HomeMy WebLinkAboutGEO2014-00018 BLD2014-00645 Bulkhead - BLD Engineering / Geo-tech Reports - 11/13/2014 MASON COUNTY
DEPARTMENT OF COMMUNITY DEVELOPMENT
Planning Division
P O Box 279, Shelton, WA 98584
(360)427-9670
Geotechnical ReportReview Acceptance Letter
November 13, 2014
VENTURE PROPERTY MANAGEMENT LLC
P O BOX 556
ALLYN WA 98524
Case No.: GE02014-00018
Parcel No.: 122324091062
Project Description: FOR STABILIZING ERODED BANK, REPAIR FAILED BULKHEAD AND
PROVIDE ACCESS STEPS TO THE BEACH FOR EACH LOT
The Geotechnical Report for VENTURE PROPERTY MANAGEMENT LLC has been received and
reviewed by the Planning Department. The report was prepared by Michael Staten dated
2/17/2014.
Based on the certification provided by the licensed engineer/geologist, the referenced
Geotechnical Report was prepared in general accordance with the requirements in the Mason
County Resource Ordinance, Landslide Hazard Areas 17.01.100.E.5. Mason County considers the
review valid until such time as scope of project, site conditions, and/or regulations change. Should
the scope of work, site conditions, and/or regulations change after the original review, then an
addendum from the original author of the report may be required to address these changes. The
report would only be re-reviewed if a permit for development were submitted after these changes
occur. Mason County does not certify the quality of the work done in this Geotechnical Report.
Please contact me at (360) 427-9670, ext. 365 if you have questions.
Sincerely,
/M�t (a,�-
Allan Borden
Land Use Planner
Mason County Planning Department
Comments:
11/13/2014 Page 1 of 1 GE02014-00018
ED 2M - 00016
Geotechnical Report
for
Venture Property Management Single Family Property
332 E Cronquist Road, Allyn
A Parcel No. 12232-40-91062 and 12232-40-91063
Mason County, Washington
r
February 17, 2014
Project#1413
Prepared For:
Venture Property Management, LLC CLYp
PO Box 556 � oFWAS �9TF
Allyn, Washington 98524
Prepared By:
Envirotech Engineering °A�s FCISTVR-
PO Box 984 SIONAL�N
Belfair, Washington 98528
Phone: 360-275-9374
Fax: 360-275-4789
TABLE OF CONTENTS
1.0 INTRODUCTION........................»........................................................................................................1
1.1 PROJECT INFORMATION.....................................................................................................................1
1.2 PURPOSE OF INVESTIGATION AND SCOPE OF WORK.........................................................................2
2.0 SURFACE CONDITIONS.........».........................................»...»....»................»....................»..........4
2.1 GENERAL OBSERVATIONS..................................................................................................................4
2.2 TOPOGRAPHY......................................................................................................................................4
2.2.1 Upslope Geomorphology.............................................................................................................4
2.3 SURFACE DRAINAGE...........................................................................................................................4
2.3.1 Upslope Water Bodies.................................................................................................................4
2.4 SLOPE AND EROSION OBSERVATIONS................................................................................................5
3.0 SUBSURFACE INVESTIGATION......................................................................................................6
3.1 FIELD METHODS,SAMPLING AND FIELD TESTING............................................................................6
3.2 GENERAL GEOLOGIC CONDITIONS....................................................................................................6
3.3 SPECIFIC SUBSURFACE CONDITIONS..................................................................................................7
3.3.1 Groundwater...............................................................................................................................8
4.0 ENGINEERING ANALYSES AND CONCLUSIONS.......................................................................9
4.1 SLOPE STABILITY................................................................................................................................9
4.1.1 Slope Stability Analysis.............................................................................................................11
4.2 EROSION............................................................................................................................................12
4.2.1 Shoreline Recession..................................................................................................................13
a
4.3 SEISMIC CONSIDERATIONS AND LIQUEFACTION.............................................................................13
4.3.1 Liquefaction..............................................................................................................................13
4.4 LANDSLIDE,EROSION AND SEISMIC HAZARDS CONCLUSIONS.......................................................13
4.5 RETAINING WALLS AND LATERAL EARTH PRESSURES...................................................................14
4.6 ON-SrrE AND OFF-SITE IMPACTS.............................................................."'....................................14
5.0 ENGINEERING RECOMMENDATIONS.......................................................................................15
5.1 BUILDING FOUNDATION RECOMMENDATIONS................................................................................15
S1.1 Bearing Capacity.......................................................................................................................15
5.1.2 Settlement..................................................................................................................................15
5.1.3 Concrete Slabs-on-Grade..........................................................................................................16
5.2 EARTHWORK CONSTRUCTION RECOMMENDATIONS......................................................................16
S2.1 Excavation.................................................................................................................................16
5.2.2 Placement and Compaction of Native Soils and Engineered Fill...........................................17
5.23 Retaining Wall Backfrll............................................................................................................18
5.2.4 Wet Weather Considerations....................................................................................................18
5.3 BUILDING AND FOOTING SETBACKS.................................................................................................18
5.4 SURFACE AND SUBSURFACE DRAINAGE...........................................................................................19
5.5 VEGETATION BUFFER AND CONSIDERATIONS.................................................................................19
5.6 TEMPORARY AND PERMANENT EROSION CONTROL.......................................................................20
5.7 SEPTIC DRAINFIELDS........................................................................................................................20
5.8 STRUCTURAL MITIGATION...............................................................................................................20
6.0 CLOSURE.........................................»..................».............................................................................21
Appendix A-Site Plan
Appendix B-Soil Information(Soil Profile;Soil Logs;Well Reports)
Appendix C-Slope Stability Input&Output
Appendix D-Erosion Control
r `
1.0 INTRODUCTION
Envirotech Engineering (Envirotech) has completed a geotechnical investigation for two
residential parcels located at 332 E Cronquist Road, identified as parcel number 12232-40-91062
and 12232-40-91063, Allyn, 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,
Vance Hoff of Venture Property Management, LLC, in support of the proposed development as
detailed below. The proposed development, as provided herein, and the surrounding area is
identified in this report as the Project.
An initial geotechnical evaluation of the Project was conducted by Envirotech on February 4,
2014. It was determined that ongoing shoreline erosion and slopes in excess of 40% with a
vertical relief of at least 10 feet were present within 300 feet of the 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. Existing development on one lot consists of a single family residence and the other
one is vacant.The existing 5-foot concrete bulkhead runs along the shoreline on both parcels. The
failing portions of the existing seawall is planned to be replaced with a new concrete seawall. A
future 1- or 2-story single family residence, new on-site septic system, and other ancillary
features may be constructed on the vacant lot. 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.
Envirotech Engineering Venture PM,LLC Geotechnical Report
PO Box 984 page 1 PO Box 556
Belfair,Washington 98528 Parcel 12232-40-901062, 12232-40-901063
Ph. 360-275-9374 Allyn,Washington 98524
Fax:360-275-4789 February 17,2014
11 Purpose of Investigation and Scope of Work
The purpose of this geotechnical investigation is to assess geological hazards, and evaluate the
Project in order to provide geotechnical recommendations that should be implemented during
development. The investigation included characterizing the general Project surface and
subsurface conditions, and evaluating the suitability of the soils to support the planned site
activities.
In order to fulfill the purpose of investigation, the geotechnical program completed for the
proposed improvements of the Project include:
• Review project information provided by the Project owner and/ or owner's
representative;
• Conduct a site visit to document the site conditions that may influence the construction
and performance of the proposed improvements of the Project;
• Define general subsurface conditions of the site by observing subsoils within test pits
and/ or cut banks, review geological maps for the general area, research published
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.
