HomeMy WebLinkAboutGEO2011-00019 BLD2011-00144 - BLD Engineering / Geo-tech Reports - 3/23/2011 MASON COUNTY
DEPARTMENT OF COMMUNITY DEVELOPMENT
Planning Division
P O Box 279, Shelton, WA 98584
(360)427-9670
Geotechnical ReportReview Acceptance Letter
March 23, 2011
STEPHEN JOHNSON INC
PO BOX 488
BELFAIR WA 98528
Case No.: GE02011-00019
Parcel No.: 122085111010
Proiect Description: GEO Report addendum has been submitted for the (bld2011-00144)
The Geotechnical Report for STEPHEN JOHNSON INC has been received and reviewed by the
Planning Department. The report was prepared by Michael Staten dated 2/21/2011.
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.
Sincqpely,
Allan Borden
Land Use Planner
Mason County Planning Department
Comments:
3/23/2011 Page 1 of 1 GE02011-00019
Mason County Review Checklist
For a Geotechnical Report
1
Instructions:
This checklist is intended to assist Staff in the review of a Geotechnical Report. The Geotechnical Report
is reviewed for completeness with respect to the Resource Ordinance. If an item is found to be not
applicable, the Report should explain the basis for the conclusion.The Report is also reviewed for clarity
and consistency. If the drawings, discussion, or recommendations are not understandable, they should be
clarified. If they do not appear internally consistent or consistent with the application or observations on
site, this needs to be corrected or explained. If resolution is not achieved with the author, staff should
refer the case to the Planning Manager or Director.
Applicant's Name: 6(nv�
Perm it# 74V V 0 00 `a_-` Parcel#
Date(s)of file�'oc�e t(s) reviewed: '�U ,� Feh`
(1) (a)A disc sion of general geologic conditions in the vicinity of the proposed development,
OK? . V Comment:
(b) A disc sion of specific soil types
OK?Comment: „
..(c) A disqu scion of ground.water conditions.
OK? V Comment:
(d) A disc scion of the upslope geomorphology
OK?L Comment:
(e) A dis ssion of the location of upland waterbodies.and wetlands
OK? I u Comment:
(f) A discussion of history of landslide activity in th activity in the vicinity, as available in the
refer ced maps and records
OK?__V Comment:
(2) A site pl which identifies.the im ort nt develop nt nd g logi fe res
OK?�Comment: t al
(3) Locations and logs of explora ory holes Qr probei.
OK? Comment:
(4) The area of the proposed d&velopmenV the boundaries of the hazard, and associated buffers and
setbacks s>611 be delineat d (top, both sidesO
to
n a geologic map of the site.
OK? Lol Comment: b"V A
(5) A minimum of one cross section at a dGale which adequately depicts the subsurface profile, and
which incor rates the detail_of proposed grade changes.
OK?Comment: (�
(6) A description and results o If ss ope stability analyses performed for both static and seismic loading
conditions.Analysis should examine worst case failures. The analysis should include the
Simplified Bishop's Method of Circles. The minimum static safety factor is 1.5, the minimum
seismic safe,�q factor is 1.1. and he quasi-st t' an $is coeffie is�L be a77 ��
OK. c/Comment: V
(7) (a)Appropr}ate restrictioni A placement of drainage features
OK? J Comment: Lei, AW%C C
(b) ApproViate restrictions on plac ent of septi dr in fields
OK? V Comment: M I
(c) Appropriate restriction o placement of compaqfed fills and foot' g
OK?_Comment:
(d) Recommended buffe s f m the la dslide hazar ar ass reline bluffs and the tops of other
slopes on the property.
Page 1 of 2 Form Effective June 2008
OK?_[LComment: L
(e) Recommended setbatksLfrom the landslide hazard areas shoreline bluffs and the tops of
other s opes on the property_
OK? Comment:
(8) Recommendations for the re aration of a detailed clearing and grading plan which specifically
identifies vegetation to be removed, a schedule for vegetation removal and replanting, and the
method of vegetation removal. N /t_
OK? Comment:
(g) Recommendations for the preparation of a detailed temporary erosion control plan which
identifies the specific mitigating measures to be implemented during construction to protect the
slope from erosion, landslides and harmful construction methods.
OK? Comment:
(10) An analysis f both on-site and off-site mpacts of the proposed development.
OK?Comment: G `
(11) Specifications of final develo t conditions such as, vegetativ management, drainage,
erosion control, and buffer widths. f
OK?_Comment:
(12) Recommendations for the re ration of structural mitigation or detai of other proposed
mitigation.
OK?��Comment:
(13) A site map drawn to scale showing the property boundaries, scale, north arrow, and the location
and nature of xisting and prop d evelompient on the site. A—
OK?_i Comment: G��✓ C,r
Are the Documents signed and stamped?
