HomeMy WebLinkAboutGEO2014-00001 - BLD Engineering / Geo-tech Reports - 11/25/2013 Ewvirote C,k �wg�weer�wg
cJeotechwicaL ° AYa%wA9E°Roadway
April 3,2014
Terry Davis
5013 100 Street SW
Mukilteo,Washington 98275
RE: Geotechnical Inspection for Property Located at 123 E Orre Nobles Road,Union Washington
Dear Mr.Gallagher,
Envirotech Engineering (Envirotech) completed a site visit, general surface conditions inspection and
conclusions for the single family:residential development at the referenced location. The site inspection
was conducted on March 28, 2014 in order to observe surface conditions, and assess the development
from a geotechnical standpoint. Specifically,we inspected buffers,setbacks and general earthwork for the
project. The original geotechnical report, dated November '25, 2013, was prepared by Envirotech.
Information pertaining to the project was provided by Mr. Davis,proponent of the property. Information
collected from site observations was completed by Michael Staten with Envirotech.
With relation to our original geotechnical design report, vegetation buffers and building setbacks were
inspected to be in compliance. Although we were not present on-site during the construction phase thus
far, it is apparent that earthwork is also in compliance with our original report. This is based on our
surface observations, and information from the proponent. It is our opinion that nearby slopes has
increased stability due to the recent earthwork.
All future development, including a future garage and additional work to the residence should follow the
guidance in the geotechnical report. It is important for the homeowner to maintain drainage facilities,and
maintain vegetation after it is established. The homeowner should notify Envirotech in the event of
excessive erosion,Toughing of the slope,or drainage problems.
If you have any questions or need any further assistance,please contact Michael Staten at 360-275-9374.
Sincerely,
Envirotech Engineering
by CLYDE s
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Michael Staten,P.E.
Project Director
Po�oxy8�
Selfatr,wash%v�.gtow98528
Q ff: 360-2�593�4
CdL: 360-609-6045
day.: 360-2�5-4�8,y
ewJ�rotech@gtotechwical.iw fo.covu
Geotechnical Report
for
Single Family Residential Property
123 E Orre Nobles Road
Union, WA 98592
Parcel 32232-50-87005 & -87006
• Mason County, Washington
November 25, 2013
Project# 13107
Prepared For:
PAL CLYDe ST
Terry Davis ,�'� of WAS
5013 104`" Street SW
Mukilteo, WA 98275
� 43045 Q q�
Prepared By: 01- FcISTIV G`�4
NALtiN
Envirotech Engineering
PO Box 984
Belfair, Washington 98528
Phone: 360-275-9374
Fax: 360-275-4789
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: J Q� / l • 1/�C
Permit# � `. 0000 Parcel#
Date(s) of the Documenf(t evie�DD
(1) (a)A discussion of general geologic conditions in the vicinity of the proposed development,
OK? Comment:
(b) A disc sion of specific soil types
OK? Comment:
(c) A disc ssion of ground.water conditions.
OK?V Comment: -
(d) A disc ss'ion of the upslope geomorphology
OK?V Comment:
(e) A disc ssion of the location of upland waterbodies and wetlands
OK? v Comment:
(f) A discussion of history of landslide activity in the activity in the.vicinity, as available in the
referen d maps and recor CQ
OK? V Comment:
(2) A site plan Which identifies thd important evelopment and geologic features.
OK? Comment:
(3) Locations apd logs of exploratory o s or probes.
OK? ►/ Comment:
(4) The area of the,proposed development, the boundaries of the hazard, and associated buffers and
setbacks sh be delineated(t hi s' s, and toe)on a geologic map of the site.
OK? Comment: �]
(5) A minimum of one cross se tion at a scale which adequately depicts the subsurface profile, and
which incor rates the details of proposedrade changes.
OK. Comment:
(6) A description and results of slopes Iity 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 safe actor is 1.1.and the u i- tqfjc analysis coeffients should be a value of 0.15.
OK? Comment:
(7) (a)Approp�i6fe restrictions on placemUt of drainage features
OK? V Comment:
(b) ApproVate restrictions on placement of septic drain fields
OK? V Comment:
(c) Approp ate restrictions on placement of compacted fills and footings
OK?Comment:
(d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other
slopes on the property.
Pagel of 2 Form Effective June 2008
OK? tl Comment: p1 vy
(e) Recommended setbaack from the landslide hazard areas shoreline bluffs and the tops of
Other sl es on the property
OK? omment:
(8) Recommendations for the preliaration 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? 1/ Comment:
(9) Recommendations for the prepa at on of a detailed temporary erosion control plan which
identifies the specific mitigating measures to be implemented during construction to protect the
slope from rosion, landslides and harmful construction methods.
OK?Comment:
(10) An analysis of both on-site and off-site impacts of the proposed development.
OK?7 Comment:
(11) Specifications of final development conditions such as, vegetative management, drainage,
erosion co trol, and buffer widths.
OK? Comment:
(12) Recommendations for the preparation of structural mitigation or details of other proposed
mitigatio
OK? Comment:
(13) A site map d awn to scale showing the property boundaries, scale, north arrow, and the location
and nature f existing and prop s y#dev I ment on the site.
OK? Comment: �Y
—�— p/f
Are the Documents signed and stamped? V.
Type and #of License: C ✓` "' 4144 .
I.f.not approved, what is the next action/recommendation for further action?
Reviewed by , on
Time spent in review:
SECOND REVIEW/UPDATE:
Reviewed by , on
Time spent in second review:
THIRD REVIEW/ UPDATE:
Reviewed by , on
Time spent in third review:
Disclaimer: Mason County does not certify the quality of the work done in this Geological Assessment
Page 2 of 2 Form Effective June 2008
i
Mason, County Department of Community Deveiopment
jUu;riitrai vi:@GKiiSi For a Geoiechnlcai Repo%
Instructions:
This checklist must be submitted with a Geotechnical Report and completed, signed, and stamped by the
licensed professional(s)who prepared the Geoiechnical Report for review by Mason County pursuant to
the OnUinance. If ap.i are 490aind to be not applicable, the report should explain
the basis for the conclusion.
ApplicanVOH1iner I P�(+r 0ck y_ ) Parcel#
Site Auui-ess 1 .3 i�-7 OTC 106k 0'1
(1) (a)A discussion of general geologic conditions in the vicinity of the proposed development,
Located on page(s)___ 19
(b) A discussion of specific son-types
Located on pape(s)
(c) A discussion of ground wafer conditions
Located on. page(S)
(d) A discussion of the upslope geomorphology
Located on pagets) 3
(eI A discussion of tine!ccation of upland waterbodies and wetlands
Located on page(s) tr
(ijj ,u, uiscus5it;i.u nisCJr y of 7ancistiOe activity in the activity in the vicinity,as available in the
referenced maps and records
Locorcd or, pago(s? 5, /o
(2) A site plan which identifies the im�-or'ant development and geologic features.
