HomeMy WebLinkAboutGEO2011-00010 for BLD2011-00110 and 00111 - GEO Geological Review - 2/25/2011 MASON COUNTY
DEPARTMENT OF COMMUNITY DEVELOPMENT
Planning Division
P O Box 279, Shelton, WA 98584
flo
(360)427-9670
Geotechnical Assessment Review Acceptance Letter
February 25, 2011
KEN GIESE
221 NE HAVEN LAKE DR
TAHUYA WA 98588
Case No.: GE0201 1-00010
Parcel No.: 223305000300
Proiect Description: GEO ASSESSMENT FOR BLD2011-00110 and BLD2011-00111.
The Geotechnical Assessment for KEN GIESE has been received and reviewed by the Planning
Department. The assessment was prepared by Michael Staten dated 12/9/2010.
Based on the certification provided by the licensed engineer/geologist, the referenced Geological
Assessment was prepared in general accordance with the requirements in the Mason County
Resource Ordinance, Landslide Hazard Areas 17.01.100.E.4. 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 assessment may be required to address these changes.
The assessment 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 Geological
Assessment.
Please contact me at (360) 427-9670, ext. 365 if you have questions.
Sinc rely
Allan Borden
J
Land Use Planner
Mason County Planning Department
Comments:
2/25 2• �11 Pa e 1 of 1 GE02011-00010
a
Mason County Review Checklist
For a Geological Assessment
Instructions:
This checklist is intended to assist Staff in the review of a Geological Assessment. The
Assessment 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
Assessment 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:
Permit# t'V ' 00 (W Parcel# 22� ✓ Sb 60300
Date(s)of the Document(s) reviewed: 0 0;�Q
4
(1) A discussion of geologic conditions in the general vicinity of the
proposed development, with geologic unit designation based
on refere ed maps.
OK? Comment:
(2) (a)A di sion of the ground water co ditigns at the site,
OK? , Comment: t�
(b) A disc sion of the estimated deptht'o w ter
OK?Comment: , ]
(c) A disc sion of the quantity of surfa e e age
OK?Comment:
(d) 7d�'s
scssion of the upslope geomoxph o y
OK? Comment: je) ssion of location of upl '.at, bodies and wetlands.
OK? Comment: C4
(3) The appr ate depth to hard or de An -of
tent soil, e.g. glacial till or outwash sand.
OKY L/ omment: T
(4) A discussion of any geomorphic expressi past slope instability(presence of
hummocky ground or ground cracks, terraced topography indicative of landslide block
movement, owed or arched trees iodicating downslope movement, etc.).
OK?_J Z Comment: j
(5) A discussion of the history of land lide activity in the vicinity, as available in the
referenced maps and records.
OK? omment:
(6) An opinion on whether the proposved development is within the landslide hazard area or
its associated buffer or setback and the potential for landslide activity at the site in light of
the proposed development. �J
OK? Comment:
(7) A reco mendation by the preparer whether a Geotechnical Report should be required to
further evaluate site conditions and the,proposed development of the subject property.
OK?_(Comment: 1yI I tl
(8) If the presence of a hazard is jifeterfinined within 300 feet of the proposed development,
then the following are delineated on a geologic map/siYe map:
(a) the area 2of the proposed development, / �[/
OK? omment: yV
Page 1 of 2 Form Effective June 2008
(b) the boundaries of the landslide hazard ar a (top, both sides, and toe),
OK? Comment: p �,
(c) the associated buffers (top, both sides, and toe) ,�
} OK? Comment: �/&
(d) building or other setbacks (top, both sides, and toe)
OK? Comment:
(9) A site map drawn to scale showing the property bountlaries, scale, north arrow, and the
location an ature of existing and proposed el ent on the site.
OK?�omment:
Are the Document(s)signed and stamped? .
Type and #of License:
If not approved, what is the next action/recommendation for further action? t(
l
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
RECEIVED
FEB 14 2011
Mason County DepartmeA9W-G finity Development
Submittal Checklist For a Geoloqical Assessment
Instructions:
This checklist must be submitted with a Geological Assessment and completed, signed, and
stamped by the licensed professional(s) who prepared the Geological Assessment for review by
Mason County pursuant to the Mason County Resource Ordinance. If an item found to be not
applicable, the report should explain the basis for the conclusion.
Applicant/Owner Ie5e, Parcel �0
# Z2330 50 0030
Site Address Z2 I AAA Hn vm 1-pkz-, Drive , L;-A4ea _
(1) A discussion of geologic conditions in the general vicinity of the
proposed development, with geologic unit designation based
on referenced maps. s.
