HomeMy WebLinkAboutGEO BLD2010-00130 - BLD Engineering / Geo-tech Reports - 2/1/2010 MASON COUNTY
DEPARTMENT OF COMMUNITY DEVELOPMENT
Planning Division
P 0 Box 279, Shelton, WA 98584
11910
(360)427-9670
Geotechnical ReportReview Acceptance Letter
March 30, 2010
STEVE JOHNSON. INC.
P.O. BOX 488
BELFAIR WA 98528
Case No.: GE02010-00011
Parcel No.: 12208511101-0 !
Proiect Description: GEO REPORT TO BUILD RESIDENCE
The Geotechnical Report for STEVE JOHNSON, INC. has been received and reviewed by the
Planning Department. The report was prepared by Staten dated 2/1/2010.
Based on the certification provided by the licensed engineer/geologist, the referenced
Geotechnical Report was prepared in general accordance with the requirements in the Mason
County Resource Ordinance, Landslide Hazard Areas 17.01.100.E.5. Mason County considers
the review valid until such time as scope of project, site conditions, and/or regulations change.
Should the scope of work, site conditions, and/or regulations change after the original review, then
an addendum from the original author of the report may be required to address these changes.
The report would only be re-reviewed if a permit for development were submitted after these
changes occur. Mason County does not certify the quality of the work done in this Geotechnical
Report.
Please contact me at (360) 427-9670, ext. 365 if you have questions.
Sincerely,
A2a�-Y-�
Allan Borden
Land Use Planner
Mason County Planning Department
Comments:
3/30/2010 Page 1 of 1 GE02010-00011
OK? ✓Comment: 021Vr L,
(e) Recommended setbackd fr41 the landslide hazard areas shoreline bluffs and the tops of
other pes on the propert
OK. V Comment: hoy
(8) Recommendations for the prepay ion 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.
OK? Comment:
(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 osion, landslides and harmful construction methods.
OK? Comment:
(10) An analysis 9f both on-site and off-site i pacts of the proposed development.
OK? ✓Comment: / �-
(11) Specifications of final developrh4t conditions such as, vegetative management, drainage,
erosion rol, and buffer widths.
co
OK? Comment:
(12) Recommendations for the preparation of structural mitigation or details of other proposed
mitigation. ^'
OK? Comment: /4
(13) A site map drawn to scale showing the property boundaries, scale, north arrow, and the location
and nature f existing and proposed developm nt on the site.
OK?Comment: -
Are the Documents signed and stamped? .
Type and #of License: P>E!n�J-P— 1+3 /� 3 Ot w
17
If not approved, what is the next action/recommendation for further action?
Reviewed by , on
Time spent in review:
SECOND REVIEW/UPDATE:
Reviewed by on
Time spent in second review:
THIRD REVIEW/ UPDATE:
Reviewed by , on
Time spent in third review:
Disclaimer: Mason County does not certify the quality of the work done in this Geological Assessment
Page 2 of 2 Form Effective June 2008
Mason County Department of Community Development
Submittal Checklist For a Geotechnical Report
instructions:
This checklist must be submitted with a Geotechnical Report and completed, signed, and stamped by the
licensed professional(s)who prepared the Geotechnical Report for review by Mason County pursuant to
the Mason County Resource Ordinance- If an item found to be not applicable, the report should explain
the basis for the conclusion. //
Applicant/Owner � ��� TQhnS?,r, /n c_ Parcel#
Site Address C-«rd ;, t I C'D L'rQ �(C+r r
(1) (a)A discussion of general geologic conditions in the vicinity of the proposed development,
Located on page(. ) (,
(b) A discussion of specific soil types
Located on page(s)
(c) A discussion of ground water conditions
Located on page(s)
(d) A discussion of the upslope geomorphology
Located on page(s) 3
(e) A discussion of the location of upland waterbodies and wetlands
Located on page(s) 3
(f) A discussion of history of landslide activity in the activity in the vicinity, as available in the
referenced maps and records
Located on page(s) //) l2
(2) A site plan which identifies the important development and geologic features.
Located on Map(s) �,7<e �'Ic- , 1,4
(3) Locations and logs of exploratory holes orprobes.
Located on Map(s)
�Ic �
(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.
Located on Map(s) 6�-,�
(5) A minimum of one cross section at a scale which adequately depicts the subsurface profile, and
which incorporates the details of roRo$ed grade changes.
Located on Maps) �ac, J Z.;{ , /� �.
(6) A description and results of slope stability analyses performed for both static and seismic loading
conditions.Analysts should examine worst case failures.The analysis should include the
Simplified Bishop's Method of Circles.The minimum static safety factor is 1.5, the minimum
seismic safety factor is 1A. and the quasi-static analysis coeffients should be a value of 0.15.
Located on page(s)
(7) (a) Appropriate restrictions on placement of drainage features
Located on page(s) /4-
(b) Appropriate restrictions on placement of septic drain fields
Located on page(s) /S
(c) Appropriate restrictions on placement of compacted fills and footings
Located on page(s) _7,
Page 1 of 2 Form Effective June 2008
Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report.
(d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other
slopes on the propert .
Located on page(s) /S
(e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of
other slopes on the property.
Located on page(s) /3
(8) Recommendations for the preparation of a detailed clearing and grading plan which specifically
identifies vegetation to be removed, a schedule for vegetation removal and replanting, and the
method of vegetation removal.
Located on page(s) AA
(9) Recommendations for the preparation of a detailed temporary erosion control plan which
identifies the specific mitigating measures to be implemented during construction to protect the
slope from erosion, landsloes and harmful construction methods.
Located on page(s) ,N A
(10) An analysis of both on-site and off-site impacts of the proposed development.
Located on page(s) /$
(11) Specifications of final development conditions such as, vegetative management, drainage,
erosion control, and buffer widths.
Located on page(s)
(12) Recommendations for the preparation of structural mitigation or details of other proposed
mitigation. /
Located on page(s) �I A
(13) A site map drawn to scale showing the property boundaries, scale,north arrow, and the location
and nature of existing and pro osed development on the site.
Located on Map(s) ��•4+ /L_ c:.) (A A
I, i C �� C �yc�r, �� t"n hereby certify under penalty of
perjury that I am a civil engineer licensed in the State of Washington with specialized knowledge of
geotechnical/geological engineering or a geologist or engineering geologist licensed in the State of
Washington with special knowledge of the local condiltkmis.I also certify that the Geotechnical
Report, dated )5� 4, �, 2 E/0 , and entitled
''Y J�I�nSo.� ��_ f ►�-�;�y 'e s,���r� meets au the requirements of the Mason
County Resource Ordinance,l.Andslide Hazard Section,is conVAete and file,that the assessment
demonstrates conclusively that the risks posed by the landslide hazard can be mitigated through the
included geotechnical design recommendations,and that all hazards are mitigated In such a manner as
to prevent harm to property and public health and safety.(Signature and Stamp)
Al CLYDt
G O�WAS/i� STI
�A FCISTERF'
�SS�ONALti�G`
Page 2 of 2 Form Effective.tune 2008
Disclaimer: Mason County does not certify the quality of the work done In this Geotechnical Report.
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Geotechnical Report
for
S. Johnson Single Family Residence
151
E Cardinal Court, Belfair
Parcel No. 12208 51 110TO /�,
Mason County, Washington
February 1, 2010
Project #1005
Prepared For:
Stephen Johnson, Inc. y CLYIbE
P.O. Box 488 P� sT
�L� WASy��c9)�
Belfair, Washington 98528 �P
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Prepared By:
,� 43045 O W�
Envirotech Engineering °.�� F("1STre'
74 NE Hurd Road SS�otvALEN�'
Belfair, Washington 98528
Phone: 360-275-9374
Fax: 360-275-4789
TABLE OF CONTENTS
1.0 INTRODUCTION...........................................................................................................................1
1.1 PROJECT INFORMATION............................................................................................................... 1
1.2 PURPOSE OF INVESTIGATION AND SCOPE OF WORK..................................................................... 1
2.0 SURFACE CONDITIONS..............................................................................................................3
2.1 GENERAL OBSERVATIONS............................................................................................................3
2.2 TOPOGRAPHY...............................................................................................................................3
2.2.1 Upslope Geomorphology and Water Bodies.......................................................................... 3
2.3 SURFACE DRAINAGE.....................................................................................................................3
2.4 SLOPE AND EROSION OBSERVATIONS...........................................................................................4
3.0 SUBSURFACE INVESTIGATION.................................................................................................5
3.1 FIELD METHODS,SAMPLING AND FIELD TESTING........................................................................ 5
3.2 GENERAL GEOLOGIC CONDITIONS...............................................................................................5
3.3 SPECIFIC SUBSURFACE CONDITIONS.............................................................................................6
3.3.1 Groundwater......................................................................................................................... 6
3.4 SOILS TESTING.............................................................................................................................6
4.0 ENGINEERING ANALYSES,CONCLUSIONS AND RECOMMENDATIONS.........................7
4.1 BUILDING FOUNDATION RECOMMENDATIONS..............................................................................7
4.1.1 Bearing Capacity.................................................................................................................. 7
4.1.2 Settlement............................................................................................................................. 7
4.1.3 Concrete Slabs-on-Grade...................................................................................................... 8
4.2 LATERAL EARTH PRESSURES........................................................................................................ 8
4.3 EARTHWORK CONSTRUCTION RECOMMENDATIONS ....................................................................9
4.3.I Excavation............................................................................................................................ 9
4.3.2 Placement and Compaction of Native Soils and Engineered Fill.......................................... 9
4.3.3 Retaining Wall Backfill...................................................................................................... 10
4.3.4 Wet Weather Considerations............................................................................................... 10
4.3.5 Building Pads...................................................................................................................... 11
4.4 SLOPE STABILITY....................................................................................................................... 11
4.4.1 Slope Stability Assessment and Analysis............................................................................. 13
4.4.2 Building and Footing Setbacks........................................................................................... 13
4.5 EROSION..................................................................................................................................... 14
4.5.1 Temporary Erosion Control................................................................................................ 14
4.5.2 Permanent Erosion Control................................................................................................ 14
4.6 SURFACE AND SUBSURFACE DRAINAGE...................................................................................... 14
4.6.1 Septic Drainfield Impacts.................................................................................................... 15
4.7 VEGETATION BUFFER AND CONSIDERATIONS............................................................................. 15
4.8 ON-SITE AND OFF-SITE IMPACTS............................................................................................... 15
4.9 SEISMIC CONSIDERATIONS AND LIQUEFACTION......................................................................... 15
4.9.1 Liquefaction........................................................................................................................ 16
5.0 CLOSURE..................................................................................................................................... 17
Appendix A- Site Plan
Appendix B-Geologic Map
Appendix C-Soil Information(Soil Profile; Soil Logs;Well Reports)
Appendix D-Slope Stability Input&Output
Appendix E—Erosion Control
Appendix F—Drainage Details
1.0 INTRODUCTION
Envirotech Engineering (Envirotech) has completed a geotechnical investigation for a single
family residential property located at 161 E Cardinal Court, identified as parcel number 12208 51
11010, Belfair, Washington (Project). The property is Lot 55 of the partially developed Belwood
Estates subdivision. As presented herein,this report includes information pertaining to the Project
in this Introduction Section; observations of the property and surrounding terrain in the Surface
Conditions Section; field methods and soil descriptions in the Subsurface Investigation Section;
and, conclusions/ recommendations for foundation, settlement, earthwork construction, lateral
earth pressures, slope stability, erosion control, drainage, vegetation, and seismic considerations
in the Engineering Conclusions and Recommendations Section.