Envirotech Engineering Venture PM,LLC Geotechnical Report
PO Box 984 page 2 PO Box 556
Belfair,Washington 98528 Parcel 12232-40-901062, 12232-40-901063
Ph. 360-275-9374 Allyn,Washington 98524
Fax:360-275-4789 February 17,2014
Project
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Vicinity Map from Mason County Website
Envirotech Engineering Venture PM, LLC Geotechnical Report
PO Box 984 page 3 PO Box 556
Belfair, Washington 98528 Parcel 1223240-901062, 1223240-901063
Ph. 360-275-9374 Allyn, Washington 98524
Fax: 360-275-4789 February 17,2014
2.0 SURFACE CONDITIONS
Information pertaining to the existing surface conditions for the Project was gathered on February
3, 2014 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 Cronquist Road, an existing paved roadway. The Project is
currently developed land as previously mentioned.The existing access driveway extends from the
western side of the property, and Case Inlet borders the property to the east. Beyond the property,
rural residential development exists.Vegetation on and near the Project consists primarily of firs,
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 designated on the shoreline bluff. The
maximum critical slope is nearly vertical with a total vertical relief of approximately 25 feet.
Ascending grades are generally located to the southeast of the planned development.These slopes
are 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 hillside of glacial origin.
23 Surface Drainage
Stormwater runoff originating upslope from the development appears to primarily sheet flow
towards the roadway, and channels on the property. Excessive runoff appears to have contributed
to the concrete seawall failure.
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.
Envirotech Engineering Venture PM,LLC Geotechnical Report
PO Box 984 page 4 PO Box 556
Belfair,Washington 98528 Parcel 1223240-901062, 1223240-901063
Ph. 360-275-9374 Allyn,Washington 98524
Fax:360-2754789 February 17,2014
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.
Deep seated slope problems were not observed. The shoreline bank is inherently hazardous,
consists of exposed soils,undermining,and will continue to unravel until stabilized.
E CRONOUIST RD
- c
L
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t
'f E DETROIT DR
Aerial Photo from Mason County Website
Envirotech Engineering Venture PM,LLC Geotechnical Report
PO Box 984 page 5 PO Box 556
Belfair,Washington 98528 Parcel 12232-40-901062, 1223240-901063
Ph. 360-275-9374 Allyn,Washington 98524
Fax:360-2754789 February 17,2014
3.0 SUBSURFACE INVESTIGATION
Information on subsurface conditions pertaining to the Project was primarily gathered on
February 3,2014 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 within
exposed bluffs to depths of up to 6 feet below the natural ground surface. Information on
subsurface conditions also included reviewing geological maps representing the general vicinity
of the project,and water well reports originating from nearby properties.
Soil samples were not obtained from this project. Envirotech measured the relative density of the
near-surface in-situ soils by gauging the resistance of hand tools. Within testing locations, field
testing results generally indicated loose to medium dense soils in the upper 24 inches, and very
dense soils from 24 inches to the depth of terminous.
3.2 General Geologic Conditions
In general, soils at the project are composed of materials from glacial advances. The geologic
conditions as presented in the "Geologic Map of Washington," compiled by J. Eric Schuster,
2002 indicates Quaternary sediments, Qg. Quaternary sediments are generally unconsolidated
deposits, and dominantly deposited from glacial drift, including alluvium deposits. This project is
located within the Puget Lowland. Typically, "lower tertiary sedimentary rocks unconformably
overlie the Crescent Formation."as revealed in the Geologic Map. Initial sedimentary rocks were
formed from shales, sandstones and coal deposits from rivers. During the Quaternary period, the
Puget Lowland was covered by numerous ice sheets,with the most recent being the Fraser glacier
with a peak of approximately 14,000 years ago. Upon the glacial retreat, the landscape was
formed by glacial erosion glacial drift deposits.
The "Geologic Map of the Vaughn 7.5-minute Quadrangles, Pierce and 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:
Envirotech Engineering Venture PM,LLC Geotechnical Report
PO Box 984 page 6 PO Box 556
Belfair,Washington 98528 Parcel 12232-40-901062, 12232-40-901063
Ph. 360-275-9374 Allyn,Washington 98524
Fax:360-2754789 February 17,2014
VIYTII
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N'ashon lodgment till—Unsorted,unstratified mix of clay,silt,sand,gravel,and sparse boulders;
typically supported by a sandy matrix;mostly 3 mY:compact,resembling concrete.
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.
Envirotech Engineering Venture PM,LLC Geotechnical Report
PO Box 984 page 7 PO Box 556
Belfair,Washington 98528 Parcel 12232-40-901062, 12232-40-901063
Ph. 360-275-9374 Allyn, Washington 98524
Fax:360-2754789 February 17,2014
The Project is currently composed of native soils without indications of borrowed fill. Within test
pit locations, soils within the upper 2 feet of natural ground were observed to be moist, brown
silty sand with gravel (SM). Soils below the upper 2 feet layer to a depth of 6 feet below the
ground surface were observed to be mostly grey, low moisture, silty sand with gravel (SM),
locally known as hardpan. The hardpan may extend to depths greater than 50 feet. This is based
on nearby well reports, site geology,and/or knowledge of the general area.
The relative densities of the soil within selected test pits are provided above in Section 3.1.
Expanded and specific subsurface descriptions, other than what is provided in this section, are
provided in the soil logs located in Appendix B of this report.
According to the "Soil Survey of Mason County," by the United States Department of
Agriculture, Soil Conservation Service, the lowland site soils are described as Alderwood
Gravelly Sandy Loam, Ab,with 5% - 15% slopes. The soil designations are depicted in the aerial
photograph below, and descriptions are provided in Appendix B of this report.
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Soil Survey From USDA Natural Resources Conservation Service
3.3.1 Groundwater
From the water well report(s)and knowledge of the general area, permanent groundwater
is at least 50 feet directly below the property at the building pad location. Perched
groundwater at shallow depths was not observed on-site, nor indicated on the well
reports. However, some groundwater is expected to flow directly above the hardpan on
occasion.
Envirotech Engineering Venture PM,LLC Geotechnical Report
PO Box 984 page 8 PO Box 556
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Ph. 360-275-9374 Allyn,Washington 98524
Fax:360-275-4789 February 17,2014
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. 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 Venture PM,LLC Geotechnical Report
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Ph. 360-275-9374 Allyn,Washington 98524
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T
Project
Map from Washington State Department of Ecology Website
According to the Resource Map from the Washington State Department of Natural Resources
(DNR), the Project is not within terrain labeled `highly unstable' relating to soils. DNR labeled
portions of this project as medium slope instability with relation to slopes. This delineation is
primarily dependent upon slopes and convergence. Secondly, lithology and precipitation are
modeled within this delineation. In summary, this designation is based on mapping without field
observations or knowledge of the specific site geology or soils. A Resource Map from the DNR
Forest Practices Application Review System is provided below:
Envirotech Engineering Venture PM,LLC Geotechnical Report
PO Box 984 page 10 PO Box 556
Belfair,Washington 98528 Parcel 12232-40-901062, 12232-40-901063
Ph. 360-275-9374 Allyn,Washington 98524
Fax: 360-2754789 February 17,2014
�Jr `1704664
Project
+7,i4342 +704�,44 S Puget Boundr Y
+70482 0 0 0 0
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Resource Map from Washington State Department of Natural Resources Website
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
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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 2 feet soil depth
Soil unit weight: 134 pcf
Angle of internal friction: 32 degrees
Cohesion: 0 psf
Soils below 2 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.
For this Project,at the location of a future house,minimum factors of safety for static and
dynamic conditions were estimated to be 1.7 and 1.2, respectively. For the bulkhead,
shoreline erosion will not affect stability for an engineered wall. See the slope stability
information in Appendix C for a depiction of input parameters and example of outputs.
