HomeMy WebLinkAboutGEO2019-00045 for BLD2019-00531 - BLD Engineering / Geo-tech Reports - 4/14/2019 Id Z-6Iq - I
RECEIVED
M 7m9
Geotechnical Report PLANNING
for
Manke Residential Structure
851 E State Route 106, Belfair
Parcel No. 32235-32-00041
Mason County, Washington
April 14, 2019
Project#1904
Prepared For:
Eric Manke
1717 Marine View Dr
Tacoma, WA 98424
Prepared By:
Envirotech Engineering
PO Box 984
Belfair, Washington 98528
Phone: 360-275-9374
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4/14/19
MASON COUNTY
COMMUNITY SERVICES Geotechnical Report
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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 is found not applicable,the report should explain the basis for the conclusion.
Note: Unless specifically documented, this report does not provide compliance to the International Residential
Code Sections R403.1.7 for foundations on or adjacent to slopes, Section R403.1.8 for expansive soils or section
1808.7.1 of the International Building Code Section for Foundations on or adjacent to slopes.
Applicant/Owner Eric Manke Parcel# 32235-32-00041
Site Address XXX E State Route 106
(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) 6
(c) A discussion of ground water conditions,
Located on page(s) 7
(d) A discussion of the upslope geomorphology,
Located on page(s) 3
(e) A discussion of the location of upland waterbodies and wetlands,
Located on page(s) 3
(f) A discussion of history of landslide activity in the vicinity,as available in the referenced maps and
records.
Located on page(s) 8
(2) A site plan which identifies the important development and geologic features.
Located on Map(s) Site Plan—Appendix A
(3) Locations and logs of exploratory holes or probes.
Located on Map(s) Site Plan and Soil Logs(Appendix B)
(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(Appendix B)
(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 coefficients should be a value of 0.15.
I
Located on page(s) 9- 10
Page 1 of 40
(7) (a) Appropriate restrictions on placement of drainage features,
Located on page(s) 15-16
(b) Appropriate restrictions on placement of septic drain fields,
Located on page(s) 17
(c) Appropriate restrictions on placement of compacted fills and footings,
Located on page(s) 13- 14
(d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes.
Located on page(s) 15
(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) 16
(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) 16
(10) An analysis of both on-site and off-site impacts of the proposed development.
Located on page(s) 11
(11) Specifications of final development conditions such as,vegetative management,drainage,erosion control,and
buffer widths.
Located on page(s) 15- 17
(12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation.
Located on page(s) 17
(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 Staten, hereby certify under penalty of perjury that I am a civil engineer licensed in the State of Washington
with specialized knowledge of geotechnical/geological engineering or a geologist or engineering geologist licensed in
the State of Washington with special knowledge of the local conditions. I also certify that the Geotechnical
CtydZ s Report,dated April 14,2019, and entitled Manke Residential
Structure, meets all the requirements of the Mason County
1 Resource Ordinance,Geologically Hazardous Areas Section,
is complete and true,that the assessment demonstrates
43045 conclusively that the risks posed by the landslide hazard can
I- <�l6R� r
f,S' Is be mitigated through the included geotechnical design
4/14/19 recommendations,and that all hazards are mitigated in such a
Disclaimer:Mason County does not manner as to prevent harm to property and public health and
certify the quality of the work done in safety.
this Geotechnical Report.
Page 2 of 2
TABLE OF CONTENTS
1.0 INTRODUCTION....................................................................................ERROR!BOOKMARK NOT DEFINED.
1.1 PROJECT INFORMATION.................................................................................ERROR!BOOKMARK NOT DEFINED.
1.2 PURPOSE OF INVESTIGATION AND SCOPE OF WORK.......................................ERROR!BOOKMARK NOT DEFINED.
2.0 SURFACE CONDITIONS......................................................................ERROR!BOOKMARK NOT DEFINED.
2.1 GENERAL OBSERVATIONS...............................................................................ERROR!BOOKMARK NOT DEFINED.
2.2 TOPOGRAPHY..................................................................................................ERROR!BOOKMARK NOT DEFINED.
2.2.1 Upslope Geomorphology..............................................................................Error!Bookmark not defined.
2.3 SURFACE DRAINAGE.......................................................................................ERROR!BOOKMARK NOT DEFINED.
2.3.1 Upslope Water Bodies...................................................................................Error!Bookmark not defined.
2.4 SLOPE AND EROSION OBSERVATIONS.............................................................ERROR!BOOKMARK NOT DEFINED.
3.0 SUBSURFACE INVESTIGATION........................................................ERROR!BOOKMARK NOT DEFINED.
3.1 FIELD METHODS,SAMPLING AND FIELD TESTING.........................................ERROR!BOOKMARK NOT DEFINED.
3.2 GENERAL GEOLOGIC CONDITIONS.................................................................ERROR!BOOKMARK NOT DEFINED.
3.3 SPECIFIC SUBSURFACE CONDITIONS...............................................................ERROR!BOOKMARK NOT DEFINED.
3.3.1 Groundwater.................................................................................................Error!Bookmark not defined.
4.0 ENGINEERING ANALYSES AND CONCLUSIONS.........................ERROR!BOOKMARK NOT DEFINED.
4.1 SLOPE STABILITY............................................................................................ERROR!BOOKMARK NOT DEFINED.
4.1.1 Slope Stability Analysis................................................................................Error!Bookmark not defined.
4.2 EROSION..........................................................................................................ERROR!BOOKMARK NOT DEFINED.
4.2.1 Shoreline Recession......................................................................................Error!Bookmark not defined.
4.3 SEISMIC CONSIDERATIONS AND LIQUEFACTION.............................................ERROR!BOOKMARK NOT DEFINED.
4.3.1 Liquefaction..................................................................................................Error!Bookmark not defined.
4.4 LANDSLIDE,EROSION AND SEISMIC HAZARDS CONCLUSIONS.......................ERROR!BOOKMARK NOT DEFINED.
4.5 LATERAL EARTH PRESSURES..........................................................................ERROR!BOOKMARK NOT DEFINED.
4.6 ON-SITE AND OFF-SITE IMPACTS...................................................................ERROR!BOOKMARK NOT DEFINED.
