HomeMy WebLinkAboutGEO2022-00046 - BLD Engineering / Geo-tech Reports - 10/25/2021 00
RECEIVED
MAY 0 9 2022
�q 615 W. Alder Street
Geotechnical Report PLANNING
Ricketts Storage Facility
XXX E Dalby Road, Union
Parcel No. 32232-34-90012
Mason County, Washington
October 25, 2021
Project#21266
Prepared For:
Michael Ricketts
340 E Olympic Vista Drive
Union, WA 98592
Prepared By:
Envirotech Engineering
PO Box 984
Belfair, Washington 98528
Phone: 360-275-9374
PTV CLYDE ST
WASyq 9�ct
S
R 43045 cc�
�X, EC/STE
�s'rONAL EaG`
10/25/2021
1
MASON COUNTY Submittal Checklist
COMMUNITY SERVICES Geotechnical Report
riuxreq i'wmrnp nwmm.nrni ir.Nm rm+mimrcy ii.•irn
Instructions:
This checklist must be submitted with a Geotechnical Report and completed, signed, and stamped by the licensed
professional(s)who prepared the Geotechnical Report for review by Mason County pursuant to the Mason County
Resource Ordinance. If an item is found not applicable,the report should explain the basis for the conclusion.
Note: Unless specifically documented, this report does not provide compliance to the International Residential
Code Sections R403.1.7 for foundations on or adjacent to slopes, Section R403.1.8 for expansive soils or section
1808.7.1 of the International Building Code Section for Foundations on or adjacent to slopes.
Applicant/Owner Michael Ricketts Parcel# 32232-34-90012
Site Address XXX E Dalby Road
(1) (a) A discussion of general geologic conditions in the vicinity of the proposed development,
Located on page(s) 5
(b) A discussion of specific soil types,
Located on page(s) 6
(c) A discussion of ground water conditions,
Located on page(s) 7
(d) A discussion of the upslope geomorphology,
Located on page(s) 3
(e) A discussion of the location of upland waterbodies and wetlands,
Located on page(s) 3
(f) A discussion of history of landslide activity in the vicinity, as available in the referenced maps and
records.
Located on page(s) 8
(2) A site plan which identifies the important development and geologic features.
Located on Map(s) Site Plan—Appendix A
(3) Locations and logs of exploratory holes or probes.
Located on Map(s) Site Plan and Soil Logs (Appendix B)
(4) The area of the proposed development,the boundaries of the hazard,and associated buffers and
setbacks shall be delineated (top, both sides, and toe)on a geologic map of the site.
Located on Map(s) Site Plan
(5) A minimum of one cross section at a scale which adequately depicts the subsurface profile, and
which incorporates the details of proposed grade changes.
Located on Map(s) Soil Profile (Appendix B)
(6) A description and results of slope stability analyses performed for both static and seismic loading
conditions. Analysis should examine worst case failures. The analysis should include the Simplified
Bishop's Method of Circles.The minimum static safety factor is 1.5, the minimum seismic safety
factor is 1.1, and the quasi-static analysis coefficients should be a value of 0.15.
Located on page(s) 9 Page 1 of 35
ti
(7) (a) Appropriate restrictions on placement of drainage features,
Located on page(s) 16
(b) Appropriate restrictions on placement of septic drain fields,
Located on page(s) 17
(c) Appropriate restrictions on placement of compacted fills and footings,
Located on page(s) 14
(d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other slopes.
Located on page(s) 16
(e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes.
Located on page(s) 15
(8) Recommendations for the preparation of a detailed clearing and grading plan which specifically identifies
vegetation to be removed, a schedule for vegetation removal and replanting, and the method of vegetation
removal.
Located on page(s) 16
(9) Recommendations for the preparation of a detailed temporary erosion control plan which identifies the specific
mitigating measures to be implemented during construction to protect the slope from erosion, landslides and
harmful construction methods.
Located on page(s) 9
(10) An analysis of both on-site and off-site impacts of the proposed development.
Located on page(s) 11
(11) Specifications of final development conditions such as,vegetative management, drainage, erosion control, and
buffer widths.
Located on page(s) 17
(12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation.
Located on page(s) 17
(13) A site map drawn to scale showing the property boundaries, scale, north arrow, and the location and nature
of existing and proposed development on the site.
Located on Map(s) Site Plan
I, Michael Staten, hereby certify under penalty of perjury that I am a civil engineer licensed in the State of Washington
with specialized knowledge of geotechnical/geological engineering or a geologist or engineering geologist licensed in
the State of Washington with special knowledge of the local conditions. I also certify that the Geotechnical
PAL CLYDE ST Report, dated October 25, 2021 and entitled Ricketts Storage
Facility, meets all the requirements of the Mason County
Resource Ordinance, Geologically Hazardous Areas Section,
is complete and true,that the assessment demonstrates
r 43045. conclusively that the risks posed by the landslide hazard can
� Rf GIST ER �
�Sr�G'SAL�vG`� 10/25/2021 be mitigated through the included geotechnical design
recommendations, and that all hazards are mitigated in such a
Disclaimer: Mason County does not manner as to prevent harm to property and public health and
certify the quality of the work done in safety.
this Geotechnical Report.
