CANOD.pdfApplicant:
Critical Area File #:
Site Location: '
Project Description:
City of Edmonds
Critical Area Notice of 'Decision
Property Owner:
1l
Permit Number: p
Parcel Number:
❑ Conditional Waiver. No critical area report is required for the project described above.
1. There will be no alteration of a Critical Area or its required buffer.
2. The proposal is an allowed activity pursuant to ECDC 23.40.220, 23.50.020, and/or
23.80.040.
3. The proposal is exempt pursuant to ECDC 23.40.230.
EJ Erosion Hazard. Project is within erosion hazard area. Applicant must prepare an erosion and
sediment control plan in compliance with ECDC 18.30.
VCritical Area Report Required. ,1"he proposed project is within a critical area and/or'a critical area
buffer and a critical area report is required, A ct itical area report has been submitted and evaluated
for compliance with the following criteria pursuant to ECDC 23.40.160:
1. The proposal minimizes the impact on critical areas in accordance with ECDC 23.40.120,
Mitigation sequencing;
2. °nie proposal does not pose an unreasonable threat to the public health, safety, or welfare
on>oroff the development proposal site;
3. / The proposal is consistent with the general purposes of this title and the public interest;
4. Any alterations permitted to the critical area are mitigated in accordance with ECDC
23.40.110, Mitigation requirements.
5. i The proposal protects the critical area functions and values consistent with the best
available science and results in no net loss of critical functions and values; and
6. / The proposal is consistent with other applicable regulations and standards.
❑ Unfavorable Critical Area Decision. The proposed; project is not exempt or does not adequately
nnitigate its impacts on critical areas and/or does not comply with the criteria in ECDC 23.40.160 and
the provision of the City of Edmonds critical, area regulations. See attached findings of
noncompliance.
Favorable Critical Area Decision. The proposed project as described above and as shown on the
attached site plan meets or is exempt froin the criteria in E,CDC 23.40.160, review Criteria, and
complies with the applicable provisions of the City of Edmonds critical area regulations. Any
subsequent changes to the proposal shall void this decision pending re -review of the proposal.
❑ Conditions. Critical Area specific condition(s) have been applied to the permit number referenced
above. See referenced permit number for specific condition(s).
Notice on Title. Critical area notice on title recorded under AFN, _
Reviewer
Signature
7 z
Date
Appeals: Any decision to approve, condition, or deny a development proposal; or other activity based on the
requirements of critical area regulations may be appealed according to, and as part of, the, appeal procedore, if any,
for the permit or approval involved.
Revised 11/29/2016
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Mione SFR ��"n� '� � � t June 21, 2018
19015 Olympic View Drive Project #14012
Edmonds, Washington
Chris & Merin Mione
Olympic View Drive
Edmonds, Washington
Subject: Geologically Hazardous Areas — Development Standards J RIJ 2
Application #: BLD20171839 ' '�''�tl�"i
Project: Mione - Single Family Residence — Lot B
Project Address: 19015 Olympic View Drive
Mr. & Mrs. Mione:
The purpose of this letter is to specifically address the proposed development plan with respect
to the development standards for geologically hazardous areas, as set forth in Edmonds
Community Development Code (ECDC) 23.80.060 and 23.80.070. Due to the timing of the
original short plat subdivision application, the short plat subdivision application was evaluated
based on an older, vested version of the ECDC. At this time, the design for the building permit
for the new home to be constructed on Lot B must meet the requirements of the current
version of the ECDC. For the sake of brevity, this letter assumes a high degree of familiarity
with the proposed development and the subject property.
To be concise and to ensure completeness, the applicable ECDC code sections are included in
this letter for reference. The various code items will be listed below in bold and our response
will follow each listed item/requirement, or group of items, as appropriate.
23.80.060 Development standards — General requirements.
A. Alterations of geologically hazardous areas or associated buffers may only occur
for activities that:
1. Will not increase the threat of the geological hazard to adjacent properties
beyond predevelopment conditions;
2. Will not adversely impact other critical areas;
3. Are designed so that the hazard to the project is eliminated or mitigated to a
level equal to or less than predevelopment conditions; and
4. Are certified as safe as designed and under anticipated conditions by a qualified
engineer or geologist, licensed in the state of Washington.