5.0 ENGINEERING RECOMMENDATIONS...........................................ERROR!BOOKMARK NOT DEFINED.
5.1 BUILDING FOUNDATION RECOMMENDATIONS................................................ERROR!BOOKMARK NOT DEFINED.
5.1.1 Bearing Capacity..........................................................................................Error!Bookmark not defined.
5.1.2 Settlement......................................................................................................Error!Bookmark not defined.
5.1.3 Concrete Slabs-on-Grade.............................................................................Error!Bookmark not defined.
5.2 EARTHWORK CONSTRUCTION RECOMMENDATIONS......................................ERROR!BOOKMARK NOT DEFINED.
5.2.1 Excavation....................................................................................................Error!Bookmark not defined.
5.2.2 Placement and Compaction of Native Soils and Engineered Fill...............Error!Bookmark not defined.
5.2.3 Retaining Wall Backfrll................................................................................Error!Bookmark not defined.
5.2.4 Wet Weather Considerations........................................................................Error!Bookmark not defined.
5.2.5 Building Pads................................................................................................Error!Bookmark not defined.
5.3 BUILDING AND FOOTING SETBACKS...............................................................ERROR!BOOKMARK NOT DEFINED.
5.4 SURFACE AND SUBSURFACE DRAINAGE..........................................................ERROR!BOOKMARK NOT DEFINED.
5.5 VEGETATION BUFFER AND CONSIDERATIONS................................................ERROR BOOKMARK NOT DEFINED.
5.6 TEMPORARY AND PERMANENT EROSION CONTROL.......................................ERROR!BOOKMARK NOT DEFINED.
5.7 SEPTIC DRAmFIELDS......................................................................................ERROR!BOOKMARK NOT DEFINED.
5.8 STRUCTURAL MITIGATION.............................................................................ERROR!BOOKMARK NOT DEFINED.
6.0 CLOSURE................................................................................................ERROR!BOOKMARK NOT DEFINED.
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
single family residence located at XXX E State Route 106,identified as parcel number 32235-32-
00041, 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 January 10,
2019.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) 8.52.140. 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, retaining walls, erosion control, drainage, and
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 1- or 2-story single family residential
structure 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
Envirotech Engineering Geotechnical Report
PO Box 984 page 1 Parcel 32235-32-00041
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 April 14,2019
and/ or cut banks, review geological maps for the general area, research published
references concerning slope stability, and review water well reports from existing wells
near the project;
• Collect bulk samples,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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Envirotech Engineering Geotechnical Report
PO Box 984 page 2 Parcel 32235-32-00041
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 April 14,2019
2.0 SURFACE CONDITIONS
Information pertaining to the existing surface conditions for the project was gathered on January
10, 2019 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 vacant with an existing septic and small shed that will be removed.
Vegetation on and near the project consists primarily of secondary growth cedars, hemlock, 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 ascending slopes with grades exceeding 40% appear to be within 300 feet of the planned
development. The critical slopes are located to the south east of the project site. The maximum
critical descending slope is approximately 78%with a vertical relief of over 190 feet.
Critical descending slopes are not located in the vicinity of the planned development.
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
Runoff originating upslope of the development is mostly diverted away from the property by
accommodating topography. Some surface water runoff was observed during the initial site visit.
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 Geotechnical Report
PO Box 984 page 3 Parcel 32235-32-00041
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 April 14,2019
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 of calving.
Bowing and leaning trees were observed on the critical slope. Other slope instability indicators or
signs of 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, 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 Report
PO Box 984 page 4 Parcel 32235-32-00041
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 April 14,2019
3.0 SUBSURFACE INVESTIGATION
Information on subsurface conditions pertaining to the project was primarily gathered on January
10, and March 28, 2019 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 medium dense soils in the upper 24 inches, and medium
consistency clay soils from 24 inches to the depth of terminus.
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 and glacial drift deposits.
The"Geologic Map of the Skokomish Valley and Union 7.5-minute Quadrangles,Mason County,
Washington' by Michael Polenz, Jessica L. Czajkowski, Gabriel Legorreta Paulin, Trevor A.
Conteras, Brendon A. Miller, Maria E. Martin, Timothy J. Walsh, Robert L. Logan, Robert J.
Carson, Chris N. Johnson, Rian H. Skov, Shannon A. Mahan, and Cody R. Cohan, June 2010,
provides the following caption(s)for the project area:
Alluvium fan deposits--Cobbles.pebbles.sand,silt.and boulders.poorly sorted and stratified:
forms concentric lobes where streams emerge from valleys:relict where Qoat.
Pre-Fraser northern-source outwAsh--Cobble to pebble gravel with sandy to clayey matrix:
QP° reddish brown:compact:clasts well rounded and well sorted:eery thinly to very thickly bedded
Envirotech Engineering Geotechnical Report
PO Box 984 page 5 Parcel 32235-32-00041
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 April 14,2019
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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 Soil Conservation Service(SCS)descriptions.
The project is currently composed of native soils with some indications of fill. Within the
exposed 10 feet of test pit,soils were generally observed to be brown silty sand with gravel(SM),
overlying sandy clay with gravel (SC). These sediments extend vertically to a depth of up to 50
feet. This information is based on nearby well reports, site geology, and/ or knowledge of the
general area.
The relative densities of the soil within selected test area 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 Alderwood gravelly sandy
loam, Ad, with 30% - 50% slopes, and Everett very gravelly sandy loam, En, with 8% - 15%
Envirotech Engineering Geotechnical Report
PO Box 984 page 6 Parcel 32235-32-00041
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 April 14,2019
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 40 feet directly below the property at the building pad location. Perched groundwater at
shallow depths was not observed on-site, nor indicated on the well reports. Surface water was
observed flowing on the face of the slope, but none was observed at the proposed building
location.
Envirotech Engineering Geotechnical Report
PO Box 984 page 7 Parcel 32235-32-00041
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 April 14,2019
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 may be required in order to prevent the possibility of further
surficial or deep seated slope movements that may be damaging to life and property.
