HomeMy WebLinkAboutBLD2008-00167 GeoTechnical Report - BLD Engineering / Geo-tech Reports - 5/13/2008 IPA
S I
May 13,2008
Mr.Jim Scholz,County Planner
Mason County Department of Community Development
Mason County Building 1
RH2 ENGINEERING,INC 411 N 5d,Street
http:d1www.rh2.com PCB Box 279
maitboxcW,02.corn Shelton,WA 98584
1.800.720.8052 Sent Via. E-mail to Robert Fink and Sandra Pridmon
Subject: Cofoni Geotechnical Report
WESTERN WASHINGTON
Dear Mr. Scholz:
12100 NE 19511 St,Ste 100
RII2 Engineering has reviewed the following document under our existing contract to
Bothell,WA 98017
provide Geotechnical Engineering review services to Mason County.
(let)425.951.5400
+ Geotechnical Report (Report) 681 NE Collins Lake Drive, Tahuya, Washington,
(tax)425.398.zn4 dated April 16, 2008 by Geotechnical Testing Laboratory, Inc., Olympia,
Washington.
454 West Hatton head We reviewed the Report to evaluate compliance with Mason County Ordinances for
Belhn9ham,WA 98226 geotechnical reports. The author of the document remains responsible for all report and
design issues. We appreciate the level of detail provided in the Report. We recommend the
(let)360.676.oe36 County approve the Report, as it adequately describes site conditions as required by Mason
(fax)360.676.0837 County Resource Ordinance — Landslide Hazard Areas 17.01.100, Seismic Hazard Areas
17.01.102 and Erosion Hazard 1.7.01.104.
The author may want to clarify the active earth pressure design loads to the client. Active
EASTERN WASHINGTON earth pressures are referenced as 150 pounds per cubic foot on page 19 and 35 pounds per
300 Simon Street SE,Suite 5 cubic foot on page 20.
East Wenatchee,WA 98802 This concludes our review of the Report. If you have any questions or comments, please
Rey)509.886.2900 contact me at (360) 876-7960 ext. 5342.
(tax)509.886.2313
Sincerely,
RH2 ENGINEERING,INC.
KITSAP PENINSULA
� . 13tJ tr D.
600 Kitsap Street,Suite 101 ���
Port Orchard,WA 98366
(tef)360.876.7960
Dan Burwell,P.E.
(fax)360876.7988 Project Engineer 3830
SIGNED �� SI D:
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RECEIVED
APR [ 4 iuuo
.MASON COUNTY
G EOTECHNICAL REPORT
681 NE COLLINS LAKE DRIVE
TAHUYA, WASHINGTON
PREPARED FOR
MICHAEL COFONI
BY
GEOTECHNICAL TESTING LABORATORY, INC.
OLYMPIA, WASHINGTON
APRIL 16, 2008
CONTACT INFORMATION
PREPARER INFORMATION
GTL PROJECT NUMBER: 08-0103
CONTACT: CURTIS D.CUSHMAN
ADDRESS: 10011 BLOMBERG STREET SOUTHWEST
OLYMPIA,WASHINGTON 98512
TELEPHONE: (360)754-4612
FACSIMILE: (360)754-4848
EMAIL ADDRESS: GEOTESTLAB@COMCAST.NET
CLIENT INFORMATION
CLIENT: MICHAEL COFONI
HOME TELEPHONE: (360)426-3059
FAX: (360)470-1013
BILLING ADDRESS: P O Box 1105
SHELTON,WASHINGTON 98584
SITE ADDRESS: 681 NE COLLINS LAKE DR.
TAHUYA,WASHINGTON 98588
PARCEL: 223315000005
GPS LOCATION: N47°27' 15.05"W122o 58147.5811
#08-0103 10011 Blomberg Street SW,Olympia, WA 98512 2
Phone#: (360)754-4612 Fax#: (360)754-4848
SCOPE OF UNDERSTANDING
MICHAEL COFONI
P O Box 1105
SHELTON,WASHINGTON 98584
RE: GEOTECHNICAL REPORT
681 E COLLINS LAKE DRIVE
TAHUYA,WASHINGTON 98588
PARCEL#223315000005
N47°27' 15.05"W 122°58147.5811
Mr.Cofoni:
As per your request, we have conducted a soils exploration, foundation evaluation, and slope stability analysis for
the above-mentioned parcel. The results of this investigation,together with our recommendations, are to be found
in the following report. We have provided three copies for your review and distribution.
Representative soil samples were submitted for laboratory testing from the project site (H-1) for analysis of grain
size and shear analysis. The data have been carefully analyzed to determine soils bearing capacities and footing
embedment depths. The results of the exploration and analysis indicate that conventional spread and continuous
wall footings appear to be the most suitable type of foundation for the support of the proposed structure. Some
variability was encountered in comparing the soil profiles of the site. Net allowable soil pressures, embedment
depth,and total expected settlements have been presented for the site later in the report.
We are also a full service laboratory that can meet all your building, testing(compaction, asphalt, concrete), and
inspection needs. We appreciate this opportunity to be of service to you and we look forward to working with you
in the future. If you have any questions concerning the above items, the procedures used, or if we can be of any
further assistance please call us at the phone number listed below.
of Was Respectfully Submitted,
GEOTECHNICAL TESTING LABORATORY
E gineering Geologist
C. 2439 �y
O�Sed Geo�o
Curtis D. Cushman,L.G., L.E.G.
URTIS DEAN CUSHMAN Senior Engineering Geologist
EXPIRES ^'Y SIGNED y✓�'�� ✓
#08-0103 10011 Blomberg Street SW, Olympia, WA 98512 3
Phone#: (360)754-4612 Fax#: (360)754-4848
i
GEOTECHNICAL TESTING LABORATORY
TABLE OF CONTENTS
CONTACTINFORMATION.......................................................................................................................................................2
SCOPEOF UNDERSTANDING.................................................................................................................................................3
TABLEOF CONTENTS..............................................................................................................................................................4
INTRODUCTION........................................................................................................................................................................5
SITECONDITIONS....................................................................................................................................................................6
SurfaceConditions....................................................................................................................................................................6
GEOLOGICALLY HAZARDOUS AREAS.................................................................................................................................8
Landslide Hazard Classification................................................................................................................................................8
SeismicHazard Classification...................................................................................................................................................8
Erosion Hazard Classification...................................................................................................................................................9
SiteGeology............................................................................................................................................................................10
SiteSoils.................................................................................................................................................................................I I
SubsurfaceExplorations..........................................................................................................................................................I 1
SamplingProcedures...............................................................................................................................................................I I
SubsurfaceConditions.............................................................................................................................................................12
Recommendations for Suitability of Onsite Soils as Fill.........................................................................................................13
Theoretical ultimate bearing capacity......................................................................................................................................13
SlopeStability and Analysis....................................................................................................................................................14
Recommendations for Building Setback.................................................................................................................................16
LiquefactionHazard................................................................................................................................................................16
SeismicHazard........................................................................................................................................................................17
Recommendationsfor Erosion Control...................................................................................................................................17
EARTHWORK........................................................................................................................................................................... 18
Recommendations for Site Preparation...................................................................................................................................18
Recommendationsfor Structural Fill.......................................................................................................................................18
Recommendationsfor Cut and Fill Slopes..............................................................................................................................19
Recommendations for Foundation Support.............................................................................................................................19
Recommendations for Floor Slab Support..............................................................................................................................19
Recommendations for Retaining Walls...................................................................................................................................20
MasonCounty Prescribed Wall Design...................................................................................................................................21
Recommendations for Retaining Wall Alternatives................................................................................................................23
Recommendations for Site Drainage.......................................................................................................................................23
SepticImpact...........................................................................................................................................................................23
CONCLUSIONS AND RECOMMENDATIONS......................................................................................................................23
General....................................................................................................................................................................................23
REPORT LIMITATIONS AND GUIDELINES FOR USE........................................................................................................................24
References...............................................................................................................................................................................25
APPENDIX....................................................................................................................................................................................27
BoringLog..............................................................................................................................................................................28
LaboratoryResults..................................................................................................................................................................29
ShearResults...........................................................................................................................................................................31
WellLog.................................................................................................................................................................................32
Figure1 Vicinity Map.............................................................................................................................................................33
Figure 2 Site Plan Attached
Figure 3 Erosion Control Notes Attached
Figure 4 Cross-section Attached
#08-0103 10011 Blomberg Street SW,Olympia, WA 98512 4
Phone#: (360)754-4612 Fax#: (360)754-4848
GEOTECHNICAL TESTING LABORATORY
INTRODUCTION
This report summarizes the results of our geotechnical consulting services for the proposed single-family
residence. The report has been commissioned by Michael Cofoni. The parcel is located along the northern
upslope overlooking Collins Lake. The site is approximately 6.5 miles west of Belfair, Washington. The site is
accessed from the driveway off Collins Lake Drive. The GPS location of the site is shown relative to the
surrounding area on the Vicinity Map, Figure 1,(at the end of this report).
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Our understanding of the project is based on our discussions with Mr. Michael Cofoni. We understand that the
parcel is to be developed with a single-family residence. In general, grading will consist of the excavation of the
foundation, and footings. The proposed septic drain field is located on the north side of property. The
approximate layout of the site is shown on the Site Plan, Figure 2.
The purpose of our services is to evaluate the surface and subsurface conditions at the site as a basis for providing
geotechnical recommendations and design criteria for the project and to satisfy the requirements of the Mason
County Critical Areas Ordinance. Geotechnical Testing Laboratory is therefore providing geologic and hydro
geologic services for the project. Specifically, our scope of services for this project includes the following:
1. A review of the available geologic,hydro geological,and geotechnical data for the site area.
2. A geologic reconnaissance of the site area and surrounding vicinity.
3. Investigation and identification of subsurface conditions at the site by characterizing the exposed
soil,reviewing published well logs, and by drilling.
4. Comparison of site to published geologic maps, previous field investigations, and open file
reports. Inspection of aerial photographs to determine the geomorphology of the site.
5. Laboratory grain size and shear angle analysis for the soil samples collected from the site.
6. Evaluation of the landslide, erosion, and seismic hazards at the site per the Mason County
Critical Areas Ordinance regulations(December 27,2006).
