bean
-Galactomannan ®
-Water 11
-Protein 4
-Fiber 3
-Ash X_
-Fat °-5
-Methyl Blue 0.1
-------
EFFECTS OF DRILLING FLUID
ON SAMPLE CHEMISTRY
(From Groundwater and Wells, 1986)
10 20 30 40 50
Days after installation
(a) Undeveloped
100
80
60
40
20
0
COD
I \
CI
1 ¦¦""N
50 100 150
Days after installation
200
(b) Developed
-------
RECOMMENDED MATERIALS
(From Barcelona et. al., 1984)
.1) Fluorocarbon Resins (e.g., Teflon TM)
2) Stainless Steel (316, 304)
3) Polypropylene
4) Polyethylene
5) Linear Polyethylene
6) Viton ™
7) Conventional Polyethylene
8) PVC
-------
SAMPLE CONTACT RATES (0.4 GPM)
(From Barcelona et. al., 1985)
AQUIFER
MATERIAL SOLIDS (SAND) WELL (21 TUBING (1/4")
I—»
u>
CONTACT 66 0.72 4.0
RATE (M2/HR)
RELATIVE % 92 1 6
CONTACT
-------
PERCENT OF AQUIFER WATER
VERSUS TIME FOR DIFFERENT
TRANSMISSIVITIES
(From Gibb et. al., 1981)
100
60
u.
40
cc
Q = 500 mL/min
DIAMETER = 5.08 cm
30
25
TIME, minutes
-------
CRITICAL PURGE TIMES (21
DRAWDOWN (FT)
0.1 1 10 100 1,000
10 2
1,000
Ui
t 100
10-1 Q
N
U.
LLI
GO
10
103 104
PURGE RATE/TRANSMISSIVITY (FT)
-------
PACKER ISOLATION OF PUMP
COMPRESSED
GAS
HOIST CABLE
COMPRESSED—
GAS
SAMPLE
DISCHARGE
WELL
RISER
INFLATABLE
PACKER
SAMPLING
PUMP
WELL-
SCREEN
NOT TO SCALE
4-16
-------
DISTANCE OF DRAW VS. PUMP AGE
PUMP RATE
TRANSMISSIVITY
0 5 10 50 100 500 1000
PUMPAGE (GALLONS)
-------
COMPUTED TRA VEL TIMES (YEARS)
IN THE VICINITY OF PUMPING WELLS
"o]r
o o e
Drfaml
1 = 2 3
e /
4-18
-------
-p»
t
I—»
SIGNIFICANT GASES
® Carbon Dioxide (pH)
• Oxygen (Eh)
• Volatile Organics
• Hydrogen Sulfide
• Methane
-------
STABILITY OF IRON SPECIES
(After Garrels and Christ, 1965)
FeC03
Fe3C>4
2 4 6 8 10 12
pH
4-20
-------
PURGE PARAMETERS
pH Eh
A
10 +300
9 +200
8 +100
I
7 0
6 -100
5 -200
4 -300
COND TEMP
Km^ms
1
T"—t
T
7
I I
T
9
500
400
300
200
20
15
10
100 5
rJ
10
WELL VOLUMES PURGED
-------
PURGE PARAMETERS
r IWHlBaiMMIi^ '^mmnuMiKiaig^^
pH Eh
COND TEMP
10 +300
9 +200
-t^
i
ro
ro
8 +100
7 0
6 -100
5 -200
4 -300
4 5 6
WELL VOLUMES PURGED
100 5
-------
STABILITY OF IRON SPECIES
(After Garrets and Christ, 1965)
0.8'
0.6'
0.4-
0.2-
Eh (v) 0-
-0.2-
-0.4-
-0.6-
-0.8-
J
FeC03
PH
4-23
-------
CHEMICAL EFFECTS OF PURGING
32-
POTASSIUM*
E
Z
o
I-
<
cc
I-
z
UJ
o
z
o
o
MAGNESIUM
RON
J
MANGANESE
WELL VOLUMES
4-24
-------
MAJOR ION CLASSIFICATION
90
90
SULFATE
TYPE
MAGNESIUM\ If. A
TYPE V \
50
CALCIUM \
TYPE
/SODIUM OR
POTASSIUM
TYPE
CHLORIDE
TYPE
BICARBONATE
TYPE
10
10
CL"
CA
-------
LOCATION OF WASTE DISPOSAL AREAS
'AAREA D
AREA C
AREA B
055?
AREA A
FORMER
LANDFILL
-------
MAJOR ION EFFECTS
Source Waters
Downgradient Waters
Upgradient Waters
-------
COMPUTED TRIGGER LEVELS FOR 1, 2-DCE
4-jw i urn ¦ i in ||
0 20 40 60 80 100 120 140 160 180 200 220
AREA (FT2 x 103>
-------
DISTRIBUTION OF WELLS AND SOURCE AREAS
ro
UD
&
1
GRAVITY SEPARATI
SWAMP
i
-------
SAMPLE ANALYSIS
AND
QUALITY ASSURANCE
v /
COMMUNICATIONS
ANALYTICAL METHODS
QA/QC PLANS
< /
/
Communications With Lab
N
• Project Goals
• Parameters Oi Concern
• Concentrations Anticipated
• Sampling Methods And Strategy
V
y
Communications With Lab (Cont.)
Analytical Method Selection
• Regulatory Preferences
• Interferences
• Detection Limits
• Sample Containers
i >
5-1
-------
Communications With Lab (Cont.)
• Numbers of Samples
•• Replicate Samples
•• Field Blanks
• Costs
SELECTION OF ANALYTICAL METHODS
RCRA vs SUPERFUND
(
RCRA Ground Water Sample Analysis
N
• Appendix VIII
• Appendix IX
. SW 846
• Other Methods
V
J
Superfund Ground Water Sample Analysis
• Hazardous Substances List
• Contract Lab Program (CLP) Proceedures
5-2
-------
r
Quality Assurance
• Chain-of-Custody
• Quality Assessment
• Quality Control Methods
V
/
/ V
Quality Assessment
. Accuracy
- Control Samples
- Standard Reference Solutions
- Spikes
- Internal Standards
- Audits (Performance and Systems)
. Precision
- Duplicates
V /
Quality Control Methods
• Analytical Methods
• Reagent Control
• Volumetric Glassware
• Equipment Calibration
• Blanks ¦
• Control Samples
• Duplicate Analysis
• Spike Samples
¦ Data Validation
• Glassware Cleaning
• Maintenance
• Training
^ /
5-3
-------