HomeMy WebLinkAboutGeoTech Report - BLD Engineering / Geo-tech Reports - 7/1/2008 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. 1 �n/1rr
Applicant/Owner ►f I K941 yip dy Parcel# / ?3 2t�l 22 OOC 550
Site Address <—U Eim (&/C
(1) (a)A discussion of genera
,Lgeologic conditions in the vicinity of the proposed development,
Located on page(s)
(b) A discussion of specific soil types
Located on page(s) 5
(c) A discussion of ground water conditions
Located on page(s) 6
(d) A discussion of the u slope geomorphology
Located on page(s)
(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) /01
(2) A site plan which identifies the important development and geologic features.
Located on Map(s)�:-�e plan Lhoo• )
it-
(3) Locations and logs of exploratory hole or pro
Located on Map(s) 5,4 Plati
(4) The area of the proposed development,the boundaries of the hazard, and associated buffers and
setbacks shall be delineated (top, both sid s, and toe)on a geologic map of the site.
Located on Map(s) o 0
r
(5) A minimum of one cross section at a scale which adequately depicts the subsurface profile, and
which incorporates the details o�gradechanges.
Located on Maps)� G
117
(6) A description and results of slope stability analyses performed for both static and seismic loading
conditiot.Analysis should examine worst case failures.The analysis should include the
Slmplifa'Q�Bishop's Method of Circles. The minimum static safety factor is 1.5, the minimum
seismic safety factor i 1.1. 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) If
(b) Appropriate restrictions on placement of septic drain fields
Locate 'n�p age(s) I
(c) Ap opriate restrictions on placement of compacted fills and footings
Located on page(s) �� 9
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 property.l�
Located on page(s)
(e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of
other slopes on the property.
Located on page(s) I2
(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)
(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, landsli es and har ful construction methods.
Located on page(s) 7, 1900� F
(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). 1 2T134 it
(12) Recommendations for the preparation of structural mitigation or details of other proposed
mitigation. Ad
Located on page(s)—& 1
(13) A site map drawn to scale showing the property boundaries, scale, north arrow, and the location
and nature of existing and proposed2aa'4)
elopment on the site.
Located on Ma s ;
I, 'GYff_
MWS, hereby certify under penalty of
perjury that I am a civir 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 conditions. I also certify that the Geotechnical
Report, dated TcAly I , 2009 i
, and entitled ,cdL�-4--
Tr'r I\C✓I Y Je;, &A,11C Kp 4,J&cPi meets all the requirements of the Mason
County Resource Ordinatrice, Lands de Hazard Section, is complete and true, that the assessment
demonstrates conclusively that the risks posed by the landslide hazard can be mitigated throu h the
Included geotechnical design recommendations, and that all hazards are mitigated i as
to prevent harm to property and public health and safety. (Signature and Stamp)
IDN
DCPIHES Tif /D 20i0o1
Page 2 of 2 Form Effective June 2008
Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report.
RECEIVED
`AUG 2 8 2008
SELFAIR OFFICE
Geotechnical Report
for
Kennedy Single Family Residence
NE Fern Way
Parcel 12329 22 00080
Mason County, Washington
July 1, 2008
Project#0864
prepared For:
Bill and Michelle Kennedy CLYDEST
PO Box 77 1L0 0�WAS& q�F
Belfair, Washington 98528
0
Prepared By:
Envirotech Engineering A�o� '�Fc s5�°
74 NE Hurd Road �SS��NAIL,
Belfair, Washington 98528
Phone: 360-275-9374 EXPIRES JAN 10,2009
Fax: 360-275-4789
TABLE OF CONTENTS
1.0 INTRODUCTION........................................................................................................................... 1
1.1 PROJECT INFORMATION............................................................................................................... 1
1.2 PURPOSE OF INVESTIGATION........................................................................................................ 1
1.3 SCOPE OF WORK........................................................................................................................... 1
2.0 SURFACE CONDITIONS..............................................................................................................3
2.1 GENERAL OBSERVATIONS ............................................................................................................ 3
2.2 TOPOGRAPHY............................................................................................................................... 3
2.2.1 Upslope Geomorphology....................................................................................................... 3
2.2.2 Downslope Geomorphology.................................................................................................. 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 TESrING........................................................................ 5
3.2 GENERAL GEOLOGIC CONDITIONS............................................................................................... 5
3.3 SPECIFIC SUBSURFACE CONDITIONS............................................................................................. 5
3.3.1 Groundwater......................................................................................................................... 6
3.4 SOILS TESTING.............................................................................................................................6
3.4.1 Visual Classification............................................................................................................. 6
4.0 ENGINEERING ANALYSIS,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.................................................................... 8
4.3.1 Excavation............................................................................................................................ 8
4.3.2 Placement and Compaction of Native Soils and Engineered Fill.......................................... 9
4.3.3 Retaining Wall Backfill......................................................................................................... 9
4.3.4 Wet Weather Considerations............................................................................................... 10
4.4 SLOPE STABILITY AND EROSION CONTROL................................................................................ 10
4.4.1 Septic Drainfield Impacts...............................................................................I.................... 12
4.4.2 Building and Footing Setbacks........................................................................................... 12
4.4.3 Temporary and Permanent Erosion Control....................................................................... 13
4.4.4 Surface and Subsurface Drainage...................................................................................... 14
4.4.5 Vegetation Considerations.................................................................................................. 14
4.4.6 On-site and Off-site impacts................................................................................................ 14
4.5 SEISMIC CONSIDERATIONS AND LIQUEFACTION......................................................................... 15
5.0 CLOSURE..................................................................................................................................... 16
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
1.0 INTRODUCTION
Envirotech Engineering (Envirotech) has completed a geotechnical investigation for a property
located on NE Fern Way, identified as parcel number 12329 22 00080, Mason County,
Washington (Project). 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, recommendations for foundation, settlement, earthwork construction, lateral earth
pressures, slope stability, erosion control, drainage and vegetation considerations in the
Engineering Analysis and Recommendations Section.
An initial geotechnical evaluation of the Project was conducted by Envirotech with the property
owner, Bill Kennedy, on June 17, 2008. 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 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.
