HomeMy WebLinkAboutRenton Highlands Landfill Site Investigation Report
Renton Highlands Landfill
(Undeveloped Parcel)
2880—NE 3rd Street
Renton, Washington
Prepared for: Mr. Richard Gilroy
Northward
1560— 140`h Avenue NE, Suite 100
Bellevue, Washington 98005
Prepared by: Kleinfelder Inc.
2405 - 140th Avenue, NE
Suite A101
Bellevue, WA 98005
(DECEIVED
Phone: (425) 562-4200 JUL 10 2001
Fax: (425) 562-4201
CITY OF RENTON
UTILITY SYSTEMS
July 25, 2000
Copyright 2000 Kleinfelder, Inc.
All Rights Reserved
This document was prepared for use only by the client,only for the purposes stated,and within a reasonable time from issuance.Non-
commercial, educational and scientific use of this report by regulatory agencies is regarded as a "fair use" and not a violation of
copyright.Regulatory agencies may make additional copies of this document for internal use.Copies may also be made available to the
public as required by law.The reprint must acknowledge the copyright and indicate that permission to reprint has been received.
Prepared for:
Mr. Richard Gilroy
Northward
1560— 140th Avenue NE, Suite 100
Bellevue, Washington 98005
Site Investigation Report
Renton Highlands Landfill
(Undeveloped Parcel)
2880—Northeast 3rd Street
Renton, Washington
Prepared by:
Anastasia Speransky
Staff Geologist
Scott D. Dwyer, PhD, DABT
Senior Project Manager
KLEINFELDER,INC.
2405— 140th Ave NE,
Suite A101
Bellevue, WA 98005
Phone: (425) 562-4200
Fax: (425) 562-4201
July 25, 2000
Copyright 2000 Kleinfelder, Inc.
All Rights Reserved
This document was prepared for use only by the client,only for the purposes stated,and within a reasonable time from issuance.Non-
commercial, educational and scientific use of this report by regulatory agencies is regarded as a "fair use" and not a violation of
copyright.Regulatory agencies may make additional copies of this document for internal use.Copies may also be made available to the
public as required by law.The reprint must acknowledge the copyright and indicate that permission to reprint has been received.
TABLE OF CONTENTS
1.0 PROJECT BACKGROUND AND SITE DESCRIPTION...........................................1
2.0 LOCATION.......................................................................................................................1
3.0 TOPOGRAPHY AND GEOLOGY.................................................................................1
4.0 RELEASE INFORMATION AND SITE CHARACTERIZATION............................1
5.0 GROUNDWATER INVESTIGATION..........................................................................2
6.0 PREVIOUS INVESTIGATIONS....................................................................................3
7.0 SELECTION OF CLEANUP STANDARDS AND REMEDIAL ACTION................4
8.0 SELECTION AND IMPLEMENTATION OF CLEANUP ACTION.........................4
9.0 CONFIRMATION SAMPLING......................................................................................4
10.0 CONCLUSIONS AND RECOMMENDATIONS..........................................................5
11.0 LIMITATIONS.................................................................................................................5
12.0 REFERENCES..................................................................................................................6
FIGURES
Figure 1: Site location map
Figure 2: Monitoring well location
APPENDICES
Appendix A: Monitoring Well Boring Log
Appendix B: Analytical Laboratory Results
Appendix C: Earth Consultants Report
Appendix D: Geotech Consultants Report
Appendix E: Department of Ecology Opinion Letters
Appendix F: Application For Authorization to Use
60-207601/601OR115.doc Page i of i
Copyright 2000 Kleinfelder,Inc.
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1.0 PROJECT BACKGROUND AND SITE DESCRIPTION
This report summarizes the field procedures, findings and recommendations associated with the
site investigation at the above-referenced property (Figure 1). The site investigation addressed
the issues the Washington Department of Ecology (Ecology) identified in opinion letters dated
March 27, 2000 and June 9, 2000 (Appendix A). The site investigation described herein was
performed in accordance with the Voluntary Cleanup Program (VCP) (Ecology 1999).
2.0 LOCATION
The subject property is located at 2880 — Northeast 3'd Street in Renton, Washington. The
subject property is bounded on the north by an apartment complex; on the west by an
undeveloped parcel of land; on the south by undeveloped land; and on the east by a King County
Public Health office and a Parks Department shop and storage yard.
3.0 TOPOGRAPHY AND GEOLOGY
At the time of this report, the subject property is approximately seven acres, undeveloped, and
level with steep slopes on the western and southern borders. The subject property is a former
gravel pit in which ash and waste materials from World War H housing projects were disposed.
The gravel pit was backfilled over time to the current grade with clean fill material. A
geotechnical investigation which included 11 test pits excavated to depths of up to 15 feet
revealed dense brown and gray silty sand with gravel (Earth Consultants 1999). Pieces of wood,
brick, asphalt, glass, and ceramic material were also noted in some test pits. Soils were
described as moist but no groundwater was observed in any of the test pits. An environmental
site investigation revealed brown silty sand, gray sandy silt, and fine to medium gravel in soil
boring completed to depths of up to 62 feet (Geotech Consultants 2000). The subject property is
located at the top of a plateau that slopes steeply to the west and south.
4.0 RELEASE INFORMATION AND SITE CHARACTERIZATION
The subject property is a former gravel pit excavated to approximately 60 feet below the existing
surface grade. The gravel pit was backfilled with a relatively small amount of demolition wastes
as evidenced by the observation of wood debris, glass, ceramic material, and chunks of brick,
60-207601/601 OR I 15.doc Page 1 of 6
Copyright 2000 Kleinfelder,Inc.
asphalt, and concrete. The majority of the backfill material has been clean soil. No chemical
releases are known or suspected to have occurred on the subject property.
Analysis of soil samples collected from depths of up to 30 feet below ground surface from three
boring locations revealed the presence of a small, relatively well-defined area of hydrocarbon-
affected soil (Geotech Consultants 2000). Diesel-range hydrocarbons at a maximum
concentration of 1,300 mg/kg were observed in one boring (B-3) at a depth of 20 feet but were
not detected in the same boring at a depth of 30 feet. Heavy oil-range hydrocarbons were
observed in the same boring at a depth of 20 feet at a maximum concentration of 1,900 mg/kg,
but were not detected at a depth of 30 feet. Gasoline-range hydrocarbons were either not
detected or were present at a concentration below the MTCA Method A soil cleanup level of 100
mg/kg. The BTEX compounds (benzene, toluene, ethylbenzene, and xylenes) were not detected
although very low concentrations of ethylbenzene and xylenes (0.13 and 0.34 mg/kg,
respectively) were observed on one of three borings at a depth of 30 feet. Analysis of soil
samples for PAHs, PCBs, and metals revealed that these potential contaminants were either not
detected or were present at concentrations well below the MTCA Method A soil cleanup levels.
A sample of water that had seeped into boring B-3 was analyzed for petroleum hydrocarbons and
was found to contain diesel-range hydrocarbons at 2,100 •g/L and heavy oil-range hydrocarbons
at 15,000 •g/L. This sample, however, contained sediment to which hydrocarbons may have
adsorbed and may not represent actual groundwater conditions. The site characterization report
described the source of this water as a seep and suggested that it may not represent true
groundwater (Geotech Consultants 2000).
The site characterization report also applied the Interim TPH Policy to an evaluation of the
hydrocarbon-affected soil and concluded that the soil did not pose a direct contact hazard nor
was it likely to leach to groundwater and reach a concentration that exceeded the MTCA Method
A groundwater cleanup level (Geotech Consultants 2000). Ecology concurred with the Interim
TPH Policy analysis and the conclusion that soil did not pose an unacceptable hazard under a
residential or commercial land use scenario (letter from Nnamdi Madakor/Ecology to Tim
Johnson/Geotech Consultants, March 27, 2000). Ecology, however, requested additional
investigation of groundwater by installing and monitoring a well.
5.0 GROUNDWATER INVESTIGATION
On June 22, 2000, Kleinfelder installed a monitoring well on the subject property at the location
of the boring from which the seep water sample was collected in Geotech Consultants (2000),
60-207601/601OR115.doc Page 2 of 6
Copyright 2000 Kleinfelder,Inc.
boring B-3. The Kleinfelder well was screened from a depth of 15 feet to 25 feet to cover the
depth (20 feet below the existing grade) at which the seep sample was collected. Kleinfelder
completed an initial boring for installation of the well to a depth of 20 feet, however, the drill
cuttings were almost entirely bentonite, which indicated that we had indeed located boring B-3.
Kleinfelder then instructed the drillers to move three feet north of the initial boring. This boring
was completed in the expected fill material and the well was installed. A soil sample composited
from drill cuttings obtained at five-feet intervals from five to 25 feet below existing surface
grade was analyzed by NWTPH-Dx for the presence of diesel-range hydrocarbons. No
hydrocarbons were detected at the method reporting limits of 20 mg/kg for kerosene/jet fuel and
diesel/fuel oil, or at 40 mg/kg for heavy oil. The analytical laboratory report for this soil sample
is included as Appendix D. Kleinfelder returned to the subject property on June 28, 2000 to
develop and sample the well. No groundwater was encountered in the well, which indicates that
a regional or perched aquifer does not exist within the depths explored.
6.0 PREVIOUS INVESTIGATIONS
Previous investigations include a geotechnical engineering study (Earth Consultants 1999), a
Phase I environmental site assessment (Geotech Consultants 1998), a CERCLA site inspection
by an EPA contractor, and a Seattle-King County Health Department report (SKCHD 1985)
describing methane and non-specific gas analysis and leachate analysis of a Mt. Olivet Creek
water sample. These previous investigations are summarized below:
Earth Consultants (1999). A geotechnical engineering study was performed to evaluate the
suitability of the subject property for a single family home residential development. Eleven test
pits were completed to a depth of up to 15 feet below the existing surface grade. Although this
was not an environmental site assessment, the standard of care exercised by geotechnical
engineering consultants includes observations of subsurface conditions that may indicate the
presence of hazardous materials. This report did not describe any signs of discolored soils,
liquids, or odors that would suggest the presence of hazardous materials. Also, no groundwater
was encountered in any of the test pits to the depths explored. The presence of wood debris,
glass, ceramic material, brick, concrete, and asphalt in some of the test pits were noted in this
report.
Geotech Consultants (1998). A Phase I environmental site assessment did not reveal any
"specific contamination problem affecting the subject property...". This report was conducted in
accordance with ASTM Standard E 1527, Standard Practice for Environmental Site
60-207601/601 OR I 15.doc Page 3 of 6
Copyright 2000 Kleinfelder,Inc.
Assessments: Phase I Environmental Site Assessment Process, and, therefore, meets the standard
of care practiced by environmental professionals.
Seattle-King County Health Department(1985). A limited investigation of the subject property
was conducted by the Seattle-King County Health to evaluate the presence of methane from the
landfill and the potential migration of leachate to nearby Mt. Olivet Creek. This report
concluded that methane gas was not detected at concentrations greater than trace amounts in
three boreholes on the subject property and that the water sample from the creek showed no
evidence of leachate contamination.
7.0 SELECTION OF CLEANUP STANDARDS AND REMEDIAL
ACTION
Selection of cleanup standards and a remedial action was not necessary given the absence of
groundwater and the observation that all chemicals for which analyses were conducted (Geotech
Consultants 2000) were present at concentrations below MT CA Method A soil cleanup levels or
hydrocarbon concentrations acceptable under the Interim TPH Policy (Ecology 1997, 1998).
8.0 SELECTION AND IMPLEMENTATION OF CLEANUP ACTION
A cleanup action was not necessary for groundwater given the absence of groundwater. A
cleanup action was not necessary for soil given that all chemicals for which analyses were
conducted (Geotech Consultants 2000) were present at concentrations below MTCA Method A
soil cleanup levels or hydrocarbon concentrations acceptable under the Interim TPH Policy
(Ecology 1997, 1998).
9.0 CONFIRMATION SAMPLING
Confirmation sampling was not necessary for soil or groundwater. The composite soil sample
collected from the well installation boring contained no evidence of hydrocarbon contamination.
The absence of groundwater precluded the need for groundwater sampling.
60-207601/601 OR I 15.doc Page 4 of 6
Copyright 2000 Kleinfelder,Inc.
10.0 CONCLUSIONS AND RECOMMENDATIONS
Kleinfelder concludes that the subject property is not affected by chemical contamination at
concentrations that exceed MTCA Method A soil cleanup levels or hydrocarbon concentrations
that exceed acceptable levels under the Interim TPH Policy (Ecology 1997, 1998). Therefore,
Kleinfelder recommends:
• Abandonment of the monitoring well installed at the former location of
Geotech Consultants' boring B-3 in accordance with applicable regulations.
• Submission of a request for a No-Further-Action designation from Ecology
with regard to environmental issues on the subject property.
11.0 LIMITATIONS
The groundwater exploration described herein was performed under Voluntary Cleanup Program
guidance to address the environmental concerns of Ecology at the subject property as stated in
opinion letters dated March 27, 2000 and June 9, 2000. The scope of work described in this
report satisfies the level of effort to which Ecology agreed in their June 9, 2000 opinion letter.
Although risk can never be eliminated, more detailed and extensive investigations yield more
information, which may help to better understand and manage site risks. Since such detailed
services involve greater expense, we ask our clients to participate in identifying the level of
service that will provide them with an acceptable level of risk. Please contact the signatories of
this report if you would like to discuss this issue of risk further.
Land use, site conditions (both on-site and off-site) and other factors will change over time.
Since site activities and regulations beyond our control could change at any time after the
completion of this report, our observations, findings and opinions can be considered valid only as
of the date of the site visit.
Any party other than Northward who would like to use this report shall notify Kleinfelder of
such intended use by executing the "Application for Authorization to Use" included as Appendix
F to this document. Based on the intended use of the report, Kleinfelder may require that
additional work be performed and that a revised report be issued. Non-compliance with any of
these requirements will release Kleinfelder from any liability resulting from the use of this report
by any unauthorized party.
No warranty, either express, or implied is made.
60-207601/6010RI15.doc Page 5 of 6
Copyright 2000 Kleinfelder,Inc.
12.0 REFERENCES
Ecology. 1997. Interim Interpretive and Policy Statement: Cleanup of Total Petroleum
Hydrocarbons. Toxics Cleanup Program, Washington State Department of Ecology, Olympia,
Washington. Ecology Publication Number ECY-97-600.
