DNS DUP BLD2023-1472+GEO REPORT+11.16.2023_1.59.46_PM+3905546PanGEG)C O R P O R A T E D
Geotechnical & Earthquake
Engineering Consultants
March 1, 2023
File No. 23-017
Robert Boyker
Avid Landscape Management LLC
7328 210th Street SW
Edmonds, WA 98026
Subject: Geotechnical Report
Geologic Hazards Evaluation
21019 74th Avenue West, Edmonds, Washington
Permit #BLD2022-0670
Dear Mr. Boyker,
As requested, PanGEO, Inc. completed a geotechnical study to evaluate the geologic
hazard areas mapped at the site for the proposed gravel parking. This study was
performed in general accordance with our mutually agreed scope of work outlined in our
proposal dated January 19, 2023. Our service scope included reviewing readily available
geologic and geotechnical data in the project vicinity, reviewing neighboring historical
parcel documentations and current design plans, excavating three test pits, conducting a
site reconnaissance, and developing the recommendations and conclusions presented in
this report.
SITE AND PROJECT DESCRIPTION
The subject site is a rectangular parcel approximately 0.17 acres in size located at 21019
74th Avenue West in Edmonds, Washington (see Vicinity Map, Figure 1). The subject
site is bordered to the west by 74th Avenue West, to the northwest by two single -story
buildings occupied by Avid Landscaping, to the northeast by an elevated asphalt parking
lot, and to the south and east by asphalt parking for the neighboring office park. The site
is currently occupied by a single -story residence with two sheds. Based on our field
3213 Eastlake Avenue East, Suite B
Seattle, WA 98102
Tel (206) 262-0370
www.pangeoinc.com
Geotechnical Report: Geologic Hazards Evaluation
21019 74th Avenue W, Edmonds, WA
March 1, 2023
observations and review of the topographic survey map, the site grade slopes down from
west to east with an average gradient of about 8 percent (see Plates 1 and 2, below).
Plate 1. View of the existing residence on the west Plate 2. Rear view of site. Looking southwest from
portion of the site, looking northeast from 74' Avenue adjacent elevated parking structure at northeast corner of
West. site.
An approximate 4-foot-tall rockery provides a grade -break with the asphalt parking to the
east of the site, becoming up to 12-foot-tall as the rockery wraps around to the southern
site boundary (see Plates 3 and 4, below).
Plate 3. Heavily vegetated, approximate 4-foot-tall Plate 4. Heavily vegetated, up to 12-foot-tall rockery
rockery along east site boundary. Looking southwest. along south site boundary. Looking northwest.
We understand you plan to change the land use of the site. The proposed project includes
demolishing the existing structures at the site and install a gravel parking. Based on the
City's review comments dated August 1, 2022, because ground disturbance is proposed
23-017 21019 74th Ave W Rpt 2 PanGEO, Inc.
Geotechnical Report: Geologic Hazards Evaluation
21019 74th Avenue W, Edmonds, WA
March 1, 2023
to occur within 50 feet of the steep slope near the southeast corner of the site, a
geotechnical report per ECDC 23.80.050 that addresses the criteria and standards in
ECDC 23.80.060 and 23.80.070 is required for permitting to address the mapped
geologic hazards at the site.
The conclusions and recommendations outlined in this report are based on our
understanding of the proposed improvements, which is in turn based on the project
information provided to us. If the above project description is substantially different
from your proposed improvements, or if the project scope changes, PanGEO should be
consulted to review the recommendations contained in this study and make
modifications, if needed.
SITE GEOLOGY AND SUBSURFACE CONDITIONS
SITE GEOLOGY
Based on our review of the Composite Geologic Map of Sno-King Area, Central Puget
Lowland, Washington (Booth, et al, 2004), the project site is underlain by Vashon
advance outwash (Map Unit: Qva). Vashon advance outwash (Qva) consists of sand and
gravel deposited by meltwater streams emerging from an advancing glacier. Advance
outwash has also been glacially overridden and as such is dense to very dense.