Response to A. 1-
We have reviewed the referenced architectural, structural engineering, and civil engineering
plans for the proposed development and it is our opinion that the proposed development will
not increase the threat of the geological hazard to adjacent properties beyond predevelopment
conditions, will not adversely impact other critical areas, and is designed so that the hazard to
the project is eliminated or mitigated to a level equal to or less than predevelopment
conditions. It is our opinion that the proposed development is safe as designed and under
SOUTH FORK GEOSCIENCES, PLLC Page 1
PO Box 1 275
NORTH BEND, WA 98045
425-890-4858 1 AHQR W�(��)S r [.` 0 r u. ttrt.
Mione SFR June 21, 2018
19015 Olympic View Drive Project #14012
Edmonds, Washington
anticipated conditions. Andrew L. Glandon, LEG (Engineering Geologist/Owner, South Fork
Geosciences, PLLC) is a State of Washington licensed engineering geologist (License #2689).
B. Critical Facilities Prohibited. Critical facilities shall not be sited within geologically
hazardous areas unless there is no other practical alternative. [Ord. 4026 § 1 (Att.
A), 2016; Ord. 3527 § 2, 2004].
Response to B.:
This is not applicable since the proposed development is not classified as a critical facility.
23.80.070 Development standards — Specific hazards.
A. Erosion and Landslide Hazard Areas. Activities on sites containing erosion or
landslide hazards shall meet the requirements of ECDC 23.80.060, Development
standards — General requirements, and the specific following requirements:
1. Minimum Building Setback. The minimum setback shall be the distance
required to ensure the proposed structure will not be at risk from landslides for
the life of the structure, considered to be 120 years, and will not cause an
increased risk of landslides taking place on or off the site. A setback shall be
established from all edges of landslide hazard areas. The size of the setback
shall be determined by the director consistent with recommendations provided
in the geotechnical report to eliminate or minimize the risk of property
damage, death, or injury resulting from landslides caused in whole or part by
the development, based upon review of and concurrence with a critical areas
report prepared by a qualified professional;
2. Buffer Requirements. A buffer may be established with specific requirements
and limitations, including but not limited to, drainage, grading, irrigation, and
vegetation. Buffer requirements shall be determined by the director consistent
with recommendations provided in the geotechnical report to eliminate or
minimize the risk of property damage, death, or injury resulting from landslides
caused in whole or part by activities within the buffer area, based upon review
of and concurrence with a critical areas report prepared by a qualified
professional.
Response to A. I & 2:
The buffers and building setbacks from the landslide hazard areas were established in the
referenced Critical Areas Report for Geologically Hazardous Areas (SFG, January 11, 2017). The
current development plans are in accordance with the buffers set forth in the referenced
report. It is our opinion that the 10-foot buffers provide adequate mitigation for the landslide
hazard areas and no other setbacks are required. It is our opinion that the buffer will eliminate
or minimize the risk of property damage, death, or injury resulting from landslides caused in
whole or part by the development
3. Alterations. Alterations of an erosion or landslide hazard area, minimum
building setback and/or buffer may only occur for activities for which a hazards
analysis is submitted and certifies that:
a. The alteration will not increase surface water discharge or
sedimentation to adjacent properties beyond predevelopment
conditions;
SOUTH FORK GEOSCIENCES, PLLC Page 2
PO Box 1 275
NORTH BEND, WA 98045
425-890-4858 Iai.w.?iry. c_c .
Mione SFR
June 21, 2018
19015 Olympic View Drive Project #14012
Edmonds, Washington
b. The alteration will not decrease slope stability on adjacent properties;
and
c. Such alterations will not adversely impact other critical areas;
Res onse to 3a-�c:
The erosion/landslide hazard areas will not be altered in association with the proposed
development.
4. Design Standards within Erosion and Landslide Hazard Areas. Development
within an erosion or landslide hazard area and/or buffer shall be designed to
meet the following basic requirements unless it can be demonstrated that an
alternative design that deviates from one or more of these standards provides
greater long-term slope stability while meeting all other provisions of this title.