An initial geotechnical evaluation of the Project was conducted by Envirotech without the
property owner, Stephen Johnson Inc., on January 26, 2010. It was determined that slopes in
excess of 40%with a vertical relief of at least 10 feet were present within 300 feet of the planned
development. Consequently, the proposed development will require a geotechnical report
pursuant to Landslide Hazard Areas of Mason County Resource Ordinance (MCRO) 17.01.100.
During the site visit by Envirotech, surface and subsurface conditions were assessed. After
completion of the field work and applicable Project research, Envirotech prepared this
geotechnical report in order to fulfill the MCRO.
1.1 Project Information
Information pertaining to the Project was provided by the proponent of the property during the
geotechnical investigation. Other information, such as site observations and assumed parameters
typical of this type of development were provided by Evirotech during the preparation of this
report.
The planned development consists of a 1- or 2-story single family residence, on-site septic
system, driveway and other ancillary features typical of this type of development. Foundation
construction is expected to consist of continuous strip footings with concrete slabs-on-grade or
stem walls. Approximate building footprint and other proposed features with relation to existing
site conditions are illustrated on the Site Map provided in Appendix A of this report.
1.2 Purpose of Investigation and Scope of Work
The purpose of this geotechnical investigation is to assess geological hazards, and evaluate the
Project in order to provide geotechnical recommendations that should be implemented during
development. The investigation included characterizing the general Project surface and
subsurface conditions, and evaluating the suitability of the soils to support the planned site
activities.
In order to fulfill the purpose of investigation, the geotechnical program completed for the
proposed improvements of the Project include:
• Review project information provided by the Project owner and/ or owner's
representative. This included a previous geotechnical study conducted by Geotechnical
testing Laboratory summarized in a report dated March 8, 2005;
Envirotech Engineering Johnson Geotechnical Report
74 NE Hurd Road page 1 161 E Cardinal Court,Belfair
Belfair,Washington 98528 Parcel 12208 51 11010
Ph. 360-275-9374 Mason County.Washington
Fax: 360-275-4789 February 1, 2010
• Conduct a site visit to document the site conditions that may influence the construction
and performance of the proposed improvements;
• Define general subsurface conditions of the site by observing subsoils within test pits
and/ or cut banks, review geological maps for the general area, research published
references concerning slope stability, and review water well reports from existing wells
near the Project;
• Collect bulk samples at various depths and locations;
• Perform soils testing to determine selected index and/or engineering properties of the site
soils;
• Complete an engineering analysis supported by the planned site alterations, and the
surface and subsurface conditions that were identified by the field investigation, soil
testing, and applicable project research; and,
• Establish conclusions based on findings, and make recommendations for foundations,
drainage, slope stability, erosion control, earthwork construction requirements, and other
considerations.
Envirotech Engineering Johnson Geotechnical Report
74 NE Hurd Road page 2 161 E Cardinal Court,Belfair
Belfair,Washington 98528 Parcel 12208 5111010
Ph 360-275-9374 Mason County,Washington
Fax: 360-275-4789 February 1,2010
2.0 SURFACE CONDITIONS
Information pertaining to the existing surface conditions for the Project was gathered on January
26, 2010 by Michael Staten, geotechnical engineer with Envirotech. During the site visit,the type
of geotechnical investigation was assessed, and site features were documented that may influence
construction and slope stability. This Surface Conditions Section provides information on general
observations, vegetation, topography, drainage and slope/ erosion conditions for the Project and
surrounding areas that may impact the Project.
2.1 General Observations
The property is accessed from East Cardinal Court, an existing paved roadway in Belfair,
Washington. The Project is currently undeveloped land with a graded driveway that is mostly
overgrown with vegetation. Cardinal Court terminates near the southwest corner of the property
line. Beyond the property, rural residential development exists. Vegetation on and near the
Project consists primarily of 2nd or 3`d growth firs, maples, madronas, scotch broom, and other
trees and shrubbery common to this area of the Pacific Northwest. An aerial photo of the Project
and immediate vicinity is provided on the following page.
2.2 Topography
The topographic information provided in this section was generally duplicated from the
aforementioned previous geotechnical investigation. Where necessary, slope verification included
measuring slope lengths and inclinations with a cloth tape and sextant. See the Site Map in
Appendix A and the Geological Map in Appendix B in this report for an illustration of general
topography with respect to the planned development.
From the anticipated building site, maximum descending grades is approximately 47% with a
vertical relief of approximately 14 feet. Other descending grades range from 5%to 45%.
2.2.1 Upslope Geomorphology and Water Bodies
Ascending grades are generally located to the northwest of the planned development.
This slope is relatively minor within 300 feet of the Project, with no apparent slope
grades of at least 15%. Additional geomorphology that is pertinent to both upslope and
downslope areas are provided in the Subsurface Investigation Section of this report.
There are no apparent water bodies or wetlands located upslope from the planned
development that would significantly influence the Project.
2.3 Surface Drainage
Stormwater runoff originating upslope from the anticipated development is expected to be
minimal to moderate. Runoff is mostly diverted away from the property due to the
accommodating terrain. Excessive scour, erosion or other indications of past drainage problems
were not observed within the immediate vicinity of the planned development.
Envirotech Engineering Johnson Geotechnical Report
74 NE Hurd Road page 3 161 E Cardinal Court,Belfair
Belfair,Washington 98528 Parcel 12208 51 11010
Ph. 360-275-9374 Mason County, Washington
Fax: 360-275-4789 February 1, 2010
2.4 Slope and Erosion Observations
The slope grades near the Project signal a potential landslide or erosion hazard area. Some
indicators that may suggest past slope movements include:
• Outwash of sediments near the bottom of the slope,
• Fissures, tension cracks, hummocky ground or stepped land masses on the face or top of
the slope, and parallel to the slope,
• Fine, saturated subsurface soils,
• Old landslide debris,
• Significant bowing or leaning trees,or,
• Slope sloughing or calving.
Significant mass wasting on the property or within the general vicinity of the Project were not
observed or discovered during research. Indications of past landslides, current unstable slopes,
deep-seated slope problems, or surficial slope failures were not observed during the site visit.
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Envirotech Engineering Johnson Geotechnical Report
74 NE Hurd Road page 4 161 E Cardinal Court,Belfair
Belfair,Washington 98528 Parcel 12208 51 11010
Ph. 360-275-9374 Mason County, Washington
Fax:360-275-4789 February 1,2010
3.0 SUBSURFACE INVESTIGATION
Information on subsurface conditions pertaining to the Project was primarily gathered on January
26, 2010 by Michael Staten, geotechnical engineer with Envirotech. Specific information on field
methods, sampling, field testing, general geologic conditions, specific subsurface conditions, and
results from soil testing are presented in this section of the report. Appendix C of this report
includes pertinent information on subsurface conditions for the Project, such as subsoil cross-
section(s),test pit log(s),and water well report(s). Applicable test pit locations are depicted on the
Site Plan and Geologic Map provided in the appendix of this report.
3.1 Field Methods, Sampling and Field Testing
Information on subsurface conditions for the Project was accomplished by examining soils within
test pits extending to depths of up to 4 feet below the existing ground surface, and observing cut
slopes of up to 4 feet within the vicinity of the property. Information on subsurface conditions
also included reviewing the previous geotechnical investigation conducted by Geotechnical
Testing Laboratories, reviewing geological maps representing the general vicinity of the project,
and water well reports originating from nearby properties.
One bulk sample was collected at the Project site at approximately 18 inches below the existing
ground surface near the anticipated building location. The soil sample collected was secured and
transported for possible laboratory testing.
Envirotech measured the relative density of the near-surface in-situ soils by gauging the
resistance of hand tools. Within testing locations, field testing results generally indicated medium
dense soils in the upper 24 inches,and dense soils from 24 inches to the depth of ternunous.