TEST PIT EXCAVATIONS
Subsurface exploration for this study included observing the excavation of three test pits
(TP-1 through TP-3) excavated by the client on January 25, 2023. The test pits were
excavated to a maximum depth of about 8 feet below existing grade. The approximate
locations of the test pits are indicated on the attached Figure 2, Site and Exploration Plan.
A geologist from PanGEO was present during the field exploration to observe the test pit
excavations, obtain representative samples, and to describe and document the soils
encountered in the explorations. The soils were logged in general accordance with the
system summarized on Figure A-1, Terms and Symbols for Boring and Test Pit Logs.
The summary test pit logs are included as Figures A-2 through A-4 in Appendix A, which
provides descriptions of the materials encountered, depths to soil contacts, and depths of
seepage or caving, if present, observed in the test pit sidewalls.
23-017 21019 74th Ave W Rpt 3 PanGEO, Inc.
Geotechnical Report: Geologic Hazards Evaluation
21019 74th Avenue W, Edmonds, WA
March 1, 2023
The relative in -situ density of cohesionless soils, or the relative consistency of fine-
grained soils, was estimated from the excavating difficulty, probing the sidewalls with a
1/2-inch diameter steel rod, and the stability of the test pit sidewalls. Where soil contacts
were gradual or undulating, the average depth of the contact was recorded in the logs.
SOIL CONDITIONS
In general, the soils encountered in the test pits consisted of about 3 to 4 feet of loose to
medium dense silty sand with debris (fill) overlying dense sand with gravel and cobble
that extended to a maximum depth of about 8 feet below ground surface, which we
interpret as the Vashon advance outwash mapped at the site. Detailed descriptions of the
subsurface conditions encountered at the test pit locations are included in Appendix A of
this report.
GROUNDWATER
Groundwater or seepage was not encountered within the excavation depths at the test pit
locations at the time of excavation. It should be noted that groundwater or seepage levels
will likely fluctuate depending on the season, amount of rainfall, surface water runoff,
tides, and other factors. Generally, the water level is higher and seepage rates are greater
in the wetter, winter months (typically October through May).
GEOLOGICALLY HAZARDOUS AREAS ASSESSMENT
Based on a review of the City of Edmonds GIS map and the Edmonds Community
Development Code (ECDC), the east and south boundaries of the subject site are mapped
within landslide and erosion hazard areas. The rockeries bounding the east and south
property lines is considered a steep slope (greater than 33% slope).
LANDSLIDE HAZARDS EVALUATION
Based on review of the topographic survey map provided to us and our field observations,
the site generally slopes down at a gentle grade from the west to east with an average
slope gradient of about 8 percent. However, the rockeries along the east and south
property lines, ranging from approximately 4 to 12 feet in height, appears to meet the
steep slope definition (33% or greater slopes) per Snohomish County map (see Plates 5
and 6, next page).
23-017 21019 74th Ave W Rpt 4 PanGEO, Inc.
Geotechnical Report: Geologic Hazards Evaluation
21019 74th Avenue W, Edmonds, WA
March 1, 2023
26'
0,:2
N
014 �
M �
n N
22 21019
1104 2
1 1 7315
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■
Plate 5. Landslide Hazard 40% (orange) and Erosion Plate 6. Steep Slope >33% (orange) as mapped by
Hazard 15%-40% (yellow) as mapped by City of Snohomish County (subject parcel in red)
Edmonds (subject parcel in red)
According to the ECDC 23.80.020 (B.4), "Any slope of 40 percent or steeper that
exceeds a vertical height of 10 feet over a 25 foot horizontal run. Except for rockeries
that have been engineered and approved by the engineer as having been built according
to the engineered design, ...... " Based on our site reconnaissance and LiDAR image
research (see discussion below), it is our opinion that steep slopes are the result of the
previous grading during site development for the adjacent asphalt parking areas. As such,
the existing rockeries can be exempted from the designated landslide hazard (see Plate 5,
below)
In addition, based on our test pits excavated at the site, dense outwash soil was
encountered behind the rockeries near the top of steep slope. It is also our opinion that the
risk for the potential future landslide is considered minimum.
