HomeMy WebLinkAboutGEO2016-00035 - GEO Geological Review - 3/11/2016 Ile - �3�
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` Geotechnical Report
for
Callin Single Family Residence
North Shore Road
Parcel No. 32207-50-009n 23
Mason County, Washington
March 11, 2016
Project#1617
Prepared For:
Grant Catlin
21631 NE 24`h St ` oFCwn T9�
Sammamish, Washington 98074 I
Prepared By:
Envirotech Engineering °�,- GI s ��°
PO Box 984 SSIONALE�'�'
Belfair, Washington 98528
Phone: 360-275-9374
GEO 2L t
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: CaK. t h
Permit#: '�j Z.�-mac, or_31� Parcel#: 7-2�' 1
Date(s) of the Document(s) reviewed: Ce I 1 r, (�1
1. (a) A discussio f general geologic conditions in the vicinity of the proposed development,
OK? Comment:
(b) A discussion of specific soil types
OK? ✓ Comment:
(c) A discussi9 of ground water conditions
OK? '✓ Comment: 1
(d) A discussio of the upslope geomorphology
OK? 1/ Comment: 5
(e) A discussioy�-of the location of upland waterbodies and wetlands
OK? ✓ Comment:
(f) A discussio of history of landslide activity in the vicinity, as available in the referenced maps and records
OK? Comment:>5
2. A site p7Comment:
that identifies the important development and geologic features.
C . c,, iP P
3. Locations nd logs of exploratory holes or probes.
U. ✓ 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? y Comment: (�i �-c
5. A minimum of one cross section at a scale which adequately depicts the subsurface profile, and which
incorporat the details of proposed grade changes.
OK? Comment: + 1
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 co$ffients should be a value of 0.15.
OK? V/ Comment: L
7. (a) Appropriate strictions on placement of drainage features
OK? Comment: 1 F
(b) Appropriate r strictions on placement of septic drain fields
OK? Comment: I w
(c) Appropriate,Festrictions on placement of compacted fills and footings.
OK? �/ Comment: I I U
Page 1 of 2 Form Effective June 2008
(d) Recommend d buffers from the land ide h zard areas shoreline bluffs and the tops of other slopes.
OK? Comment: (g ' -z5 -k-6 4�_ VA , V 4L V V e-, -C.-
rr—
(e) Recommerfded setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes.
OK? Comment: I -, 2S
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: I no
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? v 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 7C' omment-.
OK?
12. Recommendations for the preparation of structural mitigation or details of other proposed mitigation.
OK? Comment: l"I
13. A site map drawn to scale showing the property boundaries, scale, north arrow, and the location and nature of
existing an proposed development on the site.
OK? Comment:
Are the Documents signed and stamped? By whom? �C ' Lt
License#:4 3 U Ll S License type: {P!✓
FIRST REVIEW ❑ Approved ❑ Need more info.
If not approved, what is the next action/recommendation for further action?
Reviewed by on . 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
a
Mason County Department of Community Development
Submittal Checklist For a Geotechnical Report
Instructions:
This checklist must be submitted with a Geotechnical Report and completed, signed, and stamped by the
licensed professional(s) who prepared the Geotechnical Report for review by Mason County pursuant to
the Mason County Resource Ordinance. If an item found to be not applicable, the report should explain
the basis for the conclusion.
Applicant/Owner 611-�ri� ��i/h Parcel# 32- '"—fir'
Site Address XXX A//1/"M 7 c,A YL=
(1) (a)A discussion of general geologic conditions in the vicinity of the proposed development,
Located on page(s) ,3--
(b) A discussion of specific soil types
Located on page(s) h
(c) A discussion of ground water conditions
Located on page(s) 7
(d) A discussion of the upslope geomorphology
Located on page(s) S
(e) A discussion of the location of upland waterbodies and wetlands
Located on page(s) s
(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) 91*'
(2) A site plan which identifies the important development and geologic features.
Located on Map(s) 15,
(3) Locations and logs of exploratory.holes or pro es.
Located on Map(s) �� G-�: I /�/41
(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) l6i7
(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)
(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) /0
(7) (a)Appropriate restrictions on placement of drainage features
Located on page(s) /Ci
(b) Appropriate restrictions on placement of septic drain fields
Located on page(s) /
(c) Appropriate restrictions on placement of compacted fills and footings
Located on page(s)�¢, /L
Page 1 of 2 Form Effective June 2008
Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report.
A
(d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other
slopes on the property.
Located on page(s) f1f
(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) �6
(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) /(
(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) i 7 —l f
(12) Recommendations for the preparation of structural mitigation or details of other proposed
mitigation.
Located on page(s) I�'
(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.
��Loc�ated on Map((ss) e",_Ae' alms
1, /"t iduly � G ✓"11 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.JI also certify that the Geotechnical
Report, dated /r /� ?-Viand entitled cex//1)7
liilc�/ /�;44+ 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)
6�C YDF
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Page 2 of 2 Form Effective June 2008
Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report.