3.2 General Geologic Conditions
In general, soils at the project are composed of materials from glacial advances. The geologic
conditions as presented in the "Geologic Map of Washington," compiled by J. Eric Schuster,
2002 indicates Quaternary sediments, Qg. Quaternary sediments are generally unconsolidated
deposits, and dominantly deposited from glacial drift, including alluvium deposits. This project is
located within the Puget Lowland. Typically, "lower tertiary sedimentary rocks unconformably
overlie the Crescent Formation."as revealed in the Geologic Map. Initial sedimentary rocks were
formed from shales, sandstones and coal deposits from rivers. During the Quaternary period, the
Puget Lowland was covered by numerous ice sheets, with the most recent being the Fraser glacier
with a peak of approximately 14,000 years ago. Upon the glacial retreat, the landscape was
formed by glacial erosion glacial drift deposits.
According to the "Interactive Geologic Map, 1:100,000 Quadrangle," as depicted by the
Department of Natural Resources, this Project consists mostly of glacial till, Qg. Glacial Till is
usually described as "unsorted, unstratified, highly compacted mixture of clay, silt, sand, gravel,
and boulders deposited by glacial ice of the Puget lobe; gray; may contain interbedded stratified
silt, and gravel; sand-size fraction is very angular and contains abundant polycrystalline quartz,
which distinguishes this unit from alpine till;cobbles and boulders are commonly striated and(or)
faceted; although unweathered almost everywhere, may contain cobbles or small boulders of
deeply weathered granitic rock."
Envirotech Engineering Johnson Geotechnical Report
74 NE Hurd Road page 5 161 E Cardinal Court,Belfair
Belfair,Washington 98528 Parcel 12208 51 11010
Ph. 360-275-9374 Mason County,Washington
Fax: 360-275-4789 February 1, 2010
3.3 Specific Subsurface Conditions
The following subsurface conditions are estimated descriptions of the Project subgrade utilizing
information from the depth of penetration at all testing, sampling, observed and investigated
locations. Soils for this project were primarily described utilizing the Unified Soil Classification
System (USCS)and the Soil Conservation Service(SCS)descriptions.
The Project is composed of native soils with no indications of borrowed fill except for maybe
some sidecast due to driveway construction. For engineering purposes, these native soils consist
of distinguishable layers,as presented below.
Soils within the upper 4 feet of natural ground were observed to be moist, brown with some grey,
silty sand with gravel (SM)and few cobbles.
Soils below the upper 4 feet layer are expected to be similar to the overlying soils, except denser
and increasingly coarse with depth. This is based on nearby well reports, site geology, and/ or
knowledge of the general area.
The relative densities of the soil are provided above in Section 3.1. Expanded and specific
subsurface descriptions, other than what is provided in this section, are provided in the soil logs
located in Appendix C of this report.
According to the "Soil Survey of Mason County," by the United States Department of
Agriculture, Soil Conservation Service, the site soils are described as Everett Gravelly Sandy
Loam, Eg Ek with 5% - 15% slopes, and 15% to 30% slopes respectively. However, slopes
exceeding 30%were observed on the property.
3.3.1 Groundwater
From the water well report(s)and knowledge of the general area, permanent groundwater
is over 100 feet directly below the property at the building pad location. Perched
groundwater at shallow depths was not observed on-site, nor indicated on the well
reports.
3.4 Soils Testing
The soil samples obtained at the Project site during the field investigation were preserved and
transported for possible laboratory testing. Visual classification of soils was performed in the
field at all observed soil profiles. Visual classifications were performed in accordance with the
American Standards for Testing and Materials (ASTM D2488).
The general results from the visual classification are presented above in the Subsurface
Conditions Section. Specifically, soils within the upper 4 feet in one testing location consisted of
approximately 20% gravel, 65% sand-sized soils, and 15% silt with low plasticity. Minor
variations observed during the visual classification of particle size content (i.e. gravel, sand,
fines), or isolated pockets within the soil stratification were insignificant in relation to the overall
engineering properties of the soil.
Envirotech Engineering Johnson Geotechnical Report
74 NE Hurd Road page 6 161 E Cardinal Court,Belfair
Belfair,Washington 98528 Parcel 12208 51 11010
Ph. 360-275-9374 Mason County,Washington
Fax: 360-275-4789 February 1,2010
4.0 ENGINEERING ANALYSES,CONCLUSIONS AND RECOMMENDATIONS
The following sections present engineering analysis and recommendations for the proposed
improvements of the Project. These recommendations have been made available based on the
planned improvements as outlined in the Introduction Section of this report; general observations
including drainage and topography as recapitulated in the Surface Conditions Section; and, soil/
geologic conditions that were identified from the geotechnical investigation that is summarized in
the Subsurface Investigation Section. Engineering analysis and recommendations for the Project
that is provided herein, includes pertinent information for building foundations, earthwork
construction, slope stability, erosion control, drainage,vegetation and seismic considerations.
4.1 Building Foundation Recommendations
Recommendations provided in this section account for the site development of a typical one- or
two-story, single family residential structure. The recommended allowable bearing capacities and
settlements as presented below, consider the probable type of construction as well as the field
investigation results by implementing practical engineering judgment within published
engineering standards. Evaluations include classifying site soils based on observed field
conditions and soil testing for this Project. After deriving conservative relative densities, unit
weights and angles of internal friction of the in-situ soils, the Terzhagi ultimate bearing capacity
equation was utilized for determining foundation width and depth.
Stepped foundations are acceptable, if warranted for this Project. Continuous, isolated, or stepped
foundations shall be horizontally level between the bottom of the foundation and the top of the
bearing strata. The frost penetration depth is not expected to extend beyond 12 inches below the
ground surface for this Project under normal circumstances and anticipated design features. The
soils on-site have low to moderate frost susceptible characteristics and should be used only to the
extents provided in this report.
4.1.1 Bearing Capacity
Existing in-situ soils for this Project indicates that the structure can be established on
shallow, continuous or isolated footings. Foundations shall be established on relatively
undisturbed native soil. Alternatively, foundations may be constructed on selective re-
compacted native soil or compacted engineered fill as described in the Earthwork
Construction Recommendations Section of this report.
For a bearing capacity requirement of no more than 1500 psf, a minimum footing width
of 12 inches shall be placed at a minimum of 18 inches below the existing ground
surface. Isolated footings should be a minimum of 24 inches square or in diameter.
Foundation recommendations are made available based on adherence to the remaining
recommendations that are provided in this report. Alterations to the aforementioned
foundation recommendations may be completed upon a site inspection by a geotechnical
engineer after the foundation excavation is completed.
4.1.2 Settlement
Total and differential settlement that a structure will undergo depends primarily on the
Envirotech Engineering Johnson Geotechnical Report
74 NE Hurd Road page 7 161 E Cardinal Court,Belfair
Belfair,Washington 98528 Parcel 12208 51 11010
Ph. 360-275-9374 Mason County, Washington
Fax: 360-275-4789 February 1. 2010
_ subsurface conditions, type of structure, amount and duration of pressure exerted by the
structure, reduction of pore water pressure, and in some instances, the infiltration of free
moisture. Based on the expected native soil conditions, anticipated development, and
construction abides by the recommendations in this report, the assumed foundation
system may undergo a maximum of 1.0 inch total settlement, and a maximum differential
settlement of 0.75 inch.
4.1.3 Concrete Slabs-on-Grade
Interior slabs, if utilized, should be supported on a minimum of 4 inches of compacted
coarse, granular material (Passing U.S. Sieve #10 or greater) that is placed over
undisturbed native subgrade or engineered fill. Native soils found at the Project site may
be suitable for use as material directly beneath concrete slabs if it meets the aforesaid
requirements or screened to meet these requirements. The top 2 to 6 inches of native soil
should be removed prior to the placement and compaction of the aforementioned 4-inch
coarse, granular material.
The recommendations for interior concrete slabs-on-grade as presented herein are only
relevant for the geotechnical application of this Project. Although beyond the scope of
geotechnical engineering, concrete slabs should also be designed for structural integrity
and environmental reliability. This may include some type of vapor barrier or moisture
control for mitigating excessive moisture in the building.
4.2 Lateral Earth Pressures
Retaining walls may be utilized for this Project. The lateral earth pressures exerted through the
backfill of a retaining wall are dependent upon several factors including height of retained soil
behind the wall, type of soil that is retained, degree of backfill compaction, slope of backfill,
surcharges,hydrostatic pressures,earthquake pressures, and the direction and distance that the top
of the wall moves.
An equivalent fluid unit weight used for structural design may be estimated as the product of the
backfill soil unit weight and the earth pressure coefficient for at-rest pressures. Retaining walls
should be designed to resist a lateral earth pressure based on an equivalent fluid unit weight of 45
pounds per cubic foot (pcf) and 55 pcf for backfill consisting of engineered fill and native soils,
respectively. These values shall be increased by 1 pcf for every 1 degree of backfill/natural slope
angle. These equivalent fluid unit weight values do not include lateral earth pressures induced by
earthquakes or surcharges from live loads. See the Earthwork Construction Recommendations
Section for details concerning the use of native soils, engineered fill and placement of backfill.
Lateral earth pressure recommendations are based on active or at-rest earth pressures, and the
backfill conforming to the recommendations outlined in the Earthwork Construction
Recommendations Section of this report. For instances when it is necessary for the retained earth
to induce passive earth pressures, additional design parameters must be accounted for in the
retaining wall analysis. For theses cases, recommendations should only be provided by a qualified
engineer after the type of backfill is specified, and the final wall height is determined.