Located on page(s)
(2) (a) A discussion of the ground water conditions at the site,
Located on page(s) C
(b) A discussion of the estimated depth to water
Located on page(s) rn
(c) A discussion of the quantity of surface seepage
Located on page(s) 4
(d) A discussion of the upslo a geomorphology
Located on page(s)
(e) A discussion of location of upland waterbodies and wetlands.
Located on page(s) 3
(3) The approximate depth to h rd or dense competent soil, e.g. glacial till or outwash sand.
Located on page(s)
(4) A discussion of any geomorphic expression of past slope instability (presence of
hummocky ground or ground cracks, terraced topography indicative of landslide block
movement, bowed or arched trees indicating downslope movement, etc.).
Located on page(s) 3
(5) A discussion of the history of landslide activity in the vicinity, as available in the
referenced maps and records.
Located on page(s) 74 9
(6) An opinion on whether the proposed development is within the landslide hazard area or
its associated buffer or setback and the potential for landslide activity at the site in light of
the proposed development.
Located on page(s) 7
(7) A recommendation by the preparer whether a Geotechnical Report should be required to
further evaluate site conditions and the proposed development of the subject property.
Page 1 of 2 Form Effective_tune 2008
i
Located on page(s) ffA6-it)
(8) If the presence of a hazard is determined within 300 feet of the proposed development,
then the following are delineated on a geologic map/site map:
(a) the area of the proposed )evelopment,
Located on Map(s) A1 4
(b) the boundaries of the Ian slide hazard area (top, both sides, and toe),
Located on Map(s)
(c) the associated buffers (-top, both sides, and toe)
Located on Map(s) a
(d) building or other setbacks op, both sides, and toe).
Located on Map(s)
(9) A site map drawn to scale showing the property boundaries, scale, north arrow, and the
location and nature of exist! g and propo ed development on the site.
Located on Map(s) S, p u
I, AIOU-1 544:on hereby certify under
penalty of perjury that 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 Geological Assessment, dated c,• 9, Zero, and entitled r,eo
ie ;� a o meets all the requirements of the
Mason County Reso rce Ordinance, Landslide Hazard Sec ion, 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)
CL Dgs�'��►
lZAM/0
'sfDNAL
Disclaimer: Mason County does not certify the quality of the work done in this Geological
Assessment.
Page 2 of 2 Form Effective June 2008
I
66o 2011 • Ow10
`fit d 01 I - 00 110 RECEIVED
FEB 14 2011
TO BE KEPT IN THE 426 W. CEDAR ST.
PARCEL FILE
PLANNING
Geological Assessment
for
Giese Single Family Residential Property
190 NE Haven Lake Drive
Parcel No. 22330 50 00300
Mason County, Washington
December 9, 2010
Project #10123
Prepared For:
Ken Giese
221 NE Haven Lake Drive CLYOF sT
Tahuya, Washington 98588 ���,P�°ti` ASf`��c�
Prepared By:
Envirotech Engineering 43045
74 NE Hurd Road "A ISTV,
Belfair, Washington 98528 S8I()NA0-
Phone: 360-275-9374
Fax: 360-275-4789
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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
2.3 SURFACE DRAINAGE.....................................................................................................................3
2.3.1 Upland Water Bodies and Geomorphology........................................................................... 3
2.4 SLOPE AND EROSION OBSERVATIONS...........................................................................................3
3.0 SUBSURFACE INVESTIGATION.................................................................................................5
3.1 FIELD METHODS,SAMPLING AND FIELD TESTING........................................................................5
3.2 GEOLOGIC CONDITIONS...............................................................................................................5
3.3 SPECIFIC SUBSURFACE CONDITIONS.............................................................................................5
3.3.1 Groundwater......................................................................................................................... 6
3.4 SOILS TESTING.............................................................................................................................6
3.4.1 Visual Classification............................................................................................................. 6
4.0 ENGINEERING CONCLUSIONS..................................................................................................7
4.1 LANDSLIDE HAZARDS...................................................................................................................7
4.1.1 Landslides and Slope Stability Analysis................................................................................8
4.1.2 Septic Drainfield Impacts...................................................................................................... 9
4.1.3 Surface and Subsurface Drainage........................................................................................ 9
4.1.4 On-Site and Off-Site Impacts................................................................................................ 9
4.2 EROSION HAZARDS.......................................................................................................................9
4.3 SEISMIC HAZARDS........................................................................................................................9
4.4 OTHER CONSIDERATIONS........................................................................................................... 10
5.0 CLOSURE..................................................................................................................................... 11
Appendix A- Site Plan
Appendix B - Soil Information
Soil Logs
Well Reports
1.0 INTRODUCTION
Envirotech Engineering (Envirotech) has completed this geological assessment for a residential
property located at 190 NE Haven Lake Drive, identified as parcel number 22330 50 00300 in
Mason County, Washington (Project). As presented herein, this assessment 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 soils descriptions in the
Subsurface Investigation Section; and, assessments for landslides, erosion, seismic hazards, and
other considerations in the Conclusions Section.
