HomeMy WebLinkAboutGEO2015-00036 for BLD2015-00691 - BLD Engineering / Geo-tech Reports - 9/14/2015 MASON COUNTY
DEPARTMENT OF COMMUNITY DEVELOPMENT
Planning Division
P O Box 279, Shelton,WA 98584
(360)427-9670
Geotechnical ReportReview Acceptance Letter
September 14, 2015
CHARLES VANDEVER
P O BOX 381
UNION WA 98592
Case No.: GE02015-00036
Parcel No.: 322353100170
Proiect Description: GEO REPORT REVISION & ADENDUM (SEE BLD2015-00691)
The Geotechnical Report for CHARLES VANDEVER has been received and reviewed by the
Planning Department. The report was prepared by Michael Staten PE 43045 dated 4/3/2008.
Based on the certification provided by the licensed engineer/geologist, the referenced
Geotechnical Report was prepared in general accordance with the requirements in the Mason
County Resource Ordinance, Landslide Hazard Areas 17.01.100.E.5. Mason County considers the
review valid until such time as scope of project, site conditions, and/or regulations change. Should
the scope of work, site conditions, and/or regulations change after the original review, then an
addendum from the original author of the report may be required to address these changes. The
report would only be re-reviewed if a permit for development were submitted after these changes
occur. Mason County does not certify the quality of the work done in this Geotechnical Report.
Please contact me at (360) 427-9670, ext. 365 if you have questions.
Sincerely,
h4�
Allan Borden
Land Use Planner
Mason County Planning Department
Comments:
9/14/2015 Page 1 of 1 GE02015-00036
Envirotech Engineering
74 NE Hurd Road,
Belfair, WA 98528
April 3, 2008
Rick Buechel
South Shore Enterprises, LLC
PO Box 249
Union, Washington 98592
RE: Geotechnical Report for Three Single Family Residences, Parcel Numbers
32235 31 00150, 32235 3100160 and 32235 31 00170, Mason County, Washington,
Addendum#2
INTORDUCTION
Envirotech Engineering (Envirotech) has completed this second geotechnical addendum
for the above referenced "Geotechnical Report for Three Single Family Residences..."
The original report was submitted November 28, 2007 by Envirotech (Project #0759),
with a subsequent addendum on February 28, 2008. This addendum was prepared in order
to provide additional information concerning the project and the geotechnical report. The
following sections include Site Characteristics; Evaluation and Analysis; and,
Recommendations and Design Criteria that correspond to comments received from Keneth
Neal& Associates that was mailed by Mason County in a letter dated March 26, 2008.
SITE CHARACTERISTICS
The proposed residence on Lot 160 is located within the flood path of a small stream. The
top of ground at the planned residence is well above the ordinary high water mark (in
contrary to addendum #1), and below the maximum possible water level. Several
residences along Hood Canal are located within flood paths of both larger streams and
convergences where the water flows only a portion of the year. As a result, many homes
and property are damaged by flooding with water and outwash during excessive storm
events such as that experienced in December 2007. This implies that the proposed
residence or property could be damaged due to impending flooding. The recent storm
exceeding the 100yr, 24-hr rainfall event did not cause major concern to the existing
residence on Lot 160. However, successive flooding events may present different results.
Furthermore, the upslope drainage pattern from this residence indicates that the stream
could naturally change coarse over time, and will most likely be directed towards the
development on Lot 160. Predicting and quantifying these hazards are unfeasible, and it is
Envirotech Engineering Geotechnical Addendum#2
Ph. 60-275 937-4 Page 1 of 3 Three Singlc Family Residence
Fax 360-275-4789 Lot 150. Lot 160& Lot 170
April 3. 2008
possible that the development could remain unscathed for its entire design life.
Streambank control such as riprap and concrete revetment walls, as previously
recommended in the geotechnical report, that are constructed on or beyond the east bank
of the stream are typical erosion prevention and stream control. These types of controls, if
properly maintained, have proven to be successful in the past. However, a guaranteed type
of stream control is not possible, and could be rendered useless at anytime during its
design life by extreme flooding and debris flow.
The fine subgrade soils as previously described in the original geotechnical report, and
indicated on the water well report in the ensuing appendix of the geotechnical report was
not properly shown on the soil profile. This soil strata is shown in the revised soil profile
attached to this addendum.
EVALUATION AND ANALYSIS
The original slope stability analysis for this project was completed utilizing a spreadsheet
iterative approach. This method is basically hand calculations from the simplified Bishop
method using 10 slices. For Addendum #1, 'STABLE' software was used for the same
slope stability analysis. This software automatically selects various centers and radii with
over 100 slices, and subsequently numerous slip planes are estimated for factors of safety
from the geometry specified. Initiation points vary, and are located within the extents of
the geometry specified. Depending on the specific location of the center and the length of
radius, the initiation point includes numerous points from 50 feet beyond the top of the
slope, the slope face, and 50 feet beyond the slope toe. Factors of safety are similar for
both the STABLE software and hand calculations.
The fine soils as indicated on the well report are far below any potential slip planes for this
project. The fine soils were conservatively shown to be closer to the ground surface near
the toe of the steep slope. A slope analysis with the finer soils is provided as an attachment
to this addendum. Extremely conservative strength parameters were used for this analysis.
These parameters include 400 psf cohesion, 0 angle of internal friction and a unit weight
of 120 pcf.
RECOMMENDATIONS AND DESIGN CRITERIA
Native soils may be used as fill material per the recommendations that are outlined in the
geotechnical. re Si
P y report. Alternatively, engineered fill may also be used for both building and
road foundations. These soils will perform appropriately if the fill placement and
compaction recommendations are followed per the geotechnical report. For soils used as
fill, it is suggested that they are protected from wet weather by appropriate means and
En irolech Engineering Gcotechnical Addendum #2
Pli. 360-275 9374 Page 2 of 3 Thrce Single Family Residence
Fax 360-275-4789 Lot 150. Lot 160& Lot 170
April 3. 2008
methods in order to reduce the potential for soil saturation. Although these soils are not
extremely susceptible to wet weather, saturated conditions could cause extra time and
delay during development.
General cross sections of the proposed driveway to Lot 170 is depicted as an attachment
with general notes. The proposed driveway consists of about 150 feet of
to this addendumP P
g
new driveway, and approximately 100 feet of new driveway in the same location of an
existing driveway. The geotechnical report provides a pavement structural section,
stability of cut slopes and embankments, and general erosion control recommendations.
General surface water management is also provided. In addition, catch basins or speed
bumps could be utilized in order to manage stormwater and prevent rapid runoff from
leaving the paved areas. Current Mason County regulations will require a stormwater
management plan to address the water quality and quantity of the roof and driveway due
to the amount of impervious surfaces on Lot 170. In addition extensive temporary and
permanent erosion control will also be required in conjunction with the stormwater
management plan. It is recommended that a qualified professional specializing in
geotechnical engineering reviews the stormwater management plan to assure that the final
drainage design complies with the geotechnical expectations for this project.
CONSLUSION
Envirotech is pleased to submit this addendum for the Buechel single family residential
lots. Please contact Michael Staten at 360-275-9374 if you have any questions, comments,
or require additional information.
Best Regards,
Envirotech eering
wAs,��T9
0
`sI�NAL
to,
Michael Staten, P.E.
Project Manager
Envirotech Engineering Geotechnical Addendum#2
Ph. 360-275 9,74 Page 3 of 3 Three Single Famihv Residence
Fax 360-275-4789 Lot 150. Lot 160& Lot 170
April 3. 2008
ATTACHMENTS
1. GEOLOGIC MAP
2. SOIL PROFILE
3. SLOPE STABILITY
4. ROAD CROSS-SECTIONS
5. KENNETH NEAL&ASSOCIATES REVIEW COMMENTS
CREEK PROPERTY LINE SCALES 1 INCH 60 FEET
LOT 150 LOT 160 LOT 170
A
OPOSED DRAIhFIELD F
OPTIONAL DRAINAGE OUTFAL
(V
SLIGHTLY PROP13SED HOME (TYP)
SLOPIN
P
S�"QO P�9
1`\ VJu
O
EXISTING SF /FPOSS
SKIDDER F OAD 3jQO�G��
mi DRIVEWAY
G O
�o SLOPE T
P�
100 �f S OPTIONAL DRAINAGE
1 TFALL
EXISTING T`r
ROAD
BO RELATIVE
FLAT
BEGINNING
PROPOSED D EWAY
60 ` S R
A
,9FR 6 GNP
1
40PZNP 6
5jpc- SOILS, MEDIUM DENSE TO DENSE POORLY
GRADED SAND WITH SILT AND GRAVEL
CSP-SM> OVERLYING VERY DENSE TILL
Q G
HOOD CANAL
NSF'
20 $
PROJECT/ OWNER/ LOCATIONi
THREE LOT
GEOTECHNICAL REPORT
BUECHEL AND TEMPLEMAN
PARCEL 32235 31 00130, -160, S -170
NOTES- LEGEND MASON COUNTY, WASHINGTON
1. CONTOURS ARE MOT PRECISE, AND ONLY DEPICT GENERAL
TOPOGRAPHIC CONDITIONS. CONTOURS WERE EXTRAPOLATED ENGINEER-
FROM A PUBLIC LIDAR SOURCE, AND INCORPORATED FIELD BUFFER ENVIROTECH ENGINEERING
MEASUREMENTS. SLOPE DIRECTION 74 NE HURD ROAD
2. VEGETATION SHALL NOT BE REMOVED UPLSOPE FROM LOT BELFAIR, WASHINGTON 98528
150 AND 160 UNLESS HAZARDOUS VEGETATION BUFFER IS 8D EXISTING CONTOUR 360-275-9374
LOCATED ON
H RIDGE .OR LOT 170 WITH EXCEPTIONS AS
OUTLINED THE GEOLOGIC MAP
MEDIUM DENSE TO DENSE POSSIBLE RIDGE PROPOSED HOUSE SCALE. I INCH 60 FEET
POORLY GRADED SAND WITH REMOVAL CREEK EXISTING GRADE
SILT AND GRAVEL (SP-SM) u
HIGHWAY 106
IOFT BANK 4:t DENSE TO VERY
56FT
DENSE SILTY SAND
HOOD CANAL AND GRAVEL
- - - - - - - - - - - - - - CLAY OR SILTY- - - - - - - - - - - - 15FT
- - - CLAY - - - - - - - - - - - - -
SECTION A-A
MEDIUM DENSE TO DENSE
POORLY GRADED SAND WITH EXISTING GRADE
SILT AND GRAVEL (SP-SM)
65%, 12FT SLOPE
PROPOSED HOUSE
NOTES. HIGHWAY 106
1) EXCEPT FOR POSSIBLE RIDGE REMOVAL ON LOT 1OFT BANK DENSE TO VERY
170, MINIMAL GRADE CHANGES ARE EXPECTED
DUE TO BUILDINGS FOUNDED ON NEARLY FLAT TO HOOD CANAL DENSE SILTY SAND
SLIGHTLY SLOPING SURFACES. LIGHT GRADING AND GRAVEL
WILL BE REQUIRED TO ACHIEVE POSITIVE
DRAINAGE FROM BUILDINGS.