LiDAR Image — We reviewed readily available aerial photography and LiDAR imagery
to assist in understanding previous grading that occurred within the site vicinity. It is our
understanding that the site rockeries were constructed as part of a grading permit to
remove approximately 10,200 cubic yards of material for construction of the asphalt
parking for the Edmonds Professional Center southeast of the site and under the Approval
of Variance V-23-90 dated December 21, 1990 (See Plates 7 thru 10, next page). The
23-017 21019 74th Ave w Rpt 5 PanGEO, Inc.
Geotechnical Report: Geologic Hazards Evaluation
21019 74th Avenue W, Edmonds, WA
March 1, 2023
LiDAR images also show no signs of landslide activities on the site and its immediate
vicinity.
Plate 7. Google Earth Imagery dated July 1990 prior to Plate 8. Google Earth Imagery dated June 2002 after
construction of rockeries and parking grading (subject construction of rockeries and grading procedures (subject
parcel in red) parcel in red)
Plate 9. LiDAR Imagery dated 2006 (TerraPoint USA, Plate 10. LiDAR Imagery dated 2017 (Quantum Spatial,
Inc., 2007) (subject parcel in red) 2017) (subject parcel in red)
23-017 21019 74th Ave W Rpt 6 PanGEO, Inc.
Geotechnical Report: Geologic Hazards Evaluation
21019 74th Avenue W, Edmonds, WA
March 1, 2023
Site Reconnaissance — A site reconnaissance of the subject property was also conducted
on January 16, 2023. During our site reconnaissance, although heavily vegetated, the
adjacent rockeries appear to be performing adequately. We did not observe obvious
evidence of past slope instability, ground movement, or soil migration from behind the
rockery at the subject site (see Plates 3 and 4, page 2). Based on our field observations
and the results of the explorations conducted at the subject site, in our opinion, the subject
site appears to be globally stable in its current configuration.
Furthermore, it is our opinion that the proposed ground disturbance (gravel parking)
within 50 feet of the steep slope (rockeries) as planned are feasible from a geotechnical
engineering standpoint. It is our further opinion that the proposed project as currently
planned will not adversely affect the overall stability of the site or adjacent properties.
EROSION HAZARDS EVALUATION
According to USDA Soil Conservation Service Map, the site soil is mapped as the
Alderwood-Urban land complex, 2 to 8 percent slopes at the northern approximate half of
the site while Alderwood-Urban land complex, 8 to 15 percent slopes are present at the
southern half of the site.
Based on the soils encountered in the test pits and site topography, the near -surface site
soils are anticipated to exhibit slight to moderate erosion potential. However, due to
minor ground disturbance and excavations planned, in our opinion, the potential erosion
hazards at the site can be effectively mitigated with the best management practice during
construction and with properly designed and implemented landscaping for permanent
erosion control. During construction, the temporary erosion hazard can be effectively
managed with an appropriate erosion and sediment control plan, including but not limited
to installing silt fence at the construction perimeter, limiting removal of vegetation to the
construction area, covering stockpile soil or cut slopes with plastic sheets, constructing a
temporary drainage pond to control surface runoff and sediment trap if needed, placing
rocks at the construction entrance, etc. Permanent erosion control measures should
include establishing vegetation, landscape plants, and hardscape established at the end of
proj ect.
23-017 21019 74th Ave w Rpt 7 PanGEO, Inc.
Geotechnical Report: Geologic Hazards Evaluation
21019 74th Avenue W, Edmonds, WA
March 1, 2023
23.80.060 DEVELOPMENT STANDARDS — GENERAL REQUIREMENTS
According to ECDC 23.80.060, alterations of geologically hazardous areas or associated
buffers may only occur for activities that:
l . Will not increase the threat of the geological hazard to adjacent properties beyond
predevelopment conditions;
2. Will not adversely impact other critical areas;
3. Are designed so that the hazard to the project is eliminated or mitigated to a level
equal to or less than predevelopment conditions; and
4. Are certified as safe as designed and under anticipated conditions by a qualified
engineer or geologist, licensed in the state of Washington.
Based on the site subsurface information and our understanding of the current plans, it is
our opinion that the proposed project meets the above conditions, and will not have
adverse impacts to the subject and surrounding properties during and after construction,
provided that project is constructed in accordance with the approved plans and commonly
accepted practice.