According to the Coastal Zone Atlas of Mason County, Washington, the project is within and
near terrain labeled `Stable' 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
Envirotech Engineering Geotechnical Report
PO Box 984 page 8 Parcel 32235-32-00041
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 April 14,2019
According to the Resource Map from the Washington State Department of Natural Resources
(DNR), the project is within terrain. labeled `highly unstable' relating to soils. DNR labeled
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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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 rad is 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 layer soil properties to 2 feet:
Soil unit weight: 132 pcf
Angle of internal friction: 30 degrees
Cohesion: 200 psf
Envirotech Engineering Geotechnical Report
PO Box 984 page 9 Parcel 32235-32-00041
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 April 14,2019
i
Soil Properties below 2 feet in depth:
Soil unit weight: 115 pcf
Angle of internal friction: 15 degrees
Cohesion: 750 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 over 1.5 and 1.1, 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 highly
Ma from the Washington State DNR, as provided above,
erodible. According to the Resource p gt
'highly erodible.' This Project is within an erosion hazard
the project is not within terrain labeled highly e o �
area as defined by the MCRO. Erosion hazard areas are those with USDA SCS 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 the 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
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.
4.3 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 Tacoma Fault Zone, in which is more than 4 miles to the northeast of this project.
This information is based on the USGS Quaternary Fault and Fold Database for the United States.
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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
Envirotech Engineering Geotechnical Report
PO Box 984 page 10 Parcel 32235-32-00041
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 April14,2019
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 indicated 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
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. A structural or geotechnical professional should design retaining walls based
on specific conditions. Soil parameters for the structural design of retaining walls may be
estimated as 134 pounds per cubic foot (pcf) and 138 pcf for engineered fill and native soils,
respectively. The angle of internal friction may be estimated as 36 degrees and 15 degrees for
engineered fill and native soils, respectively. These soil parameters are based on soil type and
placement conforming to the Earthwork Construction Recommendations Section in this report.
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 Geotechnical Report
PO Box 984 page 11 Parcel 32235-32-00041
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 April 14,2019
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 geotechnical investigation that is summarized in
the Subsurface Investigation Section; and, project research, analyses and conclusions as
determined inthe 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 tYPa of development.
ment.
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 shall be placed at a minimum of 18 inches below the native ground surface,
beneath existing fill and atop unyielding soils. For a columnar load of no more than 2.5 tons, a
circular or square isolated foundation diameter or width shall be at least 24 inches. Foundation
recommendations are made available based on adherence to the remaining recommendations that
are provided in this report. Alterations to the aforementioned foundation recommendations may
be completed upon a site inspection by a geotechnical engineer after the foundation excavation is
completed.
Envirotech Engineering Geotechnical Report
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Belfair,Washington 98528 Mason County,Washington
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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 6 inches of compacted coarse,
granular material (Retained on U.S. Sieve #10 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.
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.
Envirotech Engineering Geotechnical Report
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Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 April 14,2019
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
II U611STURBED 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. 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
3" 60— 100
No.4 20—60
No.200 0-8
Table 1
Particle 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.
5.2.3 Retaining Wall Backfill
Native soils should not be used as retaining wall backfill for this project for wall heights of at
least 4 feet. Native soils for retaining walls exceeding 4 feet in height must be approved by the
local authority or evaluated by an engineer using the lateral earth pressures provided earlier in
this report. Backfill may consist of engineered fill, as presented in this report, or borrow material
approved by a geotechnical engineer. Compaction of these materials shall be achieved in
compacted lifts of about 12 inches. Each lift should be uniformly compacted to at least 85%, and
no more than 90% of the modified Proctor maximum dry density (ASTM D 1557). If pavement
Envirotech Engineering Geotechnical Report
PO Box 984 page 14 Parcel 32235-32-00041
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 April 14,2019
or building loads are planned to be located within retaining wall backfill,then 90%compaction is
required. In addition, heavy construction equipment should be at a distance of at least ih the wall
height. Over-compaction and limiting heavy construction equipment should be prevented to
minimize the risk of excess lateral earth pressure on the retaining structure. Envirotech
recommends that retaining wall backfill is compacted with light equipment such as a hand-held
power tamper. If clean, coarse gravel soils are utilized as engineered fill, and surcharges will not
influence the retaining wall,compaction may be achieved by reasonably densifying granular soils
with construction equipment.
5.2.4 Wet Weather Considerations
Due to the types of subsurface soils,additional provisions may be required during prolonged wet
weather. We recommend earth cuts into the hillside be performed during the dry season of the
year(May 1"to October Ps . 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.
5.3 Building and Footing Setbacks
Building setbacks from the ascending slope are not required for this project if all
recommendations provided in this report are adhered to.
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
Envirotech Engineering Geotechnical Report
PO Box 984 page 15 Parcel 32235-32-00041
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 April 14,2019
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.
For this project, we recommend that infiltration is avoided in order to maintain slope stability,
and that roof downspout dispersion on splash blocks are employed. Recommended drainage
details are PP
provided in Appendix E of this report.
P
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, except
where needed for development. However, any other tree outside of the development footprint
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. In addition, 2 trees of the same species shall be planted for every hazardous tree
removed, and maintained until established. 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 Plan 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
Envirotech Engineering Geotechnical Report
PO Box 984 page 16 Parcel 32235-32-00041
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 April 14,2019
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 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 limited to an
engineered foundation wall if the proposed building is cut into the base of the hillside. The
engineer shall use the lateral earth pressures provided in this report, and the retaining wall backfill
recommendations in this report is considered as the active Rankine zone of influence on the wall.
In addition,the building should not extend into the hillside for more than 20 feet without further
geotechnical studies and subsequent recommendations.
Envirotech Engineering Geotechnical Report
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Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 April 14,2019
6.0 CLOSURE
Based on the project information provided by the owner, the proposed development, and site
P J
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
G� 't4y5
Jessica Legarza,M.S. Michael Staten,P.E.
Staff Geologist Geotechnical Engineer
Envirotech Engineering Geotechnical Report
PO Box 984 page 18 Parcel 32235-32-00041
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 April 14,2019
APPENDIX A
SITE PLAN
SOILS-MEDIUM DENSE SILTY SAND WITH GRAVEL(SM) I tQ l
OVERLYING SANDY CLAY WITH GRAVEL(SC) ��::/�
SCALE: 1 INCH = 100 FEET
25 50 ID
E STATE ROUTE 106
I
EXISTING SEPTIC DRAIWIELD
A
PROPOSED STRUCTURE
(APPRX)
7P
APPROXIMATE TOE IF
40----- CRITICAL SLOPE
EXCEEDING 40X-
a
0 FT VEGETATION REMOVAL
BUFFER FROM FACE OF CRITICAL BUILDING SHALL NOT
SLOPE EXCEPT AS PERMITTED IN ENCRMCH MORE THAN
GEOTECHNICAL REPORT 20FT INTO HILLSIDE
I
ENGINEERED
/ FOUNDATION WALLS
BUILDING SETBACKS NOT REQUIRED Y REQUIRED.SEE REPORT.