LAY OR SILTY CLAY - -
SECTION B-B
EXISTING GRADE
MEDIUM DENSE TO DENSE
POORLY GRADED SAND WITH
SILT AND GRAVEL (SP-SM)
65%, 6FT SLOPE `^
PROPOSED HOUSE
g%t
HIGHWAY 106 G�
LOFT BANK
DENSE TO VERY PROJECT/ OWNER/ LOCATION•
HOOD CANAL DENSE SILTY SAND THREE LOT
AND GRAVEL GE❑TECHNICAL REPORT
BUECHEL AND TEMPLEMAN
_ _ _ _CLAY OR SILTY CLAY_ _ _ _ _ _ _ _ _ _ PARCEL 32235 31 00150, -160, R -170
- - - - - - - - - MASON COUNTY, WASHINGTON
SECTION C-C ENGINEER,
ENVIROTECH ENGINEERING
74 NE HURD ROAD
BELFAIR, WASHINGTON 98528
360-275-9374
S❑IL PR❑FILE
1 . 00
1 . 10
1 . 20
1 . 30
1 . 40
1 . 50
i 1 . 60
1 . 70
1 . 80
1 . 90
2 . 00
791
Project Buechel
Datafile Lot 1 70 downslope revised
Analysis Bishop
STABLE.2002 MZ Associotes Ltd
2' ASPHALT CONCRETE OVER 6' BASE COARSE
95% COMPACTION (SEE REPORT)
271 MIN STRUCTURAL FILL 95% COMPACTION
(SEE REPORT)
ORIGINAL GRADE 2
1 CREEK �,-
NOTES,
THIS SEGMENT IS ESTIMATED TO HAVE
PREPARED SUBGRADE GRADES OF 5%. EXCAVATION IS
(SEE REPORT) REQUIRED ONLY TO REMOVE
DELETERIOUS MATERIAL ON THE
SURFACE. THIS SEGMENT CONSISTS OF
EMBANKMENT ONLY. DRAINAGE SHALL
BE DIVERTED AWAY FROM THE CREEK.
rnW&L ROAD CRM SEC MN FROM STA Oi00 OMY 106)TO STA.1+10(110 7)
NOT TO SCALE
ORIGINAL GRADE
2' ASPHALT CONCRETE OVER 6' BASE COARSE
95% COMPACTION (SEE REPORT)
10FT MAX 21 MAX
2% MIN ct CREEK�
NOTES-
2 THIS SEGMENT IS ESTIMATED TO HAVE
GRADES OF 23%, AND IS PRIMARILY A
FULL BENCH CUT. CUT SLOPE HEIGHT
SHOULD NOT EXCEED 10 FEET.
RETAINING WALLS ON THE UPSLOPE
PREPARED SUBGRADE SIDE OF THE ROAD MAY BE UTILIZED
(SEE REPORT) TO REDUCE CUT SLOPES. DRAINAGE
SHALL BE DIVERTED AWAY FROM THE
CREEK.
TYPICAL ROAD CROSS WCIION STA.1+10 TO 9TA.1+50(30yI)
NOT TO SCALE
2' ASPHALT CONCRETE OVER 6' BASE COARSE
95% COMPACTION (SEE REPORT)
2X MIN L STRUCTURAL FILL 95% COMPACTION
(SEE REPORT)
ORIGINAL GRADE 1 CREEK-�
NOTES
THIS SEGMENT IS ESTIMATED TO HAVE
GRADES OF 23%. EXCAVATION IS
PREPARED SUBGRADE REQUIRED ONLY TO REMOVE
(SEE REPORT) DELETERIOUS MATERIAL ON THE
SURFACE OR ACHIEVE APPROPRIATE
ELEVATION. THIS SEGMENT CONSISTS
OF EMBANKMENT ONLY, DRAINAGE
SHALL BE DIVERTED AWAY FROM THE
CREEK.
TYPICAL ROAD CROSS SECTION FROM STA 14-S L _ __,T0STAl#40(-llWn
NOT TO SCALE
PROJECT/ OWNER/ LOCATION,
THREE LOT
GE❑TECHNICAL REPORT
GENERAL NOTES BUECHEL AND TEMPLEMAN
1. ROAD WIDTHS AND GRADES SHALL BE IN PARCEL 32235 31 S R -170
ACCORDANCE WITH PREVAILING GOVERNMENT MASON COUNTY, WASHINHINGTOONN
STANDARDS OR VARIANCES.
2. MATERIALS, PLACEMENT AND COMPACTION SHALL ENGINEER,
BE IN ACCORDANCE WITH THE WASHINGTON STATE DOT ENVIROTECH ENGINEERING
STANDARD SPECIFICATIONS. 74 NE HURD ROAD
3. THE PREPARED SUBGRADE SHALL EXTEND AT BELFAIR, WASHINGTON 98528
LEAST 12 IN:HES BELOW THE EXISTING GROUND SURFACE 360-275-9374
AND FOLLOW THE RECOMMENDATIONS AS PROVIDED IN THE
GEOTECHNICAL REPORT. ROAD CR❑SS-SECTI❑N
KENNETH NEAL & ASSOCIATES
CONSULTING ENGINEERING GEOLOGISTS
3314 Gibraltar Ct.S.E.,Olympia,WA 98501-3968 0� Washy
Telephone: (360)352-5125 Fax: (360)236-0201 �e fo
e-mail: kengneal@ffoLcora
March 25,2008
MEMORANDUM
TO: Mason County Department of Community Development
ATTENTION: Robert D.Fink,AICP,Planning Manager
FROM: Kenneth G.Neal,L.G.,L.E.G.,Principal Engineering Geologist KENNETH G. NEAL
SUBJECT: Review Comments—VAR 2008-00002,MEP 2008-00007
"RE: Geotechnical Report for Three Single Family Residenes, Parcel
Numbers 32235 3100150,32235 3100160 and 32235 3100170,Mason County,
Washington, Addendum #1," letter, prepared by Envirotech Engineering for
Rick Buechel of South Shore Enterprises,LLC,dated February 28,2008
The consultant made a concerted effort to address the issues outlined in our February 8, 2008
memorandum. There are, however,a number of unanswered questions that remain:
Issues Related to Site Characteristics:
1. "2.3 Surface Drainage"provides a much-improved description over the previous report. If recent
flooding "produced substantial outwash on the highway," and "less than 1-foot of outwash and
sediments were accumulated adjacent to the(existing) structure," it appears that the stream must
have overtopped the banks in the vicinity of the existing structure. The letter implies that the
lower two building sites are in the flood plain of the stream. Further, the recommendations
outlined in "4.1.3 Concrete Slabs-on-Grade (new paragraph)" indicate that the building sites are
below the ordinary high water mark for the stream and should be protected by some type of
revetment. While this site is not listed by FEMA and, therefore, does not meet the criteria
outlined in Mason County Resource Ordinance(MCRO) 17.01.090, it would not seem prudent to
construct two residences at sites known to be within the flood channel of a small stream.
The one remaining question regarding the stream is whether the channel in which the stream is
currently located is temporary, given that the topography indicates that the current channel is
actually higher than some locations adjacent to the channel to the east.
2. There are a number of questions remaining about geological interpretation at the site. We concur
with the comment in Response 2, that the "Soil characteristics and geological process located
downslope from an area of concern could be similar to the upslope geology." The question is
whether the soil characteristics and geological processes are the same at both locations. The
consultant is responsible to provide a site-specific geological interpretation of the site, and to
present a reliable (if not accurate) portrayal of horizontal and vertical distribution of soil
materials. The well location is now shown on the site plan, but the geology shown on the well
log is not projected into the plane of the section. The cross-sections contained in the addendum
do not reconcile the fine-grained deposit shown on the well log and site characteristics observed
by the consultant. Fine-grained glaciolacustrine deposits are not that uncommon along Hood
Canal. If the depth of the glaciolacustrine deposit shown on the well log is below the depth of
any potential slope movement, then the only remaining question would be the potential for
Mason County Department of Community Development
VAR 2008-00002,MEP 2008-00007
March 25,2008
Page 2
perching of ground water. The information should all be reconciled, and presented clearly on the
cross-sections,which need elevation and horizontal control and a larger portrayal to be helpful.
Issues Related to Evaluations and Analyses:
1. We are unfamiliar with the type of graphics used to portray the slope stability analyses used in
this report. It appears, from looking at the graphics,that all of the analyses extended from the top
of the slope to beyond the base of the slope and the highway. If such is the case,then the factors
of safety(FS)would likely be higher than those that extend only down to the toe of the slope. If
the pie-shaped wedge shown on each graphic represents the actual slope segment analyzed, then
the program likely selected the most sensitive slope for analysis.
2. The position of the glaciolacustrine deposit may influence ground water distribution beneath the
slope. This possibility should be evaluated once the cross-section and well log are reconciled.
Issues Related to Recommendations and Design Criteria
1. Under Item 3, we understand and concur that on-site soils will perform appropriately if soil
moisture contents are within three percent of optimum. Again, there is no contingency plan
described in the report for importing fill material in the event of wet weather construction. Perhaps
the expectation is that, in the event of inclement weather,the construction contractor will spread the
soil and wait for it to air dry prior to use, in lieu of importing structural fill materials having few or
no fines.
2. Questions regarding the driveway remain. In order for the county to be able to assess site
suitability for a variance, in our judgment, there should be a clear plan in terms of location, grade,
and construction method(s). Again,once the location of the driveway is known(based on the grade
needed to access the site),the driveway should be divided into terrain segments, and cuts, fills,and
drainage needs should be at least estimated for each segment. Typical cross-sections for each
segment should be measured and analyzed for stability characteristics following excavation or
filling. Design criteria for cuts, fills, and drainage, both general and segment-specific, should be
provided as part of the report. We also question whether the cross-section shown for the road is
realistic, given that a near-vertical cut slope four or five feet high could be constructed in lieu of
excavating and exposing the entire height of the slope.
Some of these issues could likely be resolved by telephone. Each of the issues should be resolved prior to
acceptance of this report and issuance of a variance and environmental permit.
If you have any questions, please call. I can most easily be reached on my cell phone at 360-280-6180.
2 copies submitted
KENNETH NEAL&ASSOCIATES
CONSULnNC ENGINEERING GEOLOGISTS 3314 Gibraltar Ct.SE,Olympia,Washington 98501-3968 (360)352-5125
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Geotechnical Report
for
Three Single Family Residences
Parcel Numbers 32235 3100150,
32235 3100160 and 32235 3100170
Mason County, Washington
November 28, 2007
Project#0759
Prepared For:
Rick Buechel of
South Shore Enterprises, LLC, &
Mel Templeman CLYD�s
Prepared By:
Envirotech Engineering r f.` i�l2al°-7
74 NE Hurd Road 4304�� v '
Belfair, Washington 98528 AL
Phone: 360-275-9374 �
Fax: 360-275-4789 ocPir�sAl� 10 Zqo
TABLE OF CONTENTS
1.0 INTRODUCTION...........................................................................................................................I
1.1 PROJECT DESCRIPTION................................................................................................................. 1
1.2 PURPOSE OF INVESTIGATION........................................................................................................ 1
1.3 SCOPE OF WORK........................................................................................................................... 1
2.1 GENERAL OBSERVATIONS............................................................................................................3
2.2 TOPOGRAPHY............................................................................................................................... 3
2.2.1 Upslope Geomorphology....................................................................................................... 3
2.2.2 Downslope Geomorphology.................................................................................................. 3
2.3 SURFACE DRAINAGE.....................................................................................................................3
2.4 SLOPE AND EROSION OBSERVATIONS...........................................................................................4
3.0 SUBSURFACE INVESTIGATION.................................................................................................5
3.1 FIELD METHODS........................................................................................................................... 5
3.2 FIELD SAMPLING AND FIELD TESTING..........................................................................................5
3.3 GEOLOGIC CONDITIONS...............................................................................................................5
3.4 SPECIFIC SUBSURFACE CONDITIONS.............................................................................................6
3.4.1 Groundwater......................................................................................................................... 6
3.5 SOILS TESTING.............................................................................................................................6
3.5.1 Visual Classification............................................................................................................. 7
4.1 BUILDING FOUNDATION RECOMMENDATIONS..............................................................................8
4.1.1 Bearing Capacity.................................................................................................................. 8
4.1.2 Settlement.............................................................................................................................8
4.1.3 Concrete Slabs-on-Grade...................................................................................................... 9
4.2 LATERAL EARTH PRESSURES........................................................................................................9
4.3 EARTHWORK CONSTRUCTION RECOMMENDATIONS....................................................................9
4.3.1 Excavation............................................................................................................................ 9
4.3.2 Placement and Compaction of Native Soils and Engineered Fill........................................ 10
4.3.3 Retaining Wall Back/ill....................................................................................................... 10
4.3.4 Wet Weather Considerations............................................................................................... 11
4.4 SLOPE STABILITY AND EROSION CONTROL................................................................................ 11
4.4.1 Septic Drainfield Impacts.................................................................................................... 12
4.4.2 Building and Footing Setbacks........................................................................................... 13
4.4.3 Temporary and Permanent Erosion Control....................................................................... 13
4.4.4 Surface and Subsurface Drainage...................................................................................... 14
4.4.5 Vegetation Considerations.................................................................................................. 14
4.4.6 Off-site impacts................................................................................................................... 15
4.5 SEISMIC CONSIDERATIONS......................................................................................................... 15
4.6 DRIVEWAY CONSIDERATIONS..................................................................................................... 15
4.6.1 Surface Course................................................................................................................... 16
4.6.2 Roadway Earthwork Construction Recommendations........................................................ 17
5.0 CLOSURE..................................................................................................................................... 18
Appendix A- Site Plan
Appendix B -Geologic Map
Appendix C -Soil Information
Soil Profile
Soil Logs
Well Reports
Appendix D- Slope Stability Input&Output
Appendix E-Erosion Control
Appendix F-Drainage Details
Appendix G-Roadway Details
1.0 INTRODUCTION
Envirotech Engineering (Envirotech) has completed a geotechnical investigation for three
adjacent properties identified as parcel numbers 32235 31 00150, 32235 31 00160 and 32235 31
00170 located in Mason County, Washington (Project), This report will refer to these parcels as
Lot 150, Lot 160 and Lot 170, respectively. 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 soils descriptions in the
Subsurface Investigation Section; and, recommendations for foundation, settlement, earthwork,
lateral earth pressures, drainage, slope stability and erosion control in the Engineering Analysis
and Recommendations Section.