7. Building setbacks determined from dynamic slope stability modeling.
8. Geotechnical recommendations for site grading including site preparation, subgrade preparation,
fill placement criteria (including hillside grading), temporary and permanent cut and fill slopes,
drainage and typical erosion control measures(Figure 3).
#08-0103 10011 Blomberg Street SW,Olympia, WA 98512 5
Phone#: (360)754-4612 Fax#: (360)754-4848
GEOTECHNICAE TESTING LABORATORY
The steepest slope measured onsite was approximately 25 percent in the south central portion of the project site.
The building site is moderately sloped and is well vegetated. As the slopes at the subject site do not exceed 40
percent, Mason County requires that a geotechnical assessment be prepared in accordance with the Critical Areas
Ordinance.
However,the scope of this report has been increased to function as a geotechnical report.
17.01.100ES(1) -- A discussion of general geologic conditions, specific soil types, ground
water conditions, the upslope geomorphology and location of upland waterbodies and
wetlands, and history of landslide activity in the vicinity.
SITE CONDITIONS
SURFACE CONDITIONS
The proposed building site is located in an area of moderate residential development along the northeastern
u land hillside overlookin Collins Lake see aerial hotos below .
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G
Terraserver USA aerial Image Mason County GIS aerial image
At the project site, exploration was conducted on March 21, 2008 by Curtis D Cushman and Prashanta
Lamichhane. The purpose of a site inspection was to physically observe the property and adjacent properties to
identify any recognized geologic conditions. Photographs and visual observations were documented. Site-specific
features were mapped and vegetation noted
The central upper portion of the site will be developed with a single-family residence. The site has a predominant
southern exposure and is well vegetated. Site elevations range from approximately 430 to 470 feet. The general
topography of the site area indicates that drainage flows toward the south toward Collins Lake from the proposed
building locations. The site plan is included as Figure 2.
No evidence of active surface erosion was observed. No surface water flow was observed onsite. No ponding of
water was observed throughout the site. Slumping and sloughing was not observed throughout the site. No
#08-0103 10011 Blomberg Street SW,Olympia, WA 98512 6
Phone#: (360)754-4612 Fax#: (360)754-4848
evidence of deep-seated slope instability was observed onsite. No seeps or springs were observed onsite. Onsite
trees were observed to be straight and vertical.
No wetland features were observed during the site reconnaissance or through the inspection of aerial photographs.
There are several standing water bodies in the area, the closest being Collins Lake immediately south of the
property and at approximately 0.5 miles up north to the property lies Erdman Lake. Both are topographically low.
The southern portion of the site slope ranges from approximately 15 to 25 percent. The selected building
locations have a slope of approximately 10 to 25 percent. The proposed septic drainfield has a slope of
approximately 10 percent.
The site is protected with native vegetation common to the northwest. The vegetation includes fir, hemlock,
maple,alder, and cedar trees as well as sword fern, bracken ferns,blackberry,and grasses. See photos below.
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17.01.100E5(2) -- A site plan which identifies the important development and geologic
features.
A site plan is attached as Figure 2 Site Plan at the end of this report.
17.01.100E5(13) A site map drawn to scale showing the property boundaries, scale, north
arrow, and the location and nature of existing and proposed development on the site.
A site plan is attached as Figure 2 Site Plan at the end of this report.
17.01.100E5(3) -- Locations and logs of exploratory holes or probes.
Location of the exploratory hole is labeled on the Figure 2 Site Plan at the end of this report.
17.01.100E5(4) -- The area of the proposed development, the boundaries of the hazard,
and associated buffers and setbacks shall be delineated (top, both sides, and toe) on a
geologic map of the site.
The area of the proposed development, boundaries of the landslide hazard area, and associated buffers and
setbacks (if necessary) are demarcated on Figure 2 Site Plan is at the end of this report. Appropriate geology is
labeled on Figure 2 Site Plan.
787103 10011 Blomberg Street SW, Olympia, WA 98512 7
Phone#: (360) 754-4612 Fax#: (360)754-4848
GEO`[`ECHNICAL 1UTI RMATOR
17.01.100E5(5) -- A minimum of one cross section at a scale which adequately depicts the
subsurface profile, and which incorporates the details of proposed grade changes.
A cross-section is attached to this report as Figure 4 Cross-section.
GEOLOGICALLY HAZARDOUS AREAS
LANDSLIDE HAZARD CLASSIFICATION
The Mason County Critical Areas Ordinance(17.01.100A1)defines a landslide hazard area as:
The following shall be classified as Landslide Hazard Areas:
a. Areas with any indications of earth movement such as debris slides, eartli lows, slumps and rockfalls (see
figure F.100).
b.Areas with artificial oversteepened or unengineered slopes, i.e. cuts or fills.
c. Areas with slopes containing soft or potentially liquefiable soils.
d. Areas oversteepened or otherwise unstable as a result of stream incision, stream bank erosion, and
undercutting by wave action.
e. Slopes greater than 15%(8.5 degrees)and having the following:
i. Hillsides intersecting geologic contacts with a relatively permeable sediment overlying a relatively
impermeable sediment or bedrock(e.g. sand overlying clay);and
ii. Springs or groundwater seepage.
f Any area with a slope of forty percent or steeper and with a vertical relief of ten or more feet except areas
composed of consolidated rock. A slope is delineated by establishing its toe and top and measured by
averaging the inclination over at least ten feet of vertical relief.
The subject site does not meet the technical criteria for landslide hazard as defined by Mason County.
SEISMIC HAZARD CLASSIFICATION
The Mason County Critical Areas Ordinance(17.01.102A)defines a seismic hazard area as:
1.Areas susceptible to ground failure including the following:
a. Areas with mapped geologic faults until proven inactive;
b. Deep road fills and areas of poorly compacted artificial fill;
c. Areas with artificially steepened slopes (i.e. old gravel pits);
d. Postglacial stream, lake or beach sediments;
e. River deltas;
f.Areas designated as potential Landslide Hazard Areas;
g. Bluff areas;and
h.Areas underlain by potentially liquefiable soils
2. The following criteria may be used as a guide by the County to indicate areas that have a higher likelihood of
meeting the classification criteria above:
a. Areas identified on the Coastal Zone Atlas of Washington, Volume 9, Mason County as Af, Qal, Qa2, Qvc,
Qls, Qos and Qp.
b. Areas identified on the Mason County Soil Survey Map as having slopes greater than 15 percent.
c. Faults identified on "Map Showing Known or Suspected Faults With Quaternary Displacement in the
Pacific Northwest", A.M. Rogers, T.J. Walsh, W.J. Kockelman and G.R. Priest, US Geologic Survey, 1996;
#08-0103 10011 Blomberg Street SW,Olympia, WA 98512 8
Phone#: (360)754-4612 Fax#: (360)754-4848
GEOTECHNICAL TESTING LABORATORY
or described in "Active Faulting Investigations on the Canyon River Fault, Southern Olympic Range,
Washington", T.J. Walsh and K.G. Neal, U.S. Geologic Survey, 1997.
d. Areas underlain by potentially liquefiable soils as shown "Liquefaction Susceptibility Map of Mason
County, Washington"by Stephen P. Palmer, Sammantha L. Magsino,James L. Poelstra, Eric L. Bilderback,
Derek S. Folger, and Rebecca A. Niggemann, September 2004.
This site qualifies as a seismic hazard area because the site is categorized as, "2.b.Areas identified on the Mason
County Soil Survey Map as having slopes greater than 15 percent.
EROSION HAZARD CLASSIFICATION
The purpose of the Erosion Hazard Section (17.01.104A) is to identify areas that present potential dangers to
public health and safety, and to prevent the acceleration of natural geological hazards, and to neutralize the risk to
the property owner from development activities.
Areas in Mason County underlain by soils which are subject to severe erosion when
disturbed. Such soils include, but are not limited to, those for which potential for erosion
is identified in the Soil Survey of Mason County, USDA Soil Conservation Service, 1960,
or any subsequent revisions or additions to this source. These soils include, but are not
limited to, any occurrence of River Wash ("Ra') or Coastal Beaches ("Cg') and the
following when they occur on slopes 15%or steeper:
a.Alderwood gravelly sandy loam ("Ac"and"Ad')
b. Cloquallum silt loam ("Cd')
c. Harstine gravelly sandy loam ("HY9
d. Kitsap silt loam ("Kc')
The soils at the site are mapped as Alderwood gravelly sandy loam (Ab). This site does not meet the technical
criteria of an erosion hazard area.
ti-
74
408-0103 10011 Blomberg Street SW, Olympia, WA 98512 9
Phone#: (360) 754-4612 Fax#: (360) 754-4848
GE®TECHNicA1l1 TnTmG eoRAToRy
SITE GEOLOGY
7
The site is generally situated within the Puget s' "
Sound glacial province. Multiple glacial advances v
deposited the onsite material. During the most ' r
recent Vashon stade (stage) of the Fraser
glaciation (9,000 and 11,000 years ago), glacial till �+
material was deposited over the area.
The figure (right) is a LiDAR image at a 6-foot
resolution The image does not indicate any deep f y`
3.
seated land slide features in the vicinity of the
subject site. f
The site material is composed of compacted " 1 r r
glacial till (gravelly sand with silt). Our site visit ""Y
and drilling confirm the site geology being ,rO
_ .
predominantly of glacial till origin. A description
of the onsite soils is included in the"Boring Logs"
section of the appendix.
The Geological Map of Washington,North West
Quadrant by Dragovich et al,(2002)describes the s
site geology as till,(Qgt). The report reads:
Till(Qgt)— Unsorted, unstratified highly -
compacted mixture of clay, sand, gravel Aeuget S nsort'
and boulder, deposited by glacial ice:May
contain interbedded stratified sand, silt and gravel. Includes parts of Fashon drifts undivided.