PER GEOTECHNICAL REPORT
PROPERTY LINE /
o
/ APPROXIMATE TOP OF
CRITICAL SLOPE
,o EXCEEDING 40%.
M
�P
� r
S
/
R
s x A,
$ fie
NOTES PROJECT/ OWNER/LOCATIOW
1.EROSION C13JTR13L 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. MANKE
CONTOURS WERE EXTRAPOLATED FROM A PUBLIC LIDAR SOURCE, AND PARCEL 32235-32-00041
INCORPORATED FIELD MEASUREMENTS AS EXPLAINED IN THE GEOTECHNICAL LEGEND MASON COUNTY,WASHINGTON
REPORT.
3. BOUNDARIES WERE NOT PREPARED BY A LICENSED SURVEYOR.LOCATIONS TEMPORARY ENGINEER-
OF SITE FEATURES THAT ARE SHOWN HERE, SUCH AS TOP [IF SLOPES, TOE +++EROSION CONTROL ENVIROTECH ENGINEERING
OF SLOOPES, WATER FEATURES,ETC.., WITH RELATION TO THE PROPERTY PO BOX 984
LINES MUST BE VERIFIED BY THE OWNER. RECOMMENDATIONS IN THE --"+� SLOE INDICATOR BELFAIR, WASHINGTOJ 98528
GEOTECHNICAL REPORT PROVIDE SETBACKS, BUFFERS, DEPTHS, ETC..WITH 360-275-9374
RELATION TO GEOLOGIC FEATURES, NOT PROPERTY LINES. THESE GEOLOGIC ..-Br- EXISTING CONTOUR
FEATURES MAY BE LOCATED ON THE SUBJECT PROPERTY OR NEIGHBORING PROPERTIES. ITPIe TEST PIT SITE PLAN
APPENDIX B
SOIL INFORMATION
VOTICAL AND HORIZONTAL SCML
SCALE. 1 DCH 60 FEET
0
12%t
<l
3
1$j�
EXISTING GRADE
MEDIUM DENSE SILTY SAND
WITH GRAVEL (SM)
q3!i
PROPO
HOUSE
a�
10%3
SANDY CLAY WITH GRAVEL (SC)
SECTION A-A
NOTES.
1)MINOR GRADE CHANGES REQUIRED IN ORDER TO ACHIEVE
POSITIVE DRAINAGE
2)THE SOIL PROFILE IS ACCURATE FOR THE DEPTH OF
THE OBSERVED TEST PITS AT THE SPECIFIED LOCATIONS,
LOWER DEPTHS ARE BASED ON SITE GEOLOGY,
WELL LOG(S),AND/OR EXPERIENCE IN THE GENERAL AREA,
TEST PIT LOG
TEST PIT NUMBER TP-1
PROJECT: Manke Geotechnical Report DATE OF LOG: 4/1/2019
PROJECT NO: 1904 LOGGED BY: MCS
CLIENT: Eric Manke
EXCAVATOR: N/A
LOCATION: E State Route 106 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 Medium brown,molst,medium dense
SILTY SAND with GRAVEL.Gravel is
primarily well-graded and subrounded.
1X Sand Is mostly medium.No plasticity.
2
t_ ? SC SANDY CLAY with GRAVEL. Sand is
medium and coarse grained.Low to
"! medium plasticity.
3
4
5 :..,
G
7
�•i
9
-� -�-�
10
Excavation terminated at approximately
10 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_Aldenvood gravelly sandy loam,30 to 50 percent slopes--Mason
County,Washington
Mason County, Washington
Ad—Alderwood gravelly sandy loam, 30 to 50 percent slopes
Map Unit Setting
National inap unit symbol: 2t628
Elevation: 50 to 800 feet
Mean annual precipitation: 25 to 60 inches
Mean annual air temperature: 46 to 52 degrees F
Frost-free period., 160 to 240 days
Farmland classification: Not prime farmland
Map Unit Composition
Alderwood and similar soils: 80 percent
Minor components: 20 percent
Estimates are based on observations. descriptions, and transects of
the mapunit.
Description of Alderwood
Setting
Landform: Ridges,hills
Landform position(two-dimensional): eackslope
Landform position(three-dimensional): Side slope,nose slope,taif
Down-slope shape: Linear,convex
Across-slope shape: Convex
Parent material: Glacial drift and/or glacial outwash over dense
glaciomarine deposits
Typical profile
A-0 to 7 inches: gravelly sandy loam
Bwl-7 to 21 inches: very gravelly sandy loam
Bw2-21 to 30 inches: very gravelly sandy loam
Bg-30 to 35 inches: very gravelly sandy loam
2Cd 1-35 to 43 inches: very gravelly sandy loam
2Cd2-43 to 59 inches: very gravelly sandy loam
Properties and qualities
Slope: 30 to 50 percent
Depth to restrictive feature: 20 to 39 inches to densic material
Natural drainage class: Moderately well drained
Capacity of the most limiting layer to transmit water(Ksat): Very
low to moderately low(0.00 to 0.06 in/hr)
Depth to water table: About 18 to 37 inches
Frequency of flooding: None
Frequency of ponding: None
Available water storage in profile: Very low(about 2.7 inches)
Interpretive groups
Land capability classification(irrigated): None specified
Land capability classification(nonirrigated): 7e
Hydrologic Soil Group: B
SDA Natural Resources Web Soil Survey 4Qr2019
Conservation Service National Cooperative Soil Survey Page 1 of 2
Mop Unit Description.Alderwood gravelly sandy loam,30 to 50 percent slopes---Mason
County,Washington
Hydric soil rating: No
Minor Components
Everett
Percent of map unit: 10 percent
Landform. Karnes,eskers,moraines
Landform position(two-dimensional): Backslope
Landform position(three-dimensional): Side slope
Down-slope shape: Convex
Across-slope shape: Convex
Hydric soil rating. No
Indianola
Percent of map unit: 5 percent
Landform: Eskers,kames,terraces
Landform position(three-dimensional): Tread
Down-slope shape: Linear
Across-slope shape: Linear
Hydric soil rating: No
Shalcar
Percent of map unit: 3 percent
Landform: Depressions
Landform position(three-dimensional): Dip
Down-slope shape: Concave
Across-slope shape: Concave
Hydric soil rating.: Yes
Norma
Percent of map unit. 2 percent
Landform: Depressions,drainageways
Landform position(three-dimensional): Dip
Down-slope shape: Concave,linear
Across-slope shape: Concave
Hydric soil rating: Yes
Data Source Information
Soil Survey Area: Mason County,Washington
Survey Area Data: Version 14,Sep 10.2018
15D.1 Natural Resources Web Soil Survey 4=019
+� Conservation Service National Cooperative Soil Survey Page 2 of 2
Map Unit Description:Everett very gravelly sandy loam,8 to 15 percent slopes--Alason
County,Washington
Mason County, Washington
Eh—Everett very gravelly sandy loam, 8 to 15 percent slopes
Map Unit Setting
National map unit symbol: 2t62b
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 rnapunit.