An initial geotechnical evaluation of the Project was conducted by Envirotech with one of the
property owners, Rick Buechel of South Shore Enterprises, LLC, on November 1, 2007. It was
determined that slopes in excess of 40% were present within 300 feet of the property, and
subsequently will require a geotechnical report pursuant to landslide hazard areas of the Mason
County Resource Ordinance. During the evaluation and subsequent site visits by Envirotech,
surface and subsurface conditions were assessed. After completion of the field work and
applicable Project research, Envirotech prepared this geotechnical report.
1.1 Project Description
Information pertaining to the Project was provided by the property owners of the Project. The
Project is directly accessed from State Route 106. See the vicinity map on the following page of
this report. Removal of abandoned structures on Lot 150 and Lot 160 will be completed prior to
building the new residences. At a minimum, the new development is expected to consist of 1 or
2-story homes, driveways, and on-site septic features. Construction is expected to consist of a
typical wood frame, with concrete footings, stem walls, and slabs-on-grade. Approximate
building footprints with relation to site features are illustrated in the Site Map in Appendix A.
1.2 Purpose of Investigation
The purpose of this geotechnical investigation was to evaluate the Project in order to provide
geotechnical recommendations relating to the development of the property. The investigation
included characterizing the general Project surface and subsurface conditions, and evaluating the
suitability of the soils to support the planned site activities.
1.3 Scope of Work
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;
• Define the general subsurface conditions of the site by observing excavations of up to 6
feet near the planned building footprints, review geological maps for the general area,
research slope stability,and review well logs from an existing well on the Project;
Envirotech Engineering Gcotechnical hlvestigation
Ph. 360-275'9374 page 1 Parcels 32235 31 00150. -00160&-00170
Fax: 360-275-4789 Mason Count*. Washington
Nmember 28. 2007
• Collect bulk samples at various depths and locations;
• Perform soils testing to determine selected index properties of the soils that include 6
visual classifications;
• Complete an engineering analysis supported by planned site alterations, and the surface
and subsurface conditions that were identified by the field investigation and soil testing;
and,
• Establish conclusions based on findings, and make recommendations for foundations,
slope stability, erosion control, earthwork construction requirements, and other
considerations.
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Fax: 360-275-4789 Mason County, Washington
November 28, 2007
2.0 SURFACE CONDITIONS
Information pertaining to the existing surface conditions for the Project was gathered on
November 6, and November 24, 2007 by Michael Staten, geotechnical engineer with Envirotech.
During the site visit, the type of geotechnical investigation was assessed, site features were
documented that may influence construction, soil samples were collected from selected locations,
and near-surface soils were visually classified. This Surface Conditions Section provides
information on general observations, vegetation, topography, drainage and slope/ erosion
conditions for the Project and surrounding areas that may impact the Project.
2.1 General Observations
The Project is currently vacant land with abandoned residential buildings on both Lot 150 and Lot
160. An old access or skidder road begins on Lot 160, and extends up the slope on Lot 170. East
State Route 106 cuts through the properties near the shore of Hood Canal. Residential rural
development exists beyond the property lines. Vegetation on and near the Project consists
primarily of cedars, firs, huckleberry, Oregon grape, and other trees and shrubbery common to
this area of the Pacific Northwest. A small creek with an apparent continuing flow, enters Lot
160, and exits at the highway drainage channel on Lot 170. 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 to steep sloping terrain. The building envelope
locations appear to be on relatively level terrain on Lot 150 and Lot 160. The building location
for Lot 170 is on approximately 20% sloping terrain. The topographic information provided in
this section was extrapolated from a public lidar source, and incorporated observations and field
measurements. See the Site Map in Appendix A and the Geological Map in Appendix B for an
illustration of the general topography with respect to the planned development.
2.2.1 Upslope Geomorphology
Ascending grades are located to the south of the planned development on each lot. This
slope ranges from approximately 65%on Lot 150, to about 34%on Lot 170. Other than
the creek, there are no apparent water bodies or wetlands located upslope from the
planned development.
2.2.2 Downslope Geomorphology
Descending grades on Lot 150 and Lot 160 are insignificant. Both proposed building
locations for these two lots are less than 5 feet above the elevation of the adjacent
Highway. Less than a 10 feet vertical relief exists on the north side of the Highway that
descends into Hood Canal. The descending grade on Lot 170 ranges from approximately
45%to 84%with a vertical relief of 37 feet beyond the planned building location.
2.3 Surface Drainage
Stormwater runoff originating upslope from the anticipated developments is expected to sheet
flow. Most surface water from Lot 160 and Lot 170 should migrate to the creek, and surface
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Fax: 360-275-4789 Mason Countti'. Washington
November 28. 2007
water from Lot 150 is anticipated to mostly flow directly to the highway drainage channel. Other
than the ordinary minimal erosion of the stream bank, excessive scour, erosion or other
indications of past drainage problems anywhere else on the properties were not observed.
2.4 Slope and Erosion Observations
The existing steep slopes 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 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.
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. In
addition,the adjacent paved roadway had no indications of longitudinal cracking, which is a good
indicator of earth movement.
HOO. ANASZ�,�F.Pd� l
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Aerial Photo from Mason County Website
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Fax: 360-275-4789 Mason Comity. Washington
November 28. 2007
3.0 SUBSURFACE INVESTIGATION
Information on subsurface conditions pertaining to the Project was gathered on November 6, and
November 24, 2007 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 C has pertinent information on
subsurface conditions for the Project, including two soil cross-sections, three test pit logs
representative of the bearing soils of the buildings, and one water well report.
3.1 Field Methods
Information on subsurface conditions for the Project was accomplished by observing soils within
existing excavations and newly excavated test pits near planned building footprints of
' in
approximately 3 feet to 6 feet below the existing ground surface. Information on subsurface
conditions also included reviewing water well reports originating from the Project and nearby
properties.
3.2 Field Sampling and Field Testing
One bulk sample was collected at the Project site at approximately 2 feet below the existing
ground surface that is representative of the bearing soils for the anticipated building locations.
The soil sample collected was secured and transported for possible laboratory testing.
Envirotech measured the relative density of the in-situ soils by gauging the resistance of hand
tools. Field testing results generally indicated medium dense soils in the upper 1 feet, and dense
to very dense soils below 1 feet within all anticipated building locations. Steep descending slopes
on Lot 170 and ascending slopes on Lot 150 exhibited loose soils in the upper 2 feet, medium
dense from 2 feet to 3 feet in depth, and dense below 3 feet in depth.
3.3 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 Shelton 1:100,000 Quadrangle, Washington," by Robert
L. Logan, 2003, the site soils are grouped as Continental Glacial Deposits from the Fraser
glaciation, Vashon Stade. Specific units for this Project include advance outwash, late
Wisconsinan (Pleistocene), Qge. From this geologic map, Qge is "glaciological sand and gravel
and latchstring clay, silt, and sand deposited during the advance of glaciers; sandy units
commonly thick, well sorted, and fine grained, with interlayered coarser sand,gravel, and cobbles
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and silt rip-up lag deposits at their base; may contain no glacial sediments; generally overlain by
till."
3.4 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 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 native soils beneath an organic/soil mixture of about 4 to 12 inches,
with no indications of borrowed fill. For engineering purposes, these native soils consist of
distinguishable layers,as presented below.
Soils within the upper 4 feet to 6 feet of natural ground are moist, brown poorly graded sand with
silt and gravel (SP-SM). Gravels are primarily coarse, and subrounded. Sand content was
primarily medium, and the fines content exhibited no plasticity.
Soils below the aforementioned poorly graded sand with silt and gravel layer to an unknown
depth is very dense, moist, light brown silty sand with gravel (SM), locally known as hardpan.
Gravel content was higher than the preceding soil layer, and was primarily subrounded and well-
graded. Sand content was primarily medium and coarse, and the fines content exhibited no
plasticity.
According to the well report originating on the subject property closest to the planned residence
on Lot 170, very dense soils extends to a depth of 56 feet below the ground surface overlying
brown clay. From experience, the identified clay stratum is most likely a silt with plasticity or a
silty clay.
3.4.1 Groundwater
From the water well report and knowledge of the general area, permanent groundwater is
expected to be greater than 75 feet below the ground surface for the building pad on Lot
170,and 40 feet below the building pads on Lot 150 and Lot 160. Perched groundwater at
r r content above the hardpan
shallow depths was not indicated on the well reports. Water p
P P
may be substantially increased during prolonged wet weather and/ or post-development
activities including on-site septic usage.
Overall, the shallow subsoil consists of a high permeable stratification due to the soil
classification and relative density. Permeability is an engineering property relating to
groundwater drainage, and is estimated to have a coefficient at or greater than 5 x 10-4
centimeters per second for this project.
3.5 Soils Testing
The soil samples obtained at the Project site during the field investigation were preserved and
transported for possible laboratory testing. Visual classification of soils was performed in the
Eiwirotecb Engineering Geolechnical Investigation
Ph. 360-275 9374 page G Parcels 32235 31 00150, -00160 &-00170
Fax: 360-275-4789 Mason County. Washington
November 28. 2007
r
field. The following soil tests were performed in accordance with the American Standards for
Testing and Materials (ASTM):
6 Visual Classifications (ASTM D2488)
3.5.1 Visual Classification
The general results from the visual classification are presented in the aforementioned
Subsurface Conditions Section at depths of up to 6 feet below the natural ground surface.
Specifically, soils above the hardpan consisted of approximately 20% to 45% gravel,
50%to 70%sand-sized soils, and 10%fines. 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.
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Photo 2: Poorly-graded sand with silt and gravel soils in test pit 1
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4.0 ENGINEERING ANALYSIS,CONCLUSIONS AND RECOMMENDATIONS
The following sections present engineering analysis and 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; and, soil
conditions that were identified from the geotechnical investigation that is summarized in the
Subsurface Investigation Section. Engineering analysis and recommendations for the Project that
is provided herein, includes pertinent information for building foundations, earthwork
construction, slope stability/erosion control, and seismic considerations.