Ecology. 1998. Interim TPH Policy Update. Memorandum from Carol Kraege, Toxics Cleanup
Program, Washington State Department of Ecology, Olympia, Washington. Ecology Publication
Number ECY-98-604.
Ecology. 1999. Voluntary Cleanup Program Guidance. Department of Ecology, Olympia,
Washington. Ecology Publication Number 97-604.
SKCHD. 1985. Abandoned Landfill Study. Seattle-King County Health Department.
60-207601/6010RI15.doc Page 6 of 6
Copyright 2000 Kleinfelder,Inc.
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LEGEND
MW-2,gk Monitoring well number and
approximate location
NOT TO SCALE
Undeveloped Property FIGURE
2880 Northeast 3rd Street Site Plan
Renton, WA 2
KLEINFELDER 60-2076-01
a
a
a
SOIL CLASSIFICATION CHART
MAJOR DIVISIONS SYMBOLS TYPICAL
GRAPH LETTER DESCRIPTIONS
.'• .'' WELL-GRADED GRAVELS,GRAVEL-
CLEAN • b'• bl GW SAND MIXTURES, LITTLE OR NO
GRAVEL GRAVELS •• •� FINES
AND
GRAVELLY (LITTLE OR NO FINES) °�° °o Q° POORLY-GRADED GRAVELS,
o c, GP GRAVEL-SAND MIXTURES, LITTLE
SOILS O 0 'C OR NO FINES
0
COARSE GRAVELS WITH o GM SILTY GRAVELS,GRAVEL-SAND-
GRAINED MORE THAN 50% FINES O o SILT MIXTURES
SOILS OF COARSE
FRACTION
RETAINED ON NO. APPRECIABLE AMOUNT CLAYEY GRAVELS, GRAVEL-SAND-
4 SIEVE OF FINES) FA GC CLAY MIXTURES
SW WELL-GRADED SANDS,GRAVELLY
CLEAN SANDS SANDS,LITTLE OR NO FINES
SAND
MORE THAN 50% AND (LITTLE OR NO FINES)
OF MATERIAL IS POORLY-GRADED SANDS,
LARGER THAN NO. SANDY SP GRAVELLY SAND, LITTLE OR NO
200 SIEVE SIZE SOILS FINES
MORE THAN 50% SANDS WITH SM SILTY SANDS,SAND-SILT
OF COARSE FINES MIXTURES
FRACTION
PASSING ON NO.4
SIEVE (APPRECIABLE AMOUNT SC CLAYEY SANDS, SAND-CLAY
OF FINES) MIXTURES
INORGANIC SILTS AND VERY FINE
ML SANDS,ROCK FLOUR,SILTY OR
CLAYEY FINE SANDS OR CLAYEY
SILTS WITH SLIGHT PLASTICITY
INORGANIC CLAYS OF LOW TO
SILTS MEDIUM PLASTICITY,GRAVELLY
FINE AND LESS ID LIMIT
AN 0 C'L CLAYS, SANDY CLAYS,SILTY
GRAINED CLAYS _ _ _ CLAYs, LEAN CLAYS
SOILS — OL ORGANIC SILTS AND ORGANIC
SILTY CLAYS OF LOW PLASTICITY
INORGANIC SILTS,MICACEOUS OR
MORE THAN 50% M H DIATOMACEOUS FINE SAND OR
OF MATERIAL IS SILTY SOILS
SMALLER THAN
NO.200 SIEVE SIZE SILTS LIQUID LIMIT INORGANIC CLAYS OF HIGH
AND GREATER THAN 50 CH PLASTICITY
CLAYS
O H ORGANIC CLAYS OF MEDIUM TO
HIGH PLASTICITY,ORGANIC SILTS
HIGHLY ORGANIC SOILS PT PEAT, HUMUS,SWAMP SOILS WITH
„ HIGH ORGANIC CONTENTS
NOTE: DUAL SYMBOLS ARE USED TO INDICATE BORDERLINE SOIL CLASSIFICATIONS
K L E I N F E L D E R SOIL CLASSIFICATION LEGEND
Copyright 1999
Project # 60-2076.01 1 FIGURE A-1
TESTING PROGRAM
LABORATORY FIELD U.S.C.S.
w WELL/PIEZO W WWs F F c7W F 8 .o t w .W9 W o SOIL DESCRIPTION
x CONSTRUCTION .a aH �W W a a o.oa
W FW rnw E. A . °u X C z
W E. OFF .V, Q Co 0" 0.
A 3 O O g? , M y SURFACE:native grass Z
U a a z O
0 a wU
Silty SAND(SK,dark-grey,slightly W U
SM moist,medium dense,fine-to
medium-grained,some organic material, A a
chunks of concrete. d
z
�A
FW
g Az
zW
20 MW-1-5 C
20 U W
zQ
OA
w
10 �'
6 MW-1-10 w 3
7 wz
15 E"o
AU
z o
z4
Bentonite from an old boring(FII.L).
FELL F F
�F
15 oW
~zz
' C Y
d
zA
cz
20 aC
aU
1.5 Boring terminated at 21.5'bgs on 6/22/00. a
Groundwater was not encountered during w
drilling. Boring was backfilled withEn F
bentonite chips on 6/22/00. �,C
w F
FC
C
DATE DRILLED:6-22-00 SURFACE ELEVATION(feet): N/A DRILLING METHOD:HSA Auger
LOGGED BY:AIS TOTAL DEPTH(feet): 21.5 DRILLER:Cascade Drilling <
REVIEWED BY:Scott Dwyer DIAMETER OF BORING(in):N/A CASING SIZE:N/A
Renton Highlands FIGURE
k4KLEINFELDER Renton, WA A - 2
GEOTEC NICAL AND SOILS AND MATERIALS TESTING ENTAL BORING
BORING LOG
PROJECT NUMBER: 60-2076-01 MW-1 PAGE 1 of 1
TESTING PROGRAM
LABORATORY FIELD U.S.C.S.
.a c „
w WELL/PIEZo w F F W H 9 a wa w a SOIL DESCRIPTION
F CONSTRUCTION a OgZ a .�� zW W �9 z
0
asW 0. a `nz
Ga 3O SURFACE:native grass C
z o ..
0
No samples taken from 0'to 15'bgs. w
w�
�w
5 oW
, UW
z�
'a w
wF
�x
10 ; F3
Zz
0
zcn
15- 9 MW-2-15 SM Silty SAND(Slut),dark-grey,moist, w
6 04 medium dense,fine-to medium-grained, Cn z
trace gravel. x
zq
oz
20
z
; 10 MW-2-20 a o
10 w
10 �F
ce
xo
25 _ _ _ _ _
5.5 100/3" ON F:4: Concrete 1"re cove . — — — — —
onng temunated at gs on .
Groundwater was not encountered during
drilling. Boring was converted into
monitoring well on 6/22/00.
O
DATE DRILLED:6-22-00 SURFACE ELEVATION(feet): N/A DRILLING METHOD:HSA Auger oa
0.
LOGGED BY:AIS TOTAL DEPTH(feet): 25.5 DRILLER:Cascade Drilling C
REVIEWED BY:Scott Dwyer DIAMETER OF BORING(in):N/A CASING SIZE:2"
Renton Highlands FIGURE
KLEINFELDER Renton, WA A - 3
GEOTEC SOILSL AND AND MATERIALS TESTING ENTAL GINEERS BORING LOG
PROJECT NUMBER: 60-2076-01 MW-2 PAGE 1 of 1
APPENDIX A
FIELD EXPLORATION
E-8307-3
August 12, 1999• Subsurface conditions at the site
exploration was performed on Aug depth of fifteen feet below the
Our field exP its to a maximum Construction, using a rubber-
were by excavating eleven test p A&D O.uality
were explored its were excavated by
existing grade. The test p
tired backhoe, acing from site boundaries. The locations
Approximate test pit locations were determined by Pa the degree implied by
the method used.
the test pits should be considered accurate on y
of are shown on the Test Pit Location Plan, Plate • ied
These approximate locations
monitored by a engineer from ouresentat ve samples,
The field exploration Was continuously of each test pit, obtained rep
les were visually
pertinent site features. Same resented on
the soils encountered levels,the
and observed P •fication System which ►s presented
measured groundwater
it samples were placed in closed containers andre
classified in accordance with the Unified Soil Classification
clas Representative s
Plate A1 , Legend.
for further examination and testing. s represent our
to our laboratory through Al2. The final log samples. The
resented on Plates A2 tests of field samp es In
Test Pit Logs are p sand the results of the laboratory
retations of the field l09 ent the approximate bound he
the soil shownlon the logs
interp s repres
stratification eltran transit-tons may
be more gradual. The consistency o of the trench
actuality, t
fort required to excavate the soil, the stability
was estimated based
on the of
walls, and other
LETTER TYPICAL DESCRIPTION
GRAPH SYMBOL
SYMBOL Gravel-Sand
JOR DIVISIONS O e GW Well-Graded Gravels, Fines
MA W Mixtures,Little Or No
C ° G . 0 9 Poorly-Graded Gravels,Gravel-
Gravel Clean Gravels r
r GP Little Or No Fines
And fines) � ' . 9P Sand Mixtures,
Gravelly (little or no t Gravels,Gravel-Sand-
soils GM silty
Coarse gm Silt Mixtures
Grained Than ravel-Sand
Soils More Gravels With Clayey Gravels.G
50% Coarse appreciable GC 9C Clay Mixtures
Fraction Fines amount
of fines) Gravelly
Retained On amount of Well-Graded Sands,
� Fines
No.4 Sieve SW SW Sands, Little Or No
°° ° o Graded Sands, Gravelly
° o poorly- No Fines
Sand Clean Sand Little Or
And fines) �:Ayia;: �<'+ SP S Bands,
(little or no p
Sandy >.•r: :>:': Sand- Silt Mixtures
Than Soils SM Silty Sands,
More Sm
50% Material Clay Mixtures
Larger Than More Than With Sands, Sand
No.200 Sieve 50% Coarse Sands(appreciable SC SC Clayey Flour,Silty-
Fraction Fines(aDP Very Fine Sands,Rock
Size No.4 amount of fines) Slight Plasticity
passing Inorganic Silts 8 Clayey Silts wf
Sieve I I ML mi Clayey Fine Sands; Plasticity,
IIII Low To Medium Lean
Inorganic Plasticity-
.lays g ndy C III aYs. Silty Clays.
CL CI Gravelly Clays,
Liquid Limit And Organic
Fine Silts Than 50 Organic Silts A Plasticity
And Less I I I I OL Silty Clays Of Low Fire
Grained Clays I I I I OI iatomaceous
Soils 1 I I I Inorganic Silts,Micaceous Or D
MH mh Sand Or Silty Soils
Inorganic Clays Of High
CH Plasticity. Fat Clays
More Than Limit ch To High
e Material Silts Liquid Than 50 Clays Of Medium
S is Than And Greater OH Organic organic
Silts
Smaller oh Plasticity,
No.200 Sieve Clays ///// Soils
Size Peat, Humus, Swamp
_ PT With Nigh Organic Contents
Highly Organic Soils
Humus And Duff Layer
Topsoil
Highly Variable Constituents
Fill
report is necessary
repo for a proper understanding of the nature
text of thisof the material preserlted in the attached logs.
The discussion in the te
DUAL SYMBOLS are used to Indicate bor
derllne soil classification.
I 2•O.D.SPLIT SPOON SAMPLER
NE READING,tst 24- I.D.RING OR SHELBY TUBE SAMPLER
IRVA
C T PENETROMETER READING,tsf
qu �,dry we
Wight WATER OBSERVATION WELL
MOISTURE,
P SAMPLER PUSHED ERED GROUNDWATER
SAMPLE NOT RECOVERED Q DEPTH OF ENCOUNTERED
* Ibs.per cubic ft. DURING EXCAVATION
� DRY DENSITY, W�DATE
LL LIQUID LIMIT,% 1 SUBSE�ENT GROUNDWATERLEVEL
PI PLASTIC INDEX
LEGEND
E301-1 Consultants Inc. '99 Plate 1
W56 Wavinamxw,J xxi,iui+
No.8307-3 Date Sept.
! ('awaxlvi,a:il1'a,�thrt'n'Gax>WYt
,t�! ` Proj.
Sheet of
Test Pit Log 1 1
Project Name: Test Pit No.*
The Wilshire Plateau Date: Tp-1
Job No. Logged bT 8112199
Ground Surface Elevation:
8307-3 KME
Excavation Contactor:
A&D
Notes:
_ surface Conditions: Depth of Topsoil &Sod 2
L U E
General W - E . , D � F►I1
Notes (%) SAND with gravel,dense,moist(Fill)
SM Brown silty
1
2
10.9
3 -grades to gray
4
5
6
7
8
9 -grades to medium dense
10
11
12
13
14
15 Test pit terminated at 15.0 feet below e)dstjng grade.No groundwater
encountered during eg avation.
0
w Test Pit Log
The Wilshire Plateau
nth Cpn,SUlta InC' Renton,Washington
10 -1mKal Fngh �•C �4 Fijmm n^e^ral
0
Checked t�1E Date
9115199 Plate A2
Date Sept-'99 engineering tests.anah�stitshe
a GLS ory hole,modified or Interpretation by
' Dvm• at the time and location of this eft r �lity for the use
Proj.No. 83'J I cted re merit our otxservatio� a cannot accept
. nditions depi E____..,tee. five of other times and locations
w
Sheet of
Test Pit Log 1 1
Project Name: Test Pit No.:
The Wilshire Plateau Date: Tp-2
Job No. logged by. 8112199
Ground Surface Elevation:
8307-3 KME
ce,ation Contactor.