Envirotech Engineering Johnson Geotechnical Report
74 NE Hurd Road page 8 161 E Cardinal Court,Belfair
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1
4.3 Earthwork Construction Recommendations
Founding material for building foundations shall consist of undisturbed native soils. Compacted
engineered fill, or selective re-compacted native soils may be used to the extents provided in this
Earthwork Construction Recommendations Section. The following recommendations include
excavations, subgrade preparation,type of fill, and placement of fill for building foundations.
4.3.1 Excavation
Excavation is recommended to remove any excessive organic content or other deleterious
material, if present, beneath foundations and to achieve appropriate foundation depth.
Additional sub-excavation will be required for this Project if the soils below the required
foundation depth are loose, saturated, or otherwise incompetent due to inappropriate land
disturbing, or excessive water trapped within foundation excavations prior to foundation
construction. All soils below the bottom of the excavation shall be competent, and
relatively undisturbed or properly compacted fill. If these soils are disturbed or deemed
incompetent, re-compaction of these soils below the anticipated footing depth is
necessary. Excavations shall be completely dewatered, compacted, and suitable before
placement of additional native soil, engineered fill or structural concrete. It is suggested
that foundation excavations are inspected by a geotechnical engineer or qualified
professional in order to assess the bearing material prior to the placement of structural
footings.
4.3.2 Placement and Compaction of Native Soils and Engineered Fill
For engineered fill or disturbed native soils that will be utilized as fill material directly
beneath foundations, observation and/ or geotechnical testing is required prior to
foundation construction. The following placement and compaction requirements are
necessary.
For disturbed native soils or engineered fill beneath foundations, limits of compacted or
re-compacted fill shall extend laterally from the bottom edge of the foundation at a rate of
one foot for each foot of compacted or re-compacted fill beneath the foundation. See the
illustration below.
FOOTING
COMPACTED
NATIVE SOILS
OR ENGINEERED 1
FILL 1
I I UNDISTURBED SUBGRAW
Both engineered fill and native soils used as compacted fill should be free of roots and
other organics, rocks over 6 inches in size, or any other deleterious matter. Engineered
fill should consist of the following gradation:
Envirotech Engineering Johnson Geotechnical Report
74 NE Hurd Road page 9 161 E Cardinal Court,Belfair
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1
U.S.Standard Sieve % Finer(by weight)
6" 100
Y 60— 100
No. 4 20—60
No. 200 0 - 8
Table 1
Partical Size Distribution of Engineered Fill
Compaction shall be achieved in compacted lifts not to exceed 8 inches and 6 inches for
native soils and engineered fill, respectively. Each lift should be uniformly compacted to
at least 95% of the modified Proctor maximum dry density (ASTM D 1557) and within
3% of optimum moisture content. Each lift surface should be adequately maintained
during construction in order to achieve acceptable compaction and inter-lift bonding.
Temporary earth cuts and temporary fill slopes exceeding 4 feet in height should be
limited to a slope of 2:1 (horizontal:vertical). Utility trenches or other confined
excavations exceeding 4 feet should conform to OSHA safety regulations.
4.3.3 Retaining Wall Backfill
Native soils may be used as retaining wall backfill for this Project if the
recommendations below are followed. Backfill may also consist of engineered fill, as
presented in this report, or borrow material approved by a geotechnical engineer.
Compaction of these materials shall be achieved in compacted lifts of about 12 to 24
inches. Each lift should be uniformly compacted to no more than 90% of the modified
Proctor maximum dry density (ASTM D 1557). In addition, heavy construction
equipment should be at a distance of at least '/2 the wall height. Over-compaction and
limiting heavy construction equipment should be prevented to minimize the risk of excess
lateral earth pressure on the retaining structure. Envirotech recommends that retaining
wall backfill is compacted with light equipment such as a hand-held power tamper. If
clean, coarse gravel soils are utilized as engineered fill, and surcharges will not influence
the retaining wall, compaction may be achieved by reasonably densifying granular soils
with construction equipment.
Backfill for the retaining wall should extend vertically from the top of the footing to the
proposed ground surface. The backfill should also extend horizontally from the back of
the retaining wall to at least 2 feet. Perforated drain pipe for retaining walls should have a
minimum diameter of 4 inches and direct water to an appropriate infiltration or outfall as
recommended in the Surface and Subsurface Drainage Section of this report. Coarse,
clean gravel (1 inch diameter) is recommended to be placed at least 24 inches around the
drain pipe in order to provide increased drainage capabilities. Non-woven geotextile filter
fabric designed to impede fine particles should be wrapped around the aforementioned
coarse gravel for reducing the potential of silt migration and clogging of the drain pipe.
4.3.4 Wet Weather Considerations
Although the subsoil characteristics do not pose a great risk in regards to saturation,
Em-irotech Engineering Johnson Geotechnical Report
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additional provisions may be required during prolonged wet weather. Every precaution
should be made in order to prevent free moisture from saturating and ponding within
excavations. If the bottom of excavations used for footing placement changes from a
moist and dense characteristic as presented in this report to loose, saturated conditions,
then these soils become unsuitable for foundation bearing material. If this situation
occurs, a geotechnical engineer should be notified, or these soils should be completely
removed and replaced with suitable compacted material as presented above.
4.3.5 Building Pads
Building pads for this Project, if utilized, shall be constructed per the fill placement and
compaction recommendations as presented above. Both engineered fill and native soils
may be used for building pads. Building pad slopes shall be no steeper than 2:1 for both
compacted engineered fill and re-compacted native soils used as fill. Building pad fill
shall be "keyed"into the existing subgrade to a depth of at least 2 feet below the existing
ground surface. The term "keyed," as used here, implies that the interface between the
building pad and subgrade is horizontally level. Alternatively, building pads may be
keyed into the subgrade to the above specified depth, and stepped. Stepped fill should be
keyed into the subgrade at a minimum width of 10 feet. All footings shall be located at
least 5 feet away from the top of the engineered fill slope.
4.4 Slope Stability
Landslides are natural geologic processes, and structures near slopes possess an inherent risk of
adverse settlement, sliding or structural damage due to these processes. Geotechnical engineering
cannot eliminate these risks for any site with sloping grades because gravity is constantly
inducing strain on the sloping soil mass. Excessive wet weather and/ or earthquakes will
exacerbate these strains. Geotechnical engineering considers excessive wet weather and `design'
earthquakes in order to provide an acceptable factor of safety for developing on or near sloping
terrain for the current conditions. These factors of safeties are based on engineering standards
such as defining engineering properties of the soil, topography, water conditions, seismic
acceleration and surcharges.
Surface sloughing or other types of surficial slope movements usually do not affect the deep-
seated structural capability of the slope. However, excessive and/or repeated surficial slope
movements, if not repaired, may represent a threat to the structural integrity of the slope. If this
situation does arise, the slope shall be inspected by a geotechnical engineer. Subsequently,
maintenance may be required in order to prevent the possibility of further surficial or deep seated
slope movements that may be damaging to life and property.
According to the Coastal Zone Atlas of Mason County, Washington, the Project is within and
near terrain labeled `Stable' regarding potential landslide activity. Stable slopes are generally not
prone to landslides due to small grades and accommodating. However, this site is considered
inherently hazardous due the existing geology and/ or topography, and additional analyses and
recommendations concerning the slopes are presented herein. A Stability Map from the Coastal
Zone Atlas for the general area of this Project may be found on the following page of this report.
Envirotech Engineering Johnson Geotechnical Report
74 NE Hurd Road page 11 161 E Cardinal Court,Belfair
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Ph. 360-275-9374 Mason County, Washington
Fax: 360-275-4789 February 1, 2010
5� 1:24AM
fY• J��V
Project
l ,
Map from Washington State Department of Ecology Website
According to the Resource Map from the Washington State Department of Natural Resources
(DNR), the Project is not within terrain labeled `highly unstable' or `highly erodible' relating to
soils. In addition, DNR did not indicated previous landslide activity near the Project. DNR
labeled portions of this project as medium and high slope instability with relation to slopes. This
delineation is primarily dependent upon slopes and convergence. Secondly, lithology and
precipitation are modeled within this delineation. In summary, this designation is based on
mapping without field observations or knowledge of the specific site geology or soils. A
Resource Map from the DNR Forest Practices Application Review System is provided below:
------------
Project
17M60 i70 k
`N \
,me. 170/142 me
�� lPulol louts
srknL l...a
Resource Map from Washington State Department of Natural Resources Website
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74 NE Hurd Road page 12 161 E Cardinal Court,Belfair
Belfair,Washington 98528 Parcel 12208 5111010
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4.4.1 Slope Stability Assessment and Analysis
The Simplified Bishop Method, utilizing `STABLE' software, was used to analyze the
static stability of the site slopes. Seismic conditions were estimated utilizing worst case
scenario values from the static analysis,a quasi-static analysis coefficient of at least 0.15,
and applying the applicable values to STABLE software. Various radii's and center
points of the circle were automatically selected, and produced factor of safeties in a
graphical and tabular format. Worst case scenario values were used in the slope stability
analysis in regards to topography, surcharges, water content, internal friction and
cohesion of the site soils. STABLE software has been repeatedly checked with manual
calculations, and consistently proved to be a very conservative program. The following
soil properties were used in the analysis, and are based on observed conditions, known
geology,and/or published parameters:
• Soil unit weight: 135 pcf
• Angle of internal friction: 36 degrees
• Cohesion: 100 psf
Based on the slope stability analysis, a minimum factor of safety was determined to be
2.5 relative to static slope failures, and 1.5 with relation to seismic conditions. See the
slope stability information in Appendix D for a depiction of input parameters and
example of outputs.