4.1 Building Foundation Recommendations
Recommendations provided in this section account for the site development of three typical one-
or two-story, single family residential structure. Below the upper 12 inches of Project soils, there
are apparently two distinguishable layers of soil that will influence the bearing capacity and
settlement of the structures. 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, and deriving probable relative densities, unit weights
and angles of internal friction of the in-situ soils based on observed field conditions and soil
testing for this Project.
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. The soils on-site
have low frost susceptible characteristics and should be used only to the extents provided in this
report.
4.1.1 Bearing Capacity
For the existing site conditions, bearing values should increase with depth. Existing in-
situ soils at the Project site indicates that the structure can be established on shallow,
continuous or isolated footings. Foundations shall be established on relatively
undisturbed native soil. Alternatively, foundations may be constructed on selective re-
compacted native soil or compacted engineered fill as described in the Earthwork
Construction Recommendations Section of this report. Footing width and depth
recommendations shall be adhered to, and are based on 1500 pounds per square feet (psf)
maximum structural bearing pressure.
For a bearing capacity requirement of no more than 1500 psf, a minimum footing width
of 12 inches shall be placed at a minimum depth of 12 inches below the existing ground
surface for Lot 150 and Lot 160. A minimum footing width of 16 inches shall be placed
at a minimum depth of 12 inches below the existing ground surface for Lot 170. These
recommendations are made available based on adherence to the remaining
recommendations that are provided in this report.
4.1.2 Settlement
Total and differential settlement that a structure will undergo depends primarily on the
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November 28. 2007
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.
4.1.3 Concrete Slabs-on-Grade
Interior slabs, if utilized, should be supported on a minimum of 6 inches of compacted
granular material that is placed over undisturbed native subgrade or engineered fill.
Native soils found at the Project site is suitable material for supporting concrete slabs if
all deleterious material is removed. Although not required for the structural integrity of
the concrete slab-on-grade, a vapor barrier is usually used for damp-proofing. If vapor
barriers are used, it is suggested to utilize a barrier that is sufficiently thick to resist
puncturing during construction, or place a 2 inch layer of sand above the barrier prior to
placing the concrete slab.
4.2 Lateral Earth Pressures
Lateral earth pressures exerted through the backfill of a retaining wall are dependent upon several
factors including height of retained soil behind the wall, type of soil that is retained, degree of
backfill compaction, slope of backfill, surcharges, hydrostatic pressures, earthquake pressures,
and the direction and distance that the top of the wall moves. Significant retaining structures are
not anticipated for this Project. If retaining walls are later planned for this Project, prescriptive
requirements from the County should be adhered to. For retaining structures with a height
exceeding County prescriptive requirements, additional design parameters must be accounted for
in the retaining wall analysis, and recommendations should only be provided by a qualified
engineer after the type of backfill is acquired, inclination of backfill slope is estimated, and the
final wall height is determined.
4.3 Earthwork Construction Recommendations
Founding material for building foundations shall consist of undisturbed native soils. 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.
4.3.1 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, 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
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placement of additional native soil, engineered fill or structural concrete. It is suggested
that foundation excavations are inspected by a geotechnical engineer or qualified
professional in order to assess the bearing material prior to placement of structural
footings.
The top of the ridge on Lot 170 may be removed for this Project. See the Soil Profile in
Appendix C for an illustration. If removed, disturbed areas shall be lightly compacted,
and additional recommendations shall be adhered to as presented in the Erosion Control
Section of this report.
4.3.2 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 recommended 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 foot for each foot of compacted or re-compacted fill beneath the foundation. See the
illustration below.
FOOTING
COMPACTED
NATIVE SOILS
OR ENGINEERED I
FILL
I
II UNDISTURBED 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. Engineered
fill should consist of 60%to 100%gravel-sized material (particles between 3/16-inch and
3 inches),and less than 10%fines (particles passing#200 standard sieve)by weight.
Compaction shall be achieved in compacted lifts not to exceed 8 inches and 12 inches for
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.
4.3.3 Retaining Wall Backfill
As previously mentioned, significant retaining structures are not anticipated for this
Project. However, if used, native soils may be used as retaining wall backfill for this
Project. Backfill may also consist of engineered fill or borrow materials approved by a
geotechnical engineer. Placement, compaction and extents of retaining wall backfill
should also be specified by a geotechnical engineer or qualified professional.
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4.3.4 Wet Weather Considerations
Although the subsoil characteristics do not pose a great risk in regards to saturation,
additional provisions may be required during prolonged wet weather. Every precaution
should be made in order to prevent free moisture from saturating and ponding within
excavations. If the bottom of excavations used for footing placement changes from a
moist and dense characteristic as presented in this report to loose, saturated conditions,
then these soils become unsuitable for foundation bearing material. If this situation
occurs, a geotechnical engineer should be notified, or these soils should be completely
removed and replaced with suitable compacted material as presented above.
4.4 Slope Stabilityand Erosion Control
Landslides are natural geologic processes, and structures near slopes possess an inherent risk of
adverse settlement, sliding or structural damage due to these processes. These risks cannot be
eliminated for any site with sloping grades because gravity is constantly inducing strain on the
soil mass, and earthquakes exacerbates these strains. Geotechnical engineering provides 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 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. With
appropriate drainage and erosion control provisions for this Project during and after construction,
it is unlikely that this Project will experience excessive surficial movements. However,
maintenance of the slope must 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 and
property.
According to the Coastal Zone Atlas of Mason County, Washington, the Project is within and
near terrain labeled `Stable' and `Intermediate' regarding potential landslide activity. Stable
slopes are generally not prone to landslides due to small grades and accommodating geology.
Historically, intermediate terrains have no known landslides. However, this site is considered
inherently hazardous due the existing geology and/ or topography, and additional analyses and
recommendations concerning the slopes are presented herein. A Stability Map from the Coastal
Zone Atlas for the general area of this Project may be found on the following page of this report.
Although the Washington State Department of Natural Resources labeled the soils in this area as
highly erodible and highly unstable,the soil characteristics are extremely resistant to erosion and
stability concerns. It is Envirotech's opinion that no more than the presence of steep grades are
hazardous for this Project.
The Simplified Bishop Method, utilizing a spreadsheet program iterative approach, was used to
analyze the static stability of the site slopes. Various radii's and center points of the circle were
selected until the lowest factor of safety was found. Center points and radii's were carefully
chosen to exploit the weakest points of possible slip planes. In addition, conservative values were
used in the slope stability analysis in regards to topography, surcharges, water content, and
cohesion of the site soils.
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Seismic conditions were estimated utilizing worst case scenario values from the static analysis, a
horizontal acceleration coefficient of at least 0.15, and applying the applicable values to slope
stability charts. These stability charts were presented by the American Society of Civil Engineers
(ASCE)in the"Journal of Geotechnical and Geoenvironmental Engineering,"April 2002.
Anticipated building loads, building pad cuts, or impacts from septic drainfields are not expected
to have any detrimental influence on the global stability of the slopes, provided that the setback
requirements, drainage and all other recommendations in this report are adhered to. Based on the
aforementioned Project criteria, observations, slope stability analysis, and the recommendations
in this report, the Project has an acceptable factor of safety of over 1.5 relative to deep-seated,
static slope failures. Furthermore, an acceptable factor of safety of over 1.1 for seismic conditions
was also concluded for this Project. See the slope stability information in Appendix D for input
parameters and example of outputs.
For this project potential slip planes are confined to the face of the steep descending slope on Lot
170. Because of the soil classifications, slopes are usually considered stable for grades at or less
than the angle of repose. Currently, this slope grade is most likely near the angle of repose.
Minimum factor of safeties for static and dynamic conditions were estimated to be 1.8 and 1.2,
respectively.
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Map from Washington State Department of Ecology Website
4.4.1 Septic Drainfield Impacts
The approximate locations of the proposed septic drainfields are presented on the Site
Plan in Appendix A of this report. To account for the presence of drainfields for this
Project, the slope stability analysis accounted for saturation in the upper subsoil.
Saturation of the subsoil induces a greater soil unit weight, reduces cohesion, and reduces
the angle of internal friction. Based on the septic drainfield locations and slope stability
analysis for this Project, the drainfield is not expected to adversely influence the stability
of any slopes within and near the Project, or negatively impact the planned single family
residence.
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4.4.2 Building and Footing Setbacks
Conservative surcharges from the anticipated site development were used in the slope
stability analysis. 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 35 feet footing setback from the top of the nearby 80%
descending slopes on Lot 170.
STRUCTURE
T13P OF
SLIFE SLOPE
FACE-
- 35 FT MIN-- \- FOOTING
Lot 150 and Lot 160 do not have critical descending slopes with relation to the planned
buildings. There are no minimum setback requirements for the ascending slopes on each
property.
4.4.3 Temporary and Permanent Erosion Control
Based on the USCS description of the Project soils, the surface soils are considered to
have a low erodibility factor. Temporary erosion control measures may be required for
site development, and permanent erosion will be required. Extents of possible 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 measures may need to be employed if excessive erosion occurs or required by the
County or other prevailing agencies.
Erosion control during construction should include minimizing the removal of vegetation
to the least extent possible. If necessary, erosion control measures during construction
may include stockpiling cleared vegetation, temporary retention areas, silt fencing,
intercepting swales, berms, straw bales, plastic cover or other standard controls. Silt
fencing is presented in this report as the first choice for temporary erosion control. Any
erosion control should be located down-slope and beyond the limits of construction and
clearing of vegetation where surface water is expected to flow. If the loss of sediments
appears to be greater than expected, or erosion control measures are not functioning as
needed, additional measures must be implemented immediately. See Appendix F for
sketches and general notes regarding selected erosion control measures. The Site Map in
Appendix A depicts the recommended locations for erosion control facilities to be
installed, if necessary.
Permanent erosion control is necessary if substantial vegetation has not been established
within disturbed areas upon completion of the Project. Cut slopes for the roadway and
removal of the ridge top on Lot 170 should be permanently stabilized. Mulching,
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placement of sod, and/or seeding should be sufficient for this Project. Temporary erosion
control should remain in place until permanent erosion control has been established.
Selected recommendations for permanent erosion control are provided in Appendix F.
Additional erosion control measures that should be performed include routine
maintenance and replacement, when necessary, of permanent erosion control, vegetation,
drainage structures and/or features.
Sedimentation control should be adequate when utilizing the erosion control
recommendations as presented herein together with implementing appropriate erosion
controls with the degree of care as expected from a licensed contractor. Erosion control
information and specifications in addition to what is provided in this report may be found
in the current "Stormwater Management Manual for Western Washington," prepared by
the Washington State Department of Ecology Water Quality Program.
4.4.4 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 water mitigation will be required. This may include a
combination of swales, berms, drain pipes, infiltration facilities, or outlet protection in
order to divert water away from the structures.
From a geotechnical perspective, both perimeter footing drains and roof drains are
optional for all three single family residence. If footings are established at depths greater
than 2 feet below final grade, then perimeter footing drains are recommended. If utilized,
subsurface water intercepted in the perimeter footing drains, and stormwater collected
from roof drains shall be tight-lined to an appropriate infiltration area or outlet protection
area located downslope and at least 10 feet from any structure.
4.4.5 Vegetation Considerations
Vegetation is an excellent measure to minimize surficial slope movements and erosion on
slope faces and exposed surfaces. By removing trees, the root strength is decreased over
time, thereby lowering the `apparent' cohesion of the soil. Transpiration is decreased,
which results in additional groundwater, increased pore water pressure and less cohesion/
friction of the soil particles. Stormwater runoff also increases, and, fewer plants will
create less absorption of the force from raindrops, thereby creating the potential for
erosion hazards.
