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This is to certify that the
thesis entitled

ESTIMATING THE NATURE AND DISTRIBUTION OF
SHALLOW SUBSURFACE PALEOSOLS ON FLUVIAL FANS
IN THE SAN JOAQUIN VALLEY, CALIFORNIA

presented by
GEORGE LUTHER BENNETT V

has been accepted towards fulfillment
of the requirements for the

Master of degree in Geology
Science

£922, 44M

Major Professor’s Signature
I 3 NOWLU‘ 2-003

Date

 

 

 

 

 

MSU is an Affinnative Action/Equal Opportunity Institution

 

 

LIBRARY
Mlchigan State
University

 

 

 

PLACE IN RETURN BOX to remove this checkout from your record.
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6/01 c:/ClRC/DateDue.p65-pr15

ESTIMATING
PALEOSOLS (

ESTIMATING THE NATURE AND DISTRIBUTION OF SHALLOW SUBSURFACE
PALEOSOLS ON FLUVIAL FANS IN THE SAN JOAQUIN VALLEY, CALIFORNIA

By

George Luther Bennett V

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE

Department of Geology

2003

 

ESTIMATING T
PALEOSOLS O.‘

Flutial l“.
sediment scqucr
eta]. 3002). Th:
pedogenically a
beliel'cd to be I
and I) continm
during glacial l
tIIEKI'ngs, Me
is a regionall}
Paleochannel
Idfntified in 1

CLIIIcrem film

 

1-"

ABSTRACT

ESTIMATING THE NATURE AND DISTRIBUTION OF SHALLOW SUBSURFACE
PALEOSOLS ON FLUVIAL FANS IN THE SAN JOAQUIN VALLEY, CALIFORNIA

By

George Luther Bennett V

Fluvial fans in the San Joaquin Valley, California are composed of multiple
sediment sequences separated by unconformable surfaces (Weissmann, 1999; Weissmann
et a1. 2002). The individual sequences are composed of channel, overbank, and
pedogenically altered sediments. The pedogenically-altered deposits (paleosols) are
believed to be 1) laterally continuous sequence stratigraphic bounding unconfonnities
and 2) continuous with the exception of discrete breaks caused by paleochannel activity
during glacial times. Using ground-penetrating radar and digitized county soil surveys on
the Kings, Merced, and Tuolumne River fluvial fans we show that the Riverbank paleosol
is a regionally laterally continuous feature and that discrete erosional breaks due to
paleochannel activity do exist in the Kings River fluvial fan. Erosional breaks were not
identified in the Merced or Tuolumne River fluvial fans. It is believed that a number of
different factors including, basinal subsidence differences, stream base-level, Sierran
drainage area, and sediment supply play a role in the morphological differences observed

between the Kings, Merced, and Tuolumne River fluvial fans.

This rcsca
Chemical Socicn
Baker and the get
and data pI'OVILICK
the work done at
possible without
of Geological St
thml Karen Bu:
I'SGS whom I ‘
this project. C o
it. the understai

lWBht
L1ndphlflliimnt:
keep. me moth
Hm SO many \
here. Yet fort
Iain now. 1 ~
sl
irate ahVayg 7

Norm f0r he

ACKNOWLEDGMENTS

This research was supported by the Petroleum Research Fund, American
Chemical Society (PRF #3 7731-G8). I benefited greatly from discussions with Greg
Baker and the geophysics students at SUNY, Buffalo. In addition, conversations with,
and data provided by Thomas Harter and Sevim Onsoy greatly improved the caliber of
the work done at the Kearney Agricultural Center. Also, this work would not have been
possible without the GPR equipment provided by Dr. Detlef Wamke and the Department
of Geological Sciences, California State University, Hayward. Lastly, I would like to
thank Karen Burrow, Barbara Dawson, Jill Judy-Densmore, and Mike Wright of the
USGS whom I worked with during an internship following the GPR data collection for
this project. Conversations with and data provided by Karen Burrow and the USGS aided
in the understanding of this work.

I wish to sincerely thank my thesis committee, Gary Weissmann, Dave Hyndman,
and Phanikumar Mantha. Their enthusiasm for this project, especially Gary’s, helped to
keep me motivated while slogging through our enormous data set. I feel blessed to have
met so many wonderful people here at MSU that I regret I am unable to mention them all
here. Yet for those of you who read this, know that in some way you helped me get where
I am now. I should also acknowledge our office staff, Loretta, Cathy, and Jackie, who
were always helpful and supportive. Last, but by no means least, I wish to thank Sarah

Norris for her never-ending support.

iii

usr or TABII
usr or FIGL R

CHM ER 03"
INTRODI'CT
THESIS HYI’
METHODS
STUDY ARE
SEQI'ENC E I
THESIS OL'T

CHAPTER T“

INTRODI'CT
STUDY ARI
SEQI’EX CE
GPR TI IEOR
GPR .\IETI It
GPR RESI'L
OBSERVE D
CONCLL'SII

(INTER Tl

OTHER GPI
IESTS AT T

Kearney ,1
GPR METII

GPR Prof
RADAR E..\
PALEOSQ L
PALEosoL
CONCLLD]

v

TABLE OF CONTENTS

 

 

 

 

 

LIST OF TABLES ................................................................................... vi
LIST OF FIGURES ................................................................................. vii
CHAPTER ONE 1
INTRODUCTION .......................................................................................................... l
THESIS HYPOTHESES ................................................................................................ 3
METHODS ..................................................................................................................... 3
STUDY AREA ............................................................................................................... 6
SEQUENCE STRATIGRAPHY .................................................................................... 8
THESIS OUTLINE ....................................................................................................... 12
CHAPTER TWO - - - - 14
INTRODUCTION ........................................................................................................ 14
STUDY AREA ............................................................................................................. 15
SEQUENCE STRATIGRAPHY OF FLUVIAL FAN DEPOSITS ............................. 17
GPR THEORY .............................................................................................................. 21
GPR METHODOLOGY ............................................................................................... 24
GPR RESULTS ............................................................................................................ 26
OBSERVED DIFFERENCES BETWEEN THE KRF AND TRF .............................. 31
CONCLUSIONS ........................................................................................................... 33
CHAPTER THREE -- - - 35
OTHER GPR OBSERVATIONS ................................................................................. 35
TESTS AT THE KEARNEY AGRICULTURAL CENTER ....................................... 35
Kearney Agricultural Center: Radar F acies ........................................................... 3 7
GPR METHODOLOGY ............................................................................................... 4O
GPR Profiles: Descriptions of Radar F acies .......................................................... 42
RADAR FACIES CONCLUSIONS ............................................................................. 45
PALEOSOL GROUNDTRUTH AT THE KAC .......................................................... 46
PALEOSOL TOPOGRAPHY ...................................................................................... 47
CONCLUDING REMARKS FOR FUTURE WORK ON RADAR FACIES ............. 48
OUR ATTEMPT AT USING MATLAB TO PICK PALEOSOLS AND
ASSOCIATED EROSIONAL BREAKS ..................................................................... 49
CHAPTER FOUR - 52
PALEOSOLS AS REGIONALLY LATERALLY CONTINUOUS FEATURES ...... 52
EROSIONAL BREAKS IN THE LATERALLY CONTINUOUS PALEOSOLS ...... 52
RADAR FACIES AT THE KEARNEY AGRICULTURAL CENTER ...................... 53
PALEOSOL GROUNDTRUTH INFORMATION ...................................................... 54
COMPARE AND CONTRAST BETWEEN THE THREE FLUVIAL FANS ........... 55
FUTURE CONSIDERATIONS ................................................................................... 56
APPENDIX A 58
KINGS RIVER FLUVIAL FAN GPR PROFILES .................................................................. 59
TUOLUMNE AND MERCED RIVER FLUVIAL FAN GPR PROFILES .................................. 102

iv

 

APPENDIX B .....

KEARNEY ORCII
503le Y-DIRIL
Sill-1H2 X-DIRP
100MHz \'-I)IR
100MHz X-DIR

APPENDIX C

CMP EXPERNI
CMP LOCATIO‘.

APPENDIX D

GPR SYSTEM (
STEPS TO SIiTI
C0.\l.\l0\ PRI )I
Skipped Tra
Dos Mode v
GPR DATA PR
GPR DATA .~\\

APPENDIX E ..

MATLAB SC
Point Def”;
GPR.’ SCH]

REFERENCES

 

APPENDIXB -- - - 127

 

 

 

 

 

KEARNEY ORCHARD SITE GPR PROFILES ................................................................... 128
SOMHZ Y-DIRECTION PROFILES .................................................................................. 129
50MHZ X-DIRECTION PROFILES .................................................................................. 132
100MHz Y-DIRECTION PROFILES ................................................................................ 136
100MHz X-DIRECTION PROFILES ................................................................................ 139
APPENDIX C -- - -- - - .......... -- 143
CMP EXPERIMENTS ..................................................................................................... 144
CMP LOCATION MAPS ................................................................................................ 149
APPENDIX D - - - - _ 151
GPR SYSTEM COMPONENTS ........................................................................................ 152
STEPS TO SETUP GPR SYSTEM .................................................................................... 152
COMMON PROBLEMS ................................................................................................... 153
Skipped Traces ....................................................................................................... 153
Dos Mode vs. Windows Environment ................................................................... 1 5 4
GPR DATA PROCESSING .............................................................................................. 154
GPR DATA ANALYSIS ................................................................................................. 155
APPENDIX E - _ - -_ -- 156
MATLAB SCRIPTS ................................................................................................... 157
Point Define Auto Script ........................................................................................ I 5 7
GPRZ Script ............................................................................................................ 1 60
REFERENCES--.---- - - - -- -_ - _- _ 164
V

Table ll Approxim.
materials. I Data tron

Table Cl Table listii
and location in chr

 

 

LIST OF TABLES

Table 2.1 Approximate values of conductivity and relative dielectric permittivity for selected
materials. (Data from Ulriksen, 1982). Modified from Beres & Haeni (1991). ............................ 23

Table Cl Table listing all CMP experiments by name as well as calculated near surface velocity
and location in Degrees Decimal Minutes ................................................................................... 144

vi

Figure 1.] Ground r
console. laptop com
and 100 MHZ anten'
rechargeable 6-\' ba
charge. while doing

Figure l2 C-horizo
paleochannel locatii

Figure 1.3 Location
abandoned paleoeh;
30m Digital Elex'ati

Figure l.~’l Sequene
AI Ion aceumulati
Decrease in aeeumi

Figurel S SITBIIL’I’
l°8815homng the
lleissmann et al (.

Figure l 6 Accumi
{WIVES (\Iodiliet

Figure- ‘ .1 Stud) 3

uolumne Rix er II
tletation mOde ,5]

LIEWOI On the TR}

Elam-e ‘1“) Sequen
acaIXIOdlfied

LIST OF FIGURES

(Images in this thesis are presented in color.)

Figure 1.1 Ground penetrating radar system field setup in profiling mode. The system includes a
console, laptop computer, 12-V battery power source (all located in car), and interchangeable 50
and 100 MHz antennae (50 MHz attached in photo). The GPR antennae were powered using two
rechargeable 6-V batteries (chargers in trunk of car). Operational life of the batteries at full
charge, while doing long profiles (km length) averaged approximately 45 minutes. ..................... 4

Figure 1.2 C-horizon texture map of the upper KRF. Dotted lines indicate interpreted
paleochannel locations. (Map modified from Huntington, 1971). .................................................. 5

Figure 1.3 Locations of KRF, TRF and MRF within the San Joaquin Valley of California. (Note
abandoned paleochannels visible on KRF digital elevation model) Background map are USGS
30m Digital Elevation Models ......................................................................................................... 7

Figure 1.4 Sequence stratigraphic cycles on the KRF as interpreted by Weissmann et al. (2002).
A) Low accumulation space. B) Increase in accumulation space. C) High accumulation space. D)
Decrease in accumulation space. (Modified from Weissmann et al. 2002) .................................... 9

Figure 1.5 Stratigraphic column for the KRF (based on Marchand and Allwardt, 1981; Lettis
1988) showing the five “sequences” described by Weissmann et al. 2002. (Modified from
Weissmann et al. (2002)) ............................................................................................................... 10

Figure 1.6 Accumulation space on fluvial fans relative to the fluvial fan surface and other fan
features. (Modified from Weissmann et al. (2002)) ...................................................................... 1 I

Figure 2.1 Study area location map, highlighting the locations of the Kings River fluvial fan,
Tuolumne River fluvial fan, and the Merced River fluvial fan. Images of fans are 30m digital
elevation models from the USGS. Note highly visible abandoned channels on KRF, and lack
thereof on the TRF and MRF. ....................................................................................................... 16

Figure 2.2 Sequence stratigraphic depositional cycle on the KRF as proposed by Weissmann et al.
2002a. (Modified from Weissmann et al., 2002a) ......................................................................... 18

Figure 2.3 Stratigraphic column for the eastern San Joaquin Valley Quaternary deposits based on
Marchand & Allwardt, (1981) and Lettis, (1988). (Modified from Weissmann et al., 2002a) ..... 20

Figure 2.4 Cross-section through the upper KRF. Cross-section is parallel to depositional dip and
shows the proposed laterally continuous sequence bounding paleosols. (Modified from
Weissmann et al. 2002a) ................................................................................................................ 20

Figure 2.5 A) Simplified schematic diagram of the ground penetrating radar system. (Modified
from Davis & Arman (1989)) B) Schematic procedure for GPR survey profiling, which involves
repetitive moves of both the transmitter and receiver held at a constant spacing. C) Schematic
GPR traces, highlighting the arrival of the air and ground wave pulses and a reflected wave from
a subsurface reflector. ((B) & (C) Modified from Jol & Smith 1991) .......................................... 21

vii

 

  
   

Figure 2.6 A) C omn
oldie electromagnci
example ol‘a C MP I

Figure 2.7 Ground p
eoitsole. laptop com;
and 100MHz antenil
rechargeable 6-\' ba
ChllgCTIII’IIIC doing I

Figure 2.8 GPR pro:
clustered in the sout.‘
Background maps ar

Figure19 A) GPR p
exposed at the swim
beloII Modesto depo
depth. BI GPR protil
adeep paleochannel
incision ma} be the '
Stacked hyperbola o
narroII bands as obs
irrigation ditches...

 

Figure T lOA Map A
thelocation of palm
IraIIon the KRFI
II‘CIIOII'I.SI‘I£1IIO\\C
he and corrupt liI
figure is presented
Figure T 108 Map
indicate location 0
eat I on the TRF;
Ciannel Incision (I
Em highlighted
Presented In col or

Figure 3 1 \‘

Ill-m Sp SI

FI‘WUIQ 3 1 GHR

G? R
:h‘;(\\\p riOfiIIe ‘OCE:

Ure: .

mSuhO fife

Figure 2.6 A) Common Mid Point (CMP) experiment used to calculate the propagation velocity
of the electromagnetic GPR waves in the near-surface sediments (Modesto Formation). B) An
example of a CMP used to determine the near-surface sediment velocity on the KRF. ............... 23

Figure 2.7 Ground penetrating radar system field setup in profiling mode. The system includes a
console, laptop computer, 12-V battery power source (all located in car), and interchangeable 50
and 100 MHz antennae (50 MHz attached in photo). The GPR antennae were powered using two
rechargeable 6-V batteries (chargers in trunk of car). Operational life of the batteries at full
charge while doing long profiles (km length) averaged approximately 45 minutes. .................... 24

Figure 2.8 GPR profile location maps for (A) the KRF and (B) the TRF and MRF. Profiles
clustered in the southeastern portion of (B) are located on Merced River deposits (See Figure 1).
Background maps are 30m USGS seamless digital elevation models. ......................................... 25

Figure 2.9 A) GPR profile on the KRF showing the typical paleosol reflection pattern when
exposed at the surface as well as buried below Modesto deposits. Beyond 750 m paleosol is
below Modesto deposits and is expressed as the tight dark band couplet at approximately 5 m
depth. B) GPR profile on the KRF showing the typical reflection pattern observed when entering
a deep paleochannel incision as well as an area that shows shallow channel incision. Shallow
incision may be the result of lateral channel migration across the fan surface through time.
Stacked hyperbola observed on both GPR profiles represent overhead power lines, while the deep
narrow bands as observed at approximately 290 m on profile A and 380 m on profile B represent
irrigation ditches. ........................................................................................................................... 27

Figure 2.10A Map showing a portion of the upper KRF surface. C-horizon textures clearly show
the location of paleochannels (stippled pattern), overbank deposits (light gray) and hardpan (dark
gray) on the KRF. GPR profiles have been interpreted to highlight areas of deep channel incision
(yellow), shallow channel incision (green), and paleosol (red). Questionable areas highlighted in
blue and corrupt lines highlighted as black. (Soil map modified from Huntington, 1971) *This
figure is presented in color. ........................................................................................................... 28

Figure 2108 Map showing a portion of the upper TRF and MRF surfaces. C-Horizon textures
indicate location of sands (stippled pattern), overbank deposits (light gray) and hardpan (dark
gray) on the TRF and MRF. GPR profiles have been interpreted to highlight areas of deep
channel incision (yellow), shallow channel incision (green), and paleosol (red). Questionable
areas highlighted as light blue. (Soil map modified from Huntington, 1971) *This figure is
presented in color. ......................................................................................................................... 29

Figure 3.1 Map showing the location of the KAC on the KRF. Aerial photo shows location of
former nectarine Orchard Site within the KAC. (Aerial photo from www.MapQuest.com, KRF
image from 30m USGS Digital Elevation Model) ........................................................................ 36

Figure 3.2 GPR grid eStablished at the Kearney Agricultural Center Orchard Site. Lines represent
GPR profile locations, and points represent well locations. The GPR profile from line Y9] is

shown in figure 3.5, and the GPR profile from line X51 is shown in Figure 3.6. Offset in the lines
a result of field conditions and equipment setup during the time of data collection. .................... 40

Figure 3.3 Collecting GPR data in the former nectarine Orchard Site. GPR equipment attached to
the back of the tractor. ................................................................................................................... 41

viii

 

Figure 3.4 ConductI
Ioramore in depth

Flaunt 3.5 West-Em
Dotted Iellon line s
section (B) the you
Wand 46 m. A \elI-
maltsis at the KAI

Figure 3.6 South-\o
Dotted I'ellou line s
LlSCd in GPR profile

in tigure3.T. ‘Tliis i

 

Figure 3.7 Schematit
depressions in the Ht

Figure 3.8 Example
dexeloped to pick th

color.............
FrgureAl Segment
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F T
Igure A3 Segment

Fiu'
sure A4 Se gmen‘

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we A9 Stfilmei

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rig.

ire ‘Xl l D‘dF

grr
FlQI
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Fir;-
cu
. re A14 our

Figure 3.4 Conducting a CMP experiment at the KAC Orchard Site study site (See chapter two
for a more in depth description of CMP experiments). ................................................................. 42

Figure 3.5 West-East GPR profile from the Orchard Site at the KAC with described well logs.
Dotted yellow line sits on the reflector interpreted as the paleosol. Note that in the 50 MHz
section (B) the ground wave arrival is overprinting the paleosol reflection between approximately
19 and 46 m. A velocity of 0.14m/ns was used in GPR profile depth correction from CMP
analysis at the KAC. Profile locations are shown in figure 3.2. *This image is presented in color.
....................................................................................................................................................... 43

Figure 3.6 South-North GPR profile from the Orchard Site at the KAC with described well logs.
Dotted yellow line sits on the reflector interpreted as the paleosol. A velocity of 0.14 m/ns was
used in GPR profile depth correction from CMP analysis at the KAC. Profile locations are shown
in figure 3.2. *This image is presented in color. ........................................................................... 44

Figure 3.7 Schematic diagram depicting preferential recharge as a function of topographic
depressions in the near-surface paleosols on Central Valley fluvial fans. .................................... 48

Figure 3.8 Example of smoothed data plotted on top of GPR profile using the MATLAB script
developed to pick the trace values at which the signal goes to noise. *This figure presented in

color. .............................................................................................................................................. 50
Figure A1 Segments 1 & 2 of merged Smith Road profiles 34-39. .............................................. 59
Figure A2 Segment 3 of merged Smith Road profiles 34-39. ....................................................... 60
Figure A3 Segments 1 & 2 of merged Smith Road profiles 40-43. .............................................. 61
Figure A4 Segments 1 & 2 of merged Smith Road profiles 1 & 2 ................................................ 62
Figure A5 Segment 3 of merged Smith Road profiles 1 & 2. ....................................................... 63
Figure A6 Segments 1 & 2 of merged Del Rey Road profiles 11-15. ........................................... 64
Figure A7 Segments 3 & 4 of merged Del Rey Road profiles “-15. ........................................... 65
Figure A8 Segments l & 2 of merged Del Rey Road profiles 16-20. ........................................... 66
Figure A9 Segments 3 & 4 of merged Del Rey Road profiles 16-20. ........................................... 67
Figure A10 Highland Road Profile (HLl 1) ................................................................................... 68
Figure A11 Del Rey Road Merged Profiles 31-33 (100 MHz). .................................................... 69
Figure A12 Segments 1&2 of Lincoln Road Merged Profiles 11-13. ........................................... 70
Figure A13 Segments 3&4 of Lincoln Road Merged Profiles 11-13. ........................................... 71
Figure A14 Segments 5&6 of Lincoln Road Merged Profiles 11-13. ........................................... 72
Figure A15 Segments 7&8 of Lincoln Road Merged Profiles 11-13. ........................................... 73

ix

 

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Figure A16 Segment 9 of Lincoln Road Merged Profiles 11-13 ................................................... 74

Figure A17 Segments 1&2 of Bethel Road Merged Profiles 2-3. Segment two (0-660m) corrupt.