Page 2 of 2
TABLE OF CONTENTS
1.0 INTRODUCTION.................................................................................................................................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.................................................................................................................3
2.4 SLOPE AND EROSION OBSERVATIONS................................................................................................4
3.0 SUBSURFACE INVESTIGATION.....................................................................................................5
3.1 FIELD METHODS,SAMPLING AND FIELD TESTING ...........................................................................5
3.2 GENERAL GEOLOGIC CONDITIONS....................................................................................................5
3.3 SPECIFIC SUBSURFACE CONDITIONS.................................................................................................6
3.3.1 Groundwater............................................................................................................................... 7
4.0 ENGINEERING ANALYSES AND CONCLUSIONS.......................................................................8
4.1 SLOPE STABILITY...............................................................................................................................8
4.1.1 Slope Stability Analysis..............................................................................................................9
4.2 EROSION..............................................................................................................................................9
4.3 SEISMIC CONSIDERATIONS AND LIQUEFACTION...............................................................................9
4.3.1 Liquefaction.............................................................................................................................. 10
4.4 LANDSLIDE,EROSION AND SEISMIC HAZARDS CONCLUSIONS....................................................... 10
4.5 LATERAL EARTH PRESSURES........................................................................................................... 10
4.6 ON-SITE AND OFF-SITE IMPACTS.................................................................................................... 11
5.1 BUILDING FOUNDATION RECOMMENDATIONS................................................................................ 12
5.L l Bearing Capacity...................................................................................................................... 12
5.1.2 Settlement.................................................................................................................................. 13
5.1.3 Concrete Slabs-on-Grade......................................................................................................... 13
5.2 EARTHWORK CONSTRUCTION RECOMMENDATIONS...................................................................... 13
5.2.1 Excavation................................................................................................................................ 13
5.2.2 Placement and Compaction of Native Soils and Engineered Fill........................................... 14
5.2.3 Retaining Wall Backfill............................................................................................................ 15
5.2.4 Wet Weather Considerations.................................................................................................... 15
5.2.S Building Pads........................................................................................................................... 15
5.3 BUILDING AND FOOTING SETBACKS................................................................................................ 15
5.4 SURFACE AND SUBSURFACE DRAINAGE........................................................................................... 16
5.5 VEGETATION BUFFER AND CONSIDERATIONS................................................................................. 16
5.6 TEMPORARY AND PERMANENT EROSION CONTROL....................................................................... 17
5.7 SEPTIC DRAINFIELDS........................................................................................................................ 17
5.8 STRUCTURAL MITIGATION............................................................................................................... 17
6.0 CLOSURE............................................................................................................................................18
Appendix A-Site Plan
Appendix B- Soil Information
Appendix C-Slope Stability
1.0 INTRODUCTION
Envirotech Engineering (Envirotech) has completed a geotechnical investigation for a planned
storage facility located at XXX E Dalby Road, identified as parcel number 32232-34-90012,
Mason County, Washington. See the vicinity map on the following page for a general depiction
of the site location.
An initial geotechnical evaluation of the project was conducted by Envirotech on October 19,
2021. 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. The planned development consists of multiple 1-story storage units, and other
ancillary features typical of this type of development. Approximate building footprint and other
features with relation to existing site conditions are illustrated on the Site Ma provided
proposed g P
in Appendix A of this report.
1.2 Purpose of Investigation and Scope of Work
The purpose of this geotechnical investigation is to assess geological hazards, and evaluate the
project in order to provide geotechnical recommendations that should be implemented during
development. The investigation included characterizing the general project surface and
subsurface conditions, and evaluating the suitability of the soils to support the planned site
activities.
In order to fulfill the purpose of investigation, the geotechnical program completed for the
proposed improvements of the project include:
• Review project information provided by the project owner and/ or owner's
representative;
• Conduct a site visit to document the site conditions that may influence the construction
and performance of the proposed improvements of the project;
• Define general subsurface conditions of the site by observing subsoils within test pits
Envirotech Engineering Geotechnical Report
PO Box 984 page 1 Parcel 32232-34-90012
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 October 25,2021
and/ or cut banks, review geological maps for the general area, research published
references concerning slope stability, and review water well reports from existing wells
near the project;
• Collect bulk samples,as applicable, at various depths and locations;
• Perform soils testing to determine selected index and/or engineering properties of the site
soils;
• Complete an engineering analysis supported by the planned site alterations, and the
surface and subsurface conditions that were identified by the field investigation, soil
testing,and applicable project research; and,
• Establish conclusions based on findings, and make recommendations for foundations,
drainage, slope stability, erosion control, earthwork construction requirements, and other
considerations.
N
E Warrer► Project
f -
y E Kuhn Av "r
1 _ Ue
D re
a I E Urnorl 7` �
E Qalby Rd _.
og E U " ..
f Sk
iff
yUBUe��c F �q@ C.
.� to ry Ciub or E
.. 0.4mi �r C tlen�el'tf! dl
Vicinity Map from Mason County Website
Envirotech Engineering Geotechnical Report
PO Box 984 page 2 Parcel 32232-34-90012
Belfair, Washington 98528 Mason County, Washington
Ph. 360-275-9374 October 25,2021
2.0 SURFACE CONDITIONS
Information pertaining to the existing surface conditions for the project was gathered on October
19, 2021 by a representative with Envirotech. During the site visit, the type of geotechnical
investigation was assessed, site features were documented that may influence construction, and
site features were examined that may be influenced by construction. This Surface Conditions
Section provides information on general observations, vegetation, topography, drainage and
observed slope/ erosion conditions for the project and surrounding areas that may impact the
project.
2.1 General Observations
Currently, the property is vacant with an existing ingress/ egress. Timber has mostly been
removed at the time of our site visit. Vegetation on and near the project consists primarily of
secondary growth firs, alders, blackberry and other trees and shrubbery common to this area of
the Pacific Northwest. An aerial photo of the project and immediate vicinity is provided on the
following page.
2.2 Topography
The topographic information provided in this section was extrapolated from a public lidar source,
and incorporated observations and field measurements. Where necessary, slope verification
included measuring slope lengths and inclinations with a cloth tape and inclinometer. See the Site
Plan in Appendix A in this report for an illustration of general topography with respect to the
planned development.
Critical descending slopes, with grades exceeding 40% appear to be within 300 feet of the
planned development. The maximum critical slope is approximately 56% with a vertical relief of
about 30 feet. Ascending grades are generally located to the north 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 and beyond is generally situated on a hillside of glacial
origin.
2.3 Surface Drainage
Runoff originating upslope of the development is mostly diverted away from the property by
accommodating topography. Excessive scour, erosion or other indications of past drainage
problems were not observed within the immediate vicinity of the planned development.
2.3.1 Upslope Water Bodies
There is an apparent wetland off site located upslope from the planned development.
However, we did not observe any indications that this water body would significantly
influence the project.
Envirotech Engineering Geotechnical Report
PO Box 984 page 3 Parcel 32232-34-90012
Belfair, Washington 98528 Mason County, Washington
Ph. 360-275-9374 October 25,2021
2.4 Slope and Erosion Observations
The slope gradients near the project signal a potential landslide or erosion hazard area. Some
indicators that may suggest past slope movements include:
• Outwash of sediments near the bottom of the slope,
• Fissures, tension cracks, hummocky ground or stepped land masses on the face or top of
the slope, and parallel to the slope,
• Fine, saturated subsurface soils,
• Old landslide debris,
• Significant bowing or leaning trees,or,
• Slope sloughing or calving.
These slope instability indicators or other significant mass wasting on the property or within the
general vicinity of the project were not observed or discovered during research. Indications of
past landslides, current unstable slopes, deep-seated slope problems, or surficial slope failures
were not observed during the site visit.