1.1 Project Information
Information pertaining to the Project was provided by the property owner and owner's
representative with general assumptions by Envirotech that are typical of this type of
development. The Project is accessed from NE Fem Way, a gravel surfaced road, linking NE
Sand Hill Road. See the vicinity map on the following page of this report. The property is
currently occupied land with a mobile home and other ancillary features. The mobile home is
expected to be removed. The planned development consists of a 2- or 3-story single family
residence which may include a daylight basement. Foundation construction is expected to consist
of continuous strip footings and concrete slab-on-grade or stem walls. An on-site septic system
and driveway exists on the property. Approximate building footprint with relation to site features
are illustrated in the Site Map in Appendix A.
1.2 Purpose of Investigation
The purpose of this geotechnical investigation was to evaluate the Project in order to provide
geotechnical recommendations relating to the development of the property. The investigation
included characterizing the general Project surface and subsurface conditions, and evaluating the
suitability of the soils to support the planned site activities.
1.3 Scope of Work
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;
• Conduct a site visit to document the site conditions that may influence the construction
and performance of the proposed improvements;
• Define the general subsurface conditions of the site by observing subsoils extending to a
Envirotech Engineering Geotechnical Investigation
Ph. 360-275-9374 page 1 Parcel 12305 1100040
Fax: 360-275-4789 Mason County,Washington
July 1, 2008
depth of up to 3 feet below the natural ground surface, 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 properties of the soils that include 3
visual classifications;
• 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.
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Vicinity Map from Mason County Website
Envirotech Engineering Geotechnical Investigation
Ph. 360-275-9374 page 2 Parcel 12305 1100040
Fax:360-275-4789 Mason County,Washington
July 1,2008
2.0 SURFACE CONDITIONS
Information pertaining to the existing surface conditions for the Project was gathered on June 17,
2008 by Michael Staten, geotechnical engineer with Envirotech. During the site visit, the type of
geotechnical investigation was assessed, site features were documented that may influence
construction and slope stability, soil samples were collected from selected locations, and near-
surface soils were visually classified. 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 Project is currently developed land as previously mentioned. Fern Way borders the north
property line. Beyond the property lines, rural residential development exists. Vegetation on and
near the Project consists primarily of firs, 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 Project is situated within and near moderate to steep sloping terrain. The planned building
envelope location is primarily on slightly sloping terrain of less than 7%. The topographic
information provided in this section was extrapolated from a public lidar source, and incorporated
observations and field measurements. Slope verification included measuring slope lengths and
inclinations with a cloth tape and clinometer. 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.
2.2.1 Upslope Geomorphology
Ascending grades are located to the west of the planned development. This slope is minor
with apparent grades of less than 10%, and extends more than 300 feet with minor
undulation. There are no apparent water bodies or wetlands located upslope from the
planned development.
2.2.2 Downslope Geomorphology
Descending slopes with varying grades of no more than 49% exist to the east of the
planned development. The combined vertical relief is less than 100 feet at the location of
the steepest slopes.
2.3 Surface Drainage
Stormwater runoff originating upslope from the anticipated development is expected to be
minimal. Sheet flow down the slightly sloping grades towards the east is expected. Most of the
runoff is diverted towards the east property line. Excessive scour, erosion or other indications of
past drainage problems were not observed at or near the planned development.
Envirotech Engineering Geotechnical Investigation
Ph. 360-275-9374 page 3 Parcel 12305 1100040
Fax: 360-275-4789 Mason County,Washington
July 1, 2008
2.4 Slope and Erosion Observations
The existing steep slopes 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 or naturally 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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Aerial Photo from Mason County website
Envirotech Engineering Geotechnical Investigation
Ph. 360-275-9374 page 4 Parcel 12305 1100040
Fax: 360-275-4789 Mason County,Washington
July 1,2008
3.0 SUBSURFACE INVESTIGATION
Information on subsurface conditions pertaining to the Project was gathered on June 17, 2008 by
Michael Staten, geotechnical engineer with Envirotech. Specific information on field methods,
sampling, field testing, 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-sections, test pit log(s) representative of the
bearing soils of the planned building, and water well report(s). Applicable test pit and well log
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 3 feet below the existing ground surface. Information on
subsurface conditions also included reviewing geological maps and water well reports originating
from nearby properties.
One bulk sample was collected at the Project site at approximately 1 foot 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
moderate dense soils in the upper 18 inches, and dense soils from 18 inches to the depth of
terminous.
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.
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 described utilizing the Unified Soil Classification System
(USCS). Using the USCS in conjunction with estimated relative densities and other anticipated
engineering properties of the soil, susceptibility for potential landslides, erosion and seismic
hazards may be assessed.
The Project is composed of native soils with no indications of borrowed fill. For engineering
Envirotech Engineering Geotechnical Investigation
Ph. 360-275-9374 page 5 Parcel 12305 1100040
Fax: 360-275-4789 Mason County,Washington
July 1, 2008
,
purposes,these native soils consist of distinguishable layers, as presented below.
Soils within the upper 18 inches of natural ground were observed to be brown, silty sand with
gravel (SM). The relative densities of this soil are provided in Section 3.1 of this report. Gravel
was primarily fine and subrounded. Sand was mostly well-graded, and the fines content exhibited
low plasticity.
Soils below the upper 18-inch soil layer to a depth of at least 3 feet were observed to consist of
brown and grey, well-graded sand with gravel (SW). According to the well reports and
knowledge of the general area, soils below the observed 3 feet in depth to about 50 feet below the
existing ground surface are dense sandy soils.
3.3.1 Groundwater
From the water well report and knowledge of the general area, permanent groundwater is
approximately 100 feet directly below the property at the building pad location. Perched
groundwater at shallow depths was not observed on-site, but indicated on a well report at
a depth of 60 feet.
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. The following soil tests were performed in accordance with the American Standards for
Testing and Materials (ASTM):
3 Visual Classifications(ASTM D2488)
3.4.1 Visual Classification
The results from the visual classification are presented above in the Subsurface
Conditions Section at depths of up to 3 feet below the natural ground surface.
Specifically, soils below the upper 18 inches consisted of approximately 70% sand-sized
soils, 25% gravel, and less than 5% silt. 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 Geotechnical Investigation
Ph 360-275-9374 page 6 Parcel 12305 1100040
Fax: 360-275-4789 Mason County,Washington
July 1,2008
4.0 ENGINEERING ANALYSIS,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
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 two- or
three-story, single family residential structure. Below the upper 12 inches of Project soils, there
are apparently two distinguishable layers of soil that will influence the bearing capacity and
settlement of the structures. 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, and deriving probable relative densities, unit weights
and angles of internal friction of the in-situ soils based on observed field conditions and soil
testing for this Project.