ABED
Notes: Depth of Topsoil &Sod 2"
Surface Conditions:
y N o
to t n. U �
General w a E o D T feces,dense, moist
Notes (%> U �' _ SAND With gravel and a few wood p
SM Brown silty
(Fill)
1
2
3
4
5
15.1
6
7
8
s Graysilty SAND with gravel and brick pieces, medium dense, mom
SM Fill
10
11
12
13
14
it terminated at 15.0 feet below existing grade.No groundwater
15 Test P excavation.
encountered during
0
u; Test Pit Log
R The Wilshire Plateau
earth Consultants Inc. Renton,Washington
F Fnvtmnn erxil x�rnti-'i Plate A3
`�,animal Env, Date 9/15/99
Checked KME engineering tests,analysis ar
GLS Date Sept.�99 oratory hole,modified by etatron by other
Drm. rrsrbriity for the use or interpr
w Proj.No. 83IJ"I esent our observat, at the time and loo S.cati e�n of a��rho
' ce conditions depicted repr esentative of other times and locxtr
Subsurf? -n—a not n�essanry rep(
Test Pit Log
Sheet of
Project Name:
The Wilshire Plateau 1 1
Job No. Logged by: Date: Test Pit No.:
8307-3 1 KME 8/12J99 TP-3
Excavation Contactor. Ground Surface Elevation:
A&D
Notes:
surface conditions: Depth of Topsoil &Sod 2"
V O = d Ln
General
Notes M p cM � N
SM Brown silty SAND with gravel,dense, moist(Fill)
1
2
3 SM Gray silty SAND with gravel, medium dense to dense, moist to wet
18.0 (Fill)
4
s -asphalt pieces
-48%fines
s
7
8
9
10 SM Brown silty SAND with gravel, medium dense, moist(Fill)
11
12
13
14
1s Test pit terminated at 15.0 feet below existing grade. No groundwater
encountered during excavation.
m
0
U
W
Test Pit Log
Eac h Consultants Inc. The Wilshire Plateau
8 Renton,Washington
J
H
a
Proj.No. 8307-3 Dwn. GLS Date Sept.'99 Checked KME Date 9/15/99 Plate A4
Subsurface conditions depicted represent our observations at the time and location of this e)ooratory hole,modified by engineering tests,analysis and
judgment. They are not necessarily representative of other times and locations.We cannot accept responsibility for the use or interpretation by others of
Information presented on this log.
Test Pit Log
Sheet of
Project Name: 1 1
The Wilshire Plateau
Job No. Logged by: Date: Test Pit No.:
8307-3 KME F8/12/99 TP-4
Ground Surface Elevation:
Excavation Contactor.
A&D
Notes:
Surface Conditions: Depth of Topsoil &Sod 2"
General T(W./ � C u ai E
Notes o W
SM Brown silty SAND with gravel and few wood pieces,dense, moist(Fill)
SM Gray silty SAND with gravel, medium dense, moist(Fill)
2
3
4
5
22.2
6
7
8
9
10 Test pit terminated at 10.0 feet below eAsting grade. No groundwater
encountered during excavation.
a
U
W
Test Pit Log
Earth Consultants Inc. The Wilshire Plateau
Gcorectnh-al FYi2hxcta(;cblogt�nhFnvimnnirnral SclriltL`,"� Renton,Washington
J
F
a Plate Al
Date Se '99 Checked KME Date 9/15/99
W Proj.No. 8307-3 Dwn. GLS Pt
�iment Theyare of necessarily representativereprresentative of other times and loocatioons at line u,tic and �tion of this We cannot)a iccept rreesponsibility for th hole,modifiede use or engineering
by thers of
information prsented on this log.
Test Pit Log sheet of
Project Name: 1 1
The Wilshire Plateau Date: Test Pit No.:
.lob No. jogged�= 8/12/99 TP-5
8307-3 }CI\IlE Ground surface Elevation:
Excavafion Contactor.
A&D
Notes:
surface conditions: Depth of Topsoil &Sod 2"
U O d (A �O
L
General W a E E cn E
Notes (%) � o cn cn
Brown silty SAND with ravel,dense, moist(Fill)
SM g
1
2 SM Gray silty SAND with gravel,dense, moist(Fill)
3
4
13.7
5
6 SM Brown silty SAND w'Ith gravel and a few wood pieces,dense, moist
(Fill)
7
8
SM Gray silty SAND with gravel,dense, moist(Fill)
9
10
11
12 Test pit terminated at 12.0 feet below existing grade. No groundwater
encountered during excavatjon.
a
U
a Test Pit Log
The Wilshire Plateau
CO Earth Consultants Inc.
& ,�,R,,,��,Ix,m�v> Renton,Washington
�rrtlmlCdl F7�ghK:ct�.CT<�R'
GLS Date Sept.'99 � KMEnd
Date 9/15/99 Plate A6
F Proj.No. 8307-3 Dwn.
orato hole,modified by engineering tests,ana others of
re esentative of other times and{ovations.We cannot accept respoMbiiitY for the use or interpretation by
Subsurface conditions depicted represent our observations at the time and location of this ry
judgmerrt. They are not necessarily Pr
Test Pit Log
Sheet of
Project Name: 1 1
The Wilshire Plateau
Job No. Logged try. Date: Test Pit No.:
8307-3 KME 8/12/99 TP-6
Ground Surface Elevation:
Excavation Contactor.
A&D
Notes:
u o s ar o
Surface Conditions: Depth of Topsoil &Sod 2"
General W a CL
E COTLL
E
Notes cn
SM Brown silty SAND with gravel,dense, moist(Fill)
1
2
s SM Gray silty SAND with ravel and a few wood,glass and ceramic
pieces,dense, moist(Fill)
4
11.9 5
SM Gray brown silty SAND with gravel,dense, moist(Fill)
6
7 SM Brown silty SAND with gravel and asphalt pieces, dense, moist(Fill)
8
9
10 Test pit terminated at 10.0 feet below eAsting grade. No groundwater
encountered during excavation.
0
U
W
M
Test Pit Log
Earth Consultants Inc. The Wilshire Plateau
C,corect nk'al Fn¢hxcrs.G-cBt»6Fnvirc�nxrud�clMrt Renton,Washington
0
a Plate A7
W Proj.No. 8307-3 Dvm. GLS Date Sept.'99 checked KME Date 9/15/99
ity others of
Subsurface conditions depicted represent our obserand
vations at the time and location of this e�loratory hole,modified by engineering tests,analysis er
judgment. They are not necessarily representative of other times and locations.We cannot acceptr risibility for the use or in elation by
information presented on this log.
Test Pit Log
Sheet of
Project Name: 1 1
The Wilshire Plateau
Job No. Logged by. Date: Test Pit No.:
8307-3 KME 8/12/99 TP-7
Ground Surface Elevation:
Excavation Contactor.
A&D
Notes:
Surface Conditions: Depth of Topsoil &Sod 2"
General
W t 'a a U �
Notes (%) p LL a � T
E
SM Brown silty SAND with gravel,dense, moist(Fill)
1
2
3 SM Gray silty SAND with gravel,dense, moist(Fill)
4
12.3
5
6
7
8
9
10 Test pit terminated at 10.0 feet below e)asting grade. No groundwater
encountered during excavation.
N
U
W
Test Pit Log
! Farth Consultants Inc. The Wilshire Plateau
Gorrc,'tnlcai Fng7rKcas, &Fnvlmnnxnral SCYrnrU'—EL Renton,Washington
F
Proj.No. 8307-3 Dwn. GLS Date Sept.199 Checked KME Date 9/15/99 PlateLU
A8
Subsurface conditions depicted represent our observations at the time and location of this exploratory hole,modrfied by engineering tests,analysis and
judgment. They are not necessarily representative of other times and locations.We cannot accept responsibility for the use or interpretation try others of
information presented on this log.
Test Pit Log sheet of
Project Name: 1 1
The Wilshire Plateau Test Pit No.:
Logged by Date:
Job No. 8/1 tigg TP-8
8307-3 KME Ground Surface Elevation:
Excavation Contactor.
A&D
Notes:
Surface conditions: Depth of Topsoil &Sod 2"
General W $ C E CL
Notes (%) ❑ � cn
SM Brown silty SAND with gravel, cobbles and glass, ceramic and asphalt
pieces,dense, moist(Fill)
1
2 -18%fines
3
9.6
4
5
6 SM Gray silty SAND with gravel, medium dense, moist to wet(Fill)
20.6 7
8
9
10
11
12 Test pit terminated at 12.0 feet below eksting grade. No groundwater
encountered during excavation.
m
a
U
W
Test Pit Log
co �l h Consultants Inc' The Wilshire Plateau
G�aezymfcal FnR�y&C-- rx Renton,Washington
a Checked KME Date 9/15/99 Plate A9
Date Sept. 99 on of trim ry ana s and
I Proj.No. 8307-3 Dwn. GLS others of
rvations at the time and responsibility for the use or interpretation by
Subsurface co�are not n�ecessanY fePrnesentat�rvee of other times and locations.We
cannot accept respoe�m���engineering tests,
judgment. They
information presented on this log.
Test Pit Log sheet of
Project Name: 1 1 1
The Wilshire Plateau Test Pit No.:
Logged
� Date:
Job No. 8/12/99 TP-9
8307-3 KME Ground Surface Elevation:
Excavation Contactor.
A&D
Notes:
surface conditions: Depth of Topsoil &Sod 2"
U L �O
General W CL
E c(UL LL E m E
Notes (%) a U cn
SM Brown silty SAND with gravel,dense, moist
t
2 SM Gray silty SAND with gravel and occasional wood pieces,dense,
moist
3
4
a$ 5 SM Gray silty SAND with gravel,dense, moist
6
8
9
10
11
12 Test pit terminated at 12.0 feet below existing grade. No groundwater
encountered during excavation.
0
U
W
Test Pit Log
Earth Consultants Inc. The Wilshire Plateau
C�:orccimicalFn�n'> G t"&F.nomnnxnralSid—ti-, Renton,Washington
Date 9/15/99 Plate A10
F Prcj.No. 8307-3 Dwn. GLS Date Sept.'99 checked K11IIE needs tests,analysis and
hole,modfied try engi 9
trl' for the use or interpretation by others of
subsurface conditions depicted represent our observations at the time and location of this e�loratory
judgment. They are not necessarily representative of other times and locations.We cannot accept responsi ay
information presented on this log.
Test Pit Log sneer or
Project Name: 1 1
The Wilshire Plateau Test Pit No.:
b�g� Date:
Job No. 8/12/99 TP-10
8307-3 KME Ground Surface Elevation:
Excavation Contactor.
A&D
Notes:
Surface Conditions: Depth of Topsoil &Sod 2"
U 6 L N O
General W a u v E cn E
Notes (%) o in 7) in
SM Brown silty SAND with gravel,dense, moist(Fill)
2
3
10.8
a SM Gray silty SAND with gravel, medium dense, moist(Fill)
s
s -concrete pieces
7
20.9
8
9
10 Test pit terminated at 10.0 feet below e)asting grade. No groundwater
encountered during excavation.
e
0
U
W
Test Pit Log
Earth Consultants Inc. The Wilshire Plateau
c� ��Fngnx:�s.Gcobgt»&Fnvi=n Mril`;cicnrL�'s Renton,Washington
Proj.No. 8307-3 Dwn. GLS Date Sept.'99 Checked KME
Date 9/15/99 Plate A11
orato hole,modfied by engineering tests,analysishensdof
Subsurface conditions depicted represent our observations at the time and location of this ell rY responsibility for the use or interpretation by
judgment. They are not necessarily representative of other times and{ovations.We cannot accept respo tty
information presented on this log.
Test Pit Log Sheet of
1 1
Project Name: Test Pit No.:
The Wilshire Plateau Date: TP-11
,lob No. Logged by: 8112199
Ground Surface Elevation:
8307-3 KME
Excavation contactor.
ABED
Notes:
Surface conditions: Depth of Topsoil &Sod 2"
U N Cn O
t n a U
General W E ? E
Notes (%) � o <n xn (Fill)
SM Brown silty SAND with gravel, medium dense,moist
1
Gray ASHES mbced with sand and glass pieces, loose,moist(Fill)
2
3
4
5
6
nd gravel, medium dense, moist
7 SP-SM Brown poorly graded SAND with silt a
P.
O ♦�
6.5 0
0 9
:a
o-
_0 10
o °
11
°a 12 Test p tt terminated at 12.0 feet below e)asting grade.No groundwater encountered during exaavation.
0
W Test Pit Log
tS inc. The Wilshire Plateau
Earth Consultan Renton,Washington
p I I ccof x mica F"STI,t5.C�' b FTvlrcxin,c:rxai�ctrnt
-i ` Date 9115/919 Plate Al
ahecked KME tests,analysis and
GLS Date Sept-Sept.'99 en ineering others of
D _ orato hole,modrfied by 9
Proj.No. 8307-3 r n' 14 for the use or interpretati°n by
Subsurface conditions ece�ssarity reprnesentatiivrvavee of other t mes Ons at and locationstiWe cannot a pt �Po
judgment_ They are not n
I�ff.mation presented on this log.
APPENDIX B
LABORATORY TEST RESULTS
E-8307-3
,:,h Consuhents, Inc.
HYDROMETER IN ANALYSIS
GRAIN SIZE MM
SIEVE ANALYSIS o
00 tD 0 0 No
NUMBER OF MESH PER INCH U.S.STANDARD cn N o Q 0
SIZE OF OPENING IN INCHES 0 0 0 00 00 o o
Od' u7 tD 00
00 N ,d' 009
M N :- '-N n --
10
/ 100
2
go 0
m
Qm Do
80 30 C7
7 m
m
7 40
C� z — O
2 TI 60 50 :17
�c z m
G: m — :0
50 CD
— 60
Y � C
cn 40 70 m
ro m
n
� v � 30 80 --�
�D
n 20 90
c9
c)
X, —
cv 100
n. 10 — 00LO v ro N o
rL�+, M N � p O O O O O O O
�` x 0 o O a co � v M GRAIN SIZE IN MILLIMETERS FINES
rp o o — FINE
D
ro FINE COARSE MEDIUM
� £ """ COARSE SAND
� H.
COBBLES GRAVEL Moisture LL PL
p- N Content (%)
£ H. m DESCRIPTION
N m D Boring or DEPTH USCS
,d Z KEY Pest Pit No. ft. --- ---
D 18.0
oSN Gray silty SAND ---
N O TP-3 3 9.6
Drown silty SAND with gravel
°1 TP-8 3 SM
o
DISTRIBUTION
E-8307-3
A&D Quality Construction
Copies P.O. Box 2552
Renton, Washington 98056
Attention: Annette Demps
^---..t.- t. Inc-
Earth Consultants Inc.
' 1 Gmte-chnic al Engineers.Geologists&Environmental Scientists
September 7, 1999 E-8307-3
A&D Quality Construction
P. 0. Box 2552
Renton, Washington 98056
Attention: Annette Demps
Dear Annette:
We are pleased to submit our report titled "Geotechnical Engineering Study, Proposed
Single-Family Residence Development, Renton, Washington." This report presents the results
of our field exploration, selective laboratory tests, and engineering analyses.
Based on the results of our study, it is our opinion the project can be constructed generally
as planned. Support of the residences may be provided using conventional spread and
continuous foundation systems bearing on the competent existing fill or on structural fill used
to modify site grades. Slab-on-grade floors may be similarly supported.