The geologic conditions related to waste disposal planning in the southern hood canal area by R.J.Carson and
Mackey Smith(1975)classifies the geology of the area as a till. The report reads:
Till: Till overlain by a thin veneer(generally less than S feet or 1.S meters of sand and gravel; mostly
uplands, slopes generally low, variable surface drainage conditions,
#08-0103 10011 Blomberg Street SW,Olympia, WA 98512 10
Phone#: (360)754-4612 Fax#: (360)754-4848
GEOTECHNICAL TESTING LABORATORY
SITE SOILS
The Soil Survey of Mason County, Washington, USDA Soil Conservation Service(1960)has mapped the site soils
as Alderwood gravelly sandy loam, 5 to 15 percent slopes(Ab). The survey reads,
The Alderwood soils typically formed from mixed gravelly glacial till dominated by acid igneous
rock. It occupies undulating to rolling moraines. In undisturbed areas a 1- to 2-inch mat of very
dark brown, acid organic matter is on the surface. These grades to a thin, dark grayish-brown,
highly organic mineral soil. The surface soil consists of a friable, brown, medium acid gravelly
sandy loam 8 to 13 inches deep. It has a weak granular structure and contains numerous
rounded shot. Below the surface soil, to depths ranging from 18 to 24 inches, is a pale-brown
gravelly sandy loam that is very friable, is single grained, and contains small to moderate
amounts of shot. Between this layer and the cemented till is a 3- to 10-inch layer of very pale
brown gravelly sandy loam. It contains no shot and is firmer but has the same texture as the
layer above. However, it is faintly to distinctly spotted and horizontally streaked with brown and
yellow. The cemented till consists of light-gray, gravelly sandy loam, and it normally occurs at
depths ranging from 24 to 32 inches. It is impermeable to roots and very slowly permeable to
water. The first few inches is usually laminated and streaked with reddish brown and yellow.
.r f Y
Below this, to a depth of many feet, the till is uniformly cemented,fairly uniform light gray, and
medium to strongly acid. A thin mat of roots often lies over the till. The cemented substratum
tends to restrict the rapid downward movement of moisture.
They are described as having good natural drainage. Typically, there is no occurrence of a high
water table. Internal drainage is described as medium. An erosion hazard may exist if the
vegetation is removed; otherwise, the soil has a low erosion hazard in its present condition.
Cementation is usually present. The soils are not considered hydric.
SUBSURFACE EXPLORATIONS
Subsurface conditions at the site were evaluated by drilling on site and reviewing available well logs. No seeps,
seepage, or springs were observed throughout the subject site or offsite to the north. Groundwater was not
encountered at the proposed building locations while drilling. Drinking water will be provided by an offsite
source. Therefore, no well exist onfite and no well is proposed. Refer to the provided well log from nearby area
in the Appendix.
SAMPLING PROCEDURES
The field exploration to determine the engineering characteristics of the foundation materials included a
reconnaissance of the project site, performing a test boring, and recovery of test samples. The test boring was
completed at the site along the proposed building location. The test boring was advanced to 40 feet below the
existing ground surface. The boring location is shown on the Site Plan Figure 2. The test boring was located by
the field technician by means of normal taping and pacing procedures and is presumed to be accurate to within a
few feet. After completion,the test boring was backfilled with excavated soils.
The soil borings were performed with a B 40, hollow stem auger drill rig. Soil changes were noted at the time of
drilling. The boring log was recorded by Mr. Neil Lorenzo on April 9, 2008. The samples obtained by this
procedure were classified in the field by Mr. Neil Lorenzo, identified according to test boring number and depth,
placed in plastic bags to protect against moisture loss, and transported to the laboratory for additional testing.
#08-0103 10011 Blomberg Street SW, Olympia, WA 98512 11
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GEO TECHNICAL TESTING LABORATORY
Standard penetration was measured using a two-inch outside diameter, split-spoon sampler driven by a pin-guided,
140-pound weight, and free falling 30 inches. The blows per six-inch interval were recorded. The first six-inch
drive interval is allowed for seating the sampler.
The blow counts for two six-inch intervals, when combined, yield the Standard Penetration Resistance (N-Value)
of the soils encountered in the sample interval. The SPR is also known as blow counts. The number of blows
required to drive the sampler the last 12 inches provides a measure of the relative density of granular soils or the
consistency of cohesive soils. When the number of blows exceeds 50 for a six-inch or less advancement of the
sampler, refusal is inferred. The results obtained from the Standard Penetration Test, along with other tests and
geotechnical judgments,were used to develop the recommendations of this report.
Soil gradations were determined by laboratory test method ASTM D-2487 that utilizes the Unified Soil
Classification System. The soils laboratory has the following certifications, accreditations,or qualifications:
AASHTO American Association of State highway and Transportation Officials
AMRL AASHTO Materials Reference Laboratory
CCRL Cement and Concrete Reference Laboratory
A2LA American Association for Laboratory Accreditation
ICC International Code Council
SUBSURFACE CONDITIONS
In general, stiff to dense Alderwood gravelly sandy loam (silty sand with gravel) was observed at the surface
throughout the site. Specific soils information is contained in the following"Boring Log"section of the appendix.
Depth to competent soil is approximately 0 to 1 feet as indicated by the sampling process while boring.
Groundwater was not encountered at 40 feet in the test boring. Groundwater seepage or springs were not observed
along site slopes.
►.. 1
ly
Results of individual tests are in the appendix.
408-0103 10011 Blomberg Street SW,Olympia, WA 98512 12
Phone#: (360)754-4612 Fax#: (360) 754-4848
L
RECOMMENDATIONS FOR SUITABILITY OF ONSITE SOILS AS FILL
Onsite soils may be considered for use as structural fill if industry standards are satisfied. Fill material
requirements are found on page 9-31 of the WSDOT Standard Specifications 2006. In general, the native soils
(sand, silt, and gravel) encountered on the site must have less than 10 percent fines (material passing the US No.
200 sieve) to be suitable for use as structural fill. Field analysis of the onsite material indicates that the onsite
surficial material sampled may be used as structural fill.
THEORETICAL ULTIMATE BEARING CAPACITY
Based on our laboratory testing conducted on the sample of material collected from subject site, we have
calculated the theoretical ultimate bearing capacity. The following Terzaghi formula calculates the ultimate
bearing capacity. Using the Figure 6.3, page 173 by Prakash,the bearing capacity factors are determined from the
shear angle. Using a factor of safety of three (3), the theoretical maximum bearing capacity is equal to 6859 psf
using a shear angle of 36-* and a unit weight of 128 pcf. See the following spreadsheet calculation. The IBC
(Table 1804.2)lists the allowable foundation pressure as 2000 psf for silty sand with gravel.
Terzaghi Equation is given by the following formula:
Qd=B (cNc+yDfNq+ %2 yBN7)
c Nc Y Df Nq 05 y B Ny
1 49 128 1 35 0.5 128 2 45
Total Bearing Capacity is: 20578
Using a Factor of Safety of 3 6859
c= unit cohesion 1
Y=soil density 128
B =hooting width 2
D(f)=depth of footing 1
N(c)=bearing capacity factor 49
N(q)=bearing capacity factor 35
N(Y)= bearing capacity factor 45
Qd=Total bearing capacity
Bearing capacity factors taken from, fig 6.3, Soil Dynamics, Shamsher Prakash, Mc Graw Hill Inc. 1981
#08-010 3 10011 Blomberg Street SW, Olympia, WA 98512 1;
Phone#: (360)754-4612 Fax#: (360) 754-4848
SLOPE STABILITY AND ANALYSIS
In general,the undisturbed native soils of the site consist of a mixture of variable amounts of sand and gravel with
minor silts. These soil materials are in a dense condition except where they have been disturbed by weathering
activity.
No evidence of significant surficial erosion was observed onsite at the time of our investigation. Instability of this
nature is typically confined to the upper weathered or disturbed zone, which has been disturbed and has a lower
strength. Raveling and sloughing were not observed along the northwestern slope.
COASTAL ZONE ATLAS does not cover this area.
As previously discussed, weathering, erosion, and the resultant surficial sloughing and land sliding are natural
processes that affect slope areas. Significant weathering typically occurs in the upper 2 to 3 feet and is the result
of oxidation,root penetration,wet/dry cycles and freeze/thaw cycles. Over excavation may be necessary to ensure
the removal of deleterious material. These processes can be managed and the risk reduced through proper
construction of the residence. Erosion control recommendations in the slope and buffer areas are provided in the
"Building Setback"and"Erosion Control"sections of this report.
Excavation and backfilling will occur based on appropriate engineering and earthwork recommendations found in
the following"Earthwork" section. Grading in the building portion of the site should be conducted in accordance
with geotechnical recommendations provided herein.
A single resource by Walsh et al (1991), mapped a geophysical lineament inferred to be a fault trending through
Hood canal in a northeast to southwest direction. The mapped fault is approximately 5 miles west of the project
site.
17.01.100E5(6) -- A description and results of slope stability analyses performed for both
static and seismic loading conditions. Analysis should examine worst case failures. The
analysis should include the Simplified Bishop's Method of Circles. The minimum static
safety factor is 1.5, the minimum seismic safety factor is 1.1. and the quasi-static analysis
coeffients should be a value of 0.15.
Slope stability was modeled using the GeoStudio 2004 program (version 6.20) in both static and dynamic
conditions (Ca = 0.15). Factors of safety were determined using Bishop's, Janbu, and the Morgenstern-Price
methods. The site was modeled using a monolithic layer of cemented silty sand with gravel (see Figure 4 Cross-
section). The onsite sample at 10 feet depth was used to determine shear and cohesion values. The following
values were utilized in the slope model.
Unit weight: 128 pcf
Cohesion: 200 psf
Shear: 36 degrees
See Appendix for the shear test results. As the ground water table is very deep (refer to the well log provided at
the appendix), this site has been modeled using "dry" conditions. The footings will be founded on undisturbed
and unyielding native material.
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G E®TECHN ICAL TESTING ILABoRATokv
Under static conditions, the slope remained stable to deep-seated and shallow failure. See Figure 4 for the cross-
section. The static factor of safety is equal to 4.11 for section "A" along the toe of the slope. Under dynamic
loading, the 3328 computations demonstrated that the slope is not susceptible to surficial raveling or large deep-
seated failure. The following figure illustrates the moment factor of safety for section "A" under the existing
conditions. The critical dynamic slip surface factor of safety is equal to 2.57 for section "A." Mason County
code requires a dynamic factor of safety to be at least 1.1 at the proposed building locations.
Cofoni Slope A
Static Model
FoS 4.11
.' - •'-fir
J
490 -
480
470 -
480 Description:Silty Sand w/Grave �lj
Wt: 128
_ a5o Cohesion:200 i
ul 4411 Phi:36
430
0 20 40 60 On t00 120 140 160 100 200 220 240 260 280
Distance (ft)
Cofoni Slope A
Dynamic Model
FoS 2.57
480
_ -
470
460 Description: Silty Sand w/Gr
Wt: 128
_ 450 Cohesion: 200
LJ 440 Phi: 36
430
0 _u a0 6ii 80 1Du 1t0 1411 160 180 ?n0 220 240 260 280
Distance (ft)
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17.01.100E5(7) -- Appropriate restrictions on placement of drainage features, septic drain
fields and compacted fills and footings, including recommended buffers and setbacks from
the landslide hazard areas.