23.80.070 DEVELOPMENT STANDARDS — SPECIFIC HAZARDS
Portions of subject site are mapped as erosion hazard areas. However, based on the soil
conditions and proposed improvements, it is our opinion that setback and buffer distance
are not required for the currently proposed improvements. ECDC 23.80.070 states that
alterations of an erosion or landslide area hazard area, minimum building setback and/or
buffer may only occur for activities for which a hazards analysis is submitted and certifies
that:
a. The alteration will not increase surface water discharge or sedimentation to
adjacent properties beyond predevelopment conditions;
b. The alteration will not decrease slope stability on adjacent properties; and
c. Such alterations will not adversely impact other critical areas.
23-017 21019 74th Ave W Rpt 8 PanGEO, Inc.
Geotechnical Report: Geologic Hazards Evaluation
21019 74th Avenue W, Edmonds, WA
March 1, 2023
In our opinion, the proposed improvements as currently planned meet the above
conditions.
GEOLOGIC HAZARDS MITIGATIONS
Based on the results of our evaluation of the potential geologic hazards at the site, it is
our opinion that no specific mitigation, other than the erosion measure discussed above,
is required for the proposed improvements.
CONCLUSIONS
In summary, our test pits completed at the site encountered dense advance outwash soil at
shallow depths and a review of LiDAR image indicates no landslide activities within the
site vicinity. The adjacent rockeries appear to be performing adequately during our site
reconnaissance. Removing the existing shed from the top of the south rockery will reduce
the loading to the steep slope. It is our opinion that the proposed improvements may be
constructed as planned and would not compromise the slope stability.
CLOSURE
We have prepared this report for use by Avid Landscape Management LLC and the
project team. Recommendations contained in this report are based on a site
reconnaissance, a subsurface exploration program, review of pertinent subsurface
information, and our understanding of the project. The study was performed using a
mutually agreed -upon scope of work.
Variations in soil conditions may exist between the locations of the explorations and the
actual conditions underlying the site. The nature and extent of soil variations may not be
evident until construction occurs. If any soil conditions are encountered at the site that
are different from those described in this report, we should be notified immediately to
review the applicability of our recommendations. Additionally, we should also be
notified to review the applicability of our recommendations if there are any changes in
the project scope.
The scope of our work does not include services related to construction safety
precautions. Our recommendations are not intended to direct the contractors' methods,
techniques, sequences or procedures, except as specifically described in our report for
23-017 21019 74th Ave W Rpt 9 PanGEO, Inc.
Geotechnical Report: Geologic Hazards Evaluation
21019 74th Avenue W, Edmonds, WA
March 1, 2023
consideration in design. Additionally, the scope of our work specifically excludes the
assessment of environmental characteristics, particularly those involving hazardous
substances. We are not mold consultants nor are our recommendations to be interpreted
as being preventative of mold development. A mold specialist should be consulted for all
mold -related issues.
This report has been prepared for planning and design purposes for specific application to
the proposed project in accordance with the generally accepted standards of local practice
at the time this report was written. No warranty, express or implied, is made.
This report may be used only by the client and for the purposes stated, within a
reasonable time from its issuance. Land use, site conditions (both off and on -site), or
other factors including advances in our understanding of applied science, may change
over time and could materially affect our findings. Therefore, this report should not be
relied upon after 24 months from its issuance. PanGEO should be notified if the project
is delayed by more than 24 months from the date of this report so that we may review the
applicability of our conclusions considering the time lapse.
It is the client's responsibility to see that all parties to this project, including the designer,
contractor, subcontractors, etc., are made aware of this report in its entirety. The use of
information contained in this report for bidding purposes should be done at the
contractor's option and risk. Any party other than the client who wishes to use this report
shall notify PanGEO of such intended use and for permission to copy this report. Based
on the intended use of the report, PanGEO may require that additional work be performed
and that an updated report be reissued. Noncompliance with any of these requirements
will release PanGEO from any liability resulting from the use this report.
We appreciate the opportunity to be of service. Should you have any questions, please do
not hesitate to call.