Due to the depth of fill encountered in our test pits, borings should be drilled prior to
construction to confirm adequate soil exists below the bottom of our test pits.
We appreciate this opportunity to be of service to you. If you have any questions, or if we
can be of further assistance, please call.
Respectfully submitted,
EARTH CONSULTANTS, INC.
Kyle R. Campbell, P.E.
Manager of Geotechnical Services
KME/KRC/bkm
1805-136th Place N.E.,Suite 201,Bellevue,Washington 98005 Bellevue(425)643-3780 FAX(425)746-0860 Toll Free(888)739-6670
GEOTECHNICAL ENGINEERING STUDY
PROPOSED
SINGLE-FAMILY RESIDENCE DEVELOPMENT
NORTHEAST 3RD STREET
RENTON, WASHINGTON
E-8307-3
September 7, 1999
PREPARED FOR
A&D QUALITY CONSTRUCTION
Kristina M. Ellings .E.
Project Engineer
6 �. CAr)f o
h 'Z
Kyle R. Campbel ?7614
Manager of Geotechnic
1(I(g�vU
Earth Consultants, Inc.
1805 - 136th Place Northeast, Suite 201
Bellevue, Washington 98005
(425) 643-3780
Toll Free 1-888-739-6670
A GEOTECHNICAL ENGINEERING der the mistaken impression that simply disclaiming re-
REPORT IS SUBJECT TO sponsibility for the accuracy of subsurface information
always insulates them from attendant liability. Providing
MISINTERPRETATION the best available information to contractors helps pre-
Costly problems can occur when other design profes- vent costly construction problems and the adversarial
sionals develop their plans based on misinterpretations attitudes which aggravate them to disproportionate
of a geotechnical engineering report.To help avoid scale.
these problems, the geotechnical engineer should be READ RESPONSIBILITY
retained to work with other appropriate design profes-
sionals to explain relevant geotechnical findings and to CLAUSES CLOSELY
review the adequacy of their plans and specifications
relative to geotechnical issues. Because geotechnical engineering is based extensively
on judgment and opinion,it is far less exact than other
design disciplines.This situation has resulted in wholly
unwarranted claims being lodged against geotechnical
BORING LOGS SHOULD NOT BE consultants.To help prevent this problem,geotechnical
engineers have developed model clauses for use in writ-
SEPARATED FROM THE ten transmittals.These are not exculpatory clauses
ENGINEERING REPORT designed to foist geotechnical engineers'liabilities onto
someone else. Rather, they are definitive clauses which
Final boring logs are developed by geotechnical engi- identify where geotechnical engineers' responsibilities
neers based upon their interpretation of field logs begin and end.Their use helps all parties involved rec-
(assembled by site personnel)and laboratory evaluation ognize their individual responsibilities and take appro-
of field samples. Only final boring logs customarily are priate action. Some of these definitive clauses are likely
included in geotechnical engineering reports. These fogs to appear in your geotechnical engineering report,and
should not under any circumstances be redrawn for inclusion in you are encouraged to read them closely.Your geo-
architectural or other design drawings, because drafters technical engineer will be pleased to give full and frank
may commit errors or omissions in the transfer process. answers to your questions.
Although photographic reproduction eliminates this
problem, it does nothing to minimize the possibility of OTHER STEPS YOU CAN TAKE TO
contractors misinterpreting the logs during bid prepara-
tion.When this occurs,delays, disputes and unantici- REDUCE RISK
pated costs are the all-too-frequent result. Your consulting geotechnical engineer will be pleased to
To minimize the likelihood of boring log misinterpreta- discuss other techniques which can be employed to mit-
tion, give contractors ready access to the complete geotechnical igate risk. In addition,ASFE has developed a variety of
engineering report prepared or authorized for their use. materials which may be beneficial. Contact ASFE for a
Those who do not provide such access may proceed un- complimentary copy of its publications directory.
Published by
THE ASSOCIATION
A F OF ENGINEERING FIRMS
PRACTICING IN THE GEOSCIENCES
8811 Colesville Road/Suite G 106/Silver Spring, Maryland 20910/000 565-2733
0788/3M
TABLE OF CONTENTS
E-8307-3
PAGE
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
General . . . . . . . . . . . . . . . . . . . . . . . . 1
Project Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
SITE CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Subsurface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Groundwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Laboratory Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
DISCUSSION AND RECOMMENDATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Site Preparation and General Earthwork . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Slope Fill Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Foundations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Retaining and Foundation Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Slab-on-Grade Floors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Seismic Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Excavations and Slopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Site Drainage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Utility Support and Backfill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Pavement Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
LIMITATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Additional Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
APPENDICES
Appendix A Field Exploration
Appendix B Laboratory Test Results
ILLUSTRATIONS
Plate 1 Vicinity Map
Plate 2 Test Pit Location Plan
Plate 3 Slope Fill Placement
Plate 4 Typical Footing Subdrain Detail
Plate 5 Utility Trench Backfill
Plate Al Legend
Plates A2 through Al2 Test Pit Logs
Plate 131 Grain Size Analyses
Earth Consultants, Inc.
GEOTECHNICAL ENGINEERING STUDY
PROPOSED SINGLE-FAMILY RESIDENCE DEVELOPMENT
NORTHEAST 3RD STREET
RENTON, WASHINGTON
E-8307-3
INTRODUCTION
General
This report presents the results of the geotechnical engineering study completed by Earth
Consultants, Inc. (ECI) for the proposed single-family residence development in Renton,
Washington. The general location of the site is shown on the Vicinity Map, Plate 1 . The
purpose of this study was to explore the subsurface conditions at the site and based on the
conditions encountered to develop geotechnical recommendations for the proposed site
development.
Project Description
We understand it is planned to develop the site with 48 single-family residences with access
roadway. We anticipate site grades will not be changed significantly with the exception of
filling the slope on the west side of the site.
At the time our study was performed, the site, proposed lot locations, and our exploratory
locations were approximately as shown on the Test Pit Location Plan, Plate 2.
The proposed development will include asphalt surfaced roadway and driveway areas. We
anticipate traffic will consist of passenger vehicles and occasional service and delivery trucks.
If the above design criteria are incorrect or change, we should be consulted to review the
recommendations contained in this report. In any case, ECI should be retained to perform a
general review of the final design.
SITE CONDITIONS
Surface
The subject site is located on the south side of Northeast 3`d Street (see Plate 1 , Vicinity
Map). The site is approximately rectangular in shape, extending about 450 feet in the east-
west direction and 800 feet in the north-south direction. The site is bordered on the west and
south by a gravel pit, on the north by Northeast 3td Street and on the east by commercial
properties.
We understand the site is a gravel pit that was filled over the last several years. A
_ topographic plan dated 1986 shows the top of the fill approximately 440 feet south of
Northeast Third Street. The top of the fill is now approximately 800 feet south of Third
Street. The site slopes down on the south and west sides of the site. Site vegetation
consists of grass and small trees.
F-th Consultants. Inc.
'GEOTECHNICAL ENGINEERING STUDY
A&D Quality Construction E-8307-3
September 7, 1999 Page 2
Subsurface
Subsurface conditions were evaluated by excavating eleven test pits at the approximate
locations shown on Plate 2. Please refer to the Test Pit Logs, Plates A2 through Al 2, for a
more detailed description of the conditions encountered at each location explored. A
description of the field exploration methods is included in Appendix A. The following is a
generalized description of the subsurface conditions encountered.
Our test pits indicate the site is immediately underlain by a four to six inch thick layer of
topsoil and rootmass. This soil unit is characterized by its brown to black color and the
presence of organic material. This soil layer is not considered suitable for use in support of
foundations, slabs-on-grade, or pavements. In addition, it is not suitable for use as a
structural fill, nor should it be mixed with material to be used as structural fill.
Underlying the topsoil in our test pits, we encountered fill. The fill consisted of medium dense
to dense silty sand with gravel (Unified Classification SM). The fill appears to have been
placed near the optimum moisture content and well compacted in most areas. Unsuitable fill
was encountered in the vicinity of test pit TP-11 . The fill consisted of ashes mixed with soil
and should be removed and replaced with structural fill under foundations and pavements.
The fills encountered in the test pits were observed to be competent in most areas. However,
the depth and composition of the fill soil on-site should be confirmed by drilling borings prior
to construction.
Groundwater
Groundwater seepage was not encountered in our test pits. The contractor should be made
aware that groundwater is not static. There will be fluctuations in the level depending on the
season, amount of rainfall, surface water runoff, and other factors. Generally, the water.level
is higher and seepage rate is greater in the wetter winter months (typically October through
May).
Laboratory Testing
Laboratory tests were conducted on several representative soil samples to verify or modify
the field soil classification and to evaluate the general physical properties and engineering
characteristics of the soil encountered. Visual field classifications were supplemented by grain
size analyses on representative soil samples. Moisture content tests were performed on all
samples. The results of laboratory tests performed on specific samples are provided either
at the appropriate sample depth on the individual boring logs or on a separate data sheet
contained in Appendix B. It is important to note that these test results may not accurately
represent the overall in-situ soil conditions. Our geotechnical recommendations are based on
our interpretation of these test results and their use in guiding our engineering judgement. ECI
cannot be responsible for the interpretation of these data by others.
Earth Consultants, Inc.
GEOTECHNICAL ENGINEERING STUDY
A&D Quality Construction E-830
September 7, 1999 Pagee 3
3
In accordance with our Standard Fee Schedule and General Conditions, the soil samples for
this project will be discarded after a period of fifteen days following completion of this report
unless we are otherwise directed in writing.
DISCUSSION AND RECOMMENDATIONS
General
Based on the results of our study, it is our opinion the proposed development can be
constructed generally as planned. Support of the residences may be provided using
conventional spread and continuous foundation systems bearing on the competent existing
fill or on structural fill used to modify site grades. Slab-on-grade floors may be similarly
supported. If site grades will be raised, we should be contacted to provide additional
recommendations. The unsuitable fill encountered in TP-11 should be removed and replaced
with structural fill under foundations and pavements.
The fills encountered in the test pits were observed to be competent in most areas. However,
the depth and composition of the fill soil on-site should be confirmed by drilling borings prior
to construction.
This report has been prepared for specific application to this project only and in a manner
consistent with that level of care and skill ordinarily exercised by other members of the
profession currently practicing under similar conditions in this area for the exclusive use of
A&D Quality Construction and their representatives. No warranty, expressed or implied, is
made. This report, in its entirety, should be included in the project contract documents for
the information of the contractor.
Site Preparation and General Earthwork
Based on the preliminary site plan, it appears site grading will consist of grading installing
underground utilities, grading roadway areas, excavating residence foundations and filling the
slope on the west side of the site. It appears the top of the sloped area on the west side of
the site is just west of the proposed roadway. We anticipate site grades on the rest of the
site will not change significantly.
The building and pavement areas should be stripped and cleared of surface vegetation, organic
matter and other deleterious material. Existing utility pipes to be abandoned should be
plugged or removed so that they do not provide a conduit for water and cause soil saturation
and stability problems.
Based on the thickness of the topsoil layer, encountered at our test pit locations, we estimate
a stripping depth of six inches. Stripped materials should not be mixed with materials to be
used as structural fill.
GEOTECHNICAL ENGINEERING STUDY E-8307-3
A&D Quality Construction Page 4
September 7, 1999
Following the stripping, the ground surface, where structural fill, foundations, or slabs are to
be placed, should be observed by a representative of ECI. Proofrolling may be necessary in
order to identify soft or unstable areas. Proofrolling should be performed under the
observation of a representative of ECI. Soil in loose or soft areas, if recompacted and still
yielding, should be overexcavated and replaced with structural fill to a depth that will provide
a stable base beneath the general structural fill. The optional use of a geotextile fabric placed
directly on the overexcavated surface may help to bridge unstable areas. Unsuitable soil must
be removed from structural areas.
The soils encountered during the site exploration are moisture sensitive due to their high fines
content. As such, in an exposed condition, they will become disturbed from normal
construction activity, especially when in a wet or saturated condition. Once disturbed, in a
wet condition, they will be unsuitable for support of foundations, slabs or pavements.
Therefore, during construction where these soils are exposed and will support new structures,
care must be exercised not to disturb their condition. Consideration should be given to
placement of rock or other methods to protect
i to b d conditions develop, the affected undisturbed
that
soils
support foundations or new structural fill. If d
must be removed and replaced with structural fill. The depth of removal will be dependent
on the level of disturbance developed during construction. Given the above, a summer
earthwork schedule is recommended.
Structural fill is defined as compacted fill placed under buildings, roadways, slabs, pavements,
or other load-bearing areas. Structural fill under floor slabs and footings should be placed in
horizontal lifts not exceeding twelve (12) inches in loose thickness and compacted to a
minimum of 90 percent of its laboratory maximum dry density determined in accordance with
ASTM Test Designation D-1557-91 (Modified Proctor). The fill materials should be placed at
or near their optimum moisture content. Fill under opavements and walks should also be
placed in horizontal lifts and compacted to 90 percent of maximum density except for the top
twelve (12) inches which should be compacted to 95 percent of maximum density.
During dry weather, most soils which are compactible and non-organic can be used as
structural fill. Based on the results of our laboratory tests, the existing fill at the time of our
exploration appears to near the optimum moisture content and should be suitable for use in
its present condition as structural fill, provided the grading operations are conducted during
dry weather. Based on laboratory testing, the existing fill has between 18 and 48 percent
fines passing the No. 200 sieve. Soil with fines in this range will degrade if exposed to
excessive moisture, and compaction and grading will be difficult if the soil moisture increases
significantly above its optimum condition.
_� .._.._..tee..._ i..�
GEOTECHNICAL ENGINEERING STUDY
A&D Quality Construction E-8307-3
September 7, 1999 Page 5
If the existing fill cannot be adequately moisture conditioned and compacted then it may be
necessary to import a soil which can be compacted. During dry weather, most non-organic
compactible soil with a maximum particle size of six inches can be used. Fill for use during
wet weather should consist of a fairly well graded granular material having a maximum
particle size of six inches and no more than five percent fines passing the No. 200 sieve based
on the minus 3/4-inch fraction. A contingency in the earthwork budget should be included
for this possibility.
Slope Fill Placement
We anticipate fill will need to be placed on the slope on the west side of the site. In our
opinion, the placement of fill on slopes is generally acceptable, however, where the slope
exceeds 25 percent, the fill should be keyed and benched into the slope.
