BLD2024-0804+Geotechnical_Report+Infiltration Tests.6.14.2024_2.03.13_PM+4324101BLD2024-0804 RECEIVED
6/18/24
CITY OF EDMONDS
DEVELOPMENT
SERVICES DEPARTMENT
PanGE(9P O R A T E D
Geotechnical & Earthquake
Engineering Consultants
June 23, 2022
Project No. 22-237
HBRE Investments
Attn: Augustus Bukowski
1951 3rd Avenue West
Seattle, WA 98119
Subject: Infiltration Testing Report
Proposed Townhomes
310 Daley Street, Edmonds, Washington
Dear Mr. Bukowski:
As requested, PanGEO, Inc. completed an infiltration assessment of the site soils to assist the
project team with the drainage design at the above referenced property. Our service consisted of
excavating two test pits, performing two Small Pilot Infiltration Tests (PITS), and preparing this
summary report. In summary, the two small pilot infiltration tests completed at the site at depths
of about 5 feet and 4'/2 feet yielded steady-state infiltration rates of approximately 0.00 and 0.13
inches per hour, respectively.
We appreciate the opportunity to be of service. Please call if you have any questions.
Sincerely,
Michael H. Xue, P.E.
Principal Geotechnical Engineer
3213 Eastlake Avenue E, Ste B
Seattle, WA 98102
Tel (206) 262-0370
www.pangeoinc.com
TABLE OF CONTENTS
1.0 INTRODUCTION................................................................................................................... 1
2.0 SITE AND PROJECT DESCRIPTION............................................................................... 1
3.0 SUBSURFACE EXPLORATIONS....................................................................................... 1
4.0 SITE GEOLOGY AND SUBSURFACE CONDITIONS
..... 2
4.1 SITE GEOLOGY....................................................................................................................... 2
4.2 SOIL CONDITIONS................................................................................................................... 3
4.3 GROUNDWATER..................................................................................................................... 4
5.0 INFILTRATION TESTING AND RECOMMENDATIONS
..... 4
5.1 TEST METHOD........................................................................................................................ 4
5.2 CORRECTION FACTORS.......................................................................................................... 5
5.3 LONG TERM INFILTRATION RATE FOR DESIGN....................................................................... 5
5.4 CONSTRUCTION CONSIDERATIONS......................................................................................... 6
6.0 LIMITATIONS....................................................................................................................... 7
7.0 LIST OF REFERENCES....................................................................................................... 9
LIST OF ATTACHMENTS
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 PIT- I
Figure A-3 Log of Test Pit PIT-2
22-237 310 Daley St, Edmonds -Infiltration Rpt.doc i PanGEO, Inc.
INFILTRATION TESTING REPORT
310 - DALEY STREET
I+ DMONDS, WASHINGTON
1.0 INTRODUCTION
As requested, PanGEO, Inc. completed an infiltration assessment and testing of the site soils to
assist the project team with the drainage design at the above referenced property. Our service
consisted of excavating two test pits, performing two Small Pilot Infiltration Tests (PITS), and
preparing this summary report. The intent of our work is to evaluate the infiltration feasibility of
the site soils and to provide a design infiltration rate, if feasible, for the design of the proposed
infiltration system to be constructed at the site.
2.0 SITE AND PROJECT DESCRIPTION
The project site consists of an approximate 0.17-acre parcel in downtown Edmonds, Washington
(see Figure 1, Vicinity Map). The site is currently occupied by a single -story house in the west
half of the parcel (304 Daley Street), and a single -story duplex with a detached garage in the east
half of the parcel (312 and 316 Daley Street). The site is bordered by 3rd Avenue North to the
west, Daley Street to the north, single-family residences to the south, and a private alley to the
east. The grade gently slopes down from about Elevation 54.5 feet in the east end of the site, to
about Elevation 52.5 feet in the west end.
We understand that you plan to remove the existing building at 312/316 Daley Street and
construct a new 4-unit townhome building. We also understand that you plan to convert the
exiting building at 304 Daley Street into an office building under a separate permit. Based on
review of the preliminary plans, the proposed townhome building will be a 3-story, wood -frame
structure. We predict that site grading for the proposed project will include cuts and fill up to
about 4 feet for the foundation construction.