N
ilk
1
�• 'x a _ .'
y
Aerial Photo from Mason County Website
Envirotech Engineering Geotechnical Report
PO Box 984 page 4 Parcel 32232-34-90012
Belfair, Washington 98528 Mason County, Washington
Ph. 360-275-9374 October 25,2021
3.0 SUBSURFACE INVESTIGATION
Information on subsurface conditions pertaining to the project was primarily gathered on October
19,2021 by a representative with Envirotech.Applicable information on field methods,sampling,
field testing, general geologic conditions, specific subsurface conditions, and results from soil
testing are presented in this section of the report. Appendix B of this report includes pertinent
information on subsurface conditions for the project, such as subsoil cross-section(s), test pit
log(s), and applicable water well report(s). Water well reports were utilized to estimate ground
water levels,and if sufficient,were used in identifying subsoil types. Applicable test pit locations
are depicted on the Site Plan provided in the appendix of this report.
3.1 Field Methods,Sampling and Field Testing
Information on subsurface conditions for the project was accomplished by examining soils within
test pits and/ or nearby banks extending to depths of up to 4 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 36 to 48 inches, and
very dense soils from 36 inches to 48 inches to the depth of terminus.
3.2 General Geologic Conditions
In general, soils at the project are composed of materials from glacial advances. The geologic
conditions as presented in the "Geologic Map of Washington," compiled by J. Eric Schuster,
2002 indicates Quaternary sediments, Qg. Quaternary sediments are generally unconsolidated
deposits, and dominantly deposited from glacial drift, including alluvium deposits.This project is
located within the Puget Lowland. Typically, "lower tertiary sedimentary rocks unconformably
overlie the Crescent Formation."as revealed in the Geologic Map.Initial sedimentary rocks were
formed from shales, sandstones and coal deposits from rivers. During the Quaternary period,the
Puget Lowland was covered by numerous ice sheets,with the most recent being the Fraser glacier
with a peak of approximately 14,000 years ago. Upon the glacial retreat, the landscape was
formed by glacial erosion 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:
Qgt A'ashon lodgment till—Unsorted unstratified nix of clay.silt.sand gravel.and sparse boulders:
typically supported by a sandy matrix.mostly gray:compact.resembling concrete.
Envirotech Engineering Geotechnical Report
PO Box 984 page 5 Parcel 32232-34-90012
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 October 25,2021
' A
o,o, eo.ns
A ^I J
a,A,
49
O D
Project
r q A, r1
os
A & H QFft
47
a»
•
-Get
44
1m0' L 0 7-
low Am 3oa0 mow
�00o mm moo lom CFEi ,J
'.A ! s..f :J ..: S.`'n { �-.ls.:d�'}iw'.•.. :�iG ._ 3 f3r•''1 � h'�'= )�id '�
Geological Map Department of Natural Resources Washington State
3.3 Specific Subsurface Conditions
The following subsurface conditions are estimated descriptions of the project subgrade utilizing
information from the depth of penetration at all testing, sampling, observed and investigated
locations. Soils for this project were primarily described utilizing the Unified Soil Classification
System(USCS)and the Soil Conservation Service(SCS)descriptions.
The project is currently composed of native soils without indications of fill. Within test pit
locations, soils within the upper 4 feet of natural ground were generally observed to be moist,
brown silty sand with gravel (SM). Very dense, cemented glacial till was found to be between 36
inches and 48 inches below the ground surface.
The relative densities of the soil within selected test pits are provided above in Section 3.1.
Expanded and specific subsurface descriptions, other than what is provided in this section, are
provided in the soil logs located in Appendix B of this report.
According to the "Soil Survey of Mason County," by the United States Department of
Agriculture, Soil Conservation Service, the site soils are described as Alderwood Gravelly Loam,
Envirotech Engineering Geotechnical Report
PO Box 984 page 6 Parcel 32232-34-90012
Belfair,Washington 98528 Mason County, Washington
Ph. 360-275-9374 October 25,2021
A,,, with 0% - 15% slopes. The soil designations are depicted in the aerial photograph below, and
descriptions are provided in Appendix B of this report.
H
A
Zo 3M
Soil Survey from USDA Natural Resources Conservation Service
According to the USDA Textural Classification System, the site soils are primarily classified as
very gravelly sandy loam. Soil structure may be described as granular.
Based on the fines content, erodibility of the site soils is considered to be low to moderate.
However, soils on disturbed steep slopes are more apt to erode than disturbed soils on flatter
slopes. Based on the fines content and fraction of clay within the fines content, settleability of the
site soils is expected to be moderate to fast. Permeability is expected to be high for this site due
significance of moderate density,poorly graded granular soils.
Based on the soils gradation, site infiltration for stormwater facilities should be 4.2 inches/hour.
Lower hardpan soils encountered between 3 feet and 4 feet below the existing ground surface
virtually has a zero infiltration rate.
3.3.1 Groundwater
From the water well report(s)and knowledge of the general area, permanent groundwater
is at least 50 feet directly below the property at the building pad location. Surface seepage
or perched groundwater at shallow depths was not observed on-site, nor indicated on the
well reports.
Envirotech Engineering Geotechnical Report
PO Box 984 page 7 Parcel 32232-34-90012
Belfair,Washington 98528 Mason County, Washington
Ph. 360-275-9374 October 25,2021
4.0 ENGINEERING ANALYSES AND CONCLUSIONS
The following section includes slope stability, erosion, seismic considerations, and impacts to
both on-site and off-site properties.
4.1 Slope Stability
Landslides are natural geologic processes, and structures near slopes possess an inherent risk of
adverse settlement, sliding or structural damage due to these processes. Geotechnical engineering
cannot eliminate these risks for any site with sloping grades because gravity is constantly
inducing strain on the sloping soil mass. Excessive wet weather and/ or earthquakes will
exacerbate these strains. Geotechnical engineering considers excessive wet weather and `design'
earthquakes in order to provide an acceptable factor of safety for developing on or near sloping
terrain with relation to current engineering protocol. These factors of safeties are based on
engineering standards such as defining engineering properties of the soil, topography, water
conditions, seismic acceleration and surcharges. Surface sloughing or other types of surficial
slope movements usually do not affect the deep-seated structural capability of the slope.
However, repeated surficial slope movements, if not repaired, may present a threat to the
structural integrity of the slope. If any slope movement arises,the slope should be inspected by an
engineer. Subsequently,maintenance may be required in order to prevent the possibility of further
surficial or deep seated slope movements that may be damaging to life and property.