This process consists of excavating a keyway at the toe of the planned fill. The keyway
should have a width of about six to eight feet and depth of two feet into medium dense to
dense native soil. The slope above the keyway should then be cut into a series of horizontal
to slightly inward sloping benches. Typically, the benches are excavated with a small
bulldozer as the fill is brought up. The width of the benches will vary with the gradient of the
slope, usually the gentler the slope, the wider the benches.
Plate 3, Slope Fill Placement, schematically shows the keyway and benches.
Foundations
Based on the results of our study, it is our opinion the proposed residences may be supported
on a conventional spread and continuous footing foundation bearing on the medium dense to
dense existing fill or on structural fill used to modify site grades. The existing fill is in general
well compacted and free of significant organic material, however if organics or loose
conditions are encountered in foundation excavations the material should be removed and
replaced with structural fill.
Exterior foundation elements should be placed at a minimum depth of eighteen (18) inches
below final exterior grade. In crawl-space areas, the interior footings may be placed on
competent material on the crawl-space surface. Continuous and individual spread footings
should have minimum widths of eighteen (18) and twenty-four (24) inches, respectively.
With foundation support obtained as described, for design, an allowable bearing capacity of
two thousand (2,000) psf for structural fill or the medium dense to dense existing fill can be
used. Loading of this magnitude would be provided with a theoretical factor-of-safety in
excess of three against actual shear failure. For short-term dynamic loading conditions, a one-
third increase in the above allowable bearing capacities can be used.
GEOTECHNICAL ENGINEERING STUDY
A&D Quality Construction E-8307-3
September 7, 1999 Page 6
With structural loading as expected, total settlement in the range of one inch is anticipated
with differential movement of about one-half inch. Most of the anticipated settlements should
occur during construction as dead loads are applied.
Horizontal loads can be resisted by friction between the base of the foundation and the
supporting soil and by passive soil pressure acting on the face of the buried portion of the
foundation. For the latter, the foundation must be poured "neat" against the competent
native soils or backfilled with structural fill. For frictional capacity, a coefficient of .40 can
be used. For passive earth pressure, the available resistance can be computed using an
equivalent fluid pressure of three hundred fifty (350) pcf. These lateral resistance values are
allowable values, a factor-of-safety of 1 .5 has been included. As movement of the foundation
element is required to mobilize full passive resistance, the passive resistance should be
neglected if such movement is not acceptable.
Footing excavations should be observed by a representative of ECI, prior to placing forms or
rebar, to verify that conditions are as anticipated in this report.
Retaining and Foundation Walls
Retaining walls and foundation walls that act as retaining walls should be designed to resist
lateral earth pressures imposed by the retained soils. Walls that are designed to yield can be
designed to resist the lateral earth pressures imposed by an equivalent fluid with a unit weight
of thirty-five (35) pcf. If walls are to be restrained at the top from free movement, the
equivalent fluid weight should be increased to fifty (50) pcf. These values are based on
horizontal backfill and that surcharges due to backfill slopes, hydrostatic pressures, traffic,
structural loads or other surcharge loads will not act on the wall. If such surcharges are to
apply, they should be added to the above design lateral pressure. The passive pressure and
friction coefficients previously provided in the foundation section are applicable to retaining
walls.
In order to reduce the potential for hydrostatic forces building up behind the walls, retaining
walls should be backfilled with a suitable free-draining material extending at least eighteen
(18) inches behind the wall. The remainder of the backfill should consist of structural fill. The
free-draining backfill should conform to the WSDOT specification for gravel backfill for walls
(WSDOT 9-03.12(2)). A perforated drainpipe should be placed at the base of the wall and
should be surrounded by a minimum of one cubic foot per lineal foot with three-eighths inch
pea gravel.
Slab-on-Grade Floors
Slab-on-grade floors may be supported on competent existing fill or on structural fill.
Disturbed subgrade soil must either be recompacted or replaced with structural fill.
IGEOTECHNICAL ENGINEERING STUDY
A&D Quality Construction E-8307-3
September 7, 1999 Page 7
Concrete slabs resting on soil ultimately cause the moisture content of the underlying soils to
rise. This results from continued capillary rise and the ending of normal evapotranspiration.
As concrete is permeable, moisture will eventually penetrate the slab resulting in a condition
commonly known as a "wet slab" and poor adhesion of floor coverings.
Therefore, the slab should be provided with a minimum of four inches of free-draining sand
or gravel. In areas where slab moisture is undesirable, a vapor barrier such as a 6-mil plastic
membrane may be placed beneath the slab. Two inches of damp sand may be placed over
the membrane for protection during construction and to aid in curing of the concrete.
Seismic Design Considerations
The Puget Lowland is classified as a Seismic Zone 3 in the 1994 Uniform Building Code
(UBC). Earthquakes occur in the Puget Lowland with regularity, however, the majority of
these events are of such low magnitude they are not detected without instruments. Large
earthquakes do occur, as indicated by the 1949, 7.1 magnitude earthquake in the Olympia
area and the 1965, 6.5 magnitude earthquake in the Midway area.
There are three potential geologic hazards associated with a strong motion seismic event at
this site: ground rupture, liquefaction, and ground motion response.
The strongest earthquakes in the Puget Lowland are widespread, subcrustal events, ranging
in depth from thirty (30) to fifty-five (55) miles. Surface faulting from these deep events has
not been documented to date. Therefore, it is our opinion, that the risk of ground rupture
during a strong motion seismic event is negligible.
Liquefaction is a phenomenon in which soils lose all shear strength for short periods of time
during an earthquake. Groundshaking of sufficient duration results in the loss of grain to grain
contact and rapid increase in pore water pressure, causing the soil to behave as a fluid. To
have a potential for liquefaction, a soil must be cohesionless with a grain size distribution of
a specified range (generally sands and silt); it must be loose to medium dense; it must be
below the groundwater table; and it must be subject to sufficient magnitude and duration of
groundshaking. The effects of liquefaction may be large total and/or differential settlement
for structures founded in the liquefying soils. It is our opinion the potential for liquefaction
over the site during a seismic event is negligible.
In accordance with Table 16-J of the 1997 UBC, soil type Sp, should be used in design.
Excavations and Slopes
The following information is provided solely as a service to our client. Under no
circumstances should this information be interpreted to mean that ECI is assuming
responsibility for construction site safety or the contractor's activities; such responsibility is
not being implied and should not be inferred.
Earth Consultants, Inc.
'GEOTECHNICAL ENGINEERING STUDY
A&D Quality Construction E-830
September 7, 1999 Pagee 8
8
In no case should excavation slopes be greater than the limits specified in local, state and
Federal safety regulations. Based on the information obtained from our field exploration and
laboratory testing, the existing fill would be classified as Type C by OSHA. Temporary cuts
greater than four feet in height in Type C soils should be sloped at an inclination of 1 .5H:1 V.
If slopes of this inclination, or flatter, cannot be constructed, temporary shoring may be
necessary.
Shoring will help protect against slope or excavation collapse, and will provide protection to
workers in the excavation. If temporary shoring is required, we will be available to provide
shoring design criteria.
Permanent cut and fill slopes should be inclined no steeper than 2H:1 V. Cut slopes should
be observed by ECI during excavation to verify that conditions are as anticipated.
Supplementary recommendations can then be developed, if needed, to improve stability,
including flattening of slopes or installation of surface or subsurface drains. In any case,
water should not be allowed to flow uncontrolled over the top of slopes.
Permanently exposed slopes should be seeded with an appropriate species of vegetation to
reduce erosion and improve stability of the surficial layer of soil.
Site Drainage
Groundwater seepage was not encountered in our test pits, however if seepage is
encountered in foundation or grade beam excavations during construction, the bottom of the
excavation should be sloped to one or more shallow sump pits. The collected water can then
be pumped from these pits to a positive and permanent discharge, such as a nearby storm
drain. Depending on the magnitude of such seepage, it may also be necessary to interconnect
the sump pits by a system of connector trenches.
The appropriate locations of subsurface drains, if needed,should be established during grading
operations by ECI's representative at which time the seepage areas, if present, may be more
clearly defined.
During construction, the site must be graded such that surface water is directed off the site.
Water must not be allowed to stand in areas where buildings, slabs or pavements are to be
constructed. Loose surfaces should be sealed at night by compacting the surface to reduce
the potential for moisture infiltration into the soils. Final site grades must allow for drainage
away from the building foundations. The ground should be sloped at a gradient of three
percent for a distance of at least ten feet away from the buildings, except in paved areas,
which can be sloped at a gradient of two percent.
Footing drains should be installed around the building perimeters, at or just below the invert
of the footing, with a gradient sufficient to initiate flow. A typical detail is provided on
Plate 3.
Earth Consultants, Inc.
,GEOTECHNICAL ENGINEERING STUDY
A&D Quality Construction E-830
September 7, 1999 Pagee 9
9
Under no circumstances should roof downspout drain lines be connected to the footing drain
system. Roof downspouts must be separately tightlined to discharge. Cleanouts should be
installed at strategic locations to allow for periodic maintenance of the footing drain and
downspout tightline systems.
Utility Support and Backfill
Based on the soil conditions encountered, the soils expected to be exposed by utility
excavations should provide adequate support for utilities.
Utility trench backfill is a primary concern in reducing the potential for settlement along utility
alignments, particularly in pavement areas. It is important that each section of utility line be
adequately supported in the bedding material. The material should be hand tamped to ensure
support is provided around the pipe haunches. Fill should be carefully placed and hand
tamped to about twelve inches above the crown of the pipe before heavy compaction
equipment is brought into use. The remainder of the trench backfill should be placed in lifts
having a loose thickness of less than twelve inches. A typical trench backfill section and
compaction requirements for load supporting and non-load supporting areas is presented on
Plate 4.
Pavement Areas
The adequacy of site pavements is related in part to the condition of the underlying subgrade.
To provide a properly prepared subgrade for pavements, the subgrade should be treated and
prepared as described in the Site Preparation and General Earthwork section of this report.
This means at least the top twelve (12) inches of the subgrade should be compacted to 95
percent of the maximum dry density (per ASTM D-1557-91 ). It is possible that some localized
areas of soft, wet or unstable subgrade may still exist after this process. Therefore, a greater
thickness of structural fill or crushed rock may be needed to stabilize these localized areas.
The following pavement section for lightly-loaded areas can be used:
• Two inches of asphalt concrete (AC) over four inches of crushed rock base (CRB)
material, or
• Two inches of AC over three inches of asphalt treated base (ATB) material.
Heavier truck-traffic areas will require thicker sections depending upon site usage, pavement
life and site traffic. We will be pleased to assist in developing appropriate pavement sections
for heavy traffic zones, if needed.
Pavement materials should conform to WSDOT specifications. The use of a Class B asphalt
mix is suggested.
Earth Consultants, Inc.
GEOTECHNICAL ENGINEERING STUDY E-8307-3
A&D Quality Construction Page 10
September 7, 1999
LIMITATIONS
Our recommendations and conclusions are based oeSthn inte formation on materials
prob ded serveus,sand electour
ive
laboratory testing and engineering analyses, the design
experience and engineering judgement. The conclusions ih that level of care and skilltord naa ly
professional opinions derived in a manner consistent
exercised by other members of the profession currently practicing under similar conditions in
this area. No warranty is expressed or implied.
The recommendations submitted in this report are based s m°a the
from those encountered.
pits. Soil and groundwater conditions between testp Y
The nature and extent of variations between our exploratory locations
requestedrto reeval ay not bate the
ecome
evident until construction. If variations do appear, ECI should be
recommendations of this report and to modify or verify them in writing prior to proceeding
with the construction.
Additional Services
As the geotechnical engineer of record, ECI should be retained to perform a general review
of the final design and specifications to verify dtht he thwork and in the design ounantthe
ion
recommendations have been properly interpreted aimplemented
construction specifications.
ECI should also be retained to provide geotechnical,services
arercommend tons and to all w
ing construction. This is to
observe compliance with the design concepts, specificationso
design changes in the event subsurface conditions differ
those
fo mance of thePoundat on
rior to the
start of construction. We do not accept responsibility for the pe
or earthwork unless we are retained to review the construction drawings and specifications,
and to provide construction observation and testing services.
Earth Consultants, Inc.
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/ GeotechnicalEngineers,Geologists&Envkonmentalscientisis
King County Map 656
By Thomas Brothers Maps
Dated 1999 Vicinity Map
The Wilshire Plateau
Renton, Washington
�. NOTE: This plate may contain areas of color.
ECI cannot be responsible for any subsequent Drwn. GLS Date Sept. '99 Proj. No. 8307-3
misinterpretation of the information resulting Checked KME Date 9/10l99 Plate 1
f this plate.
from black & white reproductions 0
.. . .. . .. .... ..
1 28 ;r TP-11I
TP-10I
1 29 I ,
i 27 I1 47 1 1 30 fl -8►TP— +iTP- � 11 4 .
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I I— 21 1t 1 1_01 37 ' 1- t E-8307-3, Sept. 1999
_ _ ao 1 I � - —I
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19 12 _ 21 Proposed Lot Number
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I 'TP-2 \ 13 I
Earth Consultants, Inc.
Scieni�us
Geo,echnical Engineers. _ Icgis,s a Enviironmenral
Test Pit Location Plan
NOTE:This plate may contain areas of color.
subsequent The Wilshire Plateau
ECI cannot be responsible for any Renton, Washington
misinterpretation of the information resulting e
from black&white reproductions of this p t egg Prol. No. 8307-3
Drnm. GLS Date Sep
Checked KME Date 9/13/99 . Plate 2
;l
SCHEMATIC ONLY - NOT TO SCALE
NOT A CONSTRUCTION DRAWING
Il=
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FINAL SLOPE GRADIENT
[SEE TEXTIH ,.:_ EXISTING
GRADE
TYPICAL"BENCH"
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Free draining, organic free, granular material percent afinesmaximum
size of 3 inches, containing no more than 5 P
e No. 200 mesh sieve or
and clay size particles passing th
other material approved by geotechnical engineer.
Key way fill is same as structural fill
6 descreet ibed
above.
Ki S
sloe face. way
should be minimum 2 t e
ep the full length of the P
Approximate original ground line.
NOTES: prior
• Slope should be stripped of topsoil and unsuitable materials
to excavating key way or benches. approximately
• Benches will typically be equal to a dozer blade width,
8 feet, but a minimum of 4 feet. [Horizontal:Vertical I.