Description of Everett
Setting
Landform: Kames,eskers.moraines
Landform position(two-dimensional): Shoulder,footslope
Landform position(three-dimensional): Crest,base slope
Down-slope shape: Convex
Across-slope shape: Convex
Parent material: Sandy and gravelly glacial oufwash
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: 8 to 15 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 water storage in profile: Law(about 3.2 inches)
Interpretive groups
Land capability classification(irrigated): None specified
Land capability classification(nonirrigated). 4s
Hydrologic Soil Group: A
t.SD\ Natural Resources Web Sal Survey 4/2/2019
+0--0 Conservation Service National Cooperative Soil Survey Page 1 of 2
Map Unit Description Everett very gravelly sandy loam,8 to 15 percent slopes—Mason
County,Washington
Forage suitability group: Droughty Soils(G002XS401 WA),
Droughty Soils(G002XF403WA),Droughty Soils
(G002XN402WA)
Hydric soil rating: No
Minor Components
Alderwood
Percent of map unit: 10 percent
Landfonn: Ridges,hills
Landform position(two-dimensional): Shoulder
Landform position(three-dimensional): 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,kames,terraces
Landform position(three-dimensional): Riser
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 14,Sep 10,2018
1 SU.t Natural Resources Web Soil Survey V212019
+" Conservation Service National Cooperative Soil Survey Page 2 of 2
WATER WELL REPORT CI PMNT
Ort*w&Vow-Yodap,eaA-waer.rco J-drffi* Notice or tatent No.W 240290
ECOLOGY ConstruetiowDecommbsion("x".in clr ) Unique Ecology Well ID Tag No.BAR 1D4
® Construction .V Wow Rigbt Permit No.
❑ Decommission ORIGINAL INSTALLATION Property Owner Name MoKe Oblizalo
Notice o Intent Number
PROPOSED USE; ®Dometrie ❑ tedo" ❑ Mtmietpil well Strut Address 8830 E Stare Rtwhe t06-
❑DeWsoor ❑I ipfim.. ❑Test Wdl -"❑other City Union County Mason
TYPE OF WORK: Owods ember of well(if mere Theo one)_
IN New wdl ❑Rownghtwom Method:CIDug ❑Bored ❑Drives [cation nel/4 i/4 Stvl/4 Sec 3M. Twn 22n R 21y twat❑
❑Deepened M Cable ❑Rday ❑knod (s,t,r Still REQUIRED) Or
WWM II
DR1O?NSR]NS:Dise-w of wd16 iac3a,dakd72 R
Depth ofoognpletedwell72tL
CONSTRUCrIONDETAILS Lat/iong Lat Deg LatMiMScc
C,;a M Weldod 6 Doom sour+1 a to 67 tL Long Deg_ Long Min/Sec _
lrtalled: ❑Lb a inmlied Diam.son_ft a ti Talc Parcel No.(Requi 3223532DDo70
❑1Ueaded _" Dim.Form It to —I
P.faatiam: Yea ®No CON311tUCr10N OR DECOMMISSION PROCEDURE
Type of p.for>mr end Farmsaioe:Daerbs by tutor,o6aracYa,sae of msmil ad staact m and the►md and
SITE of perfs_im by_in.and no.of pa6_flan R to_-A _oatme of the material u each atratom pmMatrd,with at knot one entry fen eacb<bange
ofidormation.(USE ADDCIIONAL SHEETS IF NECESSARY.)
Srnss: ® Yes [I No ®K-Pac I.oatioa 65
MATERIAL FROM TO
Manefach—'s Name Johnson Br sand&gravel 0 14
Type slainlass steal Model No. Br till 14 19
Du-DSlat sine 12 kom 67 R;72 R 19 40
Diam. SkA sue fiom ft.to 2 D day`Mr gavel soft
Dark tx gavel 3 water 48 53
G,a&vRtrr putted:❑Yes M No Sin of V a Ifs td Tan fine sand water bearing 53 72
Materials placed from_—a.to_R
Surface Seat:®Yes ❑No To*bat depth?19.5E
Mataiat used is seal bentonite
Did coy strap oDdaw umtnbk wagdt ❑Ya N No .
Type of wagd7 . . Depth of strata
Method of sestiot aorta off' ..
PUMP.ManaScima'aNune90Uld$
Type:sublrtRmtge 11P. 1
WATER LEVELS:ladaefioe ekvatim above tea on kvei_fL �� t N.,O
Shoe k-M R&below top of mH Date 3-5-10 O a, 0 '
Artesian prawre_net.pa a*=tom Dame
Artesia*ages is oe a,oGM by (cop,vwK,cte.) We ® '" f�n .
WELL TTSTS:Drawdowa u amoea*user krd u toward below static level
Was a pmep eel made?❑Yes M No If yq by whom?
Yreld:_.al/rein.with_R dnwdown all._her.
Yield:�1/min.w06,R dnwdown a(ta_hrn 01 Ga'
Yeld:_•pl/min with_R drawdawc all._lath _
Rem.sry aHa(live taken as—when peep tanned tg 6-ter k d aseastordfioas
Wd/top to water lewd)
Time Water t.esel Time Water L—I Time Water Le-I j
Date of lest
B.I.test ZQ galJmia.with iQa.drawdowa afla 4trs.