According to the 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 and high slope instability with relation to slopes. A Resource
Map from the DNR Forest Practices Application Review System is provided below:
N
X`=
Project
Sol/
Soils-Hydric Soils
E 6.OaLh!'cRdg ® .
Soils-Highly Unstable Soils
Soils-Highly Erodible Soils
— Westside Slope Stability Model(FP)
s Moderate Slope Instability
High Slope Instability
Resource Map from Washington State Department of Natural Resources Website
Envirotech Engineering Geotechnical Report
PO Box 984 page 8 Parcel 32232-34-90012
Belfair, Washington 98528 Mason County, Washington
Ph. 360-275-9374 October 25,2021
4.1.1 Slope Stability Analysis
The Simplified Bishop Method, utilizing `STABLE' software, was used to analyze the
static stability of the site slopes. Seismic conditions were estimated utilizing worst case
scenario values from the static analysis,a quasi-static analysis coefficient of at least 0.15,
and applying the applicable values to STABLE software. Various radii 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
regard 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:
Soil unit weight: 132 pcf
Angle of internal friction: 30 degrees
Cohesion: 200 psf
Based on the slope stability analysis, unacceptable factors of safety could be present on
and near the critical slope,but do not reflect conditions where development is expected to
occur. For this project, at the location of the proposed development, minimum factor of
safeties for static and dynamic conditions were estimated to be at least 1.5 and 1.1,
respectively. See the slope stability information in Appendix C for a depiction of
minimum factors of safety away from the project.
4.2 Erosion
Based on the USCS description of the project soils, the surface soils are considered moderately
D provided above
erodible. Accordingto the Resource Ma from the Washington State as ro
P gt �, P ,
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).
Due to the and magnitude of development, full erosion control plans are required for this
type � P t, P
project. Temporary and permanent erosion control measures are required for site development,
and shall be provided in a stormwater management plan.
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, which is approximately 3 miles to the north west of this
project. This information is based on the USGS Quaternary Fault and Fold Database for the
United States.
Envirotech Engineering Geotechnical Report
PO Box 984 page 9 Parcel 32232-34-90012
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 October 25,2021
Potential landslides due to seismic hazards have been considered, and are addressed in the Slope
Stability Analysis Section provided earlier in this report.
Soils immediately below the expected foundation depth for this project are generally Type D,
corresponding to the International Building Code (IBC) soil profiles. According to the IBC, the
regional seismic zone is 3 for this project. The estimated peak ground acceleration ranges from
0.50g to 0.60g.This estimation is based on the United States Geological Survey(USGS)National
Seismic Hazard project in which there is an estimated 2% probability of exceedance within the
next 50 years.
4.3.1 Liquefaction
The potential for liquefaction is believed to be low for this project. This is based, in part,
on the subsurface conditions such as soil characteristics and the lack of a permanent
shallow water table. Subgrade characteristics that particularly contribute to problems
caused from liquefaction include submerged, confined, poorly-graded granular soils (i.e.
gravel,sand,silt).Although gravel-and silt-sized soil particles could be problematic,fine
and medium grained sands are typically subjected to these types of seismic hazards. No
significant saturated sand stratifications are anticipated to be within the upper 50 feet of
the subsoil for this project.
4.4 Landslide,Erosion and Seismic Hazards Conclusions
DNR did not indicate historic landslide activity near the project. Mapped slope conditions, as
delineated by the Departments of Ecology and/ or Natural Resources, were considered in our
slope stability assessment. Based on the proximity and severity of mapped delineations with
respect to the proposed development, results of the aforesaid slope stability analysis, observed
surface conditions, and other pertinent information, it is our opinion that the proposed
development may occur in accordance with the recommendations in this geotechnical report.
4.5 Lateral Earth Pressures
Retaining walls may be utilized for this project. The lateral earth pressures exerted through the
backfill of a retaining wall are dependent upon several factors including height of retained soil
behind the wall, type of soil that is retained, degree of backfill compaction, slope of backfill,
surcharges,hydrostatic pressures,earthquake pressures,and the direction and distance that the top
of the wall moves. A structural or geotechnical professional should design retaining walls based
on specific conditions.
Soil parameters for the structural design of retaining walls may be estimated as 134 pounds per
cubic foot (pcf) and 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.
Envirotech Engineering Geotechnical Report
PO Box 984 page 10 Parcel 32232-34-90012
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 October 25,2021
4.6 On-Site and Off-Site Impacts
From a geotechnical position, it is Envirotech's opinion that the subject property and adjacent
properties to the proposed development should not be significantly impacted if all
recommendations in this report are followed. This opinion is based on the expected site
development, existing topography, existing nearby development, land cover, and adhering to the
recommendations presented in this report. Future development or land disturbing activities on
neighboring properties or properties beyond adjacent parcels that are upslope and/or downslope
from the subject property could cause problems to the subject property. For this reason, future
development or land disturbance near the subject property should be evaluated by a geotechnical
engineer.
Envirotech Engineering Geotechnical Report
PO Box 984 page I 1 Parcel 32232-34-90012
Belfair, Washington 98528 Mason County, Washington
Ph. 360-275-9374 October 25,2021
5.0 ENGINEERING RECOMAMNDATIONS
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; an project research analyses and conclusions as
d, ,
g P J Y
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 typical light-
framed commercial buildings. The recommended allowable bearing capacities and settlements as
presented below, consider the probable type of construction as well as the field investigation
results by implementing practical engineering judgment within published engineering standards.
Evaluations include classifying site soils based on observed field conditions and soil testing for
this project. After deriving conservative relative densities, unit weights and angles of internal
friction of the in-situ soils, the Terzhagi ultimate bearing capacity equation was utilized for
determining foundation width and depth. Foundation parameters provided herein account for
typical structural pressures due to the planned type of development. A structural analysis is
beyond the scope of a geotechnical report, and a structural engineer may be required to design
specific foundations and other structural elements based on the soil investigation. Stepped
foundations are acceptable, if warranted for this project. Continuous, isolated, or stepped
foundations shall be horizontally level between the bottom of the foundation and the top of the
bearing strata. The frost penetration depth is not expected to extend beyond 12 inches below the
ground surface for this project under normal circumstances and anticipated design features.
5.1.1 Bearing Capacity
Existing in-situ soils for this project indicates that the structure can be established on
shallow, continuous or isolated footings. Foundations shall be established on relatively
undisturbed native soil that is competent and unyielding. Alternatively, foundations may
be constructed on selective re-compacted native soil or compacted engineered fill as
described in the Earthwork Construction Recommendations Section of this report.