For this Project, the removal of vegetation is anticipated to be minimal. Only a few trees
within the building envelopes will be removed. Where removal outside the building
envelope is necessary, stumps and roots shall remain undisturbed as much as possible.
Vegetation shall not be removed within and beyond the setback limits delineated in the
Geologic Map in Appendix B of this report, except for removing of the ridge. However,
any tree deemed dangerous to life and/or property should be removed.
EnOrolech Enginccring Gcolechnical 111N,cstigation
Ph. 360-275 9374 page 14 Parcels 32235 31 00150. -00160&-00170
Fax: 360-275-4789 Mason County, Washington
NoN,ember 28. 2007
4.4.6 Off-site impacts
From a geotechnical position, it is Envirotech's opinion that the adjacent properties to the
proposed development should not be significantly impacted if all recommendations in
this report are followed. This is based on the slope stability analysis by accounting for
proposed surcharges and additional saturation of the soils. Drainage features that will be
utilized for this Project that have not been accounted for in this report shall include
proper mitigation as to not adversely impact properties beyond the Project.
4.5 Seismic Considerations
Soils immediately below the expected foundation depth for this Project are generally Type D,
corresponding to the International Building Code(IBC)soil profiles. If construction is established
on hardpan, Type C soils may be utilized. 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.
There are no known faults beneath this Project. The nearest Class `A' or Class `B' fault to this
property is the Hood Canal Fault Zone, in which the distal end is approximately 5 miles to the
west of this Project. This information is based on the USGS Quaternary Fault and Fold Database
for the United States.
The potential for liquefaction and other earthquake induced hazards are believed to be very low
for this Project. This is based on subsurface conditions such as soil characteristics and the lack of
a permanent shallow water table. Subgrade characteristics that particularly contribute to problems
caused by seismic events include submerged, 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. No significant sand stratifications are anticipated to
be within the upper 50 feet of the subsoil for this Project.
4.6 Driveway Considerations
Considerations for the planned single family residence ingress/ egress includes cutting into the
end of the steep slope located on Lot 170. Slope stability and erosion hazards will not be
compromised if the driveway is constructed in the location and within the general guidelines as
presented in this report. The Site Map in Appendix A, and the Typical Road Cross-Section in
Appendix G depict an illustration and the recommended driveway configuration for this Project.
The structural section of the proposed gravel surfaced driveway was designed based on the
USACE technical manual 5-822-12, titled "Design of Aggregate Surfaced Roads and Airfields."
The structural section shall consist of.
4 surface course, over
Prepared native subgrade.
The design method chosen, utilizes various inputs, including traffic and materials, to derive at
satisfactory and serviceability for a roadway structural section. Basic design inputs for calculating
the surface course thickness and other design parameters include ADT, Equivalent Single Axle
Eiwirotech Engineering Gcotechnical h estigation
Ph. 360-275-9374 page 15 Parcels 32235 31 00150. -00160 &-00170
FaN: 360-275-4789 Mason CountN,. Washington
November 28. 2007
Loads (ESAL), selected soil properties of the structural section, and properties of the subgrade
soils. Specifically,the design inputs used for this analysis is included in the following table:
Input Design
Descriptio Input Notes
n
Initial ADT 0/day Undeveloped property
ADT 10/day Trip generation estimate for 1 developed property
%Trucks 2% Assumed value
Design 25 yrs Design value for this analysis method
Life
%Growth 0.0% Assumed value
Surface 4"thick Minimum value based on USACE method.
6%fines
Table 1
Design Input
4.6.1 Surface Course
Based on the design inputs for the planned gravel surfaced roadway, the entire structural
section of the roadway is only 4 inches thick over competent soils. It is suggested to
increase the surface coarse to 6 inches for improved durability and erosion control. This
structural section should be composed entirely of surface coarse material consisting of
angular (crushed), well- or poorly-graded gravel (GW or GP) overlying prepared
subgrade or compacted engineered fill. In addition, the surface course material should
contain less than 5% fines (material passing the 4200 standard sieve), and have a
California Bearing Ratio(CBR)value of at least 17. Virtually all competent GW and GP
material have CBR's greater than 30. These design requirements are illustrated in the
following two tables:
US Standard Sieve Percent Finer
Size
3" 100
No. 4 0-20
No.200 0-5
Table 2
Gradation Requirements for Surface Course
Envirolech Engineering Geoteclukal Investigation
Ph. 360-275-9374 page 16 Parcels 32235 3 1 00150_ -001 G0&-00170
Fax: 360-275-4789 Mason County. Washington
November 28. 2007
1
Property Surface Course
CBR 17 min
Plastic Index 6 max.
Particle Angularity Angular
Table 3
Property Requirements for Surface Course
4.6.2 Roadway Earthwork Construction Recommendations
Engineered fill is not expected for driveway construction. However, if utilized for this
Project, it should meet the engineered fill materials and compaction requirements as
presented in Section 4.3 of this Report. Native subgrades beneath the engineered fill or
the surface course material of the planned roadway shall be prepared to a depth of 8
inches. Subgrade preparation shall include the removal of trees, brush and other organic
materials near the surface. The subgrade shall be compacted to a depth of 8 inches as
recommended for the native soils in Section 4.3 of this report.
Roadway embankments are not expected for this Project. Roadway cuts are expected near
the bottom of the slope at the end of the slope near the border of Lot 160 and Lot 170.
See the Site Map in Appendix A. Road cuts shall be flattened to at least a 2:1 slope. See
the Roadway Detail in Appendix G of this report.
Additional surface course material is optional for this Project. However, additional
material may reduce future maintenance responsibilities by hindering the migration of
fines to the surface of the roadway. Over time these fine soils accumulated within the
voids of the coarse material and reach the road surface where they are easily transported
by traffic,wind or stormwater. The removal of fines creates pot holes and a situation for
free standing water which may soften the subgrade. The accumulation of fine soils within
the surface course exacerbates the freeze/ thaw effect and increases the rate of
sedimentation. Periodic maintenance is required for all gravel surfaced roadways, and
should be maintained when necessary.
Einlrotech Engineering Geolechnical hwestigation
Ph. 360-275-9374 page 17 Parcels 32235 3100150. -00160&-00170
Fax: 360-275-4789 Mason Count)-. Washington
No\�embcr 28. 2007
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 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 protect life and property. Semantics such as `suggested' or `optional' refer
that the associated design or specification may or may not be performed. 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 ordinances or regulatory
codes, or broadening of accepted geotechnical standards may affect the 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,
Envirotec Engine ring
Michael Staten,P.E.
Geotechnical Engineer
Envirotech Engineering Geotechnical ]nvestigatioii
Ph. 360-275-9374 page 18 Parcels 32235 31 00150, -00160& -00170
Fav 360-275-4789 Mason County. Washington
November 28. 2007
APPENDIX A
SITE PLAN
SCALE, I INCH 60 FEET
0 30 0
CREEK PROPERTY LINE
LOT'150 LOT 160 LOT 170
PROPOSED DRAI IELD F
�
R❑POSED H❑ E C P> N
SILT FENCE IF.--- TP2 9
NECESSARY CTYP TP1
V<,
100
O
\(9
REQUIR&D—PERMANENT ROSION
CONTROL ON CUT SLOP S.-OF
�o DRIVEWAY
80
j PR❑ OSED DRIVEWAY
i
i N
i T 4 9
60\+a SFR
V � CNPNN
40 TP3 9 �- \ VRP1NPG� 06
PROPOSED
DRAINFIELDS
EXISTING STRUCTURE
TO BE REMOVED HOOD CANAL
EXISTING DRIVEW Y
20
PROJECT/ OWNER/ LOCATION,
THREE LOT
GE❑TECHNICAL REPORT
BUECHEL AND TEMPLEMAN
PARCEL 32235 31 00150, —160, 6 —170
NOTES LEGEND MASON COUNTY, WASHINGTON
1. TEMPORARY EROSION CONTROL MAY BE REQUIRED FOR THIS
SITE. PERMANENT EROSION CONTROL IS NECESSARY. GENERAL ENGINEER
LOCATIONS, AND ALTERNATIVES TO SILT FENCES MAY BE SILT FENCE ENVIROTECH ENGINEERING
UTILIZED AS EXPLAINED IN THE GEOTECHNICAL REPORT. �� SLOPE DIRECTION 74 NE HURD ROAD
2. CONTOURS ARE NOT PRECISE, AND ONLY DEPICT GENERAL BELFAIR, WASHINGTON 98520
TOPOGRAPHIC CONDITIONS. CONTOURS WERE EXTRAPOLATED =.ao EXISTING CONTOUR 360-275-9374
FROM A PUBLIC LIDAR SOURCE, AND INCORPORATED FIELD
MEASUREMENTS. I TP1 @ TEST P17 SITE PLAN
APPENDIX B
GEOLOGIC MAP
SCALE- I INCH 60 FEET
0
CREEK PROPERTY LINE
LOT '150 LOT,160 LOT 7171'__**0'
120
A
44
UPOSED"D RAD FIELD
Lr)
/\lIPOSED 'D'RAIl YP) cu
FROPOSED HD 4E (IYP)
SLIGHTLY
SLOPING
4�
10
VO
SF
B
SLOPE TOE T
4sl
so
RELATIVELY
FLAT
60 SFR
SF N
GE
A
40 9RR�J��
NZ16
PROPOSED SOILS, MEDIUM DENSE TO DENSE POORLY
DRAINFIELDS jp s GRADED SAND WITH SILT AND GRAVEL
(SP-SM) OVERLYING VERY DENSE TILL
HOOD CANAL
PROJECT/ OWNER/ LOCATION,
THREE LOT
20 GEOTECHNICAL REPORT
BUECHEL AND TEMPLEMAN
PARCEL 32235 31 00150, -160, & -170
NOTES LEGEND MASON COUNTY, WASHINGT13N
1. CONTOURS ARE NOT PRECISE, AND ONLY DEPICT GENERAL
TOPOGRAPHIC CONDITIONS. CONTOURS WERE EXTRAPOLATED ENGINEER]
FROM A PUBLIC LIDAR SOURCE, AND INCORPORATED FIELD BUFFER ENVIROTECH ENGINEERING
MEASUREMENTS. 74 NE HURD ROAD
SLOPE DIRECTION BELFAIR, WASHINGTON 98528
eo EXISTING CONTOUR 275-9374
GEOLOGIC MAP
APPENDIX C
SOIL INFORMATION
SCALE, 1 V CH -60 FEET
RIDGE MAY BE REMOVED Jo bo
MEDIUM DENSE T❑ DENSE PROPOSED HOUSE
P❑❑RLY GRADED SAND WITH
SILT AND GRAVEL (SP—SM)
CREEK EXISTING GRADE
HIGHWAY 106
VERY DENSE SM
AND GM HARDPAN
HO❑D CANAL
CEMENTED GRAV
ML—CL
SECTI❑N A—A
MEDIUM DENSE TO DENSE EXISTING GRADE
POORLY GRADED SAND WITH
SILT AND GRAVEL (SP—SM)
VERY DEN E SM
PR❑POSED H❑USE AND GM HARDPAN
HIGHWAY 106 C ME T D GRAVEL
H❑OD CANAL
ML—CL
SECTION B—B PROJECT/ OVNER/ LOCATION,
THREE L❑T
GE❑TECHNICAL REP❑RT
NOTES, BUECHEL AND TEMPLEMAN
PARCEL 32235 31 00150, —160, 6 —170
1) EXCEPT FOR POSSIBLE RIDGE REMOVAL ON LOT MASON COUNTY, WASHINGTON
170, MINIMAL GRADE CHANGES ARE EXPECTED
DUE TO BUILDINGS FOUNDED ON NEARLY FLAT TO
SLIGHTLY SLOPING SURFACES. LIGHT GRADING ENGINEER,
WILL BE REQUIRED TO ACHIEVE POSITIVE ENVIROTECH ENGINEERING
DRAINAGE FROM BUILDINGS. 74 NE HURD ROAD
2) SOIL PROFILE IS ACCURATE FOR THE OBSERVED BELFAIR, WASHINGTON 98528
SOILS AT THE TEST PIT LOCATIONS, AND PROBABLE 360-275-9374
SUBSURFACE CONDITIONS AT DEPTHS BELOW THE
OBSERVED SOILS. SOIL PROFILE
TEST NT LOG
TEST PF NUMBER TP-1
PROJECT: Three SFR Geotechnical Report DATE OF LOG: 11/06/2007
PROJECT NO: 0759 LOGGED BY: MICS
CLIENT: Buechel and Templernan EXCAVATOR: N/A
LOCATION: Lot 170 DRILL RIG: none
Mason County,Washington ELEVATION: NIA
INITIAL DEPTH OF WATER: N/A FINAL DEPTH OF WATER: N/A
sT�r ENEMAT rr TEST
solL sTRATA.