Based on the slope delineations by both the Departments of Ecology and Natural
Resources, site investigation, and the results of the aforesaid slope stability analysis, it is
our opinion that the proposed development should occur in accordance with this
geotechnical report.
4.4.2 Building and Footing Setbacks
Provided that assumptions relating to construction occur and recommendations are
followed as presented in this report,the factor of safety for slope stability is sufficient for
a 25 feet footing setback from the face of the nearby descending slopes exceeding 40%.
See the figure below and the Geologic Map in Appendix B for an illustration of the
setbacks.
STRUCTURE
TOP OF
SLOPE SLOPE
FACE
I I—I I —I I
�— 25 FT MIN — FOOTING
The required setbacks may be reduced, if necessary, to no less than 10 feet if deeper
foundations or other design alternative is completed by the geotechnical engineer.
Envirotech Engineering Johnson Geotechnical Report
74 NE Hurd Road page 13 161 E Cardinal Court,Belfair
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4.5 Erosion
Based on the USCS description of the Project soils, the surface soils are considered moderately
erodible. Temporary and/ or permanent erosion control measures may be required for site
development. Extents of temporary erosion control will mostly depend on the timeliness of
construction,moisture content of the soil, and amount of rainfall during construction. Soil erosion
typical to the existing site conditions and planned disturbance of the Project include wind-borne
silts during dry weather, and sediment transport during prolonged wet weather. Sediment
transport could be from stormwater runoff or tracking off-site with construction equipment.
Erosion control measures may need to be employed if excessive erosion occurs or required by the
County or other prevailing agencies.
Sedimentation control should be adequate when utilizing the erosion control recommendations as
presented herein together with implementing appropriate erosion controls with the degree of care
as expected from a licensed contractor. Additional erosion control information and specifications
may be found in the appropriate "Stormwater Management Manual for Western Washington,"
prepared by the Washington State Department of Ecology Water Quality Program.
4.5.1 Temporary Erosion Control
Erosion control during construction should include minimizing the removal of vegetation
to the least extent possible. If necessary, erosion control measures during construction
may include stockpiling cleared vegetation, silt fencing, intercepting swales,berms, straw
bales, plastic cover or other standard controls. Silt fencing is presented in this report as
the first choice for temporary erosion control. Any erosion control should be located
down-slope and beyond the limits of construction and clearing of vegetation where
surface water is expected to flow. If the loss of sediments appears to be greater than
expected, or erosion control measures are not functioning as needed, additional measures
must be implemented immediately. See Appendix E for sketches and general notes
regarding selected erosion control measures. The Site Map in Appendix A depicts the
recommended locations for erosion control facilities to be installed.
4.5.2 Permanent Erosion Control
Permanent erosion control may also be necessary if substantial vegetation has not been
established within disturbed areas upon completion of the Project. Temporary erosion
control should remain in place until permanent erosion control has been established.
Permanent erosion control may include promoting the growth of vegetation within the
exposed areas by mulching, seeding or an equivalent measure. Selected recommendations
for permanent erosion control are provided in Appendix E. Additional erosion control
measures that should be performed include routine maintenance and replacement, when
necessary, of permanent erosion control, vegetation, drainage structures and/or features.
The following Surface and Subsurface Drainage Section may have additional
recommendations with relation to permanent erosion for surface drainage features.
4.6 Surface and Subsurface Drainage
Positive drainage should be provided in the final design for all planned residential buildings.
Envirotech Engineering Johnson Geotechnical Report
74 NE Hurd Road page 14 161 E Cardinal Court,Belfair
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Fax: 360-275-4789 February 1, 2010
Drainage shall include sloping the ground surface, driveways and sidewalks away from the
Project structures. All constructed surface and subsurface drains should be adequately maintained
during the life of the structure. If drainage problems occur during or after construction, additional
engineered water mitigation will be required. This may include a combination of swales, berms,
drain pipes, infiltration facilities, or outlet protection in order to divert water away from the
structures to an appropriate protected discharge area.
Both footing perimeter drains and roof drains are recommended for this Project. Subsurface water
intercepted in the footing perimeter drains, and stormwater collected from roof drains shall be
separately tight-lined to an appropriate infiltration location. Roof drains should be located within
the southern portion of the parcel. Recommended infiltration locations are delineated on the
Geologic Map in Appendix B, and drainage details are provided in Appendix F of this report.
4.6.1 Septic Drainfield Impacts
The approximate location of the proposed septic drainfield is presented on the Site Plan
in Appendix A of this report. Based on the septic drainfield location with relation to the
existing and proposed topography, the drainfields are not expected to adversely influence
the structures near the critical slopes. This is also based on compliance with the
recommendations in this report.
4.7 Vegetation Buffer and Considerations
Vegetation is an excellent measure to minimize surficial slope movements and erosion on slope
faces and exposed surfaces. By removing trees, the root strength is decreased over time, thereby
lowering the `apparent' cohesion of the soil. Transpiration is decreased, which results in
additional groundwater, increased pore water pressure and less cohesion/ friction of the soil
particles. Stormwater runoff also increases, and, fewer plants will create less absorption of the
force from raindrops,thereby creating the potential for erosion hazards.
Vegetation shall not be removed from the face of the steep slope or within a distance of 10 feet
beyond the top of the slope. However, any tree deemed hazardous to life or property shall be
removed. If tree removal is necessary, then stumps and roots shall remain in place, and the
underbrush and soil shall remain undisturbed as much as possible. Any disturbed soil shall be
graded and re-compacted in order to restore the terrain similar to preexisting conditions and
drainage patterns. See the Geologic Map in Appendix B of this report for a depiction of the
vegetation buffer.
4.8 On-Site and Off-Site Impacts
From a geotechnical position, it is Envirotech's opinion that the subject property and adjacent
properties to the proposed development should not be significantly impacted if all
recommendations in this report are followed. This is based on the expected site development,
existing topography, land cover,and the recommendations presented in this report.
4.9 Seismic Considerations and Liquefaction
Soils immediately below the expected foundation depth for this Project are generally Type D,
Envirotech Engineering Johnson Geotechnical Report
74 NE Hurd Road page 15 161 E Cardinal Court,Belfair
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Fax: 360-275-4789 February 1. 2010
corresponding to the International Building Code (IBC) soil profiles. According to the IBC, the
regional seismic zone is 3 for this Project. The estimated peak ground acceleration ranges from
0.50g to 0.60g. This estimation is based on the United States Geological Survey(USGS)National
Seismic Hazard Project in which there is an estimated 2% probability of exceedance within the
next 50 years.
There are no known faults beneath this Project. The nearest Class `A' or Class `B' fault to this
property is the Tacoma Fault Zone, in which is approximately 3 miles to the south of this Project.
This information is based on the USGS Quaternary Fault and Fold Database for the United States.
4.9.1 Liquefaction
The potential for liquefaction is believed to be low for this Project. This is based, in part,
on the subsurface conditions such as soil characteristics and the lack of a permanent
shallow water table. Subgrade characteristics that particularly contribute to problems
caused from liquefaction include submerged, confined, poorly-graded granular soils (i.e.
gravel, sand, silt). Although gravel-and silt-sized soil particles could be problematic, fine
and medium grained sands are typically subjected to these types of seismic hazards. No
significant saturated sand stratifications are anticipated to be within the upper 50 feet of
the subsoil for this Project.
Envirotech Engineering Johnson Geotechnical Report
74 NE Hurd Road page 16 161 E Cardinal Court,Belfair
Belfair,Washington 98528 Parcel 12208 51 11010
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Fax: 360-275-4789 February 1, 2010
5.0 CLOSURE
Based on the project information and site conditions as presented in this report, it is Envirotech's
opinion that additional geotechnical studies are not required to further evaluate this Project.
Due to the inherent natural variations of the soil stratification and the nature of the geotechnical
subsurface exploration, there is always a possibility that soil conditions encountered during
construction are different than those described in this report. Therefore, it is recommended that a
qualified engineer observes and documents the construction, or Envirotech is promptly notified if
project and subsurface conditions found on-site are not as presented in this report so that we can
re-evaluate our recommendations.
This report presents geotechnical design guidelines, and is intended only for the owner, or
owners' representative, and location of project described herein. This report should not be used to
dictate construction procedures or relieve the contractor of his responsibility.
Any and all content of this geotechnical report is only valid in conjunction with the compliance of
all recommendations provided in this report. Semantics throughout this report such as `shall,'
`should' and `recommended' imply that the correlating design and/or specifications must be
adhered to in order to protect life and property. Semantics such as `suggested' or `optional' refer
that the associated design or specification may or may not be performed. The recommendations
provided in this report are valid for the proposed development at the issuance date of this report.
Changes to the site other than the expected development, changes to ordinances or regulatory
codes, or broadening of accepted geotechnical standards may affect the conclusions and
recommendations of this report.
The services described in this report were prepared under the responsible charge of Michael
Staten, a professional engineer with Envirotech. Michael Staten has appropriate education and
experience in the field of geotechnical engineering in order to assess landslide hazards,
earthquake hazards, and general soil mechanics.
Please contact Michael Staten at 360-275-9374 if you have any questions, comments, or require
additional information.
Sincerely,
Envirotec Engineering
Michael Staten, P.E.
Geotechnical Engineer
Envirotech Engineering Johnson Geotechnical Report
74 NE Hurd Road page 17 161 E Cardinal Court,Belfair
Belfair,Washington 98528 Parcel 12208 51 11010
Ph. 360-275-9374 Mason County,Washington
Fax: 360-275-4789 February 1, 2010
APPENDIX A
SITE PLAN
4
PROPOSED SEPTIC SCALE- I INCH = 40 FEET
DRAINFIELD L❑CATION 125FT± 0 5 10 o as
A RX, LOCATION OF
P POSED HOUSE
290 X EROSION
PROPERTY LINE----. TPl X CONTROL
e
X X
280 X X X X X
APPRX L❑CATION
OF PROPOSED
DRIVEWAY
0
0
270
9).
