HomeMy WebLinkAboutGEO2018-00015 for BLD2018-00161 and BLD2018-00163 - GEO Geological Review - 11/16/2017 :✓OZDlB -QiUiUb l5
CO RECEIVED
6".ZD 18 W I La 3 MAY 0 8 2018
615 W. Alder Street
PLANNING
Geotechnical Report
for
Davis Garage and Pole Building
2361 E State Route 302, Belfair
Parcel No. 12216-21-90090
Mason County, Washington
November 16, 2017
Project#17185
Prepared For:
Shannon Davis
PO Box 3116 `\E� CLYbt
Belfair, Washington 98528
Prepared By:
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Envirotech Engineering, PLLC3�s-
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PO Box 984 1 I!16,'17
Belfair, Washington 98528
Phone: 360-275-9374
Mason County Department of Community Development
Submittal Checklist For a Geotechnical Resort
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 Shannon Davis Parcel# 12216-21-90090
Site Address 2361 E State Route 302, Belfair
(1) (a)A discussion of general geologic conditions in the vicinity of the proposed development,
Located on page(s) 5
(b) A discussion of specific soil types
Located on page(s) 7
(c) A discussion of ground water conditions
Located on page(s) 8
(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($) 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) 9
(2) A site plan which identifies the important development and geologic features.
Located on Map(s) Site Plan
(3) Locations and logs of exploratory holes or probes.
Located on Map(s) Site Plan/Soil Logs
(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) Site Plan
(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.
Located on Map(s) Soil Profile
(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.
Located on page(s) 11
(7) (a)Appropriate restrictions on placement of drainage features
Located on page(s) 18
(b) Appropriate restrictions on placement of septic drain fields
Located on page(s) 19
(c) Appropriate restrictions on placement of compacted fills and footings
Located on page(s) 14, 16
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.
Located on page(s) 19
(e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of
other slopes on the property.
Located on page(s) 17
(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) 19
(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.
Located on page(s) 11
(10) An analysis of both on-site and off-site impacts of the proposed development.
Located on page(s) 13
(11) Specifications of final development conditions such as, vegetative management, drainage,
erosion control, and buffer widths.
Located on page(s) 17-19
(12) Recommendations for the preparation of structural mitigation or details of other proposed
mitigation.
Located on page(s) 19
(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.
Located on Map(s) Site Plan
I, Michael C Staten hereby certify under penalty of
perjury that 1 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 conditions. I also certify that the Geotechnical
Report, dated 11/16/17 and entitled Davis
Garage and Pole Building meets all the requirements of the Mason
County Resource Ordinance, Landslide Hazard Section, is complete and true, 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)
C L)I.)F
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43045 .�� r
11/18/17
•S.S'/r�\1 1.�:��, .
Page 2 of 2 Form Effective June 2008
Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report.
Table of Contents
1.0 INTRODUCTION....................................................................................................................................................I
1.1 PROJECT INFORMATION...........................................................................................................................................1
1.2 PURPOSE OF INVESTIGATION AND SCOPE OF WORK..................................................................................................1
2.0 SURFACE CONDITIONS...................................
2.1 GENERAL OBSERVATIONS............................................................................................. 3
2.2 TOPOGRAPHY.........................................................................................................................................................3
2.2.1 Upslope Geomorphology..............................................................................................:...............................3
2.3 SURFACE DRAINAGE............................................................................................................................:................3
2.3.1 Upslope Water Bodies........................................................................................................ .. ................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........................................................................................................................7
3.3.1 Groundwater.................................................................................................................................................8
4.0 ENGINEERING ANALYSES AND CONCLUSIONS......................................................................I...................9
4.1 SLOPE STABILITY....................................................................................................................................................9
4.1.1 Slope Stability Analysis...............................................................................................................................11
4.2 EROSION...............................................................................................................................................................11
4.2.1 Shoreline Recession....................................................................................................................................12
4.3 SEISMIC CONSIDERATIONS AND LIQUEFACTION.....................................................................................................12
4.3.1 Liquefaction...............................................................................................................................................12
4.4 LANDSLIDE,EROSION AND SEISMIC HAZARDS CONCLUSIONS................................................................................12
4.5 LATERAL EARTH PRESSURES..........................................................................................................................I......12
4.6 ON-SITE AND OFF-SITE IMPACTS...........................................................................................................................13
5.0 ENGINEERING RECOMMENDATIONS...............,..........................................................................................14
5.1 BUILDING FOUNDATION RECOMMENDATIONS........................................................................................................14
5.1.1 Bearing Capacity........................................................................................................................................14
5.1.2 Settlement....................................................................................................................................................15
5.1.3 Concrete Slabs-on-Grade............................................................................................................................15
5.2 EARTHWORK CONSTRUCTION RECOMMENDATIONS...............................................................................................15
5.2.1 Excavation...................................................................................................................................................15
5.2.2 Placement and Compaction of Native Soils and Engineered Fill................................................................16
5.2.3 Retaining Wall BacV111...............................................................................................................................17
5.2.4 Wet Weather Considerations.......................................................................................................................17
5.2.5 Building Pads..............................................................................................................................................17
5.3 BUILDING AND FOOTING SETBACKS......................................................................................................................17
5.4 SURFACE AND SUBSURFACE DRAINAGE............................................................................................................I....18
5.5 VEGETATION BUFFER AND CONSIDERATIONS........................................................................................................19
5.6 TEMPORARY AND PERMANENT EROSION CONTROL................................................................................................19
5.7 SEPTIC DRAiNFIELDs.............................................................................................................................................19
5.8 STRUCTURAL MITIGATION....................................................................................................................................19
6.0 CLOSURE...............................................................................................................................................................20
Appendix A-Site Plan
Appendix B-Soil Information
Appendix C-Slope Stability
Appendix D—Erosion Control
Appendix E—Drainage Details
1.0 INTRODUCTION
Envirotech Engineering (Envirotech) has completed a geotechnical investigation for a planned
garage and pole building located at 2361 E State Route 302, identified as parcel number 12213-
21-90090, Mason County, Washington. See the vicinity map on the following page for a general
depiction of the site location.
An initial geotechnical evaluation of the Project was conducted by Envirotech on October 10,
2017. 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. Based on this site characteristic, 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 which, at a minimum,
conforms to the applicable MCRO.
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; supporting
documentation with relation to slope stability, erosion, seismic considerations, and lateral earth
pressures in the Engineering Analyses and Conclusions Section; and, recommendations for
foundation, settlement, earthwork construction, retainingwalls erosion control drainage, and
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vegetation in the Engineering Recommendations Section.
1.1 Project Information
Information pertaining to the planned development of the Project was provided by the proponent
of the property. The planned development consists of a new garage and pole building, and other
ancillary features typical of this type of development. 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;
• Conduct a site visit to document the site conditions that may influence the construction
and performance of the proposed improvements of the Project;
• 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
Envirotech Engineering,PLLC _ 2361 E State Route 302
PO Box 984 page I Parcel 12216-21-90090
Belfair. Washington 98528 Mason County,Washington
Ph. 360-275-9374 November 16,2017
references concerning slope stability, and review water well reports from existing wells
near the Project;
• Collect bulk samples,as applicable, 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.
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Vicinity Map from Mason County Website
Envirotech Engineering,PLLC 2361 E State Route 302
PO Box 984 page 2 Parcel 12216-21-90090
Belfair,Washington 98528 Mason County, Washington
Ph. 360-275-9374 November 16,2017
2.0 SURFACE CONDITIONS
Information pertaining to the existing surface conditions for the Project was gathered on October
10, 2017 by a representative with Envirotech. During the site visit, the type of geotechnical
investigation was assessed, site features were documented that may influence construction, and
site features were examined that may be influenced by construction. This Surface Conditions
Section provides information on general observations, vegetation, topography, drainage and
observed slope/ erosion conditions for the Project and surrounding areas that may impact the
Project.
2.1 General Observations
Currently, the property is developed as a single family residential parcel. Vegetation on and near
the Project consists primarily of firs,cedars,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 extrapolated from a public lidar source,
and incorporated observations and field measurements. Where necessary, slope verification
included measuring slope lengths and inclinations with a cloth tape and inclinometer. See the Site
Plan in Appendix A in this report for an illustration of general topography with respect to the
planned development.