Sincerely,
23-017 21019 74th Ave w Rpt 10 PanGEO, Inc.
Geotechnical Report: Geologic Hazards Evaluation
21019 74th Avenue W, Edmonds, WA
March 1, 2023
WAS
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SSI�NALti�G 0310112023
Spenser P. Scott, L.G. Chien -Lin (Johnny) Chen, P.E.
Project Geologist Senior Geotechnical Engineer
Enclosures:
Figure 1 Vicinity Map
Figure 2 Site and Exploration Plan
Appendix A
Summary Test Pit Logs
Figure A-1
Terms and Symbols for Boring and Test Pit Logs
Figure A-2
Log of Test Pit TP-1
Figure A-3
Log of Test Pit TP-2
Figure A-4
Log of Test Pit TP-3
23-017 21019 74th Ave W Rpt 11 PanGEO, hic.
Geotechnical Report: Geologic Hazards Evaluation
21019 74th Avenue W, Edmonds, WA
March 1, 2023
REFERENCES
Booth, D. B., Cox, B.F., Troost, K. A., and Shimel, S. A., 2004, The Composite Geologic
Map of Sno-King Area, Central Puget Lowland, Washington: scale 1:24, 000.
City of Edmonds, 2022, Edmonds Community Development Code Chapter 18.30.50,
18.30.60 and 18.30.70.
Google Earth Pro V 7.3.3.7786 (July 21, 2020). 47.808078,-122.332344. U.S.
Geological Survey; accessed February 21, 2023: http://www.earth.goo lg e.com
Quantum Spatial and USGS, 2017, Western Washington 3DEP LOAR Technical Data
Report; accessed February 21, 2023: https://IidgMortal.dnr.wa.gov/
Soil Survey Staff, Natural Resources Conservation Service, United States Department of
Agriculture. Web Soil Survey. accessed February 28, 2023:
bftp://websoilsurvey.nrcs.usda.gov
TerraPoint USA Inc and David Evans and Associates, Inc, 2007, Snohoco West 2006
LOAR Dataset; accessed February 21, 2023: https:Hlidarportal.dnr.wa.gov/
23-017 21019 74th Ave w Rpt 12 PanGEO, Inc.
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Legend: Base map modified from Topographic & Boundary Survey by Terrane, dated October 14, 2022
Approx. Test Pit Location
PanGEO, Inc., January 2023
Proposed Gravel Parking Approx. SOcale
PanGEO Geologic Hazards Evaluation
21019 74th Avenue West
I N C O R P 0 R A T E o Edmonds, Washington
SITE AND EXPLORATION PLAN
No. 23-017 I Figure No. 2
APPENDIX A
SUMMARY TEST PIT LOGS
RELATIVE DENSITY / CONSISTENCY
SAND / GRAVEL
SILT / CLAY
SPT
Approx. Relative
SPT Approx. Undrained Shear
DensityN-values
Density (%)
Consistency
N-values
Strength (psf)
Very Loose
<4
<15
Very Soft
<2
<250
Loose
4 to 10
15 - 35
Soft
2 to 4
250 - 500
Med. Dense
10 to 30
35 - 65
Med. Stiff
4 to 8
500.1000
Dense
30 to 50
65 - 85
Stiff
8 to 15
1000 - 2000
Very Dense
>50
85.100
Very Stiff
15 to 30
2000 - 4000
Hard
>30
>4000
UNIFIED SOIL CLASSIFICATION SYSTEM
MAJOR DIVISIONS
GROUP DESCRIPTIONS
•�'
GW:
Well -graded GRAVEL
Gravel
GRAVEL (<5% fines)
..
.....:
......................................................
50% or more of the coarse
o °
GP :
:
Poorly -graded GRAVEL
fraction retained on the #4
sieve. Use dual symbols leg.
o °
GM
......................................................
Silty GRAVEL
GP -GM) for 5% to 12% fines.
GRAVEL (>12% fines)
••••••••••••••••••••••••••••••
GC :
........................•••
Clayey GRAVEL
......................................................................
..........................................................