Type and #of License:
If not approved, what is the next action/recommendation for further action?
Reviewed by , on
Time spent in review:
SECOND REVIEW/UPDATE:
Reviewed by , on
Time spent in second review:
THIRD REVIEW/ UPDATE:
Reviewed by , on
Time spent in third review:
Disclaimer: Mason County does not certify the quality of the work done in this Geological Assessment
Page 2 of 2 Form Effective June 2008
Mason County Department of Community Development
Submittal Checklist For a Geotechnical Report
Instructions:
This checklist must be submitted with a Geotechnical Report and completed, signed, and stamped by the
licensed professional(s)who prepared'the Geotechnical Report for review by Mason County pursuant to
the mason County Resource Ordinance. If an item found to be not applicable, the report should explain
the basis ,or the conclusion-
Applicant/Owner �CJ��n ��t� ^y1 ,�LParcel# ��� S� ���� '
Site Address i✓t t7dl,rz6 Go(,r7 ,_ "Xrr
(1) (a)A discussion of general geologic conditions in the vicinity of the proposed development,
Located on page(s) 9
(b) A discussion of specific soile toes
Located on page(s) LZL�ts�c�vrvl p,
(c) A discussion of ground water conditi no s
Located on page(s)
(d) A discussion of the upslope geomorphology
Located on page(s) 3
(e) A discussion of the location of upland waterbodies and wetlands
Located on page(s) 3
(f) A discussion of history of landslide activity in the activity in the vicinity, as available in the
referenced maps and records
Located on pages}
(2) A site plan which identifies the irnporFant developo ent nd geologic features.
Located on Maps) grJiirvv✓\
(3) Locations and logs of exploratory holes or pro b s.
Located on Map(s) In a1-�
(4) The area of the proposed development, the boundaries of the hazard, and associated buffers and
setbacks shall be delineated (top, both sides, and toe)on a-geolo rc map of the site.
Located on Map(s) f� )j /d are ran c � 4-cuff. 4 o Gv�c inn
(5) A minimum of one-cross section at a scale which adequately depicts the subsurface profile, and
which incorporates the details-of proDosed grade changes.
Located on Map(s) ,6o t G
(6) A^--scription and rasul s of slope stability analyses performed for both static and seismic loading
conditions_Analysis shouid examine v;orst case failures.The analysis should include the
Simplified Bishop's l`viethod of Circles_The minimum static safety factor is 1.5, the minimum
seismic safety factor is 1.1. and the qua i-static analysis coe fiients should be a value of 0.15.
Located on page(s) /17', t:ZA,"kyn F,
(7) (a)Appropriate restrictions on placement of drainage features
Located on page(s) A Orr\ Ad ^ d o V\ 11
(b) Appropriate restrict* rs on placement of septic drain fields
Located on page(s) /�
(c) Appropriate restrictions on place nt of compacted fills and footings
Located on page(s) r,J - otuw1
Page 1 of 2 Form Effective June 2008
Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report.
(d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of other
slopes on the propert
Located on page(s) / ��c� Z
(e) Recommended setbacks from the land lide hazard areas shoreline bluffs and the tops of
other slopes on the property^
Located on page(s) /� V- Ad de41dv��-
(8) Recommendations for the preparation of a detailed clearing and grading plan which specifically
identifies vegetation to be removed, a schedule for vegetation removal and replanting, and the
method of vegetation removal.
Located on page(s) ;A
(9) Recommendations for the preparation of a detailed temporary erosion control plan which
identifies the specific mitigating measures to be implemented during construction to protect the
slope from erosion, land,sl' es and harmful construction methods.
Located on page(s) /t/
(10) An analysis of both on-site and VX1, e impacts of the proposed development.
Located on page(s) IS d U4 -, -2
(11) Specifications of final development conditions such as, vegetative management, drainage,
erosion control, and buffer widths. .
Located on page(s) /41, /S 'h
(12) Recommendations for the preparation of structural mitigation or details of other proposed
mitigation.
Located on page(s)
(13) A site reap drawn to stale showing the property boundaries, scale,north arrow, and the location
and nature of existing and proposed development on the site.
�/'Locatedon Map(s)_��� r�c,n (All
1, /'(c G{1 LO ( ��VCL S441 hereby certify under penalty of
perjury that 1 am a civil drigineer licensed in the State of Washington with specialized knowledge of
geoteGhnical/geological engineer ing or a(geologist or engineering geologist licensed in the State of
Washington with sp-cil€knowledge of the local conditions_t also certify that the Geotechnical
Report, dated ` e 5 �-f ZOO, and entitled ��"�ec 116ca I KO
s. O�n 'i meets all the requirements of the klason
County Resource Ordhance,Lands fide Hazard Section,is complete and true,that the assessment
demonstrates conclusively that the risks posed by the landslide hazard can be mitigated through the
included geotechnical design re^.ot-riniendations, and that ali hazards are mftate-d in such a manner as
to prevent harm to property and public heatth and safety.(Signature and Stamp)
It
J7
43045 v
�A �FGISTB(i�0
Page 2 of 2 Form Effective June 2008
Disclaimer: Mason County does not certify the quality of the work done in this Geotechnica€ Report.