Critical descending slopes, with grades exceeding 40% appear to be within 300 feet of the
planned development, The maximum critical slope is approximately 40%with a vertical relief of
about 36 feet.
Critical ascending slopes,with grades exceeding 40%appear to be within 300 feet of the planned
development. The maximum critical slope is approximately 40%with a vertical relief of about 35
feet.
2.2.1 Upslope Geomorphology
The upland area of the property and beyond is generally situated on a hillside of glacial
origin.
2.3 Surface Drainage
Excessive scour, erosion or other indications of past drainage problems were not observed within
the immediate vicinity of the planned development.
2.3.1 Upslope Water Bodies
There are no apparent water bodies or wetlands located upslope from the planned
development that would significantly influence the Project.
Envirotech Engineering,PLLC 2361 E State Route 302
PO Box 984 page 3 Parcel 12216-21-90090
Belfair, Washington 98528 Mason County, Washington
Ph. 360-275-9374 November 16.2017
1
2.4 Slope and Erosion Observations
The slope gradients 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.
Although some slope instability was observed within the vicinity of the property, these slope
instability indicators or other significant mass wasting on the property 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 Google Website
Envirotech Engineering,PLLC 2361 E State Route 302
PO Box 984 page 4 Parcel 12216-21-90090
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 November 16,2017
3.0 SUBSURFACE INVESTIGATION
Information on subsurface conditions pertaining to the Project was primarily gathered on October
10, 2017 by a representative with Envirotech. Applicable 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 B of this report includes pertinent
information on subsurface conditions for the Project, such as subsoil cross-section(s), test pit
log(s), and applicable water well report(s). Water well reports were utilized to estimate ground
water levels, and if sufficient, were used in identifying subsoil types. Applicable test pit locations
are depicted on the Site Plan 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 and/ or nearby banks extending to depths of up to 10 feet below the natural ground
surface. Information on subsurface conditions also included reviewing geological maps
representing the general vicinity of the project, and water well reports originating from nearby
properties.
Soil samples were not obtained from this project. 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 loose to medium dense soils in the upper 12 inches, and dense
soils from 12 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.
The "Geologic Map of the Belfair 7.5-minute Quadrangle, Mason, Kitsap and Pierce Counties,
Washington" by Michael Polenz, Katelin Alldritt, Nicholas J. Hehemann, Isablle Y. Sarikhan,
and Robert L.Logan,July 2009,provides the following caption(s)for the project area:
Vashon recessional lake-marginal outvash—Gravel.sand.
and locally fines: gray to brown: forded by prostuival reworking
of upslope units(usually ablation till)into a systematic
lake-marginal deltaic assemblage of fluvial beds near rite top.
foreset beds in the center. and quiet-water lake-bottorn beds at
the base: fines typically limited to the bottoinset beds. where
the unit grades laterally into unit Qgof. See Geologic Setting
for notes on unit thickness and distribution.
Envirotech Engineering,PLLC 2361 E State Route 302
PO Box 984 page 5 Parcel 12216-21-90090
Belfair, Washington 98528 Mason County,Washington
Ph. 360-275-9374 November 16,2017
E�il
flow
glacial ice-contact deposits—Saud.gravel.lodgment till.and
ow till:lililior Silt and clay beds:tan to gray: variably sorted: loose to
couipact. massive to well stratified: locally includes over-steepened beds
that typically reflect sub-ice flow.but their dip clay. along with
siiiall-scale shears.also have developed as collapse features or due to
glaciotectonic and tectonic deforivation: formed in the presence of
inelnvater alongside ice.generally toward the end of the glaciation. and is
thus eoiiunoniv acconipanied by stagnant-ice features. such as kettles and
less-orderly hnuinlocky topography. eskers (also separately inapped as
subunit Qge). and subglacial or subaerial oluwash chailuels. Deposits and
illoiphologies that support conceptual association with both ice and
ineltwater are coimiion hi the inap area and sluggest that where unit Qgic is
mapped in the presence of fluted topograply. it is couuuonly only a fete
feet thick and locally could have been napped as undifferentiated drill
(unit Q2d). Elsewhere. the unlit may be over 100 ft thick.Unit Qgic also
includes poorly consolidated till eoninionly accompanied by underlying.
angular salad acid noted as"sub-glacially reworked till" by-Laprade(200 3)
(see Geologic Setting).especially in fluted areas that lack dead-ice
feanires. See unit Qgo and Fig. 1 for discussion of similarities between
tinits Qgic and Qgo(and its subunits Qgos.Qgof. and Qgol).A
discrepancy between this map and the Vaughn quadrangle to the south
resulted where Logan and Walsh(2007)ulapped undifferentiated
Quaternaii,deposits(unlit Qu)because they lacked field exposilres and
aeonloiphic signs of the dead-ice deposits that are apparent north of the
boundaiv. Dead-ice topography, north of the boundary also reveals a sandy
deposit mapped as iiilit Qgos by Logan and tt alsh(2007) to be a facies
within unit Qgic. Locally divided into:
Envirotech Engineering,PLLC 2361 E State Route 302
PO Box 984 page 6 Parcel 12216-21-90090
Belfair,Washington 98528 Mason County, Washington
Ph. 360-275-9374 November 16,2017
QgOI
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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 Natural Resource Conservation Service(MRCS)descriptions.
The Project is currently composed of native soils without indications of borrowed fill. Within test
pit locations, soils within the upper 10 feet of natural ground were generally observed to be moist,
brown silty sand with some clay(SM). This is based on nearby well reports, site geology, and/or
knowledge of the general area.
The relative densities of the soil within selected test pits 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 B 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 Very Gravelly
Envirotech Engineering,PLLC 2361 E State Route 302
PO Box 984 page 7 Parcel 12216-21-90090
Belfair, Washington 98528 Mason County, Washington
Ph. 360-275-9374 November 16,2017
Sandy Loam, Eh, with 8% - 15% slopes, and Everett Very Gravelly Sandy Loam, Ek, with 15% -
30% slopes. The soil designations are depicted in the aerial photograph below, and descriptions
are provided in Appendix B of this report,
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Soil Survey From USDA Natural Resources Conservation Service
3.3.1 Groundwater
From the water well report(s)and knowledge of the general area, permanent groundwater
is at least 50 feet directly below the property at the building pad location. Surface seepage
or perched groundwater at shallow depths was not observed on-site, nor indicated on the
well reports.
Envirotech Engineering,PLLC 2361 E State Route 302
PO Box 984 page 8 Parcel 1 22 1 6-2 1-90090
Belfair,Washington 98528 Mason County, Washington
Ph. 360-275-9374 November 16,2017
4.0 ENGINEERING ANALYSES AND CONCLUSIONS
The following section includes slope stability, erosion, seismic considerations, and impacts to
both on-site and off-site properties.
4.1 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 with relation to current engineering protocol. 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, repeated surficial slope movements, if not repaired, may represent a threat to the
structural integrity of the slope. If any slope movement arises,the slope should be inspected by an
engineer. Subsequently,maintenance tnay 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' and `Intermediate' regarding potential landslide activity.
Descriptions of these mapping units may be found in the aforesaid Atlas. A Stability Map from
the Coastal Zone Atlas for the general area of this Project is provided below:
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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' relating to soils. DNR labeled
Envirotech Engineering,PLLC 2361 E State Route 302
PO Box 984 page 9 Parcel 12216-21-90090
Belfair,Washington 98528 Mason County. Washington
Ph. 360-275-9374 November 16.2017
portions of this project as medium and high slope instability with relation to slopes. A Resource
Map from the DNR Forest Practices Application Review System is provided below:
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SOILS—On Resource MAP onL
Hyd:ic Sorts
Egliy Unstable
HigWy Erodible
Figlily nstable&
..iahl%-Erodible
10 Data or Gravel
Pits
SLOPE—On Resource Map onh
Medium Slope
Instabilir,
_High Slq a Instability:
Envirotech Engineering,PLLC 2361 E State Route 302
PO Box 984 page 10 Parcel 12216-21-90090
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 November 16,2017
4.1.1 Slope Stability 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:
Upper 5 feet soil depth
Soil unit weight: 134 pcf
Angle of internal friction: 35 degrees
Cohesion: 0 psf
Based on the slope stability analysis, unacceptable factors of safety could be present on
and near the critical slope,but do not reflect conditions where development is expected to
occur. For this Project, at the location of the proposed development, minimum factor of
safeties for static and dynamic conditions were estimated to be 1.8 and 1.2, respectively.