A `
Table of Contents
1.0 8
8.8 PROJECT INFORMATION........................................................................................................................................l
1'2 PURPOSE mFINVESTIGATION AND SCOPE mF WORK.............................................................................................l
2.00U8FACE CONDITIONS......................................................................................................................................3
2.8KENEmwALOmSEmmmznONS.....................................................................................................................................3
2.2ToPoGmApmv........................................................................................................................................................3
2.21UpnlomeGeomorphw8off.............................................................................................................................3
2.30mamACE DRAINAGE.............................................................................................................................................3
23.1 UpnlopeWamer Boi&ev..................................................................................................................................3
2.4 SLOPE AND EROSION OBSERVATIONS...................................................................................................................4
� 3.000BSUKFACE 5
�
3.1 FIELD METHODS,SAMPLING AND FIELD TESTING...............................................................................................5
� 3.2 GENERAL GEOLOGIC CONDITIONS.......................................................................................................................5
330nECIFIC SnmmwRmA«E CONDITIONS.--.-.--.-._-_.------._--_---'-----.-----.-_'---'6
� 3.3.1 Groundwater................................................................................................................................................7
4.0 ENGINEERING ANALYSES AND .______-8
� 4.1 SLOPE STABILITY..................................................................................................................................................Q
� 4.L1 SlopeSuWbi0o Analysis.............................................................................................................................}0
4.2 DRmmm«N..-----.---__-__-_--.----_--_----'__---_-_--_-_-_-.---_-_---'--_—..l]
430EImMIc CONSIDERATIONS AND LiQnmmA«Tmww.................................................................................................l2
4.3.1 Liqudkedon...............................................................................................................................................}J
4.4 LANDSLIDE,EROSION AND SEISMIC H«zxRDs CONCLUSIONS------.------------------.l%
� 4.5D^ATEmAL EARTH PRESSURES.-----------.-------------------.-----------l8
4.6 ON-SITE AND OFF-SITE IMPACTS.......................................................................................................................l3
5.0 14
� 5.1 BUILDING FOUNDATION RECOMMENDATIONS-...---_--____'--_.-_-_-_-_.-_-'-_-_.---_-_l4
5.&I Bearing Capacity.......................................................................................................................................{4
� S.L2 Settlement..................................................................................................................................................Jj
� 5.1.3 Concrete S8abs-on-&rmde........................................................................................................................../5
5.2 EARTnwoxK CwmorRn«nION RECOMMENDATIONS-----_---_.---'---'--_-''--_-'----_-l5
� 5.21 Excavation.................................................................................................................................................l5
� 5.Z2 Placement and Compaction ofNative Solis and 8nginenxodFW............................................................}6
5.23@&taiming Wall Xau0fill............................................................................................................................./7
5.2.4 Wet Weather Considerations.....................................................................................................................J7
5.2.50ufldng Pmik............................................................................................................................................/7
5.3 BUILDING AND FOOTING SETBACKS...................................................................................................................l7
5.4 SURFACE AND SUBSURFACE DRAINAGE..............................................................................................................1m
5.5 VEGETATION BUFFER AND .------.---.-'--._--.----._-.-----.---'l8
5.6 TEMPORARY AND PERMANENT EROSION CONTROL...........................................................................................l9
s.rSmffic0mm^om«ELDS..........................................................................................................................................l9
5.88nRm«TmRAL MrnzGATxoN.................................................................................................................................l9
6.0 CLOSURE___ _-_---------.---_--_--_-----_----.-- 20
Appendix A-Site Plan
� AypendiuB-Smi Information �
�
� Appendix C-Slope Stability
� Appendix D-Erosion Control
�
1.0 INTRODUCTION
Envirotech Engineeringnvirotech has completed a geotechnical investigation fora lanned
(Envirotech) P gP
single family residence located at XXX NE North Shore Road, identified as parcel number
32207-50-00951, Belfair, Mason County, Washington. See the vicinity map on the following
page for a general depiction of the site location.
The geotechnical investigation was conducted at the request of the proponent of the property,
Grant Callin, in support of the proposed development as detailed below. The proposed
development,as provided herein,and the surrounding area that may influence the development, is
identified throughout this report as the Project.
An initial geotechnical evaluation of the Project was conducted by Envirotech on July 13, 2015,
and October 26, 2015. 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, 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 during the geotechnical investigation. Other Project information was obtained by
Envirotech.The site is currently undeveloped land. The planned development consists of a 1-or
2-story single family residence, new on-site septic system, gravel driveway, 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:
Envirotech Engineering XXX NE North Shore Road
PO Box 984 page I Parcel 32207-50-00951
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 March 11,2016
t i
• 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
references concerning slope stability, and review water well reports from existing wells
near the Project;
• Collect bulk samples at various depths and locations;
• Perform soils testing to determine selected index and/or engineering properties of the site
soils;
• Complete an engineering analysis supported by the planned site alterations, and the
surface and subsurface conditions that were identified by the field investigation, soil
testing,and applicable project research;and,
• Establish conclusions based on findings, and make recommendations for foundations,
drainage, slope stability, erosion control, earthwork construction requirements, and other
considerations.
r
Project
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Vicinity Map from Mason County Website
Envirotech Engineering XXX NE North Shore Road
PO Box 984 page 2 Parcel 32207-50-00951
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 March 11,2016
2.0 SURFACE CONDITIONS
Information pertaining to the existing surface conditions for the Project was gathered on July 13,
2015, and October 26,2015 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
The property is accessed from North Shore Road, an existing roadway in Tahuya, Washington.
The Project is currently undeveloped land as previously mentioned.The access road extends near
the east property line, and Hood Canal borders the property to the west. Beyond the property,
rural residential development exists.Vegetation on and near the Project consists primarily of firs,
cedars, madronas, 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.
Descending slopes are relatively minor to the west of the planned development. Grades are
approximately10%from the planned development to the shoreline.
Critical Ascending grades are generally located to the east of the planned development. These
slopes are relatively steep within 300 feet of the Project, with grades exceeding 40%,
approximately 26 feet to the east of the planned development. The maximum critical slope is
approximately 50%with a vertical relief of approximately 60 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
Runoff originating upslope of the development is mostly diverted away from the property by
accommodating topography. 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
Envirotech Engineering XXX NE North Shore Road
PO Box 984 page 3 Parcel 32207-50-00951
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 March 11,2016
development that would significantly influence the Project.
2.4 Slope and Erosion Observations
The slope grades near the Project signal a potential landslide or erosion hazard area. Some
indicators that may suggest past slope movements include:
• Outwash of sediments near the bottom of the slope,
• Fissures,tension cracks, hummocky ground or stepped land masses on the face or top of
the slope,and parallel to the slope,
• Fine,saturated subsurface soils,
• Old landslide debris,
• Significant bowing or leaning trees,or,
• Slope sloughing or calving.