The requirement for long-term slope stability shall exclude designs that require
regular and periodic maintenance to maintain their level of function. The basic
development design standards are:
Response to 4:
The proposed development does not include features that require regular or periodic
maintenance with respect to long-term slope stability.
a. The proposed development shall not decrease the factor of safety for
landslide occurrences below the limits of 1.5 for static conditions and
1.2 for dynamic conditions. If stability at the proposed development site
is below these limits, the proposed development shall provide
practicable approaches to reduce risk to human safety and improve the
factor of safety for landsliding. In no case shall the existing factor of
safety be reduced for the subject property or adjacent properties;
Response to 4a:
The entire site is underlain by medium dense to dense Vashon advance outwash sediments.
These sediments were over -consolidated by the Vashon glacial ice sheet and there are not
adverse geologic conditions or ground water conditions on or near the site. As such, it is our
opinion that the likelihood of a deep-seated, rotational failure on or adjacent to the subject
property is low and a quantitative slope stability is not warranted for the geologic conditions
and the overall slope geometry of the subject property. The "landslide hazard areas" are only
areas that exceed the slope geometry criteria, and much of these areas were created by
previous grading. Slope stability analyses performed on similar slope geometry, geology, and
hydrology typically yield factors of safety well in excess of 2 for both static and seismic
conditions.
b. Structures and improvements shall be clustered to avoid geologically
hazardous areas and other critical areas;
Response to 4b:
It is our opinion that the proposed home and associated features are appropriately located with
respect to geologically hazardous areas.
SOUTH FORK GEOSCIENCES, PLLC isms= Page 3
PO Box 1 275
NORTH BEND, WA 98045
4258904858 1 ru)t'��,a� a,_c_.c (D��i'.
Mione SFR June 21, 2018
19015 Olympic View Drive Project #14012
Edmonds, Washington
c. Structures and improvements shall minimize alterations to the natural
contour of the slope, and foundations shall be tiered where possible to
conform to existing topography;
Response to 4c:
Though there is obviously grading and excavation associated with the proposed development, it
is our opinion that the proposed home and associated features are constructible, and the
required grading and excavation will not destabilize the subject or adjacent properties during
construction.
d. Structures and improvements shall be located to preserve the most
critical portion of the site and its natural landforms and vegetation;
Response to 4d.
As previously stated, it is our opinion that the proposed home and associated features are
appropriately located with respect to geologically hazardous areas.
e. The proposed development shall not result in greater risk or a need for
increased buffers on neighboring properties;
Response to 4e:
Based on our site specific subsurface exploration and knowledge of the geologic setting, it is our
opinion that the proposed development shall not result in greater risk or a need for increased
buffers on neighboring properties.
f. The use of retaining walls that allow the maintenance of existing natural
slope area is preferred over graded artificial slopes; and
Response to 1L.,
It is our opinion that the proposed grading and retaining walls fulfill the intent of this item to
the extent possible.
g. Development shall be designed to minimize impervious lot coverage;
Response to 4 :
It is our opinion that the proposed site plan fulfills the intent of this item to the extent possible
for the construction of a single-family residence and the associated driveway, in consideration
of the topography of the subject property.
5. Vegetation Retention. Unless otherwise provided or as part of an approved
alteration, removal of vegetation from an erosion or landslide hazard area or
related buffer shall be prohibited;
Response to 5:
As previously stated, the erosion/landslide hazard areas will not be altered is association with
the proposed development.
6. Seasonal Restriction. Clearing shall be allowed only from May 1st to October
1st of each year; provided, that the director may extend or shorten the dry
season on a case -by -case basis depending on actual weather conditions, except
that timber harvest, not including brush clearing or stump removal, may be
.........................
SOUTH FORK GEOSCIENCES, PLLC Page 4
PO Box 1 275
NORTH BEND, WA 98045 0425-890-4858 1 �r[bmr c°,_ct
Mione SFR June 21, 2018
19015 Olympic View Drive Project #14012
Edmonds, Washington
allowed pursuant to an approved forest practice permit issued by the city of
Edmonds or the Washington State Department of Natural Resources;
Response to 6:
Though a seasonal restriction may be required by the City of Edmonds as a condition of the
building permit, due to the free native soils present, it is our opinion that a seasonal restriction
for clearing and grading is not necessary, provided that the recommendations for temporary
erosion and sediment control set forth in our original geotechnical report for the short plat
subdivision (SFG, April 1, 2014) are followed.