�wv�rotech �wg�weert,wg
�eotechwacaL° EvLvCrovi mevADL °Dra�wage °R.0001WRI� For Aknjovy-)- �
' - -BAd �'`"' _ �,'
February 21, 2011
Stephen Johnson, Inc.
PO Box 488
Belfair,Washington 98528
RE: Geotechnical Report Addendum#1 for S. Johnson Single Family Residence, E. Cardinal
Court,Mason County,Washington
INTORDUCTION
Envirotech Engineering (Envirotech) has completed this geotechnical report addendum for the
above referenced project. The original report, dated February 1, 2010, was prepared by
Envirotech (Project #1005). This addendum was prepared in order to include the neighboring
parcel in the Belwood subdivision. The two neighboring parcels are Lot 55 and Lot 56 of the
Belwood Plat, parcel 12208 51 11010 and 12208 51 11014. Pertinent geotechnical design
parameters in this addendum apply to Lot 55 only. See the Site Plan attached to this addendum.
PROJECT INFORMATION
The development of this Project includes a typical 1-or 2-story single family residence. A gravel
driveway and septic features have already been constructed. The planned house is anticipated to
consist of continuous footings with stem walls or concrete slab-on-grade.
SOIL INFORMATION
The existing building pad is situated primarily within an earth cut, however fill of up to
approximately 18 inches is apparent on the downhill side of the pad.
Foundation soils were measured to be brown, moist, medium dense to dense Silty Sand with
Gravel (SM) over very dense hardpan. See the boring log attached to this addendum, and the
original geotechmcal report for complete geologic and soil information.
EARTHWORK AND FOUNDATIONS
Earthwork construction and foundations should follow the outline in the original report.
Specifically for Lot 55, any fill should not be utilized for foundations. Alternatively, fill may be
Envirotech Engineering Geotechnical Report Addendum#1
PO Box 984 Page 1 of 3 S. Johnson Single Family Residences
Belfair,Washington 98528 Lot 55,Belwood Plat
Ph. 360-275-9374 February 21, 2011
Fax.360-275-4789
re-compacted per the earthwork requirements.
SLOPE STABILITY AND EROSION CONTROL
Critical slopes have been have been addressed in the original geotechnical report, which
encompasses both parcels. Lot 55 has an additional descending slope to the north, and the
previously addressed southern slope has been slightly modified. The north slope has an average
grade of approximately 23%, and descends into a ravine. These slopes are not critical and are
deemed stable. The south slope is approximately 43%with a vertical relief of nearly 14 feet, and
is a result of a driveway cut to Lot 56.
Building Setback
All structures should be at least 15 feet from the top of the local descending slope exceeding 40%.
Vegetation
Vegetation recommendations provided in the original geotechnical report should be followed for
Lot 55.
Drainage
The general drainage recommendations provided in the original report should be followed for Lot
55. Specifically, drainage from roofs should be directed downslope to the southern end of the
property. From a geotechnical perspective, foundation drains are not warranted for Lot 55.
Erosion
Minor scour was observed along the site access. Generally, erosion problems are not evident.
Erosion control during construction should follow the guidelines depicted in the original
geotechnical report.
Envirotech Engineering Geotechnical Report Addendum#1
PO Box 984 Page 2 of 3 S. Johnson Single Family Residences
Belfair,Washington 98528 Lot 55,Belwood Plat
Ph. 360-275-9374 February 21,2011
Fax.360-275-4789
CONSLUSION
From a geotechnical position, it is our opinion that the subject property and adjacent properties
should not be significantly impacted if all recommendations in this addendum and the original-
report are followed.
Envirotech is pleased to submit this addendum. This addendum provided additional information,
conclusions and recommendations concerning the project. Please contact Michael Staten at 360-
275-9374 if you have any questions, comments, or require additional information.
Best Regards,
Envirotech Engineering
PTV CLYpF,V
�1G� of wnsy�ti T�
O?0 ,pF 43045� �ct�
,o Cis76R
�SS��NAL ENG`
Michael Staten, P.E.