For a bearing capacity requirement of no more than 1500 psf, a minimum continuous
footing width of 12 inches shall be placed at a minimum of 18 inches below the existing
ground surface atop unyielding soils. For a columnar load of no more than 3 tons, a
circular or square isolated foundation diameter or width shall be at least 24 inches.
Foundation recommendations are made available based on adherence to the remaining
recommendations that are provided in this report. Alterations to the aforementioned
foundation recommendations may be completed upon a site inspection by a geotechnical
engineer after the foundation excavation is completed.
Envirotech Engineering Geotechnical Report
PO Box 984 page 12 Parcel 32232-34-90012
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 October 25,2021
5.1.2 Settlement
Total and differential settlement that a structure will undergo depends primarily on the
subsurface conditions, type of structure, amount and duration of pressure exerted by the
structure, reduction of pore water pressure, and in some instances, the infiltration of free
moisture. Based on the expected native soil conditions, anticipated development, and
construction abides by the recommendations in this report, the assumed foundation
system may undergo a maximum of 1.0 inch total settlement, and a maximum differential
settlement of 0.75 inch.
5.1.3 Concrete Slabs-on-Grade
Interior slabs, if utilized, should be supported on a minimum of 4 inches of compacted
coarse, granular material (Retained on U.S. Sieve #10 or greater) that is placed over
undisturbed, competent native subgrade or engineered fill per the Earthwork
Recommendations Section below.
The recommendations for interior concrete slabs-on-grade as presented herein are only
relevant for the geotechnical application of this project. Although beyond the scope of
this report, concrete slabs should also be designed for structural integrity and
environmental reliability. This includes vapor barriers or moisture control for mitigating
excessive moisture in the building.
5.2 Earthwork Construction Recommendations
Founding material for building foundations shall consist of undisturbed native soils to the
specified foundation depths. Compacted engineered fill, or selective re-compacted native soils
may be used to the extents provided in this Earthwork Construction Recommendations Section.
The following recommendations include excavations, subgrade preparation, type of fill, and
placement of fill for building foundations.
5.2.1 Excavation
Excavation is recommended to remove any excessive organic content or other deleterious
material, if present, beneath foundations and to achieve appropriate foundation depth.
Additional sub-excavation will be required for this project if the soils below the required
foundation depth are loose, saturated, not as described in this report, or otherwise
incompetent due to inappropriate land disturbing, or excessive water trapped within
foundation excavations prior to foundation construction.All soils below the bottom of the
excavation shall be competent, and relatively undisturbed or properly compacted fill. If
these soils are disturbed or deemed incompetent, re-compaction of these soils below the
anticipated footing depth is necessary. Excavations shall be completely dewatered,
compacted, and suitable before placement of additional native soil, engineered fill or
structural concrete.
Envirotech Engineering Geotechnical Report
PO Box 984 page 13 Parcel 32232-34-90012
Belfair, Washington 98528 Mason County, Washington
Ph. 360-275-9374 October 25,2021
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.
F❑❑TING
COMPACTED
NATIVE S❑ILS
OR ENGINEERED t
FILL
1
UNBISTURBED SUBGRADE�
Both engineered fill and native soils used as compacted fill should be free of roots and
other organics, rocks over 6 inches in size, or any other deleterious matter. Because of
moisture sensitivity, importing and compacting engineered fill may be more economical
than compacting disturbed native soils. Engineered fill shall include having the soils
retained on the No. 4 sieve crushed (angular), and should consist of the following
gradation:
U.S. Standard Sieve %Finer(by weight)
6" 100
3" 60— 100
No. 4 20—60
No. 200 0-8
Table 1
Particle Size Distribution of Engineered Fill
Compaction shall be achieved in compacted lifts not to exceed 6 inches for both native
soils and engineered fill, respectively. Each lift should be uniformly compacted to at least
95% of the modified Proctor maximum dry density (ASTM D 1557) and within 3% of
optimum moisture content. Each lift surface should be adequately maintained during
construction in order to achieve acceptable compaction and inter-lift bonding.
Temporary earth cuts and temporary fill slopes exceeding 4 feet in height should be
limited to a slope of 2:1 (horizontal:vertical). Utility trenches or other confined
excavations exceeding 4 feet should conform to OSHA safety regulations. Permanent cut
and fill slopes shall be limited to a slope of 2:1, unless otherwise approved by an
engineer.
Envirotech Engineering Geotechnical Report
PO Box 984 page 14 Parcel 32232-34-90012
Belfair, Washington 98528 Mason County, Washington
Ph. 360-275-9374 October 25,2021
5.2.3 Retaining Wall Backfill
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).If pavement or building loads are planned to be located within retaining
wall backfill, then 90% compaction is required. In addition, heavy construction
equipment should be at a distance of at least '/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.
5.2.4 Wet Weather Considerations
Due to the types of subsurface soils, additional provisions may be required during
prolonged wet weather. Every precaution should be made in order to prevent free
moisture from saturating the soils within excavations. If the bottom of excavations used
for footing placement changes from a moist and dense/hard characteristic as presented in
this report to muck or soft, saturated conditions, then these soils become unsuitable for
foundation bearing material. If this situation occurs, a geotechnical engineer should be
notified, and these soils should be completely removed and replaced with compacted
engineered fill or suitable native material as presented in this section.
5.2.5 Building Pads
Building pads for this project, if utilized, shall be constructed per the fill placement and
compaction recommendations as presented above. Both engineered fill and native soils
may be used for building pads. Building pad slopes shall be no steeper than 2:1 for both
compacted engineered fill and re-compacted native soils used as fill. Building pad fill
shall be"keyed" into the existing subgrade to a depth of at least 2 feet below the existing
ground surface. The term "keyed," as used here, implies that the interface between the
building pad and subgrade is horizontally level. Alternatively, building pads may be
keyed into the subgrade to the above specified depth,and stepped. Stepped fill should be
keyed into the subgrade at a minimum width of 10 feet. All footings shall be located at
least 5 feet away from the top of the engineered fill slope.
5.3 Building and Footing Setbacks
Provided that assumptions relating to construction occur and recommendations are followed as
presented in this report, the factor of safety for slope stability is sufficient for a 50 feet footing
Envirotech Engineering Geotechnical Report
PO Box 984 page 15 Parcel 32232-34-90012
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 October 25,2021
setback from the face of the nearby descending slopes exceeding 40%. See the figure below and
the Site Plan in Appendix A for an illustration of the setbacks.