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
For the existing site conditions, bearing values should increase with depth. 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. Footing width and depth
recommendations shall be adhered to,and are based on 1500 pounds per square feet(psf)
maximum structural bearing pressure.
For a bearing capacity requirement of no more than 1500 psf, a minimum footing width
of 16 inches shall be placed at a minimum of 18 inches below the existing ground
surface. Foundation recommendations are made available based on adherence to the
remaining recommendations that are provided in this report.
4.1.2 Settlement
Total and differential settlement that a structure will undergo depends primarily on the
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
Envirotech Engineering Geotechnical Investigation
Ph 360-275-9374 page 7 Parcel 12305 1100040
Fax: 360-275-4789 Mason County,Washington
July 1,2008
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 6 inches of compacted
coarse, granular material that is placed over undisturbed native subgrade or engineered
fill. Native soils found at the Project may be suitable for use as the material directly
beneath concrete slabs if the material consists of less than 5% fines. Although not
required for the structural integrity of the concrete slab-on-grade, a vapor barrier is
usually used for damp-proofing. If vapor barriers are used, it is suggested to utilize a
barrier that is sufficiently thick to resist puncturing during construction, or place a 2 inch
layer of sand above the barrier prior to placing the concrete slab.
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 70 pcf for backfill consisting of engineered fill and native soils,
respectively. 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 retaining structures having relatively flat or
descending sloping backfill, and the backfill conforming to the recommendations outlined in the
Earthwork Construction Recommendations Section of this report. For instances when it is
necessary to have ascending sloping backfill or structures will induce passive earth pressures,
additional design parameters must be accounted for in the retaining wall analysis. For these cases,
recommendations should only be provided by a qualified engineer after the type of backfill is
specified, inclination of backfill slope is estimated, and the final wall height is determined.
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,t,,W 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
Envirotech Engineering Geotechnical Investigation
Ph. 360-275-9374 page 8 Parcel 12305 1100040
Fax: 360-275-4789 Mason County, Washington
July 1,2008
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 recommended prior to
foundation construction. The following placement and compaction requirements arc
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 I
i.
UNDISTURBED SUBGRADE
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 60%to 100%gravel-sized material (particles between 3/16-inch and
3 inches), and less than 10%fines (particles passing#200 standard sieve)by weight.
Compaction shall be achieved in compacted lifts not to exceed 8 inches and 12 inches for
1 uniformly compacted to
native soils and engineered fill, respectively. Each lift should be S p
° modified Proctor maximum density ASTM D 1557) and within
at least 95/° of the mod �' Y (
/° of opti
mum imum moisture content. Each lift surface should be adequately maintained
�
during construction in order to achieve acceptable compaction and inter-lift bonding.
4.3.3 Retaining Wall Backfill
Native soils may be used as retaining wall backfill for this Project. Backfill may also
consist of engineered fill, as presented in this report, or borrow material approved by a
Envirotech Engineering Geotechnical Investigation
Ph. 360-275-9374 page 9 Parcel 12305 1100040
Fax: 360-275-4789 Mason County,Washington
July 1, 2008
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). Over-compaction should
be prevented since this will cause lateral earth pressures to increase, which may be
detrimental to the retaining structure. If clean, coarse gravel soils are utilized as
engineered fill, compaction may be achieved from 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. At the ground surface, backfill should extend horizontally from
e
the face of the retaining wall to at least 2 feet in back of the wall. Perforated drains for
retaining walls should have a minimum diameter of 4 inches and direct water to an
appropriate outfall as recommended in the Surface and Subsurface Drainage Section of
1
this report. Coarse, clean gravel is recommended to be placed at least 12 inches around
the drain pipe in order to provide increased drainage capabilities. Non-woven geotextile
filter fabric 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,
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.
4.4 Slope Stability and Erosion Control
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. 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. With
appropriate drainage and erosion control provisions for this Project during and after construction,
it is unlikely that this Project will experience excessive surficial movements. However,
maintenance of the slope must be completed if the situation does arise in order to prevent the
possibility of further surficial or deep seated slope movements that may be damaging to life and
property.
Envirotech Engineering Gcotechnical Investigation
Ph. 360-275-9374 page 10 Parcel 12305 1100040
Fax: 360-275-4789 Mason County, Washington
July 1, 2008
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 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. See the
DNR map provided later in this report.
The Simplified Bishop Method, utilizing `STABLE' software, was used to analyze the static
stability of the site slopes. 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, 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:
Upper 15 feet
• Soil unit weight: 134 pcf
• Angle of internal friction: 35 degrees
• Cohesion: 0 psf
Soils below 15 feet
• Soil unit weight: 115 pcf
• Angle of internal friction: 40 degrees
• Cohesion: 0 psf
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.
Envirotech Engineering Geotechnical Investigation
Ph. 360-275-9374 page 11 Parcel 12305 1100040
Fax: 360-275-4789 Mason County,Washington
July 1, 2008
Anticipated building loads, building pad cuts, or impacts from septic drainfields are not expected
to have any detrimental influence on the global stability of the slopes, provided that the setback
requirements, drainage and all other recommendations in this report are adhered to. Based on the
aforementioned Project criteria, observations, slope stability analysis, and the recommendations
in this report, the Project has an acceptable factor of safety of over 1.5 relative to deep-seated,
static slope failures. Furthermore,an acceptable factor of safety of over 1.1 for seismic conditions
was also concluded for this Project. See the slope stability information in Appendix D for input
parameters and example of outputs. For this project, minimum factor of safeties for static and
dynamic conditions were estimated to be 1.9 and 1.3, respectively.
.21�F F��///ff///
� Fslc
_ 17 I,
TA_
f Fx F
1{
!'30 *7 2 1708024 1 r.
� Project
ti
F r f Fy—
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i"
FW
FW rW
Frf'rw Fy
- rW FlY FW f y. x F R F _.. I• I •ti
F1M1'f• I FW FW FW `A N A'I FF��If r FV �.V
FW F FW FW FW�.. FW .k AI.FI(W rW P--- '
0.R1 FW Fri
FW FWW F -1 AAr FW FW
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gAa iw..F. AA.Ni.{Ra a.Tkw rx
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rl�• _ Ak-:__-'FXW F'- _. .