7. Point Discharges. Point discharges from surface water facilities and roof drains
onto or upstream from an erosion or landslide hazard area shall be prohibited
except as follows:
a. Conveyed via continuous storm pipe downslope to a point where there
are no erosion hazard areas downstream from the discharge;
b. Discharged at flow durations matching predeveloped conditions, with
adequate energy dissipation, into existing channels that previously
conveyed storm water runoff in the predeveloped state; or
c. Dispersed discharge upslope of the steep slope onto a low -gradient,
undisturbed buffer demonstrated to be adequate to infiltrate all surface
and storm water runoff, and where it can be demonstrated that such
discharge will not increase the saturation of the slope; and
Response to 7a b & c:
Surface water and roof drains from the proposed development will be infiltrated. Due to the
outwash sands encountered in our subsurface explorations, it is our opinion that surface water
runoff and/or infiltration will not create additional risk with respect to the subject or adjacent
properties.
8. Prohibited Development. On -site sewage disposal systems, including drain
fields, shall be prohibited within erosion and landslide hazard areas and related
buffers.
Response to 8:
The proposed home will not utilize on -site sewage disposal.
B. Earth Subsidence and Landslide Hazard Area. In addition to the requirements of
this chapter, development proposals for lands located within the earth subsidence
and landslide hazard area as indicated on the critical areas inventory shall be
subject to the provisions of Chapter 19.10 ECDC.
Response to B..
The subject property is not in the Earth Subsidence and Landslide Hazard Area, as such this item
is not applicable.
C. Seismic Hazard Areas. Activities proposed to be located in seismic hazard areas
shall meet the standards of ECDC 23.80.060, Development standards — General
requirements. [Ord. 4026 § 1 (Att. A), 2016; Ord. 3527 § 2, 2004].
SOUTH FORK GEOSCIENCES, PLLC Page 5
PO Box 1 275
NORTH BEND, WA 98045
425-890-4858 1
Mione SFR June 21, 2018
19015 Olympic View Drive Project #14012
Edmonds, Washington
Response to C.:
Based on our previous study, the subject property is not in a seismic hazard area, as such this
item is not applicable. Our geotechnical report for the short plat (SFG, April 1, 2014) set forth
general seismic design considerations for the proposed development.
Closure
It is our opinion that the preceding code sections and responses adequately demonstrate that
the proposed development plan has addressed the development standards for geologically
hazardous areas (ECDC 23.80.060 and 23.80.070).
We have enjoyed working with you and we are confident that the information provided in this
letter will aid in the design and permitting of your project. If there are any questions about this
report, please feel free to contact us.
Sincerely,
Andrew L. Glandon, LEG
Engineering Geologist / Owner
South Fork Geosciences, PLLC
Referenced Documents:
Development Services Department: Planning — Building, February 8,2018, To: Jacob Strobl, jacob
@strobldesign.com, "RE: PLAN REVIEW COMMENTS #1 FOR PLAN CHECK # 20L7-L839 NEW SFR AT 1901s OLYMPIC
VIEW DRIVE (LOT B OF P1N20140075)", prepared by Mike Clugston, AICP, Associate Planner, City of Edmonds
City of Edmonds, Plan Review Comments — Engineering Division "RE: Application #: BLD20171839, Project: Mione -
Single Family Residence — Lot B, Project Address: 19015 Olympic View Drive, DATE: February 13, 2018, To: Jacob
Strobl, Strobl Design, jacob@strobldesign.com, From: Mitch Boyd, Stantec Consulting Services,
Mitch.Boyd@edmondswa.gov
SOUTH FORK GEOSCIENCES, PLLC Page 6
PO Box 1 275
NORTH BEND, WA 98045
425-890-4858 1
Mione SFR June 21, 2018
19015 Olympic View Drive Project #14012
Edmonds, Washington
"Stormwater Review Comments, City of Edmonds Engineering Division", To: Engineering Reviewer, Date: February
6, 2018, Project Name: Mione Lot B, Permit Number: BLD20171839, Address: 19015 Olympic View Drive, Review