The previous figure exhibits no need for a building setback as no land slide hazard areas has been identified at the
subject site as a result of our studies. All foundation elements shall be constructed on native material or
engineered fill material.
17.01.100E5(11) -- Specifications of final development conditions such as, vegetative
management, drainage, erosion control, and buffer widths.
RECOMMENDATIONS FOR BUILDING SETBACK
The building Y setback may be measured from the
bottom of the footing to the face of the steep
slope in accordance with the International
Building Code(1805.3.1), see figure to right.
As previously discussed, weathering, erosion and
the resultant surficial sloughing and shallow land
sliding are natural processes that affect slope Setback
areas. To manage and reduce the potential for
these natural processes, we recommend the
following:
No drainage of concentrated surface
g i
water or significant sheet flow onto the sloped areas.
No filling within the setback zone,where applicable.
Trees may be removed as long as the stumps remain in the sloped areas.
No building setback was deemed necessary for this subject site.
From a geotechnical standpoint,there is no need to provide vegetative buffers. However,we recommend the
maintenance of as much native vegetation as possible for the building project and subsequent habitation.
LIQUEFACTION HAZARD
The surrounding undisturbed slopes are well vegetated. The neighboring well log was acquired from the
Washington Department of Ecology. The closest neighboring well log reported that static groundwater level is
142 feet below the surface.
Shaking of the dense glacial till is not apt to produce a denser configuration and subsequently excess pore water
pressures are not likely to be produced. Lacking shallow groundwater,the mixed material (sand, gravel and silt) is
not a likely candidate for liquefaction concerns. Grain-size analyses are found in the Appendix. Based on our
review of the subsurface conditions, we conclude that the site soils are not susceptible to liquefaction. The
following geologic excerpts are available concerning liquefaction potential at the subject site and its vicinity.
The Liquefaction Susceptibility Map of Mason County, Washington by Palmer, Magsino, Poelstra, Bilderback,
Folger, and Niggemann(September 2004)maps the site area as having a very low liquefaction potential.
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GROTECHNICAL TESTING LABORATORY
The Site Class Map of Mason County, Washington by Palmer, Magsino, Bilderback, Poelstra, Folger, and
Niggemann(September 2004)maps the site area as site class C. Site class C is a very stiff soil or soft rock
SEISMIC HAZARD
According to the Seismic Zone Map of the United States contained in the 2006 International Building Code
(IBC,2006), the project site is located where the maximum spectral response acceleration is 45 percent of gravity
(g)•
Based on the subsurface conditions observed at the site, we interpret the site conditions to correspond to a seismic
Soil Profile Type C, for Very Dense Soil and Soft Rock, as defined by Table 1613.5.2 (IBC, 2006). This is based
on blow counts. The shallow soil conditions were assumed to be representative for the site conditions beyond the
depths explored.
17.01.100E5(9) Recommendations for the preparation of a detailed temporary erosion
control plan which identifies the specific mitigating measures to be implemented during
construction to protect the slope from erosion, landslides and harmful construction
methods.
RECOMMENDATIONS FOR EROSION CONTROL
Active surface erosion was not observed on or surrounding the subject site. Evidence of ponding was not
observed onsite. It is our opinion that the potential erosion hazard of the site is not a limiting factor for the
proposed development. Removal of natural vegetation should be minimized and limited to the active construction
areas. Yard landscaping around the home is permissible, but understory growth on the slopes should be
encouraged as much as possible as a deterrent to erosion. Hazard trees located on steep slopes may be removed
only if the stumps remain to deter erosion.
Temporary and permanent erosion control measures should be implemented and maintained during construction
and/or as soon as practical thereafter to limit the additional influx of water to exposed areas and protect potential
receiving waters.
Erosion control measures should include, but not be limited to, silt fences, berms, and swales with ground
cover/protection in exposed areas. Typical erosion control notes and a silt fence detail are included on Figure 2
Site Plan. Any re-contouring of the site will create a need for erosion control measures as recommended above.
17.01.100E5(8) -- Recommendations for the preparation of a detailed clearing and grading
plan which specifically identifies vegetation to be removed, a schedule for vegetation
removal and replanting, and the method of vegetation removal.
( Earthwork should be limited to immediate construction areas and vegetation should remain natural and
\undisturbed where it does not endanger the proposed structure,drainfield, or any other site improvement.
17.01.100E5(12) -- Recommendations for the preparation of structural mitigation or
details of other proposed mitigation.
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i
EARTHWORK
RECOMMENDATIONS FOR SITE PREPARATION
All areas to be excavated should be cleared of deleterious matter including any existing structures, debris,
duff, and vegetation. Based on our observations, we estimate that additional stripping on the order of 12 inches
or more will be necessary to remove the root zone, fill material,and surficial soils containing organics.
Areas with deeper, unsuitable organics should be expected in the vicinity of depressions or heavy vegetation.
Stripping depths of up to 3 feet may occur in these areas. These materials may be stockpiled and later used for
erosion control and landscaping. Surficial material that cannot be used for landscaping or erosion control should
be removed from the project site. No foundation elements shall be constructed on"untested"fill material.
Where placement of fill material is required, the exposed subgrade areas should be proof-rolled to a firm and
unyielding surface prior to placement of any fill. We recommend that trees be removed with the roots, unless
located on a slope. Excavations for tree stump removal in any building area should be backfilled with structural
fill,compacted to the density requirements described in the"Structural Fill"section of this report.
c�uu riffs
If structural fill is needed, we recommend that a member of our staff evaluate the exposed subgrade conditions
after removal of vegetation and topsoil stripping is completed.
Any soft, loose or otherwise unsuitable areas delineated during foundation preparation or probing should be
compacted, if practical, or over-excavated and replaced with structural fill, based on the recommendations of our
report.
RECOMMENDATIONS FOR STRUCTURAL FILL
All fill material should be placed as structural fill. The structural fill should be placed in horizontal lifts of
appropriate thickness to allow adequate and uniform compaction of each lift. Fill should be compacted to at least
90 percent of MDD (maximum dry density as determined in accordance with ASTM D-1557) to within 2 feet of
subgrade and 95 percent MDD in the upper 2 feet. For structural fill below footings, the area of the compacted
backfill must extend outside the perimeter of the foundation for a distance at least equal to the thickness of the fill
between the bottom of the foundation and the underlying soils.
The appropriate lift thickness will depend on the fill characteristics and compaction equipment used. We
recommend that the appropriate lift thickness be evaluated by our field representative during construction.
The suitability of material for use as structural fill will depend on the gradation and moisture content of the soil.
As the amount of fines (material passing No. 200 sieve) increases, soil becomes increasingly sensitive to small
changes in moisture content and adequate compaction becomes more difficult to achieve. During wet weather,we
recommend the use of well-graded sand and gravel with less than 7 percent(by weight) passing the No. 200 sieve
based on that fraction passing the 3/4-inch sieve.
If prolonged dry weather prevails during the earthwork and foundation installation phase of construction, a
somewhat higher(up to 10 percent) fines content will be acceptable. Material placed for structural fill should be
free of debris, organic matter,trash,and cobbles greater than 6 inches in diameter. The moisture content of the fill
material should be adjusted as necessary for proper compaction.
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l>fE' ®TECHNICAL TUTiNG LAsoRATORY
RECOMMENDATIONS FOR CUT AND FILL SLOPES
All job site safety issues and precautions are the responsibility of the contractor providing services and/or work.
The following cut/fill slope guidelines are provided for planning purposes.
Temporary cut slopes may be necessary during grading operations. As a general guide,temporary slopes of 1.5 to
1 (horizontal to vertical) or flatter may be used for temporary cuts in the upper 3 to 4 feet of the glacially
consolidated soils that are weathered to a loose/medium-dense condition. Temporary slopes of I to I or flatter
may be used in the unweathered dense to very dense sands and gravel.
These guidelines assume that all surface loads are kept at a minimum distance of at least one half the depth of the
cut away from the top of the slope and that significant seepage is not present on the slope face (due to recent rain
events). Flatter cut slopes will be necessary where significant raveling or seepage occurs.
Surface drainage should be directed away from all slope faces. Straw, hay, or jute matting shall be used to cover
the exposed soils until permanent vegetation is established. All slopes should be seeded as soon as practical to
facilitate the development of a protective vegetative cover or otherwise protected.
RECOMMENDATIONS FOR FOUNDATION SUPPORT
Where foundation elements are located near slopes between 5 and 30 percent, the footings should be located a
minimum of 2 times the footing width from the slope face (horizontally), and founded in medium dense or denser
native soils or properly prepared structural fill.
We recommend a minimum width for isolated and continuous wall footings to meet IBC 2006. Footings founded
as described above can be designed using an allowable soil bearing capacity of 2,000 psf(pounds per square foot)
for combined dead and long-term live loads in areas of medium dense to dense soils.
The weight of the footing and any overlying backfill may be neglected. The allowable bearing value may be
increased by one-third for transient loads such as those induced by seismic events or wind loads.
Lateral loads may be resisted by friction on the bases of footings and floor slabs and as passive pressure on the
sides of footings. We recommend that an allowable coefficient of friction of 0.40 be used to calculate friction
between the concrete and the underlying soil. Active pressure may be determined using an allowable equivalent
fluid density of 150 pcf(pounds per cubic foot).
We estimate that settlements of footings designed and constructed as recommended will be less than 1 inch, for
the anticipated load conditions, with differential settlements between comparably loaded footings of 'h inch or
less. Most of the settlements should occur essentially as loads are being applied. However, disturbance of the
foundation subgrade during construction could result in larger settlements than predicted.
RECOMMENDATIONS FOR FLOOR SLAB SUPPORT
Slabs-on-grade should be supported on medium dense or dense native soils or on structural fill prepared as
described in the"Structural Fill" section of this report. We recommend that floor slabs be directly underlain by a
synthetic vapor barrier. Below the synthetic vapor barrier, we recommend a minimum 6-inch thickness of coarse
sand and/or gravel containing less than 5 percent fines (by weight). The drainage material should be placed and
compacted to an unyielding condition.