An initial geological/ geotechnical evaluation of the Project was conducted by Envirotech with
the property owner, Ken Giese, on November 19, 2010. It was determined that natural slopes
between 15%and 40% were present within 300 feet of the Project. Due to these slope grades, a
geological assessment is required pursuant to landslide hazard areas of the Mason County
Resource Ordinance (MCRO). During the evaluation and site visit by Envirotech, surface and
subsurface conditions were assessed. After completion of the field work and applicable Project
research, Envirotech prepared this geological assessment.
1.1 Project Information
Information pertaining to the Project was provided by the property owner with general
assumptions by Envirotech that are typical of this type of development. The property is accessed
from NE Haven Lake Drive, a paved roadway in Tahuya. The property consists of an unimproved
driveway, and building pad. The proposed development is expected to consist of a new single
family residence, on-site septic system, and other ancillary features. Foundation construction is
anticipated to be continuous strip footings. All drainage collected from foundations, roofs and/or
retaining walls are expected to have a protected outfall located downslope from the proposed
structures. Approximate site development with relation to existing site features are illustrated in
the Site Map in Appendix A.
1.2 Purpose of Investigation and Scope of Work
The purpose of this geological assessment was to evaluate the Project in order to confirm that the
proposed development is outside of any landslide hazard area and its associated buffers and
setbacks as determined in the MCRO. The investigation included characterizing the general
Project surface and subsurface conditions,and evaluating the suitability of the soils to support the
planned site development. In order to fulfill the purpose of investigation, the geological/
geotechnical program completed for the proposed improvements of the Project include:
• Review project information provided by the Project owner's representative;
• Conduct a site visit to document the site conditions that may influence the construction
and performance of the proposed improvements;
• Define general subsurface conditions of the site by observing soils within test pit
excavations, review well logs from existing wells near the Project, and evaluate
geological maps depicting the site geology for the vicinity of the Project;
• Perform soils testing, such as visual classifications,to determine selected index properties
of the soils;
• Complete an engineering assessment supported by planned site alterations and the surface
and subsurface conditions that were identified by the field investigation, soil testing, and
Envirotech Engineering Giese Geological Assessment
Ph. 360-275-9374 page 1 Parcel 22330 50 00300
Fax: 360-275-4789 Mason County, Washington
December 9,2010
applicable Project research; and,
• Establish engineering conclusions based on findings and anticipated Project.
Envirotech Engineering Giese Geological Assessment
Ph. 360-275-9374 page 2 Parcel 22330 50 00300
Fax:360-275-4789 Mason County,Washington
December 9,2010
2.0 SURFACE CONDITIONS
Information pertaining to the existing surface conditions for the Project was gathered on
November 18, 2010 by Michael Staten, geotechnical engineer with Envirotech. During the site
visit, site features were documented that may influence construction or reveal potential geological
hazards. This Surface Conditions Section provides information on general observations,
vegetation, topography, drainage and slope/ erosion conditions for the Project and surrounding
areas.
2.1 General Observations
The Project is currently vacant land with few improvements as previously mentioned, and
surrounded by rural residential development. Haven Lake Drive extends along the north side of
the property, and Haven Lake is over 300 feet beyond. Vegetation on and near the property
consists primarily of 2nd growth firs, rhododendrons, huckleberry, 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 Project is situated within and near moderate sloping terrain. 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 Map in Appendix A
for an illustration of the general slope indicators with respect to the planned development.
Except for driveway embankments and cut slopes of less than 10 feet high, maximum slope
grades on the property and within 300 feet of the Project were measured to be 25%. This slope is
located primarily to the north of the proposed home site on the descending slope.
2.3 Surface Drainage
The majority of the stormwater runoff originating upslope from the anticipated development is
expected to be minimal to moderate. Significant scour, erosion and sediment transport was not
apparent near the Project.
2.3.1 Upland Water Bodies and Geomorphology
There were no major water bodies or wetlands located upslope from the Project. This is
based on observations during the site visit, and project research.
The property is basically situated on a hillside with about 20 feet in vertical height south
of the property, and 30 to 40 feet to the north of the property.
2.4 Slope and Erosion Observations
The existing moderate slopes near the Project signal a potential landslide or erosion hazard area.