Ainest 011mm wah stem W at R fQ_her.
ndes;an now cp.m.Dagc 3s10 Start DtIDe 3-0 - Completed!Date 3 5-10
Temp.uere of water was a cbemieal aealyti made? ❑Yes ®No
WELL CONSTRUCTION CFXMCATION:I comWged and/or nsxa:pt responsibility for oom-truaion ofthis well,and its con ylieoce with all Washington well I'
otacatruction standards, Mataials used mod the information reported above me true to my best loaosrkd6e and bdieC
I rillingCompany KNAPP DRILLING _
Drills T. N tj t.E S Address 50 EAST LESACA DR_
Dfiller/Engineatrrmnee Signag. City,State,Zip SHELTON WA.98594
Driller Of frrtirKC Lilxitse No.2921T __
IF TRAINEE:Drilla's Liana No:1706 Contractor's
Drdtei s Signature: Registrmrion No KNAPPDt NW Dale 3-9-10
ECY 050-1-20(Rev OLIO) if,.neeC:.od this docunrnr in an alternate forma{please call the Water Resources Program at 360-I07-"77.
Persons with hearing loss can mil 711 jor Washington Relay Servicr. Persons with a speech disabitity can calf 8 -M� 341.
APPENDIX C
SLOPE STABILITY
IL _ O 0
i _ i0
1 _ 2 0
_ 30
_ 4 0
_ 5 O
2
1 _ 7 0
1 90
1 90
t�
,r
ft
-40
Pj
Datafil� = Dyizamic Analysis
Analysis = Bishop
wTr.wt.c.-�nn� wa A.wwa�.lwrww t.��y
c O VE IV-C IR = S'TS1STht'Li�
T T-w xx%r -C 'we a.s T T 9 IE,C VI
C a. C-=1 T-T'k--r4 -- C 4D=a
0 fs
09 T,
C) L. T
09 T
os -
0 tp
0 e
0 = - T
0 T -r
0 0 T
r
APPENDIX D
EROSION CONTROL
GEOTEXTILE FABRIC
WRAP AROUND TRENCH
TO AT LEAST ENTIRE
BOTTOM OF TRENCH
BEFORE PLACING GRAVEL LE
' ' 5' WOOD POST OR
12' DEEP, 8' WIDE TRENCH LENT OR BETTER
FILLED WITH 3/4' TO 1 1/2'
WASHED GRAVEL ❑R VEGETAT�N
DIRECTION OF ----- STING
WATER FLOW UND SURFACE
�z•
T 2.5 FT
SILT FENCE - CROSS SECTION
N.T.S.
2'x2' WOOD POST (TYP) GEOTEXTILE FABRIC
OR EQUIVALENT OR BETTER AND WIRE MESH
@ 6 FT MAX. O.C.
F-- 6 FT I r U.5 FT
EXISTING t
GROUND SURFACE
z
12' DEEP, 8' WIDE 1F7
TRENCH FILLED WITH
3/4' TO 1 1/2' 1 2.5 FT
WASHED GRAVEL OR VEGE TI
BOTTOM EXTENTS OF citT FENCE - DETAIL
GEOTEXTILE FABRIC
N.T.S.
PROVIDE FULL WIDTH
3/4 IN TO 1 I/2_ N20 INGRESS/EGRESS
FT
CRUSHED GRAVEL
PLACED AT 6 IN
MINIMUM DEPTH
WELL-DRAINED
SOILS
-0.02 IN/MIN FULL "
R=25 FT MIN
ACCESS RMD
STABILIZED CONSTRUCTION ENTRANCE
N,T.S.
PERMANENT ERASION CONTROL NOTES-
ENERAL NOTES-
SEEDING FOR RAW SI.pPES
SHOULD THE TEMPORARY EROSION AND SEDIMENT CONTROL MEASURES SHOWN ON
FESE PLANS PROVE TO BE INADEQUATE DURING CONSTRUCTION,THE CONTRACTOR L BEFORE SEEDING,INSTALL NEEDED SURFACE RUNOFF CONTROL
HALL INSTALL ADDITIONAL EROSION AND SEDIMENT CONTROL FACILITIES, MEASURES SUCH AS GRADIENT TERRACES,INTERCEPTOR DIKES,
ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE SVALES,LEVEL SPREADERS AND SEDIMENT BASINS,
NSPECTED DAILY AND IMMEDIATELY MAINTAINED,IF NECESSARY. 2.THE SEED BED SHALL BE FIRM WITH FAIRLY FINE SURFACE,
ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE LEFT IN FOLLOWING SURFACE ROUGHENING.PERFORM ALL OPERATIONS ACCROS
LACE UNTIL THE UPSLOPE AREAS HAVE BEEN PERMANENTLY STABILIZED, OR PERPENDICULAR TO THE SLOPE,
3. SEEDING RECOMMENDATIONS, AS SHOWN BELOW, AND SHOULD BE
MPORARY EROSION CUNTR13L NOTES- APPLIED AT THE RATE OF 120 POUNDS PER ACRE,
4. SEED BEDS PLANTED BETWEEN MAY 1 AND OCTOBER 31 WILL
OR ALL AREAS WHICH HAVE BEEN STRIPPED 13F VEGETATION OR EXPERIENCED LAND REQUIRE IRRIGATION AND OTHER MAINTENANCE AS NECESSARY TO
ISTURBING ACTIVITIES, AND WHERE NO FURTHER WORK IS ANTICIPATED FOR A FOSTER AND PROTECT THE RODT STRUCTURE,
RIOD EXCEEDING THE LISTED CRITERIA BELOW, ALL DISTURBED AREAS MUST BE 5. SEED BEDS PLANTED BETWEEN NOVEMBER 1 AND APRIL 30,
MMEDIATELY STABILIZED WITH MULCHING, GRASS PLANTING OR OTHER APPROVED ARMORING OF THE SEED BED WILL BE NECESSARY,(e.g.,
ROSION CONTROL TREATMENT APPLICABLE TO THE TIME ff' YEAR. GRASS SEEDING GEOTEXTILES, JUTE MAT, CLEAR PLASTIC COVERING).
ONE WILL ONLY BE ACCEPTABLE DURING THE MONTHS OF APRIL THROUGH 6.FERTILIZERS ARE TO BE USED ACCORDING TO SUPPLIERS'
EPTEMBER.HOWEVER, SEEDING MAY PROCEED WHENEVER IT IS IN THE INTEREST OF RECOMMENDATIONS.AMOUNTS SHOULD BE MINIMIZED,ESPECIALLY
HE OWNER/CONTRACTOR, BUT MUST ALSO BE AUGMENTED WITH MULCHING, NETTING ADJACENT TO WATER BODIES AND WETLANDS.