�:x
APPRX, TOP OF SL E
260 EXCEEDING 40%
CARDINAL
COURT
250
EXISTING
DRIVEWAY
(GRAVEL)
PROJECT/ OWNER/ LOCATION-
SINGLE FAMILY RESIDENCE
NOTES, GE❑TECHNICAL REPORT
1, EROSION CONTROL MAY BE REQUIRED FOR THIS SITE. GENERAL LOCATIONS
ARE DEPICTED, AND ALTERNATIVES MAY BE UTILIZED AS EXPLAINED IN THE STEPHEN 2085110OHNSON INC
GEOTECHNICAL REPORT, PARCEL COUNTY,
2. CONTOURS WERE NOT PREPARED BY A LICENSED LAND SURVEYOR. LEGEND MASON COUNTY, WASHINGTON
CONTOURS WERE EXTRAPOLATED FROM A PUBLIC LIDAR SOURCE (PREVIOUS
GEOTECHNICAL INVESTIGATION), AND INCORPORATED FIELD MEASUREMENTS AS TEMPORARY ENGINEER,
EXPLAINED IN THE GEOTECHNICAL REPORT. ++ +EROSION CONTROL ENVIROTECH ENGINEERING
3. BOUNDARIES WERE NOT PREPARED BY A LICENSED SURVEYOR. LOCATION OF 74 NE HURD ROAD
PROPERTY LINES AND SITE FEATURES, SUCH AS TOP OF SLOPES, WATER --� SLOPE INDICATOR BELFAIR, WASHINGTON 98528
FEATURES, ETC.., WITH RELATION TO THE PROPERTY LINES MUST BE 360-275-9374
VERIFIED BY THE OWNER. RECOMMENDATIONS IN THIS REPORT PROVIDE Bo EXISTING CONTOUR
SETBACKS, DEPTHS, ETC.. WITH RELATION TO GEOLOGIC FEATURES, NOT TPle TEST PIT SITE PLAN
PROPERTY LINES.
APPENDIX B
GEOLOGIC MAP
4
PROPOSED SEPTIC SCALE- I INCH = 40 FEET
DRAINFIELD L❑CATION
125FT± o s 1 F aD
q AP RX, L❑CATION OF
PROPOSED HOUSE
290
PROPERTY LINE--�,.
eTPI /
APPRX, 25FT BUILDING
SETBACK FROM TOP
OF 40% SLOPE
280 / i
10FT VEGETATI❑N
BUFFER, EXCEPT FOR
DRIVEWAY — No
c J
,270
APPRX LOCATION
OF PROPOSED
DRIVEWAY
APPRX, TOP OF SL E
260 EXCEEDING 40%
CARDINAL
COURT P RX. T E OF SL E
EXCEEDING 40%
250 REC❑MMENDE AREA
FOR DRAINAG
INFILTRATION
EXISTING
DRIVEWAY
(GRAVEL)
SOILS: MEDIUM DENSE TO DENSE SILTY
SAND WITH GRAVEL (SM) ❑VERLYING
DENSE SAND AND GRAVEL
PROJECT/ OWNER/ LOCATION-
SINGLE FAMILY RESIDENCE
NOTES GEOTECHNICAL REPORT
1. ALTERNATIVES FOR REDUCING BUILDING SETBACKS OR VEGETATION STEPHEN JOHNSON INC
BUFFERS MAY BE PROVIDED IN THE GEOTECHNICAL REPORT. PARCEL 12208511010
2. CONTOURS WERE NOT PREPARED BY A LICENSED LAND SURVEYOR, MASON COUNTY, WASHINGTON
CONTOURS WERE EXTRAPOLATED FROM A PUBLIC LIDAR SOURCE (PREVIOUS
GEOTECHNICAL STUDY), AND INCORPORATED FIELD MEASUREMENTS AS LEGEND
EXPLAINED IN THE GEOTECHNICAL REPORT. ENGINEER
3. BOUNDARIES WERE NOT PREPARED BY A LICENSED SURVEYOR. LOCATION ENVIROTECH ENGINEERING
OF PROPERTY LINES AND SITE FEATURES, SUCH AS TOP OF SLOPES, WATER SLOPE INDICATOR 74 NE HURD ROAD
FEATURES, ETC.., WITH RELATION TO THE PROPERTY LINES MUST BE BELFAIR, WASHINGTON 98528
VERIFIED BY THE OWNER, RECOMMENDATIONS IN THIS REPORT PROVIDE -BO EXISTING CONTOUR 360-275-9374
PROPERTY DEPTHS, ETC.. WITH RELATION TO GEOLOGIC FEATURES, NOT TPI@ TEST PI7 GE❑L❑GIC MAP
APPENDIX C
SOIL INFORMATION
VERTICAL AND HORIZONTAL SCALE,
I INCH = 40 FEET
ww-
0 10 20 40
PROPOSED HOUSE
EXISTING GRADE
MEDIUM DENSE TO
DENSE SILTY SAND
(SM)
DENSE SILTY SAND AND
SNDY GRAVEL
SECTION A-A
PROJECT/ OWNER/ LOCATION-
SINGLE FAMILY RESIDENCE
GE❑TECHNICAL REPORT
STEPHEN JOHNSON, INC
PARCEL 12208511010
MASON COUNTY, WASHINGTON
NOTES- ENGINEER
1) MINOR GRADE CHANGES REQUIRED IN ORDER TO ACHIEVE ENV IROTECH ENGINEERING
POSITIVE DRAINAGE 74 NE HURD ROAD
2) THE SOIL PROFILE IS ACCURATE FOR THE DEPTH OF HELFAIR, WASHINGTON 98528
THE OBSERVED TEST PITS AT THE SPECIFIED LOCATIONS. 360-275-9374
LOWER DEPTHS ARE BASED ON SITE GEOLOGY,
WELL LOG(S), AND/OR EXPERIENCE IN THE GENERAL AREA, SOIL PROFILE
TEST PIT LOG
TEST PIT NUMBER TP-1
PROJECT: SFR Geotechnical Report DATE OF LOG: 1/26/2010
PROJECT NO: 1005 LOGGED BY: MCS
CLIENT: Stephen Johnson, Inc EXCAVATOR: N/A
LOCATION: Parcel 12208511010 DRILL RIG: None
Mason County, Washington ELEVATION: N/A
INITIAL DEPTH OF WATER: N/A FINAL DEPTH OF WATER: N/A
STANDARD PENETRATION TEST
SOIL STRATA,
DEPTH SAMPLERS USCS DESCRIPTION LL PI CURVE
AND TEST DATA DEPTH N 10 30 50
0 ....... .... ............... . ..... . ..... . ..... . .. . . .
FTTT
SM Brown, moist, medium dense SILTY
SAND with GRAVEL. Gravel is primarily
well-graded and subangular. Sand is
1 mostly coarse. Low plasticity.
2 Light brown and grey, dense
3
4 Excavation terminated at approximately
4.0 feet
5
6
7
8
9
10
No Groundwater Encountered ENVIROTECH ENGINEERING
This information pertains only to this boring and should not be Geotechnical Engineering
interpreted as being indicitive of the entire site.
CD
w
AAB324 - Well I.D. NO
L
21659
0 A 9T E R W E L L R E P 0 R T Start Card No.
C. STATE OF WASHIMGTON Water Right Pernit No.
(1) OWNER; Name-REID-REALTY-INC
___BULLDOG____ Address
DRAWER, TT, WYCOFFJ STATION
--^ BREIVION,_WA--98310==-==____--
(<) LOCATION OF WELL: County MASON - -_- -NE114 SW 1/4 Sec 6 T 22 N., R 1W W
(2a) STREET ADDRESS OF WELL (or nearest address) KELLY LANE __________ ___ ___ ____________
-----------------------------------------------------------------------
(3) PROPOSED USE:-GROUP DOMESTIC--------------+__----_--'__ -- (10) WELL LOG __—
C (4) TYPE OF WORK: Owner's Number of well 1 Formation: Describe by color, character, size of material
0 (If more than one) 1 and structure, and show thickness of aquifers and the kind
NEW WELL Method: ROTARY 1 and nature of the material in each stratum penetrated, with
_ ___ __ _ __ _________ ______________ ___________; at least one entry for each change in formation.
0 (S) DIMENSIONS: _--_------- Diameter of well $ -_- inches -- --- --'—�_—'_"----—1 FROM 70 —
Drilled_199 it.
- Depth_of-completed well-199 ft. 1 MATERI
AL- - ---- - ------------- -===1 PIPE STICK-UP 1 2 � 4
L (6) CONSTRUCTION DETAILS: TOP SOIL
�O Casi installed, 8 " Dia. from 0 ft. to 178.8 ft. ) GRAYISH BROW SAPID & GRAVEL CLAY b q
- ' Dia. from ft. to ft. 1 BROW SAND GRAVEL 9 1 13
" Dia._from. ft. to ft. 1 BROW SAND GRAVEL & CLAY
__ --- ---------------------- ---- 1 GRAYISH BROWN SAPID & GRAVEL CLAY 13 : 54
Perforations: NO BROWN SAND SOME GRAVEL 1 54 1 140
Type of perforator used ( BROWN SAMD WATER 140 1 175)
L SITE of perforations in. by in. BROWN SAND SOME GRAVEL WATER ) 175 ) 199
perforations froa: ft. to ft. '
10 perforations from ft. to ft. '_ ,
perforations from ft. to ft. '
{R, Screens: YES ;
,
es Manufacturer's Name `
p Type STAINLESS Model No. TELESCOPING `
Diam. 8 slot size .020 from 178.5 ft. to 189.2 ft. ;
s Dian. 8 slot size .030 free 189.2 ft. to 194.4 ft. )
Gravel acked: NO Size of gqrave ;
C Gravel placed from ft. to
Surface seal: YES To what depth? 18 ft. 1 '
L Material used in seal BENTONITE '
rtT ,
Did any Strata contain unusable water? NO +
Type o� water? Depth of strata
F— Method of sealing strata off
z (7) PLW: Manufacturer's Name '
Type H.F.