....................................................................................................................................................... 75
Figure A18 Segments 3&4 of Bethel Road Merged Profiles 2-3. ................................................. 76
Figure A19 Segment 5 of Bethel Road Merged Profiles 2-3. ....................................................... 77
Figure A20 Segments 1&2 of Dinuba Road Profile 3. .................................................................. 78
Figure A21 Segments 1&2 of North Road Profile 1. .................................................................... 79
Figure A22 Segments 3&4 of North Road Profile 1. .................................................................... 80
Figure A23 Indianola Road Profile 3. ........................................................................................... 81
Figure A24 Segments 1&2 of Annadale Road Profile 1. .............................................................. 82
Figure A25 Segments 1&2 of Green Road Merged Profiles 1-2 ................................................... 83
Figure A26 Segment3 of Green Road Merged Profiles 1-2. ......................................................... 84
Figure A27 Segments 1&2 of Highland Road Profile 1 ................................................................ 85
Figure A28 Segment 3 of Highland Road Profile 1. ..................................................................... 86
Figure A29 Central Avenue Merged Profiles 1&2. Segment 2 is corrupt ..................................... 87
Figure A30 Segments 1&2 of Butler Road Profile 1 ..................................................................... 88
Figure A31 Segments 1&2 of California Road Profile 1. ............................................................. 89
Figure A32 Church Road Profile 1 ................................................................................................ 90
Figure A33 Dockery Road Profile 1 .............................................................................................. 91
Figure A34 Segments 1&2 of Indianola Road Profile 21. ............................................................ 92
Figure A35 Thompson Road Profile 1. ......................................................................................... 93
Figure A36 Segments 1&2 of Thompson Road Profile 21 (Thom21). ......................................... 94
Figure A37 Segments 1&2 of Kamm Road Merged Profiles 1&2 ................................................ 95
Figure A38 Segments 3&4 of Kamm Road Merged Profiles 1-2. ................................................ 96
Figure A39 Segments 1&2 of Nebraska Road Merged Profiles 1-3. ............................................ 97
Figure A40 Segments 3&4 of Nebraska Road Merged Profiles 1-3. ............................................ 98
Figure A41 Segment 5 of Nebraska Road Merged Profiles 1-3. ................................................... 99

 

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Figure A42 Segments 1&2 of Zediker Road Profile 1. ............................................................... 100
Figure A43 Segments 3&4 of Zediker Road Profile 1. ............................................................... 101
Figure A44 Segments 1&2 of Bradbury Road Profile 1. ............................................................ 102
Figure A45 Segments 1&2 of Merced Road Merged Profiles 1-2. ............................................. 103
Figure A46 Segment 30f Merced Road Merged Profiles 1-2. ..................................................... 104
Figure A47 Segments 1&2 of Palm Road Merged Profiles 1-2. ................................................. 105
Figure A48 Segments 1&2 of Bloss Road Merged Profiles 1-3. ................................................ 106
Figure A49 Segment 3 of Bloss Road Merged Profiles 1-3. ....................................................... 107
Figure A50 Segments 1&2 of American Avenue Profile 1. ........................................................ 108
Figure A51 Segment 3 of American Avenue Profile 1. .............................................................. 109
Figure A52 Segments 1&2 of Pepper Road Profile 1. ................................................................ 110
Figure A53 Sunny Acres Road Profile 1. .................................................................................... 1 11
Figure A54 Segments 1&2 of Newport Road Profile 1 ............................................................... 1 12
Figure A55 Segment 3 of Newport Road Profile 1. .................................................................... 113
Figure A56 Segments 1&2 of Sperry Road Profile 1. ................................................................. l 14
Figure A57 Segments 3&4 of Sperry Road Profile 1. ................................................................. 115
Figure A58 Segments 1&2 of Grayson Road Profile 1 (Graysl). ............................................... 1 16
Figure A59 Segments 1&2 of Pioneer Road Profile 1. ............................................................... 117
Figure A60 Segment 3 of Pioneer Road Profile 1. ...................................................................... 1 18
Figure A61 Segments 1&2 of Redwood Road Profile 1. ............................................................ 1 19
Figure A62 Segments 1&2 of Monte Vista Road Profile 1. ........................................................ 120
Figure A63 Segments 3&4 of Monte Vista Road Profile 1 ......................................................... 121
Figure A64 Segments 1&2 of Mitchell Road Profile 1. .............................................................. 122
Figure A65 Segments 3&4 of Mitchell Road Profile 1. .............................................................. 123
Figure A66 Segment 5 of Mitchell Road Profile 1 ...................................................................... 124
Figure A67 Segments 1&2 of Grayson Road Profile 1 (Grsonl) ................................................ 125
xi

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used to groundtrutli

Figure B2 50} 141 I:
Figure B3 50} 121 I1
FigureB450I111 d

Figure BS 50}9l de

 

Figure 86 50} 81 9"
Figure BT’ 50.19] dcl
Figure BS 50341 de'
Figure B9 50x1 1 dc
Figure 810 50x31 d
Figure 811 50x51 d
Figure 812 50x81 d
Figure 813 50x10]
Figure 814 50.\l2l
Figure 815 50x141
Figure 8163141 de
Fl31463173121 de
Figure 818 _I‘1 11 a.

Figure 819 )9l der

Fl‘gure B:

0 )81 deg
Figure B21 I61 ch
Figure B2T _\'4l cF
Figure 823 x1 1 dc;
Figure B24 x31 dc;
Figure B25 451

Figure A68 Segment 3 of Grayson Road Profile 1 (Grsonl). ..................................................... 126

Figure B1 Kearney Agricultural Center orchard site GPR grid map. Geoprobe borehole locations

used to groundtruth the GPR data are also shown. ...................................................................... 128
Figure B2 50y141 depth section. ................................................................................................. 129
Figure B3 50y121 depth section. ................................................................................................. 129
Figure B4 50y111 depth section. ................................................................................................. 130
Figure BS 50y91 depth section. ................................................................................................... 130
Figure B6 50y81 depth section. ................................................................................................... 131
Figure B7 50y61 depth section. ................................................................................................... 131
Figure B8 50y41 depth section. ................................................................................................... 132
Figure B9 50x11 depth section. ................................................................................................... 132
Figure B10 50x31 depth section .................................................................................................. 133
Figure B11 50x51 depth section. ................................................................................................. 133
Figure BIZ 50x81 depth section. ................................................................................................. 134
Figure B13 50x10] depth section. ............................................................................................... 134
Figure 314 50x121 depth section. ............................................................................................... 135
Figure BIS 50x14] depth section. ............................................................................................... 135
Figure B16 y141 depth section. ................................................................................................... 136
Figure 817 y121 depth section. ................................................................................................... 136
Figure B18 y111 depth section. ................................................................................................... 137
Figure 819 y91 depth section. ..................................................................................................... 137
Figure 820 y81 depth section. ..................................................................................................... 138
Figure 821 y61 depth section. ..................................................................................................... 138
Figure 822 y41 depth section. ..................................................................................................... 139
Figure 823 X] 1 depth section. ..................................................................................................... 139
Figure B24 x31 depth section. ..................................................................................................... 140
Figure 325 x51 depth section. ..................................................................................................... 140

xii

Figure B26 .\81 de;
Figure B27 x101 dI.

Figure B28 x121 d.

 

Figure B29 x141 dc

Figure Cl .4 1 Del R
131110411121 D) Lines.

Figure C2A1L111CI‘
Keane} Orchard S:

Figure C3 .41 Kearn
(111’ D) Mitchel RI

Figure C4 .4) Next p

Figure C5 KRF: text
For texture map hex

Figure C6 TRF and
experiments. For tex

Figure B26 x81 depth section. ..................................................................................................... 141

Figure B27 x101 depth section. ................................................................................................... 141
Figure B28 x121 depth section. ................................................................................................... 142
Figure 329 x141 depth section. ................................................................................................... 142
Figure C1 A) Del Rey Road CMP B) Highland Road 1 CMP C) Highland Road 2 CMP
(100MHz) D) Lincoln Road 1 CMP ............................................................................................ 145
Figure C2 A) Lincoln Road 2 CMP B) Parlier Road 1 CMP (100MHz) C) Parlier Road 2 CMP D)
Kearney Orchard Site 1 CMP ...................................................................................................... 146
Figure C3 A) Kearney Orchard Site 2 CMP (100 MHz) B) Dinuba Road 2 CMP C) Bloss Road 1
CMP D) Mitchel Road 1 CMP .................................................................................................... 147
Figure C4 A) Newport Road 1 CMP B) Palm Road 1 CMP C) Redwood Road 1 CMP ............ 148

Figure C5 KRF texture map and roads coverage highlighting the locations of CMP experiments.
For texture map key see Chapter Two ......................................................................................... 149

Figure C6 TRF and MRF texture map and roads coverage highlighting the locations of CMP
experiments. For texture map key see Chapter Two. ...................................................... 150176176

xiii

 

The iluI'ic.
in the Central \' al

for irrigation and :

 

 

 

architecture contrI
shoun that the 1511
sequences separat
2002a). The 111Lll\’
IiI'eI forming the
or floodplain dep
Formation proces
et al. 2002a I. The
the unconformab
Additionally. the
aquifers since th
distributed 0Ver

)4 eiSSmann et 3]

Ground‘]

in

‘

1T .
IRF), and the ‘

[G‘Jl Till
9“ atta
sm

CHAPTER ONE

INTRODUCTION

The fluvial fans located along the western margin of the Sierra Nevada Mountains
in the Central Valley of California contain aquifers that are significant sources of water
for irrigation and municipal use. In these fluvial hydrologic systems, the sediment’s
architecture controls fluid flow. Recent work on the Kings River fluvial fan (KRF) has
shown that the typical framework for the fluvial fan deposits consists of multiple
sequences separated by unconformable surfaces (Weissmann, 1999; Weissmann et al.
2002a). The individual sequences are composed of channel sediments from the primary
river forming the fluvial fan, overbank sediments which result from levee, crevasse splay,
or floodplain deposition, and pedogenically-altered deposits, which result from soil
formation processes during times of depositional hiatus (Weissmann, 1999; Weissmann
et al. 2002a). The pedogenically-altered deposits, or paleosols (ancient soils), represent
the unconformable surface (depositional hiatus) that separates the sequences.
Additionally, they probably exert a profound control on fluid flow within the fluvial fan
aquifers since they are composed of clay rich (low conductivity) sediments and are
distributed over large areas and are acting as confining layers (Weissmann, 1999;
Weissmann et al. in press).

Ground-penetrating radar (GPR) was utilized in this study to estimate the regional
lateral continuity of the near-surface paleosols on the KRF, Tuolumne River fluvial fan
(TRF), and the Merced River fluvial fan (MRF). GPR has been shown to be an effective

tool when attempting to track the lateral extent of silt and clay layers in KRF by Burrow

etal. (1997). In ti
techniques (GPR
methods. proI'ich
timtexx'ork of the
continuity of a ne.
paleosol that reprc
al. (20023).

Additional

 

the KRF. We beli
Facies) at the Rear
Parlier. C .4 on the
m tool in facics i
lluggenberger. 19‘
GPR and a series (
Harter et al. (199‘)

et al. (1997). In their study, Burow et al. (1997) showed that surface geophysical
techniques (GPR and Seismic Reflection), combined with geologic coring and borehole
methods, provided a means to more extensively characterize the sedimentological
framework of the KRF. Using GPR, Burow et a1. ( 1997) successfully mapped the
continuity of a near-surface fine-grained layer, which we believe to be the near surface
paleosol that represents a sequence stratigraphic boundary hypothesized by Weissmann et
al. (2002a).

Additionally, we evaluated the application of GPR to recognize the radar facies in
the KRF. We believe that GPR may be used for the recognition of facies patterns (radar
facies) at the Kearney Agricultural Center (KAC), a small-scale study site southeast of
Parlier, CA on the KRF. Various studies in the past have shown the applicability of GPR
as a tool in facies interpretation (6. g. Beres & Haeni, 1991; J01 & Smith, 1991;
Huggenberger, 1993; Jakobsen & Overgaard, 2002). In this portion of the study we used
GPR and a series of closely spaced wells cored and described for a vadose zone nitrate by
Harter et a1. (1999) in an attempt to extrapolate hydrogeologic facies to a depth of 6 m
above the near surface paleosol at the Kearney Field Station.

Lastly, in attempting to evaluate the lateral extent of the near surface paleosols on
the KRF, TRF, and MRF it is observed that the near surface paleosols on the KRF and
TRF exhibit subtle topography. The implications of this observation may be of
significance when attempting to estimate the locations of significant recharge in these
fluvial aquifers. Topographic lows in the surface of this near surface confining layer may
act as groundwater collection areas (depression storage) and thus, once the hydraulic

head builds up, be the locations where water is forced through the confining layer into

 

deeper atluifCr ”1

detaining “M

The {0“th
1) Near-S
featur

3) Breaks
distrih

3) Mean ‘1
paleoc

4) GPR all
near-St
We will al:
the W TRF. ant

including. but not

and Sierran drama:

To test the l

0. .
geologic \I'ell borin

Burrow et al. ( 1997

deeper aquifer units. Future groundwater models may want to consider this when

developing future models to characterize these systems.

THESIS HY POTHESES
The following hypotheses are the primary focus of this work:
1) Near-surface paleosols on the KRF, TRF and MRF are laterally-extensive
features, on a regional scale.
2) Breaks exist in these near-surface paleosols which can be attributed to
distributary paleochannels that are active early during aggradational events.
3) Mean widths and geometries (width and orientation) of the identified
paleochannels can be estimated fiom the GPR data.
4) GPR allows for the recognition of facies patterns in the sediments above the
near-surface paleosol (Radar Facies) on the KRF.
We will also comment on and evaluate any morphological differences between
the KRF, TRF, and MRF, which could be attributed to a number of different factors,
including, but not limited to, basinal subsidence, channel morphology and sedimentation,

and Sierran drainage area.

METHODS
To test the first three hypotheses, large-scale GPR surveys combined with
geologic well borings and interpreted county soil surveys were utilized. It was shown by

Burrow et al. ( 1997) that a combination of geophysical techniques, along with standard

hydrologic met
aquifer systems

GPR sur
lateral extent of
Profiles were ru
volume on the u
towed behind a .
1.1.1. Once colle.
II'ell logs. Post p.
contrast betvceer‘
paleosol layer \y,

Itidtlts Oflhe bre-

hydrologic methods, produce a more extensive understanding of sediment architecture in
aquifer systems situated in fluvial settings.

GPR surveys were collected along km scale profiles that attempted to track the
lateral extent of the near-surface paleosol as well as identify breaks in its continuity.
Profiles were run along roads that provided long uninterrupted stretches and low traffic
volume on the upper portions of all three fluvial fan surfaces. The GPR equipment was
towed behind a car, and, in one case, a tractor, to facilitate rapid data acquisition (Figure
1.1). Once collected, the data were processed, plotted and compared with soil surveys and
well logs. Post processing of the GPR data was limited and focused on enhancing the
contrast between areas of shallow and deep signal penetration. Widths of breaks in the
paleosol layer were measured and plotted to gain a better understanding of the mean

widths of the breaks for later use in geostatistical groundwater modeling.

    

GPR Console, Laptop,
and Power Supply in Car

 
 
   
   
   
 

ran-smitting
50 MHz Antenna". ..

  
 

Reclievingi
50 MHz Antenna ,

“ Trigger Wheel

Figure 1.1 Ground penetrating radar system field setup in profiling mode. The system includes a
console, laptop computer, 12-V battery power source (all located in car), and interchangeable 50
and 100 MHz antennae (50 MHz attached in photo). The GPR antennae were powered using two
rechargeable 6-V batteries (chargers in trunk of car). Operational life of the batteries at full
charge, while doing long profiles (km length) averaged approximately 45 minutes.

C ounty
paleochannels I
locations could

increased deptl

County soil surveys were used to highlight the location of “outcropping”
paleochannels on the KRF, TRF, and MRF. Using the C—horizon textures, paleochannel
locations could be identified (Weissmann et al., 2002a) and compared with areas of

increased depth of penetration observed in the GPR profiles (Figure 1.2).

 

 

 

 

Kilometers

TEXTURES

@Gravel .Undifi‘erentiated
iii". Sand [:10verbank Palepcltanpels

  

Figure 1.2 C-horizon texture map of the upper KRF. Dotted lines indicate interpreted
paleochannel locations. (Map modified from Huntington, 1971).

Geologic
by Gary \I'eissm;
Il'CDaI'is) at nur
lithologic well 10.
IhIpothesis four)
paleosols in that s

C omparin.
presides the Oppo
tluI'ial Fans. We h

and location on th

The KRF. '
“braided riI‘er fan"
the Sierra Nevada 1
the San Joaquin V2
Valley east and SOL
It»): on the KRF a
southwest on the K

er '
In TRF areas are .

I ..

'19.»
"T0931 C0mm uni
C.

 

 

Geologic well log analysis consisted of lithologic cores collected and described
by Gary Weissmann (MSU), Thomas Harter, Sevim Onsoy, and Katrin Heeren
(UCDavis) at numerous sites on the KRF (Harter et al., 1999; Weissmann, 1999). These
lithologic well logs provided the groundtruth necessary to verify the radar facies patterns
(hypothesis four) as well as the presence or absence and average depth of the near-surface
paleosols in that specific location.

Comparing the large-scale GPR data collected on the KRF, TRF, and MRF
provides the opportunity to examine any morphologic differences between the three
fluvial fans. We hope to show that the number of identified breaks, their mean widths,

and location on the fan can be identified using GPR.

STUDY AREA

The KRF, TRF, and MRF are stream-dominated fluvial fans (“losimean fan” to
“braided river fan” after Stanistreet and McCarthy, 1993) located where their rivers leave
the Sierra Nevada into the San Joaquin Valley, California (Figure 1.3). The KRF enters
the San Joaquin Valley southeast of Fresno, while the TRF and MRF enter the Central
Valley east and southeast of Modesto. The fluvial fans are of low gradient (approximately
0.002 on the KRF and 0.003 on the TRF and MRF), with the drainages trending west to
southwest on the KRF and MRF, while drainage on the TRF trends more west. The KRF
and TRF areas are also the sites of ongoing hydrostratigraphic characterization studies
(Burow et al., 1999; Weissmann et al., 1999, 2002b; Weissmann and Fogg, 1999; Burow,

personal communication).

 

Digital Elevation Model:
Kings River Alluvial Fan

Figure 1.3 Locations of KRF, TRF and MRF within the San Joaquin Valley of California. (Note
abandoned paleochannels visible on KRF digital elevation model) Background map are USGS
30m Digital Elevation Models.

Repeated glaciation and deglaciation of the Sierra Nevada during the Pleistocene
has created recognizable cycles (sequences) of sediment deposition (J anda, 1966;
Marchand, 1977; Huntington, 1980; Marcth and Allwardt, 1981; Lettis, 1982, 1988;
Harden, 1987; Weissmann et al. 2002a) with San Joaquin basin subsidence acting to
preserve those fan deposits (Lettis, 1982; Lettis and Unruh, 1991; Weissmann et al.,

2002a). Variable subsidence rates for the northern and southern San Joaquin Valley, as

rfported 13)” Lett:

I
TRF and MR1: 1»

 

KRF ( 0.2 mika :1
been recognized

(Huntington. 197
sequences dcscril
Marchand. 1977;
Weissmann. persI
eastern San .10an
based on fossil ex
dating (.4rkley. I

lettis. 1982. 1981

Weissmar
the "
KRF. In this I

[herniated Pleis

“FTPanch. Sip-an HT

W1 .
nere the sequen

mated strata boLI'

:0 C . _
mOlimllles" (\1

{MRF and .\

i111-

reported by Lettis and Unruh (1991), may affect the morphology of the fluvial fans. The
TRF and MRF lay further north and have experienced a slower subsidence rate than the
KRF (0.2 m/ka and 0.4 m/ka respectively) (Lettis and Unruh, 1991). Sequences have
been recognized on the KRF through subsurface analysis as well as soil mapping
(Huntington, 1971,1980; Weissmann, 1999; Weissmann et al. 2002a), with similar
sequences described on other eastern San Joaquin Valley fluvial fans (J anda, 1966;
Marchand, 1977; Marchand and Allwardt, 1981; Harden, 1987; Lettis, 1982, 1988;
Weissmann, personal communication). These sequences have been correlated along the
eastern San Joaquin Valley, with correlations to glacial events and approximate ages
based on fossil evidence, soil morphology, paleomagnetic reversals, and limited ash
dating (Arkley, 1962; Huntington, 1980; Marchand and Allwardt, 1981; Harden, 1987;

Lettis, 1982, 1988).

SEQUENCE STRATIGRAPHY

Weissmann et al. (2002a) proposed a sequence stratigraphic conceptual model for
the KRF. In this work, they related the episodes of aggradation and erosion on the KRF to
the repeated Pleistocene glaciations of the Sierra Nevada (Figure 1.4). Using this
approach, stratigraphic successions are framed within chronostratigraphic sequences,
where the sequence is defined as “. . .a relatively conformable succession of genetically
related strata bounded at its top and its base by unconformities, or their correlative
conformities” (Mitchum, 1977, p.210). Similar sequences have recently been recognized

on the TRF and MRF (Weissmann, personal communication).

PE;

 

1'3

lncis
Valieg

Cl
RB;

 

 

Figure 1.4 Sequen
AI Lou amumula
' “tease In accux.