See the slope stability information in Appendix C for a depiction of input parameters and
example of outputs.
4.2 Erosion
Based on the USCS description of the Project soils, the surface soils are considered moderately
erodible. According to the Resource Map from the Washington State DNR, as provided above,
the Project is not within terrain labeled `highly erodible.' This Project is not within an erosion
hazard area as defined by the MCRO. Erosion hazard areas are those with USDA NRCS
designations of River Wash (Ra), Coastal Beaches (Cg), Alderwood Gravelly Sandy Loam on
slopes 15% or greater (Ac and Ad), Cloquallum Silt Loam on slopes 15% or greater (Cd),
Harstine Gravelly Sandy Loam on slopes 15% or greater (Hb), and Kitsap Silt Loam on slopes
15% or greater(Kc).
It is our opinion that minor erosion control recommendations provided in this report is sufficient
for the development of this Project, and additional engineered erosion control plans are not
required. Temporary and permanent erosion control measures are 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.
The Temporary and Permanent Erosion Control Section (Section 5.6) of this report consist of
specific erosion controls to be implemented. Additional erosion control information and
Envirotech Engineering, PLLC 2361 E State Route 302
PO Box 984 page 1 I Parcel 12216-21-90090
Belfair. Washington 98528 Mason County, Washington
Ph. 360-275-9374 November 16,2017
specifications may be found in the latest addition of the "Stormwater Management Manual for
Western Washington," prepared by the Washington State Department of Ecology Water Quality
Program,
4.2.1 Shoreline Recession
The project is not located adjacent to a shoreline.
4.3 Seismic Considerations and Liquefaction
There are no known faults beneath this Project. The nearest Class `A' or Class `B' fault to this
property is the Sunset Beach Scarp, Tacoma Fault Zone, in which is approximately 1.8 miles to
the northwest of this Project. This information is based on the USGS Quaternary Fault and Fold
Database for the United States.
Potential landslides due to seismic hazards have been considered, and are addressed in the Slope
Stability Analysis Section provided earlier in this report.
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.
4.3.1 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.
4.4 Landslide,Erosion and Seismic Hazards Conclusions
DNR did not indicate historic landslide activity near the Project. Mapped slope conditions, as
delineated by the Departments of Ecology and/ or Natural Resources, were considered in our
slope stability assessment. Based on the proximity and severity of mapped delineations with
respect to the proposed development, results of the aforesaid slope stability analysis, observed
surface conditions, and other pertinent information, it is our opinion that the proposed
development may occur in accordance with the recommendations in this geotechnical report.
4.5 Lateral Earth Pressures
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
Envirotech Engineering,PLLC 2361 E State Route 302
PO Box 984 page 12 Parcel 1 22 1 6-2 1-90090
Belfair,Washington 98528 Mason County, Washington
Ph. 360-275-9374 November 16,2017
backfill compaction, slope of backfill, surcharges, hydrostatic pressures, earthquake pressures,
and the direction and distance that the top of the wall moves. Significant retaining structures are
not anticipated for this Project. If retaining walls are later planned for this Project, prescriptive
requirements from the County should be adhered to. For retaining structures with a height
exceeding County prescriptive requirements,
ments, additional designparameters must be accounted f
P or
in the retaining wall analysis, and recommendations should only be provided by a qualified
engineer after the e of backfill is acquired, inclination
type q nation of backfill slope is estimated and the
final wall height is determined.
4.6 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 opinion is based on the expected site
development, existing topography, existing nearby development, land cover, and adhering to the
recommendations presented in this report. Future development or land disturbing activities on
neighboring properties or properties beyond adjacent parcels that are upslope and/or downslope
from the subject property could cause problems to the subject property. For this reason, future
development or land disturbance near the subject property should be evaluated by a geotechnical
engineer.
Envirotech Engineering, PLLC 2361 E State Route 302
PO Box 984 page 13 Parcel 12216-21-90090
Belfair, Washington 98529 Mason Countv, Washington
Ph. 360-275-9374 November 16,2017
5.0 ENGINEERING RECOMMENDATIONS
The following sections present engineering 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; soil/
geologic conditions that were identified from the geotechnicai investigation that is summarized in
the Subsurface Investigation Section; and, Project research, analyses and conclusions as
determined in the Engineering Analysis and Conclusions Section. Recommendations for the
Project that is provided herein,includes pertinent information for building foundations,earthwork
construction, building and/or footing setbacks, drainage, vegetation considerations, and erosion
control.
5.1 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. Foundation parameters
provided herein account for typical structural pressures due to the planned type of development.
A structural analysis is beyond the scope of a geotechnical report, and a structural engineer may
be required to design specific foundations and other structural elements based on the soil
investigation.
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.
5.1.1 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 that is competent and unyielding. 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 continuous
footing width of 15 inches(15 inches for 2-story structures)shall be placed at a minimum
of 18 inches below the existing ground surface atop unyielding, undisturbed native soils.
For a columnar load of no more than 3 tons, a circular or square isolated foundation
diameter or width shall be at least 24 inches. Pole building foundations are to be a
minimum of 4 feet in depth. Foundation recommendations are made available based on
adherence to the remaining recommendations that are provided in this report. Alterations
Envirotech.Engineering,PLLC 2361 E State Route 302
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Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 November 16.2017
to the aforementioned foundation recommendations may be completed upon a site
inspection by a geotechnical engineer after the foundation excavation is completed.
5.1.2 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
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.
5.1.3 Concrete Slabs-on-Grade
Interior slabs, if utilized, should be supported on a minimum of 4 inches of compacted
coarse, granular material (Retained on U.S. Sieve 410 or greater) that is placed over
undisturbed, competent native subgrade or engineered fill per the Earthwork
Recommendations Section below.
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
this report, concrete slabs should also be designed for structural integrity and
environmental reliability. This includes vapor barriers or moisture control for mitigating
excessive moisture in the building.
5.2 Earthwork Construction Recommendations
Founding material for building foundations shall consist of undisturbed native soils to the
specified foundation depths. 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.
5.2.1 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, not as described in this report, 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.
Envirotech Engineering, PLLC i 2361 E State Route 302
PO Box 984 page 15
Parcel 1 22 1 6-2 1-90090
Belfair, Washington 98528 Mason County,Washington
Ph. 360-275-9374 November 16,2017
5.2.2 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 horizontal foot for each foot of compacted or re-compacted fill depth beneath the
foundation. See the illustration below.
--FOOTING
COMPACTED
NATIVE SOILS
OR ENGINEERED / I
FILL
I
UNDISTURBED SUBGRA E
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. Because of
moisture sensitivity, importing and compacting engineered fill may be more economical
than compacting disturbed native soils. Engineered fill shall include having the soils
retained on the No. 4 sieve crushed (angular), and should consist of the following
gradation:
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 6 inches for both 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. Permanent cut
and fill slopes shall be limited to a slope of 2:1, unless otherwise approved by an
engineer.
Envirotech Engineering, PLLC 2361 E State Route 302
PO Box 984 page 16 Parcel 12216-21-90090
Belfair, Washington 98528 Mason County, Washington
Ph. 360-275-9374 November 16,2017
5.2.3 Retaining Wall Backfill
As previously mentioned, significant retaining structures are not anticipated for this
Project. However, if used, native soils may be used as retaining wall backfill for this
Project. Backfill may also consist of engineered fill or borrow materials approved by a
geotechnical engineer. Placement, compaction and extents of retaining wall backfill
should also be specified by a geotechnical engineer or qualified professional.