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Map from Washington StateDepartment of Natural Resources Website
4.4.1 Septic Drainfield Impacts
The approximate location of the existing septic drainfield is presented on the Site Plan in
Appendix A of this report. Based on the location of the drainfield with relation to
existing/ proposed topography and the proposed building location, the drainfield is not
expected to adversely influence the planned development.
4.4.2 Building and Footing Setbacks
Conservative surcharges from the anticipated site development were used in the slope
stability analysis. 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 50 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.
Envirotech Engineering Geotechnical Investigation
Ph. 360-275-9374 page 12 Parcel 12305 1100040
Fax: 360-275-4789 Mason County, Washington
July 1, 2008
STRUCTURE
TOP OF
SLOPE SLOPE
FACE
-I I �
50 FT MIN -� FOOTING
4.4.3 Temporary and Permanent Erosion Control
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.
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. Straw is presented in this report as the first
choice for temporary erosion control, if necessary. 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, if necessary.
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.
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. Erosion control
information and specifications in addition to what is provided in this report may be found
in the current "Stormwater Management Manual for Western Washington," prepared by
Envirotech Engineering Geotechnical Investigation
Ph. 360-275-9374 page 13 Parcel 12305 1100040
Fax: 360-275-4789 Mason County,Washington
Jiilv 1. 2008
the Washington State Department of Ecology Water Quality Program.
4.4.4 Surface and Subsurface Drainage
Positive drainage should be provided in the final design for all planned residential
buildings. 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.
From a geotechnical perspective, both perimeter footing drains and roof drains are
optional for the single family residence. If roof drains are not utilized, splash blocks
should be placed at all downspouts. If footings are established at depths greater than 2
feet below final grade, then perimeter footing drains are recommended. If utilized,
subsurface water intercepted in the perimeter footing drains, and stormwater collected
from roof drains shall be tight-lined to an appropriate infiltration area or outlet protection
area located downslope and at least 10 feet from any structure. In addition, drainage
outlets shall not be within any of the recommended building setbacks or vegetation
buffers that are provided in this report.
4.4.5 Vegetation 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.
Although trees are limited for this Project, vegetation shall not be removed on the face of
the steep slope or within 50 feet from 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.
4.4.6 On-site and Off-site impacts
From a geotechnical position, it is Envirotech's opinion that the 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.
Envirotech Engineering Geotechnical Investigation
Ph. 360-275-9374 page 14 Parcel 12305 1100040
Fax: 360-275-4789 Mason County,Washington
Julv 1. 2008
4.5 Seismic Considerations and Liquefaction
Soils immediately below the expected foundation depth for this Project are generally Type D,
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 7 miles to the south of this Project.
This information is based on the USGS Quaternary Fault and Fold Database for the United States.
The potential for liquefaction and other earthquake induced hazards are believed to be low for
this Project. This is based, in part, on the slope stability analysis utilizing seismic considerations
in addition to 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. 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 Geotechnical Investigation
Ph. 360-275-9374 page 15 Parcel 12305 1100040
Fax: 360-275-4789 Mason County,Washington
July 1, 2008
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,
Envirotech Engineering
Michael Staten, P.E.
Geotechnical Engineer
Envirotech Engineering Geotechnical Investigation
Ph. 360-275-9374 page 16 Parcel 12305 1100040
Fax: 360-275-4789 Mason County,Washington
July 1, 2008
APPENDIX A
SITE PLAN
100F Tt
A. N
M SCALE, 1 INCH = 80 FEET
� 0
Tr
39
'P
T
'i
NOTES-
1. EROSION CONTROL MAY BE REQUIRED FOR THIS SITE,
GENERAL LOCATIONS, AND ALTERNATIVES TO SILT FENCES
MAY BE UTILIZED AS!EXPLAINED IN 'HE GEOTECHNICAL
REPORT. /-
2. CONTOURS WERE MOT PREPARED BY A LICENSED LAND
SURVEYOR, CONTOURS WERE EXTRAPOLATED FROM A PUBLIC
LIDAR SOURCE, AND INCORPORATED FIELD MEASUREMENTS AS
EXPLAINED IN THE GEOTECHNICAL REPORT.
N
+1 f Np\
r
n -
Zc
dlo
r�
�IL
7 ,Sof
I
EXISTING OBILE
HOME TO E
REMOVED P1 -'0�
F-
Da TING SEP TANK m
fU
EXISTING
CARPORT
STING TIC
ADFIE D
TP2 4 •*
200
PROJECT/ OWNER/ LOCATION
PROPOSED PROPOSED
SINGLE EPTIC SINGLE FAMILY RESIDENCE
FAMILY �+ TANK 180 1 1 p GEOTECHNICAL REPORT
RESIDENCI BILL AND MICHELLE KENNEDY
333FTt PARCEL 12329 22 00080
LEG ND MASON COUNTY, WASHINGTON
PROPOSED STRAW, IF
NECESSARY 11 ENGINEER,
PROPERTY +T+M=I N ENVIROTECH ENGINEERING
74 NE HURD ROAD
LINE
SLOPE DIRECTION BELFAIR, WASHINGTON 98528
eo EXISTING CONTOUR 360-275-9374
TPle TEST PIT SITE PLAN
APPENDIX B
GEOLOGIC MAP
100FTt
M N
a SCALE: 1 INCH = 100 FEET
� 9
8
260 \ \
M
f r
n Na M
,o Zc
�L
�L
240
SOILS, MODERATE DENSE SILTY SAND
WITH GRAVEL (SM) OVERLYING
DENSE WELL-GRADED SAND (SW)
EXISTING TRAILER TO BE REMOVED TP1
220 A o
m
(U
EXISTING CARPORT
PROPOSED
SINGLE
FAMILY
RESIDENCE
A
PROPERTY LINE
AND VEGETATION L if SLOE
DUFFER 1
140 120
180'
PROJECT/ OWNER/ LOCATION
APPROXIMATE
OCAINfTTOo TOP SINGLE FAMILY RESIDENCE
OF SLOPE GE❑TECHNICAL REPORT
BILL AND MICHELLE KENNEDY
PARCEL 12329 22 00080
LLEGEND MASON COUNTY, WASHINGTON
ENGINEER,
SET BACK ENVIROTECH ENGINEERING
NOTES- 74 NE HURD ROAD
IRECTD7N1. CONTOURS VERE NOT PREPARED BY A LICENSED LAND BELFAIR, WASHINGTON 98528SURVEYOR. CONTOURS WERE EXTRAPOLATED FROM A PUBLIC CONTOUR360-275-9374
LIDAR SOURCE, AND INCORPORATED FIELD MEASUREMENTS ASEXPLAINED IN THE GEOTECHNICAL REPORT. T GE❑L❑GIC MAP
APPENDIX C
SOIL INFORMATION
VERTICAL AND HORIZONTAL SCALE,
SCALES 1 INCH 80 FEET
0
PROPOSED HOUSE
MODERATE DENSE SILTY SAND
WITH GRAVEL (SM)
7%t
_a
DENSE WELL-GRADED
SAND WITH
GRAVEL(SW), AND SAND
27i*
6%t
SECTION AzA
PROJECT/ OWNER/ LOCATION,
SINGLE FAMILY RESIDENCE
GE❑TECHNICAL REPORT
BILL AND MICHELLE KENNEDY
PARCEL 12329 22 00080
MASON COUNTY, WASHINGTON
NOTES, ENGINEER,
ENVIROTECH ENGINEERING
1) MINOR GRADE CHANGES WILL BE COMPLETED IN ORDER 74 NE HURD ROAD
TO ACHIEVE POSITIVE DRAINAGE. BELFAIR, WASHINGTON 98528
2) THE SOIL PROFILE IS ACCURATE FOR THE DEPTH OF 360-275-9374
THE OBSERVED TEST PITS AT THE SPECIFIED LOCATIONS,
LOWER DEPTHS ARE BASED ON SITE GEOLOGY, SOIL PROFILE
WELL LOG(S), AND/OR EXPERIENCE IN THE GENERAL AREA.