STRUCTURE
TOP OF
SLOPE SLOPE
FACE
�—— SETBACK - I FOOTING
From the illustration above, structures may be located closer to the top of slope by extending the
foundation deep enough to maintain the recommended setback. In addition, the required setback
may be reduced by mitigation,and subsequently would require additional geotechnical studies.
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.
Since impervious thresholds are exceeded per the prevailing agency code,engineered stormwater
management plans are required for this project. Envirotech will complete stormwater plans under
a separate cover that will account for the geotechnical aspects of this project.
For this project, infiltration is feasible where soils permit. The shallow cemented till layer allows
for limited infiltration that shall be accounted for in the design and construction. Any other
drainage protocol is feasible from a geotechnical standpoint.
5.5 Vegetation Buffer and Considerations
For this project, we believe that a detailed clearing and grading plan is not warranted unless the
prevailing agency thresholds are exceeded, and basic vegetation management practices should be
adhered to.
Ve gtation Buffer—Vegetation shall not be removed from the face of the critical slope or within
S g l�
a distance of 25 feet beyond the top of the slope. However, any tree deemed hazardous to life or
property shall be removed. If tree removal is necessary, then stumps and roots shall remain in
place, and the underbrush and soil shall remain undisturbed as much as possible. Any disturbed
soil shall be graded and re-compacted in order to restore the terrain similar to preexisting
Envirotech Engineering Geotechnical Report
PO Box 984 page 16 Parcel 32232-34-90012
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 October 25,2021
conditions and drainage patterns. See the Site Plan in Appendix A of this report for a depiction of
the vegetation buffer.
5.6 Temporary and Permanent Erosion Control
From a geotechnical position, ordinary temporary and permanent erosion control is sufficient 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.
Erosion control during construction should include minimizing the removal of vegetation to the
least extent possible. Erosion control measures during construction may include stockpiling
cleared vegetation, silt fencing, intercepting swales, berms, straw bales, plastic cover or other
standard controls. 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.
Additional erosion control information and specifications may be found in the applicable
"Stormwater Management Manual for Western Washington," prepared by the Washington State
Department of Ecology Water Quality Program.
5.7 Septic Drainfields
Septic drainfields are not expected to be an element of this project. However, if septic systems are
proposed,there are no issues with this property from a geotechnical perspective.
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 Geotechnical Report
PO Box 984 page 17 Parcel 32232-34-90012
Belfair,Washington 98528 Mason County, Washington
Ph. 360-275-9374 October 25,2021
6.0 CLOSURE
Based on the project information provided by the owner, the proposed development, and site
conditions as presented in this report, it is Envirotech's opinion that additional geotechnical
studies are not required to further evaluate this project.
Due to the inherent natural variations of the soil stratification and the nature of the geotechnical
subsurface exploration, there is always a possibility that soil conditions encountered during
construction are different than those described in this report. It is not recommended that a
qualified engineer performs a site inspection during earthwork construction unless fill soils will
influence the impending foundation. However, if native, undisturbed subsurface conditions found
on-site are not as presented in this report,then a geotechnical engineer should be consulted.
This report presents geotechnical design guidelines, and is intended only for the owner, or
owners' representative,and location of project described herein.This report should not be used to
dictate construction procedures or relieve the contractor of his responsibility.
Any and all content of this geotechnical report is only valid in conjunction with the compliance of
all recommendations provided in this report. Semantics throughout this report such as `shall,'
`should' and `recommended' imply that the correlating design and/or specifications must be
adhered to in order to potentially protect life and/or property. Semantics such as `suggested' or
`optional' refer that the associated design or specification may or may not be performed, but is
provided for optimal performance. The recommendations provided in this report are valid for the
proposed development at the issuance date of this report. Changes to the site other than the
expected development, changes to neighboring properties, changes to ordinances or regulatory
codes, or broadening of accepted geotechnical standards may affect the long-term conclusions
and recommendations of this report.
The services described in this report were prepared under the responsible charge of Michael
Staten, a professional engineer with Envirotech. Michael Staten has appropriate education and
experience in the field of geotechnical engineering in order to assess landslide hazards,
earthquake hazards,and general soil mechanics.
Please contact Michael Staten at 360-275-9374 if you have any questions, comments, or require
additional information.
Sincerely,
Envirotech Engineering
Jessica Smith,M.S. Michael Staten,P.E.
Staff Geologist Geotechnical Engineer
Envirotech Engineering Geotechnical Report
PO Box 984 page 18 Parcel 32232-34-90012
Belfair,Washington 98528 Mason County,Washington
Ph. 360-275-9374 October 25,2021
APPENDIX A
SITE PLAN
I
SCALE. 1 INCH- 150 FEET
25 FT VEGETATION
REMOVAL BUFFER FROM TOP
OF CRITICAL SLOPE
APPROXIMATE TOP OF
CRITICAL SLOPE
EXCEEBM 40%
OUTLINE OF POSSIBLE 50 FT CONSTRUCTION
BUILDING AREA SETBACK FROM TOP OF
(GEOTECHNICAL OLY) 20o CRITICAL SLOPE
N
- - - - - - - - - -I ,tt
V V
PROPERTY LINE ep ' r APPROXIMATE TOE
OF CRITICAL SLOPE
S0 FT TRUCTION EXCEEDING 40%
S K FROM TOP 2
ITICAL SLOPE
�* TP1@ `q?
w1 �
25 F VEGETATION
REMOVAL BUFFER - -
FROM CRIT!TOL P_SL OFOPE`, - ---_-.
EXISTING DRIVEWAY
- � x
E D LBY ROAD
APPROXIMATE TOP A
OF CRITICAL SLOPE
EXCEEDING 40%
APPROXIMATE TOE
OF CRITICAL SLOPE
EXCEEDING 40%
PROJECT/ OWNER/ LOCATOOw
NOTES, SINGLE FAMILY RESIDENCE
1.CONTOURS WERE NOT PREPARED BY A LICENSED LAND SURVEYOR. GEOTECHNICAL REPORT
CONTOURS WERE EXTRAPOLATED FROM A PUBLIC LIDAR SOURCE, AND RICKETTS
INCORPORATED FIELD MEASUREMENTS AS EXPLAINED IN THE GEOTECHNICAL EPORT. XX% E DALBY ROAD
R
LEGEND PARCEL 32232-34-90012
2. BOUNDARIES WERE NOT PREPARED BY A LICENSED SURVEYOR. LOCATIONS MASON COUNTY, WASHINGTON
ff SITE FEATURES THAT ARE SHOWN HERE, SUCH AS TOP OF SLOPES, TOE ENGINEER-
13F SLOO'ES,WATER FEATURES,ETCH., WITH RELATION TO THE PROPERTY -y SLOPE INDICATOR ENVIROTECH ENGINEERING
LINES MUST BE VERIFIED BY THE OWNER, RECOMMENDATIONS IN THE PO BOX 984
GEOTECHNICAL REPORT PROVIDE SETBACKS, BUFFERS, DEPTHS, ETC.. WITH EXISTING CONTOUR BELFAIR, WASHINGTON 98528
RELATION TO GEOLOGIC FEATURES, NOT PROPERTY LINES. THESE GEOLOGIC 360-275-9374
FEATURES MAY BE LOCATED ON THE SUBJECT PROPERTY 132 NEIGHBORING Tpl e TEST PIT
PROPERTIES. SITE PLAN
APPENDIX B
SOEL INFORMATION
VERTICAL MR HORIZONTAL SCALE,
SCALE, I INC14 60 FEET
CUTS FOR GRADING AND
POSITIVE DRAINAGE.