In each
sediment Seque-
Billing intergla
during the S‘dn
TE‘cOnged 01‘
and Ml‘VardL
Laguni Turl

Alhhardt‘ l 9

A) INTERGLACIAL B) GLACIAL
PERIOD Apex PERIOD

  
    

    

 

fl 44% R eat .
Prograding Active Incised

C) GLACI AL Depositional Lobe D) END OF Valley F."
RECESSI0N GLACIAL PERIOD

   

Intersection

Point .
W Active

Depositional
Lobe

Figure 1.4 Sequence stratigraphic cycles on the KRF as interpreted by Weissmann et al. (2002).
A) Low accumulation space. B) Increase in accumulation space. C) High accumulation space. D)
Decrease in accumulation space. (Modified fiom Weissmann et al. 2002)

In each of the fluvial fans the unconformity that bounds the top and base of the
sediment sequences are represented by a paleosol that developed on the fluvial fans
during interglacial periods (Figure 1.4A), as well as the base of incised valleys formed
during the same period. Five episodes of aggradation and progradation have been
recognized on the Kings River fluvial fan (Marchand, 1977; Huntington, 1980; Marchand
and Allwardt, 1981; Lettis, 1982, 1988). From oldest to youngest these include the
Laguna, Turlock Lake, Riverbank, Modesto, and post-Modesto deposits (Marchand and
Allwardt, 1981; Lettis, 1988) (Figure 1.5). What we see exposed today on the KRF and
TRF represents the post-Modesto interglacial period, therefore, the soils developing today

will later become a sequence boundary once a new glaciation begins. GPR profiles from

this study fOCUSt

Riverbank paleo

Holocer

 

 

Years (Ma)

this study focused one of the near-surface sequence bounding unconformities, the

 

 

 

 

 

 

 

 

 

 

 

 

 

Riverbank paleosol.
Sierra Nevada North American San Joaquin Valley
Glacial Stages* Composite Events Stratigraphy“
Holocene—woe»:- c . ., . . . .3
Hilgard or Tioga W' . Modesto
2 lsconsm .
Tenaya or Tahoe Formation
0.2 — Tahoe or :gitM'ddle Riverbank
Mono Basin '. ocene Formation
(lllmoran) l
l
75 0.4 - Casa Middle Middle I
.2, Diablo Pleistocene V
m — 7
h .
8
>' 0.6 ‘ .
Donner Lake or Early Middle Upper Turlock
- Red Medow Pleistocene Lake
0.8 ‘
Sherwin or Lower Turlock
El Portal Lake
1.0 ‘
2.0 McGee or Laguna
ZtOS Glacier Point Formation

 

 

 

' Stratigraphic correlations to marineisotope stages
and Sierra Nevada glacial stages from Lettis (1988)

Figure 1.5 Stratigraphic column for the KRF (based on Marchand and Allwardt, 1981; Lettis
1988) showing the five “sequences” described by Weissmann et a1. 2002. (Modified from
Weissmann et al. (2002))

While working within the sequence stratigraphic framework, it is important to
understand the controls on sequence development. In a marine setting, relative sea level
(controlled by eustatic sea level and tectonics) defines the space available for sediment
accumulation, also known as accommodation space. In the fluvial continental setting,

accommodation space should be viewed as a combination of two different concepts,

10

ammzulurlon 5;
system. urcumrl
where this ratio 1
Accumulation 5g

accumulation sp

accumulation space and preservation space (Blum and TOrnqvist, 2000). In a fluvial
system, accumulation space is controlled by the ratio of sediment supply to discharge,
where this ratio controls whether the system is aggrading, degrading, or at grade.
Accumulation space exists while aggradation occurs in the system, while negative

accumulation space exists when degradation is occurring.

Plan View

 

 

Down-channel Cross Section View

 
  

Adjacent Fan
Surface Intersection Point
A ‘ ~ 2 A'
/ 1" s‘-‘~ ' .3
Channel —

 

 

 

 

Profile

 

 

Negative Positive
| Accumulation Space 1 Accumulation Space |

 

Figure 1.6 Accumulation space on fluvial fans relative to the fluvial fan surface and other fan
features. (Modified from Weissmann et al. (2002))

In the fluvial fan setting, the morphologic feature that separates areas of positive

accumulation from areas of negative accumulation is the intersection point (Figure 1.6)

11

lWeissmann et .

 

exists. as 51101411

   
 

the intersection ;
indicating positi
intersection poili
sediment supply
accumulation spa
near the apex of
deposition occur
5123C? (interglaci
uhich the ricer l
[0 Upper fan reg
“hat is Slgnj fic
bases that devel
SE’Iluence bOunC

BlUn] 31‘
L occurring .

and TCmOVal“ _

(Weissmann et al., 2002a). Above the intersection point, negative accumulation space
exists, as shown by the fact that the river is constrained within an incised valley. Below
the intersection point, aggradation occurs in the form of an active depositional lobe, thus
indicating positive accumulation space. Over the life of the eastern valley fluvial fans, the
intersection point has changed position in response to the changing ratio of discharge to
sediment supply of the primary river forming the fluvial fan. During times at which
accumulation space was at its highest (glacial periods), the intersection point was located
near the apex of the fluvial fan (Figure 1.48 & C). During these times, open-fan
deposition occurred over large areas of the fan surface. During times of low accumulation
space (interglacial periods), the intersection point moved toward the toe of the fan, above
which the river became entrenched in an incised valley (Figure 1.4A & D). Thus, the mid
to upper fan regions were exposed to soil development, erosion, and eolian reworking.
What is significant about this time in the fluvial fans history is that the soils and valley
bases that develop during this time will later mark the unconformities that form the
sequence boundaries.

Blum and Tomqvist (2000, p.20) describe the development of preservation space
as occurring “. .. when subsidence lowers these deposits below possible depths of incision
and removal”. Therefore positive accumulation space allows the stratigraphic sequences
in fluvial settings to form, while the development of preservation space allows them to be

preserved in the stratigraphic record.

THESIS OUTLINE

This document is divided into three main sections with subsequent appendices:

12

o The firs".

 

run on it

review o-

chapter .
o The seco

dunngth

 

KAC stut
discussic
groundu
GPang
' Thethu'
the wor'
° Thefol

O

O

O

The first section, covered by Chapter Two, covers the large-scale GPR surveys
run on the KRF, TRF and MRF and presents the results of these surveys. A brief
review of sequence stratigraphy and GPR methodology is also presented. This
chapter also forms the draft of a manuscript that will be submitted for publication.
The second section, covered by Chapter Three, covers other observations made
during the course of this work, including GPR facies pattern recognition at the
KAC study area, groundtruth of the paleosol at the KAC using borehole logs, a
discussion on near-surface paleosol topography and its implications to future
groundwater modeling, as well as a brief discussion of our attempt to automate
GPR profile interpretation using MATLAB scripts.
The third section, covered by Chapter Four, revisits conclusions reached during
the work conducted for this thesis.
The following appendices are attached:
0 Appendix A contains all large-scale raw GPR profiles.
0 Appendix B contains all small-scale raw GPR profiles from the Kearney
Site.
0 Appendix C contains all CMP surveys used to determine near-surface
GPR signal velocities.
0 Appendix D describes GPR data collection methodology as well as a
description of data processing and analysis.
0 Appendix E contains all Matlab scripts developed during work.
0 Appendix F contains metadata and sources for GIS coverages produced to

aid in the visualization of this project.

13

Since its
etl‘ectix'e imagin
ol'near surface s

8; Smith. 1991; f

 

 

 

Oyergaard, 20L):
subsurface that 11

In a prey:
showed that a nu
tracked using Gl
represents a dept
now hypothesiZc
sequence stratig
that influences g
31.. in press) anc

[Ydflspon b) prQ

CHAPTER TWO

INTRODUCTION

Since its introduction, ground-penetrating radar (GPR) has allowed for quick and
effective imaging of the stratigraphy, internal structure, and, in some cases, the lithology
of near surface sands and gravels (e. g., Davis & Annan, 1989; Beres & Haeni, 1991; Jol
& Smith, 1991; Smith & J01, 1992; Huggenberger, 1993; Beres et al. 1995; Jakobsen &
Overgaard, 2002). GPR produces nearly continuous high-resolution profiles of the
subsurface that are similar to those produced using seismic-reflection methods.

In a previous study on the Kings River fluvial fan (KRF), Burrow et al. (1997)
showed that a near-surface laterally continuous fine-grained layer could be successfully
tracked using GPR. This fine-grained layer was later identified as a paleosol that
represents a depositional hiatus on the KRF (Weissmann, et al. 2002a). That paleosol is
now hypothesized to be a sequence stratigraphic boundary (Weissmann 2002a). This
sequence stratigraphic boundary is hydrologically significant because 1) it is an aquitard
that influences groundwater flow and solute transport (Weissmann, 1999; Weissmann et
al., in press) and 2) breaks in the sequence boundary influence groundwater flow and
transport by providing permeable pathways into deep portions of the aquifer. Therefore,
determination of break geometry and the causes of these breaks are significant for
groundwater flow and contaminant transport modeling.

We intend to show through the use of GPR the following:

14

1) Thu‘
and
regitl

3.) Brett}.
distr‘
fluH
be es

maps

 

ln additic
tlut'ial fans (TRl
morphological d
but not limited ti

oidata collectio

The KR
“braided fiver f

163‘"? the Sierra

Enters the San '-

ll’ii: KRF and (J

‘37]

[he KR 1: 31‘

3.1] area 0f 3p}

‘

1) That near-surface paleosols on the KRF, Tuolumne River fluvial fan (TRF)
and Merced River fluvial fan (MRF) are laterally continuous features, on a
regional scale.

2) Breaks exist in these near-surface paleosols, which can be attributed to
distributary paleochannels that once carried outwash sediments over the
fluvial fans surfaces; and the mean widths and geometries of these breaks can
be estimated by combined analysis of GPR profiles and county soil survey
maps.

In addition to the above hypotheses we also intend to discuss how the northern
fluvial fans (TRF & MRF) and southern fluvial fans (KRF in particular) exhibit notable
morphological differences that could be linked to a number of different factors, including
but not limited to, regional basin subsidence differences, upland drainage area, location

of data collection, and the amount of data collected on both fluvial fans.

STUDY AREA

The KRF, TRF, and MRF are stream-dominated fluvial fans (“losimean fan” to
“braided river fan” after Stanistreet & McCarthy, 1993) that are located where their rivers
leave the Sierra Nevada into the San Joaquin Valley, California (Figure 2.1). The KRF
enters the San Joaquin Valley southeast of Fresno while the TRF and MRF enter the
valley east of Modesto. All three fluvial fans are of low gradient (approximately 0.002 on
the KRF and 0.003 on the TRF and MRF), with the drainage trending west to southwest
on the KRF and MRF, and west on the TRF. The drainage basin above the KRF covers

an area of approximately 4,334 km2 (corrected drainage area from misprint in Weissmann

15

et al. 3002). Al“

 

m3. while abo‘
(Drainage basit‘
area of approxit

COVCI’S an area 0

 

hydrostratigrapl‘
1997; \l'eissmat

Weissmann, per:

 

 

et al. 2002). Above the TRF the drainage basin covers an area of approximately 3,940
kmz, while above the MRF the drainage basin covers an area of approximately 2,685 km2
(Drainage basin areas reported from USGS stream gauging stations). The KRF cover an
area of approximately 3,150 kmz, the TRF covers and area of 576 kmz, while the MRF
covers an area of 552 kmz. The KRF and TRF are both the sites of ongoing
hydrostratigraphic characterization and groundwater modeling studies (Burow et al.,
1997; Weissmann & Fogg, 1999; Weissmann et al., 1999, 2002b, in press; Burow &

Weissmann, personal communication).

    

\s

[.1 Merced River
CALIFORNIA /

Digital Elevation Model:
Kings River Alluvial Fan

Figure 2.1 Study area location map, highlighting the locations of the Kings River fluvial fan,
Tuolumne River fluvial fan, and the Merced River fluvial fan. Images of fans are 30m digital
elevation models from the USGS. Note highly visible abandoned channels on KRF, and lack
thereof on the TRF and MRF.

SEC

Repeatt‘

created recogni
I977; Huntingtt
Weissmann. 19*
preserve those tl
3003a). Sequent

as soil mapping

 

uith similar 5qu
{Helleyz 1966; J '
1987; Lettis 198
Weissma
the KRF. In this
the repeated Plei
approach, stratigr
Where the sequent
related strata bour
cOttforrm'ties” (Mi
in the TRF (Weiss
SEQUence <

.i‘clicity in the Sie

SEQUENCE STRATIGRAPHY OF FLUVIAL FAN DEPOSITS

Repeated glaciation and deglaciation of the Sierra Nevada during the Pleistocene
created recognizable cycles (sequences) of sediment deposition (J anda, 1966; Marchand,
1977; Huntington, 1980; Marchand & Allwardt, 1981; Lettis 1982, 1988; Harden, 1987;
Weissmann, 1999, Weissmann, et al. 2002a) with San Joaquin basin subsidence acting to
preserve those fan deposits (Lettis, 1982; Lettis & Unruh, 1991; Weissmann et al.,
2002a). Sequences have been recognized on the KRF through subsurface analysis as well
as soil mapping (Huntington, 1971, 1980; Weissmann, 1999; Weissmann et al. 2002a),
with similar sequences described on other eastern San Joaquin Valley fluvial fans
(Helley, 1966; Janda, 1966; Marchand, 1977; Marchand and Allwardt, 1981; Harden,
1987; Lettis 1982, 1988).

Weissmann et al. (2002a) proposed a sequence stratigraphic conceptual model for
the KRF. In this work, they related the episodes of aggradation and erosion on the KRF to
the repeated Pleistocene glaciations of the Sierra Nevada (Figure 2.2). Using this
approach, stratigraphic successions are framed within chronostratigraphic sequences,
where the sequence is defined as “. . .a relatively conformable succession of genetically
related strata bounded at its top and its base by unconformities, or their correlative
conformities” (Mitchum, 1977, p.210). Similar sequences have recently been recognized
in the TRF (Weissmann, personal communication).

Sequence development on these fluvial fans occurred in response to glacial
cyclicity in the Sierra Nevada. At the end of glacial periods and the beginning of
interglacial periods, fan incision as well as a basinward shift in the fan intersection point

occurred due to declining sediment supply and stream discharge (Figure 2.2A & D).

17

Inc
Va

Figure 2.2 Sequcn
20023. (Modified

Stream in
lluxial fan. Will cl
fan. During this ti
$011 det'CIOpnient
tn the production
lhesoils and the b

Madam],

Asgradam

Sunni

 

y and stream
. li‘ .‘
alas mg for the a"

ll' 1' .
e‘s‘ma’m et al. a

1' 1l , -

 

A) INTERGLACIAL B) GLACIAL
PERIOD Apex PERIOD Apex

   

 

 

A? Prograding Active

C) GL ACI AL Depositional Lobe D) END OF Valley F."
RECESSION GLACIAL PERIOD
m m m m

 

 

  

Intersection
Point

Figure 2.2 Sequence stratigraphic depositional cycle on the KRF as proposed by Weissmann et al.
2002a. (Modified from Weissmann et al., 2002a)

Active
Depositional
Lobe

Stream incision created an incised valley in the middle and upper portion of the
fluvial fan, which, therefore, confined deposition to more distal portions of the fluvial
fan. During this time the middle and upper—portions of the fluvial fan were exposed to
soil development and erosion, and/or eolian reworking. This time period then culminated
in the production of an unconforrnity on the middle and upper-fan surfaces, marked by
the soils and the bases of the incised valleys that represent the fluvial fan sequence
boundary.

Aggradational events occur during glacial periods in response to higher sediment
supply and stream discharge, with sediment supply out weighing stream discharge, thus
allowing for the aggradation (Marchand and Allwardt, 1981; Lettis, 1982, 1988;
Weissmann et al. 2002a). Increased aggradation during glacial periods filled the incised

valley with a fining-upward succession of relatively coarse-grained channel and overbank

deposits. and. t

 

come-grained.
deposits. The CI:
decreases in set
basinu‘ard shi it

In the ca

 

base of the sedit
fluvial fans duri:
valleys “hose c'
dei'elopment. Fl
recognized on t‘
1981; Lettis. 19
lake, Riverban
Lettis. 1988) (E
TRF. and MR}
Silrface areas c
dcPosits. Henc
new glaciatior
L‘ac

king One c

smalliles [he

deposits, and, once filled, the aggradation event led to relatively unconfined deposition
over the fluvial fan surface (Figure 2.23 & C). Open fan deposits are a mix of discrete
coarse-grained, channel-fill deposits within fine-grained, silt-dominated overbank
deposits. The end of glaciation then led to a repetition of the stratigraphic cycle, with
decreases in sediment supply and stream discharge that resulted in fan incision,
basinward shift in deposition, and soil development on the exposed upper fan surface.

In the case of the KRF, TRF and MRF, the unconformity that bounds the top and
base of the sediment sequences are represented by a paleosol that developed on the
fluvial fans during waning glacial and interglacial periods, as well as the base of incised
valleys whose channels flowed over the fluvial fan surface during the time of soil
development. Five distinct episodes of aggradation and progradation have been
recognized on the KRF (Marchand, 1977; Huntington, 1980; Marchand & Allwardt,
1981; Lettis, 1982, 1988). From oldest to youngest these include the Laguna, Turlock
Lake, Riverbank, Modesto, and post-Modesto deposits (Marchand & Allwardt, 1981;
Lettis, 1988) (Figure 2.3). Most of the land surface we see exposed today on the KRF,
TRF, and MRF represents the post-Modesto interglacial period, with some upper fan
surface areas containing outcrops of both Riverbank and Turlock Lake interglacial period
deposits. Hence the soils developing today will later become a sequence boundary once a
new glaciation begins. GPR allowed us to further analyze these sediment sequences by
tracking one of its near-surface bounding unconformities, the Riverbank paleosol, which

separates the Riverbank deposits from the more recent Modesto deposits (Figure 2.4).

19

HoIC

Yon MM "l

Figure 2.3 Stratigr

Marchand & All w;

W

 

 

 

 

Sierra Nevada

North American

San Joaquin Valley

 

 

 

 

 

 

 

 

 

 

 

Glacial Stages* Composite Events Stratigraphy"
Holoce. .e
_ HIlgard or TIoga Wisconsin Modesto
Tenaya or Tahoe Formatlon
02 — Tahoe or :tiesthllrdile Riverbank
Mono Basin 6. 0.“? e Formation
(IIIInoIan) l
|
A I
(U 0.4 ‘ Casa Middle Middle I
g Diablo Pleistocene V
2 ‘ ?
8
>' 0.6 ‘ .
Donner Lake or Early MIddIe UpperTurlock
_ Red Medow Pleistocene Lake
0.8 ‘
Sherwin or LowerTurlock
El Portal Lake
1.0 ‘
2.0 McGee or Laguna
2t°5 Glacier Point Formation

 

 

' Stratigraphic correlations to marine isotope stages
and Sierra Nevada glacial stages from Lettis (1988)

Figure 2.3 Stratigraphic column for the eastern San Joaquin Valley Quaternary deposits based on

Marchand & Allwardt, (1981) and Lettis, (1988). (Modified from Weissmann et al., 2002a)

 

 

'

 

 

 

 

 

 

Kilometers

Elevation (m)

Figure 2.4 Cross-section through the upper KRF. Cross-section is parallel to depositional dip and

shows the proposed laterally continuous sequence bounding paleosols. (Modified from

Weissmann et al. 2002a)

20

GPR S}
he 80-1000 .\1 l

subsurface ( Re}

 

IE
Grour
surfa
V‘
E
Q
o
Q
(C
q) l
.E /
I. Army,
leeI‘W
iiC‘rffld
Pilin- -
ifwez'i A) 31
rcu’ijDaWSa: Ami)
Firm-em .‘ nna
UPR [I 0‘65 0f
a\l:‘,- aCFS' 12h] r
usurracer‘ k"

 

 

GPR THEORY
GPR systems use short pulses of high frequency electromagnetic (EM) energy (in
the 80-1000 MHz range) to detect inhomogeneities in electrical properties of the
subsurface (Reynolds, 1997) (Figure 2.5).
(A)
I
W

F—i v Ream.

/
/
/

 

 

 

 

l
!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(B) /
Ground .’ Direction OfSurvey—»
surface i ,
5 . .
H
D.
a:
O
1 Reflector
/
(C)
k k S K K
m —:> —- 2:— 4» —:> — .»— a» —-.i‘—‘1E:
E Arrival of
[-3 Arrival of AirWave
Direct Wave
1 (Ground Wave)
W 1Arrival of
Reflected
Wave

Figure 2.5 A) Simplified schematic diagram of the ground penetrating radar system. (Modified
from Davis & Arman (1989)) B) Schematic procedure for GPR survey profiling, which involves
repetitive moves of both the transmitter and receiver held at a constant spacing. C) Schematic
GPR traces, highlighting the arrival of the air and ground wave pulses and a reflected wave from
a subsurface reflector. ((B) & (C) Modified from Jol & Smith 1991)

21

\then energy r
properties ol‘tl:
the surface \Vlll
Water content.
the electrical pr
Haeni et al.. 19.4

recorded. procc~

 

through the subs
nay traveltim'e.
depth section on
calculated. Velot
ICMPI sun'eys I.
show the hyperbt
IFigure 2.6). This
scale for the radar
GPR enerp
Attenuation in gCt
35 dii’quartz sand

.9 .
t-lldULlOrS SuCh
a.

 

 

When energy radiated from the GPR antennae encounter changes in the bulk electrical
properties of the materials it is penetrating, some of the energy is reflected back toward
the surface while the rest is transmitted deeper into the subsurface (Reynolds, 1997).
Water content, dissolved minerals, expansive clays and heavy mineral content all affect
the electrical properties of geologic materials (Wright et al., 1984; Olhoefi, 1984, 1986;
Haeni et al., 1987; Reynolds, 1997). The signal that returns to the surface is then
recorded, processed, and displayed. A plot of the total traveltime for the signal to pass
through the subsurface and return from a reflector is produced and represents the two-
way traveltime, which is measured in nanoseconds. This plot can then be converted to a
depth section once the radar wave velocities in the different subsurface layers have been
calculated. Velocities in the near surface may be determined by common mid-point
(CMP) surveys (Jol & Smith, 1991; Jakobsen & Overgaard, 2002). CMP experiments
show the hyperbolic relationship between reflection arrival time and antenna separation
(Figure 2.6). This allows for the establishment of wave velocity and, therefore, a depth
scale for the radar profile. An example velocity calculation is shown in Figure 6.