Located on Map(s) 4e F'ldij
(3) Locations and logs of explorat ry hp les or probes
Lvc;SGu or f iVd{�i�j S•'�- ��
(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.
L.QGated CII iViep(s) 7,-f2, ('Ian
(5) A rninirrium of one cross section at a scale which adequately depicts the subsurface profile, and
which incorporates the details-of proor7,^sed grade changes.
�O uatect 011 n apk f .r7�rnr�1'�
-A riGc fi n = cst1'C r-L �L k- :
Trip.e anal �t..of sl cs st2biiitt.analvsns perforated•,r ,�o=-:s1Tf:w and seismic
conditions.Analysis should examine worst case failures_The analysis should include the
1Iff,;aQ, SisInaWS --to'i od Of v4�.Xas-The ai4u ft-,i um static safety factor is'6_a,the ri k tnum
seismic safety factor is 1-1-and the quasi-static analysis coeffrents should be a value of 0-15.
Located on pages) 1 L, c<Cn, G
(7) (a) Appropriate- restrictions on placement of drainage features
Located on page(s) i9
(b) Appropriat-e:astinc;ions on piao-cement of septic drain fields
Located on page(s) Z
(c) .%pp,opriaie restrictions on placement of compacted fills and footings
Located on page(s) t 6,
Page 1 of 2 Form Effective June 2008
Jisclair—ner: Mason County does not certify fhe rlualif/of the work dome in this r?eote^f:~iw i f'en--
(d) Recommended buffers from the landslide hazard areas shoreline-bluffs and the tops of other
slopes on the property.
Located on page(s) 20
(e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of
other slopes on the property.
Located on page(s) 19
(8) Recommendations for the preparation of a derailed clearing and grading pian Whic;ch spec i ically
identifies vegetation to be removed, a schedule for vegetation removal and replanting, and the
method of vegetation removal.
Located on page(s) 20
(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
siope from erosion, iandslides and harmful construction methods.
Located on page(s) 1 3.
(-iu) An analysis of both on-site and off-site impacts of the proposed development.
Located on page(s) 1 S
(,i i) Specifications of final development conditions such as, vegetative management, drainage,
erosion control, and buffer widths.
Located on page(s) 19 r 2
(12) Recommendations for the preparation of structural mitigation or details of other proposed
mitigation.
Located on page(s) 2(
(13) A site map drawn to scale showing the pfQperty-Oundaries,scale.north arrow, and the location
and nature of existing and pro used development on the site.
eot;uiedorsWap(s') S;fe- 0V\
hereby certi-t l Y under pena of
Perjury gnat i a�m a cMi engineer licensed i_n the State of Washington wifh specialized imowiedge of
geotechnicall'-eologicai angin6Zaring or a geologist or rarigir�"'ing geologist iioartaed ar s a ate Of
u::Ki• ie4.Y '.a:ra�.��S t'fl ': ?7'=iilFS. z-a ejerw tlai�1i'z"T_-£s-M`IiJl!cc'
Report. datedl.IEod 2S 20i3 , and entitled �� ;�� / � � �'��.ai �✓o('%i'Ty
�23 E Orin Alb UO& ReJ rneels SH ii?a Pefiu�'r`Paieeairi GI Me avlasoii
County Resource Ordi is ce.Lam'slide Hazard Simon. is complete and true,-fi;at assessment
demonstrates conclusively that the risks posed by the landslide hazard can ba me itipated thimough the
includeai$EOI iaruca!aeSigro a B%ir�iaei72iaisr_ aeS,ar ua mot all ha�f"as ale eiiiugatec.in slag-i a manner as
Zo preeve±t hen io properho and pub3v;lses�h! �`a5dlez'1)
CT.Y1)1-
�? 43045
.�`rsJONAL_�
lv i
Page 2 of 2 Form Effective June 2008
Disc!ai ner: Mason County does not cortify th-quality of the work done In this GWec'intcal Repo"
TABLE OF CONTENTS
1.0 INTRODUCTION..................................................................................................................................1
1.1 PROJECT INFORMATION.....................................................................................................................1
1.2 PURPOSE OF INVESTIGATION AND SCOPE OF WORK.........................................................................1
2.0 SURFACE CONDITIONS....................................................................................................................3
2.1 GENERAL OBSERVATIONS..................................................................................................................3
2.2 TOPOGRAPHY......................................................................................................................................3
2.2.1 Upslope Geomorphology.............................................................................................................3
2.3 SURFACE DRAINAGE...........................................................................................................................3
2.3.1 Upslope Water Bodies.................................................................................................................4
2.4 SLOPE AND EROSION OBSERVATIONS................................................................................................4
3.0 SUBSURFACE INVESTIGATION......................................................................................................5
3.1 FIELD METHODS,SAMPLING AND FIELD TESTING............................................................................5
3.2 GENERAL GEOLOGIC CONDITIONS....................................................................................................5
3.3 SPECIFIC SUBSURFACE CONDITIONS..................................................................................................6
3.3.1 Groundwater...............................................................................................................................8
4.0 ENGINEERING ANALYSES AND CONCLUSIONS.......................................................................9
4.1 SLOPE STABILITY................................................................................................................................9
4.1.1 Slope Stability Analysis.............................................................................................................12
4.2 EROSION............................................................................................................................................13
4.3 SEISMIC CONSIDERATIONS AND LIQUEFACTION.............................................................................13
4 3.1 Liquefaction..............................................................................................................................14
4.4 RETAINING WALLS AND LATERAL EARTH PRESSURES...................................................................15
4.5 ON-SrrE AND OFF-SITE IMPACTS.....................................................................................................15
5.0 ENGINEERING RECOMMENDATIONS.......................................................................................16
5.1 BUILDING FOUNDATION RECOMMENDATIONS................................................................................16
5.1.1 Bearing Capacity.......................................................................................................................16
SL2 Settlement..................................................................................................................................17
5.L3 Concrete Slabs-on-Grade..........................................................................................................17
5.2 EARTHWORK CONSTRUCTION RECOMMENDATIONS......................................................................17
5.2.1 Excavation.................................................................................................................................17
5.Z2 Placement and Compaction of Native Soils and Engineered Fill...........................................18
5.23 Wet Weather Considerations....................................................................................................19
5.Z4 Retaining Wall Backfill............................................................................................................19
5.3 BUILDING AND FOOTING SETBACKS.................................................................................................19
5.4 SURFACE AND SUBSURFACE DRAINAGE...........................................................................................19
5.5 VEGETATION BUFFER AND CONSIDERATIONS.................................................................................20
5.6 TEMPORARY AND PERMANENT EROSION CONTROL.......................................................................20
4 2.1 Temporary Erosion Control.....................................................................................................20
4 2.2 Permanent Erosion Control.....................................................................................................20
5.7 SEPTIC DRAINFIELDS........................................................................................................................21
5.8 STRUCTURAL MITIGATION...............................................................................................................21
6.0 CLOSURE............................................................................................................................................22
Appendix A-Site Plan
Appendix B-Soil Information(Soil Profile;Soil Logs;Well Reports)
Appendix C-Slope Stability Input&Output
Appendix D-Erosion Control
Appendix E-Drainage Details
1.0 INTRODUCTION
Envirotech Engineering (Envirotech) has completed a geotechnical investigation for a planned
single family residential replacement/remodel and future detached garage located at 123 E Orre
Noble Road, identified as parcel numbers 32232-50-87005 (garage)and 32232-50-87006(house),
in Union, Mason County, Washington, Section 33, Township 22 North, Range 3 West,
Willamette Meridian. 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,
Terry Davis, in support of the proposed development as detailed below.