0 (8) WATER LEVELS: Land-surface elevation '
above mean sea level ft. '
Static level 125 ft. below top of well Date 06/19/93 1
Artesian Pressure lbs. per square inch Date 1
0 Artesian water controlled by 1 Work started 06/14/93 Completed 06/18/93
0 ________________________________________________________________'______________________________=___________________________=_____
V (9) WELL TESTS: Drawdown is amount water level is lowered below 1 WELL CONSTRUCTOR CERTIFICATION:
L1J static level. I constructed and/or accept responsibility for cart-
Was Was a purrp test made? YES If yes by whoa? NICHOLSON DRILL 1 struction of this well, and its compliance with all
*, Yield: gal./min with f�. drawdown after hrs. l Washingtonand nformation5truction r ported ahaveaare,truettoimys used
best
C knowledge and belief.
Recovery data '
i Time Water Level Time Water Level Time Water Level 1 NAME NICHOLSON DRILLING INC
(Person, firm, or corporation) (Type or print)
1 ADDRESS PO X 123
p Date of test '
a Bailer test 10 ggal/min. 1 ft. drawdown after 1 hrs. 1 [SIGNED] License No. 0519
Air test gal min. w/ stem set at ft. for hrs.!
�-- Artesian flow g.p.m. Date 1 Contrac is
Temperature of water Was a chemical analysis made? NO 1 Registration No. N HODI1370M Date 07/02/93
APPENDIX D
SLOPE STABILITY
STABLE Slope Stability Analysis System
New User
Project SJohnson CardlnalST
Datafile: dynamic Bishop
STABLE Version 9.03.00u
Bishop
##w*+#www+++###**+w+++****++*##*ww+#twwww++#+*wwa###***+w#
TITLE
dynamic
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UNITS (Metric/Imperial) I
+++a*aa++a++aaaaa+++waaa+++wwa+++tw+a++a+aa+aa++wwawaaa++a
GEOMETRY DEFINITION
POINTS
NO. X Y
1 0.000 0.000
2 50.000 -12.000
3 71.000 -22.000
4 101.000 -32.000
5 157.000 -32.000
6 15.700 -3.770
7 22.310 -5.350
8 28.920 -6.940
9 35.530 -8.530
10 42.140 -10.110
11 48.750 -11.700
12 55.360 -14.550
13 61.970 -17.700
14 68.580 -20.850
15 75.190 -23.400
16 81.810 -25.600
17 88.420 -27.810
18 95.030 -30.010
19 101.640 -32.000
20 108.250 -32.000
21 114.860 -32.000
22 121.470 -32.000
23 128.080 -32.000
24 134.690 -32.000
25 141.300 -32.000
LINES
Lo X Hi X SOIL
1 2 1
2 3 1
3 4 1
4 5 1
SOILS
SOIL NAME LINETYPE-PEN COHESION FRICTION UNIT WT.
1 Soil-1 CONTINUOUS-BLACK 100.00 36.0 135.000
++#++a****w+++##ww+++++w++++#w+#+++a#+w+**+++++#+*w+++++++
PORE PRESSURE SPECIFICATION
STABLE02002 MZ Associates Ltd Printed on: 30101/10 @ 15:46:07 Page: 1
STABLE Slope Stability Analysis System
New User
Project : SJohnson CardinalST
Datafile: dynamic Bishop
SOIL PIEZO RU EXCESS
Y/N/P Value Value
1 N 0.000 0.000
PlEZOf—%TR1C SURFACE
POINT
POINT PORE PRESSURES
POINT PRESSURE
SLIP DIRECTION (+/- X) _ +
SLIP-CIRCLES
AUTOMATIC
Circle Centre Grid Extremities
125.600
15.700 * * 141.300
* +
0.000
X spacing -- no. of cols (max 10)= 10
Y spacing -- no. of rows (max 20)- 20
Grid 1 Circles through point 6
Grid 2 Circles through point 7
Grid 3 Circles through point 8
Grid 4 Circles through point 9
Grid 5 Circles through point 10
Grid 6 Circles through point 11
Grid 7 Circles through point 12
Grid 8 Circles through point 13
Grid 9 Circles through point 14
Grid 10 Circles through point 15
Grid 11 Circles through point 16
Grid 12 Circles through point 17
Grid 13 Circles through point 18
Grid 14 Circles through point 19
Grid 15 Circles through point 20
Grid 16 Circles through point 21
Grid 17 Circles through point 22
Grid 18 Circles through point 23
Grid 19 Circles through point 24
Grid 20 Circles through point 25
STABLE02002 MZ Associates Ltd Printed on: 3=1110 15:46:07 Page: 2
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APPENDIX E
EROSION CONTROL
GEOTEXTILE FABRIC 2'x2' WOOD POST (TYP) GEOTEXTILE FABRIC
WRAP AROUND TRENCH DR EQUIVALENT OR BETTER AND WIRE MESH
TO AT LEAST ENTIRE 2 6 FT MAX. O.C.
BOTTOM OF TRENCH OS FT
BEFORE PLACING GRAVEL 2'x2'x5' WOOD POST OR �- 6 FT
12' DEEP, 8' WIDE TRENCH f EQUIVALENT OR BETTER EXISTING
FILLED WITH 3/4' TO 1 1/2' GROUND SURFACE 2 T
WASHED GRAVEL
2.5 FT 12' DEEP, 8' WIDE
DIRECTION OF + l T
WATER FLOW 1 EXISTING TRENCH FILLED WITH
GROUND SURFACE 3/4' TO 1 1/2' 2.5 FT
12 2.5 FT WASHED GRAVEL `
J
8. BOTTOM EXTENTS OF
GEOTEXTILE FABRIC SILT FEN. - DETAIL
SILT FENCE - CR_cS SECTION N.T.S.
N.T.S. HAY OR STRAW MATTING
ENERAL NOTES- 1. STRAW SHALL BE AIR DRIED, AND FREE FROM WEED SEEDS AND
COARSE MATERIAL.
SHOULD THE TEMPORARY EROSION AND SEDIMENT CONTROL MEASURES SHOWN ON 2. APPLY AT APPROXIMATELY 75 TO 100 POUNDS PER 1000 SQUARE
HESE PLANS PROVE TO BE INADEQUATE DURING CONSTRUCTION, THE CONTRACTOR FEET OF GROUND.
HALL INSTALL ADDITIONAL EROSION AND SEDIMENT CONTROL FACILITIES. 3. MINIMUM THICKNESS SHALL BE 2 INCHES.
ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE 4. HAY OR STRAW IS SUBJECT TO BLOWING. KEEP MOIST OR TIED
NSPECTED DAILY AND IMMEDIATELY MAINTAINED, IF NECESSARY. DOWN,
3. ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE LEFT IN
LACE UNTIL THE UPSLOPE AREAS HAVE BEEN PERMANENTLY STABILIZED. PERMANENT EROSION CONTROL NOTES:
EMPORARY EROSION CONTROL NOTES- SEEDING FOR RAW SLOPES
OR ALL AREAS WHICH HAVE BEEN STRIPPED OF VEGETATION OR EXPERIENCED LAND 1. BEFORE SEEDING, INSTALL NEEDED SURFACE RUNOFF CONTROL
ISTURBING ACTIVITIES, AND WHERE NO FURTHER WORK IS ANTICIPATED FOR A MEASURES SUCH AS GRADIENT TERRACES, INTERCEPTOR DIKES,
ERIOD EXCEEDING THE LISTED CRITERIA BELOW, ALL DISTURBED AREAS MUST BE SWALES, LEVEL SPREADERS AND SEDIMENT BASINS.
MMEDIATELY STABILIZED WITH MULCHING, GRASS PLANTING OR OTHER APPROVED 2. THE SEED BED SHALL BE FIRM WITH FAIRLY FINE SURFACE,
ROSION CONTROL TREATMENT APPLICABLE TO THE TIME OF YEAR. GRASS SEEDING FOLLOWING SURFACE ROUGHENING. PERFORM ALL OPERATIONS ACCR❑S
LONE WILL ONLY BE ACCEPTABLE DURING THE MONTHS OF APRIL THROUGH OR PERPENDICULAR TO THE SLOPE.
EPTEMBER. HOWEVER, SEEDING MAY PROCEED WHENEVER IT IS IN THE INTEREST OF 3. SEEDING RECOMMENDATIONS, AS SHOWN BELOW, AND SHOULD BE
HE OWNER/CONTRACTOR, BUT MUST ALSO BE AUGMENTED WITH MULCHING, NETTING APPLIED AT THE RATE OF 120 POUNDS PER ACRE.
R OTHER APPROVED TREATMENT. 4. SEED BEDS PLANTED BETWEEN MAY 1 AND OCTOBER 31 WILL
REQUIRE IRRIGATION AND OTHER MAINTENANCE AS NECESSARY TO
RY SEASON (MAY 1 THRU SEPTEMBER 30) -- THE CLEARING OF LAND, INCLUDING THE FOSTER AND PROTECT THE ROOT STRUCTURE.