Many of the above mentioned slope instability indicators are present within the vicinity of the
property.Indications of deep-seated slope problems were not observed during the site visit.
.. ►ter- !" - '^ � i _C ry y''. •�,. i�
Aerial Photo from Google Website
Envirotech Engineering XXX NE North Shore Road
PO Box 984 page 4 Parcel 32207-50-00951
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 March 11,2016
3.0 SUBSURFACE INVESTIGATION
Information on subsurface conditions pertaining to the Project was primarily gathered on July 13,
2015, and October 26, 2015 by a representative with Envirotech. Specific information on field
methods, sampling, field testing, general geologic conditions, specific subsurface conditions,and
results from soil testing are presented in this section of the report. Appendix 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 extending to depths of up to 5 feet below the existing ground surface, and observing cut
slopes/ shoreline banks of up to 12 feet within the vicinity of the property. 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 5 feet 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 Lilliwaup Valley and Union 7.5-minute Quadrangles, Mason County,
Washington" by Trevor A. Contreras, Gabriel Legorreta Paulin, Jessica 1. Czajkowski, Michael
Polenz, Robert L. Logan, Robert J. Carson, Shannon A. Mahan, Timothy J. Walsh, Chris N.
Johnson,and Rian H. Skov, June 2010,provides the following caption(s)for the project area:
Pre-Fraser Olympic-source outwash—Gravel(Clark Creek Drift?)with paleosols:orange-
brown:dense:clasts subrounded:poorly stratified to massive:poorly to moderately sorted.
Envirotech Engineering XXX NE North Shore Road
PO Box 984 page 5 Parcel 32207-50-00951
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 March 11,2016
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Geological Map Department of Natural Resources Washington State
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 without indications of borrowed fill. Within test
pit locations, soils within the upper 5 feet of natural ground were observed to be moist, reddish
brown silty sand with gravel (SM). Soils below the upper 5 feet and starting at a depth of
approximately 8 feet below the ground surface are expected to be mostly grey, low moisture, silty
sand with gravel(SM).
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 Rough Broken Land, Rb.
The soil designations are depicted in the aerial photograph below, and descriptions are provided
in Appendix B of this report.
Envirotech Engineering XXX NE North Shore Road
PO Box 984 page 6 Parcel 32207-50-00951
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 March 11,2016
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Soil Survey From USDA Natural Resources Conservation Service
33.1 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. Surface seepage
or perched groundwater at shallow depths was not observed on-site, nor indicated on the
well reports.
Envirotech Engineering XXX NE North Shore Road
PO Box 984 page 7 Parcel 32207-50-00951
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 March 11,2016
4.0 ENGINEERING ANALYSES AND CONCLUSIONS
The followingsections present engineering analyses and conclusions with relation to the existing
conditions and proposed improvements of the Project. This section includes slope stability,
erosion, seismic considerations, lateral earth pressures, 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 defming engineering properties of the soil, topography, water
conditions,seismic acceleration and surcharges.
Surface sloughing or other types of surficial slope movements usually do not affect the deep-
seated structural capability of the slope. However, excessive and/or repeated surficial slope
movements, if not repaired, may represent a threat to the structural integrity of the slope. If this
situation does arise, the slope shall be inspected by a geotechnical engineer. Subsequently,
maintenance may be required in order to prevent the possibility of further surficial or deep seated
slope movements that may be damaging to life and property.
According to the Coastal Zone Atlas of Mason County, Washington, the Project is within and
near terrain labeled `Intermediate' regarding potential landslide activity. Historically,
intermediate terrains have no known landslides. However, this site is considered inherently
hazardous due the existing geology and/ or topography, and additional analyses and
recommendations concerning the slopes are presented herein. A Stability Map from the Coastal
Zone Atlas for the general area of this Project is provided below:
Envirotech Engineering XXX NE North Shore Road
PO Box 984 page 8 Parcel 32207-50-00951
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 March 11,2016
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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 within terrain labeled `highly unstable' and `highly erodible' relating to
soils. However, DNR did not indicated previous landslide activity on or near the Project. A
Resource Map from the DNR website for the general area of this Project is provided below:
Envirotech Engineering XXX NE North Shore Road
PO Box 984 page 9 Parcel 32207-50-00951
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 March 11,2016
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Resource Map from Washington State Department of Natural Resources Website
SOILS—On Resource N13D 01111
Hyd&Soils
H**unstable
H**,Erodible
Mg*.%r Unstable&
Maltly Erodible
No Data or Gravel
Pits
SLOPE—On Resource Jlag ontg
Medium Slope
Instabilitv
_High Slope histaW,
4.1.1 Slope Stability Analysis
Based on site geology, a non-circular slope stability analysis should be performed.
However, the Simplified Bishop Method (circular analysis), as presented herein, was
utilized. Although the method of circles does not fit the site conditions, Envirotech
certifies that our analysis is more conservative for these project conditions than other
Envirotech Engineering XXX NE North Shore Road
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J
conforming slope stability models. For this Project and level of geotechnical
investigation, our conclusions or recommendations would not be changed by this
variation in analysis.Where applicable,our slope stability analysis utilizes the subsurface
angle of repose.
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: 135 pcf
Angle of internal friction: 32 degrees
Cohesion: 0 psf
Soils below 5 feet in depth
Soil unit weight: 140 pcf
Angle of internal friction: 40 degrees
Cohesion: 400 psf
Based on the slope stability analysis, minimum factors of safety were determined to be
less than 1.5 relative to static slope failures, and less than 1.1 with relation to seismic
conditions. These factors of safety were primarily limited to the face of the slope,and 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 1.3 and 1.0, 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 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 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 minor erosion control recommendations provided in this report is sufficient
for the development of this Project, and additional engineered erosion control plans are not
Envirotech Engineering XXX NE North Shore Road
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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.