Type: Building (SFR), Submittal Date: 12/28/2017, Reviewer: Zack Richardson, PE, City of Edmonds, Stormwater
Engineer
"Subject: Review Comment Response, Application #: BLD20171839, Project: Mione - Single Family Residence — Lot
B, Project Address: 19015 Olympic View Drive", South Fork Geosciences, PLLC, Project #14012, May 5, 2018
"Subject: Response to Planning Review #3 (PLN20140075), Mione Short Plat, Parcel # 00434600007800, 19011
Olympic View Drive, Edmonds, Washington", South Fork Geosciences, PLLC, Project #14012, January 11, 2017
"Critical Areas Report for Geologically Hazardous Areas, Mione Short Plat, Parcel # 00434600007800, 19011
Olympic View Drive, Edmonds, Washington", South Fork Geosciences, PLLC, Project # 14012, January 11, 2017
"Subject: Response to Planning Department 2nd Review Comments, Mione Short Plat, Parcel # 00434600007800,
19011 Olympic View Drive, Edmonds, Washington", South Fork Geosciences, PLLC, Project #14012, March 5, 2016
"Soil Assessment for Design Infiltration Rate, Mione Short Plat, Parcel # 00434600007800, 19011 Olympic View
Drive, Edmonds, Washington" South Fork Geosciences, Project #14012, April 19, 2015
"Subsurface Exploration, Geologic Hazards, and Preliminary Geotechnical Engineering Report, Mione Short Plat,
Parcel # 00434600007800, 19011 Olympic View Drive, Edmonds, Washington" South Fork Geosciences, Project
#14012, April 1, 2014
Referenced Plans:
"Mione Residence, 19015 Olympic View Dr., Edmonds, WA 98020", Strobl Design LLC
Sheets Al-A3 — Revised 5/17/2018
Sheet A4 — Revised 5/9/2018
Sheet A5-A6 — Revised 5/17/2018
Sheet S1.0, S1.1, S1.2, S1.3, S6.0, S8.0, S9.0 & S9.1— Dated 5/1/2018
"Site Retaining Walls, 17088 Mione Residence, 19011 Olympic View Dr, Edmonds, Washington 98020" CT
Engineering Inc.
Sheet SW1.0 — Dated 2/20/2018
"Mione Lot B SFR", Omega Engineering, Inc Project #14-0608
Sheets 1-6 — Dated 4/20/2018, Stamped 6/21/2018
"Drainage Report, Mione Lot B SFR", Omega Engineering, Inc., Stamped 6/21/2018
"Mione Short Plat for Chris Mione", Green Land Surveying, Job #2013.07, Drawing #SP-Mione
Sheets 1 & 2 — Printed 6/30/2017
..... ...
SOUTH FORK GEOSCIENCES, PLLC Page 7
PO Box 1 275
NORTH BEND, WA 98045 :
425-890-4858 1 r .� :.REVV@5F-(;E0,C,(`)u .
Mione SFR June 21, 2018
19015 Olympic View Drive Project #14012
Edmonds, Washington
Chris & Merin Mione
Olympic View Drive
Edmonds, Washington
Subject: Geotechnical Plan Review and Minimal Risk Statement
Application #: BLD20171839
Project: Mione - Single Family Residence — Lot B
Project Address: 19015 Olympic View Drive
Mr. & Mrs. Mione:
South Fork Geosciences, PLLC has been requested to provide a geotechnical engineering review
of the final building plans for the proposed development of constructing a new single-family
home on the subject property.
We have reviewed the referenced architectural, structural engineering, and civil engineering
plans and in our opinion the reviewed plans conform to the recommendations set forth in the
referenced geotechnical engineering report and subsequent soil infiltration assessment, critical
areas study, review comment responses and geologically hazardous areas documents that have
been prepared by South Fork Geosciences. Provided the recommendations presented in the
referenced reports and the development plans are properly followed with good construction
practices implemented, the areas disturbed by construction will remain stable, there will not be
an increase in the potential for soil movement, and the risk of damage to the subject property
and adjacent properties will be minimal.
We trust that this letter will aid in the completion of this project. We look forward to working
with you during construction to provide any special inspections required by the City of
Edmonds. If you have any questions regarding this letter, please feel free to contact us.
Sincerely,
Andrew L. Glandon, LEG
Engineering Geologist / Owner
South Fork Geosciences, PLLC
SOUTH FORK GEOSCIENCES, PLLC Page 1
PO Box 1 275
NORTH BEND, WA 98045
425-890-4858 1 N ay yv(P 1-j G ('_C) .