TEST PIT LOG
TEST PIT NUMBER TP-1
PROJECT: Kennedy SFR Geotechnical Report DATE OF LOG: 06/17/2008
PROJECT NO: 0864 LOGGED BY: MCS
CLIENT: Bill Kennedy EXCAVATOR: N/A
LOCATION: Parcel 12329 22 00080 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
SM Brown, medium dense SILTY SAND with
GRAVEL. Low plasticity.
1
...........................................
SW Dense WELL-GRADED SAND with
gravel.
2
3
Excavation terminated at approximately
3.0 feet
4
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.
TEST PIT LOG
TEST PIT NUMBER TP-2
PROJECT: Kennedy SFR Geotechnical Report DATE OF LOG: 06/17/2008
PROJECT NO: 0864 LOGGED BY: MCS
CLIENT: Bill Kennedy EXCAVATOR: N/A
LOCATION: Parcel 12329 22 00080 DRILL RIG: None
Mason County, Washington ELEVATION: N/A
INITIAL DEPTH OF WATER: N/A FINAL DEPTH OF WATER: N/A
SOIL STRATA, STANDARD PENETRATION TEST
DEPTH SAMPLERS USCS DESCRIPTION LL PI CURVE
AND TEST DATA DEPTH N 10 30 50
0
SM Brown, medium dense SILTY SAND with
GRAVEL. Low plasticity.
1
..................................... .. ...
SW Dense WELL-GRADED SAND with
2 Excavation terminated at approximately
2.0 feet
3
4
5
6
7
8
9
10
No Groundwater Encountered ENVIROTECH ENGINEERING
This intormation pertains only to this boring and should not be Geotechnical Engineering
interpreted as being indicitive of the entire site.
Start Cord No. W/� 13066
De DeparOrigitment
of
lanaiCopywfth WATER WELL REPORT UMOUE WELL A 4 13
Deprtmervt of Ecology /�t �4 L
Second Copy-Owners Copy STATE OF WASHINGTON Y�
Third Copy-Driller's Copy Water Right Permit No.
p` (T) OWNER: Name Jeff Skoubo A,&. NE 50 Tima Rd Belfair WA 98528
C {�
NNW (2) LOCATION OF WELL: Coolly Mason - L\t•Y Alf7 1,4 NW 114 sac 29 T. 23 N-.R 1Ml W M.
IM
(?n) STREET ADDRESS OF WELL(orrleanwaddiese) NE 50 Tima Rd Belfair WA 98528
GJ
(3) PROPOSED USE: IV Domestic Indusfral :1 Municipal (10) WELL LOG or ABANDONMENT PROCEDURE DESCRIPTION
❑ IrriDe
a ter Formation.Describe color,character,size of material rid structure,and show thickness of aquifers
on
V) ❑ Dewater Test 1Ne11 ❑ Other f by q
and the ford and nature of kre maternal in each stratum penetrated,with al lsaat anti entry for each
r (4) TYPE OF WORK Owner's number of well change of Information.
(If more than one} MATERIAL FROM TO
O Abandoned New well K Method: Dug❑ Bored❑
Deepened ❑ Cabla19 Driven
OReconditioned ElRotary❑ Jefted D Sand & gravel0 15
= (5) DIMENMNS: Diametero►well_ 6 inches.
EDrlllad 155 feet. Depth of competed well - 155 it. Sand 15 50
0 (6) CONSTRUCTION DETAILS: Slue clay j 50 60
C Casing Installed: 6 Dam,from—_ff.to 155 --FL
Th' Installed rim n sand & avel_w't water 60 100
t
Pertonllons: Yes 0 No EX Fine sand with water 100 14
0 Type of perforator used
-o SIZE of peroratons in by "' Sand & gravel with water 140 155
C perforations from-_ ft.to IL --
R perforations from ft.to fL J—
perforations from it to_ h.
R -
So Sens: Yes ❑ No X7 -_
--
� Manufacturer's Name
4-1 Type - Model No.
�► Dram. _Slotelss --from--- ft to ff.
Dram. _Slat size from__ ff.to h.
` Gravel pecked: lies[ No[3 Size of gravel
3 Gravel placed from — h.to n. —
Surlace seal: Yes[ No❑ To what d@O7 h. -
O Material used in seal - _nni to
Z Did any straits contain unusable water+ YMs❑ No El -
N Type of water? Depth of strata _ —
h7J Method of sealing strata off
O
(7) PUMP: Manufacturers Name Goulds
Type: _ _ sub,
ZT
C (8) WATER LEVELS: hand mrfece sbvanon
Oabove mean sea ierel __-- ft
v Stair level 100 h below top of well Dap
LU Artesian pressure __-_... Ibs,per square Inch Onto
414- Artesar water a conlroletl by -._-.