43 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 Hood Canal Fault Zone, in which is approximately 500 feet to the west 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.
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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
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, additional design parameters must be accounted for
in the retaining wall analysis, and recommendations should only be provided by a qualified
engineer after the type of backfill is acquired, inclination 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.
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5.0 ENGINEERING RECOAOWNDATIONS
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 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. 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 12 inches Q 5 inches for two stories)shall be placed at a minimum of 18
inches below the existing ground surface. 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.
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.
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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.
5.13 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 #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.
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51.2 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 t
FILL
1
I I UNDISTURBED SUBGRA tl.'
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
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
90% 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.
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51.3 Retaining Wall Backfili
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.
53 Building and Footing Setbacks
Due to potential debris flow,the building location should have a minimum setback from the local
ascending slope toe equal to '/2 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
building setback to be at least 25 feet from the toe of the nearby ascending slope. See the Site
Plan in Appendix A for an illustration of the setbacks.
The required setbacks may be reduced, if necessary. The setback for descending slopes may be
decreased by utilizing a deeper foundation, pin-piles,retaining walls or buttressing the slope toe.
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.
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5.4 Surface and Subsurface Drainage
Positive drainage should be provided in the final design for all planned residential buildings.
m e
Drainage shall include sloping the ground surface driveways and sidewalks away from th
g P g gr � Y Y
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 water is infiltrated or dispersed on-site or tightilined to
Hood Canal,conforming to the Mason County Small Parcel Stormwater Plan.
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 is an excellent measure to minimize surficial slope movements and erosion on slope
faces and exposed surfaces. By removing trees, the root strength is decreased over time, thereby
lowering the `apparent' cohesion of the soil. Transpiration is decreased, which results in
additional groundwater, increased pore water pressure and less cohesion/ friction of the soil
particles. Stormwater runoff also increases, and, fewer plants will create less absorption of the
force from raindrops,thereby creating the potential for erosion hazards.
Vegetation Buffer—Vegetation shall not be removed from the critical slope or within a distance
of 10 feet beyond the toe 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.
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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,if necessary.
Permanent erosion control may also be necessary if substantial vegetation has not been
established within disturbed areas upon completion of the Project. Temporary erosion control
should remain in place until permanent erosion control has been established. Permanent erosion
control may include promoting the growth of vegetation within the exposed areas by mulching,
seeding or an equivalent measure. Selected recommendations for permanent erosion control are
provided in Appendix 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. The following Surface and Subsurface Drainage Section may
have additional recommendations with relation to permanent erosion for surface drainage
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 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.
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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
Robert McNearny,E.I.T. Michael Staten,P.E.
Staff Engineer Geotechnical Engineer
Envirotech Engineering XXX NE North Shore Road
PO Box 984 page 20 Parcel 32207-50-00951
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 March 11,2016
APPENDIX A
SITE PLAT!
9 ---N *
SCALE: 1'=80'
EXISTING WELL 0 0 40 80
EXISTING GRAVEL
PROPOSED STRUCTURE DRIVEWAY
PROPOERTY LINE 26' CONSTRUCTION
SETBACK
582t
SILT FENCE -
/ o
p 10' VEGETATED y
/ BUFFER N
y T 2 �/ PROPOSED DRIVEWAY
570f a
n y
P d
A ,49*/ IS6
%A-
1oi I 111�
� � NORTH SHfR
242t
PROPOSED SEPTIC
DRAINFIELD
TOE OF SLOPE TOP OF SLOPE
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. GRANT CALLIN
CONTOURS WERE EXTRAPOLATED FROM A PUBLIC LIDAR SOURCE, AND XXX NE NORTH SHORE ROAD
INCORPORATED FIELD MEASUREMENTS AS EXPLAINED IN THE GEOTECHNICAL LEGEND PARCEL 32207-50-00951
REPORT. MASON COUNTY WASHINGTON
3, BOUNDARIES WERE NOT PREPARED BY A LICENSED SURVEYOR, LOCATIONS TEMPORARY ENGINEER
OF SITE FEATURES THAT ARE SHOWN HERE, SUCH AS TOP OF SLOPES, TOE EROSION CONTROL ENIROTECH ENGINEERING
OF SLOPES, WATER FEATURES, ETC- WITH RELATION TO THE PROPERTY PO BOX 984
LINES MUST BE VERIFIED BY THE OWNER. RECOMMENDATIONS IN THE SLOPE INDICATOR BELFAIR, WASHINGTON 98528
GEOTECHNICAL REPORT PROVIDE SETBACKS, BUFFERS, DEPTHS, ETC.. WITH BELFAI5-9374
RELATION TO GEOLOGIC FEATURES, NOT PROPERTY LINES, THESE GEOLOGIC EXISTING CONTOUR
FEATURES MAY BE LOCATED ON THE SUBJECT PROPERTY OR NEIGHBORING IS�TP TEST PIT SITE PLAN
PROPERTIES.
APPENDIX.B
SOIL INFORMATION
VERTICAL AND HORIZONTAL SCALE,
SCALE; 1'=60'-0'
0 15 30 60
EXISTING GRADE
EXISTING GRADE PROPOSEDHOUSE
SILTY SAND WITH Aql
GRAVEL (SM)
HOOD CANAL
,7
VERY DENSE
GLACIAL OUTWASH
SECTION A-
PROJECT/ OWNER/ LOCATION,
SINGLE FAMILY RESIDENCE
GEOTECHNICAL REPORT
GRANT CALLIN
XXX NE NORTH SHORE ROAD
PARCEL 32207-50-00951
MASON COUNTY, WASHINGTON
NOTESt ENGINEER
1) MINOR GRADE CHANGES REQUIRED IN ORDER TO ACHIEVE ENVIREITECH 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. SOIL PROFILE
TEST PIT LOG
TEST PIT NUMBER TP-1
PROJECT: Callin Geotechnical Report DATE OF LOG: 10/26/2016
PROJECT NO: 1617 LOGGED BY.- RJM
CLIENT: Grant Callin EXCAVATOR: N/A
LOCATION: Parcel 32207-50-00951 DRILL RIG. None
Mason County, Washington ELEVATION: N/A
INITIAL DEPTH OF WATER.- N/A FINAL DEPTH OF WATER: N/A
SOIL STRATA, STANDARD PENETRATION TEST
DEPTH SAMPLERS USCS DESCRIPTION LL PI CURVE
AND TEST DATA DEPTH N 10 30 50
0
SM Reddish Brown, moist, loose to medium
dense SILTY SAND with GRAVEL.