DEPTH SAMPLERS uses DESCRIPTION LL PI DEPTH N CURVE
AND TEST DATA 10
0
SP-SM Brown,moist,medium dense POORLY
GRADED SAND wfth SILT and GRAVEL
Grovel is coarse and subrounded to
1 subanguiar.Sand is primarily
well-graded.Non pim4lc.
Dense
2
S
• ;. .
SM
Very dense,ardpar.
ExcavaWn terminated at app oximatey
4.2 feet
5
8
8
9
10
No Gramdwater Encountered ENVIROTECH ENGINEERING
fits k*mmbw pwWm o*eo M bo►ft and WwW not be Engineering
k*rpreesd as bait kx10 w Of the&Ate aAe
TEST MT LOG
TEST PF NUMBER TP-2
PROJECT: Three SFR Geotechnical Report DATE OF LOG: 11/06/2007
PROJECT NO: 0759 LOGGED BY: MCS
CLIENT: Buechel and Templ®man EXCAVATOR: N/A
LOCATION: Lot 170 DRILL RIG: None
Mason County,Washington ELEVATION: NIA
INITIAL DEPTH OF WATER: NIA FINAL DEPTH OF WATER: N/A
sTAM)M PENETRATION TM
SOIL STRATA,
DEPTH SAMPLERS 113CS DESCRIPTION LL PI CURVE
AND TEST DATA N 10 30 50
G 0 - SP-SM Brown,motet,medium dense POORLY
GRADED SAND with SILT and GRAVEL
Gravel is curse and subrounded to
1 subangular.Sand is primarily
wel{-grgded.Non plastic.
Dense
2
3
4
5
SM Very dense'ha*W'
8 Excavation terrnirlated at apprOXI atiely
5.8 feet
7
8
9
10
No Groundwater Encountered ENVIROTECH ENGINEERING
nrs rftr,eNon pertain ordy co wa boft and aboard nor be Geotec finical Engineering
k*fpn*sd as N*v i or fhe ends alle.
TEST NT LOG
TEST RT NUMBER TP-3
PROJECT: Three SFR Geotachnicai Report DATE OF LOG: 11/0612007
PROJECT NO: 0759 LOGGED BY: MCS
CLIENT: Buechel and Templeman EXCAVATOR: N/A
LOCATION: Lot 150 DRILL RIG: None
Mason County,Washington ELEVATION: N/A
INITIAL DEPTH OF WATER: N/A FINAL DEPTH OF WATER: N/A
sTANnxm PENE"MTron TesT
SOIL STRATA,
DEPTH SAMPLERS USCS DESCRIPTION LL PI CURVE
DEPTH
AND TEST DATA N 10 30 50
0
SP-SM Brown,moist,medium derma POORLY
` GRADED SAND with SILT and GRAVEL.
. Gravel Is merse and subrourxied tD
1 subangular.Sand is primarily
i weN-graded.Non pim0c.
2 Very dense
Excavation terminated at app utffiately
3 2.5 feet
4
5
6
7
8
9
10
No Groundwater Encountered ENVIROTECH ENGINEERING
rnrs k mum pw4ohs only go M barip end ahmW nor be Geotachnical Engineedng
k#wp►ebd as be ft kxla&w or the w v ale.
TEST MT LOG
TEST FqT NUMBER TP-4
PROJECT: Three SFR Geotec finical Report DATE OF LOG: 11/0612007
PROJECT NO: 0759 LOGGED BY: MCS
CLIENT: Buechel and Templeman EXCAVATOR: N/A
LOCATION: Lot ISO DRILL RIG: None
Mason County, Washington ELEVATION: N/A
INOTIAL DEPTH OF WATER: N/A FINAL DEPTH OF WATER: N/A
STANMW PENEMA710N,
SOIL STRATA,
DEPTH SAMPLERS USCS DESCRIPTION LL PI DE7PTH N CURVE
AND TEST DATA 10 30 50
0
SP,SM Brown,moist,medium dense POORLY
GRADED SAND with SILT and GRAVEL.
_ Gravel Is coarse and subrounded to
1 subangular.Sand is primarily
well-graded-Non piestic.
2 Very dense
Excavation terminated at approximately
3
2.5 feet
4
5
8
7
8
9
10
No Groumxiwater Encountered ENVIROTECH ENGINEERM
n99 k*mN9on P&tWM 04y AD ara bw*V aW Mxx&nd be Geotechnical Engineering
rmerorwd se 6BYp i�cNtre d the entke aAe.
File Original and First Copy with Application No
lxperlmentofEcology WATER WELL REPORT
�a CopyyY DriOwner's
llera aCopry STATE OF WABIl�G"N Permx No ..
(1) OWNF.II<: Name.. .. Dick Buechel P.O.Box 1170, Union, Wa.
Adart>•s -
Mason _ .. ......�: ..__.�; see....35 . T.22.....N.. R. Y W.M.
0 (2) LOCATION OF WELL: County ......................._..__................_.
0 Bearing and distance from secUon or subdivision comer
10 WELL LOG:
(3) PROPOSED USE: Domestic ❑ Industrial ❑ MunWP+l� ) --
it anon ❑ Test Well ❑ Other ❑ Formation:Deacrtbt by color,character,site of material and structure,and
� Shots tMekneu of aptufera and the kind and nature of the material in each
stratum penetrated, t th at teart ono entry for each change of formation.
a_�wntr'c number of well KATMUAL FROM TO
N
N (4) TYPE OF WORK: lit r; than ones.... ....... ...................._...
ads ew well Method. Dug O ❑Deepened El --
Cable ❑ Drlveo ❑ - Sand & 8ve1 0
-
Reconditioned❑ Ratan Jetted ❑
O Hard_pan
LL ------- 2 5 --
r- (5) DIMENSIONS: Diameter of well U -• inches. Cemented gravel
----------- - r
O Drilled . _...S2._ ._.ft. Depth of completed well.. .._.......82__!t v 71
Brown clams___---- - — -71 78
R Cemented gravel
E (6) CONSTRUCTION DETAILS: Gravel & Water
h.402 Casing installed:.-...6...... Diem. from ........0_ $.to .......82. :<. — .---
Threaded❑ .' to.•.-..__ !t.
............ ft.
r Perforations: Yes❑ No Q — -
��VTT
Typeof Perforator used.-................ .._.... .....---••.................__......_..__. - -_ -�----
0 SIZB of perforations .................._.__ In. 1117 ............_..._.._._ In. - ----
_.__. perforattons tram ..........__........ !t,to _...... !t. - -- �s"a
_.it,to .___...._ -._.. R.
.................. perforations from _.........._. 7D 1
co perforations from .._...........__..tt.to ..._.---------_ —
r "-
ta Screens: Yes❑ No -
Mlinufaeturer'a N ...........
....._......-_..-.-._.......___.......--_-._._.. ---
G! Type_....__.._..._.. .-. _...._.- _ model No-........
_
Diam. Slot size ..._._--_.?'toad_._......... fl.to........ -.u. TI
Diem. .........._. S►ot size -. ......_from-..._........ !L to __.-_ it
CGravel packets: Yes❑ NoV Sire of gravel;............. --�-- -----•'- -
h" Gravel Placed from. -------......... .......ft.to_........._..... lit J _
18
Surface seal: Yes No O To what depth? .._»__.......__. !t
Material used in seal ....}3ellffJIIi te . .............................. .......
O Did any strata contain unusable water? Yea O No O -
Z 'Type of water? Depth of strata.......__.............. .
Method of sealing strata off... _..._................... '
(A
0 (7) PUMP: manulacturer's Nann ................. .............................._......._.._._._.
,0 -�--—
0 (8) WATER LEVELS Land-surface elevation
above mean sea level.... ._ . ..t16 _.... -
Static level ._._ 13. tt.below top of wen Dale .._.. ofl2.• __
0 Artesian Pressure _........ .............._lbs" per square Inch Date...._........................
Artesian water s co (C
ter Is by......................a p................_...................._...
W -
0 Drawdown is amount water level is --'-'- --��
+r
(9) WELL TESTS: 1OWCTV below static level ryary started.........��rJ..li._rte.._ . .. L'ompletetl •.-... .•••-".. iv.
Was a pump test made? Yes O No 10 If yes,by whom?.. _.... ._... ....... WELL DRILLER'S STATEMENT•
Yield: _ Bai./taln. with ft.drawdown after hrs.
E — This well was drilled under fray Jurisdiction and this report is
4.0 ---- -� •• true to the best of my knowledge and belief.
L
CL Recovery data (time taken as zero when pump turned off) (water level & Drills CO.
0 measured from well top to water level) B dell Pum ._............
NAME..........Pi......... .........P.. ..._.._..
0 Tune Water Level I Time Water Level I Tine WOter Level (Pmon, firm, or corporation) (Type or print)
d ._..-..... ......................_.._......1......................._...__... 1 E. Dickinson St. Shelton, Wa..........
.......................
= Address._...._._..3.................................
................. ............. .........._.....................................
.
Dace of seas [Sled].................... ......._ i ell rfller> ....
[[nn ._...ft. drowdown after-_..1 hrs.
Bailer test...._.... 45.gat./min. wlth....oU - .........
Arteltan flow g.p m. Date.__....................._...-_ __-_._ .. 13
.................. ........... - 00 2 ........ Date..... �.