SEE REPORT. DRIVEWAY
VARIABLE MEDIUM DENSE SILTY SAND
WITH GRAVEL (SM) 211 FILL AS NEEDED
SEE REPORT
EXISTING GRADE
90�* �E DALBY ROAD
VERY DENSE, CEMENTED TILL
SECTION A-A
PROJECT/ OWNER/ LOCATION
SINGLE FAMILY RESIDENCE
GEOTECHNICAL REPORT
RICKETTS
XXX E DALBY ROAD
PARCEL 32232-34-90012
MASON COUNTY, WASHINGTON
ENGINEER,
ENVIROTECH ENGINEERING
PO BOX 984
BELFAIR, VASNINGTON 98528
360-275-9374
SOIL PROFILE
TEST PIT LOG
TEST PIT NUMBER TP-1
PROJECT: Ricketts Geotechnical Report DATE OF LOG: 10/19/2021
PROJECT NO: 21266 LOGGED BY: MCS
CLIENT: Ricketts EXCAVATOR: N/A
LOCATION: XXX E Dalby Road 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 ILL PI CURVE
AND TEST DATA DEPTH N 10 30 50
0 .....................
.e•.
SM Brown,moist SILTY SAND with gravel.
Z A" .; medium dense.Gravel is well-graded
and subrounded.Sand is medium and
1 coarse.Non-plastic.
2
3
Cemented glacial till
4
Excavation terminated at approximately 4
feet
5
6
7
8
9
10
No Groundwater Encountered ENVIROTECH ENGINEERING
This information pertains only to this boring and should not be Geotechnicai Engineering
interpreted as being indicitive of the entire site.
TEST PIT LOG
TEST PIT NUMBER TP-2
PROJECT: Ricketts Geotechnical Report DATE OF LOG: 10/19/2021
PROJECT NO: 21266 LOGGED BY: MCS
CLIENT: Ricketts EXCAVATOR: N/A
LOCATION: XXX E Dalby Road 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 SILTY SAND with gravel,
medium dense.Gravel is well-graded
and subrounded.Sand is medium and
1 coarse.Non-plastic.
2
3
Cemented glacial till
4 Excavation terminated at approximately 4
feet
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 indicitrve of the entire site.
TEST PIT LOG
TEST PIT NUMBER TP-3
PROJECT: Ricketts Geotechnical Report DATE OF LOG: 10/19/2021
PROJECT NO: 21266 LOGGED BY: MCS
CLIENT: Ricketts EXCAVATOR: N/A
LOCATION: XXX E Dalby Road 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 SILTY SAND with gravel,
t medium dense.Gravel is well-graded
and subrounded.Sand is medium and
1 coarse.Non-plastic.
2
Cemented glacial till
3 Excavation terminated at approximately 3
feet
A
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 indicitive of the entire site.
Map Unit Description_Alderwood gravelly loam,0 to 15 percent slopes--Mason County,
Washington
Mason County, Washington
Aa—Alderwood gravelly loam, 0 to 15 percent slopes
Map Unit Setting
National map unit symbol: 2t62h
Elevation: 50 to 800 feet
Mean annual precipitation: 25 to 60 inches
Mean annual air temperature: 48 to 52 degrees F
Frost-free period: 160 to 240 days
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Alderwood and similar soils:85 percent
Minor components:15 percent
Estimates are based on observations,descriptions.and transects of
the mapunit.
Description of Alderwood
Setting
Landform:Hills.ridges
Landform position(two-dimensional):Shoulder
Landform position(three-dimensional):Nose slope,talf
Down-slope shape:Convex,linear
Across-slope shape:Convex
Parent material,Glacial drift and/or glacial outwash over dense
glaciomarine deposits
Typical profile
A-0 to 7 inches. gravelly loam
Bwi-7 to 21 inches: very gravelly sandy loam
Bw2-21 to 30 inches: very gravelly sandy loam
Bg-30 to 35 inches: very gravelly sandy loam
2Cdl-35 to 43 inches: very gravelly sandy loam
2Cd2-43 to 59 inches: very gravelly sandy loam
Properties and qualities
Slope:0 to 15 percent
Depth to restrictive feature:20 to 39 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 37 inches
Frequency of Hooding:None
Frequency of ponding:None
Available water supply,0 to 60 inches: Very low(about 2.8 inches)
Interpretive groups
Land capability classification(irrigated): None specified
Land capability classification(nonIrrigated): 4s
Hydrologic Soil Group: B
USD1 Natural Resources Web Sod Survey 10/22/2021
�i Conservation Service National Cooperative Sod Survey Page 1 of 2
r
Map Unit Description Aidenvood gravelly loam,0 to 15 percent slopes—Mason County,
Washington
Ecological site: F002XA004WA-Puget Lowlands Forest
Forage suitability group: Limited Depth Soils(G002XF303WA),
Limited Depth Soils(G002XN302WA)
Other vegetative classification: Limited Depth Soils
(G002XF303WA),Limited Depth Soils(G002XN302WA)
Hydric soil rating: No
Minor Components
Everett
Percent of map unit:5 percent
Landform:Eskers,kames,moraines
Landform position(two-dimensional):Shoulder,footslope
Landform position(three-dimensional):Base slope.crest
Down-slope shape:Convex
Across-slope shape:Convex
Hydric soil rating: No
McKenna
Percent of map unit:5 percent
Landform:Drainageways,depressions
Landform position(three-dimensional):Dip
Down-slope shape:Linear,concave
Across-slope shape:Concave
Hydric soil rating: Yes
Shalcar
Percent of map unit:3 percent
Landform:Depressions
Landform position(three-dimensional):Dip
Down-slope shape:Concave
Across-slope shape:Concave
Hydric soil rating: Yes
Norma
Percent of map unit:2 percent
Landform:Depressions,drainageways
Landform position(three-dimensional):Dip
Down-slope shape:Concave,linear
Across-slope shape:Concave
Hydric soil rating: Yes
Data Source Information
Soil Survey Area: Mason County,Washington
Survey Area Data: Version 17,Aug 31,2021
Natural Resources Web Sal Survey 1012212021
Conservation Service National Cooperative Soil Survey Page 2 of 2
---
+r File.rdtm land Fist C"Py with WATER WELL REPORT' -Wulecauon No.