5.2.4 Wet Weather Considerations
Due to the types of subsurface soils, additional provisions may be required during
prolonged wet weather. Every precaution should be made in order to prevent free
moisture from saturating the soils within excavations. If the bottom of excavations used
for footing placement changes from a moist and dense/hard characteristic as presented in
this report to muck or soft, saturated conditions, then these soils become unsuitable for
foundation bearing material. If this situation occurs, a geotechnical engineer should be
notified, and these soils should be completely removed and replaced with compacted
engineered fill or suitable native material as presented in this section.
5.2.5 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. Building fill pad depth should
be limited to no more than 3 feet for this project.
5.3 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 40 feet footing
setback from the face of the nearby descending slopes exceeding 40%. See the figure below and
the Site Plan in Appendix A for an illustration of the setbacks.
Envirotech Engineering,PLLC 2361 E State Route 302
PO Box 984 page 17 Parcel 12216-21-90090
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 November 16,2017
S-R r ;RE
S pl - S� 1=E
.-_r.__....
SETBA:K
From the illustration above, structures may be located closer to the top of slope by extending the
foundation deep enough to maintain the recommended setback. In addition, the required setback
may be reduced by mitigation, and subsequently would require additional geotechnical studies.
Due to potential debris flow, the building location should have a minimum setback from the local
ascending slope toe equal to the slope height. The toe of the ascending slope is delineated as a
grade break in which the ascending slope is in excess of 40%.Envirotech recommends the garage
setback to be at least 15 feet from the toe of the nearby ascending slope. See the Site Map in
Appendix B for an illustration of the setbacks. The setback for ascending slopes may be reduced
by utilizing a catchment wall between the building and ascending slope. Alternatively, the
catchment wall may be incorporated into the structure.
5.4 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 immediately. 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. Leakage of water pipes, both
drainage and supply lines, shall be prevented at all times.
If impervious thresholds are exceeded per Mason County code, then engineered stormwater
management plans are required for this project. The drainage engineer must coordinate with a
geotechnical engineer for input with relation to slope stability prior to submitting drainage plans.
If stormwater management plans are not required for this project, then the following
recommendations should be followed.
Both footing perimeter drains and roof drains are required for this Project. Subsurface water
intercepted in the footing perimeter drains, and stormwater collected from roof drains shall be
separately tight-lined to the recommended outlet. Roof and foundation drains may share a
tightline if an above ground drainage outlet is allowable and a backflow preventer is installed
within the pipe system in order to prevent roof water from entering the foundation area.
For this project, we recommend that roof downspout dispersion is used in lieu of infiltration.
Each splash block should receive runoff from no more than 700 sf of roof area. Recommended
drainage details are provided in Appendix E of this report.
Envirotech Engineering,PLLC 2361 E State Route 302
PO Box 984 page 18 Parcel 12216-21-90090
Belfair, Washington 98528 Mason County,Washington
Ph. 360-275-9374 November 16.2017
5.5 Vegetation Buffer and Considerations
For this project, we believe that a detailed clearing and grading plan is not warranted unless
Mason County thresholds are exceeded, and basic vegetation management practices should be
adhered to.
Vegetation Buffer—Vegetation shall not be removed from the face of the critical slope or within
a distance of 30 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 Site Plan in Appendix A of this report for a depiction of
the vegetation buffer.
5.6 Temporary and Permanent Erosion Control
Erosion control during construction should include minimizing the removal of vegetation to the
least extent possible. Erosion control measures during construction may include stockpiling
cleared vegetation, silt fencing, intercepting swales, berms, straw bales, plastic cover or other
standard controls. Although other controls may be used, if adequate, 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 D 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 as 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 D. 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.
5.7 Septic Drainfields
The approximate location of the existing 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 critical slopes. This
is also based on compliance with all recommendations in this report.
5.8 Structural Mitigation
With respect to landslide alleviation or slope improvements, structural mitigation is not necessary
for this project. This determination is based on the anticipated improvements of the project,
engineering conclusions,and compliance with all recommendations provided in this report.
Envirotech Engineering, PLLC 2361 E State Route 302
PO Box 984 page 19 Parcel 12216-21-90090
Beifair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 November 16,2017
6.0 CLOSURE
Based on the project information provided by the owner, the proposed development, 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. It is not recommended that a
qualified engineer performs a site inspection during earthwork construction unless fill soils will
influence the impending foundation. However,if native,undisturbed subsurface conditions found
on-site are not as presented in this report,then a geotechnical engineer should be consulted.
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 potentially protect life and/or property. Semantics such as `suggested' or
`optional' refer that the associated design or specification may or may not be performed, but is
provided for optimal performance. 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 neighboring properties, changes to ordinances or regulatory
codes, or broadening of accepted geotechnical standards may affect the long-term 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
xu0)
Robert McNearny,E.I.T. Michael Staten,P.E.
Staff Engineer Geotechnical Engineer
Envirotech Engineering,PLLC 2361 E State Route 302
PO Box 984 page 20 Parcel 1 22 1 6-2 1-90090
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 November 16,2017
APPENDIX A
SITE PLAN
�—EXISTING SEPTIC EXISTING STRUCTURE
DRAINF;IELD AREA
318±
SCALE: 1"=80'
10' CUT BANK
EXISTING DRIV W �Y h , �"407 0 20 40 80
TO BE REPLACES 1� / EXISTING DRIVEWAY
S' ELEVATION R❑- j
i
A /..
PROP❑SED DRIVEWAY
TPl
i C
f o
PROPOSED STRUCTURE
TOPE OF
SLOPE I TOP OF SLOPE EXCEEDING
EXCEEDING �% 407
40"/. I f 340± PROPERTY LINE
TOE ❑1 - I
SLOPE 1, I _ 40' CONSTRUCTI❑N SETBACK
EXCEEDING - FR❑M TOP OF' SLOPE
40% - 30' VEGETATED BUFFER
FROM TOP OF SLOPE
f
J- - TOE OF SLOPE EXCEEDING
I f I 40% 1-0
I I lb' CONSTRUCTION SETBACK
I '
�40Y FROM TOE OF SLOPE
SILTFE cE --% ,
PROPOSED DRIVEWAY J
PROPOSED STRUCTURE -
NOTES,
PROJECT/ OWNER/ LOCATION,
1. EROSION CONTROL MAY BE REQUIRED FOR THIS SITE, GENERAL LOCATIONS SINGLE FAMILY RESIDENCE
ARE DEPICTED, AND ALTERNATIVES MAY BE UTILIZED AS EXPLAINED IN THE GEOTECHNICAL REPORT GEOTECHNICAL REPORT
.
2. CONTOURS WERE NOT PREPARED BY A LICENSED LAND SURVEYOR. DAVIS
CONTOURS WERE EXTRAPOLATED FROM A PUBLIC LIDAR SOURCE, AND 2361 E STATE ROUTE 302
INCORPORATED FIELD MEASUREMENTS AS EXPLAINED IN THE GEOTECHNICAL LEGEND PARCEL 12216-21-90090
REPORT. MASON COUNTY WASHINGTON
3. BOUNDARIES WERE NOT PREPARED BY A LICENSED SURVEYOR. LOCATIONS ENGINEER,
OF SITE FEATURES THAT ARE SHOWN HERE, SUCH AS TOP OF SLOPES, TOE EROSION CONTROL EN TEMPORARY ENGGINEER, ENGINEERING
OF SLOPES, WATER FEATURES, ETC,,, WITH RELATION TO THE PROPERTY
LINES MUST BE VERIFIED BY THE OWNER. RECOMMENDATIONS IN THE SLOPE INDICATOR PO BOX 984
GEOTECHNICAL REPORT PROVIDE SETBACKS, BUFFERS, DEPTHS, ETC.. WITH BELFAIR, WASHINGTON 99528
RELATION TO GEOLOGIC FEATURES, NOT PROPERTY LINES. THESE GEOLOGIC EXISTING CONTOUR 360-275-9374
FEATURES MAY BE LOCATED ON THE SUBJECT PROPERTY OR NEIGHBORING T P TEST PIT PROPERTIES. SITE PLAN
APPENDIX B
SOIL INFORMATION
SCALE: 1"=40'
0 10 20 40
EXISTING GRADE
EXISTING HOUSE
EXISTING GRADE
/ EXISTING GRADE
SILTY SAND (SM) 20;--�
W/ CLAY
SECTION A-A
PROJECT/ OWNER/ LOCATION,
SINGLE FAMILY RESIDENCE
GEOTECHNICAL REPORT
DAVIS
2361 E STATE ROUTE 302
PARCEL 12216-21-90090
NOTES MASON COUNTY, WASHINGTON
ENGINEER,
1) MINOR GRADE CHANGES REQUIRED IN ORDER TO ACHIEVE ENVIROTECH ENGINEERING
POSITIVE DRAINAGE PO BOX 984
2) THE SOIL PROFILE IS ACCURATE FOR THE DEPTH OF BELFAIR, 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. S❑IL PROFILE
TEST PIT LOG
TEST PIT NUMBER TP-1
PROJECT. Davis Geotechnical Report DATE OF LOG: 10/10/17
PROJECT NO: 17185 LOGGED BY: MCS
CLIENT: Shannon Davis EXCAVATOR: N/A
LOCATION: Parcel 12216-21-90090 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 DEPTH N CURVE
AND TEST DATA 10 30 50
. . . . . . . .. . . . . . .