Temperature of water............ Was a chemical analysts made? Yes O No
(USE ADDITIONAL SHLiTs 17 NECESSARY) �� a
FCV 0bP 1•20
APPENDIX D
SLOPE STABILITY
Simplified Bishop Method
Input
major slope minor slope
Vertical Relief(ft) 37 -10
Slope horizontal distance (ft) 44 100
Depth to top Unit weight friction angle, cohesion,
of soil layer(ft) of soil (pcf) phi, (deg) c(psf)
Soil 1 0 134 34 0
Soil 2 6 138 40 0
Soil 3 24 140 42 0
Soil 4 56 130 0 1200
Soil 5 71 0 0 0
Minor Slope 134 34 0
Surcharge (psf) 1500
Surcharge distance from top of slope 35 Surcharge must be beyond top of major slope
Factor of Safety, FS Trial 1 2.5 assumed value
Trial Radii (ft) 40
Output Center of circle at 40 ft to left of top of slope
Slope Inclination, beta (deg) 40.08 40 ft from center
90- beta (deg) 49.92
90 + beta (deg) 130.08
alpha (deg) 21.60 function of the radius offset
90- beta- alpha (deg) 28.31 function of the radius offset
(90)+beta+theta (28.33) function of the radius offset
Horizontal Length of all slices (ft) 129.42
Horizontal length from center(ft) 59.42 horizontal distance from center of circle to left end of 1st slice
Radius of slip plane 1 (ft) 37.22 for a slip circle at toe of slope
Factor of Safety, FS Trial 2 2.27
Factor of Safety, FS Trial 3 1.94
Factor of Safety, FS Trial 4 1.84
sin (beta) 0.64
sin (90-beta) 0.76
b h A alpha c phi
Slice Horizontal Left height Right height Ave. Slice Slice Slice Base W" cohesion friction cb+
Number Width ft of slice ft of slice ft Height ft Area (so Weight (lb) Inclination de ,sin al ha c angle de Wtan hi
1 12.9 0.0 15.3 7.7 99.3 13,389.4 58.1 1 11,360.4 0.0 40.0 11,226.9
2 12.9 15.3 24.4 19.9 257.4 35,217.1 41.6 23,363.2 0.0 40.0 29,529.4
3 12.9 24.4 29.9 27.2 351.7 48,301.8 28.6 23,108.1 0.0 42.0 43,458.6
4 12.9 29.9 32.6 31.2 404.3 55,674.0 17.1 16,338.2 0.0 42.0 50,091.7
5 12.9 32.6 40.6 36.6 473.5 65,358.6 6.2 7,094.1 0.0 42.0 58,805.2
6 12.9 40.6 49.3 44.9 581.5 80,475.3 4.3 6,016.5 0.0 42.0 72,406.1
7 12.9 49.3 55.2 52.3 676.3 93,753.6 15.1 24,345.51 0.0 42.0 84,353.0
8 12.9 55.2 54.3 54.8 709.2 98,358.3 26.4 43,414.8 0.0 42.0 87,853.9
490
12.9 54.3 40.6 47.5 614.1 85,043.7 39.0 51,681.3 0.0 42.0 73,854.8
12.91 40.6 0.0 20.3 262.4 35,902.3 54.6 25,009.3 0.0 40.0 25,741.4
231,731.4
Slice m(alpha) m(alpha) m(alpha) Weight from Wt. from W
Number(Trial FS1 Numerator1 (Trial FS2 Numerator2 (Trial FS3 Numerator2 Surcharge (lb) Minor Slope Total Wt R-b(10-#) h-b#
1 0.81 13,795.31 1.20 9,385.55 1.34 8,387.13 0 0 13,389 (46.48) 46.48
2 0.97 30,418.68 1.27 23,256.35 1.38 21,381.48 0 0 35,217 (33.54) 33.54
3 1.05 41,376.84 1.28 33,908.10 1.37 31,772.30 0 0 48,302 (20.60) 20.60
4 1.06 47,185.72 1.20 41,621.84 1.26 39,871.01 0 0 55,674 (7.65) 7.65
5 1.03 56,918.03 1.09 54,166.21 1.11 53,208.20 0 0 65,359 5.29 (5.29)
6 1.02 70,701.69 1.06 68,290.92 1.07 67,434.61 0 0 80,475 18.23 (18.23)
7 1.06 79,642.11 1.18 71,200.65 1.23 68,496.90 0 0 93,754 31.17 (31.17)
8 1.06 83,215.88 1.27 69,136.00 1.35 65,037.92 0 714 97,645 44.12 (44.12)
9 1.00 73,596.78 1.31 56,465.46 1.42 51,961.12 0 2,958 82,085 57.06 (57.06)
10 0.85 1.22 1.36 18,968.82 0 5,203 30,699 70.00 (70.00)
527,021.98 448,525.14 426,519.48
Trial Calc Radius (ft) F.S.
FS FS
2.50 2.27 30 3.78
2.27 1.94 40 1.81
1.94 1.84 50 2.19
,o (��° (e)Z to
(a)
r, ---D=2 g --D 2
_--
1'0 �
S `'A g �1 15 8 45
a
3D
n 4 4 4
f IS
z k =0.1 Z k6=02 2 kh.—0.3
6
o O 05 i 7.5 2 Z.5 Cie
0.5 1 15 2 25
a O5 1 1.5 2 25
rr (b)4 (d)4 M 4
3 3 3 @ t
to Ao
F _2 2 2
tee
F:. l: 3
F
� 7
n=O t:b s 0.2 k`
� 1< .0,�
p( N o° at a2 n3 a4 0-5ai az tt3 0A a5 °o at a2 o as a4 0.5
() r Y_fhi�r_wp-
Fig.4. Safety factor for slopes subjected to quasi-static horizontal force
sidered to be fully drained where dilation of the soil skeleton does make it possible to make an "educated guess"of the influence of
not cause any change in the magnitude of the pore water pressure. pore water pressure on the stability of slopes.
For the purpose of presenting the influence of the pore water
on the stability of slopes,the distribution of the pore water pres- Quasi-Static Seismic Effect
sure is described by coefficient r„ defined by Bishop and Mor- Seismic loads on slopes are often considered in design by includ-
genstern (1960) as
ing quasi-static forces due to seismic acceleration.While such an
u
(g) analysis ignores the seismic process (acceleration history) an
Y�l does not give any insight into the behavior of the structure, it is
where u=magnitude of the pore water pressure, y=soil unit routinely used in design.The kinematic approach of limit analysis
weight,and h=depth of the point on the failure surface below the was used here to strive at the data used to produce the charts in
slope surface. Stability charts for slopes with r„equal to 0,0.25, Fig.4.Coefficient kh represents the intensity of horizontal accel-
and 0.50 are presented in Fig. 3.The data in the charts in Fig. 3 eracion as a fraction of the gravity acceleration. The effect of
was created using a computer program written earlier (Micba- quasi-static forces was included in the analysis as an additional
lowski 1995). work term in the energy balance equation(Michalowski 1998).
Coefficient r„ is a rather cnrde manner of accounting for the No pore water pressure was considered in calculations with a
pore water pressure in a slope. If a well-defined flow net in a quasi-static seismic force. The quasi-static approach is a crude
slope is known,the corresponding pore pressure distribution can approximation of seismic effects, and charts involving another
be calculated and included explicitly in computations of the st<i- simplified concept(r„) to describe the pore water pressure distri-
bility number (or the safety factor). While such calculations are bution,in addition to kh, may not be indicative of the true safety
more accurate, presentation of the results in charts would be dif margin of slopes. Such charts would be an inappropriate tool for
ficult because of the large number of variables needed to describe analyzing the safety of slopes,particularly for liquefiable soils.
realistic flow nets. While the nature of calculations with pore Safety factor F, represented in the charts as F/tan cp, is an
pressures described in Eq. (8) is rather approximate, the results increasing function of N° (or e/yHtan y) up to some threshold
354/JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING/APRIL 2002
i
APPENDIX E
EROSION CONTROL
i
GEOTEXTILE FABRIC
WRAP AROUND TRENCH
TO AT LEAST ENTIRE
BOTTOM OF TRENCH
BEFORE PLACING GRAVEL 2'x2'x5' WOOD POST OR SILT FENCE
12' DEEP, 8' VIDE TRENCH EQUIVALENT OR BETTER L GEOTEXTILE FILTER FABRIC TYPE SHALL BE PER SPECIFIED IN
FILLED WITH 3/4' TO 1 1/2' THE 'STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOLND
WASHED GRAVEL BASIN,' OR APPLICABLE COUNTY STANDARDS
2.5 FT 2. GEOTEXTILE FILTER FABRIC SHALL BE PURCHASED IN A
DIRECTION OF WATER FLOW— CONTINUOUS ROLL CUT TO THE LENGTH ON EACH BARRIER TO
EXISTING AVOID USE [IF JOINTS. IF JOINTS ARE NECESSARY, FILTER FABRIC
12, GROUND SURFACE SHALL BE SPLICED TOGETHER ONLY AT A SUPPORT POST WITH A
2.3 FT MINIMUM 6-INCH OVERLAP AND SECURELY FASTENED AT BOTH ENDS
TO THE POST.
3. STANDARD FILTER FABRIC SHALL BE FASTENED USING 1'
e' STAPLES OR TIE WIRES (HOG RINGS) E 4 IN SPACING
4. POSTS SHALL BE SPACED AND PLACED AT DEPTHS INDICATED 1N
�I�T FENCE - CROSS SECTION THE DETAILS ON THIS SHEET, AND DRIVEN SECURELY INTO THE
N.T.S. GROUND.
5. WIRE MESH SHALL BE 2'X2'X14 GAl1Cf OR EOl1IV1LENT. THE
WIRE MESH MAY BE ELIMINATED IF EXTRA-STRENGTH FILTER
FABRIC (MONOFILAMENT), AND CLOSER POST SPACING IS USED.
GEOTEXTILE FABRIC
2'x2' WOOD POST (TYP) 6. A TRENCH SHALL BE EXCAVATED ACCORDING TO THE DETAILS ON
ON EQUIVALENT OR BETTER AND WIRE MESH THIS SHEET ALONG THE LINE OF THE POSTS AND UPSLOPE FROM
(? 6 FT MAX. O.C. THE SILT FENCE,
D.5 FT 7, SILT FENCES SHALL BE LOCATED DOVNSLOPE FROM THE
6 FT �1 CLEARING LIMITS ON THE PROJECT.
EXISTING
GROUND SURFACE
2 T
12' DEEP, B' WIDE I T
TRENCH FILLED WITH
3/4' TO 1 1/2' 2.5 FT
WASHED GRAVEL
BOTTOM EXTENTS ff SIMT FENCE - DETAIL PERMANENT EROSION CONTROL NOTES,
GEOTEXTILE FABRIC
N.T.S. SOD PLACEMENT
1. S® FOR GRASS STALES SHALL BE MACHINE CUT AT A 3/4-INCH UNIFORM THICKNESS AT
THE TIME OF CURING. MEASUREMENTS FOR THICKNESS SHALL EXCLUDE TOP GROWTH AND
GENERAL NOTES THATCH
1. SHOULD THE TEMPORARY EROSION AND SEDIMENT CONTROL MEASURES 2. STANDARD SIZE SECTIONS SOD FOR GRASS SVALES SHALL BE STRONG END" TO
SHOWN ON THESE PLANS PROVE TO BE INADEQUATE DURING CONSTRUCTION, SUPPORT THEIR OWN WEIGHT AND RETAIN THEIR SIZE AND SHAPE WHEN SUSPENDED BY THE
THE CONTRACTOR SHALL INSTALL ADDITIONAL EROSION AND SEDIMENT END OF A 3 FOOT SECTION.
CONTROL FACILITIES. 3, SOD FOR GRASS SVALES SHALL NOT BE HARVESTED E TRANSPLANTED WHEN
2.ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE EXCESSIVELY AS OR WET MOISTURE CONTENT MAY ADVERSELY AND
LT ITS SURVIVAL.
INSPECTED DAILY AND IMMEDIATELY MAINTAINED, IF NECESSARY. 4. SOD FOR GRASS STALES SHALL BE HARVESTED, DELIVERED AND PLACED WITHIN A
3.ALL EROSION AND SEDIMENT CONTROL FACILITIES AND DEVICES SHALL BE PERIOD OF 36 HOURS.
LEFT IN PLACE UNTIL THE UPSLOPE AREAS HAVE BEEN PERMANENTLY SEEDING FOR RAW SLOPES
STABILIZED,
1. BEFORE SEEDING, INSTALL NEEDED SURFACE RUNOFF CONTROL MEASURES SUCH AS
TEMPORARY EROSION CONTROL NOTES- GRADIENT TERRACES, INTERCEPTOR DIKES, SWALES, LEVEL SPREADERS AND SEDIMENT
BASINS.
FOR ALL AREAS WHICH HAVE BEEN STRIPPED OF VEGETATION OR EXPERIENCED 2. THE SEED BED SHALL BE FIRM WITH FAIRLY FINE SURFACE, FOLLOWING SURFACE
LAND DISTURBING ACTIVITIES, AND WHERE NO FURTHER WORK IS ANTICIPATED ROUGHENING. PERFORM ALL OPERATIONS ACCROSS OR PERPENDICULAR TO THE SLOPE.