4.2 Erosion
Based on the USCS description of the Project soils, the surface soils are considered moderately
erodible. According to the Resource Map from the Washington State DNR, as provided above,
the Project is not within terrain labeled `highly erodible.' This Project is not within an erosion
hazard area as defined by the MCRO. Erosion hazard areas are those with USDA 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
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.
Envirotech Engineering Venture PM,LLC Geotechnical Report
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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
Westem Washington," prepared by the Washington State Department of Ecology Water Quality
Program.
4.2.1 Shoreline Recession
Due to the close proximity of a shoreline,an evaluation of the shoreline recession rate for
this Project was completed. The future shoreline regression will be zero on the subject
property with ordinary care and maintenance of the existing bulkhead.
4.3 Seismic Considerations and Liquefaction
There are no known faults beneath this Project. The nearest Class `A' or Class `B' fault to this
property is the Tacoma Fault Zone, in which is approximately 1 mile to the north 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 Intemational 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.
43.1 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 previous 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 development, results of the aforesaid slope stability analysis, observed surface
conditions, and an evaluation of the shoreline recession rate, it is our opinion that the proposed
development should occur in accordance with this geotechnical report.
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4.5 Retaining Walls and Lateral Earth Pressures
The existing concrete bulkhead is partially failing — primarily due to pore water pressures. We
recommend that replacement of the failed sections are needed for safe conditions. The lateral
earth pressures exerted through the backfill of a retaining wall are dependent upon several factors
including height of retained soil behind the wall, type of soil that is retained, degree of backfill
compaction, slope of backfill, surcharges, hydrostatic pressures, earthquake pressures, and the
direction and distance that the top of the wall moves. A structural or geotechnical professional
should design retaining walls based on specific conditions.
Soil parameters for the structural design of retaining walls may be estimated as 134 pounds per
cubic foot (pcf) and 118 pcf for engineered fill and native soils, respectively. The angle of
internal friction may be estimated as 36 degrees and 32 degrees for engineered fill and native
soils, respectively. These soil parameters are based on soil type and placement conforming to the
Earthwork Construction Recommendations Section in this report.
4.6 On-Site and Off-Site Impacts
From a geotechnical position, it is Envirotech's opinion that the subject property and adjacent
properties to the proposed development should not be significantly impacted if all
recommendations in this report are followed. This opinion is based on the expected site
development, existing topography, existing nearby development, land cover, and adhering to the
recommendations presented in this report. Future development or land disturbing activities on
neighboring properties or properties beyond adjacent parcels that are upslope and/or downslope
from the subject property could cause problems to the subject property. For this reason, future
development or land disturbance near the subject property should be evaluated by a geotechnical
engineer.
Envirotech Engineering Venture PM,LLC Geotechnical Report
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5.0 ENGINEERING RECOMMENDATIONS
The following sections present engineering recommendations for the proposed improvements of
the Project. These recommendations have been made available based on the planned
improvements as outlined in the Introduction Section of this report; general observations
including drainage and topography as recapitulated in the Surface Conditions Section; soil/
geologic conditions that were identified from the geotechnical investigation that is summarized in
the Subsurface Investigation Section; and, Project research, analyses and conclusions as
determined 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
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
f 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.
Residence
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.
Bulkhead
Foundation design and other parameters for the bulkhead should be structurally
engineered using the geotechnical parameters provided in this report.
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
Envirotech Engineering Venture PM,LLC Geotechnical Report
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structure, reduction of pore water pressure, and in some instances, the infiltration of free
moisture. Based on the expected native soil conditions, anticipated development, and
construction abides by the recommendations in this report, the assumed foundation
system may undergo a maximum of 1.0 inch total settlement,and a maximum differential
settlement of 0.75 inch.
5.1.3 Concrete Slabs-on-Grade
Interior slabs, if utilized, should be supported on a minimum of 4 inches of compacted
coarse, granular material (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 for the residence to the extents provided in this Earthwork Construction
Recommendations Section. Bulkhead foundations should be placed on competent, undisturbed
subgrade only. The following recommendations include excavations, subgrade preparation, type
of fill,and placement of fill for building foundations.
5.2.1 Excavation
Excavation is recommended to remove any excessive organic content or other deleterious
material, if present, beneath foundations and to achieve appropriate foundation depth.
Additional sub-excavation will be required for this Project if the soils below the required
foundation depth are loose, saturated, not as described in this report, or otherwise
incompetent due to inappropriate land disturbing, or excessive water trapped within
foundation excavations prior to foundation construction.All soils below the bottom of the
excavation shall be competent, and relatively undisturbed or properly compacted fill. If
these soils are disturbed or deemed incompetent, re-compaction of these soils below the
anticipated footing depth is necessary. Excavations shall be completely dewatered,
compacted, and suitable before placement of additional native soil, engineered fill or
structural concrete.
Envirotech Engineering Venture PM,LLC Geotechnical Report
PO Box 984 page 16 PO Box 556
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511 Placement and Compaction of Native Soils and Engineered Fill
For engineered fill or disturbed native soils that will be utilized as fill material directly
beneath foundations, observation and/ or geotechnical testing is required prior to
foundation construction. The following placement and compaction requirements are
necessary.
For disturbed native soils or engineered fill beneath foundations, limits of compacted or
re-compacted fill shall extend laterally from the bottom edge of the foundation at a rate of
one horizontal foot for each foot of compacted or re-compacted fill depth beneath the
foundation. See the illustration below.
FOOTING
COMPACTED
NATIVE SOILS
OR ENGINEERED I
FILL 1
II UNDISTURBED SUBGRADEI
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.
Envirotech Engineering Venture PM,LLC Geotechnical Report
" PO Box 984 page 17 PO Box 556
Belfair,Washington 98528 Parcel 12232-40-901062, 12232-40-901063
Ph. 360-275-9374 Allyn,Washington 98524
Fax: 360-2754789 February 17,2014
5.23 Retaining Wall Backfill
Bulkhead backfill and drainage shall be separately designed. The following
recommendations are for the residence only. Native soils may be used as retaining wall
backfill for this Project if the total wall height is 4 feet or less and the recommendations
below are followed. Native soils for retaining walls exceeding 4 feet in height must be
approved by the local authority or evaluated by an engineer. Backfill may consist of
engineered fill,as presented in this report, or borrow material approved by a geotechnical
engineer. Compaction of these materials shall be achieved in compacted lifts of about 12
inches. Each lift should be uniformly compacted to at least 85%, and no more than 90%
of the modified Proctor maximum dry density (ASTM D 1557). In addition, heavy
construction equipment should be at a distance of at least %2 the wall height. Over-
compaction and limiting heavy construction equipment should be prevented to minimize
the risk of excess lateral earth pressure on the retaining structure. Envirotech
recommends that retaining wall backfill is compacted with light equipment such as a
hand-held power tamper. If clean, coarse gravel soils are utilized as engineered fill, and
surcharges will not influence the retaining wall, compaction may be achieved by
reasonably densifying granular soils with construction equipment.
Backfill for the retaining wall should extend vertically from the top of the footing to the
proposed ground surface. The backfill should also extend horizontally from the back of
the retaining wall to at least 2 feet.Perforated drain pipe for retaining walls should have a
minimum diameter of 4 inches and direct water to an appropriate infiltration or outfall as
recommended in the Surface and Subsurface Drainage Section of this report. Coarse,
clean gravel (1 inch diameter) is recommended to be placed at least 24 inches around the
drain pipe in order to provide increased drainage capabilities.Non-woven geotextile filter
fabric designed to impede fine particles should be wrapped around the aforementioned
coarse gravel for reducing the potential of silt migration and clogging of the drain pipe.
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.
53 Building and Footing Setbacks
Provided that assumptions relating to construction occur and recommendations are followed as
presented in this report, the factor of safety for slope stability is sufficient for a 25 feet footing
setback from the face of the nearby top of bluff. See the Site Plan in Appendix A for an
illustration of the setbacks.