We understand it is planned to infiltrate surface water from the proposed improvements into the
site soils, if feasible. The approximate layout of the site is shown on the attached Figure 2, Site
and Exploration Plan.
3.0 SUBSURFACE EXPLORATIONS
Two test pits (PIT-1 and PIT-2) were excavated at the project site on May 26, 2022. PIT-1 was
excavated to about 5 feet below the existing ground surface for infiltration. PIT-2 was initially
22-237 310 Daley St, Edmonds -Infiltration Rpt.doc l PanGEO, Inc.
Infiltration Assessment
Proposed Townhomes: 310 — Daley Street, Edmonds, Washington
June 23, 2022
excavated to about 41/2 feet for infiltration testing and was then excavated to at about 8 feet deep
after the test to look for groundwater mounding or seepage. The approximate test pit locations
are shown on the attached Figure 2.
The relative in -situ density of cohesionless soils, or the relative consistency of fine-grained soils,
was estimated from the excavating action of the excavator, probing the sidewalls with a %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 log. After the infiltration test
was completed, the excavations were backfilled with the excavated soils and the surface was
tamped and re -graded smooth.
A geologist from our firm was present throughout the boring and infiltration test program to
observe the explorations, assist in sampling, and to document the soil samples obtained from the
explorations and perform the tests. The summary boring and test pit logs are included in
Appendix A.
4.0 SITE GEOLOGY AND SUBSURFACE CONDITIONS
4.1 SITE GEOLOGY
Based on our review of the Geologic Map of the Edmonds East and Part of the Edmonds West
Quadrangles, Washington (Minard, 1983), and the Composite Geologic Map of the Sno-King
Area (Booth et al, 2004) the site is underlain by Pre -Fraser deposits (geologic map unit Qpf) with
Whidbey Formation (Qw) mapped to the southwest of the site.
Pre -Fraser deposits are typically massive to laminated silts and clays with variable oxidation and
bedded sands and gravels. This unit is diamict in parts and typically dense to hard. Pre -Fraser
deposits generally exhibit a low infiltration capacity.
The Whidbey Formation generally consists of bedded, commonly oxidized, medium -to -coarse -
grained sand, and are typically dense to very dense. This unit is similar to the younger Vashon
Advance Outwash deposits but is characterized by its stratigraphic position and generally
heterogenous grain size. The Whidbey Formation generally has moderate infiltration capability.
22-237 310 Daley St, Edmonds -Infiltration Rpt.doc 2 PanGEO, hic.
Infiltration Assessment
Proposed Townhomes: 310 — Daley Street, Edmonds, Washington
June 23, 2022
4.2 SOIL CONDITIONS
For a detailed description of the subsurface conditions encountered at each exploration location,
please refer to our summary exploration logs provided in Appendix A. The stratigraphic contacts
indicated on the logs represent the approximate depth to boundaries between soil units. Actual
transitions between soil units may be more gradual or occur at different elevations. The
descriptions of groundwater conditions and depths are likewise approximate. The following is a
generalized description of the soils encountered in the test pits.
UNIT 1: Topsoil / Fill
Both test pits encountered approximately 2 to 3 feet of fill below surface vegetation. The fill
encountered in the test pits generally consisted of loose, silty, poorly graded sand with some
gravel and organic material.
UNIT 2: Pre -Fraser Deposits - Qpf
Directly below the fill in PIT-1, we observed dense to very dense, moderately cemented,
silty sand with gravel. The upper 2 feet of this unit showed indications of weathering,
including iron oxide staining, a disturbed appearance, and was less dense. We interpreted
this unit as the Pre -Fraser Possession Drift deposits mapped near the area based on its
similarities with glacial till and its proximity to the Whidbey Formation deposits observed in
PIT-2. This unit was only observed in PIT-1 and extended to the maximum exploration
depth of 5 feet.