FOR A PERIOD EXCEEDING THE LISTED CRITERIA BELOW, ALL DISTURBED AREAS 3. SEEDING RECOMMENDATIONS, AS SHOWN BELOW, AND SHOULD BE APPLIED AT THE RATE
MUST BE IMMEDIATELY STABILIZED WITH MULCHING, GRASS PLANTING OR OTHER OF 120 POUNDS PER ACRE
APPROVED EROSION CONTROL TREATMENT APPLICABLE TO THE TIME OF YEAR. 4. SEED BEDS PLANTED BETWEEN MAY 1 AND OCTOBER 31 WILL REQUIRE IRRIGATION AND
GRASS SEEDING ALOE WILL ONLY BE ACCEPTABLE DURING THE MONTHS OF OTHER MAINTENANCE AS NECESSARY TO FOSTER AND PROTECT THE ROOT STRUCTURE.
APRIL THROUGH SEPTEMBER. HOWEVER, SEEDING MAY PROCEED WHENEVER IT IS 5. SEED BEDS PLANTED BETWEEN NOVEMBER 1 AND APRIL 30, ARMORING OF THE SEED BED
IN THE INTEREST OF THE OWNER/CONTRACTOR, BUT MUST ALSO BE ALX?ENTED WILL BE NECESSARY, (e.g, GEOTEXTILES, JUTE MAT, CLEAR PLASTIC COVERING).
WITH MULCHING, NETTING OR OTHER APPROVED TREATMENT. 6. FERTILIZERS ARE TO BE USED ACCORDING TO SUPPLIERS' RECOMMENDATIONS. AMOUNTS
SHOULD BE MINIMIZED, ESPECIALLY ADJACENT TO VATER BODIES AND WETLANDS.
DRY SEASON (MAY 1 THRU SEPTEMBER 30) — THE CLEARING OF LAND,
INCLUDING THE REMOVAL OF EXISTING VEGETATION OR OTHER GROUND COVER, USE THE FOLLOWING RECOMMENDED SEED MIXTURE FOR EROSION CONTROL, 13R A COUNTY
MUST BE LIMITED TO ONLY AS MUNCH LAND AS CAN RECEIVE APPROPRIATE APPROVED ALTERNATE SEED MIXTURE.
PROTECTIVE COVER OR BE OTHERWISE STABILIZED, AFTER HAVING BEEN
CLEARED OR OTHERWISE DISTURBED , BY NO LATER THAN SEPTEMBER 30 OF A PROPORTIONS PURITY GERMINATION
GIVEN YEAR UNLESS IMMEDIATE STABILIZATION IS SPECIFIED IN THE EROSION NAME BY WEIGHT (7) (X) (X)
AND SEDIMENT CONTROL PLAN, ALL AREAS CLEARED ON OTHERWISE DISTURBED
MUST BE APPROPRIATELY STABILIZED THROUGH THE USE OF MULCHING, NETTING, REDTOP (ACROSTIS ALBA) 10 92 90
PLASTIC SHEETING, EROSION BLANKETS, FREE DRAINING MATERIAL, ETC., BY ANNUAL RYE (LOLIUM MULTIFLORIUM) 40 98 90
SEPTEMBER 30 OR SOONER PER THE APPROVED PLAN OF ACTION. UNLESS CHEWING FESUE 40 97 BO
OTHERWISE APPROVED BY THE COUNTY, SEEDING, FERTILIZING AND MULCHING (FESTUCA RUBRA COMMUTATA)
OF CLEARED OR OTHERWISE DISTURBED AREAS SHALL BE PERFORMED DURING (JAMESTOWN, BANNER, SHADOW, KOKET)
THE FOLLOWING PERIODS. MARCH I TO MAY 15, AND AUGUST 15 TO OCTOBER J. WHITE DUTCH CLOVER 10 96 90
SEEDING AFTER OCTOBER 1 WILL BE DINE WHEN PHYSICAL COMPLETION OF THE (TRIFOLIUM REPENS)
PROJECT IS IMMINENT AND THE ENVIROMENTAL CONDITIONS ARE CONDUCIVE TO
SATISFACTORY GROWTH, IN THE EVENT THAT PERANENT STABILIZATION IS NOT MULCHING
-- POSSIBLE, AN ALTERNATIVE METHOD OF GROUND COVER, SUCH AS MULCHING,
NETTING, PLASTIC SHEETING, EROSION BLANKETS, ETC., MUST BE INSTALLED BY 1, MATERIALS USED FOR MULCHING ARE RECOMMENDED TO BE WOOD FIBER CELLULOSE, AND
NO LATER THAN SEPTEMBER 30. SHOULD BE APPLIED AT A RATE OF 1000 POUNDS PER ACRE
2. MULCH SHOULD BE APPLIED IN ALL AREAS WITH EXPOSED SLOPES GREATER THAN 2-1
IN THE EVENT THAT CONSTRUCTION ACTIVITIES OR OTHER SITE DEVELOPMENT (HiORIZONTAL,VERTICAU.
ACTIVITIES ARE DISCONTINUED FOR AT LEAST 4 CONSECUTIVE DAYS, THE 3. MULCHING SHOULD BE USED IMMEDIATELY AFTER SEEDING OR IN AREAS WHICH CANNOT
OWNER/CONTRACTOR SHALL BE RESPONSIBLE FOR THE INSPECTION ON ALL BE SEEDED BECAUSE OF THE SEASON. ALL AREAS REQUIRING MULCH SHALL BE COVERED BY
EROSION AND SEDIMENT CONTROL FACILITIES IMMEDIATELY AFTER STORM NOVEMBER 1.
EVENTS, AND AT LEAST ONCE EVERY WEEK. THE OWNER/ CONTRACTOR SHALL
BE RESPONSIBLE FOR THE MAINTENANCE AND REPAIR OF ALL EROSION AN
SEDIMENT CONTROL FACILITIES.
WET SEASON (OCTOBER 1 THRU APRIL 30) — ON SITES WHERE UNINTERUPTED PROJECT/ OWNER/ LOCATION*
CONSTRUCTION ACTIVITY IS IN PROGRESS, THE CLEARING OF LAND, INCLUDING
THE REMOVAL OF EXISTING VEGETATION AND OTHER GROUND COVER, SHALL BE THREE LOT
LIMITED TO AS MUCH LAND AREA AS CAN BE COVERED OR STABILIZED WITHIN G E❑TECHNICAL REPORT
24 HOURS IN THE EVENT A MAJOR STORM IS PREDICTED AND/ OR EROSION AND
SEDIMENT TRANSPORT OFF-SITE IS OBSERVED. BUECHEL AND TEMPLEMAN
ALL CLEARED OR DISTURBED AREAS SHALL RECEIVE APPROPRIATE PROTECTIVE PARCEL 32235 31 00150, -160, & -170
COVER OR BE OTHERWISE STABILIZED, SUCH AS MULCHING, NETTING, PLASTIC MASON COUNTY, WASHINGTON
SHEETING, EROSION BLANKETS, FREE DRAINING MATERIAL, ETC., WITHIN 5 DAYS
AFTER HAVING BEEN CLEARED OR OTHERWISE DISTURBED IF NOT BEING ENGINEERi
ACTIVELY WORKED. SILT FENCING, SEDIMENT TRAPS, SEDIMENT PONDS, ETC., ENVIROTECH ENGINEERING
VILL NOT BE VIEWED AS ADEQUATE COVER IN AND OF THEMSELVES. IN THE
EVENT THAT ANY LAND AREA NOT BEING ACTIVELY WORKED REMAINS 74 NE HURD ROAD
UNPROTECTED OR HAS NOT BEEN APPROPRIATELY STABILIZED 5 DAYS AFTER BELFAIR, WASHINGTON 98528
HAVING BEEN CLEARED, ALL CONSTRUCTION ACTIVITY ON THE SITE, EXCEPT 360-275-9374
FOR APPROVED EROSION AND SEDIMENT CONTROL ACTIVITY, SHALL IMMEDIATELY
CEASE UNTIL SUCH A TIME AS AFOREMENTIONED LAND AREA HAS BEEN EROSION CONTROL
APPROPRIATELY PROTECTED OR STABILIZED.
i
APPENDIX F
DRAINAGE DETAILS
STEEL CLAMPS (TYP)
10 FT MIN SPACING 1/2 INCH DIAMETER
CORRUGATED TIGHTLINE SECURELY FASTENED TO PIPE
6-INCH MIN. DIAMETER
8-12 INCH QUARRY SPALL OR
APPROVED ENERGY DISSIPATOR
LEVEL SECTION
TVO 3-FOOT o 0.010 0 0 0 0
ANCHORS (TYP), 0000000000000° 1 FT MN.
N4 REBAR OR o 0 0 0 0 000
EQUIVALENT 3 FT MIN
GEOTEXTILE FABRIC
TIGHTLINE DETAILS
N.T.S.
FINAL GROUND
SURFACE GEOTEXTILE FABRIC WRAPPED
AROUND QUARRY SPALL
CORRUGATED TIGHTLINE 8-12 INCH QUARRY SPALL Q2
6-INCH MIN. DIAMETER APPROVED INFILTRATION MEDIA
0'..':•0�000000000
0 0°0000000000 1 FT NI T
0000000000000
SUBSURFACE iRFACE DRAINAGE DETAILS NOTE,
N.T.S. INFILTRATION FACILITY COMPONENTS
AND SIZE MAY NEED TO BE DETERMINED
BY A DRAINAGE ENGINEER AND/ OR
PREVAILING GOVERNMENT AGENCY.
PROJECT/ OWNER/ LOCATION
THREE LOT
6 IN MIN I NOTE GE❑TECHNICAL REPORT
SLOPES FOR GRASS-LINED SWALES SHALL NOT BUECHEL AND TEMPLEMAN
tFT MIN � EXCEED 5.07 WITHOUT APPROPRIATE ENERGY PARCEL 32235 31 00150, -160, & -170
DISSIPATORS. MASON COUNTY, WASHINGTON
ENGINEER,
GRASS-LINED SWALE ENVIROTECH ENGINEERING
N.T.S. 74 NE HURD ROAD
BELFAIR, WASHINGTON 98528
360-275-9374
DRAINAGE DETAILS
i
APPENDIX G
ROADWAY DETAILS
4' SURFACE COURSE
95X COMPACTION
2% MIN
ORIGINAL GRADE
2
1
PREPARED SUBGRADE
(SEE REPORT)
TYP M ROAD CROSS SBMON AWAY FROM SLOPE
PM TO SCALE
4' SURFACE COURSE
2-1 MAX 95% COMPACTION
ORIGINAL GRADE
EX. MIN
2
PREPARED SUBGRADE
(SEE REPORT)
TYPICAL ROAD CROSS SBCPION AT END OF RBXM
NCfr TO SCAIB
NOTES,
1. ROAD SHALL HAVE A MAXIMUM GRADE PER
PREVAILING GOVERNMENT STANDARDS.
2, ROAD SHALL BE A MAXIMUM OF 15 FEET WIDE PROJECT/ OWNER/ LOCATION,
OR IN ACCORDANCE WITH COUNTY REQUIREMENTS. THREE LOT
3, SURFACE COARSE MATERIAL SHOULD MEET OR GEOTECHNICAL REPORT
EXCEED THE GENERAL REQUIREMENTS AS PRESENTED
IN THE GEOTECHNICAL REPORT. BUECHEL AND TEMPLEMAN
4. THE PREPARED SUBGRADE SHALL EXTEND AT PARCEL 32235 31 00150, -160, 6 -170
LEAST 8 INCHES BELOW THE SURFACE COARSE AND MASON COUNTY, WASHINGTON
FOLLOW THE RECOMMENDATIONS AS PROVIDED IN THE
GEOTECHNICAL REPORT.
ENGINEER
ENVIROTECH ENGINEERING
74 NE HURD ROAD
BELFAIR, WASHINGTON 98526
360-275-9374
ROAD CR❑SS-SECTI❑N