Some indicators that may suggest past slope movements include:
Envirotech Engineering Giese Geological Assessment
Ph. 360-275-9374 page 3 Parcel 22330 50 00300
Fax: 360-275-4789 Mason County, Washington
December 9,2010
• Outwash of sediments near the bottom of the slope,
• Fissures, tension cracks or naturally 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.
The above mentioned indicators, or other signs of significant mass wasting on the property or
within the general vicinity of the Project were not observed or discovered during research.
Indications of past landslides, current unstable slopes, deep-seated slope problems, or surficial
slope failures were not observed during the site visit.
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Soil Survey From USDA Natural Resources Conservation Service
Envirotech Engineering Giese Geological Assessment
Ph 360-275-9374 page 4 Parcel 22330 50 00300
Fax:360-275-4789 Mason County,Washington
December 9,2010
3.0 SUBSURFACE INVESTIGATION
Information on subsurface conditions pertaining to the Project was gathered during research and a
site reconnaissance. The site visit was accomplished on November 19, and November 29, 2010
by Michael Staten,geotechnical engineer with Envirotech. Specific information on field methods,
sampling, field testing, subsurface conditions, and results from soil testing are presented in this
section of the report. Appendix B has pertinent information on subsurface conditions for the
Project, including test pit log(s) representative of the site soils, and water well report(s)
originating from the subject property and/or nearby properties.
3.1 Field Methods,Sampling and Field Testing
Information on subsurface conditions for the Project was accomplished by observing soils within
test pit excavations of up to approximately 4 feet below the existing ground surface, and cut
banks of up to about 8 feet. Information on subsurface conditions also included reviewing
geological maps within the Project vicinity, and water well reports originating from nearby
properties. No soil samples were collected for this Project.
Envirotech measured the relative density of the in-situ soils by gauging the resistance of hand
tools. Field testing results generally indicated loose to medium dense soils in the upper 48 inches,
and very dense soils from 48 inches below the ground surface to the depth of terminous.
3.2 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.
According to the "Geologic Map of the Lake Wooten 7.5-minute Quadrangle, Mason County,
Washington"by Robert E. Derkey,Nicholas J. Hehemann, and Katelin Alldritt, 2009,this Project
consists of Glacial Till. Glacial till is usually described as:
"unsorted, unstratified, highly compacted mixture of clay, silt, sand, gravel, and boulders
deposited by glacial ice of the Puget lobe; gray; may contain interbedded stratified silt, and
gravel; sand-size fraction is very angular and contains abundant polycrystalline quartz, which
distinguishes this unit from alpine till; cobbles and boulders are commonly striated and (or)
faceted; although unweathered almost everywhere, may contain cobbles or small boulders of
deeply weathered granitic rock."
3.3 Specific Subsurface Conditions
The following subsurface conditions are estimated descriptions of the Project subgrade utilizing
Envirotech Engineering Giese Geological Assessment
Ph. 360-275-9374 page 5 Parcel 22330 50 00300
Fax: 360-275-4789 Mason County, Washington
December 9,2010
information from the depth of penetration at all testing, sampling, observed and investigated
locations. Soils for this project were described utilizing the Unified Soil Classification System
(USCS). Using the USCS in conjunction with estimated relative densities and other anticipated
engineering properties of the soil, susceptibility for potential landslides, erosion and seismic
hazards may be assessed.
The Project is composed of fill over native, undisturbed soils. Competent bearing soils were
encountered at 30 inches below the existing ground surface in one location that is expected to
consist of the deepest fill. For engineering purposes, the native soils consist of distinguishable
layers, as presented below.
Soils within the upper 4 feet of natural ground were observed to be moist, brown silty sand with
gravel(SM).
Soils below the upper 4 feet layer were observed to be very dense hardpan. The hardpan is
expected to extend to depths greater than 75 feet. This is based on nearby well reports, site
geology, and/or knowledge of the general area.
The relative densities of the soil 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 upland site soils are described as Alderwood gravelly
sandy loam,Ab,with 5%- 15%slopes.
3.3.1 Groundwater
From the water well report, permanent groundwater is expected to be approximately 100
feet directly below the property near the building pad location. Seepage or other perched
groundwater at shallow depths (less than 50 feet) was not observed on site or recorded in
the water well reports.
3.4 Soils Testing
Laboratory testing of soil samples were not performed for this Project. Visual classification of
soils was performed in the field. The following soil tests were performed in accordance with the
American Standards for Testing and Materials(ASTM):
2 Visual Classifications(ASTM D2488)
3.4.1 Visual Classification
The general results from the visual classification are presented above in the Subsurface
Conditions Section. Specifically, soils within the upper 4 feet in the testing location
consisted of approximately 15% gravel, 70% sand-sized soils, and 15% low plastic silt.