UNIT 3: Whidbey Formation — Qw
Directly below the fill in PIT-2, we observed medium dense to dense, medium -grained sand
with trace silt and gravel. We interpreted this unit as the mapped Pre -Fraser Whidbey
Formation deposits within the project vicinity based on its heterogenous grain size and
oxidized appearance. This unit was only observed in PIT-2, and extended to the maximum
exploration depth of 8 feet.
Our subsurface descriptions are based on the conditions encountered at the time of our
exploration. Soil conditions between our exploration locations may vary from those encountered.
The nature and extent of variations between our exploratory locations may not become evident
until construction. If variations do appear, PanGEO should be requested to reevaluate the
recommendations in this report and to modify or verify them in writing prior to proceeding with
earthwork and construction.
22-237 310 Daley St, Edmonds -Infiltration Rpt.doc 3 PanGEO, Iric.
Infiltration Assessment
Proposed Townhomes: 310 — Daley Street, Edmonds, Washington
June 23, 2022
4.3 GROUNDWATER
Groundwater or seepage was not observed in PIT-1 at the time of our exploration. However, we
observed minor groundwater seepage at the bottom of PIT-2 at about 71/4 feet below grade,
following the infiltration testing procedure.
It should be noted that groundwater levels will 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).
5.0 INFILTRATION TESTING AND RECOMMENDATIONS
Two field infiltration tests, PIT-1 and PIT-2 were performed at the project site on May 26, 2022.
The test locations are indicated on the attached Figure 2. The test method and the results are
discussed below.
5.1 TEST METHOD
The field infiltration tests were conducted in general accordance with the procedure for Small -
Scale Pilot Infiltration Test (PIT) as outlined in section B.3.2 of the June 2017 — Edmonds
Stormwater Addendum. In general, the test consisted of the following procedure:
• A test pit was excavated to the approximate design bottom of the proposed infiltration
facilities with a minimum bottom area of 12 square feet.
• The test pit was pre-soaked by maintaining a water level of at least 12 inches above the
bottom of the pit.
• At the end of pre-soak period, a flow meter was used to monitor the amount of water
needed to maintain a constant head of 12 inches for at least one hour and until at least a
point at which a constant volume of water per time unit was achieved.
• At the end of the constant head test, we measured the falling head infiltration rate by
shutting off the water flow and recording the drop in water level over regular time
intervals for one hour or until all of the water was infiltrated.
The field infiltration rate was then calculated based on the final measured volume per time unit,
and the surface area of the hole. Based on the site conditions, test equipment and method, and
test results, we selected a constant head rate of 0.0 inches per hour and 0.13 inches per hour as
the field infiltration rate for PIT-1 and PIT-2, respectively. The results of our test are
summarized in Table 1, below.
22-237 310 Daley St, Edmonds - Infiltration Rpt.doc 4 PanGEO, Iric.
Infiltration Assessment
Proposed Townhomes: 310 — Daley Street, Edmonds, Washington
June 23, 2022
5.2 CORRECTION FACTORS
The infiltration rates calculated based on field measurements are considered short-term rates and
should be reduced through correction factors for design. The corrections factors account for site
variability, test method, and number of locations tested, degree of long-term maintenance, and
degree of influent control to prevent siltation and bio-buildup. The correction factors are outlined
in Appendix B.2 of the June 2017 — Edmonds Stormwater Addendum, and are summarized and
discussed below:
• Site Variability (CF,) — A range of 0.33 to 1.0 is provided in the Edmonds Stormwater
Addendum. Based on the test pits excavated across the project site, the soil conditions at
the site vary slightly at the proposed infiltration depth. However, within the footprint of
the proposed infiltration facility, the soils remained consistent. In our opinion, a CFI of
1.0 is appropriate for this site.
• Test Method (CFt) — For small scale infiltration tests, we assume CFt = 0.5.
• Degree of influent control to prevent siltation and bio-buildup (CFm) — Assuming a
good degree of control, we assume CFm of 0.9.
The Total Correction Factor (CFT) is then calculated as: CFT = CFI x CFt x CFm = 0.45.