Gravel is primarily poorly-graded and
1
- subrounded. Sand is mostly medium.
Low plasticity.
2
3
4
5
Excavation terminated at approximately
5.0 feet
6
7
8
9
10
No Groundwater Encountered ENVIROTECH ENGINEERING
This information pertains only to this boring and should not be Geotechnical Engineering
interpreted as being indicitive of the entire site.
TEST PIT LOG
TEST PIT NUMBER TP-2
PROJECT: Callin Geotechnical Report DATE OF LOG: 10/26/2016
PROJECT NO: 1617 LOGGED BY: RJM
CLIENT: Grant Callin EXCAVATOR: N/A
LOCATION: Parcel 32207-50-00951 DRILL RIG: None
Mason County, Washington ELEVATION: N/A
INITIAL DEPTH OF WATER: N/A FINAL DEPTH OF WATER: N/A
SOIL STRATA, STANDARD PENETRATION TEST
DEPTH SAMPLERS USCS DESCRIPTION LL PI CURVE
AND TEST DATA DEPTH N 10 30 50
0
SM Reddish Brown, moist, loose to medium
dense SILTY SAND with GRAVEL.
Gravel is primarily poorly-graded and
1 subrounded_ Sand is mostly medium.
Low plasticity.
2
3
4
5 -
Excavation terminated at approximately
5.0 feet
6
7
8
9
- 10
No Groundwater Encountered ENVIROTECH ENGINEERING
This information pertains only to this boring and should not be Geotechnical Engineering
interpreted as being indicitive of the entire site
Map Unit Description:Rough broken land--Mason County,Washington
Mason County, Washington
Rb—Rough broken land
Map Unit Setting
National map unit symbol. 2hmr
Mean annual precipitation: 50 inches
Mean annual air temperature: 50 degrees F
Frost-free period: 180 days
Farmland classification. Not prime farmland
Map Unit Composition
Rough broken land and similar soils: 100 percent
Estimates are based on observations, descriptions, and transects of the
mapunit.
Description of Rough Broken Land
Typical profile
H1 - 0 to 4 inches: gravelly loam
H2-4 to 43 inches: very gravelly loam
H3-43 to 60 inches: very gravelly sandy loam
Properties and qualities
Slope: 45 to 90 percent
Depth to restrictive feature: 20 to 72 inches to densic material
Natural drainage class: Well drained
Capacity of the most limiting layer to transmit water(Ksat):
Moderately high to high (0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water storage in profile: Low(about 3.2 inches)
Interpretive groups
Land capability classification(irrigated): None specified
Land capability classification(noniaigated). 7e
Hydrologic Soil Group: B
Data Source Information
Soil Survey Area: Mason County,Washington
Survey Area Data: Version 11, Sep 15, 2015
USDA Natural Resources Web Soil Survey 2/18/2016
Conservation Service National Cooperative Soil Survey Page 1 of 1
Please print, sign and return to the Department of Ecology
Water Well Report Current
L.0 Original-Ecology, 161 copy-owner,2ad copy-driller Notice of Intent No. W ]S9415
t iTc'i Unique Ecology Well ID Tag No.ALB 204
N Construction/Decommission
®Construction Water Right Permit No.
❑ Decommission ORIGINAL INSTALLATIONNotice Property Owner Name Gary IQCkard
4) 1 UOU� of Intent Number Well Street Address 21901 NE North Shore W.
? 1
y PROPOSED USE: [Domestic ❑ Industrial ❑ Municipal City Tahuya County
❑DeWaler ❑Irrigation ❑Test Well ❑Other
t Locatio&X_1/4-1/4N _1/4 Sec_ Twn22 RjHj EwM Lek
4.0 TYPE OF WORK: Owner's number of well(if more than one) wwm one
C New well ❑Reconditioned Method:❑Dug ❑ Bored ❑ Driven
O �Deepened KlCable ❑Rotary [I Jetted
Lat/Long(s,t,r Lat Deg Lat Min/Sec
C DIMENSIONS: Diameterofwell inches,drilled 1 rci--ft. Still REQUIRED Long Deg Long Min/Sec
0 Depth of completed well
a+ CONSTRUCTION DETAILS Tax Parcel No. -207-50 00914
Casing Welled �j Diam.from-+1-ft.to 1 513 ft.
L Installed: Liner installed Diam.from ft.to ft. CONSTRUCTION OR DECOMMISSION PROCEDURE
O Threaded Diam.from ft-to ft.
C Perforations: ❑Yes No Formation: Describe by color,character,size oFnutlerial and structure,and the kind and
nature of the material in each stratum penetrated,with at least one entry for each change of
Type of perforator used information indicate all water encountered. (USE ADDITIONAL SHEETS IF NECESSARY.)
a SIZE of perfs in.by_in.and no.of perfs_from_ft.to_ft. MATERIAL FROM TO
�i Screens: []Yes Ud No ❑K-Pac Location
O Manufacturer's Name 0 55
Type Model No.
'a Diam. Slot size From ft.to ft.
C Diam. Slot size from ft.to ft. Redi
Gravel/Filter packed:❑Yes QNo [:]Size of gravel/sand
Materials placed from ft.to ft. Brown
.I..e n
Surface Seal::W Yes []No To what depth? a ft.