SM Brown, moist, loose to medium dense
SILTY SAND with CLAY. Sand is mostly
medium. Medium plasticity.
1
2
3
i 4 -
5 7.
6
7
8
9
110
Excavation terminated at approximately
pP Y
10.0 feet
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.
Map Unit Description:Everett very gravelly sandy loam,15 to 30 percent slopes--Mason
County,Washington
Mason County, Washington
Ek—Everett very gravelly sandy loam, 15 to 30 percent
slopes
Map Unit Setting
National map unit symbol: 2t62c
Elevation: 30 to 900 feet
Mean annual precipitation: 35 to 91 inches
Mean annual air temperature: 48 to 52 degrees F
Frost-free period. 180 to 240 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Everett and similar soils: 80 percent
Minor components. 20 percent
Estimates are based on observations, descriptions, and transects of
the mapunit.
Description of Everett
Setting
Landform: Karnes, eskers, moraines
Landform position (two-dimensional): Backslope
Landform position (three-dimensional): Side slope
Down-slope shape: Convex
Across-slope shape: Convex
Parent material: Sandy and gravelly glacial outwash
Typical profile
Oi- 0 to 1 inches: slightly decomposed plant material
A - 1 to 3 inches: very gravelly sandy loam
Bw-3 to 24 inches: very gravelly sandy loam
C1 -24 to 35 inches: very gravelly loamy sand
C2-35 to 60 inches: extremely cobbly coarse sand
Properties and qualities
Slope: 15 to 30 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Somewhat excessively drained
Capacity of the most limiting layer to transmit water(Ksat): High
(1.98 to 5.95 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available waterstorage in protrle: Low(about 3.2 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification(nonirrigated): 4e
Hydrologic Soil Group: A
LsDA Natural Resources Web Soil Survey 11/7/2017
:� Conservation Service National Cooperative Soil Survey Page 1 of 2
Map Unit Description:Everett very gravelly sandy loam, 15 to 30 percent slopes—Mason
County,Washington
Other vegetative classification: Droughty Soils(G002XN402WA),
Droughty Soils (G002XS401 WA)
Hydric soil rating: No
Minor Components
Alderwood
Percent of map unit., 10 percent
Landform: Ridges, hills
Landform position (two-dimensional): Backslope
Landform position (three-dimensional): Side slope, nose slope, talf
Down-slope shape: Linear, convex
Across-slope shape: Convex
Hydric soil rating: No
Indianola
Percent of map unit: 10 percent
Landform: Eskers, karnes, terraces
Landform position (two-dimensional): Backslope
Landform position (three-dimensional): Side slope
Down-slope shape: Linear
Across-slope shape: Linear
Hydric soil rating: No
Data Source Information
Soil Survey Area: Mason County, Washington
Survey Area Data: Version 13, Sep 7, 2017
Natural Resources Web Soil Survey 11n12017
Conservation Service National Cooperative Soil Survey Page 2 of 2
Please print, sign and return to the Department of Ecology
Water Well Report Current
Original —Ecology, leSto owner,2ndeo driller Notice of Intent No.W 186124
,rnn IC gy, py— py—
EC0LOgsY
C...... etion/Decommission Unique Ecology Well ID Tag No. rA r 4S3
E]Construction Water Right Permit No.
❑ Decommission ORIGINAL INSTALLATION Noilce Property Owner Name A & M t1pwP1 pment
� ojlnie)rt Number(j Well Street Address_Lbqy 302
PROPOSED USE: RI Domestic Industrial ❑ Municipal City Reuel f air County_��
❑DeWater ❑Irrigation Test Well ❑Other
LocationNEI/4-1/4 NW1/4 Sea 6 Twn�R1 ewtr crck
TYPE OF WORK: Owner's number of well(if more than one) W WM are
Ncw well ❑Reconditioned Alcihud.❑Dug ❑ Bored ❑ Driven Lat/Lon s, r Lat De Lat Min/Sec
Deepened [RCabic ❑Rotary ❑Jetted g L tg
DIMENSIONS: Diameter of well_(}_inches.drilled_233,1. still REQUIRED) Long Deg Long Min/Sec
Depth of completed well 233 ft.
CONSTRUCTION DETAILS Tax Parcel No.12216-21-90070
Casing E]Welded 6 Diam.from _R.to _ft.
Installed: n Liner installed Dian.from ft.to ft. CONSTRUCTION OR DECOMMISSION PROCEDURE
❑Threaded Diam.from R.to P..
Perforations: CI Yes No Formation: Describe by:olor,character,size of material and structure,and the kind and
nature of the material in each stratum penetrated,with al least one entry for each change of
Type of perforator used 'information indicate all water encountered. (USE ADDITIONAL SHEETS IF NECESSARY.
SIZE of perfs_in.by—in.and no.of perfs_from_A.to_ft. MATERIAL FROM TO
Screens: [RYes ❑No 4K•Pac Location 225
Manufacturer's Name John-an
Type Model No.
Diam. __ of size from-fl.to— �_R.
Diam. Slot size from—ft.to ft. Gray clay with sand grBve 10
CravellFlter packed:❑Yes jpNo [:]Size of gravellsand
Materials placed from ft.to ft.
Surface Seal::Z Yes ❑No To what depth'? 18 fl.
Material used in seal Pkat-cm i f-A
Did any strata contain unusable water'? ❑Yes j]No
Type of water? Depth of strata Blue clay with gravel
Method of scaling strata off
Pump; Manufacturer's Name_C.011—
TYpe: sub H.P. i
WATER LEVELS: Land-surface elevation above mean sea level—ft. Blue Cla With sand & grave
Static level ft.below top of well Date
Artesian pressure lbs.per square inch Date
Artesian water is controlled by Cementet3 Silt a SaI'2d 21
free valve,etc.)
228
WELL TESTS: Drowdown is amount water level is lowered below static level
Was a pump test made'?❑Yes R No If ves,by whom? Gray
Yield: gal./min.with fl.drawdown after hrs.
Yield: galJmin,with R.drawdown after hrs.
Yield: ealJmin.with ft.drawdown after hrs.
Recovery duru(time taken ns zero when pimp turned of/)(%tier level mearured from well
top to water level)
Time Water Level Time Water Level Time Water Level
Date of test
Halter test'0 rat./min.with 25 ft.drawdown after�hn. 1 n Q�i
Airtest golJmin,with stem set at R.for hrs. C8 vJ
Artesian now u.p.m. Date
Temperature of water Was a chemical analysis made? ❑Yes KI No
Start Date Completed Date
__QtJ_30jjQC
WELL CONSTRUCTION CERTIFICATION: I constructed and/or accept responsibility for construction of this well,and its compliance with all
Washington Well construction standards. Materials used and the information reported above are true to my best knowledge and belief,
Driller/Engineer/Trainee Name(P Drilling Company
DrilleriEngineerffrainee signatur Address 340 NP FIR - E'a_jd
Driller or trainee License No. qr,7 City,State,Zip Belfai r.IQ 9AS 8
I(TRAINEE. Contractor's
Driller's Licensed No. Registration No. ]gDjI I MQ Dale Sept.* 05
Driller's Signature Ecology is an Equal Opportunity Employer. ECY 050-1.20(Rev 2/03)
Please print, sign and return to the Department of Ecology
WeII Report Current
:olov', I"copy-owner,2ad copy-driller Notice of Intent No.W 186124
fission Unique Ecology Well ID Tag No. Art; 4 5 3__
Water Right Permit No.