GPR energy attenuation or absorption limits depth of penetration of EM waves.
Attenuation in geologic materials is limited when probing poor electrical conductors such
as dry quartz sand, but is much higher when attempting to penetrate good electrical
conductors such as clay rich materials (Wright et al., 1984; Olhoeft, 1984, 1986). Table
2.1 lists values of conductivity and relative dielectric permittivity for selected materials.
A more complete discussion of radar wave attenuation and propagation properties as well
as effective radar range analysis is presented in Annan and Davis (1977) and Sheriff

(1984).

22

f,
i hIalt
&L_————-
We.
ML-
Sandld

WI
we |

Ch’hamRflec»

We

met
Gammld

Gammtweo
\
'hMeZl.Appro\
materials. (Data ti

 

 

 

fiflm26

nP.' A ‘

qkflw JCOm

Emilie 01 magn‘
‘ a CMP

Material Conductivity (mhos per Relative dielectric

T 1
materials. (Data from Ulriksen, 1982). Modified from Beres & Haeni (1991).

 

 

 

 

(A)
Transmitter Positions Reciever Positions
/1 r\
Steps

4918I7l615141321111213141516171811

(B)
50 .,
100 "“

I Air Wave

   

. ~ - r 1. V V” ‘7 .1 \
4 8 12 16 20 24 28 GrBund Wave
VELOCITY Antennae Seperation (m)
= i / slope (of groundwave)
= dx (surface distance) / dy (two-way traveltime)
= 30m/234ns = 0.13 m/ns = Near-Surface Velocity

Figure 2.6 A) Common Mid Point (CMP) experiment used to calculate the propagation velocity
of the electromagnetic GPR waves in the near-surface sediments (Modesto Formation). B) An
example of a CMP used to determine the near-surface sediment velocity on the KRF.

23

\t'e USC
reflection sun "
stud) areas Int
nere utilized-

aim at app“)X

 

a"? ""

l‘l§1‘~i€2.7 Groun "
console. laptop cc:
arc l00 MHz ant '
rechargeable 6 \'Ll
cw ' i I
ge uhile dom‘

Each step locatio

GPR METHODOLOGY
We used the Sensors and Sofiware Inc. pulseEKKO 100TM radar system in
reflection survey mode with a 400V transmitter (pulser voltage) to collect data from the
study areas. Interchangeable sets of antennae having 50 and 100 MHz center frequencies
were utilized. The system was towed behind a car on a fiberglass GPR cart at a distance

of 1m at approximately 5 km/hr (or approximately 3 mi/hr) (Figure 2.7).

    

GPR Console, Laptop,
and Power Supply in Car

     
   

TriggerWheel

Figure 2.7 Ground penetrating radar system field setup in profiling mode. The system includes a
console, laptop computer, 12-V battery power source (all located in car), and interchangeable 50
and 100 MHz antennae (50 MHz attached in photo). The GPR antennae were powered using two
rechargeable 6-V batteries (chargers in trunk of car). Operational life of the batteries at firll
charge while doing long profiles (km length) averaged approximately 45 minutes.

Each step location (vertical trace) in reflection mode was stacked at least 8 times with a
time window of 800 ps (1600 in some cases). GPR data were collected every 0.5 m,
triggered by an odometer wheel, with the antenna separation maintained at 2 m (Figure
2.7). Profiles were processed and plotted with WINEKKO (version 1.0) and

EKKOMAPPER (version 2). Processing was intentionally limited since interpretation of

24

the data diC
decaying l0
reflections.
ln or
velocity oft.
conducted at
GPR
total. approx.
approximutcl
collected on t

collected on t.

(A)

a

l
i l
i
r
,.
l.

 

Cr . .. ,".|'.'. D
. .) 4
U1

the data did not require it. A dewow time filter was applied, which removes any slowly
decaying low frequency “wow” which may be superimposed on high frequency
reflections.

In order to develop depth scales for the GPR profiles, an averaged near-surface
velocity of 0. 14 m/ns was determined from fifteen common mid-point (CMP) surveys
conducted at several sites on the both the KRF and the TRF (Figure 2.6).

GPR surveys were run along grids of roads on the fluvial fan surfaces and, in
total, approximately 120 km of data were obtained on the KRF while a combined total of
approximately 70 km of data were collected on the TRF and MRF (Figure 2.8). Data
collected on the TRF focused on deposits south of the Tuolumne River, while data

collected on the MRF focused on deposits north of the Merced River.

(3)

   

 

-' , 0 4 8 16 24 :3
O 2.5 5 10 15 20 Kilometers

Kilometers

Figure 2.8 GPR profile location maps for (A) the KRF and (B) the TRF and MRF. Profiles
clustered in the southeastern portion of (B) are located on Merced River deposits (See Figure 1).
Background maps are 30m USGS seamless digital elevation models.

25

cPR t‘

1) Llilt

 

 

pale
3) Line

3) Line

 

The near
knoun to have c
Harden, 1987; H
they are basicall
paleosols clay~ri
three fluvial fans

he key indicator

GPR profile selection criteria consisted of locating lines that meet the following
conditions:
1) Lines were located on the upper fluvial fan surface underlain by Riverbank
paleosols, or were hypothesized to be underlain by Riverka paleosols.
2) Lines were along roads that provide both long distance and straight paths.
3) Lines were along roads with low traffic volume and had limited potential for
the contribution of significant sources of GPR signal interference (e. g.

abundant overhead high-power lines as well as urban areas).

GPR RESULTS

The near-surface (Riverbank) paleosols observed on the KRF, TRF, and MRF are
known to have clay rich B-horizons and exhibit hardpan development (Huntington, 1980;
Harden, 1987; Harter et al., 1999; Weissmann, 1999; Weissmann et al. 2002a), therefore
they are basically impenetrable by the GPR signal. Since the signal is attenuated in the
paleosols clay-rich matrix, our large-scale survey was able to effectively track them on all
three fluvial fans (Figure 2.9A). Shallow GPR signal attenuation within the paleosol was
the key indicator of its presence.

Although laterally continuous, paleosols on the KRF appear to have been
dissected by paleochannels shown on the GPR profiles by zones of relatively deep
penetration. Areas along our profiles that showed notable increases in the signal
penetration depth were interpreted as areas where the paleosol was missing (break in
continuity) (Figure 2.9B). Channel incisions that removed the paleosol on the KRF varied

in character from deep relatively narrow incisions (down to 10 m) to shallow wide lateral

26

l.)l"')th I!) Moat‘wfg

{Jo-p”) In leur a.

running {we —r—

O

scouring which simply removed the paleosol and rarely incised deeper then 6 m (Figure

2.93). The Modesto incised valley fill, described by Weissmann et al. 2002a, has a

similar character to breaks observed using GPR, but the incisised valley fill is much

wider. Between channel incisions, the paleosol was observed to be laterally continuous.

Depth in Meters

Depth in Meters

Smith Road Segment 1 (KRF)

 

A)

North Transition South
Paleosol Near Surface l Paleosol Beneath Modesto Deposits

I i : l

Jm'r—r'wmwtrm“ “mw'rrww wv , .. " ~ o r ¢--- V'H-‘f . ,. w wrr. .r: em."- “-2-" ~33

 

Mu)!" nan-Hg; «I.» run-1 u- 'r- '.:-‘1' uu‘u-dh unlim3bkffuunundp¥ n48 bh'mfi a“: Miii.‘~-h-5u—dd guh'b‘matsiahiléi. Bud“ i-uf;t 4‘- "Rum

    
  

        
     

    

'f'“' ~ IHW

~WI~ “i.“ m ‘w.w {w If ;‘.'r&.;
‘mau .l‘i’rp- ".‘I-J.‘ ”Tr M.:‘*;'.m.:u’ u ’1»sz .‘ WW:

 

 

w" v 9“. o- 1', W8; Ti... a a ll (“ii - -.
MalaimfiutA‘rruflrms -Aru-h'n ‘ J Adi UL" ”It'd-LI.» .3». mem
3.. I . , -atvz... ~24 _. Amm¢uflx an”. -~W -~\.--uI-I-'M “WWW”
Machev—o- ‘ayo—oov-v'. "i‘ h-A— re-W .‘.—-. .5 -.- «r -o——\~~..o -~- Mm —— -.. —o- vavm ut- r fiv-~‘-O-'
~1\I.¢w‘.’°':') “Inuit". .i... .I. -. s... A. 3‘.» “a” . :.' 7‘. “‘7". ".‘.,“"'.""\..K.~I‘:." ".\' .f'fipfl

 

 

—‘.vm r‘.:.::..‘-:~v—:r‘, . ,___v . ~., v w w. fi— -
‘—»--\-~-~.-.—‘-—.v_u -4......‘... —a~_--- -..~-~..-.--—.. .- -u---......- .- . . ,__.-.. ._-..-a.‘ k.u.._.u_-.AI—.-.~..- -.:...' .....4 4.3

0 too 200 300 400 500 600 700 800 900 mm 1100 1200 13m 1400
Position in Meters

Del Rey Road Segment 18 (KRF)

 

 

3)
North Shallow Paleosol Absent South
I I
Shallow Deep Channel Shallow Channel
, Paleosol Incision I Incision
r I l I
m... "tum“..a 2.222 W" "tare"... 23"....-";.."". .'.<..:::._..-'- .. 3:23: 35:; 23:2: 33:3:

 

 

 

 

o 100 200 300 400 500 600 700 800 900
Position in Meters

Figure 2.9 A) GPR profile on the KRF showing the typical paleosol reflection pattern when
exposed at the surface as well as buried below Modesto deposits. Beyond 750 m paleosol is
below Modesto deposits and is expressed as the tight dark band couplet at approximately 5 m
depth. B) GPR profile on the KRF showing the typical reflection pattern observed when entering
a deep paleochannel incision as well as an area that shows shallow channel incision. Shallow
incision may be the result of lateral channel migration across the fan surface through time.
Stacked hyperbola observed on both GPR profiles represent overhead power lines, while the deep
narrow bands as observed at approximately 290 m on profile A and 380 m on profile B represent
irrigation ditches.

27

Fresn:
\
\
\\
/\
Hwy
99

FIG

 

first “i 2 "

Fresno
\\\ ‘ am!
>\\\ -- as?
Hwy 3;" ' '
99

 

 

 

 

 

 

0
TEXTURES Kllometers GPR PROFILES
. . Paleosol, ,
.Undifferentlated Dee Inc1310n
.Overbank Sha ow Incision
Corrupt Profile
Questionable

Figure 2.10A Map showing a portion of the upper KRF surface. C-horizon textures clearly show
the location of paleochannels (stippled pattern), overbank deposits (light gray) and hardpan (dark
gray) on the KRF. GPR profiles have been interpreted to highlight areas of deep channel incision
(yellow), shallow charmel incision (green), and paleosol (red). Questionable areas highlighted in
blue and corrupt lines highlighted as black (Soil map modified from Huntington, 1971) *This
figure is presented in color.

28

Modestr
L—u

 

Modesto’

fi‘fifis swig??? “fig '22";
. '2 is as

'.‘r ‘
3 I
, -J-
.
2

*2! .
" "if :3“th
4': W

 

 

 

 

 

 
 

0 3- 6 12 18 24
TEXTURES Kllometers GPR PROFILES

- - Paleosol
Urban agnceli’gffintlated Dee Incision

 

Sha ow Incision
Questlonable

 

Figure 2.103 Map showing a portion of the upper TRF and MRF surfaces. C-Horizon textures
indicate location of sands (stippled pattern), overbank deposits (light gray) and hardpan (dark
gray) on the TRF and MRF. GPR profiles have been interpreted to highlight areas of deep
channel incision (yellow), shallow channel incision (green), and paleosol (red). Questionable

areas highlighted as light blue. (Soil map modified from Huntington, 1971) ’This figure is
presented in color.

29

On the

teature. yet 11 2

 

 

3.108,). On th
sandy deposits
In man

paleochannel l

 

 

plotting the C -
paleochannels
Mapped soil 5.
gravel. sand. c
[ht GPR data.
soil SUTVCy SU
Sections of th
that did not C
mAmber of til
the SOIl SLIrV.
(upping). or
The 2
Once break
compared “
KR Obs en'.
u'idihs ther
Cit

annel b9

On the TRF, the Riverbank paleosol was again identified as a laterally continuous
feature, yet it lacks the abundant paleochannel incision observed on the KRF (Figure
2.10B). On the MRF, the Riverbank paleosol is obscured due to eolian reworking of
sandy deposits, which has created dunes in that area (Figure 2.10B).

In many instances breaks identified in the GPR profiles were directly correlated to
paleochannel locations observed on county soil surveys. Previous work has shown that
plotting the C—horizon textures of the different soil series allowed for the identification of
paleochannels on the KRF (Weissmann, 1999; Weissmann et al. 2002a) (Figure 2.10A).
Mapped soil series were placed into four separate categories based on C-horizon textures,
gravel, sand, overbank, and near-surface hardpan. The resulting maps were compared to
the GPR data. Coincident breaks in the GPR profiles with paleochannel locations on the
soil survey support the hypothesis that paleochannels were responsible for removing
sections of the laterally continuous Riverbank paleosol. Areas indicating paleosol breaks
that did not correspond well with indications of channels on the soil survey could have a
number of different explanations, including (1) a paleochannel that does not “outcrop” on
the soil surveys (not shallow enough to be identified), (2) removal for agriculture
(ripping), or (3) removal during road construction (if shallow enough).

The widths of paleochannels were approximated directly from the GPR profiles.
Once break locations were identified and plotted, their widths were measured and
compared with paleochannel locations observed on the soil surveys. A good correlation
was observed, with paleochannels on the soil surveys tending to show slightly larger
widths then the GPR profiles. GPR was therefore more effective at delineating the

channel boundaries. Widths of the channels observed on the GPR profiles are apparent

30

n‘idthS Since ti

correct for (hi:

 

surveys and 1h
calculate a“ 65
KRF was appl—
value was calt‘
breaks were 0}.

presence of du

 

OBS

Althou:

KRF there are
include overall
and the numbe-
Draina
having the she
relationship hr
the result ofir

though the dr:

widths since the GPR profiles tended to cross the paleochannels at an oblique angle. To
correct for this, the orientation of the paleochannels was noted from the county soil
surveys and the angle at which the GPR profile crossed the paleochannel was used to
calculate an estimated width of the channel. The mean width of breaks identified on the
KRF was approximately 320 m with a standard deviation of approximately 260 m. This
value was calculated based on a total of 16 discrete breaks observed on the KRF. No
breaks were observed on the TRF and breaks (if any) on the MRF are obscured by the

presence of dunes in the study area.

OBSERVED DIFFERENCES BETWEEN THE KRF AND TRF

Although similar sequences have been observed and described on TRF, MRF and
KRF, there are notable differences between the two fluvial fans. These differences
include overall fan size, the apparent amount of Modesto deposits preserved on each fan,
and the number of observed breaks in the underlying Riverbank paleosol.

Drainage basin areas above the TRF and KRF differ by 394 kmz, with the KRF
having the slightly larger drainage basin area. Harvey (1989) has shown that there is a
relationship between drainage basin area and fluvial fan area with the increase in fan area
the result of increasing magnitude of sediment load with increasing drainage area. Even
though the drainage areas are not significantly different, the TRF is much smaller then
the KRF in terms of fan area. Therefore, drainage basin area does not appear to influence
fan size in the San Joaquin Basin fans. We believe this indicates that stream base level

and basin subsidence are potentially important controls on fan size.

31

Variab
have influence
calculated the 7
regionally exit
subsiding fast.
TRF, which iiL
KRF. Di fferingl
in the fan moi-p

less accommod

 

 

 

 

 

fluvial fan,
Another
me timing 01‘ tl‘

“Ems durin

H
\—

rrr‘.

{Weissmann et
Joaquin delta [1-
may ha‘ie allox
1° bipass the f
there is legs V0
Modesio age C

‘Anolhc

theme fluW-a]

number of GP]

l‘-e

Variable subsidence rates for the northern and southern San Joaquin Valley may
have influenced the morphology and sizes of the fluvial fans. Lettis & Unruh (1991)
calculated the subsidence rate of the San Joaquin Basin using the Corcoran clay, a
regionally extensive 600 ka lacustrine unit, and have shown that the southern valley is
subsiding faster then the northern valley (0.4 m/ka and 0.2 m/ka respectively). Thus, the
TRF, which lies further north, has been subjected to a slower subsidence rate then the
KRF. Differing subsidence rates may therefore be one of the factors causing a difference
in the fan morphologies, with the lower subsidence rate in the northern valley providing
less accommodation space for sediments on the TRF, thus forcing sediment to bypass the
fluvial fan.

Another possible reason for the morphology and size differences could be due to
the timing of the fan aggradation with sea-level position. Timing of large sedimentation
events during glacial events on the KRF coincides with low eustatic sea levels
(Weissmann et al., 2002a). However, because the Tuolumne River is located near the San
Joaquin delta the Tuolumne River may have been adjusted to the lower sea level. This
may have allowed for the river to be held lower in its incised valley and for the sediment
to bypass the fan system for a longer period of time. Evidence for this is exhibited in (1)
there is less volume of Modesto sediments on the TRF and (2) there are no apparent
Modesto age channels outside of the current channel location (Figure 2.10B).

Another factor that may have influenced the number of observed breaks between
the two fluvial fans is the difference in the amount of data collected on each. The lower
number of GPR profiles on the TRF could have resulted in a bias, where fewer breaks

were observed.

32

Lastly
the identificat

developed by

Grount
ofnwsurfaa
identify erosio
paleochannels
paleosol that \\
the Riverbank i
limited by the l
penetration eff-C
Break widths ix.
the county soil
narrower then ti

A differ.
fluvial fans may.
nonhem fluvial
The KRF exhib;
indicating that tl
then the TRF an.

MOdS may hat

 

Lastly, differences in the accuracy of the county soil surveys may have prevented
the identification of paleochannels in the northern fluvial fans. The soil surveys were not

developed by the same authors and may vary in their degree of accuracy.

CONCLUSIONS

Ground penetrating radar was able to effectively track the regional lateral extent
of near-surface Riverbank paleosols on the KRF, TRF and MRF. GPR was also able to
identify erosional breaks through the paleosol on the KRF, which were created as
paleochannels switched across the upper fluvial fan surface during glacial periods. The
paleosol that was tracked by our GPR surveys represented the top-bounding surface of
the Riverbank Formation. Although the depth of penetration of the radar signal was
limited by the Riverbank paleosol, discrete increases in the depth of GPR signal
penetration effectively highlighted the location of erosional breaks through the paleosol.
Break widths identified using GPR correlate with locations of paleochannels observed on
the county soil surveys, yet the widths observed on the GPR profiles tended to be
narrower then the widths observed on the county soil surveys.

A difference in the number of erosional breaks in the paleosol between the two
fluvial fans may indicate that there are different controls on sedimentation between the
northern fluvial fans (TRF and MRF) and the southern fluvial fans (KRF in particular).
The KRF exhibits exceptionally more erosional breaks then the TRF and MRF, possibly
indicating that the Kings River was more apt to aggrade and switch its channel location
then the TRF and MRF. Factors that control channel aggradation/switching during glacial

periods may have differed between the two fluvial fans. The ratio of sediment supply to

33

discharge. dii
diliering Sit?”

diflerence bet'

 

 

discharge, differing valley subsidence rates (more in the south, less in the north), or
differing Sierran drainage areas may be areas to focus further research to understand the

difference between the two fluvial fans.

34

This chapter \i

research:

 

Additional]y

picking 0i th

PreV
alOng with :
ground‘Den
indix-idUal 5
Paieosm. II
Rhierbank

To

groundtrut

CHAPTER THREE

OTHER GPR OBSERVATIONS

This chapter will focus on the following observations made during the course of this
research:
0 Observations leading to an attempt to identify radar facies above the
Riverbank paleosol at the Kearney Agricultural Center, Orchard Site.
0 Observations that provide ground truth information about the Riverbank
paleosol at the Kearney Agricultural Center, Orchard Site.
0 Observations of topography on the paleosol at the Kearney Agricultural
Center Orchard Site and at the regional scale, as described in Chapter 2.
Additionally, a brief discussion is included that outlines an attempt to automate the

picking of the paleosol breaks.

TESTS AT THE KEARNEY AGRICULTURAL CENTER

Previously collected core and detailed studies at the Kearney Agricultural Center,
along with access to a former nectarine Orchard Site, allowed for the opportunity to use
ground-penetrating radar (GPR) measurements as a tool to potentially differentiate
individual sediment facies above the shallow regionally laterally continuous Riverbank
paleosol. It also provided valuable ground truth about the reflection characteristics of the
Riverbank paleosol.

To test our ability to recognize near-surface facies pattern as well as present

groundtruth information that supports paleosol interpretations made in chapter 2, GPR

35

data were col.
University 01~
was fomierl)
rows of trees ‘
been removed

investigations

 

 

data were collected at the Kearney Agricultural Center (KAC), an extension of the
University of California, located southeast of Parlier, CA. The study area within the KAC
was formerly an approximately one-hectare nectarine orchard plot that consisted of 15
rows of trees with 15 trees per row planted in 1975 (Figure 3.1). The trees have since
been removed and the area is now the site of ongoing vadose zone hydrostratigraphic

investigations (Harter et al., 1999).