Q (Cap. .air work Started .19 Complated 19
C (9) W ELL TESTS: Drawdown is amount water level is lowered below state level
Was a pump test made? Yes[ No® It yes,by whom? WELL CONSTRUCTOR CERTIFICATION:
EYlsld: _ get.;min.with N.drewdown after _M. I constructed and!or accept responsibility for construction of this well, and ils
L -- compliance With ail Washington well construction standards Materials used and
the iMorrnaLon reported above Ora true to my best knowledge and betiet.
CIL
Recovery data(time taken as Mo when pump turned of)(water laysl measured tram was NAME Davis IB Dr i llini
Q top to water l0l) —i0ERaON.nrM4 On RATIONI MrPIE On PRIMTI
a Time Water Lvval Time Water Level Time Water Leval
� Addre&s_ Belfair WA 98528 _
H- --�
lSbrted) L rtse No. _20
62
l E
Data of teat _
Boller test_ 10 gal.lmin.with_ 0 h.drawdown after _hire Contractor's
Registration
Airtest gaurnin.with stem twinat fLfor twill No. DAVISDI1100A Date _.10124M .19
Artesian flow ..g.p.m. Date
Temperature of water _Was a chemical analysis made? Yes ❑ No® (USE ADDITfONAL SHEETS IF NECESSARY)
ECLoso-1-dQt2n--r 0
APPENDIX D
SLOPE STABILITY
STABLE Slope Stability Analysis System
New User
Project : Kennedy
iatafile: dynamic Bishop
SOILS
SOIL NAME LINETYP£-'PEN COHESION FRICTION UNIT WT.
1 Soil-1 CONTINUOUS-BLACK 0.00 40.0 134.000
2 Soil-2 CONTINUOUS-BLUE 0.00 35.0 115.000
444}4a}444a444444444444444}}444444444444444444444444444444
PORE PRESSURE SPECIFICATION
SOIL PIEZO RU EXCESS
Y/N/P Value Value
i N 0.000 0.000
2 N 0.000 0.000
PIEZOMETRIC SURFACE
POINT
POINT PORE PRESSURES
POINT PRESSURE
4444444444}4444444}t}444444444444444444Y44t444444444444444 i
SLIP DIRECTION (+/- X) = +
444aa#a+t444t+4+444ta++4+++++++tta*+4+tray++t+t+44+t4taaat I
SLIP-CIRCLES
AUTOMATIC
Circle Centre Grid Extremities
704.000
88.000 * * 792.000
t++taaattt4aa++
0.000
X spacing -- no. of cols (max 10)= 10
Y spacing -- no. of rows (max 20)= 20
Grid 1 Circles through point 11
Grid 2 Circles through point 12
Grid 3 Circles through point 13
Grid 4 Circles through point 14
Grid 5 Circles through point 15
Grid 6 Circles through point 16
Grid 7 Circles through point 17
Grid 8 Circles through point 18
Grid 9 Circles through point 19
Grid 10 Circles through point 20
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APPENDIX E
EROSION CONTROL
GEOTEXTILE FABRIC 2'x2' WOOD POST (TYP) GEOTEXTILE FABRIC
WRAP AROUND TRENCH OR EQUIVALENT OR BETTER AND WIRE MESH
TO AT LEAST ENTIRE 2 6 FT MAX. O.C. 05 FT
BOTTOM (F TRENCH
BEFORE PLACING GRAVEL 2'x2'x5' WOOD POST OR — 6 FT
12' DEEP, 8' WIDE TRENCH EQUIVALENT OR BETTER EXISTING
FILLED WITH 3/4' TO 1 1/2) GROUND SURFACE
WASHED GRAVEL 2 T
DIRECTION OF r 2.5 FT 12' DEEP, 8' WIDE 1 7
DIRER FLOW EXISTING TRENCH FILLED WITH
12' GROUND SURFACE 3/4' TO 1 1/2' 2S FT
T2.5 FT WASHED GRAVEL
�g BOTTOM EXTENTS OF
GEOTEXTILE FABRIC SILT FENCE - DETAIL
:Lamm N.T.S.
N.T.S. PERMANENT EROSION CONTROL NOTES,
GENERAL NOTES- SOD PLACEMENT
1. SHOULD THE TEMPORARY EROSION AND SEDIMENT CONTROL MEASURES SHOWN ON 1. SOD FOR GRASS SWALES SHALL BE MACHINE CUT AT A
THESE PLANS PROVE TO BE INADEQUATE DURING CONSTRUCTION, THE CONTRACTOR 3/4-INCH UNIFORM THICKNESS AT THE TIME OF CURING.
SHALL INSTALL ADDITIONAL EROSION AND SEDIMENT CONTROL FACILITIES. MEASUREMENTS FOR THICKNESS SHALL EXCLUDE TOP GROWTH AND
2. ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE THATCH.
INSPECTED DAILY AND IMMEDIATELY MAINTAINED, IF NECESSARY. 2. STANDARD SIZE SECTIONS OF SOD FOR GRASS SWALES SHALL
3. ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE LEFT IN BE STRONG ENOUGH TO SUPPORT THEIR OVN WEIGHT AND RETAIN
PLACE UNTIL THE UPSLOPE AREAS HAVE BEEN PERMANENTLY STABILIZED. THEIR SIZE AND SHAPE WHEN SUSPENDED BY THE END OF A 3
TEMPORARY EROSION CONTROL NOTES, FOOT SECTION.
3. SOD FOR GRASS SWALES SHALL NOT BE HARVESTED OR
TRANSPLANTED WHEN EXCESSIVELY DRY OR WET MOISTURE
FOR ALL AREAS WHICH HAVE BEEN STRIPPED OF VEGETATION OR EXPERIENCED LAND CONTENT MAY ADVERSELY AFFECT ITS SURVIVAL.
DISTURBING ACTIVITIES, AND WHERE NO FURTHER WORK IS ANTICIPATED FOR A 4. SOD FOR GRASS SWALES SHALL BE HARVESTED, DELIVERED
PERIOD EXCEEDING THE LISTED CRITERIA BELOW, ALL DISTURBED AREAS MUST BE AND PLACED WITHIN A PERIOD OF 36 HOURS.