Minor variations observed during the visual classification of particle size content (i.e.
gravel, sand, fines), or isolated pockets within the soil stratification were insignificant in
relation to the overall engineering properties of the soil.
Envirotech Engineering Giese Geological Assessment
Ph. 360-275-9374 page 6 Parcel 22330 50 00300
Fax: 360-275-4789 Mason County,Washington
December 9,2010
4.0 ENGINEERING CONCLUSIONS
The following sections present engineering assessments and conclusions concerning the Project.
These conclusions have been made available based on the planned construction activities as
outlined in the Introduction Section of this report; general observations of drainage and
topography as summarized in the Surface Conditions Section; and, soil conditions that were
identified by the field investigation and soils testing as outlined in the Subsurface Investigation
Section. Conclusions for the Project that is provided herein, includes pertinent information for
landslide, erosion and seismic hazards.
4.1 Landslide Hazards
For the planned development, as provided in the Introduction Section, surface and subsurface
conditions as presented in this report, it is Envirotech's opinion that the proposed development is
not subjected to or cause adverse impacts to a landslide hazard area or its associated buffer or
setback as defined in the MCRO.
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. 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.
Maintenance of the slope should be completed if the situation does arise in order to prevent the
possibility of further surficial or deep seated slope movements that may be damaging to life or
property.
According to the Resource Map from the Washington State Department of Natural Resources
(DNR), the Project is not within terrain labeled `highly unstable' or `highly erodible' relating to
soils. In addition, DNR did not indicated previous landslide activity near the Project. 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 DNR is provided below:
Envirotech Engineering Giese Geological Assessment
Ph. 360-275-9374 page 7 Parcel 22330 50 00300
Fax: 360-275-4789 Mason County, Washington
December 9,2010
1 =
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4.1.1 Landslides and Slope Stability Analysis
Past landslide activity near the proposed development was not revealed during the Project
research. In addition, detrimental landslide activity or potential high landslide indicators
were not observed during the site visit as outlined in the Surface Conditions Section of
this report. Therefore, a slope stability analysis was not deemed necessary for this
Project. Considering the planned construction as summarized in the Introduction Section
of this report; surface and subsurface conditions for the Project; and, the slope stability
assessment provided herein, it is our opinion that the proposed site alterations will not
encourage a landslide hazard.
Envirotech Engineering Giese Geological Assessment
Ph. 360-275-9374 page 8 Parcel 22330 50 00300
Fax: 360-275-4789 Mason County,Washington
December 9,2010
4.1.2 Septic Drainfield Impacts
The approximate locations of the existing septic drainfield are presented on the Site Plan
in Appendix A of this report. The drainfield is not expected to adversely influence
moderate slopes within the vicinity of the septic components. This determination is partly
based on the behavior and characteristics of the Project soils under saturated conditions,
in addition to the relatively moderate grades located immediately upslope and downslope
from the septic drainfield location.
4.1.3 Surface and Subsurface Drainage
This project does not appear to experience significant subsurface drainage or surface
runoff. It is our opinion that groundwater or surface drainage is not a limiting factor for
this Project. However, all drainage facilities should have a protected outlet located at
least 10 feet downslope from all building structures.
4.1.4 On-Site and Off-Site Impacts
From a geotechnical perspective, it is Envirotech's opinion that the Project and adjacent
properties, both upslope and downslope from the planned site alterations should not be
negatively impacted. Existing stable slopes, standard stormwater mitigation, and
anticipated post-development stable slopes does not warrant on-site or off-site concerns.
4.2 Erosion Hazards
Based on the USCS description of the Project soils, the upper soils are considered to have a
moderate erodibility factor. Temporary and/ or permanent erosion control measures may be
required for any site when land disturbance is involved. 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 conditions and planned disturbance of this
Project include wind-borne silts during dry weather,and sediment transport during prolonged wet
weather. Sediment transport of disturbed soils could be from stormwater runoff or tracking off-
site with construction equipment. Temporary erosion control measures may need to be employed
if excessive erosion occurs or required by the County or other prevailing agencies. Permanent
erosion control should include typical best management practices such as protected drainage
outlets and vegetating denuded areas.
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.
4.3 Seismic Hazards
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.