Kearney Agricultural

   

Orchard Site

 

, “r .
5- Qinusehoed .

Figure 3.1 Map showing the location of the KAC on the KRF. Aerial photo shows location of
former nectarine Orchard Site within the KAC. (Aerial photo from wwwMapgmestcom, KRF
image fi'om 30m USGS Digital Elevation Model)

36

 

Kearney A3"
lnterc

grown in re 5?
. l:
contaminant 1‘
ese sedimen

is controlled b

over the fluVia

 

GPR h;
distributions 0
2991;101 and f
1996; Van 0V:
in lithology re:
character (radii
1993: Van OW

Thecoi
GPR profiles c
053 reflection ]

O‘f‘fmeeren‘ l'
tit-hose Charade
signatures ( pat t
S“amazed b}.
S'Ome Prob]
Hus

age
“bergEr (]

Ems ‘

Kearney Agricultural Center: Radar F acies
Interest in the architecture and complexity of these fluvial fan sediments has

grown in response to the need for an improved understanding of groundwater flow and
contaminant transport in these fluvial fan aquifer systems. Hydraulic conductivities in
these sediments are primarily controlled by sediment grain size and sorting, which in turn
is controlled by the dynamic fluvial systems that selectively sort and distribute sediments
over the fluvial fans of the Central Valley of California.

GPR has been shown to be an excellent tool when attempting to determine
distributions of sedimentary structures (e. g. Davis & Arman, 1989; Beres and Haeni,
1991; Jol and Smith, 1991; Smith and J01, 1992; Olsen and Andreasen, 1994; Jol et al.,
1996; Van Overrneeren, 1998) and lithologic variation in clastic sediments. This variation
in lithology results in differing reflection patterns, thus making it possible to relate radar
character (radar facies) to lithofacies distributions (Beres & Haeni, 1991; Huggenberger,
1993; Van Overrneeren, 1988; J akobsen & Overgaard, 2002).

The concept of radarfacies is implemented in the description and interpretation of
GPR profiles collected in this study. This concept is defined as the sum of characteristics
of a reflection pattern produced by a sedimentary unit (Beres and Haeni, 1991; Van
Overrneeren, 1998) or a three-dimensional sedimentary unit composed of reflections
whose characteristics differ from adjacent units (Huggenberger, 1993). Reflection
signatures (patterns) that relate to lithologic and stratigraphic characteristics are
summarized by Beres & Haeni (1991), yet Huggenberger (1993) shows that there may be
some problems with the transferability and generalization of such signatures.

Huggenberger (1993) explains that when attempting to identify radarfacies one must

37

remember
Smith. 199
interpretin,
events and
In t

the MC. c
stud}; (Han
summer of
cores dovvr
dniling tec}
sediments 1
USDA-SC:
grain-size a
sediment 51
Turlock La‘
C135 Coatini
Five
silt'silt loan
bEEi‘descri
see Haney E

The

Hamenis, i

remember that the reflection pattern depends on the central frequency applied (J 01 &
Smith, 1991). Additionally, the degree of saturation is an important factor when
interpreting reflection patterns. Lastly, a single reflecting surface will produce multiple
events and therefore care must be taken during interpretation.

In order to assess the ability of GPR to detect facies changes in the sediments at
the KAC, detailed logs from core collected for use in a vadose zone nitrate contaminant
study (Harter et al., 1999) were compared with GPR measurements collected during the
summer of 2002. During the nitrate study by Harter et al. (1999), 59 continuous sediment
cores down to a depth of 15.8 m below the surface were obtained using a direct-push
drilling technique within the nectarine Orchard Site. Description of the fresh-drilled
sediments focused on (1) the determination of the major textural classes according to the
USDA-SCS 1994 Field Estimation, (2) color using the Munsell Soil Color Chart, (3)
grain-size and degree of roundness for sands and gravels, and (4) description of the
sediment structure (Harter et al., 1999). The Riverbank (Hardpan 1 in figures 5 & 6) and
Turlock Lake (Hardpan 2 in figures 5 & 6) paleosols were identified by color, presence of
clay coatings, root traces, aggregates, and cementation features (Harter et al., 1999).

Five textural units were distinguished from the cores: 1) sand, 2) sandy loam, 3)
silt/silt loam/ loam/silty clay loam, 4) clay loam/clay, 5) paleosol (Harter et al., 1999). A
brief description of each of these categories follows here; for a more in-depth description
see Harter et a1. (1999).

The sand is quartz-rich, with feldspar, muscovite, biotite, hornblende and lithic

fragments, which is consistent with the granitic Sierran source (Harter et al., 1999). The

38

grains are Sui
medium gr aifl
TheS“

ofthe sandy h
of color, PresL
the sandy loan
sediments 31' e
ProximaI “00L
Silt. 51"}:
floodplain dept
variable sinCe I
to brownish gfi
Root traces and
conditions durit
The Chi}
floodplains and
traces (< mm th
clay deposits (H
Pix/€050."
tolordevelopm '
L

concretions, feu

 

relativ '
ely mature

non ‘ '
deposrtron d

 

grains are subangular to subrounded with sizes ranging from fine to coarse, but the fine to
medium grain size are dominant (Harter et al., 1999).

The sandy loam is the most frequent category observed within the profiles. Some
of the sandy loam deposits have been interpreted as weakly developed paleosols because
of color, presence of root traces as well as aggregates (Harter et al., 1999). Sorting within
the sandy loam is moderate to good with occasional thin (0.5-l cm) clay layers. These
sediments are assumed to have developed at the edge of channels, as levees, or as other
proximal floodplain deposits near the channels (Harter et al., 1999).

Silt, silt loam, loam and silty clay loam are assumed to be the proximal to distal
floodplain deposits of the KRF and are grouped together in well log descriptions as
variable since they vary laterally (Harter et al., 1999). They are usually slight olive brown
to brownish gray with bed thickness ranging from a few cm to dm (Harter et al., 1999).
Root traces and rusty brown colored spots are quite common and indicate oxidizing
conditions during some periods of time (Harter et al., 1999).

The clay and clay loam sediments are assumed to be deposits in the distal
floodplains and in ponds that developed in abandoned channels (Harter et al., 1999). Root
traces (< m thick) as well as rusty brown spots are observed quite frequently in these
clay deposits (Harter et al., 1999).

Paleosols exhibited different stages of maturity, typified by varying degrees of
color development (Harter et al., 1999). Most exhibited aggregates, ferric nodules and
concretions, few calcareous nodules and hard, cemented layers (Harter et al., 1999). The
relatively mature paleosols formed during periods of stasis marked by non-erosion and

non-deposition during the interglacial periods (Harter et al., 1999; Weissmann 1999;

39

\i’eissmann c
{Harter et al..
Sedini

I

categories in t
ofsund. sand"

the scale of th

vvhich is ObSC‘I

GPR d;

to match the gr

I.

“hire 1 7 ~.

UPR Dr”: (JP ‘ r
In f l

 

Weissmann et al. 2002a). Paleosol thickness at this site ranges from 50 cm to about 2 m
(Harter et al., 1999).

Sediments on top of the Riverbank paleosol have been separated into two
categories in the well logs, the first of which is the variable category that contains a mix
of sand, sandy loam, silt, silt loam, loam, or silty clay loam, all of which vary laterally at
the scale of the study site. The second category is predominately sand to sandy loam,

which is observed to be laterally continuous at the scale of the study site.

GPR METHODOLOGY
GPR data were collected along a grid that was established at the Kearney field site

to match the geometry of the rows of nectarine trees once planted there (Figure 3.2).
Y9t - —m: : .s; T-rv-v-rr- -

' slat .tt

 

 

 

 

 

 

 

 

 

 

 

 

 

 

X51
Legend
0 510 20 3O 4O
GPR SEE Meters

Profile

Borehole Location

Figure 3.2 GPR grid established at the Kearney Agricultural Center Orchard Site. Lines represent
GPR profile locations, and points represent well locations. The GPR profile from line Y91 is
shown in figure 3.5, and the GPR profile from line X5] is shown in Figure 3.6. Offset in the lines
a result of field conditions and equipment setup during the time of data collection.

40

 

 

w-

E

{\x 2,-

'h

I
I

F r

.
v. a; -—.

figure 3.3 C0
the back ofth

The system i
for COmmox
antenna 38p;
Antennas ha
anal-“ES (St:
surfaCe GP}:
Profiles (Jol
vii'INEKKO
@Piied to th
Slowly deem

alum“, re

This resulted in a total of fourteen profiles, seven in both the south-north and west-east
directions. The GPR profiles passed as close as possible to bore hole locations used in the
Harter et al. (1999) nitrate study.

The GPR system employed in this survey was the pulseEKKO 100““, which was

towed behind a tractor to facilitate rapid data collection (Figure 3.3).

 

Figure 3.3 Collecting GPR data in the former nectarine Orchard Site. GPR equipment attached to
the back of the tractor.

The system was operated in reflection survey mode with a signal stacking of 8 times (32
for Common mid-point (CMP)), a step size of 0.5 m (triggered by odometer wheel) and
antenna separation of 2 m (maintained by a fiberglass GPR cart towed behind the tractor).
Antennas having center frequencies of 50 and 100 MHz were utilized. Two CMP
analyses (50 and 100 MHz) were completed, allowing for the estimation of the near-
surface GPR wave velocity (0.14 m/ns) needed to develop depth scales for the GPR
profiles (Jol and Smith, 1991) (Figure 3.4). Profiles were processed and plotted using
WINEKKO (version 1.0) and EKKOMAPPER (version 2). Minimal processing has been
applied to the raw GPR data, and consisted of dewow, a time filter which removes any
slowly decaying low frequency “wow” which may become superimposed on higher

frequency reflections.

41

 

 

Figure 3.4 Cor
tor a more in d

GPR PTO/Ha
In the

Both PrOfiles
area. A pro it
relatively 10‘
retained SOn
“'9 Iime of(
The
Second Prof:
MHZ (top) a
on both Prot

tillhin the n!

 

Figure 3.4 Conducting a CMP experiment at the KAC Orchard Site study site (See chapter two
for a more in depth description of CMP experiments).

GPR Profiles: Descriptions of Radar F acies
In the following section, two of the fourteen GPR profiles collected are presented.

Both profiles contain data collected in the near—surface unsaturated zone of the study
area. A prolonged period without rain in the Central Valley implied that there was
relatively low water content in the unsaturated zone, yet fine-grained materials may have
retained some degree of saturation. No measurements of water content were collected at
the time of GPR data acquisition.

The first profile (Figure 3.4) is a west-east section that is 86 m in length. The
second profile (Figure 3.5) is a south-north section that is 90 m in length. Both the 100
MHz (top) and 50 MHz (bottom) surveys are shown in each figure. Reflections observed
on both profiles become less distinct with increasing depth due to signal attenuation

within the near-surface, clay rich, Riverbank paleosol located between 3 and 5 m depth.

42

Well L
‘l
i

 

>
V

Depth In Meters
BESESISmosswo
' ' ' inhuman-nu

22

 

 

Figure 3
kited V
Section (
lg and 4

anaIE'Sis

Well Log Legend

   

Sandy Loam

- Variable

l Paleosol (Hardpan 1)
Sand

Clay-Silt- Loam Mix

Paleosol (Hardpan 2)

Clay

Interpreted Location of Paleosol

Y91 Depth Section at 100 MHz

53

Depth In Meters
o 353; SS oom-hwo

NN
N

0 1o 20 30 4o 50 60 7o 80
Position In Meters

 

 

 

B) Y91 Depth Section at 50 MHz

0_ I o

2— 2

a 43’ -4
§ 6‘ 6
E 8 8
510 10
.c 12 12
5.14 14
316 16
18 18
20 20
22 22

0 1o 20 30 4o 50 60 7o 80

Position In Meters

Figure 3.5 West-East GPR profile from the Orchard Site at the KAC with described well logs.
Dotted yellow line sits on the reflector interpreted as the paleosol. Note that in the 50 MHz
section (B) the ground wave arrival is overprinting the paleosol reflection between approximately
19 and 46 m. A velocity of 0.14m/ns was used in GPR profile depth correction from CMP
analysis at the KAC. Profile locations are shown in figure 3.2. *This image is presented in color.

Well

 

111'.

4.4411141111111110 11
0246000246802 ed..m..n.m
1.122 Tmtwdoé

..1.avcl..

 

Eiiulfiihn. _ . .. _ . .
0246802468mn \i/ m a Q
_. gmmzettu 03

\I
A 305:). C. £~QUO

Well Log Legend

Sandy Loam
Variable
Palegsol (Hardpan 1) Interpreted Location of Paleosol

an
Clay-Silt- Loam Mix
Paleosol (Hardpan 2)

Cl
A) 3’ xs1 Depth Section at 100 MHz

 

0 1o 20 3o 40 so 60 7o 80 90
Position In Meters

 
  

B) X51 Depth Section at 50 MHz
0
2
W
E 4
a, 6
E 8 8
C
-10 10
512 'Wmmwme-MWI.~W:v.~—z
814 Mkfifi.mw-v'WA~uh-“‘a‘bl "UAW 4.1””
D16 ‘9'“ -»-."-'r.----"---Juan-Wag. ’ _ ' . " ' -15
18 .8 18
20 20

0 10 20 30 40 50 60 70 80 90

Position In Meters

Figure 3.6 South-North GPR profile fiom the Orchard Site at the KAC with described well logs.
Dotted yellow line sits on the reflector interpreted as the paleosol. A velocity of 0.14 m/ns was
used in GPR profile depth correction from CMP analysis at the KAC. Profile locations are shown
in figure 3.2. *This image is presented in color.

44

A 115

 

no indicalion
Paleosol- Duk
information i‘

[31'th amval

 

l
The I“

ijerbank pal
changes in fac
sections “her
close to the SL

What 1
occum'ng as 3
properties, or
measured. the
boreholes rela
utilized, idem

threat data 56

chamehshape

‘

“QR
r: \58

m that an

(3‘1 . .

Cl;

A visual comparison between the GPR profiles and the overlain well logs shows
no indication of a correspondence between reflection patterns and the well logs above the
paleosol. Due to the fact that the paleosol at the site is very shallow, limited signal
information is preserved in the near surface since much of the signal is being overprinted

by the arrival of the airwave and the ground wave.

RADAR FACIES CONCLUSIONS

The two categories as defined by Harter et al. (1999) for the sediments above the
Riverbank paleosol, variable and sandy loam, appear to be too generalized to interpret
changes in facies based on the GPR reflection signal. This can be noted in the 50 MHz
sections where the airwave and ground wave are being overprinted on the reflection data
close to the surface.

What can still be drawn from the GPR data collected is that reflections are
occurring as a result of either a change in lithology between units of contrasting electrical
properties, or a change of water content within the same unit. Since water content was not
measured, the well logs lack adequate detail, uncertainty exists in the location of the
boreholes relative to the GPR lines, and higher frequency antennae (>100 MHz) were not
utilized, identification of radar facies at the KAC Orchard Site was not possible using the
current data set. The GPR profiles, however, do contain elements that appear to be
channel-shaped indicating potential channel facies, thus interpretable radar facies may be
present that are not directly correlative to the boreholes due to uncertainty in their

positioning relative to the GPR profiles. Future work attempting to identify radar facies at

45

at the .'

interpr

therefo

the larg
new;
and sub
the Well
Site. L751
that l‘ollc
Shows lh

demon

this site should include higher resolution antennae (200 MHz or higher) in combination
with more rigorous groundtruth information in the form of accurately located well logs
with highly detailed lithologic descriptions. Taking these steps would potentially allow

for a more rigorous investigation into the identification of radar facies at this site.

PALEOSOL GROUNDTRUTH AT THE KAC

Although it was not possible to identify radar facies above the Riverbank paleosol
at the KAC using the data collected, the data do provide the opportunity to make
interpretations about the ability of GPR to identify the paleosol. The GPR data can
therefore be used to provide reliable evidence that supports our interpretations made in
the large-scale regional study discussed in chapter 2. Well logs collected by Harter et al.
(1999) provided much needed groundtruth information about the depth to, thickness of,
and subsurface character of the Riverbank paleosol. Referring back to figures 3.5 & 3.6,
the well logs show the depth to and thickness of the Riverbank paleosol at the Orchard
Site. Using the well logs as a guide it is possible to follow a nearly continuous reflection
that follows the top of the paleosol identified in the well logs (Figures 3.5 & 3.6). This
shows that the paleosol is providing a good reflection that can be traced and that the
depth of signal penetration is limited due to the paleosol’s clay-rich nature.

One observation that was made that was not expected at the Orchard Site was the
amount of signal penetration into the paleosol. In our regional study we assumed the GPR
signal was essentially fully attenuated once it had encountered the Riverbank paleosol. At
the KAC, the GPR data seem to indicate that the signal penetrated into or slightly through

the paleosol. This may be due to the fact that the GPR signal is not penetrating through

46

roadbed mate
the surface. E
therefore we
water from in
high tempera!
the paleosol a
made too 5001
information in
Sl:e’l’lature of th
Orchard Site 5

SLiPPoning inn

The las

scale And has 1.1

Sun-{3.5 We not;
der

€i0ped frOn‘

the paleosol i s I

 

um topographi ,

be . .
lOLEillOnS “'h-

“‘1

“‘“d at these l0
&

143. ,
.Ddleosol int
(,1

 

roadbed material at the Orchard Site. Also, the paleosol at the KAC is relatively close to
the surface. Being that it is close to the surface, it may have lost moisture content,
therefore providing less signal attenuation then in other areas that may have received
water from irrigation, or have been deep enough to avoid desiccation as a result of the
high temperatures in the Central Valley of California. Conversely, our assumption that
the paleosol attenuated our signal completely in the regional-scale study may have been
made too soon and without adequate groundtruth information. Therefore, groundtruth
information in the form of accurate well logs may be necessary to fully understand the
signature of the paleosol in the regional scale study. Ultimately, the results from the
Orchard Site show that it is possible to track a near-surface paleosol using GPR,

supporting interpretations made in chapter 2.

PALEOSOL TOPOGRAPHY

The last observation made at the KAC Orchard Site was also made at the regional
scale and has important implications for firture groundwater modeling studies that aim to
incorporate the effects of the regionally continuous paleosols into their models. In our
surveys we noted that the paleosol surface exhibits subtle topography. Cross-sections
developed from the KAC Orchard Site well logs as well as the GPR profiles indicate that
the paleosol is not a perfectly planar feature. This observation therefore leads to the idea
that topographic lows on a hydrostratigraphic-confining layer within the vadose zone will
be locations where water/contaminants will migrate to and build up. Once the hydraulic
head at these locations becomes high enough, water/contaminants will be forced through

the paleosol into the deeper aquifer units (Figure 3.7). Jury et al. (1991) explain this

47

phenomenon
unsaturated /

I
layer to fill. t
wwnmmnr

dereloping g:

topographic l1

 

 

Figure 3.7 Sel‘
dfpfessions in

c0xc1
GPR

CPR to deter

the Characte.
351W” 33 1L1
[0

pggl'aphV

“lilac e

phenomenon in layered systems, whereby raising hydraulic head values in the
unsaturated zone due to infiltration allows the pore spaces in the hardpan or clay rich
layer to fill, thereby allowing flow through the paleosol to occur. Therefore, the
observation of topography on the paleosol surface has significant implications when
developing groundwater models to simulate fluid flow in these systems since these

topographic lows will be spatially significant recharge locations.

Land Surface

 

Infiltration
Lateral Fluid Migration

______.____..__.—_-__..

,_ A Paleosol“ llllllll

Recharge

   

Figure 3.7 Schematic diagram depicting preferential recharge as a function of topographic
depressions in the near-surface paleosols on Central Valley fluvial fans.

CONCLUDING REMARKS FOR FUTURE WORK ON RADAR FACIES

GPR data collected at the KAC provided the opportunity to explore the ability of
GPR to detect facies changes in near-surface sediments, verify interpretations made about
the character of the Riverbank paleosol in a setting with good ground truth information,
as well as identify and explore the idea that the Riverbank paleosol exhibits subtle
topography which may focus recharge to topographically low spots on the paleosol
surface.

With regards to the identification of radar facies, higher frequency antennae (200
MHz or greater) combined with detailed lithologic well logs should provide the means to

identify reflection patterns indicative of a facies change in the near surface. Considering

48

me fact that
area in whicl
paleosol to b
different faci
profiles COUiL
in the near 511
2) allow for ll
intervals to in
near surface s

ftuther researt

OL'R ,

In an a
GPR Profiles,
Process. To do
13er “"215 215513.
hm .
“emf? horse

“Sing the “IOeq :

“ere
[hen piOII;

 

1,35 hoped [b |

@3101} Of are
it

 

the fact that the paleosol is so shallow at the KAC, it may also be advantageous to find an
area in which the paleosol is slightly deeper. This will allow for more data above the
paleosol to be collected in the hopes of better understanding the reflection patterns of the
different facies observed. Lastly, establishing a highly detailed survey grid of GPR
profiles could potentially allow for three-dimensional visualization of facies distribution
in the near surface at the KAC. Newer software packages (e. g. EKKOMAPPER version
2) allow for the visualization of GPR block models that can then be sliced at various time
intervals to image different portions of the subsurface. The KAC Orchard Sites variable
near surface sediment distribution may provide an excellent area in which to conduct

further research using GPR.

OUR ATTEMPT AT USING MATLAB TO PICK PALEOSOLS AND
ASSOCIATED EROSIONAL BREAKS

In an attempt to expedite the process of interpreting approximately 190 km of
GPR profiles, a MATLAB script was developed which attempted to automate the
process. To do this, each GPR trace was normalized within MATLAB and then a cutoff
value was assigned which represented the value at which the GPR signal had essentially
become noise. Once all of these values had been calculated, the data were then smoothed
using the “loess” smoothing function (quadratic fit) in MATLAB. The smoothed data
were then plotted on top of the corresponding GPR profile (Figure 3.8). Once completed
it was hoped that the smoothed data would show the depth to paleosol along with the

location of areas of increased penetration depth along the GPR profiles.