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5.4 Surface and Subsurface Drainage
Positive drainage should be provided in the final design for all planned residential buildings.
Drainage shall include sloping the ground surface, driveways and sidewalks away from the
Project structures.All constructed surface and subsurface drains should be adequately maintained
during the life of the structure. If drainage problems occur during or after construction, additional
engineered water mitigation will be required immediately. This may include a combination of
swales, berms,drain pipes, infiltration facilities, or outlet protection in order to divert water away
from the structures to an appropriate protected discharge area. Leakage of water pipes, both
drainage and supply lines,shall be prevented at all times.
Residence
From a geotechnical standpoint, roof drains are required for the future residence. Subsurface
water intercepted in the footing perimeter drains, and stormwater collected from roof drains shall
be separately tight-lined to an appropriate infiltration location to the west of the residence or
outlet on the beach. 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.
If subsurface infiltration is not utilized, such as for a beach outlet,an energy dissipater is required
at the outlet. Recommended infiltration locations are delineated on the Site Plan in Appendix A.
Bulkhead
The bulkhead drainage should include drainage collection facilities within the backfill per an
` engineered design,and weep holes to allow water to escape.To mitigate upstream channelization,
upstream water may be collected and conveyed to the front of the bulkhead. Department of
ecology energy dissipation will be required to mitigate beach erosion.
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. Few trees at the edge of the bluff are
danger trees and are planned to be removed. Underbrush should not be removed from the face of
the critical bluff or within a distance of 10 feet beyond the top of the slope, unless bluff
stabilization is employed. Any tree deemed hazardous to life or property should be removed. If
tree removal is necessary, then stumps and roots shall remain in place as much as possible, and
the underbrush and soil shall remain undisturbed. We believe additional plantings on the steep
slope are not feasible for stabilization. If bluff stabilization is considered, see the following
Erosion Control section for details.
Envirotech Engineering Venture PM,LLC Geotechnical Report
PO Box 984 page 19 PO Box 556
Belfair,Washington 98528 Parcel 12232-40-901062, 12232-40-901063
Ph. 360-275-9374 Allyn,Washington 98524
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5.6 Temporary and Permanent Erosion Control
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 for the residence. Best management practices for
bulkhead construction,such as low-tide work,and protecting loose soils from wave action, should
be employed. 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.
Many shoreline bluffs in Mason County are inherently hazardous, and continue to erode and
experience periodic surface sloughing over time. This property is no different. In our opinion,the
property owner may accept and take responsibility of this common phenomenon, or(if allowed
by regulating authorities) stabilize the shoreline bluff. Stabilization may be accomplished by
maintaining the existing bulkhead, and cutting back the full height of the bluff (minus the
bulkhead height)to the angle of repose.The angle of repose is approximately 33 degrees for these
soil conditions. A third alternative is to cut back the upper 3 or 4 feet of the bluff to a 33 degree
or flatter slope. This alternative will create stable conditions in the interim by mitigating shallow
surface sloughing, and allow the bluff to slowly erode over time - primarily by freeze/ thaw
cycles. Upon grading the slope, 4 to 6 inches of topsoil and native seeding should be placed on
the raw slope, and covered with an erosion control blanket properly fastened to propagate the
growth of vegetation.
5.7 Septic Drainfields
The approximate locations of septic drainfields are presented on the Site Plan in Appendix A of
this report. Based on the septic drainfield location with relation to the existing and proposed
topography, the drainfields are not expected to adversely influence critical slopes. This is also
based on compliance with all recommendations in this report.
5.8 Structural Mitigation
With respect to landslide alleviation or slope improvements, structural mitigation is not necessary
for this project. This determination is based on the anticipated improvements of the project,
engineering conclusions,and compliance with all recommendations provided in this report.
Envirotech Engineering Venture PM,LLC Geotechnical Report
PO Box 984 page 20 PO Box 556
Belfair,Washington 98528 Parcel 12232-40-901062, 12232-40-901063
_ Ph. 360-275-9374 Allyn,Washington 98524
Fax:360-275-4789 February 17,2014
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
r 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,
Enviirrot�h Engineering
Michael Staten,P.E.
Geotechnical Engineer
Envirotech Engineering Venture PM,LLC Geotechnical Report
PO Box 984 page 21 PO Box 556
Belfair,Washington 98528 Parcel 12232-40-901062, 12232-40-901063
Ph. 360-275-9374 Allyn,Washington 98524
Fax:360-275-4789 February 17,2014
APPENDIX A
SITE PLAN
SCALE, 1 INCH = 60 FEET
S❑ILS: MEDIUM DENSE SILTY SAND WITH GRAVEL (SM) SEE REPORT FOR 0 15 30 60
OVERLYING VERY DENSE GLACIAL TILL ER❑SION CONTROL
OF BLUFF
25FT BUILDING SETBACK
/320FT± POSSIBLE FUTURE HOUSE
TEMPORARY EROSION xLOFT VEGETATI❑N BUFFER
CONTROL, F NECESSAR UNLESS STABILIZING BLUFF
❑PTI❑NAL R❑ X SEE REPORT,
+1 INFILTRATION AREA,
SEE REPORT v
Co
SEPTIC D AINFIELD X s I
❑PTI❑NAL DRAINAGE
AREA X ;TF i Li OUTLET IN FRONT
z OF SEAWALL. SEE
REPORT
Cy —'_EXISTING WELL w
+1 20' ROAD&UT LITY u
EASEMENT
M APPROXIMATE TOP OF
co
SLOPE EXCEEDING 40%
XISTING DRIVEWAY :::]I m EXISTING RESIDENTAL
STRUCTURE
PROPERTY LINE 320FT± EXISTING 5'-6' CONCRETE
SEAWALL
(SLOPE TOE)
0
e-
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 GE❑TECHNICAL REPORT
GEOTECHNICAL REPORT.
2. CONTOURS WERE NOT PREPARED BY A LICENSED LAND SURVEYOR, VENTURE PROPERTY MANAGEMENT, LLC
CONTOURS WERE EXTRAPOLATED FROM A PUBLIC LIDAR SOURCE, AND P.O. BOX 556
INCORPORATED FIELD MEASUREMENTS AS EXPLAINED IN THE GEOTECHNICAL LEGEND PARCEL 12232-40-901062, 12232-40-901063
REPORT, ALLYN, WASHINGTON 98524
3. BOUNDARIES WERE NOT PREPARED BY A LICENSED SURVEYOR. LOCATIONS �I TEMPORARY ENGINEERi
OF SITE FEATURES THAT ARE SHOWN HERE, SUCH AS TOP OF SLOPES, TOE + 7-EROSION CONTROL ENVIROTECH ENGINEERING
OF SLOOPES, WATER FEATURES, ETC- WITH RELATION TO THE PROPERTY
LINES MUST BE VERIFIED BY THE OWNER, RECOMMENDATIONS IN THE PO BOX 984
GEOTECHNICAL REPORT PROVIDE SETBACKS, BUFFERS, DEPTHS, ETC., WITH --� SLOPE INDICATOR BELFAIR, WASHINGTON 98528
RELATION TO GEOLOGIC FEATURES, NOT PROPERTY LINES. THESE GEOLOGIC -$0-- EXISTING CONTOUR 360-275-9374
FEATURES MAY BE LOCATED ON THE SUBJECT PROPERTY OR NEIGHBORING
PROPERTIES, TPIO TEST PIT SITE PLAN
APPENDIX B
SOIL INFORMATION
VERTICAL AND HORIZONTAL SCALE,
I INCH = 40 FEET
0 10 20 40
FUTURE HOUSE
2 FT SM BROWN W/ GRAVEL
GREY HARDPAN
CONCRETE SEAWALL
(FAILED AREAS TO BE MAINTAINED)
TALLUS AND FILL
BEACH
SECTI❑N A-A
PROJECT/ OWNER/ LOCATION,
SINGLE FAMILY RESIDENCE
GE❑TECHNICAL REPORT
VENTURE PROPERTY MANAGEMENT, LLC
PARCEL12232-40-901062, 12232-40-901063
ALLYN, WASHINGTON 98524
NOTES,
ENGINEER,
1) MINOR GRADE CHANGES REQUIRED IN ORDER TO ACHIEVE ENVIROTECH ENGINEERING
POSITIVE DRAINAGE PO BOX 984
2) THE SOIL PROFILE IS ACCURATE FOR THE DEPTH OF BELFAIR, WASHINGTON 98528
THE OBSERVED TEST PITS AT THE SPECIFIED LOCATIONS. 360-275-9374
LOWER DEPTHS ARE BASED ON SITE GEOLOGY,
WELL LOG(S), AND/OR EXPERIENCE IN THE GENERAL AREA. S❑IL PROFILE
TEST PIT LOG
TEST PIT NUMBER TP-1
PROJECT: Venture PM Geotechnical Report DATE OF LOG: 02/03/2014
PROJECT NO: 1413 LOGGED BY: MCS
CLIENT: Venture Property Management, LLC EXCAVATOR: N/A
LOCATION: Parcel 12232-40-90062 DRILL RIG: None
12232-40-90063 ELEVATION: N/A
Mason County, Washington
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.