Envirotech Engineering Giese Geological Assessment
Ph. 360-275-9374 page 9 Parcel 22330 50 00300
Fax: 360-275-4789 Mason County, Washington
December 9, 2010
There are no known faults beneath this Project. The nearest Class `A' or'B' fault to this property
is the Hood Canal Fault Zone. This fault is a Class `B,` and is located approximately 5 miles to
the west of the Project. This information is supported by the USGS Quaternary Fault and Fold
Database for the United States.
The potential for liquefaction and other earthquake induced hazards are believed to be low for
this Project. This is based on subsurface conditions such as soil characteristics and the lack of a
permanent and substantial shallow water table. Subgrade characteristics that particularly
contribute to problems caused by seismic events include submerged and confined, poorly-graded
granular soils. Although gravel- and silt-sized soil particles could be problematic, fine and
medium grained sands are typically subjected to these types of seismic hazards.
4.4 Other Considerations
Conclusions in this report are based on the type and location of the anticipated development, and
existing surface and subsurface conditions. Site development that significantly deviates from the
anticipated improvements presented in this report may require geotechnical design
recommendations.
Competent bearing soils beneath the fill are believed to be a maximum of 30 inches below the
existing ground surface, and are probably less in other areas depending on footing locations. It is
imperative that all footings are bearing on undisturbed native soils.
Envirotech Engineering Giese Geological Assessment
Ph. 360-275-9374 page 10 Parcel 22330 50 00300
Fax: 360-275-4789 Mason County,Washington
December 9,2010
5.0 CLOSURE
Based on the project information 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. Therefore, it is recommended that a
qualified engineer observes and documents the construction, or Envirotech is promptly notified if
project and subsurface conditions found on-site are not as presented in this report so that we can
re-evaluate our recommendations.
This report presents a geological/geotechnical assessment, and is intended only for the owner, or
owners' representative. Furthermore, this report is only valid for the project information and
location described herein.
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
/i���!7i
Michael Staten, P.E.
Geotechnical Engineer
Envirotech Engineering Giese Geological Assessment
Ph. 360-275-9374 page 11 Parcel 22330 50 00300
Fax: 360-275-4789 Mason County,Washington
December 9,2010
APPENDIX A
SITE PLAN
SCALE, I INCH = 50 FEET
0
�PJ 3
Ft i
PRIMARY AND
RESERVE SEPTIC
DRAINFIELD
PROPERTY LINE
rIPA
C
d,P
rL
91,
�s.
,X
PROPOSED
SINGLE
TP FAMILY
RESIDENCE
PROJECT/ OWNER/ LOCATION,
H❑LMES
GE❑L❑GICAL ASSESSMENT
KEN GIESE
PARCEL NO 22330 50 00300
MASON COUNTY, WASHDVGTON
ENGINEER,
LEGEND ENVIROTECH ENGINEERING
74 NE HURD ROAD
2/,t SLOPE INDICATOR BELFAIR, WASHINGTON 99528
V 360-275-9374
TPI e TEST PIT
SITE PLAN
APPENDIX B
SOIL INFORMATION
TEST PIT LOG
TEST PIT NUMBER TP-1
PROJECT: SFR Geological Assessment DATE OF LOG: 11/29/2010
PROJECT NO: 10123 LOGGED BY: MCS
CLIENT: Ken Giese EXCAVATOR: N/A
LOCATION: Parcel 22330 50 00300 DRILL RIG: None
Mason County, Washington ELEVATION: N/A
INITIAL DEPTH OF WATER: N/A FINAL DEPTH OF WATER: NIA
SOIL STRATA, STANDARD PENETRATION TEST
DEPTH SAMPLERS USCS DESCRIPTION LL PI CURVE
AND TEST DATA DEPTH N 10 30 50
0 . ........................I............ .............
FILL
1 . ................ ...... ..... . ......................
SM Brown, moist, medium dense SILTY
SAND with GRAVEL. Gravel is
well-graded and subrounded. Sand is
2 primarily coarse. None to low plasticity.
3
Very dense grey'hardpan.' Decreasing
gravel. Increasing fine and med sand.
4 Excavation terminated at approximately
4.0 feet
5
6
7
8
9
10
No Groundwater Encountered ENVIROTECH ENGINEERING
This in/ornmHon pertains only to this boring and should not be Geotechnical Engineering
interpreted as being indicitive o/the entire site.
L
O
CL
QI
WATER WELL REPORT CURRENT
Notice of Intent No. wE04269
Orlglaal&1"copy—Ecology,ze°copy—owner,3r°rnPY—dn7ltr
? e c o i e s r Unique Ecology Well ID Tag No. APM584
H Construction/Decommission ("x"in circle)
❑� Construction Water Right Permit No.