R OTHER APPROVED TREATMENT,
USE THE FOLLOWING RECOMMENDED SEED MIXTURE F13R EROSION
RY SEASON (MAY 1 THfRU SEPTEMBER 30)--THE CLEARING OF LAND,INCLUDING THE CONTROL, OR A COUNTY APPROVED ALTERNATE SEED MIXTURE
EMOVAL OF EXISTING VEGETATION OR OTHER GROUND COVER,MUST BE LIMITED TT1
NLY AS MUCH LAND AS CAN RECEIVE APPROPRIATE PROTECTIVE COVER OR BE PROPORTIONS PURITY GERMINATION
THERVISE STABILIZED,AFTER HAVING BEEN CLEARED OR OTHERWISE DISTURBED , NAME BY WEIGHT(%) (X) <%)
Y NO LATER THAN SEPTEMBER 30 OF A GIVEN YEAR. UNLESS IMMEDIATE
TABILIZATION IS SPECIFIED IN THE EROSION AND SEDIMENT CONTROL PLAN, ALL REDTOP (AGROSTIS ALBA) 10 92 90
REAS CLEARED OR OTHERWISE DISTURBED MUST BE APPROPRIATELY STABILIZED ANNUAL RYE(LOLIUM MULTIFLI3RUM) 40 98 90
ROUGH THE USE OF MULCHING, NETTING, PLASTIC SHEETING,EROSION BLANKETS, CHEWING FESUE 40 97 80
REE DRAINING MATERIAL,ETC., BY SEPTEMBER 30 OR SOONER PER THE APPROVED (FESTUCA RUBRA COMMUTATA)
LAN OF ACTION. UNLESS OTHERWISE APPROVED BY THE COUNTY,SEEDING, (JAMESTOWN, BANNER, SHADOW, KOXET)
ERTILIZING AND MULCHING OF CLEARED OR OTHERWISE DISTURBED AREAS SHALL BE WHITE DUTCH CLOVER 10 96 90
RFORMED DURING THE FOLLOWING PERIODSN MARCH 1 TO MAY 15, AND AUGUST 15 TO (TRIFOLIUM REPENS)
CTOBER L SEEDING AFTER OCTOBER 1 WILL BE DONE WHEN PHYSICAL COMPLETION
THE PROJECT IS IMMINENT AND THE ENVIROMENTAL CONDITIONS ARE CONDUCIVE MULCHING
13 SATISFACTORY GROWTH IN THE EVENT THAT PERANENT STABILIZATION 1S NOT
OSSIBLE,AN ALTERNATIVE METHOD OF GROUND COVER, SUCH AS MULCHING,NETTING,L MATERIALS USED FOR MULCHING ARE RECOMMENDED TO BE WOOD
LASTIC SHEETING, EROSION BLANKETS, ETC., MUST BE INSTALLED BY NO LATER THAN FIBER CELLULOSE, AND SHOULD BE APPLIED AT A RATE OF 1000
EPTEMBER 30. POUNDS PER ACRE.
2.MUCH SHOULD BE APPLIED IN ALL AREAS WITH EXPOSED SLOPES
N THE EVENT THAT CONSTRUCTION ACTIVITIES DR OTHER SITE DEVELOPMENT GREATER THAN 24 QpRIZONTALMVERTICAU,
CTIVITIES ARE DISCONTINUED FOR AT LEAST 4 CONSECUTIVE DAYS, THE 3.MULCHING SHOULD BE USED IMMEDIATELY AFTER SEEDING OR IN
WNER/CONTRACTOR SHALL BE RESPONSIBLE FOR THE INSPECTION OF ALL EROSION AREAS WHICH CANNOT BE SEEDED BECAUSE[IF THE SEASON,ALL
ND SEDIMENT CONTROL FACILITIES IMMEDIATELY AFTER STORM EVENTS, AND AT AREAS REQUIRING MUCH SHAD. BE COVERED BY NOVEMBER 1.
AST ONCE EVERY WEEK. THE OWNER/ CONTRACTOR SHALL BE RESPONSIBLE FOR
HE MAINTENANCE AND REPAIR IF ALL EROSION AN SEDIMENT CONTROL FACILITIES. TOPSORING
ET SEASON (OCTOBER 1 THRU APRIL 30)—ON SITES WHERE UNIINTERUPTED L TOPSOIL SHOULD BE USED FOR THIS PROJECT DUE TO HIGHLY
ONSTRUCTION ACTIVITY IS IN PROGRESS,THE CLEARING OF LAND,INCLUDING THE DENSE EXPOSED SOILS.
EMOVAL OF EXISTING VEGETATION AND OTHER GROUND COVER, SHALL BE LIMITED 2,TOPSOIL SHOULD BE PLACED ON SLIDES NOT EXCEEDING 211.
0 AS MUCH LAND AREA AS CAN BE COVERED OR STABILIZED WITHIN 24 HOURS IN 3.STRIPPING AND STOCKPILING ON-SITE SOTS SHALL ONLY BE
HE EVENT A MAJOR STORM IS PREDICTED AND/ OR EROSION AND SEDIMENT PERMITTED IF TOPSOIL IS FRIABLE AND L3AMY (LOAM, SANDY LOAN,
RANSPORT CFF-SITE IS OBSERVED, SILT LEAN, SANDY CLAY LOAM,CLAY LOAM),
LL CLEARED OR DISTURBED AREAS SHALL RECEIVE APPROPRIATE PROTECTIVE 4, STRIPPING SHALL BE CONFINED THE IMMEDIATE ON RUCTION
AREAS'A FOUR TO SIX INCH STRIPPPI
OVER OR BE OTHERWISE STABILIZED, SUCH AS MULCHING, NETTING, PLASTIC THE
DEPTH IS COMMMON,, UT BBUT
MEETING,EROSION BLANKETS, FREE DRAINING MATERIAL,ETC., WITHIN 5 DAYS AFTER SURFACE RUNOFF CONTROL STRUCTURES SWILL HE IN PLACE BEFORE
SUR MAY VARY DEPENDING ON THE PARTICULAR SOIL ALL
WING BEEN CLEARED OR OTHERWISE DISTURBED IF NOT BEING ACTIVELY WORKED.