1 Sand is mostly medium. Low plasticity.
2
Grey Hardpan, very dense
3
4
5
6 Excavation terminated at approximately
6.0 feet
7
8
9
10
No Groundwater Encountered ENVIROTECH ENGINEERING
This information pertains only to this boring and should not be Geotech nical Engineering
interpreted as being indicitive of the entire site.
APPENDIX C
SLOPE STABILITY
STABLE Slope Stability Analysis System
New User
Project Venture
Datafile : dynamic Bishop
STABLE Version 9.03.00u
Bishop
TITLE
dynamic
UNITS (Metric/Imperial) = I
GEOMETRY DEFINITION
POINTS
NO. X Y
1 0.000 0.000
2 50.000 0.000
3 50.000 -4.000
4 0.000 -2.000
5 55.000 -25.000
6 100.000 -30.000
• 7 10.000 0.000
8 14.210 0.000
9 18.420 0.000
10 22.630 0.000
11 26.840 0.000
12 31.050 0.000
13 35.260 0.000
14 39.470 0.000
15 43.680 0.000
16 47.890 0.000
17 52.110 -12.840
18 56.320 -25.150
19 60.530 -25.610
20 64.740 -26.080
21 68.950 -26.550
22 73.160 -27.020
23 77.370 -27.490
24 81.580 -27.950
25 85.790 -28.420
26 90.000 -28.890
LINES
Lo X Hi X SOIL
1 2 1
2 3 1
4 3 2
3 5 2
5 6 2
SOILS
SOIL NAME LINETYPE-PEN COHESION FRICTION UNIT WT.
STABLE Slope Stability Analysis System
New User
Project Venture
Datafile: dynamic Bishop
2 till 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
80.000
***************
* *
10.000 * * 90.000
* *
***************
0.000
X spacing -- no. of cols (max 10)= 10
Y spacing -- no. of rows (max 20)= 20
Grid 1 Circles through point 7
Grid 2 Circles through point 8
Grid 3 Circles through point 9
Grid 4 Circles through point 10
Grid 5 Circles through point 11
Grid 6 Circles through point 12
° Grid 7 Circles through point 13
Grid 8 Circles through point 14
Grid 9 Circles through point 15
Grid 10 Circles through point 16
Grid 11 Circles through point 17
Grid 12 Circles through point 18
1 _ 00
1 . 10
1 . 20
1 . 30
1 _ 40
1 _ 50
1 . 60
1 _ 70
1 . 80
. 90
2 X(O 0
0 993
P r o j e c t _ Ve n t u r e
Datafile _ dynamic
Analysis _ Bishop
9 TAHLE,2 0 0 2 MZ Am m o c L a t c a Ltd
f �
1 . 00
1 . 10
1 . 20
1 . 30
1 . 40
1 . 50
1 . 60
1 . 70
1 . 80
. 90
2 . 00
1 224
Proj ect _ N7 nture
Datafile static
Analysis Bishop
9TASLffi�2002 MZ Aewociates Ltd
APPENDIX D
EROSION CONTROL
GEOTEXTILE FABRIC GEOTEXTILE FABRIC
BET
_ WRAP AROUND TRENCH 2'x2' WOOD POST AND WIRE MESH
TO AT LEAST ENTIRE OR EQUIVALENT OR BETTER
BOTTOM OF TRENCH 2 6 FT MAX. O.C.
BEFORE PLACING GRAVELD.5 FT
2'x2'x5' WOOD POST OR ��— 6 FT
EQUIVALENT OR BETTER EXISTING
• 12' DEEP, 8' WIDE TRENCH /// GROUND SURFACE
FILLED WITH 3/4' TO 1 1/2'11 2 T
WASHED GRAVEL or VEGETATIN
2.5I FT 12' DEEP, 8' WIDE
DIRECTIOV OF I T
WATER FLOW EXISTING TRENCH FILLED WITH
12' GROUND SURFACE 3/4' TO 1 1/2' 2.5 FT
2.5 FT WASHED GRAVEL OR
VEGETATION
�8 f_ BOTTOM EXTENTS OF
GEOTEXTILE FABRIC SILT FENCE - DETAIL
SILT FENCE - CROSS SECTION N.T.S.
N.T.S. HAY OR STRAW MATTING
ENERAL NOTES: 1, STRAW SHALL BE AIR DRIED, AND FREE FROM WEED SEEDS AND
COARSE MATERIAL.
SHOULD THE TEMPORARY EROSION AND SEDIMENT CONTROL MEASURES SHOWN ON 2, APPLY AT APPROXIMATELY 75 TO 100 POUNDS PER 1000 SQUARE
HESE PLANS PROVE TO BE INADEQUATE DURING CONSTRUCTION, THE CONTRACTOR FEET OF GROUND.
HALL INSTALL ADDITIONAL EROSION AND SEDIMENT CONTROL FACILITIES. 3. MINIMUM THICKNESS SHALL BE 2 INCHES.
1. ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE 4. HAY OR STRAW IS SUBJECT TO BLOWING. KEEP MOIST OR TIED
INSPECTED DAILY AND IMMEDIATELY MAINTAINED, IF NECESSARY, DOWN.
. ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE LEFT IN
LACE UNTIL THE UPSLOPE AREAS HAVE BEEN PERMANENTLY STABILIZED. PERMANENT EROSION CONTROL NOTES:
TEMPORARY EROSION CONTROL NOTES: SEEDING FOR RAW SLOPES
❑R ALL AREAS WHICH HAVE BEEN STRIPPED OF VEGETATION OR EXPERIENCED LAND 1. BEFORE SEEDING, INSTALL NEEDED SURFACE RUNOFF CONTROL
ISTURBING ACTIVITIES, AND WHERE NO FURTHER WORK IS ANTICIPATED FOR A MEASURES SUCH AS GRADIENT TERRACES, INTERCEPTOR DIKES,
ERIOD EXCEEDING THE LISTED CRITERIA BELOW, ALL DISTURBED AREAS MUST BE SWALES, LEVEL SPREADERS AND SEDIMENT BASINS.