An initial geotechnical evaluation of the Project was conducted by Envirotech on October 29'h,
2013. 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 property consists of an existing cabin, septic system and other ancillary features.
The proposed development is expected to consist of partially replacing and remodeling the house,
and constructing a new detached garage. 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
Envirotech Engineering Teny Davis Geotechnical Report
PO Box 984 page 1 123 E Orre Noble Road
Belfair,Washington 98528 Parcel 32232-50-87005&-87006
Ph. 360-275-9374 Union,Mason County,Washington
Fax:360-275-4789 November 25,2013
proposed improvements of the Project include:
• Review project information provided by the Project owner and/ or owner's
representative;
• Conduct a site visit to document the site conditions that may influence the construction
and performance of the proposed improvements of the Project;
• Define general subsurface conditions of the site by observing subsoils within test pits
and/ or cut banks, review geological maps for the general area, research published
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.
• EORr...i
p Project
/ ItMILLER A
E NRAOUEAVE I
EIMfOMA
0
Vicinity Map from Mason County Website
Envirotech Engineering Terry Davis Geotechnical Report
PO Box 984 page 2 123 E Orre Noble Road
A Belfair,Washington 98528 Parcel 32232-50-87005&-87006
Ph. 360-275-9374 Union,Mason County,Washington
Fax:360-2754789 November 25,2013
2.0 SURFACE CONDITIONS
Information pertaining to the existing surface conditions for the Project was gathered on October
29`h , 2013 by Michael Staten, geotechnical engineer with Envirotech. During the site visit, the
type of geotechnical investigation was assessed, site features were documented that may
influence construction, and 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 East Orre Noble Road. State Route 106 extends along the north
side of the lot. Beyond the property, rural residential development exists. The Hood Canal is
located over 100 feet to the north of the property line. Vegetation on and near the property
consists primarily of firs, cedars,alders,and other trees and shrubbery common to this area of the
Pacific Northwest. An aerial photo of the Project and immediate vicinity is provided on the
following page.
2.2 Topography
The topographic information provided in this section was extrapolated from a public lidar source,
and incorporated observations and field measurements. Where necessary, slope verification
included measuring slope lengths and inclinations with a cloth tape and inclinometer. See the Site
Plan in Appendix A in this report for an illustration of general topography with respect to the
planned development.
Critical descending slopes, with grades exceeding 40% are located on the property. The
maximum critical slope is about 66%with a total vertical relief of approximately 15 feet.
Ascending grades are generally located to the southwest of the planned development. This slope
is relatively minor within 300 feet of the Project,with no apparent slope grades of at least 15%.
2.2.1 Upslope Geomorphology
The upland area of the property is situated on a gentle sloping hillside. Landforms are
primarily of glacial origin. Additional geomorphology that is pertinent to both upslope
and downslope areas are provided in the Subsurface Investigation Section of this report.
23 Surface Drainage
Stormwater runoff originating upslope from the anticipated development appears to primarily
sheet flow, and is expected to be moderate. Runoff originating upslope of the property is mostly
diverted away from the property by upslope development and accommodating topography. Some
scour was observed.
Envirotech Engineering Teny Davis Geotechnical Report
PO Box 984 page 3 123 E Orre Noble Road
Belfair,Washington 98528 Parcel 32232-50-87005&-87006
Ph. 360-275-9374 Union,Mason County,Washington
Fax:360-275-4789 November 25,2013
' 23.1 Upslope Water Bodies
There are no apparent water bodies or wetlands located upslope from the planned
development that would significantly influence the Project.
2.4 Slope and Erosion Observations
The slope grades within the Project signal a potential landslide or erosion hazard area. Some
indicators that suggest past slope movements include:
• Old landslide debris along the backside(western side)of the house
• 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,
• Significant bowing or leaning trees,or,
• Slope sloughing or calving.
Remnants of a shallow translational landslide were observed in the back of the residence.
HOOD CANAL
S
I
E 5T�3ER0��.1N
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4
Proic;ct
Aerial Photo from Mason County Website
Envirotech Engineering Terry Davis Geotechnical Report
PO Box 984 page 4 123 E Orre Noble Road
• Belfair,Washington 98528 Parcel 32232-50-87005&-87006
Ph. 360-275-9374 Union,Mason County,Washington
Fax:360-275-4789 November 25,2013
' 3.0 SUBSURFACE INVESTIGATION
Information on subsurface conditions pertaining to the Project was primarily gathered on October
29`h , 2013 by Michael Staten, geotechnical engineer with Envirotech. Specific information on
field methods, sampling,field testing,general geologic conditions, specific subsurface conditions,
and results from soil testing are presented in this section of the report. Appendix B of this report
includes pertinent information on subsurface conditions for the Project, such as subsoil cross-
section(s), test pit log(s), and water well report(s). Water well reports were utilized to estimate
ground water levels, and if sufficient, were used in identifying subsoil types. Additional well
reports than what is provided in this report may be available from Envirotech upon request.
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 onsite.
Information on subsurface conditions also included reviewing geological maps representing the
general vicinity of the project, and water well reports originating from nearby properties.
Envirotech measured the relative density of the near-surface in-situ soils by gauging the
resistance of hand tools.
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 uncomfortably
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 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:
Qpuop Pre-Fraser Olympic-source glacial and nonglacial deposits—Gravel,sand,silt,clay,
and diamicton, including tills and paleosols;tan to reddish brown or gray;compact;poorly sorted.
Envirotech Engineering Tent'Davis Geotechnical Report
PO Box 984 page 5 123 E Orre Noble Road
Belfair,Washington 98528 Parcel 32232-50-87005&-87006
Ph. 360-275-9374 Union,Mason County,Washington
Fax:360-2754789 November 25,2013
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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.
Fill is apparent on the lot where the planned garage is to be. Within test pit locations, soils within
the upper 5 feet of natural ground were observed to be moist, brown moderately dense silty sand
with gravel(Slbl). Based on nearby soil test pits,well reports, site geology and knowledge of the
general area, soils below the upper 5 feet layer to a depth of about 40 feet below the ground
surface are expected to be very dense hardpan.