+-� Decommission ORIGINAL INSTALLATION Notice Property Owner Name CRAIG JOHNSON
C of Intent Number 210 NE RAVEN LAKE DR
p Well Street Address
C PROPOSED USE: Domestic ❑ Industrial ❑ Municipal City BELFAIR County MASON
O ❑DeWater Irrigation ❑Test Well ❑Other
Location NE 1/4-1/4 SW1/4 Sec 30 Twn 23 R2W FWM ❑ci ek
TYPE OF WORK: Owner's number of well(if more than one) «
WWM M one
E m New well ❑Reconditioned Method:❑Dug ❑Bored ❑Dnven Lat/Lon S,t,r Lat Deg_ Lat Min/Sec
i ❑Deepened [:I Cable m Rotary ❑Jetted g(
- DIMENSIONS: Diameter of well 6 inches,drilled 257 ft. Stull REQUIRED) Long Deg Long Min/Sec
Depth of completed well 256.3 ft.
CONSTRUCTION DETAILS Tax Parcel No. 223305000301
S Casing 0 Welded 6 Dism fmm 0 ft.to 251 IL
Installed: B Liner installed Diam,from ft.to ft. CONSTRUCTION OR DECOMMISSION PROCEDURE
L Threaded Diam.from ft.to R
Perforations: Yu o ---_ _— Formation: Describe by color,character,stzr of matenal and slnrcNre,and the kind and
__ _ nature of the material m each stratum penetrated,with at least one entry.for each change of--
_ Typeofperforatorused information. SE ADDITIONAL SHEETS IF NECESSARY.
SIZE of perfs in.by in.and no.of perfa_from_ft to ft. MATERIAL FROM TO
Screens: m Yes ❑No m K-Pac Location 251 PIPE STICK UP 0 1
{a Manufacturer's Name JOHNSON BROWN SAND GRAVEL CLAY t 26
t0
Q Type SS WELD ON Model No, TELESCOPING GRAYISH BROWN SAND GRAVEL CLAY 26 102
Diam,6 Slot sir 20 from 251 ft,to 256.3 ft-
Diam.—Slot size from ft.to ft. BROWN CLAY WET 102 Hs
46J Gravel/Fliter packed:0 Yes ONo ❑Size of gnveVsand BROWN SAND GRAVEL SOME WATER 115 121
Materials placed from ft to fi BROWN GRAVEL SAND CLAY 121 153
SarfaceSeaboYes ❑No Towhatdcpth? 18 ft. BROWN GRAVEL SAND CLAY WET 153 173
M Material used in seal RFNTONITE BROWN GRAVEL SAND CLAY 173 250
L Did my strata contain unusable water? ❑Yes m No BROWN SAND GRAVEL WATER 250 257
SType of water? Depth of strata
S Method of sealing strata off
PUMP: Manufacturer's Name
OType: H.P.
Z WATER LEVELS: Land-surface elevation above mean sea level ft.
d) Static level 223 ft.below top of well Date-1 1/09105
0 Artesian pressure Ibs.per square inch Date
Artesian water is controlled by
,valve etc.
aI WELL T—STS: Drawdown is amount water level is lowered below static level
G Was a pump test nude?❑Yes m No If yes,by whom?
O Yield: pal./min,with L drawdown after firs.
0 Yield: RalJmin.with ft drawdown aticr his.
I
Yield. Ral./min.with ft.drawdown after firs.
- Recovery data(time token ate zem when pump turned oJn(voter level measured from well
top to water level) J
Time Water Level Time Water Level Time Water Level
015
L Date of testev `r
Q Bailer test 12 galJmin.with 2 ft.drawdown after I l rs. ()
Airtcst gal./min.with stem set at ft.for firs.
Artesian flow R-P.m. Date
Temperature of water Was a chemical analysis made? ❑Yes ®No
Start Date 11/04/05 Completed Date 11/09/05
WELL CONSTRUCTION CERTIFICATION: I constructed and/or accept responsibility for construction of this well,and its compliance with all
Washington well construction standards. Materials used and the information reported above are true to my best knowledge and belief.
❑Driller ❑Engineer❑Trainee Name rim)JOHN ULLIVAN Drilling Company NICHOLSON DRILLING INC
Driller/E a agmeer/rraia Signature ___ Address 1O BOX 123
Driller or traince License No.2218 City,State,Zip PORT ORCHARD,WA 98366
If TRAINEE, Contractor's
DrlRer's Licensed No. Registration No. NICHODI1370M
DrWer's Sipature Ecology is an Equal Opportunity Employer.
ECY 050-1-20(Rev 3/05) The Department of Ecology does NOT warranty the Data and/or Information on this Well Report.