• Final slope gradient should be acted
• Final slope face should be densified by over building with comp
o shape or by compaction with dozer or roller.
back t
fill and trimming with a rapid growth deep rooted
slope face w
• Planting or hydroseeding itha l of slope area.
vegetative mat will reduce erosion potent or geotechnical fabric will help
• Use of pegged in place jute matting has an
maintain the seed and mulch in place until the root system
opportunity to germinate. 0
• Structural fill should be h
acted to no less than
placed in thin loose lifts not exceeding
inches in thickness. Each lift soure arationd earth work section
ld be man
the degree specified in the site P p laced until compaction
of this report. No additional lift should be p
is achieved.
SLOPE FILL PLACEMENT
' Consultants Inc. The Wilshire Plateau
Earth Co Renton, Washington
Gracctu;K;v rrav+re*s. s,s 6 Env{,a�'e"'a15c1eTu�
Dated 9/10/99 Plate 3
n.wn GLS Date Sept. '99 Checked KME
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Slope To Drain
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Fabric °• e
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SCOACONSSTRUCTII
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LEGEND
I Um Surface seal; native soil or other low permeability material.
-• -•• Fine aggregate for Portl
and Cement Concrete; Section 9-03.1(2) of the
•:�-'a�;J; WSDOT Specifications.
O Drain pipe: perforated or slotted rigid PVC pipe laid with perforations or
slots facing down;tight jointed;with a positive gradient.Do not use flexib e
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lines. Wrap with Mirafi 140 Filter Fabric or equivalent.
TYPICAL FOOTING SUBDRAIN DETAIL
The Wilshire Plateau
Farth Cons±T_�t Inc. Renton, Washington
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G E O T E C H 13256 Northeast,Washington
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Bellevue,Washington 98005
CONSULTANTS, INC. (425)747-5618 FAX(425)747-8561
February 24, 2000
JN 99415E
Northward Homes
1560 — 140th Avenue Northeast, Suite 100
Bellevue, Washington 98005
Attention: Dick Gilroy
Subject: Preliminary Summary of Environmental Findings
Undeveloped Parcel
2880 Northeast 3rd Street
Renton, Washington
Dear Mr. Gilroy:
In response to your recent request, we are pleased to present this summary of our continuing
environmental consulting services for the property at 2880 Northeast 3rd Street in Renton,
Washington.
PROJECT BACKGROUND
Site History
Based upon our review of previous reports and historical plans, it appears that the property was
once the site of a gravel pit. Gravel extraction appears to have started in the early 1940's and
continued through the 1980's. The majority of the property has been brought up to a level even
with Northeast 3rd Street and the adjoining eastern property. The western and southern margins
slope steeply down to a former gravel pit.
Previous geotechnical explorations on the subject property completed by Geotech Consultants, Inc.
and others found uncontrolled fill to the maximum explored depth of 17 feet. The upper several
feet of fill consisted of medium-dense, silty sand with some gravel and broken concrete.
Underlying this material was finer grained soil with more organic material and construction debris.
Research completed by the Seattle-King County Health Department revealed that the subject
property and surrounding area was part of a landfilling operation begun in the 1940's and received
uncontrolled fill. No records were kept regarding waste disposal practices. The close proximity of
several industries, including Boeing and Pacific Car and Foundry (PACCAR), raises the possibility
that hazardous materials were part of the waste. This general area was investigated by the Health
Department in the mid-1980's for methane and surface water contamination. Methane at trace
levels was found in three of 11 shallow holes on the present site of an ARCO AM/PM Mini-Mart,
200 feet to the northeast. A creek originating at the Mt. Olivet Cemetery, approximately one-half
mile to the southwest, was not contaminated by leachate.
GEOTECH CONSULTANTS, INC.
Northward Homes JN 99415E
February 24, 2000 Page 2
Regional Groundwater Data
To assist in determination of the depth to groundwater, we reviewed a report for a nearby leaking
underground storage tank (LUST) site and the City of Renton's Monitoring and Production Wells
data base.
Our review of a soil and groundwater remediation report for the former Gull Industries, Inc. service
station at 3800 Northeast Fourth Street (3,000 feet to the northeast) revealed that three monitoring
wells were installed on the site in 1994 to assess the depth and condition of groundwater. The
depth to shallow groundwater at this nearby LUST site ranged between 66.34 feet to 67.03 feet
below the surface. Groundwater flow direction measured in September 1995 is toward the west-
northwest.
According to the City of Renton database, monitoring wells 34(A, B, & C) located approximately
1,500 feet south of the subject site suggest that an upper perched water zone is at an elevation of
approximately 225.13 feet above sea level. The majority of the site is at an elevation of 316 feet
above sea level, therefore, a difference of approximately 91 feet, or at least 60 feet below the
lowest elevation of petroleum-affected soil, separates the upper perched water zone. A deeper
aquifer exists at an elevation of about 83 feet above sea level, a difference of more than 232 feet.
The closest drinking water production well (PW-12) is over 5,000 feet south of the subject property.
Based upon topographic differences between the subject site and the production level of this well,
there appears to be at least 617 feet of vertical separation between the water level in the
production well and the lowest confirmed depth of contamination at the subject property. Based
upon the west-northwest groundwater flow direction near the site, it appears that only one of the
production wells (PW-5A) is situated in a downgradient position relative to the subject property.
This well is more than 10,000 feet (nearly 2 miles) northwest of the subject property.
SCOPE OF WORK
To address the environmental concerns and to evaluate the condition of soil and groundwater (if
present), we explored the site using a truck-mounted drill rig. We drilled and sampled three test
borings to a maximum depth of 60 feet. Our work was conducted in accordance with our proposal
P-5040E dated October 26, 1999.
Laboratory Analyses
Based upon the information presented in the Seattle-King County Health Department study
regarding the historical use of the site as a landfill, a variety of contaminants may be present.
Analysis of selected soil samples from each boring were analyzed for total petroleum hydrocarbons
in the gasoline-, diesel-, and oil-range by chromatography (GC) in accordance with Washington
Method WTPHGx for total petroleum hydrocarbons in the gasoline range and EPA Method 8020 for
benzene, toluene, ethyl benzene, and xylenes (BTEX WTPH-HCID). Diesel- and oil-range
hydrocarbons were analyzed by Washington Method WTPH-Dx (extended). Soil samples were
also analyzed for the eight most common metals in accordance with EPA Methods 6010; for
volatile organic compounds (VOCs) in accordance with EPA Method 8260; for semivolatile organic
GEOTECH CONSULTANTS INC
Northward Homes JN 99415E
February 24, 2000 Page 3
compounds (SVOCs) in accordance with EPA Method 8270C; and for polychlorinated biphenyls
(PCBs) in accordance with EPA Method 8082.
Soil samples that contained residual petroleum hydrocarbons above Method A cleanup levels, were
analyzed using gas chromatography in accordance with the Interim Total Petroleum Hydrocarbon
Policy methods for Volatile Petroleum Hydrocarbons (VPH), which included analysis for methyl tert-
butyl ether (MTBE) and BTEX, and Extractable Petroleum Hydrocarbons (EPH). Analysis for
polynuclear aromatic hydrocarbons (PAHs) was conducted by EPA Method 8270. The method
detection limits for the individual analyses are presented in the Laboratory Reports, which is
included with this report as an appendix.
This analytical approach was intended to provide a basis for comparing the site environment to
existing standards offered in the Model Toxics Control Act (MTCA), Chapter 173-340, Washington
Administrative Code.
FINDINGS
Surface
The subject property is an undeveloped parcel of land that covers 7.0 acres. It lies immediately
south of Northeast 3rd Street, between Edmonds Avenue Northeast and Jefferson Avenue
Northeast, in the Renton Highlands area. The Vicinity Map, Plate 1, illustrates the general location
of the site.
The property is situated in the northwest quarter of Section 16, Township 23 North, Range 5 East,
Willamette Meridian, in King County, Washington. The tax identification number, as recorded by
the King County Assessor's Office, is 162305-9062. The entire 7.0-acre lot is undeveloped.
Access to the property is from Northeast 3rd Street on the north. The central portion of the
property is flat and covered by grass, while trees, brambles, and other native vegetation cover the
perimeter. There is a slight rise on the eastern and southern borders of the property. To the south
and the west, the land falls steeply to a former gravel pit.
Land use in the site vicinity is characterized by commercial and residential development and by a
former gravel pit. More specifically, the property is bordered as follows:
North: Northeast 3rd Street borders the property to the north. Directly across this road lies
an apartment complex and an undeveloped parcel of land. A Department of
Transportation storage lot for sand and gravel and an ARCO gasoline station also lie
along the north side of this road.
East: An undeveloped parcel of land, and the maintenance shops and a storage yard for
the King County Parks Department lie to the east. Farther east are the southeast
district office of the Seattle-King County Health Department, a regional storm water
detention facility, and a solid waste transfer station operated by King County.
South: A steep, near-vertical slope borders the property to the south. This slope defines
the boundary of a former sand and gravel pit. The bottom of the pit has been
graded and is covered by low vegetation.
GFOTFCH rnwN i 11 TANTS INC
Northward Homes JN 99415E
February 24, 2000 Page 4
West: To the west of the property is a steep slope and additional land that was formerly
part of the sand and gravel mining operation.
Subsurface
The approximate test boring locations are illustrated on the Site Exploration Plan, Plate 2. We also
refer the reader to the borings logs, appended as Plates 3 through 7, for the specific conditions
encountered at each drilling location.
In general, the subsurface soil in the borings consists of fill consisting of dense to very dense, silty
sand with gravel and concrete rubble. Native, very dense, silty sand was encountered in borings B-
1 and B-3 at about 35 and 50 feet below the surface, respectively.
During drilling, we detected organic vapors with petroleum odors in headspace measurements for
samples obtained from 15 feet below ground surface from boring B-2 and in the 15-, 20-, and 30-
foot samples in B-3. None of the other samples obtained during the drilling had detectable
petroleum vapors. We used a Photovac 2020 Photoionization Device (PID) to measure headspace
vapors in a plastic bag.
Groundwater was not encountered during drilling in any of the borings, however, some seepage
was noted within the fill and native material. A sample of the seepage was collected through the
hollow-stem auger for laboratory analysis.
Laboratory Analyses
Total Petroleum Hydrocarbons
The following table summarizes the analysis for total petroleum hydrocarbons (TPH). Bold and
shaded cells exceed Method A cleanup levels. A copy of the laboratory report is included with this
report as an appendix.
TABLE 1
LABORATORY RESULTS TOTAL PETROLEUM HYDROCARBONS
SOIL SAMPLES'
Sampleoir
Number -J r
B-1 @ 30' ND9 ND ND ND ND ND ND
B-2 @ 15' ND ND ND ND ND ND
B-3 @ 15' ND9 ND ND ND ND 790
B-3 @ 20' ND ND ND ND ND _ 't,30Q„t�
B-3 @ 30' 51 ND ND 0.13 0.34 ND ND
Current Cleanup 100 0.5 40 20 20 200 200
Level10
GEOTECH CONSULTANTS. INC.
Northward Homes JN 99415E
February 24, 2000 Page 5
Notes:
1. Results are reported in parts per million (ppm).
2. Gasoline-range hydrocarbons by Washington Method WTPH-G.
3. B = Benzene.
4. T= Toluene.
5. E = Ethylbenzene.
6. X = Xylenes (total).
7. Diesel-range hydrocarbons by Washington Method WTPH-Dx (extended).
8. Oil-range hydrocarbons by Washington Method WTPH-Dx (extended).
9. ND denotes not detected above the practical quantitation limit.
10. Method A Cleanup Levels - Soil: the Model Toxics Control Act (MTCA) 173-340-740.
Interim Interpretive and Policy Statement Regarding Petroleum Hydrocarbons
The Method B cleanup levels for the site were calculated following guidance offered in the WDOE
Toxics Cleanup Program Interim Interpretive and Policy Statement: Cleanup of Total Petroleum
Hydrocarbons, Ecology Publication Number ECY97-600, January 1997 for commercial properties.
The spreadsheets illustrating our calculations are presented as Table 2. An electronic version of
the Microsoft ExcelTM spreadsheet is included with this report on a floppy disk.
TABLE 2
METHOD B WORKSHEET - SAMPLE B-3 @ 20 Feet
Compound Soil Conc. MUItp.2 H.Q.3 Risk 4 Molecular Moles' Mole ISolubility' Pore DF10 Conc-.@-
• • • • •
Aliphatics
EC 5-6 0.0 81 0.0 0.0 2.80E+01 0.00 20 0.00
EC>6-8 0.0 100 0.0 0.0 4.20E+00 0.00 20 0.00
EC>8- 10 0.0 130 0.0 0.0 3.30E-01 0.02 20 0.00
EC >10- 12 320.0 160 2.0 0.1 2.60E-02 0.01 20 0.00
EC>12- 16 450.0 200 2.3 0.2 5.90E-04 0.00 20 0.00
EC>16-21 211.0 270 0.8 0.1 1.00E-06 0.00 20 0.00
EC>21 -35 690.0 325 2.1 0.1 1.00E-06 0.00 20 0.00
Total Aliphatic 1,671.0 5.21 E-05 0.09
Aromatics
EC>8-10 23.0 120 0.2 0.0 65 0.86 20 0.04
EC>10- 12 198.0 130 1.5 0.1 25 2.63 20 0.13
EC>12- 16 460.0 150 3.1 0.2 5.8 1.23 20 0.06
EC>16-21 212.0 190 1.1 0.1 0.51 0.04 20 0.00
EC>21 -35 340.0 240 1.4 0.1 0.01 0.00 20 0.00
Total Aromatic 1,233.0 20
Benzene 0.0 7.25E-09 0.00E-00 78 0.0 0.0 1780 0.00 20 0.00
c-PAH" 0.5 1.83E-06 9.15E-07 20
Ethylbenzene 0.0 3.13E-05 0.00 20
Toluene 0.0 1.56E-05 0.00 92 0.0 0.0 520 0.00 20 0.00
Total Xylenes &0 1.56E-06 0.00 1 20
GEOTECH CONSULTANTS. INC.
Northward Homes JN 99415E
February 24, 2000 Page 6
Aromatics+g-E-X 1,233.0 1.04E-04 0.13 20
20
Total 0.22" 9.15E-0714 14.515 1 1.0" 0.217
Notes:
1. Soil Conc. = Soil Concentration; Results are reported in parts per million (ppm).
2. Mult. = Residential Multiplier; value provided by WDOE.
3. H.Q. = Hazard Quotient; Soil Concentration times Mult. Cannot exceed "one" for any individual
substance or fraction.