5.3 LONG TERM INFILTRATION RATE FOR DESIGN
With the Total Correction Factor (CFT) of 0.45, the long-term design rate can be calculated from
the field measured rates. Table 1, below, details the infiltration data collected and the long-term
design rates calculated for each location.
During installation of the infiltration facility, the soil conditions at bottom of the excavation shall
be verified by a qualified professional, to verify that the excavation is sufficiently to
penetrate into the sand unit of the
Formation as observed in test nit PIT-2.
22-237 310 Daley St, Edmonds -Infiltration Rpt.doc 5 PanGEO, hlc.
Infiltration Assessment
Proposed Townhomes: 310 — Daley Street, Edmonds, Washington
June 23, 2022
TABLE 1: Small Pilot Infiltration Test Data Corrected for Long Term Design Rate
Field
Pre -Soak
Long Term
Test
Test
Test
Measured
Correction
Duration
Design Rate
Location
Stage
Duration
Rate
Factor
(hrs)
(in/hr)
(in/hr)
PIT-1 at 5
6
Constant
1 hour
0
0.45
0.0
feet
Head
PIT-2 at 4.5
6
Constant
1 hour
0.13
0.45
0.06
feet
Head
5.4 CONSTRUCTION CONSIDERATIONS
Infiltration facilities are post -construction facilities which are designed to improve the quality
and manage the volume of stormwater runoff by encouraging natural infiltration on -site. In
order to protect the infiltration receptor soils from becoming clogged with sediment and/or
becoming compacted during construction, we recommend the following measures be
implemented during construction:
• The infiltration facilities should be constructed as late in the schedule as feasible and
should not be constructed until after the upstream areas are stabilized.
• Heavy equipment traffic on prepared subgrades should be limited, especially during wet
weather.
• If fine grained sediment is deposited or tracked onto the infiltration system subgrade, it
should be removed using an excavator with a grade plate, a small dozer or a vacuum
truck.
• The subgrade should be scarified prior to placing fill to prevent sealing of the receptor
soils.
• Structural fill and aggregate base materials should be end -dumped at the edge of the fill
area and the material pushed out over the subgrade.
22-237 310 Daley St, Edmonds -Infiltration Rpt.doc 6 PanGEO, Inc.
Infiltration Assessment
Proposed Townhomes: 310 — Daley Street, Edmonds, Washington
June 23, 2022
• Grading of the infiltration galleries should be accomplished using low -impact earth -
moving equipment to prevent compaction of the underlying soils. Wide tracked vehicles
such as excavator, small dozers and bobcats are suggested.
• The infiltration system subgrade soils should be reviewed after excavation to verify the
soils encountered are as anticipated.
Test Pit Backfill. It should be noted that the backfill in the test pit locations was not
compacted to a dense condition or the requirements of structural fill. As such, during
construction of the project, the earthwork contractor should locate the test pits, remove the
loose backfill and replace it with properly compacted structural fill, if they are located with
the structural loading areas.
6.0 LIMITATIONS
We have prepared this report for Augustus Bukowski and the project design 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 consideration in design.
Additionally, the scope of our work specifically excludes the assessment of environmental
characteristics, particularly those involving hazardous substances.
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.
22-237 310 Daley St, Edmonds -Infiltration Rpt.doc 7 PanGEO, Iric.
Infiltration Assessment
Proposed Townhomes: 310 — Daley Street, Edmonds, Washington
June 23, 2022
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.
Sincerely,
of wash\
f
<; 21034819
N��sed Ge
osepapcevidfi7
Joe Dapcevich, L.G.
Staff Geologist
6A"leae?
Michael H. Xue, P.E.
Principal Geotechnical Engineer
22-237 310 Daley St, Edmonds -Infiltration Rpt.doc 8 PanGEO, hic.
Infiltration Assessment
Proposed Townhomes: 310 — Daley Street, Edmonds, Washington
June 23, 2022
7.0 LIST OF 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.
Minard, J.P., 1983, Geologic Map of the Edmonds East and Part of the Edmonds West
Quadrangles, Washington: United States Geological Survey, scale 1:24000.