L Department n(Ecolory /
QSecond COPY—Ownet's Copy
ITtrtl CuVY—Drnle is CopySTA'j'/IC OF WAARWGION Permit Nq!�a•C,�,.
_L"^7V•1 .. .. L^�i.l.Y..eF._�
Address___..__._...... ._(I) Gv►'NER: Name_ __.. _..._.. -..__... _ . ._.� . _ ... ..
(2) LOCATION OF WELL: talent+.._. .. ... .. __-•-- _ - . _ty.. _..!:see
/� -� 3a To�N.tl.�(L�W.M.
Rrering and_distance from seeUon or subdivision mrne, 1,009 p r 71
—
(3) PROPOSED USE: Domestic L lndustrtat ❑ attlitdlial❑ (10) WELL LOG:
iIrnestlon C] Test VftU 13 close ❑ Formation:Dercrtbe be eater,chanter+,Sias of rnalerral and structure,and
C show thickness at int"1012 area the kind and aaeurr of the matrroal in each
(4) TYPE OF WORK: """er's numoer or wen rennin pr"etrated,wrath at leaµ on,entry for cock chaape of formation.
__ --
u *reel.. MATERIAL more in—* -- -
1gATERIAL FROM TO
New weLl p Method:{Pug- ❑ three'0 —
YDeepened 0 _.Cable ❑ 'Ltblan_0
t0 Reeond)tioned❑ _aotar7.J] f:alyte Q r
• r
L. (5) DIMENSIONS: Diameter of waltz......'.. 4 --- 3
�Q�:r�haY.' Y ri7 ifs'
tH
Drilled.___._..__.._ft. Depth of mynilded.Mir1L..L�7_.:__11. __._._....— li♦ _.r
(6) CONSTRUCTION DETAILS: Aw
--
,_., Casing installed: "Di—eras._- ff,to. .'sL YY' TYB -
Threaded❑ ___.._.."Dtam.team- _fK W. R• t s
0 Wattled❑ ..___..'•Dlam-
Perforations: Yea No❑
Type of perforator used r
•R+ StZS of perforauoeu......._..._.:_—..:•ti.bi••: _
penoratlona from ...Z_ .-!t.
....__.perroratluas from—&Vz-_ ft.to__..ea}.s,.;.fL _
perforsuo"from -- .Ji<'to
Screens: yes 10 No O
+T' autat'Iurfre Nast Mu —
c
Typ..._..- _..._...__.._ _.__ the-•-- -
iImam..._.._._-Slot aide_..._____fr'aat.._•rv.a..lt.1• ...-•-!C - - _ --'
D1am.._......_.Stan afar..—._._front_._.__.'ft.I*-.. --
Grovel packed: yes t6p famel.grYanl
O ll Placed
z Surface Heil: Yes❑ no Q 2b os nl drpthl
Material used to
0 Did any straw contain uausable^walerr yes-Lr^ No CL
Type of water/_..._.__.....,_... _ D pLh of stroll..__,.--"--•.— ..... _ -.' .
T Method of sealing strata aft_.----.-._....---__..............__..____.__ -
0 (7) PUMP: ,�—
O —
W (8) WATER LEVELS: mnd m a�K`le"s��i'�::: -
...
p .n.below top of wall
Static level _.._. .._ - --- t. '•- ' � ••
ar Artesian Preen_.—_. .............Itis.per epuar InM
Arteaian water V controlled by................._..._... � __._._.__.
(9) WELL TESTS: lDa wdored below e�uUoct le4aeter lewd is_ ---a--•----- --•
work la____
fl. Was a pump test made? Yes❑ No❑ 11 Yea,by whom?
fV Yield. gal-/Mia.with R.drawdown'sper hrs. WELL DRILLERS.STATEMENT-
•' This well was drilled under my furisdietiap cad tbiS replart is
•• _ true td the beat of my knowledge and belief.
Recovery daW Itirre Laken as zero when _
tvaaeured from weD top to water levellPtlrtlF�YtMd bite f'ttisla Lre1 C`
t1 Tine Water level 1 Time Wale,Level fi Matey revel NAME......_.__ ......`Q .._ ..
IPareon. .....or corporatl (7ype or pneN
Q .._...._._.............._................................_....._...... .._............._...
__r.._.._...
_ ... ......._..................._...___....._............ ... .................. _.. ._.. Address-.---*..---..-...---.....--.-......_.._..._
_ .._.......... ..... ._..._ __».» _ _..._. ... ._......
_........._........_.»
Date of tent__.._._._____._.._..... .-...
[Signed]......_..._.._�......__..._... .... ............._................._.....
Hailer test....—._._saVitla.MIa--_.____-t.Arawrlorrrt
An.1—flow --..._...-...........gV.=. DetR....._......
..._..__..___.__...._.... �.-
Temperaturc of water..-_—_Wan m a thef t cal anslysla mat yes❑ ._.._No❑ UCenae Nth----__- -- .._......_......Date....�: ....:j...__...•�.,19.rip
�L 1USE ADDITIONAL SHLSrS rF NECESSARY)
7.F.No.J73t—OS—IRra.MTl). J�tyt � .f'� 'a
1
APPENDIX C
SLOPE STABILITY
i
4 1 . O 0
1 . 1 0
1 . 20
1 . 30
1 . 40
1 . 50
1 . 60
1 . 7 0
1 . 80
1 90
6^7
P r o c t Ri p o r L
DeatnZilf Dynamic Anaalyaim
Analymia 813Yiop
ura ...... ... w......... s.a
1 . O O
1 . 1 O
1 . 2 O
1 _ 3 0
1 . 4 O
1 . 50
1 . 6 0
1 . 7 0
1 . so
1 _ 90
=2 _ 00
63--
D aI--a t i 1 e S t a t i c Ana 1 y s i n
Analymim Sial-iop