Material used in seal Bell-oni to
Did any strata contain unusable water? ❑Yes Rl No
Js..1 Type of water? Depth of strata
Method of sealing strata off
C PUMP: Manufacturer's Name (�rsl rlo
cc Type L �_ H.P.
L
16- WATER LEVELS: Land-surface elevation above mean sea level ft.
cc Static level 93 ft.below top of well Date
Artesian pressure lbs.per square inch Date
-
Artesian Artesian water is controlled by
(cup,valve,etc.)
Z WELL TESTS: Drawdown is amount water level is lowered below static level
Was a pump test made?❑Yes ®No if yes,by whom?
Yie{J: eal.lmin.with ft.drawdown after hrs.
0 O
Yield: gal./min.with ft.drawdown after hrs.
Yield: eallmin.with ft.druwdown after hrs. ir
Recovery data(Hine taken m•zero when pump turned off)(water Level meusuredJrom well - -
top to water level) -
0 Time Water Level Time Water Level Time Water Level
O
0
LU
Date of test W
O Bailer test galimin.with 52 ft.drawdown after _hrs.
= Airtest gal./min.with stem set at ft.for hrs.
�'' Anestan now a.p.m. Date
ETemperature of water Was a chemical analysis made? ❑Yes ❑[No
L Start Date 4�27�Q4 Completed Date
CL WELL CONSTRUCTION CERTIFICATION: 1 constructed and/or accept responsibility for construction of this well,and its compliance with all
4) Washington well construction standards. Materials used and the information reported above are true to my best knowledge and belief.
1 Driller/Engineer/Trainee Name(Print f)warle 1{nApp Drilling Company Thesis, Drilling
Driller/Engineedfrainee Signature .L&Q�w+ �, Address 340 NEDidVl G Farm Rf�
Driller or trainee License No. 1706 City,State,Zip }3P1fairr WA 9AS?R
Contractor's
If TRAINEE DAVISDII 1 OOA
Driller's Licensed No. _ Registration No. Datey04
Driller's Signature Ecology is an Equal Opportunity Employer. ECY 050-1-20(Rev 2/03)
APPENDIX C
SLOPE STABILITY
I�
STABLE Slope Stability Analysis System
New User
Project Callin
Datafile: Dynamic Bishop
STABLE Version 9.03.00u
Bishop
xx+x*++**x*xxxxx+*x+xxxx+x+#+*xxxx*xx*xxxx+++#****+*x+++x+
TITLE
Dynamic
UNITS (Metric/Imperial) - I
GEOMETRY DEFINITION
POINTS
NO. X Y
1 0.000 0.000
2 25.000 0.000
3 152.000 -60.000
4 212.000 -60.000
5 0.000 -8.000
6 25.000 -8.000
7 152.000 -68.000
8 212.000 -68.000
9 21.200 0.000
10 30.130 -2.420
11 39.050 -6.640
12 47.980 -10.860
13 56.910 -15.070
14 65.830 -19.290
15 74.760 -23.510
16 83.680 -27.720
17 92.610 -31.940
18 101.540 -36.160
19 110.460 -40.380
20 119.390 -44.590
21 128.320 -48.810
22 137.240 -53.030
23 146.170 -57.240
24 155.090 -60.000
25 164.020 -60.000
26 172.950 -60.000
27 181.870 -60.000
28 190.800 -60.000
LINES
Lo X Hi X SOIL
1 2 1
2 3 1
3 4 1
5 6 2
6 7 2
7 8 2
++##RR+*******+***************+*RR**R***+***+++#++****+##+
SOILS
SOIL NAME LINETYPE-PEN COHESION FRICTION UNIT WT.
STABLES2002 W Associates Ltd Printed on: 18/02/16 @ 13:42:05 Page' 1
STABLE Slope Stability Analysis System
New User
Project Callin
Datafile: Dynamic Bishop
1 SM CONTINUOUS-BLACK 0.00 32.0 135.000
2 Hardpan CONTINUOUS-BLUE 400.00 40.0 140.000
PORE PRESSURE SPECIFICATION
SOIL PIEZO RU EXCESS
Y/N/P Value Value
1 N 0.000 0.000
2 N 0.000 0.000
PIEZOMETRIC SURFACE
POINT
POINT PORE PRESSURES
POINT PRESSURE
SLIP DIRECTION (+/- X) _ +
SLIP-CIRCLES
AUTOMATIC
Circle Centre Grid Extremities
169.600
* *
21.200 * * 190.800
# k
0.00L
X spacing -- no. of cols (max 10)- 10
Y spacing -- no. of rows (max 20)= 20
Grid 1 Circles through point 9
Grid 2 Circles through point 10
Grid 3 Circles through point 11
Grid 4 Circles through point 12
Grid 5 Circles through point 13
Grid 6 Circles through point 14
Grid 7 Circles through point 15
Grid B Circles through point 16
Grid 9 Circles through point 17
Grid 10 Circles through point 18
Grid 11 Circles through point 19
Grid 12 Circles through point 20
Grid 13 Circles through point 21
Grid 14 Circles through point 22
STABLE02002 MZAssociates Ltd Printed on: 18/02/16 @ 13:42:05 Page: 2
1 . 00
1. . 10
1 _ 2 0
1 _ 3 0
1 _ 40
1 . 50
'1 _ 60
1 . 70
1 80
1 _ 0
2 . 00
1 _ 0 3
Project _ Ca11in
D a t a f i 1 e _ D y n a m i c
Analysis Bishop
STA8LE.-2002 MZ Associat�� Ltd
r
1 . 00
1 . 10
1 . 2 0
1 . 3 0
1 . 40
1 . so
1 . 60
1 . 7 0
1 . 8 0
1 . 90
=2 . 00
A k\
1 3 6
P r o j e c t Ca p i n
Datafila Static
Analysis Bishop
S AE+ E-2UU2 MZ Aaaoclatva LYd
APPENDIX D
EROSION CONTROL
1
p ,
GEOTEXTILE FABRIC GEOTEXTILE FABRIC
WRAP AROUND TRENCH 2'x2' WOOD POST BETYP) AND WIRE MESH
TO AT LEAST ENTIRE OR EQUIVALENT OR BETTER
BOTTOM OF TRENCH E 6 FT MAX. D.C. 0.5 FT
BEFORE PLACING GRAVEL 2'x2'x5' WOOD POST OR �-�— 6 FT —�
12' DEEP, 8' WIDE TRENCH EQUIVALENT OR BETTER EXISTING rl
FILLED WITH 3/4' TO 1 1/2' GROUND SURFACE
WASHED GRAVEL or VEGETAT N 2 T
DIRECTION OF 2.5 FT 12' DEEP, 8' WIDE
WATER FLOW GROUND SURFACE EXISTING TRENCH FILLED WITH 1 T
12' 3/4. 70 1 1/2' 2.5 FT
2.5 FT WASHED GRAVEL OR
I VEGETATION
-�Ig• BOTTOM EXTENTS OF
II GEOTEXTILE FABRIC SILT FENCE - DETAIL
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
1, SHOULD THE TEMPORARY EROSION AND SEDIMENT CONTROL MEASURES SHOWN ON COARSE MATERIAL.