4. Risk is the risk of additional cancers, expressed in a rate of "one-in a population" individual risk
for a substance cannot exceed (one in a million, e.g. 0.000001 or 1x10-6).
5. Molecular Weight = Value provided by the Total Petroleum Hydrocarbon Criteria Working Group
(TPHCWG).
6. Moles = Soil Conc. Divided by Molecular Weight.
7. Mole Fraction = Moles divided by total sum of Moles.
8. Solubility =Value provided by TPHCWG.
9. Pore H20 = Effective Solubility; Mole Fraction multiplied by Solubility.
10. DF = Dilution Factor; default value used: based upon site conditions assumed source area less
than 0.5 acre.
11. Conc. @ Well = Concentration of each fraction that would be in a monitoring well at the
downgradient edge of the source area.
12. C-PAH = carcinogenic polynuclear aromatic hydrocarbons results from EPA 8270 sample B-2-3.
13. Total Hazard Quotient; Cannot exceed 'one" for total of individual substances and/or fractions.
14. Total Risk; Total risk for all substances cannot exceed (one in one hundred thousand , e.g.
0.00001 or 1x10-5).
15. Total Moles = sum of moles.
16. Total Mole Fraction.
17. Total Conc. @ Well = sum of individual fractions that would be in a monitoring well at the
downgradient edge of the source area; comparison to appropriate standard determines if soil
concentration is protective of applicable medium; e.g. groundwater, surface water, etc.
The calculated hazard quotient for the sample with detectable aliphatic and aromatic hydrocarbons
is 0.22, with no individual hazard quotient greater than 0.13. Based upon the absence of
detectable levels of benzene in the samples submitted for analysis and the low calculated risk
factor for additional cancers from the c-PAHs (sample B-2-3) is calculated to be 9.15 x 10-7, with no
individual risk greater than 9.15 x 10-7, there appears to be no increase in risk of additional cancers
attributable to the soil. The concentrations of petroleum in soils remaining onsite are protective of
human health.
We evaluated the soil-to-groundwater pathway using the soil/pore water partitioning model to
predict soil concentrations that would be protective of groundwater. The projected concentrations
in a monitoring well downgradient from the contaminant source (assuming a contaminant source
less than 0.5-acre) for the sample with detectable aliphatic and aromatic hydrocarbons is 0.2 ppm.
Volatile Organic Compounds
Analysis of three selected soil samples, one each from borings B-1, B-2, and B-3, for volatile
organic compounds (VOCs) revealed detectable levels of methylene chloride in all three samples
GEOTECH CONSULTANTS. INC.
Northward Homes A 99415E
February 24, 2000 Page 7
and 0.32 ppm of n-Butylbenzene in the sample from 20 feet in B-3. No other VOCs were detected
above their individual method detection limits. The method detection limits are well below
applicable Method A or Method B cleanup levels. As the methylene chloride was also detected in
the laboratory blank, it is our opinion that this is a laboratory artifact. No cleanup level for n-
Butylbenzene has been established. The complete list of analytes can be found in Laboratory
Reports, appended to this report.
Semi-Volatile Organic Compounds
The following table summarizes the semi-volatile compounds detected. The complete list of
analytes can be found in Laboratory Reports, appended to this report.
TABLE 3
SEMI-VOLATILE ORGANIC COMPOUNDS IN SOIL'
COMPOUNDi CLEANUP
Anthracene ND' 0.10 ND 0.033 24,000
FBenzo(a)a nth race rte�; f ND 0.090 ND 0.033 0.137
Benza(aypyrene Fes' ND 0.12 ND 0.033 0.137
Benzo{k)fluarantheri ND 0.081 ND 0.033 0.137
Benzo(g,h,l]perylene ND 0.099 ND 0.033 NA'
bis(2-Ethylhexy)- 0.13 0.18 ND 0.033 71.4
phthalate
Chrysene ND 0.11 ND 0.033 0.137
Fluoranthene ND 0.32 ND 0.033 3,200
Indeno(12,3 ND 0.099 ND 0.033 0.137
cd)pyrene
Naphthalene ND ND 0.88 0.033 3,200
Phenanthrene ND 0.19 0.69 0.033 NA
Pyrene ND 0.37 ND 0.033 2,400
2-Methylnapthalene ND ND 3.2 0.033 NA
4-Chloroaniline ND 0.48 ND 0.033 320
Sum of_CPAHs "vQ.0825=' ,.:0.5
: �.,.
Notes:
1. Results are reported in parts per million (ppm).
2. MTCA Method B cleanup levels for soil from Model Toxics Control Act Cleanup levels and Risk Calculations
(CLARC II) Update, Publication No. 94-145.
3. ND denotes not detected above the Practical Quantitation Limit (PQL).
4. Carcinogenic polynuclear aromatic hydrocarbons (CPAHs) as defined by WAC 173-340-200 are shaded.
5. NA denotes cleanup level not available.
6. Sum of CPAHs includes one-half of detection limit for compounds not detected.
GEOTECH CONSULTANTS, INC.
Northward Homes JN 99415E
February 24, 2000 Page 8
Analysis of three selected soil samples, one each from borings B-1, B-2, and B-3 for semi-volatile
organic compounds (SVOCs) revealed that none of the detected SVOCs were above their
individual Method B cleanup limits. The sum of c-PAHs detected in the sample from B-2 was also
below the Method A cleanup level of 1.0 ppm.
Polychlorinated Biphenyls
The following table summarizes the analysis for polychlorinated biphenyls (PCB).
TABLE 4
PCB's IN SOIL'
COMPOUNDI o-2(&, I B-3(—&309 PQ
Aroclor 1016 ND ND ND 0.050
Aroclor 1221 ND ND ND 0.050
Aroclor 1232 ND ND ND 0.050
Aroclor 1242 ND ND ND 0.050
Aroclor 1248 ND ND ND 0.050
Aroclor 1254 ND 0.12 ND 0.050
Aroclor 1260 ND 0.12 ND 0.050
Notes:
1. Results are reported in parts per million (ppm).
2. ND denotes not detected above the Practical Quantitation Limit (PQL).
3. MTCA Method A cleanup level for mixtures of PCBs.
Analysis of three selected soil samples, one each from borings 8-1, B-2, and B-3 for PCBs
revealed that the sum of the detected PCBs was below the Method A cleanup level of 1.0 ppm.
Metals
The following table summarizes the metals detected. The method detection limits can be found in
the laboratory reports, appended to this report.
GEOTECH CONSULTANTS, INC.
Northward Homes JN 99415E
February 24, 2000 Page 9
TABLE 5
METALS IN SOIL'
ANAL Tt � �
Arsenic ND' ND ND 10 20.03
Barium 43 75 61 2.5 8,000
Cadmium ND 1.5 ND 0.50 2.03
Chromium 16 31 28 0.50 1003
Lead ND 68 8.0 5.0 2503
Mercury ND ND ND 0.25 1.03
Selenium ND ND ND 10 400
Silver ND 3.1 ND 0.50 400
Notes:
El
1. Results are reported in parts per million (ppm).
2. ND denotes not detected above the detection limit.
3. Method A cleanup levels for soil from the Model Toxics Control Act(MTCA) 173-340-740.
4. Method B cleanup levels for soil from MTCA Cleanup levels and Risk Calculations (CLARC II)
Update, Publication No. 94-145.
Analysis of three selected soil samples, one each from borings B-1, B-2, and B-3 for the eight most
common metals revealed that none of the metals were present in concentrations above their
individual Method A or Method B cleanup limits.
Water
The following table summarizes the TPH analyses for a sample of water seeping into boring B-3.
The method detection limits can be found in the laboratory reports, appended to this report.
TABLE 6
LABORATORY RESULTS TOTAL PETROLEUM HYDROCARBONS
WATER SAMPLE'
Sample _Jj2i____PV
Number V I ii�
B-3 @ 20- ND 9 ND ND ND ND y 4 2T't0
Current Cleanup 5.0 40.0 30.0 20.0 1,000
Level10
Notes:
1. Results are reported in parts pe illion (p b).
2. B = Benzene. l
3. T=Toluene.
4. E = Ethylbenzene.
5. X=Xylenes (total).
6. Gasoline-range hydrocarbons by Washington Method WTPH-G.
7. Diesel-range hydrocarbons by Washington Method WTPH-Dx (extended).
GEOTECH CONSULTANTS, INC.
Northward Homes JN 99415E
February 24, 2000 Page 10
8. Oil-range hydrocarbons by Washington Method WTPH-Dx (extended).
9. ND denotes not detected above the Practical Quantitation Limit.
10. Method A Cleanup Levels - Soil: the Model Toxics Control Act(MTCA) 173-340-740.
Quantification analysis of the water seeping into boring B-3 revealed no gasoline-range
hydrocarbons; and no benzene, toluene, ethylbenzene, or total xylenes above their individual
detection limits. The method detection limits are well below applicable Method A or Method B
cleanup levels. The concentrations of total petroleum hydrocarbons as diesel- and oil-range
hydrocarbons exceeded the Method A cleanup level of 1,000 ppb for total petroleum hydrocarbons..-
The results may be misleading due to the presence of entrained sediment with adhered residual '
petroleum contaminants.
CONCLUSIONS/RECOMMENDATIONS
The purpose of this study was to conduct a preliminary assessment of the condition of soil and
groundwater across the site.
Condition of Soil
Our field observations completed for this phase of work and the results of the laboratory analyses
indicate that soil with residual concentrations of diesel- and oil-range petroleum hydrocarbons
above Method A cleanup levels were identified in two of the three borings completed. For the
sample with the highest residual petroleum concentration, Method B cleanup levels were calculated
in accordance with recently adopted policy guidance, and the concentrations of residual petroleum
hydrocarbons were demonstrated to be protective of human health and the environment. None of
the other contaminants detected (HVOCs, SVOCs, PCBs, or metals) were above their individual
Method A or Method B cleanup levels.
Condition of Groundwater
As a preface to discussion of groundwater contamination at the explored/sampled localities, we
present the following brief discussion of groundwater occurrence beneath the site:
• With regard to groundwater occurrence across the site, it appears that groundwater is
"perched" at an elevation of approximately 225 feet above sea level. A deeper aquifer is
situated about 83 feet above sea level. Seepage was noted in borings in the fill and native
sand and is probably affected by seasonal changes.
• The groundwater flow direction beneath the subject property is not known, but is inferred to
be toward the northwest from documentation of existing monitoring wells in the vicinity.
Based upon the results of analysis of groundwater seepage obtained from one of the borings
completed at this time, it appears that:
GEOTECH CONSULTANTS, INC.
Northward Homes JN 99415E
February 24, 2000 Page 11
• Seepage from boring B-3, has not been impacted by gasoline-range hydrocarbons, or by
benzene, toluene, ethylbenzene, or xylenes.
• The concentration of total petroleum hydrocarbons as diesel- and oil-range hydrocarbons was
above the Method A cleanup level in B-3. The relatively high concentrations may be the result
of entrained contaminated sediment and not truly representative of groundwater conditions.
The findings of our drilling and sampling, review of the nearby LUST site report, and the City of
Renton's Monitoring and Production Wells suggests that at least 50 feet of medium-dense to very
dense, silty sand lies between the lowest level of confirmed contamination at the site and the
uppermost groundwater. The findings also suggest that at least 5,000 feet of horizontal, and over
600 feet of vertical, separation lies between the subject property and the closest City of Renton
production well. Based upon these findings, it is our opinion that the potential for contamination to
migrate from the site into the groundwater is low.
In conclusion, the finding of diesel- and oil-range hydrocarbons above the Method A cleanup level
may be due to sampling groundwater that was not representative of actual conditions. Monitoring
wells would be required to assess actual groundwater condition and flow direction beneath the subject
property.
LIMITATIONS
This preliminary report has been prepared for specific application to this project in a manner
consistent with that level of care and skill normally exercised by members of the environmental
science profession currently practicing under similar conditions in the area, and in accordance with
the terms and conditions set forth in our proposal dated October 20, 1999. This report is for the
exclusive use of Northward Homes and its representatives for specific application to this site. No
warranty is expressed or implied. If new information is developed in future site work, which may
include excavations, borings, or studies, Geotech Consultants, Inc. should be allowed to re-
evaluate the conclusions of this report and provide amendments as required.
The following documents are attached to complete this report:
Plate 1 Vicinity Map
Plate 2 Site Exploration Plan
Plates 3 - 7 Boring Logs
Appendix Laboratory Results
GEOTECH CONSULTANTS. INC.
Northward Homes JN 99415E
February 24, 2000 Page 12
We appreciate our opportunity to provide environmental consulting services on this project. If you
have any questions, or if we can be of further assistance, please do not hesitate to contact us.
Respectfully submitted,
GEOTECH CONSULTANTS, INC.
IL
Timothy A. ohnson
WDOE-Registered Site Assessor
Marc R. McGinnis, P.E.
Principal
Enclosures
TAJ/MRM: alt
GEOTECH CONSULTANTS, INC.
Northward Homes JN 99415E
February 24, 2000 Page 13
REFERENCES
City of Renton. Monitoring and Production Wells— Map and Geologs. February 28, 1997.
GeoEngineers, Inc. Hydrogeologic & Geotechnical Services, Proposed Residential Development,
Cedar Crest Manufactured Home Community, Renton. October 24, 1994.
GeoEngineers, Inc. Report Addendum Hydrogeologic & Geotechnical Services, Infiltration
Ponds/Slope Stability Impacts, Cedar Crest Manufactured Home Community, Renton,
Washington. April 6, 1995.
Geotech Consultants, Inc. Geotechnical Engineering Study, Proposed Blueberry Hill Manufactured
Home Park, Northeast 3rd Street, Renton. JN 98464. December 14, 1998.
Secor International, Inc. Soil and Groundwater Characterization, Former Gull Industries, Incorporated
Station, 3800 Northeast 4th Street. 10 pages, 3 figures, attachments. December 28, 1994.
U.S. Environmental Protection Agency (Region 10). Site Inspection Report for Renton Highlands
Landfill, 2880 Northeast 3rd Street, Renton, Washington. November 24, 1987.
U.S. Geological Survey (USGS). Renton, Washington, 7.5 Minute (1:24,000) Quadrangle. 1949,
photorevised 1968 and 1973.