49

0

Depth in Meters
61

 

20

25

figure 3.8 E,

develOped 10
color.

As c
P101116, a go
SI'Snztls and 1
deplh to pale
that Were ell
Script to lder
when it Was .
being made S
dfia failed to

IECl that [he 5

Tamed the Cl

Lincoln Road Segment 12

Depth in Meters
G

20

 

25
0 500 1000 1500 2000 2500 3000 3500
Position in Meters

Figure 3.8 Example of smoothed data plotted on top of GPR profile using the MATLAB script
developed to pick the trace values at which the signal goes to noise. *This figure presented in
color.

As can be see in Figure 3.8, once the smoothed data was plotted onto the GPR
profile, a good representation of the character of the interface between true reflected
signals and noise was observed. With these data, we had hoped to assign a value for the
depth to paleosol and use another MATLAB script to assign different categories to values
that were either above or below the depth of paleosol, and then use the output from that
script to identify erosional breaks in the paleosol. Difficulty arose during this process
when it was noted that the smoothed data did not coincide with interpretations that were
being made simply by eye. For instance, in figure 3.8 between 0 and 250m the smoothed
data failed to envelope the obvious deep reflector in that interval. This resulted from the
fact that the MATLAB script was not complicated enough to rule out values in traces that

reached the cutoff threshold sooner then expected. It was also noted that assigning a

50

constant ml
or no break.
of missing 5
paleosol. we
time it was I‘
MATLAB SL
appendices a

research.

 

constant value for the depth to paleosol as a cutoff value for the interpretation of a break
or no break, would, in the case of overestimation the depth to paleosol, have the potential
of missing shallow breaks in the paleosol, and in the case of underestimating the depth to
paleosol, would over estimate the true number and width of the breaks. Therefore, at this
time it was more efficient and reliable to interpret the GPR profiles manually. The
MATLAB script that was prepared to create the smoothed data is included in the
appendices as are other MATLAB scripts that were developed during the course of this

research.

51

PAL

multiple
3003a).
mid- ant
possible
deposits
unable It

regional

ERO:

Obsen'ed
breaks u
Sung}- IT
illat fadiz
[thUgh 1

Kat.

muffin.

CHAPTER FOUR

THESIS CONCLUSIONS

PALEOSOLS AS REGIONALLY LATERALLY CONTINUOUS FEATURES
Fluvial fan deposits within the San Joaquin Valley of California consist of

multiple sediment sequences separated by unconformable surfaces (Weissmann et al.,
2002a). The unconformable surfaces can be identified by paleosols that formed on the
mid- and upper-fluvial fan surface during times of depositional hiatus. Using GPR, it was
possible to trace the lateral continuity of the uppermost paleosol, capping the Riverbank
deposits in the subsurface of the KRF, TRF and MRF. Unfortunately, at this time we are
unable to ascribe an accurate depth to the paleosol based on the GPR data due to a lack of

regional scale groundtruth information.

EROSIONAL BREAKS IN THE LATERALLY CONTINUOUS PALEOSOLS

On the KRF discrete breaks in the continuity of the Riverbank paleosol were
observed on GPR profiles collected across the mid- and upper fluvial fan surface. These
breaks correlate well with observed paleochannel locations noted on digitized county soil
survey maps that highlight c-horizon textures. Therefore, it appears that paleochannels
that radiated from the apex of the KRF during the deposition of the Modesto unit incised
through the Riverbank paleosol, thus interrupting the continuity of this paleosol on the
KRF.

Further north on the TRF and MRF, we had expected to observe similar erosional

features. Yet on the TRF the paleosol appears to be missing these erosion features. This

52

seems to be
the most rec

River appca

 

ability to en

On tl
eolian depos
obscure potc

from paloch.

RAD

 

 

Fifty—
orchard at the
prOlllES (SCH:
attempt idem.
Sfdiments ab<
t0 tllIECIIy C0
Complication
disc”PU-Ons.
Elaante fame

GPR profiles.

seems to be due to minimal lateral migration of the Tuolumne River paleochannel during
the most recent glacial outwash event (e. g. Modesto deposition). Since the Tuolumne
River appears to have maintained its channel position during Modesto deposition, its
ability to erode through the Riverbank paleosol was limited.

On the MRF, erosion breaks were difficult to identify due to relatively thick
eolian deposits in the area in which the GPR data were collected. The dunes tended to
obscure potential erosional breaks due to the fact that they could not be differentiated

from palochannel deposits on the MRF county soil surveys.

RADAR FACIES AT THE KEARNEY AGRICULTURAL CENTER

Fifty-eight continuously cored and described wells within a former nectarine
orchard at the Kearney Agricultural Center (KAC) combined with a grid of 14 GPR
profiles (seven west-east and seven south-north profiles) provided the opportunity to
attempt identification of characteristic radar reflection patterns for various facies in
sediments above the Riverbank paleosol (see Chapter 3). Unfortunately, we were unable
to directly correlate any facies changes observed in the well logs with the GPR data.
Complications with radar facies interpretations were the result of (l) generalized well log
descriptions, (2) GPR antenna frequency, which was too low for the detail necessary to
evaluate facies so close to the surface, (3) inaccurate borehole location with respect to

GPR profiles.

53

geoph
used I
that th
identil
cones;
by the
their C
data in
at this .
3 good

0% Slt

PALEOSOL GROUNDTRUTH INFORMATION

Groundtruth information for this study was obtained at two different locations.
The first being data collected for a USGS study by Burrow et al. (1997) that was located
near where we had collected GPR data for this study. Burrow et al. (1997) collected
geophysical data in the form of continuous seismic profiling, and GPR data that were
used to identify laterally continuous fine-grained layers (unknown at the time was the fact
that they were tracking sequence bounding paleosols). In their study they successfully
identified a laterally continuous subsurface reflector on their GPR profiles that
corresponds to the Turlock Lake paleosol, which in most cases in our study was obscured
by the presence of the Riverbank paleosol that sits above it. We were able to compare
their GPR results and well log groundtruth information to our own since we had collected
data in the same vicinity. Assuming that we are correctly identifying the depth to paleosol
at this site (assumed to be the point at which the signal is completely attenuated), we see
a good correlation between the Turlock Lake paleosol observed in USGS study and our
own study.

The second site at which we have groundtruth information is at the KAC
nectarine orchard site. At the KAC, continuously collected and described core provided
the opportunity to groundtruth our observations of the paleosol on the GPR profiles with
described borehole data. This work showed that it was possible to identify the paleosol
reflection within the GPR profiles. Yet, we remain uncertain about our ability to show the
exact depth of the paleosol reflector. Correlation between the observed paleochannels on
the digitized soil surveys and the GPR profiles supports the hypothesis that breaks exist

and that GPR data were able to identify these features, therefore we feel that we were

54

also able to
this time.
COMP
The
which were
I
obvious of 1‘-
3,150 kmi. \

km'.F:ti1 arc

 

 

 

when compa
fans (approx
asume that '
suggested he
level. there f«

to bypass th

also able to trace the extent of the laterally continuous paleosols but not the true depth at

this time.

COMPARE AND CONTRAST BETWEEN THE THREE FLUVIAL FANS

The three fluvial fans studied exhibit notable morphological differences, some of
which were observed in the county soil surveys and the GPR data collected. The most
obvious of these differences is fan size, with the KRF being the largest with an area of
3,150 kmz, while the TRF has an area of 576 kmz, and the MRF having an area of 552
kmz. Fan area has been described as a function of drainage basin area (Harvey, 1989), yet
when comparing drainage basin areas it is noted that little difference exists between these
fans (approximately 394 km2 between the KRF and TRF) (see Chapter 2). Therefore, we
assume that the fan areas differ due to a control other then drainage basin area. It is
suggested here that TRF and possibly the MRF may have been adjusted to eustatic sea
level, therefore allowing sediment that would have been deposited on the TRF and MRF
to bypass these systems by way of the San Joaquin delta. The KRF adjusted to the Tulare
Lake Sub-basin to the south and appears not have been affected by eustatic sea level
change.

The last obvious difference between the fluvial fans was observed in the GPR
data. The number of erosional breaks through the paleosol observed on the fluvial fans
differed, with the KRF having the largest occurrence of breaks. The TRF lacked any
major erosional breaks, while MRF paleochannel identification was difficult due to eolian
deposits, which complicated our ability to make accurate interpretations without further

GPR data and well log information.

55

FUTURE CONSIDERATIONS

Future work that may further support the conclusions reached here would include
collection of additional groundtruth information then was provided in this study. Due to
the large-scale nature of this study, it was impossible during acquisition of the GPR data
to collect physical subsurface groundtruth information. The GPR profiles include
questionable areas that could not be interpreted without further information about the
character of the subsurface. If core had been collected in those areas, fewer questionable
areas might exist along our GPR profiles and our understanding of these fluvial fans
systems might be greatly enhanced.

Another consideration to further enhance the results of this study would be the use
of higher GPR frequencies. This may have provided more detail in both the regional
study and our attempt to identify radar facies at the KAC orchard site. Since the paleosol
observed on the fluvial fans is a relatively shallow feature, more information could be
collected about the character of the sediments above the paleosol using higher frequency
antenna. Although we used 50 MHz antennae to maximize depth of penetration when we
encountered a deep erosional incision, it limited valuable near surface detail in the GPR
profiles thereby hindering the interpretation of radar facies and paleosol reflection
character. In many instances, the ground wave and airwave tended to overprint their

signatures on top of data that would have shown the paleosol or facies changes.

56

APPENDICIES

57

Appendix A

58

Kings River Fluvial Fan GPR Profiles

Smith Road Merged Profiles 34-39

Depth in Meters

onDepth in Meters

o 20::

an

_... ”:3 5.

r: “—321...

warm—fie wmQBmsn d

 

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comic: _: 2.3m;

moS:

 

Figure A1 Segments l & 2 of merged Smith Road profiles 34-39.

59

Smith Road Merged Profiles 34-39 (Cont)

o 20:: mafiamwwo $933 w moS:

  
 

A

Depth in Meters

88 some 38 two 88 $8 $8
bongo: 3 Zmnma

Figure A2 Segment 3 of merged Smith Road profiles 34-39.

60

Smith Road Merged Profiles 40-43

Depth in Meters

Depth in Meters

20:: mmoohmow mmmamsn o

 

,. it . . 5.532? tat-Scai.‘ w.‘§.§3...... «9 .3333

.. .... 5.351.... . 1.2:; . of. .
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Figure A3 Segments l & 2 of merged Smith Road profiles 40-43.

61

Smith Road 1 & 2 Merged

Depth in Meters

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w ...

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62

Smith Road 1 & 2 Merged (Cont.)

Depth in Meters
0‘

k N
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Sia1aw ul uougsod

0527

Figure A5 Segment 3 of merged Smith Road profiles 1 & 2.

63

 

”MON 0

s 1U9UJ5BS z m peou ullws

0 W105

Del Rey Road Merged Profiles 11-15

202.: , .. . , . ,OmImemoBmJZ moo”:

Depth in Meters

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v8.20: _: _Smnmd

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Figure A6 Segments 1 & 2 of merged Del Rey Road profiles 1 1-15.

«LAXX. a.\..3
wuhv.v.n.0qd .1. gal-HAW‘fl

 

Del Rey Road Merged Profiles 11-15 (Cont.)

203: .. . . . .mumh....mmmcgm.dn:w. . . moi:

     

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.31....LéaQT.
88 SS

1830: _3 2.32m

 

               

Figure A7 Segments 3 & 4 of merged Del Rey Road profiles 11-15.

65

Del Rey Road Merged Profiles 16-20

Depth in Meters

Depth in Meters

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alesatf...

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Figure A8 Segments l & 2 of merged Del Rey Road profiles 16-20.

66

Del Rey Road Merged Profiles 16-20 (Cont.)

20:: Oz. mbo wmmBmZ w

0

Depth in Meters

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67

Highland Road Profile

Depth in Meters

moo

do 88
10.0.30: _: Zmflma

20::

.moc

o

 

Figure A10 Highland Road Profile (EU 1).

68

Del Rey Road Merged Profiles 31-33

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22... . . mos... m... .- .. .22..

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Figure All Del Rey Road Merged Profiles 31-33 (100 MHz).

69

Lincoln Road Merged Profiles 11-13

Depth in Meters

Depth In Meters

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2...... ......

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Figure A12 Segments 1&2 of Lincoln Road Merged Profiles 1 1-13.

70

Lincoln Road Merged Profiles 11-13 (Cont.)

r2. d; w $032: w 22»

      
 

Depth in Meters

08 mnmo mmoo 38 @000

88 $8 $8 53 m
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71

Lincoln Road Merged Profiles 11-13 (Cont.)

Depth in Meters

Depth in Meters

.owmo

flomoo

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coco o~mo

v8.20: .3 2383

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Figure A15 Segments 7&8 of Lincoln Road Merged Profiles 11-13.

73

Lincoln Road Merged Profiles 11-13 (Cont.)

Depth in Meters

0 CD 0\ A N

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Figure A16 Segment 9 of Lincoln Road Merged Profiles 11-13.

74

1523 0

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Bethel Road Merged Profiles 2-3

203: .7 . mm”: N-w mac—52: a

 

Depth in Meters

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Figure A17 Segments 1&2 of Bethel Road Merged Profiles 2-3. Segment two (O-660m) corrupt.

75

Bethel Road Merged Profiles 2-3 (Cont.)

Depth' In Meters

Depth in Meters

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Figure A18 Segments 3&4 of Bethel Road Merged Profiles 2-3.

76

Bethel Road Merged Profiles 2-3 (Cont.)

Depth in Meters

05£8 0058 0528 0008

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Figure A19 Segment 5 of Bethel Road Merged Profiles 2-3.

77

 

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Lilnos

Dinuba Road Profile 3

my: 93 ...-.333» A

 
      

Depth in Meters

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North Road Profile 1

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Figure A21 Segments 1&2 of North Road Profile 1.

79

North Road Profile 1 (Cont.)

2023 mmoBmsn w

Depth in Meters

.88 sdo $8 sdo m8o ddo d8 “do
wanna: _... 2583

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V r

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or?! amiaz {3.1.5

. 4“

Depth in Meters

 

88 ado
bongo: _: 2583.

Emma

 

Figure A22 Segments 3&4 of North Road Profile 1.

80

Indianola Road Profile 3

Depth in Meters

:65 w

4 I

 

i _ 1;: ._ V3:

 

do moo do 38 .do Goo
_uomEo: _: Zmfimd

Figure A23 Indianola Road Profile 3.

81

Annadale Road Profile 1

Depth in Meters

Depth in Meters

 

o mom"

V., , 4'14... ... .-
, J... .13.. 32?...1.’ 2.11»
_

...-...»... ELK. _ ; _.. ..; ...1

>33 A mama-63 N

o mom» S3- 0

Nooo Ndo
v8.20: _: _Smnmd

>36 4 $0393

3.13:3?r3

......1- 4: 52.

58
v8.20: _: 2583

58 $00

53.3

 

Figure A24 Segments 1&2 of Annadale Road Profile 1.

82

Green Road Merged Profiles 1-2

20:: .032. T N mmmaman d moS:
o... .... .... . V .. . . .. o

 

N
B
m
e t.
M
.m .7, VV VV .. n. V
.n 2 i .V V V . ,V
t . V . V _ 0
w 3.. _ V V V V. V
D V VVV V
o
_o
o do moo do 88 do Goo . do 88
temEo: _: 2583
20:: V . Gamma-TN meBVmB N moan... o

_. a

g

Depth in Meters

.. V V V. V V RS;

 

Nooo Ndo d8 Ndo wooo odo doo wdo ..ooo
vommmo: .3 258:.

83

Figure A25 Segments 1&2 of Green Road Merged Profiles 1-2.

Green Road Merged Profiles 1-2 (Cont.)

Depth in Meters

$3.33

m . V Var.“ $21....

A. _ L . .‘3 _..!‘Q.

.

iii; §§§§§>§if
V V V i r.
Qoteffiazyfiw.

9mm: TN mmmBmB w

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. V... .. __V ... ...: 3...... .. .V
{silo.as.$§!..._....§é¥éV. .i. E...

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R500 #Nwo Amoo humo mooo

_uodEo: _: 2383

9‘

 

inegzfisg... 2x3...

mNmo mmoo

do

Figure A26 Segment3 of Green Road Merged Profiles 1-2.

84

Highland Road Profile 1 (Highl)

Depth in Meters

Depth in Meters

Numo

IE: 3 mmnamzz

88
media: .3 .5de

:6: . .mmuamg N.

wooo
v8.20: _3 .53qu

_Nwo

wNmo

.moo

.Vmo

 

 

Figure A27 Segments 1&2 of Highland Road Profile 1.

85

Highland Road Profile 1 a-Iighl) (Cont.)

Depth in Meters

053?

s-Iaiaw ul uognsod
0051;

051i?

Figure A28 Segment 3 of Highland Road Profile 1.

86

   
  

2 lueuifias 1 Wm ”ms

quN

Central Avenue Merged Profiles 1-2

Depth in Meters

moo

do

93:. TN 256mg

88
.5320: _: 2.de

<<mm~

 

Figure A29 Central Avenue Merged Profiles 1&2. Segment 2 is corrupt.

87

Butler Road Profile 1

Depth in Meters

Depth in Meters

we": 3 manna..." 3

3°00

“gonzo: _... .smnmd

  
 

Nudo
v3.20: _... .5de

men: mmo3m3 N

.ch

wooo wNmo

<<m$

  
 

c

Figure A30 Segments 1&2 of Butler Road Profile 1.

88

California Road Profile 1

Depth in Meters

Depth in Meters

9:3 $9.22: N
o mom” Emma

88 38
p830: _: .5de

o

 

9:2 $9533

88
v8.20: _: 222m

 

lel.

Figure A31 Segments 1&2 of California Road Profi

89

Church Road Profile 1

Depth in Meters

o mod"

93: 3 302m

«comic: _: _Smfimd

<<m2

...

 

Figure A32 Church Road Profile 1.

90

Dockery Road Profile 1

Depth in Meters

 
  

Gear 3 303m

moo do
woazos _: zmflmd

Figure A33 Dockery Road Profile 1.

91

Indianola Road Profile 21 (Indi21)

Depth in Meters

Depth in Meters

.31.». .2. $1.; ‘.:. a

1.33.??? . ...

Nooo NNmo

  

3&2 mama-5:: 20::

 

moo do 38 .do Goo _do 88
“.830: 5 332m

5&3 mmoaman N 20::

  

  

 

d8 Ndo wooo
v3.30: _3 2583

1e 21.

Figure A34 Segments 1&2 of Indianola Road Profi

92

Thompson Road Profile 1 (Thoml)

Depth in Meters

Nmo

moo

.233 3 302m

.1114 <1l<.l d-II

do
1830: _3 25.33

H coo

    
 

Figure A35 Thompson Road Profile 1.

93

Thompson Road Profile (Thom21)

Depth in Meters

Depth in Meters

nmo

NNmo

 
 

:83 N3 mmmBmJZ

.

H ..1 x. 5L3

. V V . . «Jere-.3313

moo umo

. . V . ..
doo Ndo
v8.30: _3 33m:

4:03 No mmo3m3 N

88 58
peace: _3 2.22m

20:: o

  

      

Figure A36 Segments 1&2 of Thompson Road Profile 21 (Thom21).

94

Kamm Road Merged Profiles 1-2

Depth in Meters

Depth in Meters

V ...}.il... 12“”...2; .

Nooo NNmo Nmoo

   
 

533 TN mmm3m3 ._

a! ...3 Vi V

 

do 88 do 58 _do Nooo
v8.20: _: Zmumd

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l ..l- o

34w: V
agififitfiiy ... V. m
gawafiggik .
V a,“

“a. 3..-e. ow . 3 o

Ndo wooo odo doo odo 88
comic: _: 2.de

Figure A37 Segments 1&2 of Kam Road Merged Profiles 1&2.

95

Kamm Road Merged Profiles 1-2 (Cont.)

Depth in Meters

.933... 3.3... .o

3830: _: Zmnmd

   

ado

5.33 TN mm03m3 w

88 $8
v8.10: _: 2583

JJ I:...:.... $55.”

”1:3?

1.... w... «1.3-(w i.

 

Figure A38 Segments 3&4 of Kamm Road Merged Profiles 1-2.

96

Nebraska Road Merged Profiles 1-3

Em: 2mg Tm mmm3m3 d

 

N V V V N
a
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VV VV .. V. V V. itsiii’f ._ . $3.13: . V . alight
m . VV ‘ .V.? }. #13:»..ffw 333.14 ‘.V..Vx!3.VV~.r_‘t+. m
. 222.1: irrigzaziiiié c

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_

0 So So do 88 :8 $8 :8 ~80
tomao: _: 25an

231%. mmm3m3 N

  
 

 

         
   

    

  

Depth in Meters

    

      

            

m _
# .. _V ‘ .. VV 5 ..4 V V
V 31. . . .1: 9.; ¥.. A? 4% V. :VVZVEQ 11%..
m t. 3511.; :v... ...ww..i:rvlfi.iir J 3: ”V5 T. V .2V V. V L! ’.VJF VV #:1711118:

 

{skaigig . V}. . V. segregates? Vti .. {gist
5 ....xiiiVT. ..V:V¥.Vr.¥w€..r_».ii§:m1£....nf! fligafiéfixww.11.}.«7:gigafii.é Jwfié. 8
: V V V r _,V V .H V V _

88 58 $8 88 88 $8 $8 38 88
_uonao: _: _Smnma

~3.