Envirotech Engineering Terry Davis Geotechnical Report
PO Box 984 page 6 123 E One Noble Road
Belfair,Washington 98528 Parcel 32232-50-87005&-87006
Ph. 360-275-9374 Union,Mason County,Washington
Fax:360-275-4789 November 25,2013
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 (SCS), the site soils are described as Alderwood gravelly
sandy loam, k, with 15% - 30% slopes, and Cloquallum silty clay loam, Cf, with 5% - 15%
slopes. See the aerial below,and the SCS soil profiles in Appendix B of this report.
Project
Soil Survey From USDA Natural Resources Conservation Service
Envirotech Engineering Terry Davis Geotechnical Report
PO Box 984 page 7 123 E Orre Noble Road
Belfair,Washington 98528 Parcel 32232-50-87005&-87006
Ph. 360-275-9374 Union,Mason County,Washington
Fax: 360-2754789 November 25,2013
. . Unit Legend
Mason County, Washington (WA645)
Map Map Unit Name Acres Percent
Unit in of AOI
Symbol AOI
Aa Alderwood gravelly loam, 5 1.1 0.8%
to 15 percent slopes
Ab Alderwood gravelly sandy 5.2 3.9%
loam, 5 to 15 percent
slopes
Ac Alderwood gravelly sandy 30.4 22.5%
loam, 15 to 30 percent
slopes
Cf Cloquallum silty clay loam, 5 57.0 42.2%
to 15 percent slopes
Eh Everett gravelly sandy 0.1 0.1%
loam, 5 to 15 percent
slopes
Subtotals for Soil Survey Area 93.9 69.5%
Totals for Area of Interest 135.0 100.0%
Soil Map Unit Legend
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. Surface seepage
or perched groundwater at shallow depths was not observed on-site, nor indicated on the
well reports. However, some seasonal groundwater may flow directly above the hardpan
on occasion.
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4.0 ENGINEERING ANALYSES AND CONCLUSIONS
The following sections 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 defining engineering properties of the soil, topography, water
conditions,seismic acceleration and surcharges.
Surface sloughing or other types of surficial slope movements usually do not affect the deep-
seated structural capability of the slope. However, excessive and/or repeated surficial slope
movements, if not repaired, may represent a threat to the structural integrity of the slope. If this
situation does arise, the slope shall be inspected by a geotechnical engineer. Subsequently,
maintenance may be required in order to prevent the possibility of further surficial or deep seated
slope movements that may be damaging to life and property.
According to the Coastal Zone Atlas of Mason County, Washington, the Project is within and
near terrain labeled `Stable' and `Intermediate' regarding potential landslide activity. Stable
slopes are generally not prone to landslides due to small grades and accommodating geology.
Historically, intermediate terrains have no known landslides. A site specific analyses and
conclusions concerning the slopes are presented herein. A Stability Map from the Coastal Zone
Atlas for the general area of this Project may be found below.
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`b '
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Map from Washington State Department of Ecology Website
According to the Department of Natural Resources (DNR) "LHZ — Final A-1 Map —Landslide
Inventory—Mason Watershed, by Sarikhan, et. al., May 2007,"previous landslide activity is not
recorded near the project. Per the Resource Map from DNR, the Project is not within terrain
labeled `highly unstable' or `highly erodible' relating to soils. DNR labeled portions of this
project as medium and high slope instability with relation to slopes. This delineation is primarily
dependent upon slopes and convergence. Secondly, lithology and precipitation are modeled
within this delineation. In summary, this designation is based on mapping without field
observations or knowledge of the specific site geology or soils. A resource map from DNR is
provided below:
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S Puget Sound
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\r� S Puget Sound
th
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D i02 1704064 t 704M3
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Resource Map from Washington State Department of Natural Resources Website
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SOILS — On Resource]lap oniv
Hvdric Sol,
Highly Unstable
Highly Erodible
Highly Unstable&
Highly Erodible
No Data or Gravel
Pits
SLOPE—On Resource\lap only
Medium Slope
Instability
High Slope Instability
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 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: 134 pcf
Angle of internal friction: 34 degrees
Cohesion: 0 psf
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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
conditions are located on the face of the slope. Where the house and garage is located, acceptable
factors of safety were estimated.See the slope stability information in Appendix C for a depiction
of input parameters and example of outputs.
4.2 Erosion
Based on the USCS description of the Project soils, the surface soils are considered moderately
erodible. According to the Resource Map from the Washington State DNR, as provided above,
the Project is not within terrain labeled `highly erodible.' This Project is 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).
Temporary and permanent erosion control measures are required for site development. It is our
opinion that the erosion control plan provided in this report will suffice for this project.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.
Additional erosion control measures than what is initially established may need to be employed if
excessive erosion occurs during construction, or required by the prevailing agency. Complete
erosion control information and specifications may be found in the latest addition of the
"Stonmwater 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 Hood Canal Fault Zone, in which is approximately 1 mile to the northwest of this
Project. This information is based on the USGS Quaternary Fault and Fold Database for the
United States.
Potential landslides due to seismic hazards have been considered, and are addressed in the Slope
Stability Analysis Section provided earlier in this report.
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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
0.46g to 0.59g.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.
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4.3.1 Liquefaction
The potential for liquefaction is believed to be medium to 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
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seismic hazards.No significant saturated sand stratifications are anticipated to be within
the upper 50 feet of the subsoil for this Project
4.4 Retaining Walls and 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.
4.5 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 RECOMN[ENDATIONS
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 Terzaghi 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.
Building foundations should not be established in fill soils. Existing fill soils are
located within the vicinity of the proposed garage. For building on the existing fill,
foundations should extend at least 12 inches below the bottom of the fill. Alternatively,
the fill may be removed and replaced as engineered fill per the Earthwork Construction
Recommendations Section of this report.
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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 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.
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 (Passing U.S. Sieve #10 or greater) that is placed over
undisturbed, competent native subgrade or engineered fill. Native soils found at the
Project site may be suitable for use as material directly beneath concrete slabs if it meets
the aforesaid requirements or screened to meet these requirements. The upper organic
laden native soil should be removed prior to the placement and compaction of the
aforementioned 4-inch coarse,granular material.
The recommendations for interior concrete slabs-on-grade as presented herein are only
relevant for the geotechnical application of this Project. Although beyond the scope of
geotechnical engineering, concrete slabs should also be designed for structural integrity
and environmental reliability. This may include some type of vapor barrier or moisture
control for mitigating excessive moisture in the building.
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
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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.
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
DR ENGINEERED,-**-1
FILL
1
I I UUISTURBED 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
90% of the modified Proctor maximum dry density (ASTM D 1557) and within 3% of
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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 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.