2/GINAL!AIST,4LLATION Notice Property Owner Name A & M Deval QrMnt
Intent Number
Well Street Address M&W 302
:estic ❑ Industrial ❑ Municipal arion ❑Test Well ❑Other City pal fa yr County �Nta'c n�_
Location I�I/4-1/4 NW1/4 Sea 6 Twn,22 R1 E , circle
mber of well(if more thun one) WWM are
bfethud.❑Dug ❑ Bored ❑ Driven Lat/Lon t r Lat De Lat Min/See
IRCable ❑Rotary ❑Jetted Lat/Long ' ' g
11 6 inches,drilled_233 R. still REQUIRED) Long Deg Long Min/Sec
:red wen 21.3 A.
Tax Parcel No.12216-21-90070
Diam.from � ft.to�_ft.
Diann.from a.to ft. CONSTRUCTION OR DECOMMISSION PROCEDURE
Diam.From ft.to fl.
Formation: DescrU by rolor,character,size of material and structure,and the kind and
nature of the material in each stratum penetrated,with at least one entry for each change of
information indidale all water encountered. (USE ADDITIONAL SHEETS IF NECESSARY.
n.and no.of perfs_,_from_ft.to_A. MATERIAL FROM TO
, ❑,K•PLocationacLocation �Location 5,
4K-P^^
Model No.
from -i-in �ft.to _ft.
from ft.to ft. Gray clay W•th sand gr&ve 10 is
W No ❑Sir of gravclJsand
ft.to ft.
To what depth? 118
ri i t-a
aterf ❑Yes j]No
Depth of strata Blue clay with gravel
-GGUI &— H.P. T_
:elevation above mean sea level ft. Blue clay With sand & mave
_ft.below trap of well Date
lbs.per square inch Date
Cementted silt a sand 215 228
(cap,vane,etc.)
Count water level is lowered below static level
W No If yes,by whom•.' a
A.drawdown after hrs.
ft.drawdown after hrs.
ft.drawdown after hrs.
when pump turned a10(water lewd measured from will
to Water Level Time Water Level
h 5 ft.druwdown after hrs.
stem set at fi.for hrs. rtwEC8 i7J .
r.p.m. Date
is a chemical analysis made? ❑Yes FLI No
Start Date 917jr1r, Completed Date
CERTIFICATION: I constructed and/or accept responsibility for construction of this well,and its compliance with all
,n standards. Materials used and the information reported above are true to my best knowledge and belief.
Drilling Company
Address 340 ice: llavi S t'asm RrW
7 City,State,Zip Be fai„* WA C)81; a
'Contractor's
Registration No.D-AV'M13 I GOA_ Date C" _II5_
Ecology is an Equal Opportunity Employer, ECY 050-11-20(Rey 2103)
APPENDIX C
SLOPE STABILITY
STABLE Slope Stability Analysis System
New User
Project : Davis
Datafile: Dynamic Bishop
STABLE Version 9.03.00u
Bishop
TITLE
Dynamic
UNITS (Metric/Imperial) = I
GEOMETRY DEFINITION
POINTS
NO. X Y
1 0.000 0.000
2 50.000 0.000
3 140.000 -36.000
4 245.000 -58.000
5 335.000 -94.000
6 365.000 -94.000
7 36.500 0.000
8 51.870 -0.750
9 67.240 -6.890
10 82.610 -13.040
11 97.970 -19.190
12 113.340 -25.340
13 128.710 -31.480
14 144.080 -36.850
15 159.450 -40.070
16 174.820 -43.290
17 190.180 -46.510
18 205.550 -49.730
19 220.920 -52.950
20 236.290 -56.170
21 251.660 -60.660
22 267.030 -66.810
23 282.390 -72.960
24 297.760 -79.110
25 313.130 -85.250
26 328.500 -91.400
LINES
Lo X Hi X SOIL
1 2 1
2 3 1
3 4 1
4 5 1
5 6 1
SOILS
SOIL NAME LINETYPE-PEN COHESION FRICTION UNIT WT.
1 SM CONTINUOUS-BLACK 0.00 35.0 134.000
STABLEM002 MZAssociates Ltd Printed on: 16/11/17 @ 09:39:08 Page: 1
STABLE Slope Stability Analysis System
New User
Project : Davis
Dataf Ile: Dynamic Bishop
?ORE PRESSURE SPECIFICATION
SOIL PIEZO RU EXCESS
Y/N/P Value Value
1 N 0.000 0.000
PIEZOMETRIC SURFACE
POINT
POINT PORE PRESSURES
POINT PRESSURE
SLIP DIRECTION (+/- X) _ +
x+#>++;a;axx+##aa*♦+*+>taa+#;a♦#t++x*+xt*a#*xax;+*>++*+*a+
SLIP-CIRCLES
AUTOMATIC
Circle Centre Grid Extremities
292.000
;
36.500 * * 328.500
0.000
X spacing -- no. of cols (max 10)- 10
Y spacing -- no. of rows (max 20)- 20
Grid 1 Circles through point 7
Grid 2 Circles through point 8
Grid 3 Circles through point 9
Grid 4 Circles through point 10
Grid 5 Circles through point 11
Grid 6 Circles through point 12
Grid 7 Circles through point 13
Grid 8 Circles through point 14
Grid 9 Circles through point 15
Grid 10 Circles through point 16
Grid 11 Circles through point 17
Grid 12 Circles through point 18
Grid 13 Circles through point 19
Grid 14 Circles through point 20
Grid 15 Circles through point 21
Grid 16 Circles through point 22
Grid 17 Circles through point 23
Grid 18 Circles through point 24
Grid 19 Circles through point 25
STABLE02002 MZ Associates Ltd Printed on: 16/11/17 @ 09:39:08 Page: 2
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APPENDIX D
EROSION CONTROL
GEOTEXTILE FABRIC GEOTEXTILE FABRIC
BET
WRAP AROUND TRENCH 2•x2 WOOD POST AND WIRE MESH
TO AT LEAST ENTIRE OR EQUIVALENT OR BETTER
BOTTOM OF TRENCH 2 6 FT MAX. O.C. 6 FT -1 � 0,5 FT
BEFORE PLACING GRAVEL 2'x2'x5' WOOD POST OR
12' DEEP, 8' WIDE TRENCH EQUIVALENT OR BETTER EXISTING
FILLED WITH 3/4' TO 1 1/2' GROUND SURFACE
WASHED GRAVEL or VEGETAT N 2 T
DIRECTION OF 2'5�Fi 12' DEEP, 8' WIDE
WATER FLOW 1 EXISTING TRENCH FILLED WITH 1 T
12' GROUND SURFACE 3/4' TO 1 1/2` 2.5 FT
{ 2,S�FT WASHED GRAVEL OR
VEGETATION
__._g•f BOTTOM EXTENTS OF SILT FENCE - DETAIL
GEOTEXTILE FABRIC
SILT FENCE - CR SS SECTION N.T.S.
N.T.S. HAY OR STRAW MATTING
GENERAL 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
THESE 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
INSPECTED DAILY AND IMMEDIATELY MAINTAINED, IF NECESSARY. DOWN.
3. ALL EROSION AND ggSEDIEMENT COONTROL FACILITIES AND DEVICES SHALL BE LEFT IN
EMPORUNTIARY ER HE UPC�OTROLRNOTESAVE BEEN PERMANENTLY STABILIZED, PERMANENT EROSION CONTROL NOTES:
OR ALL AREAS WHICH HAVE BEEN STRIPPED OF VEGETATION OR EXPERIENCED LAND SEEDING FOR RAW SLOPES
ISTURBING ACTIVITIES, AND WHERE NO FURTHER WORK IS ANTICIPATED FOR A 1. BEFORE SEEDING, INSTALL NEEDED SURFACE RUNOFF CONTROL
ERIOD EXCEEDING THE LISTED CRITERIA BELOW, ALL DISTURBED AREAS MUST BE MEASURES SUCH AS GRADIENT TERRACES, INTERCEPTOR DIKES,
MMEDIATELY STABILIZED WITH MULCHING, GRASS PLANTING OR OTHER APPROVED SWALES, LEVEL SPREADERS AND SEDIMENT BASINS.