IMMEDIATELY STABILIZED WITH MULCHING, GRASS PLANTING OR OTHER APPROVED
EROSION CONTROL TREATMENT APPLICABLE TO THE TIME OF YEAR. GRASS SEEDING SEEDING FOR RAW SLOPES
ALONE WILL ONLY BE ACCEPTABLE DURING THE MONTHS OF APRIL THROUGH
SEPTEMBER, HOWEVER, SEEDING MAY PROCEED WHENEVER IT IS IN THE INTEREST OF 1. BEFORE SEEDING, INSTALL NEEDED SURFACE RUNOFF CONTROL
THE OWNER/CONTRACTOR, BUT MUST ALSO BE AUGMENTED WITH MULCHING, NETTING MEASURES SUCH AS GRADIENT TERRACES, INTERCEPTOR DIKES,
OR OTHER APPROVED TREATMENT. SWALES, LEVEL SPREADERS AND SEDIMENT BASINS.
2. THE SEED BED SHALL BE FIRM WITH FAIRLY FINE SURFACE,
DRY SEASON (MAY 1 THRU SEPTEMBER 30) -- THE CLEARING OF LAND, INCLUDING THE FOLLOWING SURFACE ROUGHENING. PERFORM ALL OPERATIONS
REMOVAL [IF EXISTING VEGETATION OR OTHER GROUND COVER, MUST BE LIMITED TO ACCROSS OR PERPENDICULAR TO THE SLOPE.
ONLY AS MUCH LAND AS CAN RECEIVE APPROPRIATE PROTECTIVE COVER OR BE 3. SEEDING RECOMMENDATIONS, AS SHOWN BELOW, AND SHOULD BE
OTHERWISE STABILIZED, AFTER HAVING BEEN CLEARED OR OTHERWISE DISTURBED , APPLIED AT THE RATE OF 120 POUNDS PER ACRE.
BY NO LATER THAN SEPTEMBER 30 OF A GIVEN YEAR. UNLESS IMMEDIATE 4. SEED BEDS PLANTED BETWEEN MAY 1 AND OCTOBER 31 WILL
STABILIZATION IS SPECIFIED IN THE EROSION AND SEDIMENT CONTROL PLAN, ALL REQUIRE IRRIGATION AND OTHER MAINTENANCE AS NECESSARY TO
AREAS CLEARED OR OTHERWISE DISTURBED MUST BE APPROPRIATELY STABILIZED FOSTER AND PROTECT THE ROOT STRUCTURE.
THROUGH THE USE OF MULCHING, NETTING, PLASTIC SHEETING, EROSION BLANKETS, 5. SEED BEDS PLANTED BETWEEN NOVEMBER 1 AND APRIL 30,
FREE DRAINING MATERIAL, ETC., BY SEPTEMBER 30 OR SOONER PER THE APPROVED ARMORING OF THE SEED BED WILL BE NECESSARY, (e.g.,
PLAN OF ACTION. UNLESS OTHERWISE APPROVED BY THE COUNTY, SEEDING, GEOTEXTILES, JUTE MAT, CLEAR PLASTIC COVERING).
FERTILIZING AND MULCHING OF CLEARED OR OTHERWISE DISTURBED AREAS SHALL BE 6. FERTILIZERS ARE TO BE USED ACCORDING TO SUPPLIERS'
PERFORMED DURING THE FOLLOWING PERIODS, MARCH I TO MAY 15, AND AUGUST 15 TO RECOMMENDATIONS. AMOUNTS SHOULD BE MINIMIZED, ESPECIALLY
OCTOBER 1. SEEDING AFTER OCTOBER 1 WILL BE DONE WHEN PHYSICAL COMPLETION ADJACENT TO WATER BODIES AND WETLANDS.
OF THE PROJECT IS IMMINENT AND THE ENVIROMENTAL CONDITIONS ARE CONDUCIVE
TO SATISFACTORY GROWTH IN THE EVENT THAT PERANENT STABILIZATION IS NOT USE THE FOLLOWING RECOMMENDED SEED MIXTURE FOR EROSION
POSSIBLE, AN ALTERNATIVE METHOD OF GROUND COVER, SUCH AS MULCHING, NETTING, CONTROL, OR A COUNTY APPROVED ALTERNATE SEED MIXTURE.
PLASTIC SHEETING, EROSION BLANKETS, ETC., MUST BE INSTALLED BY NO LATER THAN
SEPTEMBER 30. PROPORTIONS PURITY
GERMINATION
IN THE EVENT THAT CONSTRUCTION ACTIVITIES OR OTHER SITE DEVELOPMENT NAME BY WEIGHT (7) (%>
ACTIVITIES ARE DISCONTINUED FOR AT LEAST 4 CONSECUTIVE DAYS, THE (%)
OWNER/CONTRACTOR SHALL BE RESPONSIBLE FOR THE INSPECTION OF ALL EROSION
AND SEDIMENT CONTROL FACILITIES IMMEDIATELY AFTER STORM EVENTS, AND AT REDTOP (AGROSTIS ALBA) 10 92
LEAST ONCE EVERY WEEK. THE OWNER/ CONTRACTOR SHALL BE RESPONSIBLE FOR 90
THE MAINTENANCE AND REPAIR OF ALL EROSION AN SEDIMENT CONTROL FACILITIES. ANNUAL RYE (LO_IUM MULTIFLORUM) 40 98
90
WET SEASON (OCTOBER I THRU APRIL 30) -- ON SITES WHERE UNINTERUPTED CHEWING FESUE 40 97
CONSTRUCTION ACTIVITY IS IN PROGRESS, THE CLEARING OF LAND, INCLUDING THE 80
REMOVAL OF EXISTING VEGETATION AND OTHER GROUND COVER, SHALL BE LIMITED (FESTUCA RUBRA COMMUTATA>
TO AS MUCH LAND AREA AS CAN BE COVERED OR STABILIZED WITHIN 24 HOURS IN (JAMESTOWN, BANNER, SHADOW, KOKET)
THE EVENT A MAJOR STORM IS PREDICTED AND/ OR EROSION AND SEDIMENT WHITE DUTCH CLOVER 10 96
TRANSPORT OFF-SITE IS OBSERVED. 90
(TRIFOLIUM REPENS)
ALL CLEARED OR DISTURBED AREAS SHALL RECEIVE APPROPRIATE PROTECTIVE
COVER OR BE OTHERWISE STABILIZED, SUCH AS MULCHING, NETTING, PLASTIC MULCHING
SHEETING, EROSION BLANKETS, FREE DRAINING MATERIAL, ETC., WITHIN 5 DAYS AFTER
HAVING BEEN CLEARED OR OTHERWISE DISTURBED IF NOT BEING ACTIVELY WORKED. 1. MATERIALS USED FOR MULCHING ARE RECOMMENDED TO BE WOOD
SILT FENCING, SEDIMENT TRAPS, SEDIMENT PONDS, ETC., WILL NOT BE VIEWED AS FIBER CELLULOSE, AND SHOULD BE APPLIED AT A RATE OF 1000
ADEQUATE COVER IN AND OF THEMSELVES. IN THE EVENT THAT ANY LAND AREA NOT POUNDS PER ACRE.