EMOVAL OF EXISTING VEGETATION OR OTHER GROUND COVER, MUST BE LIMITED TO 5, SEED BEDS PLANTED BETWEEN NOVEMBER 1 AND APRIL 30,
NLY AS MUCH LAND AS CAN RECEIVE APPROPRIATE PROTECTIVE COVER OR BE ARMORING OF THE SEED BED WILL BE NECESSARY, (e.g.,
THERWISE STABILIZED, AFTER HAVING BEEN CLEARED OR OTHERWISE DISTURBED , GE❑TEXTILES, JUTE MAT, CLEAR PLASTIC COVERING).
Y NO LATER THAN SEPTEMBER 30 OF A GIVEN YEAR. UNLESS IMMEDIATE 6. FERTILIZERS ARE TO BE USED ACCORDING TO SUPPLIERS'
TABILIZATION IS SPECIFIED IN THE EROSION AND SEDIMENT CONTROL PLAN, ALL RECOMMENDATIONS. AMOUNTS SHOULD BE MINIMIZED, ESPECIALLY
REAS CLEARED OR OTHERWISE DISTURBED MUST BE APPROPRIATELY STABILIZED ADJACENT TO WATER BODIES AND WETLANDS.
HR❑UGH THE USE OF MULCHING, NETTING, PLASTIC SHEETING, EROSION BLANKETS,
REE DRAINING MATERIAL, ETC., BY SEPTEMBER 30 OR SOONER PER THE APPROVED USE THE FOLLOWING RECOMMENDED SEED MIXTURE FOR EROSION
LAN OF ACTION. UNLESS OTHERWISE APPROVED BY THE COUNTY, SEEDING, CONTROL, OR A COUNTY APPROVED ALTERNATE SEED MIXTURE.
ERTILIZING AND MULCHING OF CLEARED OR OTHERWISE DISTURBED AREAS SHALL BE
ERFORMED DURING THE FOLLOWING PERIODS- MARCH 1 TO MAY 15, AND AUGUST 15 TO PROPORTIONS PURITY GERMINATIO
CTOBER 1. SEEDING AFTER OCTOBER 1 WILL BE DONE WHEN PHYSICAL COMPLETION NAME BY WEIGHT(%) (%) (%)
F THE PROJECT IS IMMINENT AND THE ENVIROMENTAL CONDITIONS ARE CONDUCIVE
❑ SATISFACTORY GROWTH. IN THE EVENT THAT PERANENT STABILIZATION IS NOT REDTOP (AGROSTIS ALBA) 10 92 90
OSSIBLE, AN ALTERNATIVE METHOD OF GROUND COVER, SUCH AS MULCHING, NETTING, ANNUAL RYE (LOLIUM MULTIFLORUM) 40 98 90
LASTIC SHEETING, EROSION BLANKETS, ETC., MUST BE INSTALLED BY NO LATER THAN CHEWING FESUE 40 97 80
EPTEMBER 30. (FESTUCA RUBRA COMMUTATA)
(JAMESTOWN, BANNER, SHADOW, KOKET)
N THE EVENT THAT CONSTRUCTION ACTIVITIES OR OTHER SITE DEVELOPMENT WHITE DUTCH CLOVER 10 96 90
CTIVITIES ARE DISCONTINUED FOR AT LEAST 4 CONSECUTIVE DAYS, THE (TRIFOLIUM REPENS)
WNER/CONTRACTOR SHALL BE RESPONSIBLE FOR THE INSPECTION OF ALL EROSION
ND SEDIMENT CONTROL FACILITIES IMMEDIATELY AFTER STORM EVENTS, AND AT MULCHING
EAST ONCE EVERY WEEK, THE OWNER/ CONTRACTOR SHALL BE RESPONSIBLE FOR
HE MAINTENANCE AND REPAIR OF ALL EROSION AN SEDIMENT CONTROL FACILITIES. 1. MATERIALS USED FOR MULCHING ARE RECOMMENDED TO BE WOOD
FIBER CELLULOSE, AND SHOULD BE APPLIED AT A RATE OF 1000
ET SEASON (OCTOBER 1 THRU APRIL 30) -- ON SITES WHERE UNINTERUPTED POUNDS PER ACRE.
ONSTRUCTION ACTIVITY IS IN PROGRESS, THE CLEARING OF LAND, INCLUDING THE 2. MULCH SHOULD BE APPLIED IN ALL AREAS WITH EXPOSED SLOPES
EMOVAL OF EXISTING VEGETATION AND OTHER GROUND COVER, SHALL BE LIMITED GREATER THAN 21 (HORIZ❑NTAL-VERTICAL).
❑ AS MUCH LAND AREA AS CAN BE COVERED OR STABILIZED WITHIN 24 HOURS IN 3. MULCHING SHOULD BE USED IMMEDIATELY AFTER SEEDING OR IN
HE EVENT A MAJOR STORM IS PREDICTED AND/ OR EROSION AND SEDIMENT AREAS WHICH CANNOT BE SEEDED BECAUSE OF THE SEASON. ALL
TRANSPORT OFF-SITE IS OBSERVED. AREAS REQUIRING MULCH SHALL BE COVERED BY NOVEMBER 1,
LL CLEARED OR DISTURBED AREAS SHALL RECEIVE APPROPRIATE PROTECTIVE
OVER OR BE OTHERWISE STABILIZED, SUCH AS MULCHING, NETTING, PLASTIC
HEETING, EROSION BLANKETS, FREE DRAINING MATERIAL, ETC., WITHIN 5 DAYS AFTER
AVING BEEN CLEARED OR ❑THERWISE DISTURBED IF NOT BEING ACTIVELY WORKED.
ILT FENCING, SEDIMENT TRAPS, SEDIMENT PONDS, ETC., WILL NOT BE VIEWED AS
DEQUATE COVER IN AND OF THEMSELVES. IN THE EVENT THAT ANY LAND AREA NOT
EING ACTIVELY WORKED REMAINS UNPROTECTED OR HAS NOT BEEN APPROPRIATELY
TABILIZED 5 DAYS AFTER HAVING BEEN CLEARED, ALL CONSTRUCTION ACTIVITY ON
HE SITE, EXCEPT FOR APPROVED EROSION AND SEDIMENT CONTROL ACTIVITY, SHALL
MMEDIATELY CEASE UNTIL SUCH A TIME AS AFOREMENTIONED LAND AREA HAS BEEN
PPROPRIATELY PROTECTED OR STABILIZED.
SILT FENCE
PROJECT/ OWNER/ LOCATION:
1. GEOTEXTILE FILTER FABRIC TYPE SHALL BE PER SPECIFIED IN THE 'STORMWATER MANAGEMENT MANUAL SINGLE FAMILY RESIDENCE
OR THE PUGET SOUND BASIN,' OR APPLICABLE COUNTY STANDARDS
2. GEOTEXTILE FILTER FABRIC SHALL BE PURCHASED IN A CONTINUOUS ROLL CUT TO THE LENGTH OF GEOTECHNICAL REPORT
EACH BARRIER TO AVOID USE OF JOINTS. IF JOINTS ARE NECESSARY, FILTER FABRIC SHALL BE SPLICED STEPHEN JOHNS❑N INC.,
TOGETHER ONLY AT A SUPPORT POST WITH A MINIMUM 6-INCH OVERLAP AND SECURELY FASTENED AT PARCEL 12206511010
BOTH ENDS TO THE POST. MASON COUNTY, WASHINGTON
STANDARD FILTER FABRIC SHALL BE FASTENED USING V STAPLES OR TIE WIRES (HOG RINGS) 2 4 IN
PACING.
POSTS SHALL BE SPACED AND PLACED AT DEPTHS INDICATED IN THE DETAILS ON THIS SHEET, AND ENGINEER,
RIVEN SECURELY INTO THE GROUND. ENVIROTECH ENGINEERING
. WIRE MESH SHALL BE 2'X2'X14 GAUGE OR EQUIVILENT. THE WIRE MESH MAY BE ELIMINATED IF 74 NE HURD ROAD
XTRA-STRENGTH FILTER FABRIC (MONOFILAMENT), AND CLOSER POST SPACING IS USED. BELFAIR, WASHINGTON 98528
. A TRENCH SHALL BE EXCAVATED ACCORDING TO THE DETAILS ON THIS SHEET ALONG THE LINE OF THE 360-275-9374
❑STS AND UPSLOPE FROM THE SILT FENCE.
SILT FENCES SHALL BE LOCATED DOWNSLOPE FROM THE CLEARING LIMITS OF THE PROJECT. EROSION CONTROL
APPENDIX F
DRAINAGE DETAILS
FINAL GROUND
SURFACE GE❑TEXTILE FABRIC WRAPPED
AROUND QUARRY SPALL
CORRUGATED TIGHTLINE 8-12 INCH QUARRY SPALL OR
6-INCH MIN. DIAMETER APPROVED INFILTRATION MEDIA
1
., .O .00O.O.00OOOOO.
O 000000000000 1 FT MIN
O0O0O0O�O�O0O
SUBSURFACE DRAINAGE DETAILS
N.T.S,
NOTE:
INFILTRATION FACILITY COMPONENTS
AND SIZE MAY NEED TO BE DETERMINED
BY A DRAINAGE ENGINEER AND/ OR
PREVAILING GOVERNMENT AGENCY,
PROJECT/ OWNER/ LOCATION-
SINGLE FAMILY RESIDENT
GE❑TECHNICAL REPORT
STEPHEN JOHNSON INC
PARCEL 12208511010
MASON COUNTY, WASHINGTON
ENGINEER,
ENVIROTECH ENGINEERING
74 NE HURD ROAD
BELFAIR, WASHINGTON 98528
360-275-9374
DRAINAGE DETAILS