5.2.4 Retaining Wall Backfill
As previously mentioned, significant retaining structures are not anticipated for this
Project. However, if used, native soils may be used as retaining wall backfill for this
Project. Backfill may also consist of engineered fill or borrow materials approved by a
geotechnical engineer. Placement, compaction and extents of retaining wall backfill
should also be specified by a geotechnical engineer or qualified professional.
53 Building and Footing Setbacks
Provided that assumptions relating to construction occur and recommendations are followed as
presented in this report, a building setback from the face of the nearby descending slope
exceeding a 40% grade shall be adhered to. Maintaining the existing setback for the residence
(approximately 15 feet), and a 25 feet garage setback is sufficient. See the Site Plan in Appendix
A for an illustration of the setbacks.
The required setbacks from descending slopes may be reduced, if necessary, and subsequently
would require additional geotechnical studies.
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
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from the structures to an appropriate protected discharge area. Leakage of water pipes, both
drainage and supply lines,shall be prevented at all times.
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 a location near the slope toe as shown on the site plan. Roof and
foundation drains may share a tightline if a backflow preventer is installed within the pipe system
in order to prevent roof water from entering the foundation area. An energy dissipater is required
at the outlet. Recommended outlet locations are delineated on the Site Plan in Appendix A, and
drainage details are provided in Appendix E of this report.
5.5 Vegetation Buffer and Considerations
Vegetation is an excellent measure to minimize surficial slope movements and erosion on slope
faces and exposed surfaces. By removing trees, the root strength is decreased over time, thereby
lowering the `apparent' cohesion of the soil. Transpiration is decreased, which results in
additional groundwater, increased pore water pressure and less cohesion/ friction of the soil
particles. Stormwater runoff also increases, and, fewer plants will create less absorption of the
force from raindrops,thereby creating the potential for erosion hazards.
For this project, we believe that a detailed clearing and grading plan is not warranted, and basic
vegetation management practices should be adhered to.Vegetation shall not be removed from the
face of the critical slope and within 5 feet from the top of the slope. However, any tree deemed
hazardous to life or property shall be removed. If tree removal is necessary,then stumps and roots
shall remain in place, and the underbrush and soil shall remain undisturbed as much as possible.
Any disturbed soil shall be graded and re-compacted in order to restore the terrain similar to
preexisting conditions and drainage patterns.Tree limbing is acceptable if the trees are kept alive.
See the Site Plan in Appendix A of this report for a depiction of the vegetation buffer.
5.6 Temporary and Permanent Erosion Control
4.2.1 Temporary Erosion Control
Erosion control during construction should include minimizing the removal of vegetation
to the least extent possible, and may include stockpiling cleared vegetation, silt fencing,
intercepting swales, berms, straw bales, plastic cover or other standard controls. Silt
fencing is presented in this report as the first choice for temporary erosion control. Any
erosion control should be located down-slope and beyond the limits of construction and
clearing of vegetation where surface water is expected to flow. If the loss of sediments
appears to be greater than expected, or erosion control measures are not functioning as
needed, additional measures must be implemented immediately. See Appendix C for
sketches and general notes regarding selected erosion control measures. The Site Map in
Appendix A depicts the recommended type and locations for erosion control facilities to
be installed.
4.2.2 Permanent Erosion Control
Permanent erosion control is necessary if substantial vegetation has not been established
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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 C. Additional erosion control measures that
should be performed include routine maintenance and replacement, when necessary, of
permanent erosion control,vegetation,drainage structures and/or features.
5.7 Septic Drainfields
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.
By developing the property and following the recommendations provided in this report, the
property owner(s) shall be required to acknowledge in writing the risks inherent in developing in
a geologic hazard area,to accept the responsibility of any adverse effects which may occur to the
subject property or other properties as a result of the development, and to agree to convey the
knowledge of this risk to persons purchasing the site by filing a notice on the property title.
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
PL_AI,4i�.
Michael Staten,P.E.
Geotechnical Engineer
Envirotech Engineering Teary Davis Geotechnical Report
PO Box 984 page 22 123 E Orre Noble Road
Belfair,Washington 98528 Parcel 32232-50-87005&-87006
Ph. 360-275-9374 Union,Mason County,Washington
Fax:360-275-4789 November 25,2013
APPENDIX A
SITE PLAN
HOOD
SCALE I INCH = 30 FEET
CANAL
0 15 30
SOILS; FILL, & LOOSE
TO MEDIUM DENSE SILTY
SAND WITH GRAVEL (SM) TE 106
OVERLYING VERY DENSE R�U 40%+ SLOPE
GLACIAL TILL E STATE A TOE OF
PROPERTY LINE
ROOF DRAIN OUTLETS ON 4'X10' ROCK
PAD AS CLOSE TO SLOPE TOE AS
POSSIBLE. SEE DR VNAGE DETAILS. + SLOPE -- --
Co -____--- _ _- X.... X EXISTING DRAINFIELD
_ X.....XX G SETBACK_ _ BETWEEN HOUSE AND
15' BUILDI - -- - - SLOPE
_5 - BUFFER . - 41
SILT FENCE. - 1 VEGETATION X
SEE DETAILS. X-- X EXIS IN ccuu
X....... HOU r.
X..... SETBACK'
. 25' BUILDING_ ___ �
PROPOSED
SUBSTANTIAL GARAGE
FILL ON LOT q
-87005. SEE TP2
REPORT FOR 56FTt 52FT±
MITIGATION.
PARCEL 32232-50-e 0 -"ARCEL 32232-50-87006
,moo
EXISTING SHARED
DRIVEWAY
VEGETATE ALL DENUDED
AREAS. SEE EROSION
CONTROL DETAILS.
ROCK STABILIZED CONSTRUCTION
ENTRANCE. SEE EROSION CONTROL DETAILS.