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I
GE+®TECHNICAL TESTING LABORATORY
A synthetic vapor barrier must be used for the control of moisture migration through the slab, particularly where
adhesives are used to anchor carpet or tile to the slab. A thin layer of sand may be placed over the vapor barrier
and immediately below the slab to protect the liner during steel and/or concrete placement. The lack of a vapor
barrier could result in wet spots on the slab,particularly in storage areas.
RECOMMENDATIONS FOR RETAINING WALLS
Retaining walls may be utilized on the sloping portion of the site to retain fill material. The lateral pressures
acting on the subgrade and retaining walls will depend upon the nature and density of the soil behind the wall. It
is also dependent upon the presence or absence of hydrostatic pressure. If the adjacent exterior wall space is
backfilled with clean granular, well-drained soil (washed rock), the design active pressure may be determined
using an active pressure coefficient equal to 0.25 (Ka= 0.25). This design value assumes a level backslope and
drained conditions as described below.
Retaining walls located on or near the toe of a slope that extends up behind the wall should be designed for a
lateral pressure, which includes the surcharge effects of the steep slope in proximity to the wall. Although not
expected at this site,the following data is provided for planning purposes.
For an irregular or composite slope, the equivalent slope angle may be determined by extending a line upward
from the toe of the wall at an angle of 1 to 1 (Horizontal to Vertical)to a point where the line intersects the ground
surface. The surcharge effects may be modeled by increasing the equivalent fluid pressure for flat ground by the
percentage given in the following table:
SLOPE INCLINATION:EQUIVALENT FLUID PRESSURE
Slope Angle Percent Increase Equivalent Fluid Pressure
Horizontal 0% 35 pcf
3H:1 V 25% 44 pcf
2H:1 V 50% 53 pcf
1 H:1 V 75% 61 pcf
If the walls are greater than 4 feet in height, exclusive of the footing, additional design considerations should be
applied. Walls greater than 4 feet in height must be designed by a Professional Engineer.
Positive drainage,which controls the development of hydrostatic pressure, can be accomplished by placing a zone
of coarse sand and gravel behind the walls. The granular drainage material should contain less than 5 percent
fines. The drainage zone should extend horizontally at least 18 inches from the back of the wall. The drainage
zone should also extend from the base of the wall to within 1 foot of the top of the wall. The drainage zone should
be compacted to approximately 90 percent of the MDD. Over compaction should be avoided as this can lead to
excessive lateral pressures.
A perforated PVC pipe with a minimum diameter of 4 inches should be placed in the drainage zone along the base
of the wall to direct accumulated water to an appropriate discharge location.
We recommend that a non-woven geotextile filter fabric be placed between the drainage material and the
remaining wall backfill to reduce silt migration into the drainage zone. The infiltration of silt into the drainage
zone can,with time,reduce the permeability of the granular material.
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The filter fabric should be placed in such a way that it fully separates the drainage material and the backfill, and
should be extended over the top of the drainage zone.
Lateral loads may be resisted by friction on the bases of footings and as passive pressure on the sides of footings
and the buried portions of the wall. We recommend that an allowable coefficient of friction of 0.40 be used to
calculate friction between the concrete and the underlying soil. Passive pressure may be determined by using a
passive pressure coefficient equal to 4(Kp=4).
Mason County has provided a prescribed retaining wall design that may be used for non-bulkhead retaining walls
less than 4 feet in height.
MASON COUNTY PRESCRIBED WALL DESIGN
MASON COUNTY
DEPARTMENT OF COMMUNITY DEVELOPMENT
mason County Bldg.III.428 West Cedar Street
PO Box '32,Sheftr,WA PM84
40 rrw,.v.c .n-ason.wa-ug i3W)427-967- Setfa-liF:�:,�"_1cr?- Etma;WCA82-1,26-P
UPLAND CONCRETE
Prescriptive Design A Installation Standard
DESIGN STANDARDS DO NOT APPLY TO SHORELINE EROSION CONTROL BULKHEADS
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#08-0103 10011 Blomberg Street SW,Olympia, WA 98512 21
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GEOTECHNICAL TESTING ILAsoRATOIkY
Prescriptive Concrete Retaining Wall
Height.,Maximum Eight Feet
Upland concrete retaining walls installed in accordance with the prescriptive design shown on the
reverse side need not be designed by an engineer unless the fdason County Building Dept.determines
special conditions exist. Any retaining gall exceeding eight feet in height or varying from the press nptiv+e
design requires an engineered design.
Location of Retaining Watt
Retaining wall must only be placed against stable slopes, consi4stng of firm. undisturbed soil. Drainage
must be provided as shown with a 4'perforated drain pipe or 2`weep hoes spaced not less than 12 feet
m center. No surcharge oad. such as a building or driwway, may be placed on the retaining wall or
within a distance equa to the vertical height of the retaining vm l un ess an engineered design is
prepared for the add tiena load.
Ground Surface Above Retaining Wail
The ground surface above the retaining wail shall be ess than or equa to 1:1 (i.e. 1-foot vertical to 1-foot
horizontal'.
Retaining Wall Placement
The top of the footing for the retaining wall nxmt be set a ntininxmt of 12 inches below grade. The
footing and wall dimensions shall not be less than outlined in the retaining wal chart. The footing shall
be used on firm,undisturbed earth.
Drainage
A minimum of 12 inches of washed granular drainage materia. shall be placed between the undisturbed
soil are the retaining wal. The drainage materials must be composed of gravel with 1-inch particle
sites. Tkvo-inch weep holes shall be located approximately 6 inches above grade, below the granular
drainage material. spaced not less than 12-feet on center. At the base of the wall. a perforated drain
pe, with at least a four-inch diameter,shah be installed within the drainage materials. The drain pipe
must drain to a point of discharge,approved by Mason County.
Inspections
Prior to the c acement of concrete. the builder must schedule an inspection of the formwork and
reinforcement placement for the retaining wall footing. During the first inspection,the inspector will verify
the soil condition.footing dimensvons,foobrig reinforcement.and footrrg placement as well as the
provisions for drainage. At the next inspection,the inspector shal verify the wall d menwons and
reinforcement prior to the wall pour. A finai inspection mxrst be performed once al work is complete.
To schedule an inspection sail the Mason County 24-hour recorded inspection request iine at(360)427-
72432. Inspect)ons can also be requested online at: www.co.mason_nva_us or by fax at(360)427-7798_
141*n"uestrng an Y.Wett'on p4ease w rowae the tiailowmg inlbrmatron
1 i Name on permit 2)tape of inspection 3)Permit number
^i Site Address 5:1 Type of permit 6) Date inspectxxr requested and
Ti Fume and phone nun*- r of caller.
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GEOTECHNICAL 1UTING ]LABORATORY
RECOMMENDATIONS FOR RETAINING WALL ALTERNATIVES
Typically, block wall systems are more cost effective for long-term walls than the other options. Specific design
criteria for these options can be provided at your request by the block manufacturers.
RECOMMENDATIONS FOR SITE DRAINAGE
All ground surfaces, pavements and sidewalks should be sloped away from the residence and associated
structures. Surface water runoff should be controlled by a system of curbs, berms, drainage swales, and/or catch
basins and tight-lined into the appropriate drainage facilities We recommend that conventional roof drains be
installed. Footiniz drains shall be installed for the proposed structure. The roof drain should not be connected to
the footing d For footin&drains,the d ypical drainage
control measures are included on Figure 3. Onsite irrigation to lawn areas shall be closely monitored.
We recommend additional testing occur if infiltration is proposed at the project site. Either a double ring
�infiltrometer or a grain-size calculation will determine the permeability of the onsite material.
17.01.100E5(10) An analysis of both on-site and off-site impacts of the proposed
development.
SEPTIC IMPACT
The septic drainfield is located in the northwestern portion of the parcel on the southeastern side of Lake View
Place Drive. Chapter 246-272A-0210 of the Washington Administrative Code requires a minimal horizontal
separation between septic drain fields and various facilities including footing drains. The proposed drainfield will
be located over 50 feet from the proposed building location. We conclude the slope stability of the site will not
be adversely impacted by the proposed septic drainfield and the proposed septic drainfield will not adversely
impacted by the landslide hazard area. We also conclude proposed septic drainfield will not adversely impact the
proposed structures.
The proposed project will adversely impact neither the owner's site nor adjacent ones. See GENERAL below.
CONCLUSIONS AND RECOMMENDATIONS
GENERAL
Based on the results of our site reconnaissance, subsurface observations, and our experience in the area, it is our
opinion that the site is suitable for the proposed project. The proposed building locations are stable relative to
deep-seated instability and will not be affected by the proposed structures. The proposed structures will not
undermine adjacent slopes. Proper drainage control measures will reduce or eliminate the potential for erosion in
this area and improve slope stability.
Any potential hazards can be overcome in such a manner as to prevent harm to property and public health and
safety,and the project will cause no significant environmental impact for the life of the project.
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GEOTECHNICAL TESTING LABORATORY
If tested and confirmed, the onsite soils may be suitable for use as structural fill material. Saturated soil
conditions may be associated with these soils during or following extended periods of rainfall. However, to
reduce grading time and construction costs,we recommend that earthwork be undertaken during favorable weather
conditions.
Conventional construction equipment may be utilized for work at the site. Conventional spread footings may be
utilized at the site for support of the structure. We do recommend that roof and footing drains be installed for the
structure with conventional spread footings. A vapor barrier is recommended for all slab-on-grades. Conventional
spread and continuous wall footings appear to be the most suitable type of foundation for the support of the
proposed structure.
REPORT LIMITATIONS AND GUIDELINES FOR USE
We have prepared this report for the exclusive use of Michael Cofoni and his authorized agents for the proposed
single-family residence in Mason County, Washington. Site inspections, research, and mapping have culminated
in this report. This report is intended to meet the requirements of the Mason County Critical Areas Ordinance.
This report does not specify setbacks for: line-of-sight setbacks, FWHCA setbacks, eagle tree setbacks, wetland
setbacks, or property line setbacks. Within the limitations of scope, schedule and budget, our services have been
executed in accordance with generally accepted practices in the field of geotechnical engineering in this area at the
time this report was prepared. No warranty or other conditions,expressed or implied, should be understood.