BEING ACTIVELY WORKED REMAINS UNPROTECTED OR HAS NOT BEEN APPROPRIATELY 2. MULCH SHOULD BE APPLIED IN ALL AREAS WITH EXPOSED
STABILIZED 5 DAYS AFTER HAVING BEEN CLEARED, ALL CONSTRUCTION ACTIVITY ON SLOPES GREATER THAN 2-1 (HORIZONTAL,VERTICAL).
THE SITE, EXCEPT FOR APPROVED EROSION AND SEDIMENT CONTROL ACTIVITY, SHALL 3. MULCHING SHOULD BE USED IMMEDIATELY AFTER SEEDING OR IN
IMMEDIATELY CEASE UNTIL SUCH A TIME AS AFOREMENTIONED LAND AREA HAS BEEN AREAS WHICH CANNOT BE SEEDED BECAUSE OF THE SEASON. ALL
APPROPRIATELY PROTECTED OR STABILIZED. AREAS REQUIRING MULCH SHALL BE COVERED BY NOVEMBER 1.
SILT FENCE
PROJECT/ OWNER/ LOCATION,
1. GEOTEXTILE FILTER FABRIC TYPE SHALL BE PER SPECIFIED IN THE 'STORMWATER MANAGEMENT MANUAL SINGLE FAMILY RESIDENCE
FOR 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 BILL AND MICHELLE KENNEDY
TOGETHER ONLY AT A SUPPORT POST WITH A MINIMUM 6-INCH OVERLAP AND SECURELY FASTENED AT PARCEL 12329 22 00080
BOTH ENDS TO THE POST. MASON COUNTY, VASHINGTON
3. STANDARD FILTER FABRIC SHALL BE FASTENED USING 1' STAPLES OR TIE WIRES (HOG RINGS) P 4 IN
SPACING.
4. POSTS SHALL BE SPACED AND PLACED AT DEPTHS INDICATED IN THE DETAILS ON THIS SHEET, AND ENGINEERi
DRIVEN SECURELY INTO THE GROUND. ENVIROTECH ENGINEERING
5. WIRE MESH SHALL BE 2'X2'X14 GAUGE OR EQUIVALENT. THE WIRE MESH MAY BE ELIMINATED IF 74 NE HURD ROAD
EXTRA-STRENGTH FILTER FABRIC (MONOFILAMENT), AND CLOSER POST SPACING IS USED. BELFAIR, WASHINGTON 9B528
6. A TRENCH SHALL BE EXCAVATED ACCORDING TO THE DETAILS ON THIS SHEET ALONG THE LINE OF THE 360-275-9374
POSTS AND UPSLOPE FROM THE SILT FENCE.
7. SILT FENCES SHALL BE LOCATED DOWNSLOPE FROM THE CLEARING LIMITS OF THE PROJECT. EROSION CONTROL
Mason County Review Checklist
For a Geotechnical Report
Instructions:
This checklist is intended to assist Staff in the review of a Geotechnical Report. The Geotechnical Report
is reviewed for completeness with respect to the Resource Ordinance. If an item is found to be not
applicable, the Report should explain the basis for the conclusion. The Report is also reviewed for clarity
and consistency. If the drawings, discussion, or recommendations are not understandable, they should be
clarified. If they do not appear internally consistent or consistent with the application or observations on
site, this needs to be corrected or explained. If resolution is not achieved with the author, staff should
refer the case to the Planning Manager or Director.
Applicant's Name: Bill Kennedy_
Permit# BLD2008-01094 Parcel # 123292200080
Date(s) of the Document(s)reviewed: July 1, 2008
(1) (a)A discussion of general geologic conditions in the vicinity of the proposed development,
OK?—Yes Comment:
(b) A discussion of specific soil types
OK?—Yes Comment:
(c) A discussion of ground water conditions
OK?_Yes_Comment:
(d) A discussion of the upslope geomorphology
OK?_Yes_Comment:
(e) A discussion of the location of upland waterbodies and wetlands
OK?_Yes_Comment:
(f) A discussion of history of landslide activity in the activity in the vicinity, as available in the
referenced maps and records
OK? Yes_Comment:
(2) A site plan which identifies the important development and geologic features.
OK? Yes_Comment:
(3) Locations and logs of exploratory holes or probes.
OK? Yes_Comment:
(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.
OK? Yes_Comment:
(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.
OK? Yes_Comment:
(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.
OK? Yes Comment:
(7) (a)Appropriate restrictions on placement of drainage features
OK?_Yes_Comment:
(b) Appropriate restrictions on placement of septic drain fields
OK?_Yes_Comment:
(c) Appropriate restrictions on placement of compacted fills and footings
OK?_Yes_Comment:
(d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other
slopes on the property.
Page 1 of 2 Form Effective June 2008
OK? Yes_Comment:
(e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of
other slopes on the property.
OK? Yes_Comment:
(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.
OK? Yes 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 erosion, landslides and harmful construction methods.
OK? Yes_Comment:
(10) An analysis of both on-site and off-site impacts of the proposed development.
OK? Yes Comment:
(11) Specifications of final development conditions such as, vegetative management, drainage,
erosion control, and buffer widths.
OK? Yes_Comment:
(12) Recommendations for the preparation of structural mitigation or details of other proposed
mitigation.
OK?_N/A Comment: Not Applicable
(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.
OK? Yes Comment:
Are the Documents signed and stamped?_Yes_.
Type and #of License: _State of Washington (Professional Engineer#43045_
If not approved,what is the next action/recommendation for further action?
An internal review of the submitted Geo-Report was performed and completed on September 10, 2008
based on the Mason County Checklist for a Geo-Report and was found to address all of the necessary
criteria as stated in MC O 17.05. (1-13), and is therefore approved for its completeness.
Reviewed b , on_September 10, 2008_
Time spent in r iew: 1 h ur_
SECOND REVIEW/ UP TE
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