E O R R E NOBLE ROAD PROJECT/ OWNER/ LOCATION,
SINGLE FAMILY RESIDENCE
NOTES- GEOTECHNICAL REPORT
1. CONTOURS WERE NOT PREPARED BY A LICENSED LAND SURVEYOR. T. DAVIS
CONTOURS WERE EXTRAPOLATED FROM A PUBLIC LIDAR SOURCE, AND 123 E. ORRE NOBLES
INCORPORATED FIELD MEASUREMENTS AS EXPLAINED IN THE GEOTECHNICAL LEGEND PARCEL 32232-50-87005 R -87006
REPORT.2. BOUNDARIES WERE NOT PREPARED BY A LICENSED SURVEYOR. LOCATIONS MASON COUNTY WASHINGTON
OF SITE FEATURES THAT ARE SHOWN HERE, SUCH AS TOP OF SLOPES, TOE TEMPORARY ENGINEER-
OF SLOOPES, WATER FEATURES, ETC.., WITH RELATION TO THE PROPERTY +++EROSION CONTROL ENVIROTECH ENGINEERING
LINES MUST BE VERIFIED BY THE OWNER. RECOMMENDATIONS IN THE -- SLOPE INDICATOR PO BOX 984
GEOTECHNICAL REPORT PROVIDE SETBACKS, BUFFERS, DEPTHS, ETC_ WITH BELFAIR, WASHINGTON 98528
RELATION TO GEOLOGIC FEATURES, NOT PROPERTY LINES. THESE GEOLOGIC SO- EXISTING CONTOUR 360-275-9374
FEATURES MAY BE LOCATED ON THE SUBJECT PROPERTY OR NEIGHBORING
PROPERTIES. TPI@ TE!LfjL____j SITE PLAN
APPENDIX B
SOIL INFORMATION
VERTICAL AND HORIZONTAL SCALE-
1 INCH - 40 FEET
0
EXISTING HOUSE
MEDIUM DENSE SILTY SAND
WITH GRAVEL (SM)
SR 106
DENSE GLACIAL TILL
SECTION A-A
PROJECT/ OWNER/ LOCATION,
SINGLE FAMILY RESIDENCE
GEOTECHNICAL REPORT
T. DAVIS
PARCEL 32232 50 87006
MASON COUNTY, WASHINGTON
NOTESi
1) MINOR GRADE CHANGES REQUIRED IN ORDER TO ACHIEVE ENGINEER
POSITIVE DRAINAGE. FILL TO BE REMOVED FROM 2ND LOT ENVIROTECH ENGINEERING
PER GEOTECHNICAL REPORT. 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: Terry Davis Geotechnical Report DATE OF LOG: 10/29/2013
PROJECT NO: 13107 LOGGED BY: MCS
CLIENT: Terry Davis EXCAVATOR: N/A
LOCATION: Parcel 32232 50 87006 DRILL RIG: None
Mason County, Washington ELEVATION: N/A
INITIAL DEPTH OF WATER: N/A FINAL DEPTH OF WATER: N/A
SOIL STRATA, STANDARD PENETRATION TEST
DEPTH SAMPLERS USCS DESCRIPTION LL PI CURVE
AND TEST DATA DEPTH N 10 30 50
0 ... ... . . . . .
SM Brown, moist, loose to medium dense
SILTY SAND with GRAVEL. Gravel is
primarily well-graded and subangular.
Sand is mostly medium. Low plasticity.
2
3
4 Light brown, dense
Excavation terminated at approximately
5 4.5 feet
6
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: Terry Davis Geotechnical Report DATE OF LOG: 10/29/2013
PROJECT NO: 13107 LOGGED BY: MCS
CLIENT: Terry Davis EXCAVATOR: N/A
LOCATION: Parcel 32232 50 87006 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 . . I . . . . .. . . I I . . .. . .
FILL Native, un-compacted
1
2
Excavation terminated at approximately
2.5 feet
3
4
5
6
7
8
9
110
No Groundwater Encountered ENVIROTECH ENGINEERING
This information pertains only to this boring and should not be Geotechnical Engineering
interpreted as being indicative of the entire site.
Map Unit Description:Alderwood gravelly sandy loam,15 to 30 percent slopes—
Mason County,Washington
Mason County, Washington
Ac—Alderwood gravelly sandy loam, 15 to 30 percent slopes
Map Unit Setting
Elevation: 50 to 800 feet
Mean annual precipitation: 25 to 60 inches
Mean annual air temperature: 48 to 52 degrees F
Frost-free period. 180 to 220 days
Map Unit Composition
Alderwood and similar soils: 100 percent
Description of Alderwood
Setting
Landform: Drainageways
Parent material: Basal till with a component of volcanic ash
Properties and qualities
Slope: 15 to 30 percent
Depth to restrictive feature: 24 to 32 inches to densic material
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 36 inches
Frequency of flooding: None
Frequency of ponding: None
Available water capacity: Low (about 3.4 inches)
Interpretive groups
Land capability(nonirrigated):4e
Typical profile
0 to 10 inches: Gravelly ashy loam
10 to 28 inches:Very gravelly loam
28 to 60 inches: Gravelly sandy loam
Data Source Information
Soil Survey Area: Mason County, Washington
Survey Area Data: Version 7, Jun 29, 2012
Sn� Natural Resources Web Soil Survey 10/5/2012
Conservation Service National Cooperative Soil Survey Page 1 of 1
HOLT DRILLING, INC.
Resource Protection Well Report
GProject Name0425/?' w r 1 I Date d� �dy
Q- Well Identification # 41t--i
County �ror,
Drilling Method 41, Section 33 T. ow R. 3�✓
a
Driller Street Address /0?�
License # o/ Start Card.. �Q�� �G
Consulting Firm
O AS-BUILT WELL DATA FORMATION DESCRIPTION
Q T T
1 �
s` MONUMENT TYPE:
! CONCRETE SURFACE SEAL 'e4l 'Sal' _
s ft
1
i
O / - deft.
PVC BLANK a "X /�
C% 1 I
I
Q BACKFILL ft.
1
I ,
QX TYPE: zr,, •
I
1 - 1
PVC SCREEN "A
I ..4Jy
SLOT SIZE: �y '
O TYPE:
Z I 1
1 ^ I
ft.
GRAVEL PACK /US �
Q , MATERIAL: ,
1 ,
Q
g
O
LU REMARKS �' z
Q rn
WELL DEPTH
ON
I
Q � 1
i
t � i
,
Signature
VAV039.CDfl
J
APPENDIX C
SLOPE STABILITY
STABLE Slope Stability Analysis System
New User
Project Terry Davis
Datatile: dynamic Bishop
STABLE Version 9.03.00u
Bishop
TITLE
dynamic
UNITS (Metric/Imperial) = I
+»++x+xx++>+>x+x+x>+»»+x+x+x>+x+++xxx>»>+x+x+++»»>++
GEOMETRY DEFINITION
POINTS
NO. X Y
1 0.000 60.000
2 61.000 40.000
3 116.000 20.000
4 122.000 15.000
5 132.000 0.000
6 0.000 55.000
7 61.000 35.000
8 116.000 15.000
9 122.000 10.000
10 132.000 -5.000
11 13.200 55.670
12 18.760 53.850
13 24.320 52.030
14 29.870 50.210
15 35.430 48.380
16 40.990 46.560
17 46.550 44.740
18 52.110 42.920
19 57.660 41.090
20 63.220 39.190
21 68.780 37.170
22 74.340 35.150
23 79.890 33.130
24 85.450 31.110
25 91.010 29.090
26 96.570 27.070
27 102.130 25.D40
28 107.680 23.020
29 113.240 21.000
30 118.800 17.670
LINES
Lo X Hi X SOIL
1 2 1
2 3 1
3 4 1
4 5 1
6 7 2
7 8 2
8 9 2
• 9 10 2
STABLE62002WAssoclates Ltd Printed on: 01/11/13 @ 16:07:56 Page: y
STABLE Slope Stability Analysis System
New User
Project Terry Davis
Datafile: dynamic Bishop
SOILS
SOIL NAME LINETYPE-PEN COHESION FRICTION UNIT WT.