CONTRACTORS ARE RESPONSIBLE FOR SITE SAFETY ON THEIR OWN CONSTRUCTION PROJECTS
Our geotechnical recommendations are not intended to direct the contractor's procedures, methods, schedule or
management of the work site. The contractor is solely responsible for job site safety and for managing
construction operations to minimize risks to onsite personnel and to adjacent properties.
READ THESE PROVISIONS CLOSELY
Some clients, design professionals, and contractors may not recognize that the geoscience practices (geotechnical
engineering or geology) are far less exact than other engineering and natural science disciplines. This lack of
understanding can create unrealistic expectations that could lead to disappointments, claims and disputes.
Geotechnical Testing Laboratory includes these explanatory"limitations" provisions in our reports to help reduce
such risks. Please confer with Geotechnical Testing Laboratory if you are unclear how these "Report Limitations
and Guidelines for Use"apply to your project or site.
GEOTECHNICAL,GEOLOGIC,AND ENVIRONMENTAL REPORTS SHOULD NOT BE INTERCHANGED
The equipment, techniques and personnel used to perform an environmental study differ significantly from those
used to perform a geotechnical or geologic study and vice versa. For that reason, geotechnical engineering or
geologic reporting does not usually relate any environmental findings, conclusions or recommendations; e.g.,
about the likelihood of encountering underground storage tanks or regulated contaminants. Similarly,
environmental reports are not used to address geotechnical or geologic concerns regarding a specific project.
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REFERENCES
MAPS
DeLorme 3-D TopoQuads(2002),Source Data USGS,Yarmouth,Maine.
Dragovich, Logan, Walsh, and Schasse(2002), Geological Map of Washington—Northwest Quadrant(Geological Map GM-
50),published by Washington State Department of Natural Resources.
Noble and Molenaar (1970), Geologic Map of Southeastern Mason County, Washington, Water Supply Bulletin 29, Plate 1,
Published by Washington State Department of Water Resources
Palmer, Magsino, Poelstra, Bilderback, Folger, and Niggemann (September 2004), The Liquefaction Susceptibility Map of
Mason County, Washington, published by Washington State Department of Natural Resources.
Palmer, Magsino, Bilderback, Poelstra, Folger, and Niggemann (September 2004), The Site Class Map of Mason County,
Washington,published by Washington State Department of Natural Resources.
Rogers, A. M., Walsh, T. J., Kockelman, W. J., and Priest, G. R. (1996), Map showing known or suspected faults with
quaternary displacement in the Pacific Northwest, published by U.S. Geological Survey OFR 91441-0, Plate 1,
scale 1:2,000,000.
Smith, Carson (1977), Relative Slope Stability of the Southern Hood Canal Area, Washington, prepared in cooperation with
the Washington Department of Natural Resources Division of Geology and Earth Resources; and, Department of the
Interior United States Geological Survey.
Dragovich, Logan, Walsh, and Schasse (2002), Geological Map of Washington—Northwest Quadrant(Geological Map GM-
50),published by Washington State Department of Natural Resources.
Walsh(1997), The Canyon River fault, an active fault in the southern Olympic Range, Washington: Washington Geology, v.
25,no.4,p.21-24,published by U.S.Geological Survey.
Washington State Department of Ecology (1979), Coastal Zone Atlas of Washington, Volume 9, published by Washington
State Department of Ecology.
PUBLICATIONS
Ambrose(1981),Simplified Design of Building Foundations,Table 2.5,pages 48-57,published by John Wiley&Sons, Inc.
ASTM International(2005),Annual Book of Standards 2005, Section 4, Volume 4.08,published by ASTM International,West
Conshohocken,Pennsylvania.
Bloom(1991),Geomorphology,published by Prentice-Hall,Inc.,Upper Saddle River,New Jersey.
Gallagher, Patricia M. (October 27, 2000), Passive Site Remediation for Mitigation of Liquefaction Risk, Dissertation
submitted to the Faculty of the Virginia Polytechnic Institute and State University,Virginia.
International Code Council,Inc.(2004),2003 International Building Code,published by International Code Council,Inc.
International Code Council,Inc.(2006),2006 International Building Code,published by International Code Council,Inc.
#08-0103 10011 Blomberg Street SW,Olympia,WA 98512 25
Phone#: (360)754-4612 Fax#: (360)754-4848
Kollmorgen Instruments Corporation (1994), Munsell Soil Color Charts (1994 Revised Edition), published by Macbeth
Division of Kollmorgen Instruments Corporation,New Windsor,New York.
McCarthy(1993), Essentials of Soil Mechanics and Foundations, published by Prentice-Hall, Inc., Upper Saddle River,New
Jersey.
Moffat(1992),Surveying 9`h Edition,published by Harper Collins,New York,New York.
Ness,Fowler,Parvin(1960),The Soil Survey of Mason County, Washington, USDA Soil Conservation Service, in cooperation
with the United States Department of Agriculture, and Washington Agricultural Experimental Station, and the Soils
Conservation Service.
Parks, Neal, Koloski, Laprade, Molinari, Butler, and Lorentson (November 2006), Guidelines for Preparing Engineering
Geology Reports in Washington, published by Washington State Geologist Licensing Board,Olympia,Washington.
Prakash(1981),Soil Dynamics,Figure 6.3,page 173,published by McGraw-Hill,Inc.
Sowers(1979),Introductory Soil Mechanics and Foundations: Geotechnical Engineering, Table 10:4,page 472,published by
Macmillan Publishing Co.,Inc.
Washington State Department of Transportation (WSDOT) (2005),Standard Specifications for Road, Bridge, and Municipal
Construction 2006 M41-10,prepared by WSDOT Engineering Publications,P.O.Box 47408,Olympia,Washington.
WEBSITES
Mason County Government Information Services
(http://www.co.mason.wa.us)
Mason County Codes,Ordinances,and Regulations
(http://www.co.mason.wa.us/code)
Puget Sound Lidar Consortium
(http://pugetsoundlidar.ess.washington.edu/lidardata/index.html)
Slope Stabilization Erosion Control Using Vegetation A Manual of Practice for Coastal Bluff
(http://www.ecy.wa.govibiblio/9330.htmi)
Vegetation Management Guide for Puget Sound Bluff Property Owners
(http://www.ecy.wa.gov/biblio/9331.html)
United States Department of Agriculture Natural Resource Conservation Service
(http://soildatamart.nres.usda.gov)
Washington Administrative Code
(http://apps.leg.wa.gov/wac/)
Washington Department of Ecology
(http://apps.ecy.wa.gov/welllog)
(https:Hfortress.wa.gov/ecy/coastalatlas/viewer.htm)
#08-0103 10011 Blomberg Street SW,Olympia, WA 98512 26
Phone#: (360)754-4612 Fax#: (360) 754-4848
GE®TECHNICAL TESTING LABORATORY
APPENDIX
#08-0103 10011 Blomberg Street SW,Olympia, WA 98512 27
Phone#: (360)754-4612 Fax#: (360)754-4848
f �
GEO TECHNICAL TESTING LAnoRATORY
BORING LOG
Date:d41;-X96 file'�: .20-0b&
Boriaglo-its tl. Chew: Na-hulcomntri.
Boring17w:h1vuvatStem suer Depch Drilled:
D_}.rh Lat Chaff i:V:mil 'Lrnl; Dnffim.
:iVic; Drscti}tioa inSeds• %M N Q„ �MLL F'L 1'i{ 34* rit =�1I� Camm�ata.
Pact&R.-mme h 8taca smd w Ger;4
g iilt;l et :5% 59 86 0% 63.C% -'I-C s 5C 8iuws 5mr-t&,>�
5
9•+
?l� S rJiwBw�Geed 7-M. 59 78."7% 51.0% 110% 5C Blass iar 5
Ila
!13
F.rrr De atng
l& >rmut-2=0satS m=±r
1`•
11f
1�
5C 5-9 Btmm-s for 4-5 hm&w
'tl
r'
:EBLa ssdrs ra_:
6'
3
' . �C cCBig�5��s
31
3<
3.3 IWO
f-Z Slaws c'®r 4�'f�2�w
38
A
tul
4%T B(mtisg 5cr<!
Grmen%i.water taNle-not aarountazi
#08-0103 10011 Blomberg Street SW,Olympia, WA 98512 28
Phone#: (360) 754-4612 Fax#: (360) 754-4848
GEOTECHNICAL TESTING LAs0RAT01tY
LABORATORY RESULTS
U-s-stnv_�'SL-.,-q Qp xE in lrxj*s U-S.sun_%wd sL^'z-Nimik.VY
-------------------------------------------
---------------- -------- ------ s ------------------- 20%
Tx
----------- 30%
T s
41D%
----------------- ------------------------------- 5M
---------- ------------------------- ---------
V
------------------------------------------------------------- ------------------------------------
------ --------------------- K4%
---------------------------------------------------------------------- - -------------- -I S
-+--------------------
------------------------- ------------
-------- ------------------------------- ----------------- ------- 90%
10 MCI
Grain Size in Millmelets
&Mas Sill: Claw
C-aw. Ftw. Q-rw. I 1�=&._ I I
rhtt: .499099 clumdfimews %CZXqA
larav4ew. 4:75 sl W.12tuL with Gunrg 36.95%
laftwe M.. spells-d- %&Md
losmir. F_- I Cr=6.u Nc 41.51%
".7m &Cl
. vet: cor-Mv C__ 166.99 't.lkistu-!".j%. I& zy
LiqwbiUmit__9.09, lixt FAtiz--: 21.
PlatkLincit-9.99 lawrJuer 11!eft 392cs
uwh. :5 F"M ?tvAixitvhv1W&--CIO Yes
Uosrse Actwl bdeWdatvi Films
Sec woo C try=C.v;usaJati�e e..t............. sect im cumazti'm
....... .....
As liar us ..
.......M .. .M ......
'N Z3W 55.9% SIM.10
amm *16 zoo 54.4%
4N C.U-41 56.0c accc% 46.1% 1
1.75" 445.66' aw.m. 6I.M1 4P.4% VA.%
444.0%
1.25 315C zw_`c 0.3M 44.3% 4 1.P.,.
250,ler 25.90 100.6% IMM 0.