THESE PLANS PROVE TO BE INADEQUATE DURING CONSTRUCTION, THE CONTRACTOR 2. APPLY AT APPROXIMATELY 75 TO 100 POUNDS PER 1000 SQUARE
SHALL INSTALL ADDITIONAL EROSION AND SEDIMENT CONTROL FACILITIES. FEET OF GROUND.
2. ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE 3. MINIMUM THICKNESS SHALL BE 2 INCHES.
INSPECTED DAILY AND IMMEDIATELY MAINTAINED, IF NECESSARY. 4. HAY OR STRAW IS SUBJECT TO BLOWING. KEEP MOIST OR TIED
3. ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE LEFT INDOWN.
PLACE UNTIL THE UPSLOPE AREAS HAVE BEEN PERMANENTLY STABILIZED. PERMANENT EROSION CONTROL NOTES,
TEMPORARY EROSION CONTROL NOTES,
FOR ALL AREAS WHICH HAVE BEEN STRIPPED OF VEGETATION OR EXPERIENCED LAND SEEDING FOR RAW SLOPES
DISTURBING ACTIVITIES, AND WHERE NO FURTHER WORK IS ANTICIPATED FOR A 1. BEFORE SEEDING, INSTALL NEEDED SURFACE RUNOFF CONTROL
PERIOD EXCEEDING THE LISTED CRITERIA BELOW, ALL DISTURBED AREAS MUST BE MEASURES SUCH AS GRADIENT TERRACES, INTERCEPTOR DIKES,
IMMEDIATELY STABILIZED WITH MULCHING, GRASS PLANTING OR OTHER APPROVED SWALES, LEVEL SPREADERS AND SEDIMENT BASINS.
EROSION CONTROL TREATMENT APPLICABLE TO THE TIME OF YEAR. GRASS SEEDING 2. THE SEED BED SHALL BE FIRM WITH FAIRLY FINE SURFACE,
ALONE WILL ONLY BE ACCEPTABLE DURING THE MONTHS OF APRIL THROUGH FOLLOWING SURFACE ROUGHENING. PERFORM ALL OPERATIONS ACCROSS
SEPTEMBER. HOWEVER, SEEDING MAY PROCEED WHENEVER IT IS IN THE INTEREST OF OR PERPENDICULAR TO THE SLOPE.
THE OWNER/CONTRACTOR, BUT MUST ALSO BE AUGMENTED WITH MULCHING, NETTING 3, SEEDING RECOMMENDATIONS, AS SHOWN BELOW, AND SHOULD BE
OR OTHER APPROVED TREATMENT. APPLIED AT THE RATE OF 120 POUNDS PER ACRE.
DRY SEASON (MAY 1 THRU SEPTEMBER 30) -- THE CLEARING OF LAND, INCLUDING THE 4. SEED BEDS PLANTED BETWEEN MAY 1 AND OCTOBER 31 WILL
REMOVAL OF EXISTING VEGETATION OR OTHER GROUND COVER, MUST BE LIMITED TO REQUIRE IRRIGATION AND OTHER MAINTENANCE AS NECESSARY TO
ONLY AS MUCH LAND AS CAN RECEIVE APPROPRIATE PROTECTIVE COVER OR BE FOSTER AND PROTECT THE ROOT STRUCTURE.
OTHERWISE STABILIZED, AFTER HAVING BEEN CLEARED OR OTHERWISE DISTURBED , 5. SEED BEDS PLANTED BETWEEN N BE NE ER 1 AND APRIL 30,
BY NO LATER THAN SEPTEMBER 30 OF A GIVEN YEAR. UNLESS IMMEDIATE GEOTEARMORING OF THE SEED BED WILL BE NECESSARY, (e.g.,
STABILIZATION IS SPECIFIED IN THE EROSION AND SEDIMENT CONTROL PLAN, ALL 6. FER FERTILIZERS
JUTE MAT, CLEAR PLASTIC COVERING).
AREAS CLEARED OR OTHERWISE DISTURBED MUST BE APPROPRIATELY STABILIZED 6. FERTILIZERS ARE TO BE USED ACCORDING IZ SUPPLIERS'
THROUGH THE USE OF MULCHING, NETTING, PLASTIC SHEETING, EROSION BLANKETS, RECOMMENDATIONS. AMOUNTS SHOULD T MINIMIZED, ESPECIALLY
FREE DRAINING MATERIAL, ETC., BY SEPTEMBER 30 OR SOONER PER THE APPROVED ADJACENT TO WATER BODIES AND WETLANDS.