Flier°"g`"'and
ollimCopy"''"' stem Card No. 075720
o.paftnlent of Eeology WATER WELL REPORT fNQUEWELLI.D.a AC-1 963
second Copy-owner's Copy STATE OF WASHINGTON
Third Copy-DdlWa Copy Water Right Permit ND. -- -- --
0 (1) OWNER: Nam,-Bob Curtis Address 8414 Caraway Rd. Port Orchard, WA 98366
o.
0 (2) LOCATIONOF WELL: coney Mason LNE
(2n) S1WET ADDRESS OF WELL(or neerem ad drew NE 251 Havpn Lk Dr T ht tryr3. WA 98 588
Domestic 10 WELL LOG or ABANDONMENT PROCEDURE DESCREMON
(3} PROPOSED USE: � Industrial f 1 Municipal ❑ ( )
E Irrigation Test Well L) Orler ❑ Fomtatlon:Downbe by color.character.size of materUi and stnrcrure.and show thidmess of equiers
to C DeWater and the Mid and nature of the material n each strobe peneeated.with at Mast one array for each
S (4) TYPE OF WORK: teener'.number of waif rJ+vnpe of nformabon.
(9 mms then one) MATERIAL r"M To
Abandoned❑ New well OC Method:Dug❑ Bored❑ --
O Deepened ❑ Cable B Driven[]
0 Reconditioned❑ Rotary❑ Jetted❑ Brown grmTl hardpgn 0 190
O
(S) DIMENSIONS: Diameterofwell 6 itctea.
Drilled 202 -feet. Depthof completed well 202 11. Sand & ravel with water 190 202
00 (6) CONSTRUCTION DETAILS:
"' CaskV kgWled: 6 Diem from_0 to 197 tL
Welded N Dian.hum h.fo IL
Liner Installed❑
S Threaded ❑ Diem.from fL W IL
L Perfontlonc Yea❑ No
O Type of pedorator used
a SIZE of perforations in.by- -_----In-
_ perfwab"from n.to fL
perforations from rt.to fir. r
r perMaors il from
Ri >�n
screens: Yes ER No❑
fy Manutac"W's Nam. Cook -
+S-n Typa stainless wire wren Model No. zp
2. �.
Diem. -5__Slot an 20 to 2Q7 ft. — - --
C Dian. _Siot 0ae _from it.to rt.
L Caravel Pat:ltad: Yes❑ No® Size of gravel
Gravel paned from rt.to_ ft. -
SLrfaDaMM: Yes® No❑ To what depths is h.
O Material used in afral - --
Z Did any strata contain unusable walar? Yes❑ No❑
f A Type of water? Depth of strata
41 lsethod or sealing it. off
(7) PUMP: Manufacturer's Name 1fIMYAL Jacuzzi
Type: Sl1I? H.P. - -
O (8) WATER LEVELS:
"m��� n Work stared 5/�f 97 .,s comdated_ 5/26/97 .to
O Sutic level__11_Sl _ fi belay top ofwdi Date V Anesain pressure Ibs per square nch oaro WELL CONSTRUCTOR CERTIFICATION:
W
w Anawnwanrisconlr~try _. _. _ _. _- ._ I constructed and/or accept responsibility, for construction of this well, and its
O compliance with all Yyashrngton well construction standards.Materials used and
+a (9) WELL TESTS: Drawdown is amour water level is lowered below static Navel the Information reported above are true to my best knowledge and 6ef et
C
Wee a pump Met made?Yee❑ No ER If yes.by whom? NAME Davis Drilling
at./tan.with--- _n.drawdown anef Irf. (PERSON.FPIa On Tprrl rrrPE oa PROM Ymid' g
a.n f"' " •• •• •• Address Belfair WA 98528
CL
41 Recovery data(time taken as zero when pump tumed of)(wafer level measured from well
{Signed) License No. 1773
Q lop No weter level)
Time Water Level tone Water Laval Rime Wafer level Cordrector'a
►- _-- _-- _ - --- --_ - No. V�nDAVISDI1100A _ Date-_ May 19_2Z
(USE ADDITIONAL SHEETS IF NECESSARY)
Dam of last
saisr test 15 oN.lmin.with 12 R.bawdoww ablerhn-
Arfeet_gal I min with scam eat at it.br f,,,- Ecology is an Equal Opportunity and Affirmative Action employer.For spe-
Artiaion nit+ g.p.m. Data eel accommodation needs,contact the Water Resources Program at(206)
Temperature of water Wee a chemical analysis made? Yee❑ No® 407-6600.The TDD number is(206)407-6006-
ECY DW1-20 MM)--f