3*' 19.96 94.2% W.2%
4190 0.1m, 30.9%, 3C..9%
16"
54.5% *144 1 0.166 E 25.44°1iw
I IZ54 V.4% 924% �170 I O.M 233%
kno
639. fty% 0.653
Copyright!Spears Engineering&Technical Service.PS,1336-2004 1
#08-0103 10011 Blomberg Street SW,Olympia, WA 98512 29
Phone#: (360)754-4612 Fax#: (360)754-4848
GEOTECHNICAL TESTING LABORATORY
-y' i5 20 30 to w 100 2M
-------------- --------
-------- r r
20%
terM. ------------------ ------ 30%.
T .
49%
-----—-—--—--------—-------- -----------—---4
------------------------------------------—-----------—------— --------—---—-—------------------ 60%
CL
-----------------4-—-—-----------
2V% ----—----------------—---------- —--------—
- - -------- —---------------
-----------------------------------------t-------------- -------------- ------------------ gn
A VIP is b 0
IM, 10 1 5.1 PD1 0.0m
Gryin Size in Millimetems
CwAks; 6M.J.. I SMI-111 U&N-S
C0%r-,4 rW COWA
la.moe-- 4r.* r6=41.31 L71-S 1.�kzcdv lubi.=ith Mt ini Gm� 41.97-1-
lwamfrl�M-. nk- 5. speciff—tious %IM:1.
ktmw. H..1 Ct-0.25 1pau
?'mjqct: Cv.,vw C:r-al.'s' Mvist3r:5.:'N
Client: CUA—M. Lia-xii Limit--COV hat Fafiu—
=tllz Li vit--CM F%%mm lhy"hs
DWk- N Fact ?tasticitv 61.06 4.11 Yes
Loarse -Axnal ::5fftavuw--z saes _ ::1. a-mTCw--z
.....s....e..c.dou..... w :Czo-slati'm section Cwtv_:Cun'wi -
Vic....I.......... . ...... ..... ............. .. ............... "....... ....":....... .....
Mofir )�f ?Mkr NILDL MM us yak rk: NIM MM
5UN
4,"ge, 'J".99' RNA% 4 2.366, 50.3% 59.-,%
16c.6% *16, 2.06C, 44,M
zklf 1.190 443% 44.5%.
Tv X.a MR%
39.2% 39.2%.46A
C425 33.7%C.-M, MM 2P.2%31.2
0.2% 1 93.3% 0.259,
40 n.2% *9C GAW 2&9%
4" Aft. 71.7% 7 1.7 TIl44 us, RZ.7% lu%
s.r a*,w 7,% *14C CAN 14.n.
12" U f% 74.4% 74.4% 4171Q' 1 OAK 1 123%,
3,r im is.4% is,-ma QUI WAS U.C% 11.61%
IV cm &to
Copyright;Spews Engineering&Technicol Services PS.1336-2004
408-0103 10011 Blomberg Street SW,Olympia, WA 98512 30
Phone#: (360)754-4612 Fax#: (360)754-4848
GEOTECHNICAL TESTING LABORATORY
SHEAR RESULTS
Freak Shear Stress vs. Normal Stress
3¢mr ------- -----
?5f:r
Shear=36'
rya;
c
Y
I X[
I
FV�
v�r'IIC.SiVn
=200 psf
Normal Stress tpsQ
#08-0103 10011 Blomberg Street SW, Olympia, WA 98512 31
Phone#: (360) 754-4612 Fax#: (360) 754-4848
GEOTECHNICAL TESTING UnoRAvropty
WELL LOG
V A T A I V 9 L L R 9 P 0 1 T Start Card No. 9 044173
0 Uniqae Veil I.D. I ABDI44
CL STAN OF VASNINGTON Water Right Permit No. GI-11431 C
(1) OWNER: Nan COLLINS LAIR COMMUNITY CL Address PO 101 141 ULPAII, VA 11519-
4) �Ij LOCATION OF MILL: County NASOX - 11 114 SV 1/4 Sec 31 T 23 N., 1 11 VN
3: .!&) STREET ADDRESS OF MILL (or nearest address) LOT Of Mulls U11, IRILFAII
.0 (3) PROPOSED USE: GM DOMISTIC 110) NEU LOG
i
.....................
4� ----------------------------------------------------------------
(4) TYPR OF VORI: Ovaer's Number of well Formation- Describe by color character, size or material
It sore and strocture, a Show Lbic is of aq I ifers and the kind
0 than
h:dn material
1911 MILL iethod: All 10TARi and nature at I te &I in each vtr.1tNenetr4ted' with
0 at [east one entry for each change in formation.
(3) DINRNSIONS: Diameter of veil 9 inches -----------------------------------------------------------------
Drilled 197 fL. Depth of completed veil III ft. I NATRAIAL FROM TO
HN STICK-UP
E I
b— FILL 1 113
Calift installed: a • Bit. frog 0 t. to ASIA ft. SIDON SAM CLAY 4 GRAVEL WORD Dia. from R. to ft. I MAY ARM SAM & CLAY GRAVEL i IS 174
C • Die. tros ft. to ft. I 111110111 ME GAWK 1ST3
03
W ---*---- --------------------*------- ------------------ DOW SAID GRAVEL I CLAY
Perforations: ROBINS IAA(RAVIL I CLAY SANDY
Tje of perforator used STAR PIRMTOR SAND GRAVEL A CLAY
1 0
S t perforations in. SAM(MAVIL I VATU LIPIRS OP MAY 111 its
0 11 perforations trot iff, ft. 11101111 CLAY It?
3 148
V 13: perforations from III ft. to 171 it. CLAY SMAKS/11AM SAM
perforations from it. to it. I IS01I GI.AVU SAID 1141 I Ift
..........................................................1 lI014f GRAVEL SAM SOME CLAY I Ito I It?
to Screens: NO I 111101111 GRAVEL SAM 1117 I its
Manufacturer's Name I Ml(RATU SAN VIT I Its I III
Type Model No. MO CLAY GRAVEL I SAM III its
Dist.
slot site from ft. to it. GRAIIII, SAID UTUILD 144
Diam. #lot size frog ft. to ft. Ml SAM GRAVII, lim 144 261
---------------------------------------------------- 111101111 QKAVU SAM I CLAY LATIAS Of 121l I Is?
A Gravel packed: RD Size offravel Ml SAM GRAVEL VATU 191
Gravel placed from it. to
------------- -----------------------------------------
Surface Fell: YIS To what depth? It It.
Material used in seal DOMITR
Did an rate contain unusable water? NO
Type of strata Depth of strata ft. C=3
Method of sealing strata off
0 M
--------------------
...............
(7) PUMP: Manufacturer's Name 7 r")
Z Type R.P.
-----------
C (2) VATU LEVELS: Land-rarface cleviiio'n
I bove mean sea level $So+ It,
Static level 141.1 ft. below top of well
11113/13
Artesian Pressure tbs. per square inch Date
0 Artesian water controlled by
11 Vork started 11116/15 Completed 11�03/15
0
(0) TELL TESTS: Drsvdown is amount water level is lowered belos MILL CONSTRUCTOR CERTIFICATION:
ILU static level. I constructed ad/or accept responsibility for con-
46 vas ia:pvr test mile? 79S It,yes,.bjrvhom1 I&I etrietion of this well, and its c te with all
Yield: 4 .1 cal./min with I I- I avilows after I bra. Vathijiftea vell'conitractiob standards. Materials used
41 91W the inforviatio reported Above are true to my best
C n
W 114 knowledge tad belief.e
E Itecowde
Timer, Va':, Level Time eater Level Time eater Level RAIR NICIK1101 DRILLING INC
143.1 1 343.1 Is 1437 (Person, firm, or corporatioal (Type or print)
CL 30 143.4 so 143.1 is 143.1
106 243.0 ADDRESS� DOI 113
Date or test 11113106
Basler test a ft, drawdown after hrs. IGM License No. 0619
A feet
It gal%1.1ft.
Air e f In W/ stem set at ft for kri. Contra r .
Artesian low -p.m. Date I bli.tr.Liiin No.
11
Temperature of water If Val a chemical analysis made? TIS 1, 1137011 Date 13/13/96
#08-0103 100 11 Blomberg Street SW, Olympia, WA 98512 32
Phone#: (360) 754-4612 Fax#: (360) 754-4848
FIGURE 1 VICINITY MAP
.�ff
I %
A tr
■ :� � � � vah� ��te C
_ f r
Callins.Lak: r_ !
■
1
XD TlopoQuatis cop liol,s M0 DeLorwe Ynm%outL.\D WN Sot¢ce Data:rSG 150 iY Scale:1:64.0 Detail:Ktio Da w,A('�94
#08-0103 10011 Blomberg Street SW, Olympia, WA 98512 33
Phone#: (360)754-4612 Fax#: (360)754-4848
DATUM FOR THE SITE PLAN INCORPORA UOUS TECHNIQUES AND SOURCES FILTER FABRIC MATERIAL BY WIDE ROLLS
INCLUDING THE FOLLOWING- FAeR1CTOVA3RE WIRE RING TO ATTACH Geotechnical
TAPING AND PACING,SLOPE MEASUREMENTS WITH AN IN TER,ANGLES AND 2'%7%140AU3E WIRE
BEARINGS USING A BRUNPON@ GEO TRANSIT,SITE LOCATIONS US IN®HAND FABRIC OR EQUIVALENT Testing
HELD GPS UNIT,TOPOGRAPHIC MAPS FROM DELORMEO,MASON COUNTY G.I.S. 1 e�7t�n
THIS IS NOT AN ACTUAL SURVEY 2°
5d FACE „<, Laboratory
P N COLLINS 2SMAX
AKE DR °
2'X4'WOOD POSTS,STANDARD OR BURY BOTTOM OF FILTER
^6 EEL EQUAL
POSTSLTERWITE: MATERALINB X12 TRENCH
STEEL FENCE
o I
Q g t FILTER FABRIC 8"
CR 4 GAUGE"REFABRIC
FABRIC OR EQUIVALENT
GROUNDURFACE 5 S4T
�`l A� PROVIDE 314.1 117 WASHED
--J GRAVEL BACKFILL IN TRENCH I7
AND ON BOTH SIDES OF FILTER
PR OSED FENCE FABRIC ON THE SURFACE 8'MIN
%
YX4'W000 POSTS
SEPT ALT STEEL FENCE POSTS
Geotechnical Services
V� DRAIN IELD FB TER FABRIC FENCE NOTES: QA/QC Services
1.FILTER FABRIC SHALL BE PURCHASED IN A CONTINUOUS ROLL CUT TO
THE LENGTH OF THE BARRIER TO AVOID USE OF JOINTS.MEN JOINTS Testing Services
ARE NECESSARY,FILTER CLOTH SHALL BE SPLICED TOGETHER ONLY AT
A SUPPORT POST WITH A MINIMUM&INCH OVERLAP AND SECURELY
FASTENED AT BOTH ENDS TO THE POST.