Figure A39 Segments 1&2 of Nebraska Road Merged Profiles 1

97

Nebraska Road Merged Profiles 1-3 (Cont.)

23" 2mg .-w mmoBmsn w mm:

Depth in Meters

 

88 38 a8 88 88 $8 $8 $8 88
v8.20: _3 >3an

 

 

    

o 53% 2mg. Tw $.63ng I ma" o
I] . .
'1 A 1.

N ~
8
m
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.mm. m J ....wa V , a
e
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m V. . , V V .. . 32:15:35 i,x§§78£12§.§.§‘¥1§Eik 3% m

{Vt Friifiih

8 Emaisx . . V inféifi {figxgfimgms Qfifis suaxwfiaevifiyw a

88 $8 $8 ado 38 38 d8 :8 88
bongo: _: 2583

-3.

Figure A40 Segments 3&4 of Nebraska Road Merged Profiles 1

98

Nebraska Road Merged Profiles 1—3

Emma 2mg, .Tw mmmamsfi m mum"

Depth in Meters

were; V. _..... ii}. .V..V._.%ixVi.V .r .V .3: V1.2 L: ‘.:}viar?
. V Vie V VVV.VVV§.V.V§.VVVVV -.

V,

88 $8 $8 $8 88 88
_uomEo: _: _Smfima

 

Figure A41 Segment 5 of Nebraska Road Merged Profiles 1-3.

99

Zediker Road Profile 1

N3 A 3.02m

 

  
 

 

moS:
o 203: 0
~ N
B
e
t b .
m V..\._~)VLI. .ra.V_ A
.m 55.5
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.V.. . . .V c ... . .. VV:V $8.12.; 7r. El. .. .- 3r..~.i.:t?‘ 1......5 .. {Ex-9:91..
8 _.......V. . . .. ..V.. . V . ... . 5
o wmo moo do 800 Cmo Goo :mo ~08
vOmEos _: 2383
20:: qu . 302m moan:
o o
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1r .1. \... ... .V».,r.. .f ..y 1.. ......r.
NNMO WOOD wNWO wwoo WVMO 88

“gonzo: _: 25an

Figure A42 Segments 1&2 of Zediker Road Profile 1.

100

Zediker Road Profile 1 (Cont.)

o 20:: N3 V mmm3m3 w moan:

 

 

    

3.....1 i o
N N
m
...... s A
M
.m
h
m. o o
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3.....» .1..V._.ri¥3tn.r3 I... if“?
m .. ,. I ... .. V. .... .V V. .. ...; V .. .23. ... yrs... m
5 .V . _ 6
5000 Aumo AWOO awmo mooo wwwo mmoo mwmo mooo

tease: _: 2583

Non d mmoamsg
o 20:: meg: o
I'll-III].

Depth in Meters

. . 1.31.: 52:? .5 V.. V.

I»: .155; ”V

 

bongo: _: 23an

Figure A43 Segments 3&4 of Zediker Road Profile 1.

101

Tuolumne and Merced River Fluvial Fan GPR Profiles

Bradbury Road Profile 1

Ema V . 9ch . .mm03w3 _

0

Depth in Meters

o No “8 do 88 :8
gang _3 25an

mamau V mmoBman N

o ..1. r . .111.

..mm& o

    

0‘
:

,QVV§VVVF..s V ,3..an
m 1.;233. .2114

Depth in Meters

                

  

“V fink TV. 1.1“».
.>; V? V . V V m m
38 38 88 $8
vomEo: _: 33m;

)2 .3...“ V..

 

mwmm

 

Figure A44 Segments 1&2 of Bradbury Road Profile 1.

102

Merced Road Merged Profiles 1-2

moan: V .imnnm TN mmoamaz V VV V 20::

       

- Vii?

V V‘ ”V;

Depth in Meters

vomaos _: 2.396

.528 TM mmoBmsn N
O i! . V V .. .VV

__ VVVVVVV

“A? 113»:

Depth in Meters

., ...fifl. V ..V .VV...VV. V. .V W V . V..V.VV ». ..viflj V.
... In H . .317... ......VV .. V V .3 .WV' V.. .V....V.. ..,VV V1 pV. V». .VVV«.. .uVV V.
.V.}.Vis. if“ . if flwVVVVV..V..VV~VV§Vr i VV ..«mflbflkfivcbflwgfiut

 
 

:5... V v... V. V. .7 V......V.Fa..:.z; , . .LSV: it u._V.VV..VVV;..V.V.

v8.20: _3 23an

-2.

Figure A45 Segments 1&2 of Merced Road Merged Profiles 1

103

Merced Road Merged Profiles 1-2 (Cont.)

Depth in Meters

#30

kmoo

.523 TM moani w

some
_uomEo: _: imam;

mooo

 

Figure A46 Segment 30f Merced Road Merged Profiles 1-2.

104

Palm Road Merged Profiles 1-2

Depth in Meters

Depth in Meters

20:: .. . . . . ._ 351$ mmoamaz

V. _. t;

VVV7.Vt.)f~
73¢.r.

o mo 80 do 88 5.8
vOmEo: _: 2533

3.3 Tn Manama" N moS: o

0;

 

88 33 #8 38 88
_uomio: _: 33m:

. moo

_umo

moS:

 

c

Figure A47 Segments 1&2 of Palm Road Merged Profiles 1-2.

105

Bloss Road Merged Profiles 1-3

Depth in Meters

gngryfixVVr; it:

IFLE? . , _ _ V V

0 MS us do 88 :8 $8 :8 88
vomaoa _... imam:

 

    

   

Depth in Meters

       
 

V. V V s! i: V V

irifzga. _ £11: VVV Vi
¥i§I.¥VVE; , V if; i! 3.3.11.3
a xwgnggiising..Eif VrV-IVir a

{Err FIE Eéggtkilct vEEtLiEF tllrtVS‘il
~80 -mo nmoo Numo wooo wwmo wmoo wwmo 5000

v8.20: _a 2.2m;

    

 

Figure A48 Segments 1&2 of Bloss Road Merged Profiles 1-3.

106

Bloss Road Merged Profiles 1-3 (Cont.)

Depth in Meters

20%. V -w mmoBmg w

 

VV,
4V

V V V.
{$3qu a. V

. V _V ..
_ A); gVVVVVVfiH15rf

.V....»V...

38 two 88
Vuomao: .3 322...

V _V . V
.82 V VyVV VVVVV V,_VV V .

 

Figure A49 Segment 3 of Bloss Road Merged Profiles 1-3.

107

American Avenue Profile 1

>133 V macaw...” V

     
 

 

 

  

a mom" <<mwn 0
~
V VVVVVVVV V
V.. ....VVVVVVVVV. V
M .V.... VVV V
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D 5......er . . V
m VIVV'VVIVVurr .1335...) 111:3..VVVIV’... 311313313: 9. .V....EVEE. m
(is? .....43195. .33... 1r£VEJVVVVVV .tVVakZVFVVQIiflJVaV1:45.311?» 1£VVVVV.V..VV.V.E
.0 .....VV V.....If..r. ..V. V. .11... .V.}?! writs. .V.... .V¢.£?V.r. V..... g....VVV.V.V..V.V§$«§§.¥£ I». V<VV§§§E .o
.. . 9,... .V. .3. .V....V ......V 2...... 731:3... V .
0 So So do 88 :8 $8 :8 .88
v3.20: .3 2.2m:
0 mm: . >3~anmm03m3~ V. 2mm" 0
M
m V.. V V. V.....VEVV #1; VV A
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:Vri%. V V.....) an V. :.
V.....VVVVV 2...... VVVVV V; VVV.V a
V..... VVVVVZVV .V. .V.. r. .V.. V..».VQVVEVVMVVVV .3... 2.22:!
38 88 38 $8 3.8 88

 
 

v8.20: .3 2.9m:

Figure A50 Segments 1&2 of American Avenue Profile 1.

108

American Avenue Profile 1 (Cont.)

Depth in Meters

>338 V $632.: w
mm." . Emma

       

N N
b V. . a. A.
V o
.....st
m ......k; .....V ...... .V.... .V.... 22.....3.VVVVV:VV.§VV1 m
Vfififimmwi M .. . V..
.0 a. V0
.58 Awwo .500

.3220: .: imam;

Figure A51 Segment 3 of American Avenue Profile 1.

109

Pepper Road Profile 1

Depth in Meters

0 3° 8° do 58 :mo :8 :mo 88
.6920: _3 2.32m

vane: $03.53 N

   

 

20:: 0

Depth in Meters

88 ~30 38 38 woos
vomEo: .3 2583

 

Figure A52 Segments 1&2 of Pepper Road Profile 1.

110

Sunny Acres Road Profile 1

mc33< A _m.m©3,m3 d mmn

  
 

Depth in Meters

_a
O

o N8 moo do 88 58 :8
p830: _: 2583

F igure A53 Sunny Acres Road Profile 1.

111

Newport Road Profile 1

Depth in Meters

Depth in Meters

.I'7I!r>*g:;L:&

umo moo

   
   

_? .1?3At:3§
, :{1 . .L

 
 

T

_. _ tittiieusweitt i x
w ._,

23:: d $939.: A

til-.3! cl c.

_

.3 .. 2;...j e.

n Yulnlaaui. . ,.J.l:quL (inter.

  

. r c. _ e , . , . ..
58 :8 :8
_uomEo: _: 33m:

2353 d mmmBmB N

gFfi

;

gag _3 gag

..

u.

. . V J
. . .
5.5.0.1. s

fig;

331...} t‘hagJflsafiufitaigsgglr w:
., ‘.:. .. . . ,.. (Wang, ...n

, . .1
it.
1......

 

Figure A54 Segments 1&2 of Newport Road Profile 1.

112

Newport Road Profile 1 (Cont.)

Depth in Meters

SJa1aw ul uomsod

Figure A55 Segment 3 of Newport Road Profile 1.

113

 

lunos0
s tuawfias L 1dM3N

uu0N

0

Sperry Road Profile 1

Depth in Meters

Depth in Meters

 

mum? . mmoamg d

.I III: 1! 1

411.111 I11

do .08 Ema

 

o mo 8° 58 :8 88
$830: _: 2583
0 Meg: mUmJL meBmanN 20:: o
all I II. 'I III. .1! . II: I . ul<

Nmoo

38 88 33
e850: _3 2583

  
 

Figure A56 Segments 1&2 of Sperry Road Profile 1.

114

Sperry Road Profile 1 (Cont.)

mos": mvméd mmoamg w

0;,
_Vr

, a , .; . we. . _ ..Jw.iex<{.c
, , , _ ll. .4

Depth in Meters

.
.
g V

  

r _V , r .
88 $8 $8 38 88
tonne: _: 2582..

moi: momQ . $032: A

c iii 1:14

Depth in Meters

. ,
3.13,. ... ...V .
_

.

88 $8 $8 ado 38
wouao: _: 2.2m;

mnmo

wmwo

203:

 

wmoo

      

Figure A57 Segments 3&4 of Sperry Road Profile 1.

115

Grayson Road Profile 1 (Graysl)

mm: 033 S $9.83 fl <<mMH.

. . . ,3‘ mg???
52?: . , Essafeé 33.. 331314211.

.... :2; L V : ,9; :4: g

i, .2. _.ifiiéii aezgiz},__._§§._§}szisi _.

Depth' In Meters

 

o N8 80 do 88 :8 GS 38 88
32:0: _: :38;

035 A meBmDH u

Depth in Meters

...: «1%.. 1.3;; _W 795;.

88 ~an #8 58 88 $8 $8 38
P330: .3 332m

 

 

Figure A58 Segments 1&2 of Grayson Road Profile 1 (Graysl).

116

Pioneer Road Profile 1

Depth in Meters

Depth in Meters

Numo

Roam a $933 d

88 S8
_uonzo: .3 2.396

203m A $9.32.; N

88 SS
womaoz _: Ema:

 

 

Figure A59 Segments 1&2 of Pioneer Road Profile 1.

117

Pioneer Road Profile 1 (Cont.)

Depth in Meters

   

4: o
8 m
0 O
c

H

3'
.U '.U.
of, O
m_._,, 3
:0 m
6' —-
3 16’
5 LC
:4, 3
mm (D
"O 3
(Do r-r
G w
2

0

£1 3
U1 . :-

° _. oo o A N o

c

Figure A60 Segment 3 of Pioneer Road Profile 1.

118

Redwood Road Profile 1

Depth in Meters

Depth in Meters

ogre

Nmo

mmaée d mmm3m3 d

58 53

_uonzo: .3 25an

mania d $9.53 N

 

$8 88
peace: _: 25.8;

52 o

 

Figure A61 Segments 1&2 of Redwood Road Profile 1.

119

Monte Vista Road Profile 1

Depth in Meters

Depth in Meters

_#§L..3_§tf

~08 -mo

...ii

a

2.038 . $032.: A

. , ...;
. _... g é?
.. ._ 3%.???3:. .Essir._:f’

3%"

£33.31:

.1132?!....... ,

jéiii. 3.313...
triflisifizgi xi.

3* {2125393 .gegegii

do 88 $8 $8
.93an _: 2583

2.038 . mm©3m3 N

 

_ _
“do 88 $8 $8
v8.20: _: _SmHmR

 

 

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Figure A62 Segments 1&2 of Monte Vista Road Profi

120

Monte Vista Road Profile 1 (Cont.)

Depth in Meters

Depth in Meters

<<mmH 2.0sz A mm©3m3 w 3%

.A .. ._ A. A A 4 .V. .I
h A A
A _, T A ..AA... A r

A _

35%.: ....rmafA

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111...... iii; ”Ari? iizi ...:
m zigzagiiiifiiifiia firiicfifri iii;
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a, 3i? V..}. 1.1....“ _..!S “r
x _,;.A:.$T..i.§: ,1?- .=.._?..;:L.§.;; .3; left? 8
88 $8 a8 38 88 $8 $8 $8 88
_uomEo: _: 2.2m;

    

2.03m . mmmBmzH A

o E m. 28H o

"Assiii..aém

w lerfieflrgg,

9.22.. ’52 23..
88 38

p850: _: _SmHma

 

Figure A63 Segments 3&4 of Monte Vista Road Profile 1.

121

Mitchell Road Profile 1

Depth in Meters

Depth in Meters

20:: 2:3: . wmmamsa . moS:

       

. _, . ...: , ,_ ,
3..“. d . ,_. 9.12....125142. , . . . .. . gr
0 2.3.3.115. s.§.._.:,£.rT:.. 3.../1.3:: gizggig . a
$1.:ii ,
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3.7.3! 5..... i... 1233;: .... ... .sifpimiité i
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3:125:11p’$.~2¥13%v&2wr ~ «‘6‘

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vomao: 3 2583

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88 88 #8 “do 38 $8 38 was 88
v8.20: _: 2.2mm

lel.

Figure A64 Segments 1&2 of Mitchell Road Profi

122

Mitchell Road Profile 1 (Cont.)

20:: 1 .. 3:2: meBmsfiw . .. mac?

       

      

 

    

    

     

   

    

     
    

. ..., ...: _.....
fiffg‘ffit Maggi.

2.3...“ .... , _

,._ .. {1%. is? . _ ,
g; siziulif ,

..x, 11.559.12.13“ wifigiiizgfyaa?3...};a:... m

...... 4.13.2... .....Lgsq.1,s_1¢atl~ 3.51213333 :1........-.,, 3.5.91.2 21.5.3173: _; _.. , (1:7... «1
.... 2:31.11: .15.. tzzfafimif y? :1,x_§¥.§§.§v§?. {91%,}:
7.2.5111.......fezisti 3.... .2». .53:;E., 5 5...: «1., .... “32:41:... 2..
88 38 $8 3.8 .88 $8 $8 $8 88
p830: _... 332m

     

Depth in Meters

      

         
     
     

   

 
 
 
    

 

20:: . 2:2: 1 $952: A moS: o

   

 

Depth in Meters

., 13%;? :1? m
22.5113...“ ...???xé .33

       

    

figs: ...... .2131??? 3.1

    

     

   

     

    

a gigii. ,3... ages: .33.
5.12.311! . 1.153.133.1411. 1.x... 5,... .. _.§.1.12..,£:7 z§§§1§.1.»§zwiaiif
oooo owmo amoo oumo woos wwmo Vmoo wumo mooo

v8.20: .3 25an

Figure A65 Segments 3&4 of Mitchell Road Profile 1.

123

Mitchell Road Profile 1 (Cont.)

Depth in Meters

mmoo

2:8: . mmmBmg m

«do 88
p850: _: 2.2mm.

 

Figure A66 Segment 5 of Mitchell Road Profile 1.

124

Grayson Road Profile 1 (Grsonl)

 

Depth in Meters

Depth in Meters

030: . mmmBmZ.

J:.‘ , I 4:...unt1
7:51.. .,, git»... _
....Isv....2l..t..?. . , .1 .. .. ... 5...... ,
.11.... 33:11. .ifiqlftiéfi: ..49a¥i L1;

.1.

1.3:. i531... 3345.33 .

o umo moo do .08 .30 38 :8 ~08

v3.20: .3 2.3m:

mac: . macaw—z N

 

88 53 $8 38 88 38 $8 $8 .88
“comic: _3 33m;

Figure A67 Segments 1&2 of Grayson Road Profile 1 (Grsonl).

125

Grayson Road Profile 1 (Grsonl) (Cont.)

Depth in Meters

mmmfl
o

0.13: . mmmBmZ w

38 38
p830: _: _Smnma

<<mMH

 

1e 1 (Grson 1 ).

Figure A68 Segment 3 of Grayson Road Profi

126

Appendix B

127

Kearney Orchard Site GPR Profiles
This section presents all of the GPR data collected at the Kearney Agricultural

Center (KAC). GPR profiles were collected using both 100 and 50 MHz antennas.

3““ =I-Ill
Y121
m. II-I-I
--—---

-._II

II-II“
Y61 ‘ '

Y41

X11 X31 X51 X81 X101 X121 X141

“999"“ o 510 20 30 4o

GPR 555:5 Meters

Profile

' Borehole Location

Figure Bl Kearney Agricultural Center orchard site GPR gn'd map. Geoprobe borehole locations
used to groundtruth the GPR data are also shown.

128

SOMHz Y-Direction Profiles

50y141 Depth Section

 

Depth in Meters

 

Depth in Meters

{m3w°memmrzmfimma

O 10 20 3O 4O 50 6O 70

Position in Meters

Figure BZ 50y141 depth section.

Figure BS 50y121 depth section.

129

 

 

 

50y1 11 Depth Section

 

 

 

  

b O
I I |
i

 

E

G.)

E 8 ‘

3E 12 :.«$ 1":‘ju‘i:. '.nif”! h

816 1WW
20

Position in Meters

50y91 Depth Section

 
  
 
 

 

0-
C
512
8'16
0

10 30 7o 80
Position in Meters

Figure B4 50y111 depth section.

Figure B5 50y91 depth section.

130

50y81 Depth Section

 

 

Depth in Meters

 

Position in Meters

50y61 Depth Section

    

Depth in Meters
8

O 1 0 20 30 40 50 60 7O 80
Position in Meters

Figure B6 50y81 depth section.

Figure B7 50y61 depth section.

131

50y41 Depth Section

 

U1

_.I
U1
.lt ‘

Depth in Meters
S

  

20 =

 

0 1 O 20 30 40 50 6O 70 80
Position in Meters

50MHz X-Direction Profiles

50x1 1 Depth Section

    

 

 

Depth E} Meters
O

_I

   

O 10 20 30 40 50 6O 70 80 90
Position in Meters

Figure B8 50y41 depth section.

Figure B9 50x11 depth section.

132

50x31 Depth Section

 

Depth in Meters

 

0 10 20 30 40 50 6O 70 80 90
Position in Meters

50x51 Depth Section

Depth in Meters

 

o) 10 20 30 4o 50 60 7080
Position in Meters

Figure B10 50x31 depth section.

Figure Bll 50x51 depth section.

133

1'2

EL... henna. E‘E‘E:E.EEE 0
0 4 8 2 6 0
9.30.2 E ..tQmQ

 

Swami). C. LHQGD

 

Figure B
Figure B”

50x81 Depth Section

 

M-
hflflm -M

h

fl%fitl?m1a,.avl\ " “my gnu»...

:Qi'vm- 7c "in!!! $1..va i“ .Mmmthfllw A M
:‘ r1». x‘eo’muunu'fer‘m

'\.*"‘j»« ~'.l'.’7|‘nn ,'_

«-

Depth in Meters

 

0 1O 20 30 4O 50 60 70 80
Position in Meters

50x101 erth Section

 

Depth in Meters

ONNCD-ho

 

Position in Meters

Figure B12 50x81 depth section.

Figure B13 50x101 depth section.

134

 

 

 

5i .1 _..‘h=-Ei1’n.grfig O
2 6 m

0 4 00 ..I .I
1.30822 2.. ..tQmQ

0 4 00 2 6 m

9.082). C_ LquO

FIEUYEBI
FighreBl

Depth in Meters

Depth in Meters

50x121 Depth Section

—-_—.__.’——~._ -..

 

 

 

,.1 - . 015-1

.m— New—‘11.,- "J‘
. » ,n ”aw.“ “an“. “wan-..-

- ht
l.~‘rw,-mWK“ “. ‘ u :H. . .-.4-...
. ' ~.‘ A 1 ' ‘.W .
.1_~;~~r:1'.-1-::_:;;~_3 " “ . . " ' ””1
- 111-, . ». {w -.. 9‘ ‘- 1. ,
" ‘a‘
1:81.19 ,. . ¢ .11. 4 ‘

"Jan—'- I“ Mr 1., ‘.fihznw»... r
'1’ I1~1~V‘§f’“ q .
3} 11‘de Whit." -147

I41

_ § . _

o 10 20 30 4'0 50 6O 70 80 90

Position in Meters

50x141 Depth Section

 

Y3

...‘5‘.“—--1W .1 npu'fic—us-fi-r- -~-~y:~——.