Waldron, H.H., Liesch, B.A., Mullineaux, D.R., and Crandell, D.R. Preliminary Geologic Map of
Seattle and Vicinity, Washington. Miscellaneous Geologic Investigations Map No. 1-354.
1962.
Washington Department of Ecology. Model Toxics Control Act Cleanup Regulations Chapter 173-
340 WAC. Publication #94-06. Amended January 1996.
GEOTECH CONSULTANTS, INC.
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LEGEND: CONTOUR INTERVAL:2S FEET
SCALE:1"=1,000•
I PROBABLE DIRECTION OF REGIONAL SHALLOW GROUNDWATER FLOW
(Source: U.S. Geologic Survey Map of Renton, Washington, 1949, Photorevised 1968 and 1973)
VICINITY MAP
GEOTECH UNDEVELOPED PROPERTY
CONSULTANTS,INC. 2880 NORTHEAST 3rd STREET
RENTON, WASHINGTON
Job No: ate: late: 1
99415E ]F'ebruary2000
N
apartments
ARCO
I I I I gasoline
vacant station
apartments land
Highway Department Ll
public health
sand and gravel office
storage
agt 3ca sV�t i land undeveloped
N°rtre cv
0
B-� sa L
i
' N
' B-3
King County Parks Department to
B-2 shops and
o storage yard
N ' '
6' I
former gravel pit "
sb•p slope
undeveloped land
to transfer station
former gravel pit
SITE PLAN
GEOTECH UNDEVELOPED PROPERTY
CONSULTANTS,INC. 2880 NORTHEAST 3rd STREET
RENTON, WASHINGTON
Job No: Date: Plate: 2
99415E February 2000
5 00 BORING B-1
�� �o� <� G5
Goy `��10 0 4 5a "5 Description PM Reading
Grass
5 75/6" 1 No sample.
10 10013' 2 No sample.
15 100/5" 3 Fine to medium GRAVEL with silt, sand,and organic material, 0.0 ppm
moist, very dense.
FILL
20 5016" 4 Same. 0.0 ppm
25 100/4' 5 No sample.
30 60/6' 6 Same, more sand. 0.0 ppm
----------_____--------��--------—------------
IIIIIII
IIIIIII
35 60/6" 7 a.o m
I ' I
Brown silty SAND, medium grained,slightly moist,very dense. PP
I SM I
I I�
1 Ij
IIIIIII
IIIIIII
III I Ill It
40
BORING LOG B-1
GEOTECH UNDEVELOPED PROPERTY
CONSULTANTS,INC. 2880 NORTHEAST 3rd STREET
RENTON WASHINGTON
Job No: I Date: late: 3
99415E I February 2000
BORING B-1
(continued)
�a 4 5a �5 Description PID Reading
p I i I lil l '.�
67/6' O I I I I I li Same. 0.0 ppm
I ( IIIII
IIIIIII
I IIIII l
IIIIIII
IIIIIII
IIIIIII
45 III I I I
5016" 9 it I I Same. 0.0 ppm
I�I I I I I I
IIIIIII
IIIIIII
IIIIIII
IIIIIII
SM
50 6016" 10 III Same. 0.0 ppm
IIIIIII
IIIIIII
IIIIIII
IIIIIII
IIIIIII
IIIIIII
55 11 I I 0.0 ppm 60/6" , , , I , , , Same.
IIIIIII
IIIIIIII
IIIIIIII
IIIIIIII
IIIIIIII
I IIIII Ij
60[7
IIIIIII
50/6" 12 Same. 0.0 ppm
:i it
* Boring drilled to 60.0 feet and sampled to 61.5 feet on November 10, 1999.
* Groundwater not encountered during drilling.
* Headspace measured using a photoionization detector calibrated to isobutylene.
BORING LOG B-1
(continued)
GE OTE CH UNDEVELOPED PROPERTY
CONSMTANTs,INC. 2880 NORTHEAST 3rd STREET
RENTON, WASHINGTON
Job No: Date: Plate: 4
99415E February 2000
�cp BORING B-2
ei
Goy IVa'1° � 4 50 �5G Description PID Reading
Grass.
5 34 1 Gray, sandy,SILT with fine gravel, moist, hard.
7.7 ppm
10 5016" 2 Same. 19.3 ppm
FILL
15 33 3 Same. 15.0 ppm
20 50/6" 4 Concrete in sampler.
Refusal due to concrete.
25
* Boring drilled to 20.0 feet and sampled to 20.5 feet on November 10, 1999.
* Groundwater not encountered during drilling.
* Headspace measured using a photoionization detector calibrated to isobutylene.
BORING LOG B-2
GEOTECH UNDEVELOPED PROPERTY
CONSULTANTS,INC. 2880 NORTHEAST 3rd STREET
RENTON, WASHINGTON
*-_ Job No: Date: Late: 5
99415E February 2000
�e,ti`l �t 5 aa` BORING B-3
_V1 'lot, 5a I �5G Description PID Reading
Grass
5 36 1 Gray sandy SILT with fine gravel, moist, hard. 14.7 ppm
1 0 24 2 Same. 17.9 ppm
1 5 50/6" 3 Same, some hydrocarbon odor. 42.4 ppm
FILL
20 5016 47.7 ppm
" q Same, hydrocarbon odor.
25 50/6" 5 Same, no hydrocarbon odor. 31.7 ppm
30 5016' 6 Same, hydrocarbon odor. 38.1 ppm
35 50/6" 7 Same, no hydrocarbon odor.
17.2 ppm
40
BORING LOG B-3
4 GEOTECH UNDEVELOPED PROPERTY
CONSULTANTS,INC. 2880 NORTHEAST 3rd STREET
RENTON, WASHINGTON
Job No: Date: late: B
I 99415E February 2000
�� BORING B-3
5a
Ka tie�tio 4�<4 a�4� 5p5 (continued) Description PID Reading
5016" 8 x Same, pieces of wood, no hydrocarbon odor. 27.8 ppm
FILL
45
100/1" 9 Same, pieces of concrete. 22.5 ppm
--------------------------------------------------------------------
50
50/6" 10 ;; Brown silty SAND, medium-grained, slightly moist,very dense. 14.7 ppm
55
10015" 11 �U SM I Same. 12.5 ppm
60r— 10015" 12 " ! " Same. 16.9 ppm
�,� ; � �l
* Boring drilled to 60.0 feet and sampled to 61.5 feet on November 10, 1999.
* Groundwater seepage encountered during drilling.
* Headspace measured using a photoionization detector calibrated to isobutylene.
BORING LOG B-3
(continued)
GE OTECH UNDEVELOPED PROPERTY
CONSULTANTS,WC- 2880 NORTHEAST 3rd STREET
RENTON WASHINGTON
Job No: Date: Plate: 7
99415E February 2000
a
c
T
���STATg Off,
O y
STATE OF WASHINGTON JUN 13 20IN
DEPARTMENT OF ECOLOGY r�LEi fELDEk
Northwest Regional Office, 3190 - 160th Ave S.E • Bellevue, Washington 98008-5452 • (425) 649-7000
June 9, 2000
Mr. Scott D. Dwyer, PhD
Kleinfelder, Inc.
2405 140`h Avenue, NE. Suite A 10 1
Bellevue, WA. 98005
Dear Mr. Dwyer:
Re: Request for Review and Opinion Letter, Renton Highlands (Undeveloped Parcel)
2880 Northeast 3rd Street, Renton Washington 98056. TCP I.D. #NW0411.
Thank you for submitting your letter and request for Ecology's review and advise. Ecology
appreciates your initiative in pursuing a voluntary cleanup under the Model Toxics Control
Act.
The Washington State Department of Ecology's Toxics Cleanup Program has reviewed the
following information regarding the Renton Highlands (Undeveloped Parcel) 2880
Northeast 3rd Street, Renton Washington 98056:
1. Letter to Ecology by Kleinfelder, Renton Highlands (Undeveloped Parcel) 2880
Northeast 3rd Street Renton WA. Project No. 60-207601 of June 2, 2000.
Based upon the information listed above, Ecology has determined that, at this time:
1. At a minimum, groundwater-monitoring wells are needed at the site to either
validate or refute whether perched groundwater exits at the site and if it is
indeed impacted by TPH above the MTCA criteria as suggested by the
Geotechnical Reports submitted by Earth Consultants. Please propose depths
and locations of the groundwater monitoring wells for our review.
Please note that because your actions were not, or will not be conducted under a consent
decree with Ecology, this letter is not a settlement by the state under RCW 70.105D.040(4)
and is not binding on the agency. Further action could be required at your site regardless
of how strictly you follow Ecology's advice.
The opinions presented by Ecology in this letter are made only with respect to the
information provided in the report and document(s) listed above. This opinion is only
off,» 00*
Mr. Scott D.Dwyer
Renton Highlands-NORTHWARD
Opinion Letter, VCP NW0411
June 9, 2000
applicable to the specified site (or area of site) and may not be used to justify action at
another site (or area of the site.)
Ecology does not assume any liability for any release, threatened release or other
conditions at the site, or for any actions taken or omitted by any person or his\her agents or
employees with regard to the release, threatened release, or other conditions at the site.
Again, thank you for taking the initiative to voluntarily address the contamination at your
site. Your efforts are recognized by Ecology as a positive step in our work to protect
human health and the environment in Washington State.
If you have any questions regarding this letter, please contact me at (425) 649-7112.
Sincerely,
C�
Nnamdi Madakor,
Senior Hydrogeologist
Toxics Cleanup Program, Northwest Regional Office
NM:nm
cc: Joe Hickey, VCP Coordinator NWRO-TCP
2
Hpr 1J uu uo : .Joa
ST.fh
J
n
STATE OF WASHINGTON
l)FPARTMFNT OF ECOLOGY
Northwest Agiunil Office, 3190- 1601h Ave S.E. Bellevue, Washir rgton 98008-54.52 • (42.5) 649-7000
March 27, 2000
Mr. -f im Johnson
GLOTECH Consultants, Inc.
13256 Northeast 20"' Street, Suite 16
13c;lcvuc, WA 98005 -
Dum- Mr. Johnson:
Re: Request for Review and Opinion Letter, Renton Highlands ((Undevcloped Parcel)
2880 Northeast. .;` Street, Rcntnn Washington PS056. TCP I.D. 4NW041 I.
!'hank you for submitting your Preliminary Summary of Environmental Findings and
rec;uest for Ecology_,y's review and advise. Ecology appreciates your initiative in pursuing a.
voluntary cleanup wider the Modcl Toxics Control Act.
'1-11;; MIS1hington State Department of Ecology's Toxics Cleanup Program has reviewed the
following information regarding the Renton Highlands (Undeveloped Parcel) 2980
Northcast 3' Street; Renton Washington 98056:
1. Gcotcchnical Engineering) Study, Proposed Single-Family Residence
Development Northeast 3" Street Renton WA. Project No. E-8307-3, by Earth
Consultants of September 7, 1999.
2. Preliminary Summary of Environmental Findings, Undeveloped Parcel, 2880
Nortlicast )" Street, Kenton Washington 98056. Project No. JN 99415E, by
Cicotech Consultants, lnc of February 24, 2000.
3. Letter by rick Gilroy, President, NORTHWARD, Undeveloped Parccl, 2S90
Northeast 3'"1 Street, Renton Washington 98056 of February 28, 2000
Based upon the information listed above, Ecology has determined that, at this tine:
I. We concur that the TPH impacted soil does not appear to pose a risk for direct
contact under a residential or commercial land use scenario because the total
liarard quotient value is less than 1. However we disagree on the calculated
result of 0.2mg/l derived for the soil touundwatcr pathway for the reasons
outlined in Table 6. Ecology's interim TPH policy recommends using a
dilution factor (DF) of 20 (Table 2) assuming that contamination is limited only
Apr 13 00 08 : Soa L3tu i tz.Lh L,011JUL I MIl 1 J , • �}� Yam`"
Mr. Tim Johnson
Renton Highlands - NORTHWARD
Opinion Letter, VCP NW0411
March 27, 2000
to the vadose soils. In view of the suggested TPH impact to the site
grouridwate,r (perched or not) as outline in Table 6, a dilution factor of l is
recommended. Our recalculation using a dilution factor of 1, shows a result of
5 my/I for the soil to groundwater pathway and this is greater than the lmg/1
screening criteria under the interim Policy. Screening criteria greater than 1
suggests that potential for groundwater impact exists at the site (Table 6).
2. As parr of the NFA determination, we strongly recommend further assessment
of the site groundwater condition even though the fill has been in place for over
10 years and you plan to cap the area with impervious materials that may
comprise of building foundations and asphalt driveways.
3. Please develop a rninimum of five monitoring wells to assess groundwater
conditions at the site. Criteria for well placement on site shall be based on the
need to delineate site groundwater flow direction, contaminant migration for
appropriate cleanup and monitoring, and the ability of the owner to utilize the
site thrnuoh re-rievelopment..
4. A minimum of seven soil sampling locations drilled to a total depth of
approximately 60 feet below ground surface will be considered adequate to
assess the soil conditions at the site.
5. Keep in mind that this is a former fill area and conduct the soil and growridwai,�-r
investivation appropriately to address relevant exposure pathways pertinent to
the witicipatcd beneficial future use of the site.
Please note that because your actions were not, or will not be conducted under a consent
decree with Ecology, this letter is not a settlement by the state under RCW 70.105D.040(4)
and is not binding oil the agency. Further action could be required at your site regardless
o('how strictly you follow Ecology's advice.
The opinions presented by Ecology in this letter arc made only with respect to the
information provided in the report and docurnent(s) listed above. This opinion is only
applicable to the specified site (or area of site) and may not be used to justify action at
another site (or area of the site.)
Ecology does not assume any liability for any release, threatened release or other
conditions at the site, or for any actions taken or omitted by any person or his\her agerits or
employees with regard to the release, threatened release, or other conditions at the site.
2
Mr. Tim Johnson
Rcnton Highlands - NORTHWARD
Opinion Letter, VCP NW0411
March 27, 2000
Again, thank you for taking the initiative to voluntarily address the contamination at your
site. Your efforts are recognized by Ecology as a positive step in our work to protect
human health and the environment in Washington State.
If you have any questions regarding this letter, please contact me at (425) 649-7112.
Sincerely,
Nnamdi Madakor,
Senior Hydrogeologist
Toxics Cleanup Program, Northwest Regional Office
NM:nm
cc: Joe Hickey, VCP Coordinator NWRO-TCP
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To From ' VV\ n�)gun
ColDept. f �� ` Co.,
1 2XI Phon9 -) ?^
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