City of Edmonds, 2017, Appendix B, Edmonds Stormwater Addendum.
22-237 310 Daley St, Edmonds -Infiltration Rpt.doc 9 PanGEO, Iric.
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I N C D R P D R AT ED Edmonds, Washington
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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)
''
•••••I......................................................
50% or more of the coarse
GP :
Poorly -graded GRAVEL
fraction retained on the #4
sieve. Use dual symbols (eg.
.............................
o °
.....:......................................................
GM
Silty GRAVEL
GP -GM) for 5% to 12% fines.
o
GRAVEL(>12/ofines)
••••••••••••••••••••••••••••••
GC :
........................•••
Clayey GRAVEL
......................................................................
..........................................................
SW:
Well -graded SAND
""
Sand
SAND (<5/o fines)
50% or more of the coarse
SP
Poorly -graded SAND
fraction passing the 94 sieve.
Use dual symbols SP-SM)
•• ••� �•
;; ;
SM :
Silty SAND
for 5%to12%fines.
o
•SAND(>12/o fines)
•••••••••••••••••••••••••••••••••••••••••••••••••••••••••
SC :
Clayey SAND
•• ...............................••
.............................
............................................................
MIL :
:
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
_ ,
HighlyOrganic 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 logs.
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
Atterberg Limit 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)
B3.25-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 backfill
Slotted tip
Slough
Bottom of Boring
MOISTURE CONTENT
Dry
Dusty, dry to the touch
Moist
Damp but no visible water
Wet
Visible free water
PanGEO Terms and Symbols for
I N C O R P O 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:
22-237
Proposed Residential Development
310 Daley Street, Edmonds, WA
5/26/2022 by Hilltop Excavation
Test Pit No. PIT-1
Location: 47.81362,-122.37759 (WGS84)
Approximate ground surface elevation: 52.5 feet (Topographic Survey)
Depth ft
Material Description
Loose, dark brown, silty, fine SAND with trace gravel, moist; numerous roots
0-2
and organics [Topsoil / Fill]
Medium dense to dense, brown -gray, slightly silty, f-m SAND with trace gravel,
2 — 41/2 moist; minor iron oxide staining [Weathered Pre -Fraser Deposits]
........................................................................................................................................................................................................................................................
Very dense, gray -blue, silty, f-m SAND with some f-m gravel, moist; moderately
41/2 — 5 cemented [Pre -Fraser Deposits - Qpf]
fvt
Yf
Image of PIT-1 at approximately 5 feet below the existing ground surface (testing depth). Groundwater
seepage was not observed during excavation.
Logged by: J. Dapcevich
PmGEO
I N C O R P O R A T E D
Geotechnlcal 8 Earthquake Eng/nearing Consultants
Figure A-2
Test Pit Logs
Project No:
Project Name:
Project Location:
Excavated:
22-237
Proposed Residential Development
310 Daley Street, Edmonds, WA
5/26/2022 by Hilltop Excavation
Test Pit No. PIT-2
Location: 47.81364,-122.37709 (WGS84)
Approximate ground surface elevation: 54.5 feet (Topographic Survey)
Depth ft
Material Description
0 — 3'/z
Loose, dark brown, silty, fine SAND with trace gravel, moist; numerous tree
roots and organics [Topsoil / Fill]
Medium dense to dense, brown -gray, medium SAND with trace silt and
gravel, moist; iron oxide staining [Whidbey Formation - Qw]
3'/z — 8
- Becomes very moist at 4 feet, and gray -blue at 41/2 feet
- Occasional lenses of m-c sand from 6 to 8 feet
t
1
t
;r
Image of PIT-2 at approximately 4%2 feet below the existing ground surface (testing depth). PIT-2 was
excavated to approximately 8 feet below grade following the infiltration test. Minor groundwater seepage
was observed at about 73/4 feet below grade.
Logged by: J. Dapcevich
PmGEI@
I N C O R P O R A T E D
Geotechnlcal 8 Earthquake Eng/nearing Consultants
Figure A-3