MMEDIATELY STABILIZED WITH MULCHING, GRASS PLANTING OR OTHER APPROVED 2. THE SEED BED SHALL BE FIRM WITH FAIRLY FINE SURFACE,
ROSION CONTROL TREATMENT APPLICABLE TO THE TIME OF YEAR. GRASS SEEDING FOLLOWING SURFACE ROUGHENING. PERFORM ALL OPERATIONS ACCROS
%LONE WILL ONLY BE ACCEPTABLE DURING THE MONTHS OF APRIL THROUGH OR PERPENDICULAR TO THE SLOPE.
EPTEMBER. HOWEVER, SEEDING MAY PROCEED WHENEVER IT IS IN THE INTEREST OF 3. SEEDING RECOMMENDATIONS, AS SHOWN BELOW, AND SHOULD BE
HE OWNER/CONTRACTOR, BUT MUST ALSO BE AUGMENTED WITH MULCHING, NETTING APPLIED AT THE RATE OF 120 POUNDS PER ACRE.
R OTHER APPROVED TREATMENT. 4. SEED BEDS PLANTED BETWEEN MAY 1 AND ❑CTOBER 31 WILL
REQUIRE IRRIGATION AND OTHER MAINTENANCE AS NECESSARY TO
RY SEASON (MAY 1 THRU SEPTEMBER 30) -- THE CLEARING OF LAND, INCLUDING THE FOSTER AND PROTECT THE ROOT STRUCTURE,
EMOVAL OF EXISTING VEGETATION OR OTHER GROUND COVER, MUST BE LIMITED TO 5. SEED BEDS PLANTED BETWEEN NOVEMBER 1 AND APRIL 30,
NLY AS MUCH LAND AS CAN RECEIVE APPROPRIATE PROTECTIVE COVER OR BE ARMORING OF THE SEED BED WILL BE NECESSARY, (e.g.,
THERWISE STABILIZED, AFTER HAVING BEEN CLEARED OR OTHERWISE DISTURBED , GEOTEXTILES, JUTE MAT, CLEAR PLASTIC COVERING).
Y NO LATER THAN SEPTEMBER 30 OF A GIVEN YEAR. UNLESS IMMEDIATE 6. FERTILIZERS ARE TO BE USED ACCORDING TO SUPPLIERS'
TABILIZATION IS SPECIFIED IN THE EROSION AND SEDIMENT CONTROL PLAN, ALL RECOMMENDATIONS. AMOUNTS SHOULD BE MINIMIZED, ESPECIALLY
REAS CLEARED OR OTHERWISE DISTURBED MUST BE APPROPRIATELY STABILIZED ADJACENT TO WATER BODIES AND WETLANDS,
HROUGH THE USE OF MULCHING, NETTING, PLASTIC SHEETING, EROSION BLANKETS,
REE DRAINING MATERIAL, ETC., BY SEPTEMBER 30 OR SOONER PER THE APPROVED USE THE FOLLOWING RECOMMENDED SEED MIXTURE FOR EROSION
LAN OF ACTION. UNLESS OTHERWISE APPROVED BY THE COUNTY, SEEDING, CONTROL, OR A COUNTY APPROVED ALTERNATE SEED MIXTURE.
ERTILIZING AND MULCHING OF CLEARED OR OTHERWISE DISTURBED AREAS SHALL BE
ERFORMED DURING THE FOLLOWING PERIODS: MARCH 1 TO MAY 15, AND AUGUST 15 TO PROPORTIONS PURITY GERMINATI❑
CTOBER 1. SEEDING AFTER ❑CTOBER 1 WILL BE DONE WHEN PHYSICAL COMPLETION NAME BY WEIGHT(%) (%) (7)
F THE PROJECT IS IMMINENT AND THE ENVIROMENTAL CONDITIONS ARE CONDUCIVE
❑ SATISFACTORY GROWTH. IN THE EVENT THAT PERANENT STABILIZATION IS NOT REDTOP (AGROSTIS ALBA) 10 92 90
❑SSIBLE, AN ALTERNATIVE METHOD OF GROUND COVER, SUCH AS MULCHING, NETTING, ANNUAL RYE (LOLIUM MULTIFLORUM) 40 98 90
LASTIC SHEETING, EROSION BLANKETS, ETC., MUST BE INSTALLED BY N❑ LATER THAN CHEWING FESUE 40 97 80
EPTEMBER 30. (FESTUCA RUBRA COMMUTATA)
(JAMESTOWN, BANNER, SHADOW, KOKET)
N THE EVENT THAT CONSTRUCTION ACTIVITIES OR OTHER SITE DEVELOPMENT WHITE DUTCH CLOVER 10 96 90
CTIVITIES ARE DISCONTINUED FOR AT LEAST 4 CONSECUTIVE DAYS, THE (TRIFOLIUM REPENS)
�WNER/CONTRACTOR SHALL BE RESPONSIBLE FOR THE INSPECTION OF ALL EROSION
ND SEDIMENT CONTROL FACILITIES IMMEDIATELY AFTER STORM EVENTS, AND AT MULCHING
EAST ONCE EVERY WEEK. THE OWNER/ CONTRACTOR SHALL BE RESPONSIBLE FOR
HE MAINTENANCE AND REPAIR OF ALL EROSION AN SEDIMENT CONTROL FACILITIES. 1. MATERIALS USED FOR MULCHING ARE RECOMMENDED TO BE WOOD
FIBER CELLULOSE, AND SHOULD BE APPLIED AT A RATE OF 1000
ET SEASON (OCTOBER 1 THRU APRIL 30) -- ON SITES WHERE UNINTERUPTED POUNDS PER ACRE.
ONSTRUCTION ACTIVITY IS IN PROGRESS, THE CLEARING OF LAND, INCLUDING THE 2. MULCH SHOULD BE APPLIED IN ALL AREAS WITH EXPOSED SLOPES
REMOVAL OF EXISTING VEGETATION AND OTHER GROUND COVER, SHALL BE LIMITED GREATER THAN 2-1 (HORIZONTAL-VERTICAL).
TO AS MUCH LAND AREA AS CAN BE COVERED OR STABILIZED WITHIN 24 HOURS IN 3. MULCHING SHOULD BE USED IMMEDIATELY AFTER SEEDING OR IN
HE EVENT A MAJOR STORM IS PREDICTED AND/ OR EROSION AND SEDIMENT AREAS WHICH CANNOT BE SEEDED BECAUSE OF THE SEASON. ALL
TRANSPORT OFF-SITE IS OBSERVED. AREAS REQUIRING MULCH SHALL BE COVERED BY NOVEMBER 1.
LL CLEARED OR DISTURBED AREAS SHALL RECEIVE APPROPRIATE PROTECTIVE
OVER OR BE OTHERWISE STABILIZED, SUCH AS MULCHING, NETTING, PLASTIC
HEETING, EROSION BLANKETS, FREE DRAINING MATERIAL, ETC., WITHIN 5 DAYS AFTER
AVING BEEN CLEARED OR OTHERWISE DISTURBED IF NOT BEING ACTIVELY WORKED,
ILT FENCING, SEDIMENT TRAPS, SEDIMENT PONDS, ETC., WILL NOT BE VIEWED AS
DEQUATE COVER IN AND OF THEMSELVES. IN THE EVENT THAT ANY LAND AREA NOT
EING ACTIVELY WORKED REMAINS UNPROTECTED OR HAS NOT BEEN APPROPRIATELY
TABILIZED 5 DAYS AFTER HAVING BEEN CLEARED, ALL CONSTRUCTION ACTIVITY ON
HE SITE, EXCEPT FOR APPROVED EROSION AND SEDIMENT CONTROL ACTIVITY, SHALL
ffT
EDIATELY CEASE UNTIL SUCH A TIME AS AFOREMENTIONED LAND AREA HAS BEEN
ROPRIATELY PROTECTED ❑R STABILIZED.