Geotechnical Engineer
Envirotech Engineering Geotechnical Report Addendum#1
PO Box 984 Page 3 of 3 S.Johnson Single Family Residences
Belfair,Washington 98528 Lot 55,Belwood Plat
Ph 360-275-9374 February 21,2011
Fax.360-275-4789
ATTACHMENT
1. SITE PLAN
SCALE- 1 INCH = 40 FEET
0 5 10 20 40
EROSION
CONTROL EXIST NG SEPTIC
DRAINFIELD LOCATION
X 290 ,
LOT 55 X APP L❑CATI❑ OF
PARCEL 12208 51 11010 E STING HOUS
APP X, LOCATION OF
PROPOSED OUSE /280 No
x LOT 56
/ + PARCEL 12208 51 1 014
270
APPRX, 15FT BUILDING APPRX, TOP ❑F SL
SEA ck FROM TOP 260 EXCEEDING 40%
OF 40% SLOP
125FT±
250 PROPERTY LINE—/
EXISTING
DRIVEWAY VEGETATION BUFFER
(GRAVEL) EXISTING PER GE❑TECHNICAL
DRIVEWAY REPORT AND ADDENDUM
(PAVED)
PROJECT/ OWNER/ LOCATION-
SINGLE FAMILY RESIDENCE
NOTES, GE❑TECHNICAL REPORT
1. EROSION CONTROL MAY BE REQUIRED FOR THIS SITE. GENERAL LOCATIONS
ARE DEPICTED, AND ALTERNATIVES MAY BE UTILIZED AS EXPLAINED IN THE STEPHEN JOHNSON INC
GEOTECHNICAL REPORT. BELWOOD PLAT] LOT 55 AND LOT 56
2. CONTOURS WERE NOT PREPARED BY A LICENSED LAND SURVEYOR. LEGEND MASON COUNTY, WASHINGTON
CONTOURS WERE EXTRAPOLATED FROM A PUBLIC LIDAR SOURCE (PREVIOUS
GEOTECHNICAL INVESTIGATION), AND INCORPORATED FIELD MEASUREMENTS AS TEMPORARY ENGINEER-
EXPLAINED IN THE GEOTECHNICAL REPORT. 4-+ +EROSION CONTROL ENVIROTECH ENGINEERING
3. BOUNDARIES WERE NOT PREPARED BY A LICENSED SURVEYOR. LOCATION OF 74 NE HUR
PROPERTY LINES AND SITE FEATURES, SUCH AS TOP OF SLOPES, WATER � D ROAD
SLOPE INDICATOR BELFAIR, ROAD 96528
FEATURES, ETC.., WITH RELATION TO THE PROPERTY LINES MUST BE 360-275-9374
VERIFIED BY THE OWNER, RECOMMENDATIONS IN THIS REPORT PROVIDE --80� EXISTING CONTOUR
SETBACKS, DEPTHS, ETC.. WITH RELATION TO GEOLOGIC FEATURES, NOT ROPERTY LINES. TPle TEST PIT SITE PLAN ADDENDUM
P
ATTACHMENT
2. SOIL LOG
TEST PIT LOG
TEST PIT NUMBER TP-2
PROJECT: SFR Geotechnical Report DATE OF LOG: 2/18/2011
PROJECT NO: 1005 LOGGED BY: MCS
CLIENT: Stephen Johnson, Inc EXCAVATOR: NIA
LOCATION: Lot 55 of Belwood Plat DRILL RIG: None
Mason County, Washington ELEVATION: N/A
INITIAL DEPTH OF WATER: N/A FINAL DEPTH OF WATER: N/A
SOIL STRATA, STANDARD PENETRATION TEST
DEPTH SAMPLERS USCS DESCRIPTION LL PI CURVE
AND TEST DATA DEPTH N 10 30 50
0 . .................................................
..
SM Brown, moist, medium dense SILTY
SAND with GRAVEL. Gravel is primarily
- coarse and subangular to subrounded.
1 Sand is mostly well-graded. Low
plasticity.
2
3
Light brown and grey, very dense
4 Excavation terminated at approximately
4.0 feet
5
6
7
8
9
10
No Groundwater Encountered ENVIROTECH ENGINEERING
This information pertains only to this boring and should not be Geotechnical Engineering
interpreted as being indicitive of the entire site.
122085104023 122085104026 '� -AKI22085110013
122085110001 122085110004 122085110007 122085110010 122085110016 122085110020
122085105021 `e
N
122085105023
122085111001 122085111004 122085111007 122085111010
�» 12208511101Af
122085105048 122085105053
� 122084200020�
E CARDI AL CT 220
280
.4%
ti
122085112007
122085106023 122085106026 122085112001 122085112004 122085112013
ti O
�b
122080060010 c
122085001001 122085007001
122084300000:
122085007024
122085001053 122085007026 122083400010
N
1 inch = 100 feet
W 1:
1 inch = 0.02 miles
S