SW:
Well -graded SAND
Sand
SAND (<5 /° fines)
''
50% or more of the coarse
....................................:....>
%
SP
Poorly -graded raded SAND
y-g
fraction passing the #4 sieve.
Use duals leg. SP-SM �
;
":r"
............................................................
SM:
Silt SAND
y
%fin
for s%to12%fines.g
SAND (>1 2% fines)
, •••••••••••••••••••••••••••••••••••••••••••••••••••••••••
SC :
Clayey SAND
......................................................................
.............................................................
ML :
SILT
Liquid Limit < 50
............................................................
CL :
Lean CLAY
Silt and Clay
............................................................
OL :
Organic SILT or CLAY
==
—
50%or more passing #200 sieve
:..................................
:......................................................
MH :
Elastic SILT
Liquid Limit > 50
CH
Fat CLAY
OH
Organic SILT or CLAY
— ,
........................... ......................................
Highly Organic Soils
............................................................
PT :
PEAT
Notes: 1. Soil exploration to s contain material descriptions based on visual observation and field tests using a system
modified from the Uniform Soil Classification System (USCS). Where necessary laboratory tests have been
conducted (as noted in the "Other Tests" column), unit descriptions may include a classification. Please refer to the
discussions in the report text for a more complete description of the subsurface conditions.
2. The graphic symbols given above are not inclusive of all symbols that may appear on the borehole to s.
Other symbols may be used where field observations indicated mixed soil constituents or dual constituent materials.
DESCRIPTIONS OF SOIL STRUCTURES
Layered: Units of material distinguished by color and/or
Fissured: Breaks along defined planes
composition from material units above and below
Slickensided: Fracture planes that are polished or glossy
Laminated: Layers of soil typically 0.05 to 1 mm thick, max.1 cm
Blocky: Angular soil lumps that resist breakdown
Lens: Layer of soil that pinches out laterally
Disrupted: Soil that is broken and mixed
Interlayered: Alternating layers of differing soil material
Scattered: Less than one per foot
Pocket: Erratic, discontinuous deposit of limited extent
Numerous: More than one per foot
Homogeneous: Soil with uniform color and composition throughout
BCN: Angle between bedding plane and a plane
normal to core axis
COMPONENT DEFINITIONS
COMPONENT
SIZE / SIEVE RANGE
COMPONENT
SIZE / SIEVE RANGE
Boulder:
> 12 inches
Sand
Cobbles:
3 to 12 inches
Coarse Sand:
#4 to #10 sieve (4.5 to 2.0 mm)
Gravel
Medium Sand:
#10 to #40 sieve (2.0 to 0.42 mm)
Coarse Gravel:
3 to 3/4 inches
Fine Sand:
#40 to #200 sieve (0.42 to 0.074 mm)
Fine Gravel:
3/4 inches to #4 sieve
Silt
0.074 to 0.002 mm
Clay
<0.002 mm
TEST SYMBOLS
for In Situ and Laboratory Tests
listed
in "Other Tests" column.
ATT
AtterbergLimit Test
Comp
Compaction Tests
Con
Consolidation
DID
Dry Density
DS
Direct Shear
%F
Fines Content
GS
Grain Size
Perm
Permeability
PP
Pocket Penetrometer
R
R-value
SG
Specific Gravity
TV
Torvane
TXC
Triaxial Compression
UCC
Unconfined Compression
SYMBOLS
Sample/In Situ test types and intervals
2-inch OD Split Spoon, SPT
(140-lb. hammer, 30" drop)
H3.25-inch
OD Spilt Spoon
(300-lb hammer, 30" drop)
Non-standard penetration
test (see boring log for details)
Thin wall (Shelby) tube
Grab
Rock core
®
Vane Shear
MONITORING WELL
SZ
Groundwater Level at
time of drilling (ATD)
1
Static Groundwater Level
Cement / Concrete Seal
Bentonite grout / seal
Silica sand backfll
Slotted tip
Slough
Bottom of Boring
MOISTURE CONTENT
Dry
Dusty, dry to the touch
Moist
Damp but no visible water
Wet
Visible free water
GPmE® Terms and Symbols for
I IN C 0 R P 0 R A T E D Boring and Test Pit Logs Figure A-1
Phone: 206.262.0370
Test Pit Logs
Project No:
Project Name:
Project Location:
Excavated:
23-017
Geologic Hazards Evaluation
21019 74th Avenue West, Edmonds, WA
01/25/2023 by Avid Landscape w/ Kubota Small -Track Excavator
Test Pit No. TP-1
Location: 298422, 1272072 (Washington State Plane - North)
Approximate ground surface elevation: 402 feet (NAVD88)
Denth ft
Material Description
[Topsoil / Fill]
0-4
Approximately 24 inches of topsoil and duff above: loose to medium dense,
gray -brown, silty SAND, trace gravel and cobble, occasional roots and
rootlets, trash debris; non -plastic, moist
[Vashon Advance Outwash - Qva]
4-8
Dense, gray -brown to gray, poorly -graded SAND with gravel and cobble,
occasional roots and rootlets; non -plastic, moist
s
A. tom3
f ME
�d>`R� Yie-�{+� � -' F����T- i a•' axe
_
.may r �
1.