ROSION CONTROL TREATMENT APPLICABLE TO THE TIME OF YEAR, GRASS SEEDING 2. THE SEED BED SHALL BE FIRM WITH FAIRLY FINE SURFACE,
%LONE WILL ONLY BE ACCEPTABLE DURING THE MONTHS OF APRIL THROUGH FOLLOWING SURFACE ROUGHENING. PERFORM ALL OPERATIONS ACCROSS
EPTEMBER, HOWEVER, SEEDING MAY PROCEED WHENEVER IT IS IN THE INTEREST OF OR PERPENDICULAR TO THE SLOPE.
HE OWNER/CONTRACTOR, BUT MUST ALSO BE AUGMENTED WITH MULCHING, NETTING 3. SEEDING RECOMMENDATIONS, AS SHOWN BELOW, AND SHOULD BE
R OTHER APPROVED TREATMENT, APPLIED AT THE RATE OF 120 POUNDS PER ACRE.
RY SEASON (MAY 1 THRU SEPTEMBER 30) -- THE CLEARING OF LAND, INCLUDING THE 4. SEED BEDS PLANTED BETWEEN MAY 1 AND OCTOBER 31 WILL
REQUIRE IRRIGATION AND OTHER MAINTENANCE AS NECESSARY TO
EMOVAL OF EXISTING VEGETATION OR OTHER GROUND COVER, MUST BE LIMITED TO
FOSTER AND PROTECT THE ROOT STRUCTURE.
NLY AS MUCH LAND AS CAN RECEIVE APPROPRIATE PROTECTIVE COVER OR BE
THERWISE STABILIZED, AFTER HAVING BEEN CLEARED OR OTHERWISE DISTURBED , 5. SEED BEDS PLANTED BETWEEN N BE NE ER 1 AND APRIL 30,
Y NO LATER THAN SEPTEMBER 30 OF A GIVEN YEAR. UNLESS IMMEDIATE GEOTEARMORING OF THE SEED BED WILL BE NECESSARY, Ce.g.,
TABILIZATION IS SPECIFIED IN THE EROSION AND SEDIMENT CONTROL PLAN, ALL 6. FER FERTILIZERS
JUTE MAT, CLEAR PLASTIC COVERING).
REAS CLEARED OR OTHERWISE DISTURBED MUST BE APPROPRIATELY STABILIZED 6. FERTILIZERS ARE TO BE USED ACCORDING IZ SUPPLIERS'
HROUGH THE USE OF MULCHING, NETTING, PLASTIC SHEETING, EROSION BLANKETS, RECOMMENDATIONS, AMOUNTS SHOULD T MINIMIZED, ESPECIALLY
REE DRAINING MATERIAL, ETC„ BY SEPTEMBER 30 OR SOONER PER THE APPROVED ADJACENT TO WATER BODIES AND WETLANDS.
LAN OF ACTION. UNLESS OTHERWISE APPROVED BY THE COUNTY, SEEDING, USE THE FOLLOWING RECOMMENDED SEED MIXTURE FOR EROSION
ERTILIZING AND MULCHING OF CLEARED OR OTHERWISE DISTURBED AREAS SHALL BE CONTROL, OR A COUNTY APPROVED ALTERNATE SEED MIXTURE.
ERFORMED DURING THE FOLLOWING PERIODS, MARCH 1 TO MAY 15, AND AUGUST 15 TO
CTOBER 1. SEEDING AFTER OCTOBER 1 WILL BE DONE WHEN PHYSICAL COMPLETION PROPORTIONS PURITY GERMINATION
F THE PROJECT IS IMMINENT AND THE ENVIROMENTAL CONDITIONS ARE CONDUCIVE NAME BY WEIGHT(%) (%) (%)
0 SATISFACTORY GROWTH. IN THE EVENT THAT PERANENT STABILIZATION IS NOT
OSSIBLE, AN ALTERNATIVE METHOD OF GROUND COVER, SUCH AS MULCHING, NETTING, REDTOP (AGROSTIS ALBA) 10 92 90
LASTIC SHEETING, EROSION BLANKETS, ETC., MUST BE INSTALLED BY NO LATER THAN ANNUAL RYE (LOLIUM MULTIFLORUM) 40 98 90
EPTEMBER 30, CHEWING FESUE 40 97 80
FESTUCAN THE EVENT THAT CONSTRUCTION ACTIVITIES OR OTHER SITE DEVELOPMENT (JAMESTO RUBRA COMMUHADO
CTIVITIES ARE DISCONTINUED FOR AT LEAST 4 CONSECUTIVE DAYS, THE WHITE
BANNER, SHADOW, KOKET)
WNER/CONTRACTOR SHALL BE RESPONSIBLE FOR THE INSPECTION OF ALL EROSION WHITE DUTCH CLOVER 10 96 90
(TRIFDLIUM REPENS)
ND SEDIMENT CONTROL FACILITIES IMME➢IATELY AFTER STORM EVENTS, AND AT
EAST ONCE EVERY WEEK. THE OWNER/ CONTRACTOR SHALL BE RESPONSIBLE FOR MULCHING
HE MAINTENANCE AND REPAIR OF ALL EROSION AN SEDIMENT CONTROL FACILITIES.
ET SEASON (OCTOBER 1 THRU APRIL 30) -- ON SITES WHERE UNINTERUPTED 1. MATERIALS USED FOR MULCHING ARE RECOMMENDED TO BE WOOD
FIBER CELLULOSE, AND SHOULD BE APPLIED AT A RATE OF 1000
ONSTRUCTION ACTIVITY IS IN PROGRESS, THE CLEARING OF LAND, INCLUDING THE
REMOVAL OF EXISTING VEGETATION AND OTHER GROUND COVER, SHALL BE LIMITED POUNDS PER ACRE,
0 AS MUCH LAND AREA AS CAN BE COVERED OR STABILIZED WITHIN 24 HOURS IN 2, MULCH SHOULD BE APPLIED IN ALL AREAS WITH EXPOSED SLOPES
HE EVENT A MAJOR STORM IS PREDICTED AND/ OR EROSION AND SEDIMENT GREATER THAN SHOULD
(HORIZONTAL-VERTICAL).
ITEL
TRANSPORT OFF-SITE IS OBSERVED, 3. MULCHING SHOULD BE USED IMMEDIATELY AFTER SEEDING OR IN
AREAS WHICH CANNOT BE SEEDED BECAUSE OF THE SEASON, ALL
LL CLEARED OR DISTURBED AREAS SHALL RECEIVE APPROPRIATE PROTECTIVE AREAS REQUIRING MULCH SHALL BE COVERED BY NOVEMBER 1.
OVER OR BE OTHERWISE STABILIZED, SUCH AS MULCHING, NETTING, PLASTIC
MEETING, EROSION BLANKETS, FREE DRAINING MATERIAL, ETC., WITHIN 5 DAYS AFTER
AVING BEEN CLEARED OR OTHERWISE 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.
ILT 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 GE❑TECHNICAL REPORT
EACH BARRIER TO AVOID USE OF JOINTS. IF JOINTS ARE NECESSARY, FILTER FABRIC SHALL BE SPLICED DAVIS
TOGETHER ONLY AT A SUPPORT POST WITH A MINIMUM 6-INCH OVERLAP AND SECURELY FASTENED AT 2361 E STATE ROUTE 302
BOTH ENDS TO THE POST. PARCEL 12216-21-90090
3. STANDARD FILTER FABRIC SHALL BE FASTENED USING 1' STAPLES OR TIE WIRES (HOG RINGS) 2 4 IN MASON COUNTY, WASHINGTON
SPACING.