STRIPPING.
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
NG ACTIVELY WORKED REMAINS UNPROTECTED OR HAS NOT BEEN APPROPRIATELY
TABILIZED 5 DAYS AFTER HAVING BEEN CLEARED,ALL CONSTRUCTION ACTIVITY ON
SITE,EXCEPT FOR APPROVED EROSION AND SEDIMENT CONTROL ACTIVITY, SHALL
MM(EDIATELY CEASE UNTIL SUCH A TIME AS AFOREMENTIONED LAND AREA HAS BEEN
PPRGPRIATELY PROTECTED DR STABILIZED.
STUCKPD.E MANAGEMENT
L STOCKPILE SMALL BE STABILIZED(VITM PLASTIC COVERING OR OTHER APPROVED DEVICE)DAILY K7VECN NEIVEMIER 1 AND MARCH
3L
2.IN ANY SEASON,SEDIMENT LEACHING FROM STOCK PIES MUST BE PREV04TEL
3.TOPSOIL SHALL NUT BE PLACED WHILE W A FROZEN OR MUDDY CINDITIN,WHEN THE SUBGRADE IS EXCESSIVELY WET,DR WHEN
CONDITIONS EXIST THAT MAY OTHERWISE BE DETRIMENTAL TO PROPER GRADING OR PROPOSED SODDING OR SEEDING.
4.PREVIOUSLY ESTABLISHED GRADES ON THE AREAS TO BE TOPSOILED SHALL BE MAINTAINED ACCORDING TO THE APPROVED PLANS.
STABILIZED CONSTRUCTION ENTRANCE
L MATERIAL SHALL BE 4 INCH TO 8 INCH QUARRY SPALLS (4 TO 6 INCH FOR RESIDENTIAL SINGLE FAMILY LOTS)AND MAY BE
TEP-DRESSED WITH 1 INCH TO 3 INCH ROCK. (STATE STANDARD SPECIFICATIONS,SECTION 8-15.)
2.THE ROCK PAD SHALL BE AT LEAST 12 INCHES THICK AND 50 FEET LONG(20 FEET FOR SITES WITH LESS THAN 1 ACRE
DISTURBED SOIL).WIDTH SHALL BE FULL WIDTH OF THE VEHICLE INGRESS AND EGRESS AREA,SMALLER PADS MAY BE APPROVED
FOR SINGLE-FAMILY RESIDENTIAL AND SMALL COMMERCIAL SITES.
3.ADDITIONAL ROCK SHALL BE ADDED PERIODICALLY TO MAINTAIN PROPER FUNCTION IF THE PAD.
4.IF THE PAD DOES NOT ADEQUATELY REMOVE THE MUD FROM THE VEHICLE WHEELS,THE WHEELS SHALL BE HOSED OFF BEFORE
THE VEHICLE ENTERS A PAVED STREET. THE WASHING SHALL BE DONE ON AN AREA COVERED WITH CRUSHED ROCK AND WASH
WATER SHALL DRAIN TO A SEDIMENT RETENTION FACILITY OR THROUGH A SILT FENCE
ILT FENCE
GEOTEXTILE FILTER FABRIC TYPE SHALL BE PER SPECIFIED IN THE'STORMWATER MANAGEMENT MANUAL
OR THE PUGET SOUND BASIN,' OR APPLICABLE COUNTY STANDARDS
GEOTEXTILE FILTER FABRIC SHALL BE PURCHASED IN A CONTINUOUS ROLL CUT TO THE LENGTH OF
ACH BARRIER TO AVOID USE OF JOINTS.IF .HINTS ARE NECESSARY,FILTER FABRIC SHALL BE SPLICED
OGETHER ONLY AT A SUPPORT POST WITH A MINIMUM 6-INCH OVERLAP AND SECURELY FASTENED AT
OTH ENDS TO THE POST.
STANDARD FILTER FABRIC SHALL BE FASTENED USING 1' STAPLES OR TIE WIRES<FOG RINGS) 8 4 IN
PACING,
POSTS SHALL BE SPACED AND PLACED AT DEPTHS INDICATED IN THE DETAILS IN THIS SHEET,AND
RIVEN SECURELY INTO THE GROUND.
WIRE MESH SHALL BE 2'X2'X14 GAUGE OR EQUIVILEMT,THE WERE MESH MAY BE ELIMINATED IF
TRA-STRENGTH FILTER FABRIC (MONOFILAMENT), AND CLOSER POST SPACING IS USEII
A TRENCH SHALL BE EXCAVATED ACCORDING TO THE DETAILS ON THIS SHEET ALONG THE LINE tF THE
OSTS AND UPSLEPE FROM THE SILT FENCE.
SILT FENCES SHALL BE LOCATED D13WNSLOPE FROM THE CLEARING LU41TS 13F THE PROJECT.
APPENDIX D
DRAINAGE DETAILS
HOUSE
ROOF DOWNSPOUT
SERVES UP TO
700 SF OF ROOF
50 FT MIN
VEGETATED
FLOW PATH
D❑WNSP❑UT
EXTENSION
ROOF DOWNSP❑UT AND SPLASH BLOCK DETAILS
N.T.S.
GEO 21061- �
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: Wl6Ln kQ
Permit#: 1� ��U<,31 Parcel#: �ZZ�S' 3 2- ('��L)`4
Date(s)of the Document(s) reviewed:
1. (a) A discussion of general geologic conditions in the vicinity of the proposed development,
OK? Comment:
(b) A discussion 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
incorporates 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 coeffients should be a value of 0.15.
OK? — Comment:
7. (a) Appropriate restrictions on placement of drainage features
OK? Comment:
(b) Appropriate restrictions on placement of septic drain fields
OK? Comment:
(c) Appropriate r on placement of compacted fills and footings.
OK? Comment:
Page 1 of 2 Form Effective June 2008
I
(d) Recommended 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 construction methods.
OK? Comment:
10. An analysis 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 widths.
OK? — Comment:
12. Recommendations 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 and proposed development on the site.
OK? J Comment:
Are the Documents signed and stamped? By whom?_M.4r�
License#: UTA S License type:
FIRST REVIEW �4pproved ❑ Need more info.
If not approved, what is the next action/recommendation for further action?
Reviewed by V2— —, on 7 / Time spent in review:
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