2.POSTS SHALL BE SPACED A MAXIMUM OF 8 FEET APART AND DRIVEN
SECURELY INTO THE GROUND(MINIMUM OF 30INCHES).
3.A TRENCH SHALL BE EXCAVATED APPROXB.IATELY8 INCHES WIDE AND 12 10011 Blomberg St.SW
INCHES DEEP ALONG THE LINE OF POSTS AND UPSLOPE FROM THE BARRIER. Olympia,WA 98512
Qgt 4.WHEN STANDARD STRENGTH FILTER FABRIC IS USED,A WIRE MESH Phone:(360)754-4612
LI �' SUPPORT FENCE SHALL BE FASTENED SECURELY TO THE UPSLOPE SIDE
NORTTT / OF THE POSTS USING HEAVY-DUTY WIRE STAPLES AT LEAST I INCH Fax:(360)754-4848
LONG,TIE WIRES OR HOG RINGS.THE WIRE SHALL EXTEND INTO THE
SCALE 1"=40' _ __-- TRENCH A MINIMUM OF 4INCHES AND SHALL NOT EXTEND MORE THAN 38
C.I.'5' INCHES ABOVE THE ORIGINAL GROUND SURFACE.
5.THE STANDARD STRENGTH FILTER FABRIC SMALL BE STAPLED OR WIRED Date: 04/16/2008
TO THE FENCE AND 201NCHES OF FABRIC SHALL BE EXTENDED
0 10 20 30 40 INTO THE TRENCH.THEFABRICSHALLNOTEXTENDMORETHAN3B Designed by: PL
INCHES ABOVE THE ORIGINAL GROUND SURFACE.FILTER FABRIC SHALL
O� NOT BE STAPLED TO THE EXISTING TREES. Drawn by: PL
_ P 8 WHEN EX RASTRENGTH FILTER FABRIC AND CLOSER POST SPACING IS Checked by: CDC
I� USED,THE WIRE MESH SUPPORT FENCE IMP BE ELIMINATED,IN SUCH
` 01NG A CASE,THE FILTER FABRIC IS STAPLED OR WIRED DIRECTLY TO THE Dwg#:04-16-08-024
I POSTS WASH ALL OTHER PROVISIONS OR ABOVE NOTES APPLYING.
1 - `1O� 7 AREA HAS BEEN PEERRMANES ENTLY STASIUZM.T BE REMOVED BEFORE THE UPSLOPE
LpVVV FILTER FABRIC FENCES SHALL BE INSPECTED IMMEDIATELY AFTER EACH
RAINFALL AND AT LEAST DAILY DURING PROLONGED RAINFALL.ANY
Q
REQUIRED REPAIRS SHALL BE MADE IMMEDIATELY.
tJ
sr�
GENERAL ER08ION CONTROL NOTES:T FFNcF / 1 EROSION CONTROL MEASURES SHALL BE IN PUCE PRIOR TO THE
BEGIN MNG OF CONSTRUCTION.THE PROJECT ENGINEER AND THE COUNTY
/ SHALL INSPECT AND APPROVE THE INSTALLATION OF
EROSION CONTROL MEASURES PRIOR TO BEGINNING CONSTRUCTION.
'- / 2.EROSION CONTROL MEASURES ARE NOT POISED TO THE ITEMS
N THIS PLAN.THE CONTRACTOR 1S RESPONSIBLE FOR THE INSTALUTION AND MAINTAINANCE OF ALL EROSION CONTROL MEASURES.
NO SILTATION OF EXISTING OR PROPOSED DRAINAGE FACILITIES
gt $
HALL BE ALLOWED.CARE SHALL BE TAKEN TO PREVENT MIGRATION PROJECT NAME:
OF SILTS TO OFF SITE PROPERTIES.
3.THE CONTRACTOR SHALL MAKE DAILY SURVEILLANCE OF ALL EROSION COFONI SITE
CONTROL MEASURES AND MAKE ANY NECESSARY REPAIRS OR ADDITIONS
Qgt TO THE EROSION CONTROL MEASURES.THE CONTRACTOR SHALL PROVIDE 681 NE COLLINS LAKE DRIVE
ADDITIONAL EROSION CONTROL MEASURES AS DETERMINED NECESSARY
BY OUN THE CTY INSPECTOR ANDOR THE PROJECT ENGINEER.FAILURE TAHUYA,WASHINGTON
TO COMPLY WITH ALL LOCAL AND STATE EROSION CONTROL
REQUIREMENTS MAY RESULT IN CIVIL PENALTIES BEING LEVIED PARCEL 223315000005
AGAINST THE CONTRACTOR AND/OR PROJECT OWNER.
4.DURING THE WET SEASON(NOVEMBER TO MARCH)ALL DISTURBED SOILS
SHALL BE STABILIZED WITHIN 48 HOURS AFTER STOP OF WORK EROSION op CONTROL MEASURES SHALL INCLUDE,BUT NOT BE LIMITED TO, I�pVI�I�I II I�,
60, COVERING THE EFFECTED AREA INCLUDING SPOIL PILES WASH
PLASTIC SHEETING,STRAW MATTING,JUTE MATTING,STRAW MULCH,
K R OR WOOD CHIPS SEEDING OF THE DISTURBED AREAS SHALL TAKE PLACE AS HEATHER PERMITS.
5,ALL SEEDED OR SODDED AREAS SHALL BE CHECKED REGULARLY
TO MAKE SURE VEGETATIVE COVERAGE IS COMLETE.AREAS SHALL BE
A P�ER REPAIRED,RESEEDED,AND FERTILIZED AS REQUIRED
N 8 TRACKINGOFO LOFFSITETRLLNOT BE ALLOWED.IFANY SOIL IS
,� TRACKED ONTOA COUNTY STREET,IT SHALL Ia REMOVED WILL
THE ENO
• OF THAT WORKING DAY.ANY FURTHER SOCKING V MUD WILL THEN
R N BE PREVENTED BY SWEEPING OR WASHING OF THE VEHICLES T RES
A BEFORE DUANG ON A COUNTY STREET.
R�1N 7 NO MORE THAN 500LF OF TRENCH ON
TgOpWIJSLOPEOFMORETHANS
O PERCENT SHALL BE OPENED AT ONE TIME
S.EXCAVATED MATERIAL SHALL BE PLACED ON THE UPHILL SIDE OF TRENCHES
NS �� 9 TRENCH DEWATERING TFLO FLOWING
STREAMS.
EAMS.BE MA GED DRAINAGE
SYSTEMS
OTHAT WILL
1 NOTADVERSELY AFFECT FLOWING STREAMS.DRAINAGE SY57EMS OR
OFFSITELL PROPERTIES.
GO 0 ALL STORM SEWER INLETS RECEIVING RUNOFF FROM THE PROJECT DURING SCALE:finch=40 feet
CONSTRUCTION SHALL BE PROTECTED 30 THAT SEDIMENT-LADENSTEM.WATER
WILL BE FILTERED BEFORE ENTERING THE CONVEYANCE SYSTEM.
11.ALL OFFSTTE CATCH BASINS IMMEDIATELY ADJACENT TO THE SITE
SHALL T PROTECTED FROM SILTATION. I ^ /^ /.�
72 ALL OWRBED AREAS SHALL BE SEEDED SPSODDED UPON COMPLETION /G K 2 OF W/OWL.THE CONTRACTOR DISTURBED
BE RESPONSIBLE TO ENSURE THAT
GROWTH E COVERAGE A THE DISTURBED AREAS 19 PROVIDEDd THAT
GROWTH
OF THE VEGETATION IS ESTABLISHED.
13 PLACED UNDER GRATETUANTIL VEGETOA O HIS ESTABLISHEDST SITE PLAN
1/2 INCH MINIMUM DIAMETER STEEL ROD
(STRAP)CLAMPED SECURELY TO PIPE
CORRUGATED TIGHTLINE 4 INCH
4"="` CO /M�N�iI� MINIMUM,6 INCH SUGGESTED
10
7%.
N
`ZV
W,
5�
1; K"V N.L.
TIGHTLINE ANCHORED WITH TWO,
3 FOOT REBAR LENGTHS OR BOLTS.
FLARE END SECTION
77
JLFU QUARRY SPALL
QUARRY Sp OR ENERGY
DISPERSION I SPERS'O'
ISPERSION DEVICE
GRASS-LINED SWALE SHOULD BE A
MINIMUM ONE FOOT WIDE AT THE
BOTTOM AND ONE FOOT DEEP WITH
A MAXIMUM SLOPE OF 5 PERCENT.
MINIMUM 4 FEET
LEVEL SECTION
GEOTEXTILE FABRIC
Geotechnical Testing Laboratory
Geotechnical Services 10011BI—bergSt.SW
01yrnpi.,WA 96512 FIGURE 3
QA/QC Services Phone:(360)754-4612
Testing Services F(360)754-4848 Not to scale DRAINAGE DETAILS
CROSS-SECTION A
(NORTH - SOUTH)
l
..................... .......................................... ................................................................................................................................................................ .................................................................
490 . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lu . . . . . . . . . . . . . . . _i z
.
480 . . . . . . . . . . . . . . . . . . . . . . . . . . :5
z
470 . .DRAIN. . PROPOSED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . .
Sin ot - - - bNO
BUILDING
Qg' T'O
460 . — AREA . . . . LOCATION
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25%SLOP��Qg.t
gt
Qgt Iwx' "
450 VEGETATED :
.............................................................................................. ...................... ................................................. [L_...................................................................
-SLOPE .0
440 . . . . . . . . . . . . . . �Qg . . . . EL . . . . . . . . . .
430
0 150 1100 1150 200 250 300
Geotechnical Testing Laboratory
Geotechnical Services 10011 Blomberg St.SW FIGURE 4
Oty.pia SCALE
QA/QC Services ,WA 98512
phone:(360)754-4612 1"=40' CROSS-SECTIONS
Testing Services Fax:(360)7544848