1 Soil 1 CONTINUOUS-BLACK 0.00 34.0 134.000
2 Soil_2 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
165.600
* +
13.200 * * 118.800
+ *
**************+
60.000
X spacing -- no. of cols (max 10)= 10
Y spacing -- no. of rows (max 20)= 20
Grid 1 Circles through point 11
Grid 2 Circles through point 12
Grid 3 Circles through point 13
Grid 4 Circles through point 14
Grid 5 Circles through point 15
Grid 6 Circles through point 16
Grid 7 Circles through point 17
Grid 8 Circles through point 18
Grid 9 Circles through point 19
Grid 10 Circles through point 20
STABLE02002 MZAssociates Ltd Printed on: 01/11113 @ 16:07:56 Page: 2
APPENDIX D
EROSION CONTROL
GE❑TEXTILE FABRIC
WRAP AROUND TRENCH
TO AT LEAST ENTIRE
BOTTOM OF TRENCH
BEFORE PLACING GRAVEL 2'x2'x5' WOOD POST OR
12' DEEP, 8' WIDE TRENCH EQUIVALENT OR BETTER
FILLED WITH 3/4' TO 1 1/2'
WASHED GRAVEL OR VEGETAT N
2.5 FT
DIRECTI❑N OF EXISTING
WATER FLOW GROUND SURFACE
---i777 t---
} 2.5 FT
I
8'
SILT FENCE - CROSS SECTION
N.T.S.
2'x2' WOOD POST (TYP) GE❑TEXTILE FABRIC
OR EQUIVALENT OR BETTER AND WIRE MESH
@ 6 FT MAX. O.C.
Fes---- 6 FT �{ � 0.5 FT
EXISTING I I
GROUND SURFACE
2 T
12' DEEP, 8' WIDE
TRENCH FILLED WITH ' FT
3/4' TO 1 1/2' 2.5 FT
WASHED GRAVEL OR VEGE TI
BOTTOM EXTENTS OF
GE❑TEXTILE FABRIC SILT FENCE - DETAIL
N.T.S.
PR❑VIDE FULL WIDTH
3/4 IN TO 1 1/�I 0 FT
�F INGRESS/EGRESS
CRUSHED GRAVEL I
PLACED AT 6 IN
MINIMUM DEPTH
WELL-DRAINED
S❑ILS
-0.02 IN/MIN FULL LENGTH
R=25 FT MIN
r PROJECT/ OWNER/ LOCATION,
ACCESS ROAD SINGLE FAMILY RESIDENCE
GE❑TECHNICAL REPORT
STABILIZED C❑NSTRUCTION ENTRANCE TERRY DAVIS
N.T.S. PARCEL 32232-50-87006
MASON COUNTY, WASHINGTON
ENGINEERi
ENVIROTECH ENGINEERING
PO BOX 984
BELFAIR, WASHINGTON 98528
360-275-9374
ER❑SION CONTROL P. 1
PERMANENT EROSION CONTROL NOTES:
ENERAL NOTES,
SEEDING FOR RAW SLOPES
1. SHOULD THE TEMPORARY EROSION AND SEDIMENT CONTROL MEASURES SHOWN ON
THESE PLANS PROVE TO BE INADEQUATE DURING CONSTRUCTION, THE CONTRACTOR 1. BEFORE SEEDING, INSTALL NEEDED SURFACE RUNOFF CONTROL
HALL INSTALL ADDITIONAL EROSION AND SEDIMENT CONTROL FACILITIES. MEASURES SUCH AS GRADIENT TERRACES, INTERCEPTOR DIKES,
2. ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE SWALES, LEVEL SPREADERS AND SEDIMENT BASINS.
INSPECTED DAILY AND IMMEDIATELY MAINTAINED, IF NECESSARY. 2. THE SEED BED SHALL BE FIRM WITH FAIRLY FINE SURFACE,
3. 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
EMPORARY EROSION CONTROL NOTES, APPLIED AT THE RATE OF 120 POUNDS PER ACRE.
4. SEED BEDS PLANTED BETWEEN MAY 1 AND OCTOBER 31 WILL
❑R ALL AREAS WHICH HAVE BEEN STRIPPED OF 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 ROOT STRUCTURE.
ERIOD 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 OF YEAR. GRASS SEEDING GEOTEXTILES, JUTE MAT, CLEAR PLASTIC COVERING).
LONE 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 FOR EROSION
RY SEASON (MAY 1 THRU 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 TO
NLY AS MUCH LAND AS CAN RECEIVE APPROPRIATE PROTECTIVE COVER OR BE PROPORTIONS PURITY GERMINATIO
THERWISE STABILIZED, AFTER HAVING BEEN CLEARED OR OTHERWISE DISTURBED NAME BY WEIGHT(%) (7) (7)
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 ❑THERWISE DISTURBED MUST BE APPROPRIATELY STABILIZED ANNUAL RYE (LOLIUM MULTIFLORUM) 40 96 90
HROUGH 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 ❑THERWISE APPROVED BY THE COUNTY, SEEDING, (JAMESTOWN, BANNER, SHADOW, KOKET)
ERTILIZING AND MULCHING OF CLEARED OR OTHERWISE DISTURBED AREAS SHALL BE WHITE DUTCH CLOVER 10 96 90
ERFORMED DURING THE FOLL❑WING PERIODS- MARCH I TO MAY 15, AND AUGUST 15 TO (TRIFOLIUM REPENS)
CTOBER 1. SEEDING AFTER OCTOBER 1 WILL BE DONE WHEN PHYSICAL COMPLETION
F THE PROJECT IS IMMINENT AND THE ENVIROMENTAL CONDITIONS ARE CONDUCIVE MULCHING
❑ SATISFACTORY GROWTH. IN THE EVENT THAT PERANENT STABILIZATION IS NOT
❑SSIBLE, AN ALTERNATIVE METHOD OF GROUND COVER, SUCH AS MULCHING, NETTING, 1. 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. MULCH SHOULD BE APPLIED IN ALL AREAS WITH EXPOSED SLOPES
N THE EVENT THAT CONSTRUCTION ACTIVITIES OR OTHER SITE DEVELOPMENT GREATER THAN 2:1 (HORIZONTAL VERTICAL).
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 OF THE SEASON. ALL
ND SEDIMENT CONTROL FACILITIES IMMEDIATELY AFTER STORM EVENTS, AND AT AREAS REQUIRING MULCH SHALL BE COVERED BY NOVEMBER 1.
EAST ONCE EVERY WEEK. THE OWNER/ CONTRACTOR SHALL BE RESPONSIBLE FOR
HE MAINTENANCE AND REPAIR OF ALL EROSION AN SEDIMENT CONTROL FACILITIES. TOPSOILING
ET SEASON (OCTOBER 1 THRU APRIL 30) -- ON SITES WHERE UNINTERUPTED 1. TOPSOIL SHOULD BE USED FOR THIS PROJECT DUE TO HIGHLY
ONSTRUCTION ACTIVITY IS IN PROGRESS, THE CLEARING OF LAND, INCLUDING THE DENSE EXPOSED SOILS.