��_ti/ R � f~'.r:. ^�, •7�^ ,
Image of TP-1 approximately 8 feet below the existing ground surface. No groundwater was encountered
at time of exploration.
Logged by: S. Scott
PmGEE)
C O R P O R A T fi D
Ga twh,kal & Ea,Mp.aka Enp/ae d q Cons.Ift—
Figure A-2
Test Pit Logs
Project No:
Project Name:
Project Location:
Excavated:
23-017
Geologic Hazards Evaluation
21019 74th Avenue West, Edmonds, WA
01/25/2023 by Avid Landscape w/ Kubota Small -Track Excavator
Test Pit No. TP-2
Location: 298393, 1272071 (Washington State Plane - North)
Approximate ground surface elevation: 402 feet (NAVD88)
Depth ft
Material Description
[Topsoil / Fill]
0-3
Approximately 12 inches of topsoil above: medium dense, gray -brown, silty
SAND, trace gravel and cobble, abundant rootlets; occasional trash debris;
non -plastic, moist
[Vashon Advance Outwash - Qva]
3-8
Dense, gray -brown, poorly -graded SAND with gravel and cobble, trace
rootlets; non -plastic, moist
,i
�•-
a _ h -'' _
{N ' . tea,,; a�;� `` .. _ ?.
�:�� "ate.'•
. �'�'. ``y' .
Image of TP-2 approximately 8 feet below the existing ground surface. No groundwater was encountered
at time of exploration.
Logged by: S. Scott
PmGEOP O R A T E D
Ge (l h,ksl B EarMq— Engineering Co ... 1—ls
Figure A-3
Test Pit Logs
Project No:
Project Name:
Project Location:
Excavated:
23-017
Geologic Hazards Evaluation
21019 74th Avenue West, Edmonds, WA
01/25/2023 by Avid Landscape w/ Kubota Small -Track Excavator
Test Pit No. TP-3
Location: 298380, 1272030 (Washington State Plane - North)
Approximate ground surface elevation: 405 feet (NAVD88)
Depth ft
Material Description
[Topsoil / Fill]
0-3
Approximately 12 inches of topsoil above: medium dense, gray -brown, silty
SAND, trace gravel and cobble, trace rootlets; occasional trash debris; non -
plastic, moist
[Vashon Advance Outwash - Qva]
3-8
Dense, gray -brown to gray, poorly -graded SAND with gravel and cobble, trace
rootlets; non -plastic, moist
e� J ' f ♦ v l �C� 4 7
"
AN, � �
`��aq^
y / R. � .yam
.7 'T �. •+_5�('J. .��� .i _R -y �.i�
�`
-
Y 4.,►...
° �
i+III; t. "'�
•4'\. _� �
"l. �'
y, ,LA • �£ l
Jr
� .1• ��� s ice
Image of TP-3 approximately 8 feet below the existing ground surface. No groundwater was encountered
at time of exploration.
Logged by: S. Scott
PanGEOO R P O R A T E D
Ge (t h,ks1 B E, Mqo Engine g Co...1—ls
Figure A-4