'- - ... v: v...
‘. 1... If ‘0- --‘ M9 - W-t—C ' h"- v ‘ f- ;n.-"‘
. '1- .

~ ‘*fiW-»<W~w-%me «can-am- ......

no

- I-.c...-...

I

’ 1’_;‘I‘_1>.': , F ,v 1.1

thinly-«1|

0 10 20 30 4O 50 60 70 80
Position in Meters

Figure 814 50x121 depth section.

Figure B15 50x141 depth section.

135

100MHz Y-Direction Profiles

y141 Depth Section

 

Depth in Meters
G o

N
O

 

0 1 0 20 30 40 50 60 70 80
Position in Meters

y121 Depth Section

 

Depth in Meters

 

o 1020 30 40 so 60 7o 80
Position in Meters

Figure 316 y141 depth section.

Figure 817 y121 depth section.

136

. e, 0
1:35.115
. 1 {Event
.1 i-~Efi 0 «IO
.V 1 5 1|- m
Ergo am: 2.. «IO
mew

S

Elia-nauti-
‘inEmLhEEWWJ m
HI 0 all
I. aw: oum§H_ 5de
m.—

 

F1 gure B
Figure B

y111 Depth Section

 

Depth in Meters

 

0 1O 20 30 4O 50 60 70 80
Position in Meters

y91 Depth Section

0

 

 

U1

Depth in Meters
o

20

 

0 10 20 30 4O 50 60 7O 80
Position in Meters

Figure 318 yl 11 depth section.

Figure 819 y91 depth section.

137

I EEAEEHE 0
5 0 5 0
2

0
mhwuws. C. Spawn.

 

SEE-fpmtuh_Hvsafismhfimfii. 0
0 5 0 5 m
3.3m: 2.. SuQmQ

F“gtlre 82‘

~

FE‘s’Ure B?‘

y81 Depth Section

Depth in Meters

 

O 10 20 30 40 50 6O 7O 80
Position in Meters

y61 Depth Section

 

Depth in Meters
5‘

0 1O 20 30 4O 50 6O 70 80
Position in Meters

Figure B20 y81 depth section.

Figure B21 y61 depth section.

138

  

EE- fi- - . FE1~ Eigdng. 0 SEE: h-u— En Err... $1.2 Linltmffimcrgi 0
0 5 AU 5 O 0 5 O 5 0
1' al 2 all. all 2
30qu E LuQmD 3.3.22 2.. rtQmQ

 

F‘E’Ure B:

y41 Depth Section

 

Depth in Meters

 

0 10 20 30 4O 50 60 70 80
Position in Meters

100MHz X-Direction Profiles

x11 Depth Section

Depth in Meters

 

010 20 30 4o 50 60 7o 80 90
Position in Meters

Figure B22 y41 depth section.

Figure 823 x11 depth section.

139

EEE-EEIEF§E¥E§ELE 0 B
2 u
0:

tn

0 1|. 1-
3.322 2.. suQmQ

giggiimgflEwtahfiutmkunfifiia 0
5 0
2

O

5 0
whim—2 C. LuQmD

 

Figure B

x31 Depth Section

.—|
oU'IO

_a
Ln

Depth in Meters

N
O

 

0 10 20 30 4O 50 6O 7O 80 90
Position in Meters

x51 Depth Section

U10

Depth in Meters
8

20

 

0 1 0 20 3O 4O 50 6O 70 80 90
Position in Meters

Figure B24 x31 depth section.

Figure 825 x51 depth section.

140

.I iiiii . . .

0 5 0 5
1'. dull.

”.0qu E LquO

 

 

...-Jaw” E.‘ O

O
2

2‘.

E5213.- :EP: Etna-um. h. 1. ......arun.hrth.r.1§1m 0 M B
5 WU. m w

H. U

u: .0;

Pi rd

0 5 0
3.3.32 2.. £quQ

\

x81 Depth Section

 

_..:
m

Death in Meters
8

N
O

 

O 1 O 20 30 4O 50 60 70 80 90
Position in Meters

x101 Depth Section

Depth in Meters

 

O 10 20 30 40 50 60 70 80 90
Position in Meters

Figure 826 x81 depth section.

Figure 827 x101 depth section.

141

. liql.|l

0

5 0 pf
mcwuwS. C. 9.2000

 

O
2

G

. ..1 .i. ... ...“..f . «Ming: 0

 

O 5

O

5
20qu E ..thQ

0
2

F1Sure 825

Figure 839

x121 Depth Section

 

Deoth in Meters

 

0 1O 20 30 40 50 60 70 8O 90
Position in Meters

x141 Death Section

    

Depth in Meters
S

0 1O 20 30 4O 50 60 70 80
Position in Meters

Figure 328 x121 depth section.

Figure B29 x141 depth section.

142

Appendix C

143

CMP Experiments

In order to develop depth scales for our GPR profiles, common-mid point
experiments (CMP’s) were conducted at various points across the upper KRF, TRF, and
MRF surfaces. Presented here are the results of the CMP experiments. First a table that
contains the calculated near-surface velocity for each CMP experiment along with the
location listed in decimal degrees is given below. Second, all CMP images are presented

along with a location map showing the location of each CMP.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CMP Name Calculated Near Location in Degrees,
Surface Velocity Decimal Minutes
DRCMPl (50 MHz) No Value Calculated N 36d 43.261 ’ W 119d 35.467’
HLCMPl (50 MHz) 0.16 m/ns N 36d 37.327’ W 119d 37.636’
HLCMP2 (100MHz) No Value Calculated N 36d 37.327’ W 119d 37.636’
LNCMPI (50 MHz) 0.14 m/ns N 36d 38.561’ W 119d 30.103’
LNCMP2 (50 MHz) 0.12 m/ns N 36d 38.951’ W 119d 40.829’
PLCMPl (100 MHz) 0.13 m/ns N 36d 36.752’ W 119d 35.631’
PLCWZQO MHz) 0.13 m/ns N 36d 36.752’ W 119d 35.631’
KRCMPI (50 MHz) No Value Calculated N 36d 35.450’ W 119d 30.179’
KRCMP2 (100 MHz) 0.14 m/ns N 36d 35.450’ W 119d 30.179’
DNCMP2 (50 MHz) 0.14 m/ns N 36d 35.406’ W 119d 33.760’
BLCMPI (50 MHz) 0.14 m/ns N 37d 24.301 ’ W 120d 45.537’
MHCMPl (50 MHz) No Value Calculated N 37d 31.437’ W 120d 56.366’
NPCMPl (50 MHz) 0.14 m/ns N 37d 28.020’ W 120d 42.139’
PMCMPl (50 MHz) No Value Calculated N 37d 26.859’ W 120d 45.980’
RWCMPl (50 MHz) 0.16 m/ns N 37d 34.383’ W 120d 53.208’

 

 

Table C 1 Table listing all CMP experiments by name as well as calculated near surface velocity
and location in Degrees Decimal Minutes.

144

A) B)

  
  

   

   
        

DRCMP1 Time Section HLCMP1 Time Section

a 0 ‘ s

C C

O 125 O

U U

OJ (1)

8 250 8

C C

‘2“ 375 g

.E 500 .5

<1) G)

.g 625 .g

l— l-
1 5 9 13 17 21 25 29 2 6 10 14 18 22 26 30
Antenna Seperation (m) Antenna Seperation (m)
HLCMP2 Time Section LNCMP1 Time Section

8 o ‘ 3 o

C C

8125 8 125

(D a)

8250 8 250

C C

2375 2 375

'E 500 -E 500

“e” “5’

._ ._ 25

I_625 '— 6
2 6 10 14 18 2 6 10 14 18 22 26 30
Antenna Seperation (m) Antenna Seperation (m)

Figure C1 A) Del Rey Road CMP B) Highland Road 1 CMP C) Highland Road 2 CMP
(100MHz) D) Lincoln Road I CMP

145

B)

   

   

PLCMP1 Time Section
8 8 °
C C
O O 125
U U
a a
o o 250
g E
Z Z 375
.E as 500
a) 0
.§ .§ 625
l— l—
2 6 10 14 18 22 26 30 2 6 10 14 18 22 26 30
Antenna Seperation (m) Antenna Seperation (m)
KRCMP1 Time Section
V) m
'0 '0
C C
O O
U U
a) Q)
V1 V)
o o
C C
M m
z z
-‘=' .s
Q) a:
§ .§
l— ~ I—
2 6 10 14 18 22 26 30 2 6 10 14 18 22 26 30

Antenna Seperation (m) Antenna Seperation (m)

Figure C2 A) Lincoln Road 2 CMP B) Parlier Road 1 CMP (100MHz) C) Parlier Road 2 CMP D)
Kearney Orchard Site 1 CMP

146

A) 13)

       

     

         

KRCMP2 Time Section DNCMP2 Time Section
V! V!
E 'g 0
8 8 125
§ 3
250
o
5 s
E Z 375
-— c
cu '— 500
.§ “5’
[— l: 625
2 6 10 14 18 22 26 30 2 6 10 14 18 22 26 30
Antenna Seperation (m) Antenna Seperation (m)
BLCMP1 Time Section MHCMP1Time Section
8 O \ ‘8 0
g ' 1, 21..., C
U125 8 125
<1) G)
8250 8 250
C C
2375 2 375
.E 500 .5
GE) GE) 500
._ 625 ._
i... l— 625
2 6 1O 14 18 22 26 30 2 6 10 14 18 22 25 30
Antenna Seperation (m) Antenna Seperation (m)

Figure C3 A) Kearney Orchard Site 2 CMP (100 MHz) B) Dinuba Road 2 CMP C) Bloss Road 1
CMP D) Mitchel Road 1 CMP

147

A) B)
NPCMP1 Time Section PMCMP1 Time Section

  
    

 

375

500

Time in Nanoseconds
Time in Nanoseconds

625

 

Antenna Seperation (m) Antenna Seperation (m)

C)
RWCMP1 Time Section

C

 

\h LA) N —l
O \1 U1 N
0 U1 0 U1

Time in Nanoseconds
0‘
N
U1

 

2 6101418222630
Antenna Seperation (m)

Figure C4 A) Newport Road 1 CMP B) Palm Road 1 CMP C) Redwood Road 1 CMP

I48

CMP Location Maps

DRCMP1

LNCMP2
LNCMP1

HLCMP1

KRCMP1
DNCMP2

 

 

 

 

Kilometers

Figure C5 KRF texture map and roads coverage highlighting the locations of CMP experiments.
For texture map key see Chapter Two.

149

 

0 3 6 12 18 24

Kilometers

Figure C6 TRF and MRF texture map and roads coverage highlighting the locations of CMP
experiments. For texture map key see Chapter Two.

150

Appendix D

151

GPR System Components
Sensors and Software Inc. pulseEKKO 100 GPR system
50 MHz and 100MHz center frequency antennae
Transmitting and receiving antenna modules
Fiber optic cables connected transmitting and receiving antennae to the main GPR
console.
GPR triggering/sound box
Sensors and Software Inc. Past Port (facilitates faster data acquisition)
GPR system was attached to Gateway Solo laptop computer (Pentium II) that
acted as recording/processing device.
GPR operating software installed on computer
A deep cycle marine trolling 12V battery was used to power both the laptop and
the GPR console during data acquisition.
Transmitting and receiving units were each powered by two 12V — 2.3AH
rechargeable camcorder type batteries.
A pulseEKKO 100/IV fiberglass antenna cart

Odometer trigger wheel which attaches to antenna cart

Steps to Setup GPR System
Build fiberglass antenna cart
Attach antenna cart to car

Attach antennae to antenna cart

152

0 Attach transmitting and receiving modules to antennae (transmitting in front,
receiving in back)

0 Attach odometer trigger to GPR antenna cart

0 Connect antennae modules and odometer trigger to GPR console using fiber optic
cables

0 Connect GPR console to Gateway Solo laptop computer with serial cable

0 Connect manual trigger/sound box to GPR console

0 Connect fast port to GPR console and laptop

0 Connect GPR and laptop computer to deep cycle 12V battery

0 Place 12V — 2.3AH batteries in transmitter and receiver and turn components on

0 Turn on laptop and GPR console

0 Start GPR software on laptop computer (note: computer and GPR system
performed best when computer was run in DOS mode rather then in the windows
environment)

0 Test system by finding time zero with test shot

0 Enter data which will define the GPR profile and mode of operation: Starting
latitude and longitude, line name (road name), antenna separation, operation mode
(reflection or CMP), number of stacks, time window, data output characteristics
(wiggle trace, color, etc.)

Common Problems

Skipper! Traces

A common problem we encountered while collecting our GPR data was skipped

traces. This typically occurred when our speed exceeded approximately 6 kilometers per

153

i

hour (4 mph). Traces were also skipped when the system trigger (odometer wheel) who
sway excessively due to uneven road conditions or wind gusts. To correct for this
common error in our data sets we used the processing software (WINEKKO Version 3)

to fill gaps.

Dos Mode vs. Windows Environment

Early on in the collection of our GPR data it was noted that when attempting to
use the “fast port” and operating the system software in the Windows environment
(Windows 98 running Sensors & Software pulseEKKO V 4.22) the system was very
prone to console errors that would force us to restart the system. This prevented the
collection of GPR profiles of substantial length. Eventually it was realized that the
software was much older then the operating system and ran smoother in a basic DOS
environment rather then the Windows environment. Therefore, running the GPR
operating software in the DOS environment allowed for the collection of long
uninterrupted GPR profiles without the frequent console errors encountered early on in

our data collection.

GPR Data Processing
Processing of the GPR data was intentionally limited due to the fact that
interpretation did not require it. Yet in some instances some filters were applied in an
attempt to enhance specific features. For instance, a background subtraction filter was at
times applied that acted to enhance areas of increased depth of penetration. This filter did
show these areas well, but in the end it was noted that the same interpretation could be

made without the addition of the filter. The only filter that was consistently applied was

154

made without the addition of the filter. The only filter that was consistently applied was
the “dewow” filter, which acted to remove any low frequency “wow” from the data
which may become superimposed on high frequency reflections.
GPR Data Analysis
Data analysis was done manually and consisted of looking at each GPR profile
and placing specific sections along the profile into specific categories. The categories
chosen for this interpretation are as follows:

1) Areas of significantly deep signal penetration (> then 9 m).

2) Areas of relatively deep signal penetration (> 5 m but < 9 m).

3) Areas of very shallow signal penetration, which signaled the presence of paleosol

(generally 5 m or less).

4) Questionable area due to excessive noise or unclear reflection characteristics.
Once all of the profiles had been categorized data base file was created for each GPR
profile, which contained the category codes and trace locations along each profile. Using
this database file, the interpreted profiles could then be imported into ArcMap and joined
with the corresponding profile line coverage and plotted on top of the digitized county

soil surveys thus allowing for the visualizations presented in Chapter Two.

155

Appendix E

156

MATLAB SCRIPTS

Point Define Auto Script

In order to allow for the comparison of our GPR profiles with digitized county soil
surveys we needed to create a way to digitize our GPR profiles trace by trace. What was
developed was a MATLAB script entitled PointDefineAuto that took the GPR readings
obtained in the field (start and end) and output a text file that contained an x,y location
for every trace along the GPR profile. With this file, point coverages could be established
in ARC GIS (Geographic Information System) for each GPR profile that would allow for

it to be correctly plotted in space on top of the digitized soil surveys.

PointDefineAuto:

%MATLAB script that takes an input file containing start/end GPS pts, the number of
traces and a line ID %and creates an output file for a GPR profile that contains (x,y)
locations along that line at a set interval.

%Written February 2003
%George L. Bennett V

format long g;

[lineid,start_east,start_north,end_east,end_north,tracesbetween,flag,tracesafterend]=
textread('input.txt’,'%s %f %f %f %f %d %d %d');

dybetween = (start_north - end_north); % Calculates the difference between start and
end northing

dxbetween = (start_east - end_east); % Calculates the difference between start and
end casting

northing_step = dybetween/tracesbetween; % Calculates the step interval
eastingflstep = dxbetween/tracesbetween; % Calculates the step interval

true_disbetween = tracesbetween * .5;

m =—_ «end_north - start_north)/(end_east - start_east));
b = end_north - (m "‘ end_east);

157

 

theta = atan(m);
opposite = ((sin(theta))*true_disbetween);
adjacent = ((cos(theta))*true.disbetween);

delnorth = (start_north - end_north);
calc_line_dis = abs(delnorth/sin(theta));
error = abs(calc_line_dis - true_disbetween);
out = [error,calc_line_dis,true_disbetween];
fid = fopen('input_err','w’);

fprintf(fid, '%6.2f %6.2f %6.2f,out);
fclose(fid);

tracebetween = (l :tracesbetween)‘;

for n = (1 :tracesbetween) % For loop that assigns a northing
for every trace

northingbetween(n) = start_north - (northing_step*n);
end
for n =(1:tracesbetween) % For loop that assigns an easting
for every trace

eastingbetween(n) = start_east - (easting_step*n);

end
northbetween = (northingbetween)';
eastbetween = (eastingbetween)';
finaloutbetween = [tracebetween,eastbetween,northbetween];
final = (finaloutbetween)';

fid = fopen('input','w’); % opens file and creates it if it does not
already exist

fprintf(fid, '%6.5f\t %6.5f\t %6.5f\n',final); % writes data to file

fclose(fid); % closes file

% Calculates points after last know end point if flag is equal to 1
if flag = 1
true_disafter = tracesafterend * .5;
dxadj=(cos(theta)*(.5));
dyopp=(sin(theta)*(.5));
dxafterend = dxadj;
dyafterend = dyopp;
adj acentend=(cos(theta)*(true_disafier»;
tracesafterend = (1 :tracesafterend)‘;
if end_east > start_east
eastingafter = (end_east+dxadj :dxadj :end_east+adj acentend);
else
east = (end_east-adjacentendzdxadj:end_east-dxadj);
eastingafter = fliplr(east);

158

end
y = (m * eastingafter) + b;
eastafier = (eastingafter)';
northafter = (y)';

finaloutafterend = [tracesafierend,eastafier,northafter];

finalafier = (finaloutafterend)';
fid = fopen('input2',’w');

% opens file and creates it if it does not already exist

fprintf(fid, '%6.5f\t %6.Sf\t %6.5f\n',finalafter); % writes data to file
fclose(fid); % closes file

else

end

159

 

GPRZ Script
In an attempt to automate the process of interpreting our GPR profiles a

MATLAB script was developed that attempted to pick the depth at which the GPR signal
in each trace went to noise. The script would then mark this depth in each GPR trace and
the values could then be connected to plot on top of the GPR profile showing locations of
increased depth of penetration relative to areas in which the GPR signal had been
attenuated. To do this a text file containing all of the numerical GPR data values was
extracted from TRANSFORM (GPR data display program). This data was then
normalized within MATLAB and a trace energy value was chosen that would correspond
to the value at which the signal had gone to noise. Once the depth to noise values had
been calculated the resulting information was smoothed using the loess (quadratic fit)
smoothing function and the data were plotted on top of the GPR profiles. (See Chapter 3)
GPR2:

%MATLAB script that normalizes and reads each trace in a GPR profile and attempts to

define the point at %which the GPR signal goes to noise. Script then takes the depth to
noise values and smoothes this data %and plots it on top of the GPR data for comparison.

%Written September 2003
%Phanikumar Mantha & George L. Bennett V

function gpr2

epsilon=0.30; °/o Sets cutoff noise cutoff value

load input.txt; % Text file that contains numerical GPR data
a=input;

depth=a(:,1); % Identifies and labels depth values in the numerical
GPR data.

i_neg=max(find(depth < 0));
[nrow,ncol]=size(a);

% Truncates the negative depth values at the top of the file -------

for j=1 :ncol
t€r1‘113=a(:,j);

160

 

temp(1 :i_neg,:)=";
aa(=.i)=temp;
end
a=aa;
depth=a( : , 1);
[nrow,ncol]=size(a);

for k = 2:ncol
dist(k)=(k-1 )*0.5;
end

ratio = max(dist)/max(depth);

% Normalizes GPR data
for i=2zncol
temp=a(:,i);
amax=max(temp);
amin=min(temp);
diffr-amax-amin;
a_norm(:,i) = (temp - amin)./diff;
end

a_norm( : , 1)=depth;

% Plots normalized GPR data
figure(2);

a_norm2=a_norm;
a_norm2(:,1)=";
h=imagesc(dist,depth,a_norm2);
colorbar;

hold on;

for j=2:ncol
signal=a_norm(:,j);
[ijk] = find_depth(signal,epsilon);
icrit(j )=ijk;

end

for j=22ncol
if(isnan(icrit(i)))
crit_depth(j) = nan;
else
crit_depth(j) = depth(icrit(i));
end
end

161

 

crit_depth( 1)=nan;

critd = flipud(crit_depth);

critd_smooth = smooth(dist,crit_depth,0.1,'loess');

cds = critd_smooth';

mat = [dist; cds]';

% save critd_smooth.txt cds -ASCII;

save critd_smooth.txt mat -ASCII; % Saves smoothed data into text file

plot(dist,critd_smooth,'w-','linewidth',3);

ccd = crit_depth';

cds = critd_smooth';

save crit_depth.txt -ASCII ccd; % Saves crit_depth values to text file

% Plots GPR data which will be background for smoothed data.
figure(3)

h=imagesc(dist,depth,a_norm2);

colorbar;

function [icrit] = find_depth(signal,epsilon)
nd=length(signal);

for i=40:nd
if (signal(i) < epsilon) icrit=i;
return
else
icrit=nan;
end
end

162

 

 

 

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163

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