4, POSTS SHALL BE SPACED AND PLACED AT DEPTHS INDICATED IN THE DETAILS ON THIS SHEET, AND ENGINEER
DRIVEN SECURELY INTO THE GROUND, ENVIROTECH ENGINEERING
. WIRE MESH SHALL BE 2'X2'XI4 GAUGE OR EQUIVILENT. THE WIRE MESH MAY BE ELIMINATED IF PO BOX 984
EXTRA-STRENGTH FILTER FABRIC (MONOFILAMENT), AND CLOSER POST SPACING IS USED. BELFAIR, WASHINGTON 98528
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. ER❑SI❑N CONTROL
APPENDIX E
DRAINAGE DETAILS
r
BUILDING
ROOF DOWNSPOUT
SERVES UP T❑
700 SF OF ROOF
50 FT MIN
VEGETATED
FLOW PATH
DOWNSPOUT
EXTENSION
ROOF D❑WNSPOUT AND SPLASH BL❑CK DETAILS
N.T.S.
PROJECT/ OWNER/ LOCATION,
SINGLE FAMILY RESIDENCE
GE❑TECHNICAL REPORT
DAVIS
2361 E STATE ROUTE 302
PARCEL 12216-21-90090
MASON COUNTY, WASHINGTON
ENGINEER,
ENVIROTECH ENGINEERING
PO BOX 984
BELFAIR, WASHINGTON 98528
360-275-9374
DRAINAGE DETAILS
i
PROVED
APPUCANT �\ I I I I AP
DAVIS,SHANNON L d DANELLE RAE \ 1 I I �0 U NTY DEG
SITE ADDRESS LEGEND j \ 1 I I MASON
2361 E.STATE ROUTE 302 -! + 1- .I 1 111"-
7
SELF WA.98528 PROPOSED STRUCTURES 1(, 1 - I a� I
pLC.RE
SITE INFO -1 \ I P1 80 I- CMANgES SUBJECTiT0. . . R Y. rI
TAX PARCEL NUMBER:1221S-21-90090 ODSTRTG HOUSE .1' ._ \� I 1 I .�)
LEGAL DESCRIPTION ). �' .[_ate
TA 9 OF GOUT TAT I,1E68URV NT9 TR C OF V EX6TNC POND t ..�I i._ � .i ' _ I_ P4 i . . . . . . .
9P t99A PCL I OF BU R&O F61 M S 4MI DUSTING WAVE RDIO E1051MG . . ..1.'.�
EXISTING ASPMLT DFIRMY ml PARCEL'\NUMBER: 1 21B-21-90D901
FENCE \ I ABOVE GR01`ND POOL 1 I. . . . . I . . . . . ...
- PROPERTY LINE _ 1 SEP I 1 42%30 CARA .I _
- - . . . . 1
CENTER OF ROADWAY DVERHEAD I �70 mw 11 I .. '1, I 1
CONTOUR LINES PORER I r_,..._ .1.._"� •-•I(
PROPERTY INFO l BLDG.OUTLINE
SETBACK REOUIREMENTS
SIDES-5FT/FRONT 20FT/REAR IOFT DRAINAGE DZTNG GRAVEL ROAD __
EXISTING LOT INFO _______ SETBACK UNES I I 1 \ Yfl� /A' _ I I .
EXISTING STRUCTURE SINGLE STORY-]600 S.F. SILT FENCE(IF REQUIRED) I I., 1/F 4V I 1 2.�y� )
$.A-S.B FENCE(IF REQUIRED) i I lJ�/
0 LOT CORNER (, ..I
DISTURBED AREA BLDG CORNER .-- I 1 PC
LOT -174,210- ♦ACRES D C) I I J -
E%ISTMG STRUCTURE - 3800 S.F. GAS METER M I - -
GRAVEL DRIVEWAY 5187 S.F. WATER METER
TOTAL EXISTING MPERNOUS 8787 S F.
LOTOWER POLE
SF /1742w S.F.SF. Q :I ,I P2 1 .1. . . . I . . .
TOTAL IMPERVIOUS-5% CD CLEAN OUTS I'; I 1 .1. .. 1 O
■ DOWN SPOUTS
POLE BARN- 2OX42-924 S.F. -w w WATER LINE uj 4 I I 1 I 1
GARAGE-3OX42-12W S.F. SEWER LINE 67�.0�1 1 �\
TOTAL IMPERVIOUS MTH PROPOSED STRUCTURE _ OVERHEAD POWER I L \
8787+924+1260-10971 S.F. _-OHP_- GAS HEA
LINE
CD gG,p',1 '\ 42X20 POIE BARN I I �� \\ M1�b. O TYPE I C.B.W/CLEANOUT
EXISTING TREES `ON W REMODEL
prp
LOT -174240 S.F.-4 ACRES 1 I d 9���Ii1 r i I p Lo
DISTURBED AREA-109745F. -6.7'A l nI I
UNDISTURBED AREA-163269 S.F.-93.3%
.--I 1 1 �V P3
I 1 CP6)
\
1 1
LF 7 �T ��/II�� /J \
"'STING TREES TO REMAIN ( I A//1•02 1 W Ci
PC
NO TREE ARE TO BE REMOVED FROM THE SITE I 1 I I ( 1 ) \\
GARAGE
VICINITY MAP- NOT TO SCALE ARIEL VIE"- OT TO POLE BARNISCAL
..T+Ir : Y
P LA N N t Pan a
1 ! A l
• h,1- 'I .C•1`MAif kWI,F fW INn N
ALL SETBACKS ARE MEASURED i I '5*0, 1 a c SI TE PLAN
FROM THE FURTHEST
PROJECTION OF THE BUILDIN(' ► t - o
PRINT TO SCALE- USE 24X36
�►► ' , v � tea` �F` � O�c��..
Su�w18�rL O 12361 W4aMng10n 30! . Q�\'� - .�•- -._1 , � ���/d �" � ��
GEO wO - 6M L
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:// Y--, of S p
Permit#: l� j I Z. Parcel#:// 17
Date(s)of the Document(s) reviewed: V
1. (a) A discussion of general geologic conditions in the vicinity of the proposed development,
OK? _Comment:
(b) A discussio of specific soil types
OK? _Comment:
(c) A discussion
of ground water conditions
OK? Comment:
(d) A discussion of the upslope geomorphology
OK? Comment:
(e) A discussion of the location of upland waterbodies and wetlands
OK? Comment:
(f) A discussion of history of landslide activity in the vicinity, as available in the referenced maps and records
OK? _Comment:
2. A site plan that identifies the important development and geologic features.
OK? Comment:
3. Locations and logs of exploratory holes or probes.
OK? 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? Comment:
5. A minimum of one cross section at a scale which adequately depicts the subsurface profile, and which
incorpo ates the details of proposed grade changes.
OK? 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 oeffients should be a value of 0.15.
OK? 1 Comment:
7. (a) Appropriate restrictions on placement of drainage features
OK?_ �Comment:
(b) Appropriate restrictions on placement of septic drain fields
OK? Comment:
(c) Appropria estrictions on placement of compacted fills and footings.
OK? Comment:
Page 1 of 2 Form Effective June 2008
(d) RecomrrA.Ved buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes.
OK? Comment:
(e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes.
OK? 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? 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 onstruction methods.
OK? Comment:
10. An analysi5 of both on-site and off-site impacts of the proposed development.
OK?-� Comment:
11. Specifications of final development conditions such as, vegetative management, drainage, erosion control, and
buffer id s.
OK? Comment:
12. Recom e ations for the preparation of structural mitigation or details of other proposed mitigation.
OK? Comment:
13. A site map drawn to scale showing the property boundaries, scale, north arrow, and the location and nature of
existing proposed development on the site.
OK? Comment:
Are the Documents
?signed and stamped? By whom?
License#: `� ) (�`�S License type: /dr
FIRST REVIEW Approved ❑ Need more info.
If not approved, what is the next action/recommendation for further action?
Reviewed by /ram'—� on 1./ !1 Time spent in review: ] iy�,.
SECOND REVIEW/ UPDATE ❑ Approved ❑ Need more info.
Reviewed by on . Time spent in second review:
THIRD REVIEW/ UPDATE ❑ Approved ❑ Need more info.
Reviewed by on . Time spent in third review:
Disclaimer.' Mason County does not certify the quality of the work done in this Geotechnical Report.
Page 2 of 2 Form Effective June 2008