FENCE
PROJECT/ OWNER/ LOCATION
. GEOTEXTILE FILTER FABRIC TYPE SHALL BE PER SPECIFIED IN THE 'STORMWATER MANAGEMENT MANUAL SINGLE FAMILY PROPERTY
OR THE PUGET SOUND BASIN,' OR APPLICABLE COUNTY STANDARDS
GEOTEXTILE FILTER FABRIC SHALL BE PURCHASED IN A CONTINUOUS ROLL CUT TO THE LENGTH OF GE❑TECHNICAL REPORT
ACH BARRIER TO AVOID USE OF JOINTS. IF JOINTS ARE NECESSARY, FILTER FABRIC SHALL BE SPLICED VENTURE PM, LLC
OGETHER ONLY AT A SUPPORT POST WITH A MINIMUM 6-INCH OVERLAP AND SECURELY FASTENED AT 332 CRONQUIST ROAD
OTH ENDS TO THE POST. MASON COUNTY, WASHINGTON
3. STANDARD FILTER FABRIC SHALL BE FASTENED USING I' STAPLES OR TIE WIRES (HOG RINGS) 2 4 IN
PACING.
` , POSTS SHALL BE SPACED AND PLACED AT DEPTHS INDICATED IN THE DETAILS ON THIS SHEET, AND ENGINEER
RIVEN SECURELY INTO THE GROUND. ENVIROTECH ENGINEERING
. WIRE MESH SHALL BE 2'X2'X14 GAUGE OR EQUIVALENT, THE WIRE MESH MAY BE ELIMINATED IF P❑ 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.
7. SILT FENCES SHALL BE LOCATED DOWNSLOPE FROM THE CLEARING LIMITS OF THE PROJECT. EROSION CONTROL
a TOPSOILING
' 1. TOPSOIL SHOULD BE USED FOR THIS PROJECT DUE TO HIGHLY DENSE EXPOSED
SOILS.
2. TOPSOIL SHOULD BE PLACED ON SLOPES NOT EXCEEDING 2-1.
3. STRIPPING AND STOCKPILING ON-SITE SOILS SHALL ONLY BE PERMITTED IF
TOPSOIL IS FRIABLE AND LOAMY (LOAM, SANDY LOAM,SILT LOAM, SANDY CLAY LOAN,
CLAY LOAM).
4. STRIPPING SHALL BE CONFINED TO THE IMMEDIATE CONSTRUCTION AREAS. A FOUR
TO SIX INCH STRIPPING DEPTH IS COMMON, BUT DEPTH MAY VARY DEPENDING ON
THE PARTICULAR SOIL. ALL SURFACE RUNOFF CONTROL STRUCTURES SHALL BE IN
PLACE BEFORE STRIPPING.
SEEDING FOR RAW SLOPES
1. BEFORE SEEDING, INSTALL NEEDED SURFACE RUNOFF CONTROL MEASURES SUCH AS
GRADIENT TERRACES, INTERCEPTOR DIKES, STALES, LEVEL SPREADERS AND SEDIMENT BASINS.
2. THE SEED BED SHALL BE FIRM WITH FAIRLY FINE SURFACE, FOLLOWING SURFACE
ROUGHENING. PERFORM ALL OPERATIONS ACCROSS OR PERPENDICULAR TO THE SLOPE.
3. SEEDING MIXTURE SHALL BE AS SHOWN BELOW, AND SHALL BE APPLIED AT THE RATE OF
120 POUNDS PER ACRE.
4. SEED BEDS PLANTED BETWEEN MAY 1 AND OCTOBER 31 WILL REQUIRE IRRIGATION AND
OTHER MAINTENANCE AS NECESSARY TO FOSTER AND PROTECT THE ROOT STRUCTURE.
5. SEED BEDS PLANTED BETWEEN NOVEMBER I AND APRIL 30, ARMORING OF THE SEED BED
WILL BE NECESSARY, (e.g., GEOTEXTILES, JUTE MAT, CLEAR PLASTIC COVERING).
6. FERTILIZERS ARE TO BE USED ACCORDING TO SUPPLIERS' RECOMMENDATIONS. AMOUNTS
SHOULD BE MINIMIZED, ESPECIALLY ADJACENT TO WATER BODIES AND WETLANDS.
USE THE FOLLOWING RECOMMENDED SEED MIXTURE FOR EROSION CONTROL, OR A MASON
COUNTY APPROVED ALTERNATE SEED MIXTURE.
PROPORTIONS PURITY GERMINATION
NAME BY WEIGHT (7) (%) (7)
REDTOP (AGROSTIS ALBA) 10 92 90
ANNUAL RYE (LOLIUM MULTIFLORUM) 40 98 90
CHEWING FESUE 40 97 80
(FESTUCA RUBRA COMMUTATA)
(JAMESTOWN, BANNER, SHADOW, KOKET)
WHITE DUTCH CLOVER 10 96 90
(TRIFOLIUM REPENS)
NETS AND MATS
1. ON SHALLOW SLOPE, NETTING MAY BE APPLIED ACROSS THE SLOPE.
(SLOPES UP TO SQ).
2. ON STEEP SLOPES, APPLY STRIPS OF NETTING PARALLEL TO THE
DIRECTION OF FLOW AND ANCHOR SECURELY. (SLOPES GREATER THAN 1-1)
3. WHERE THERE IS A BERM AT THE TOP OF THE SLOPE, BRING THE
NETTING OVER THE BERM AND ANCHOR IT BEHIND THE BERM.
4. BRING THE NETTING DOWN TO A LEVEL AREA BEFORE TERMINATING THE
INSTALLATION. TURN THE END UNDER 6' AND STAPLE AT 12' INTERVALS.
5. IN DITCHES, APPLY NETTING PARALLEL TO THE DIRECTION OF FLOW. USE
CHECK SLOTS EVERY 15 FEET. DO NOT JOIN STRIPS IN THE CENTER OF
THE DITCH.
6. NETS AND MATS USED ALONE, WITHOUT MULCH, DO NOT RETAIN SOIL
TEMPPERATURE.
7. IT IS CRITICAL DURING INSTALLATION TO OBTAIN FIRM, CONTINUOUS
CONTACT BETWEEN THE NET/MAT MATERIAL AND THE SOIL. WITHOUT
SUCH CONTACT, THE MATERIAL IS USELESS AND EROSION OCCURS.
8. WHEN ANCHORING MATERIAL, IT IS IMPORTANT TO USE AN ADEQUATE
NUMBER OF STAPLES AND TO ROLL THE MATERIAL AFTER LAYING IT TO
ENSURE THAT THE SOIL IS PROTECTED. NETTING SHOULD BE SECURELY
ANCHORED TO THE SOIL WITH NO. 11 GAUGE WIRE STAPLES AT LEAST
6-INCHES LONG, WITH AN OVERLAP OF 3-INCHES.
9. SITE PREPARATION IS THE SAME AS FOR TEMPORARY SEEDING.
10. WHERE SOIL IS HIGHLY ERODIBLE, NETS SHOULD ONLY BE USED IN
CONJUNCTION WITH ORGANIC MULCH.
11. JUTE NETS SHOULD BE HEAVY, UNIFORM CLOTH WOVEN OF SINGLE JUTE
YARN, WHICH, IF 36-TO 48-INCHES WIDE, SHALL WEIGH AN AVERAGE OF
1.2 LBS. PER LINEAR YARD. JUTE MATTING MUST BE APPLIED SO THAT IT
IS IN COMPLETE CONTACT WITH THE SOIL, OTHERWISE EROSION WILL
OCCUR BENEATH IT.
12. WOOD FIBER CELLULOSE BLANKETS ARE CONSIDERED PROTECTIVE
MULCHES AND MAY BE USED ALONE ON ERODIBLE SOILS AND DURING ALL
TIMES OF THE YEAR.