PLAN OF ACTION, UNLESS OTHERWISE APPROVED BY THE COUNTY, SEEDING, USE THE FOLLOWING RECOMMENDED SEED MIXTURE FOR EROSION
FERTILIZING AND MULCHING OF CLEARED OR OTHERWISE DISTURBED AREAS SHALL BE CONTROL, OR A COUNTY APPROVED ALTERNATE SEED MIXTURE.
PERFORMED DURING THE FOLLOWING PERIODS: MARCH I TO MAY 15, AND AUGUST 15 TO
OCTOBER 1. SEEDING AFTER OCTOBER 1 WILL BE DONE WHEN PHYSICAL COMPLETION PROPORTIONS PURITY GERMINATION
OF THE PROJECT IS IMMINENT AND THE ENVIROMENTAL CONDITIONS ARE CONDUCIVE NAME BY WEIGHT(%) (%) (7)
TO SATISFACTORY GROWTH. IN THE EVENT THAT PERANENT STABILIZATION IS NOT
POSSIBLE, AN ALTERNATIVE METHOD OF GROUND COVER, SUCH AS MULCHING, NETTING, REDTOP (AGROSTIS ALBA) 10 92 90
PLASTIC SHEETING, EROSION BLANKETS, ETC., MUST BE INSTALLED BY NO LATER THAN ANNUAL RYE (LOLIUM MULTIFLORUM) 40 98 90
SEPTEMBER 30.
CHEWING FESUE 40 97 80
IN THE EVENT THAT CONSTRUCTION ACTIVITIES OR OTHER SITE DEVELOPMENT (JAMESTOFESTUCA RUBRA COM, S ADO
ACTIVITIES ARE DISCONTINUED FOR AT LEAST 4 CONSECUTIVE DAYS, THE WHITE
BANNER, SHADOW, KOKET)
OWNER/CONTRACTOR SHALL BE RESPONSIBLE FOR THE INSPECTION OF ALL EROSION WHITE DUTCH CLOVER 10 96 90
AND SEDIMENT CONTROL FACILITIES IMMEDIATELY AFTER STORM EVENTS, AND AT CTRIFOLIUM REPENS)
LEAST ONCE EVERY WEEK. THE OWNER/ CONTRACTOR SHALL BE RESPONSIBLE FOR MULCHING
THE MAINTENANCE AND REPAIR OF ALL EROSION AN SEDIMENT CONTROL FACILITIES.
WET SEASON (OCTOBER 1 THRU APRIL 30> -- ON SITES WHERE UNINTERUPTED 1. MATERIALS USED FOR MULCHING ARE RECOMMENDED TO BE WOOD
CONSTRUCTION ACTIVITY IS IN PROGRESS, THE CLEARING OF LAND, INCLUDING THE FIBER CELLULOSE, AND SHOULD BE APPLIED AT A RATE OF 1000
POUNDS PER ACRE.
REMOVAL OF EXISTING VEGETATION AND OTHER GROUND COVER, SHALL BE LIMITED
TO 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
THE EVENT A MAJOR STORM IS PREDICTED AND/ OR EROSION AND SEDIMENT GREATER THAN 2-1 (HORIZONTAL-VERTICAL).
ICAL).
I
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
ALL CLEARED OR DISTURBED AREAS SHALL RECEIVE APPROPRIATE PROTECTIVE AREAS REQUIRING MULCH SHALL BE COVERED BY NOVEMBER 1.
COVER OR BE OTHERWISE STABILIZED, SUCH AS MULCHING, NETTING, PLASTIC
SHEETING, EROSION BLANKETS, FREE DRAINING MATERIAL, ETC., WITHIN 5 DAYS AFTER
HAVING BEEN CLEARED OR OTHERWISE DISTURBED IF NOT BEING ACTIVELY WORKED.
SILT FENCING, SEDIMENT TRAPS, SEDIMENT PONDS, ETC., WILL NOT BE VIEWED AS
ADEQUATE COVER IN AND OF THEMSELVES. IN THE EVENT THAT ANY LAND AREA NOT
BEING ACTIVELY WORKED REMAINS UNPROTECTED OR HAS NOT BEEN APPROPRIATELY
STABILIZED 5 DAYS AFTER HAVING BEEN CLEARED, ALL CONSTRUCTION ACTIVITY ON
THE SITE, EXCEPT FOR APPROVED EROSION AND SEDIMENT CONTROL ACTIVITY, SHALL
IMMEDIATELY CEASE UNTIL SUCH A TIME AS AFOREMENTIONED LAND AREA HAS BEEN
APPROPRIATELY 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 GRANT CALLIN
TOGETHER ONLY AT A SUPPORT POST WITH A MINIMUM 6-INCH OVERLAP AND SECURELY FASTENED AT XXX NE NORTH SHORE ROAD
BOTH ENDS TO THE POST. PARCEL 32207-50-00951
3. STANDARD FILTER FABRIC SHALL BE FASTENED USING V STAPLES OR TIE WIRES (HOG RINGS) 2 4 IN MASON COUNTY, WASHINGTON
PACING.
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'X14 GAUGE OR EQUIVALENT. THE WIRE MESH MAY BE ELIMINATED IF PO BOX 984
XTRA-STRENGTH FILTER FABRIC (MONOFILAMENT), AND CLOSER POST SPACING IS USED. BELFAIR, WASHINGTON 98528
A TRENCH SHALL BE EXCAVATED ACCORDING TO THE DETAILS ON THIS SHEET ALONG THE LINE OF THE 360-275-9374
OSTS AND UPSLOPE FROM THE SILT FENCE.
SILT FENCES SHALL BE LOCATED DOWNSLOPE FROM THE CLEARING LIMITS OF THE PROJECT. ER❑SI❑N CONTROL