REMOVAL OF EXISTING VEGETATION AND OTHER GROUND COVER, SHALL BE LIMITED 2. TOPSOIL SHOULD BE PLACED ON SLOPES NOT EXCEEDING 2�1.
TO AS MUCH LAND AREA AS CAN BE COVERED OR STABILIZED WITHIN 24 HOURS IN 3. STRIPPING AND STOCKPILING ON-SITE SOILS SHALL ONLY BE
HE EVENT A MAJOR STORM IS PREDICTED AND/ OR EROSION AND SEDIMENT PERMITTED IF TOPSOIL IS FRIABLE AND LOAMY (LOAM, SANDY LOAM,
TRANSPORT OFF-SITE IS OBSERVED. SILT LOAM, SANDY CLAY LOAM, CLAY LOAM).
LL CLEARED OR DISTURBED AREAS SHALL RECEIVE APPROPRIATE PROTECTIVE 4. STRIPPING SHALL BE CONFINED TO THE IMMEDIATE CONSTRUCTION
.OVER OR BE ❑THERWISE STABILIZED, SUCH AS MULCHING, NETTING, PLASTIC AREAS. A VA FOUR TO SIX INCH STRIPPING DEPTH IS COMMON, BUT
ING ON THE PARTICULAR SOIL. ALL
MEETING, EROSION BLANKETS, FREE DRAINING MATERIAL, ETC., WITHIN 5 DAYS AFTER DEPTH MAY VA
AVING BEEN CLEARED OR OTHERWISE DISTURBED IF NOT BEING ACTIVELY WORKED, SURFACE RUNOFF CONTROL STRUCTURES SHALL BE IN PLACE BEFORE
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
EING ACTIVELY WORKED REMAINS UNPROTECTED OR HAS NOT BEEN APPR❑PRIATELY
TABILIZED 5 DAYS AFTER HAVING BEEN CLEARED, ALL CONSTRUCTION ACTIVITY ON
HE SITE, EXCEPT FOR APPROVED EROSION AND SEDIMENT CONTROL ACTIVITY, SHALL
MMEDIATELY CEASE UNTIL SUCH A TIME AS AFOREMENTIONED LAND AREA HAS BEEN
PPROPRIATELY PROTECTED OR STABILIZED.
STOCKPILE MANAGEMENT
1. STOCKPILE SHALL BE STABILIZED (WITH PLASTIC COVERING OR OTHER APPROVED DEVICE) DAILY BETWEEN NOVEMBER I AND MARCH
31.
2. IN ANY SEASON, SEDIMENT LEACHING FROM STOCK PILES MUST BE PREVENTED.
3. TOPSOIL SHALL NOT BE PLACED WHILE IN A FROZEN OR MUDDY CONDITION, WHEN THE SUBGRADE IS EXCESSIVELY WET, OR 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
1. MATERIAL SHALL BE 4 INCH TO 8 INCH QUARRY SPALLS (4 TO 6 INCH FOR RESIDENTIAL SINGLE FAMILY LOTS) AND MAY BE
TOP-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 OF
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 OF 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
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 TERRY DAMS
TOGETHER ONLY AT A SUPPORT POST WITH A MINIMUM 6-INCH OVERLAP AND SECURELY FASTENED AT TERCEL 32232-50-87006
BOTH ENDS TO THE POST, MASON COUNTY, WASHINGTON
3. STANDARD FILTER FABRIC SHALL BE FASTENED USING 1' STAPLES OR TIE WIRES (HOG RINGS) @ 4 IN
SPACING,
4. POSTS SHALL BE SPACED AND PLACED AT DEPTHS INDICATED IN THE DETAILS ON THIS SHEET, AND ENGINEER-
DRIVEN SECURELY INTO THE GROUND. ENVIROTECH ENGINEERING
5. WIRE MESH SHALL BE 2'X2'X14 GAUGE OR EQUIVILENT. THE WIRE MESH MAY BE ELIMINATED IF PO BOX 984
EXTRA-STRENGTH FILTER FABRIC (MONOFILAMENT), AND CLOSER POST SPACING IS USED. BELFAIR, WASHINGTON 98528
6. A TRENCH SHALL BE EXCAVATED ACCORDING TO THE DETAILS ON THIS SHEET ALONG THE LINE OF THE 360-275-9374
POSTS AND UPSL❑PE FROM THE SILT FENCE.
7. SILT FENCES SHALL BE LOCATED DOWNSLOPE FROM THE CLEARING LIMITS OF THE PROJECT. ER❑SI❑N CONTROL P. 2
APPENDIX E
DRAINAGE DETAILS
HOUSE
OF DRAIN. SEE
ROOF DOWNSPOUT
CONNECTION
DETAIL SOLID
LID GROUND
SURFACE
4DIA. M
27 MIN
SKID PVC FINE MESH SOLID PIPE
SCREEN PER PLAN
12' CATCH BASIN ANCHOR
(YARD DRAIN) EXPOSED PIPE
PER TIGHTLIN
DETAILS l
O
ROOF DRAINAGE DETAILS dlJ�AI�n�Cy
Oq,
STEEL CLAMPS (TYP)
CORRUGATED TIGHTLINE 10 FT MIN SPACING 1/2 INCH DIAMETER
4-INCH MIN. DIAMETER SECURELY FASTENED TO PIPE
4FT WIDE, 10 FT IN LENGTH QUARRY
SPALL OR APPROVED ENERGY
LEVEL SECTION DISSIPATOR. 8- TO 12-INCH ROCK.
TWO 6-FOOT °o°o°o°o°o°o°o°
ANCHORS (TYP), o°o°o°o°o°o°o° 1 FT MDL
*4 REBAR OR °o°o°o°o°o°o°
EQUIVALENT 3 FT MIN
GEOTEXTILE FABRIC
TIGHTLINE DETAILS
N.T.S.
R013F DOWNSPOUT
GROUND UNGLUED CAP, CUTOUT
SURFACE NEATLY TO ACCEPT
VDOWNSPOUT
=PVC
PROJECT/ OWNER/ LOCATION-
sSOLID SINGLE FAMILY RESIDENT
PIPE A GE❑TECHNICAL REPORT
TERRY DAVIS
4' DIA. PVC 45' PARCEL 32232-50-87005 a -87006
ELBOV MASON COUNTY, WASHINGTON
ENGINEERi
ENVIROTECH ENGINEERING
PO BOX 984
ROOF DOWNSPOUT LMtLCTION C EAbQ T DETAILS BELFAIR, WASHINGTON 98528
N.T.S. 360-275-9374
DRAINAGE DETAILS