SURFACE ROUGHENING
1. SURFACE ROUGHENING IS INTENDED TO AID IN THE ESTABLISHMENT OF
VEGETATIVE COVER, WHICH IN TURN IS INTENDED TO PROTECT THE
FACE OF THE SLOPE FROM RAINFALL IMPACT AND SEEDFLOW, BIND THE
SURFACE OF THE SLOPE TO RETARD EROSION, AND REDUCE THE
VELOCITY OF SURFACE RUNOFF, SURFACE ROUGHENING IS NOT INTENDED
TO ACCOMPLISH ANY OF THE ABOVE BY ITSELF, AND DEFINITELY
SHOULD NOT BE USED TO DIRECTLY REDUCE THE VELOCITY OF SURFACE
RUNOFF.
2. GRADED SLOPES STEEPER THAN 34 BUT LESS THAN 24 SHOULD BE
ROUGHENED BEFORE SEEDING, THIS CAN BE ACCOMPLISHED IN A VARIETY
OF WAYS, INCLUDING 'TRACK-WALKING', OR DRIVING A CRAWLER PROJECT/ OWNER/ LOCATION:
TRACTOR UP AND DOWN THE SLOPE, LEAVING A PATTERN OF CLEAT
IMPRINTS PARALLELTO SLOPE CONTOURS. THE TREAD IMPRINTS ARE SINGLE FAMILY PROPERTY
IDEAL PLACES TO TRAP SEEDS AND ENCOURAGE PLANTS TO BECOME
ESTABLISHED. GEOTECHNICAL REPORT
3. GRADED AREAS STEEPER THAN 2-1 SHOULD BE STAIR-STEPPED WITH
BENCHES THE STAIR-STEPPING WILL HELP VEGETATION BECOME VENTURE PM, LLC
ESTABLISHED AND ALSO TRAP SOIL ERODED FROM THE SLOPES ABOVE. 332 CRUNQUIST ROAD
MASON COUNTY, WASHINGTON
a ENGINEER;
ENVIROTECH ENGINEERING
PO BOX 984
EROSION CONTROL FOR BLUFF CUTS BELFAIR, WASHINGTON 98528
360-275-9374
T ER❑SION CONTROL
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.
i
Applicant/Owner `�2✓�Twri �I�o� � �ll Parceel# 'Z Z 3Z-y D-9l,�E 2 1223 - ��r963
Site Address ,3G- G C�gnyu+°3T ��
(1) (a)A discussion of general geologic conditions in the vicinity of the proposed development,
Located on page(s) 6
(b) A discussion of spe�fic soil types
Located on page(s)
(c) A discussion of ground water conditions
Located on page(s) YJ
(d) A discussion of the upslope geomorphology
Located on page(s)
(e) A discussion of the location of upland waterbodies and wetlands
Located on page(s) L-
(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)
(2) A site plan which identifies the important development and geologic features.
Located on Map(s) S� P/a Y'�
(3) Locations and logs of exploratory holes or probes.
Located on Map(s) CJe_Ajr-�n i So
(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) �a,-k P,to n
(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.
I Located on Map(s) ��e Pr,�J_
(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) /I
(7) (a)Appropriate restrictions on placement of drainage features
Located on page(s) 1
(b) Appropriate restrictions on placement of septic drain fields
Located on page(s) 20
(c) Appropriate restrictions on placement of compacted fills and footings
Located on page(s) 1 S 17
Page 1 of 2 Form Effective June 2008
Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report.
(d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other
slopes on the property.
Located on page(s) /Y
(e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of
other slopes on the property.
Located on page(s) La
(8) Recommendations for the preparation of a detailed clearing and grading plan which specifically
identifies vegetation to be removed, a schedule for vegetation removal and replanting, and the
method of vegetation removal.
Located on page(s) /9
(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) Z
(10) An analysis of both on-site and off-site impacts of the proposed development.
Located on page(s) /9-
(11) Specifications of final development conditions such as, vegetative management, drainage,
erosion control, and buffer widths.
Located on page(s)
(12) Recommendations for the preparation of structural mitigation or details of other proposed
mitigation.
Located on page(s) Lr'
(13) A site map drawn to scale showing the property boundaries, scale, north arrow, and the location
and nature of existing and pro osed development on the site.
Located on Map(s) 4 .,e /Ov\
C yck, C 44'1 hereby certify under penalty of
perjury that I am a civil engineer licensed in the State of Washington with specialized knowledge of
geotechnical/geological engineering or a geologist or engineering geologist licensed in the State of
Washington with special knowledge of the local conditions. I also certify that the Geotechnic��/al
Report, dated Fri i7i 'ZOI4, and entitled �����T�rc. / 'r`p�!e, t� ��vlcAceenzol
G,Y1 CrlC {ufvt Ior" �+' meets all the requirements of the Mason
Co ^Resource O dinance, 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)
PTV CLYDE ST
%N"As I.X
?� 43045
GISTV
Page 2 of 2 Form Effective June 2008
Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report.
1
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: � / ��"1✓lN Fnr�l
Permit#,6 y(1 14 Parcel# �ZZ� ` "c0V-Z��"�
Date(s) of the Document(s) reviewed:
(1) (a)A discussion of general geologic conditions in the vicinity of the proposed development,
OK? Comment:
(b) A discussion of specific soil types
4OK? Comment:
(c) A discussion of ground water conditions
OK? Comment:
(d) A discussion of the upslope geomorphology
OK? Comment:
(e) A discussion of the location of upland waterbodies and wetlands
OK? Comment:
(f) A discussion of history of landslide activity in the activity in the vicinity, as available in the
referenced maps and records
OK? Comment:
(2) A site plar�which identifies the important development and geologic features.
OK? �i// Comment:
(3) Locations/and logs of exploratory holes or probes.
OK? V Comment:
(4) The area of the proposed development, the boundaries of the hazard, and associated buffers and
setbacks all be delineated (top, both sides, and toe)on a geologic map of the site.
OK? V Comment:
(5) A minimum of one cross section at a scale which adequately depicts the subsurface profile, and
which incor orates the details f proposed grade changes.
OK?Comment: ���
(6) A description and results of s ope stability nalyses 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 s ty factor is 1.1. and they uasi-static analysis coeffients should be a value of 0.15.
OK? Comment: ((
(7) (a)Approp ate restrictions o placement of drainage features
OK? Comment:
(b) Appro late restrictions on placement of septic drain fields
OK? omment:
(c) AppVroiate restrictions on placement of compacted fills and footings
OK? omment:
(d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other
slopes on the property.
Page 1 of 2 Form Effective June 2008
OK? v Comment:
(e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of
other slopes on the prop
x
OK? Comment: J ��
(8) Recommendations for the preparation of a detailed clearing and grading plan which specifically
identifies ve etation to be removed, a schedule for vegetation removal and replanting, and the
method of egetation removal.
OK? Comment:
(9) Recommendations for the preparation of a detailed temporary erosion control plan which
identifies t�e specific mitigating measures to be implemented during construction to protect the
slope frory(erosion, landslides and harmful construction methods.
OK? V Comment:
(10) An analyse of both on-site and off-site impacts of the proposed development.
OK? Comment:
(11) Spec
ific
at' ns of final development conditions such as, vegetative management, drainage,
erosion c ntrol, and buffer widths.
OK? vT Comment:
(12) Recommendations for the preparation of structural mitigation or details of other proposed
mitigatio .
OK? Comment:
(13) A site map drawn to scale showing the property boundaries, scale, north arrow, and the location
and nature of existing and proposed evel ment on the site.
OK? Comment:
Are the Documents signed and stamped?
Type and #of License:
If not approved, what is the next action/recommendation for further action?
V6 0 a 1 4 4 p--Aj 114 6� "
IT %V V %�V\ - 3 t IV,
t V
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