Mione SFR June 21, 2018
19015 Olympic View Drive Project #14012
Edmonds, Washington
Referenced Plans:
"Mione Residence, 19015 Olympic View Dr., Edmonds, WA 98020", Strobl Design LLC
Sheets Al-A3 - Revised 5/17/2018
Sheet A4 - Revised 5/9/2018
Sheet A5-A6 - Revised 5/17/2018
Sheet S1.0, S1.1, S1.2, S1.3, S6.0, S8.0, S9.0 & S9.1- Dated 5/1/2018
"Site Retaining Walls, 17088 Mione Residence, 19011 Olympic View Dr, Edmonds, Washington 98020" CT
Engineering Inc.
Sheet SW1.0 - Dated 2/20/2018
"Mione Lot B SFR", Omega Engineering, Inc Project #14-0608
Sheets 1-6 - Dated 4/20/2018, Stamped 6/21/2018
"Drainage Report, Mione Lot B SFR", Omega Engineering, Inc., Stamped 6/21/2018
"Mione Short Plat for Chris Mione", Green Land Surveying, Job #2013.07, Drawing #SP-Mione
Sheets 1 & 2 - Printed 6/30/2017
Referenced Documents:
Subject: Geologically Hazardous Areas - Development Standards, Application #: BLD20171839, Project: Mione -
Single Family Residence - Lot B, Project Address: 19015 Olympic View Drive", South Fork Geosciences, PLLC,
Project #14012, June 21, 2018
Development Services Department: Planning - Building, February 8,2018, To: Jacob Strobl, jacob
@strobldesign.com, "RE: PLAN REVIEW COMMENTS #1 FOR PLAN CHECK # 201-7-1-839 NEW SFR AT 1901s OLYMPIC
VIEW DRIVE (LOT B OF P1N20140075)", prepared by Mike Clugston, AICP, Associate Planner, City of Edmonds
City of Edmonds, Plan Review Comments - Engineering Division "RE: Application #: BLD20171839, Project: Mione -
Single Family Residence - Lot B, Project Address: 19015 Olympic View Drive, DATE: February 13, 2018, To: Jacob
Strobl, Strobl Design, jacob@strobldesign.com, From: Mitch Boyd, Stantec Consulting Services,
Mitch.Boyd@edmondswa.gov
"Stormwater Review Comments, City of Edmonds Engineering Division", To: Engineering Reviewer, Date: February
6, 2018, Project Name: Mione Lot B, Permit Number: BLD20171839, Address: 19015 Olympic View Drive, Review
Type: Building (SFR), Submittal Date: 12/28/2017, Reviewer: Zack Richardson, PE, City of Edmonds, Stormwater
Engineer
"Subject: Review Comment Response, Application #: BLD20171839, Project: Mione - Single Family Residence - Lot
B, Project Address: 19015 Olympic View Drive", South Fork Geosciences, PLLC, Project #14012, May 5, 2018
"Subject: Response to Planning Review #3 (PLN20140075), Mione Short Plat, Parcel # 00434600007800, 19011
Olympic View Drive, Edmonds, Washington", South Fork Geosciences, PLLC, Project #14012, January 11, 2017
"Critical Areas Report for Geologically Hazardous Areas, Mione Short Plat, Parcel # 00434600007800, 19011
Olympic View Drive, Edmonds, Washington", South Fork Geosciences, PLLC, Project # 14012, January 11, 2017
"Subject: Response to Planning Department 2nd Review Comments, Mione Short Plat, Parcel # 00434600007800,
19011 Olympic View Drive, Edmonds, Washington", South Fork Geosciences, PLLC, Project #14012, March 5, 2016
"Soil Assessment for Design Infiltration Rate, Mione Short Plat, Parcel # 00434600007800, 19011 Olympic View
Drive, Edmonds, Washington" South Fork Geosciences, Project #14012, April 19, 2015
"Subsurface Exploration, Geologic Hazards, and Preliminary Geotechnical Engineering Report, Mione Short Plat,
Parcel # 00434600007800, 19011 Olympic View Drive, Edmonds, Washington" South Fork Geosciences, Project
#14012, April 1, 2014
SOUTH FORK GEOSCIENCES, PLLC Page 2
PO Box 1 275
NORTH BEND, WA 98045
425 890 4858 1 r Nc a r r r r G QM
Mione Short Plat
January 11, 2017
19011 Olympic View Drive (Parcel # 00434600007800) Project #14012
Edmonds, Washington
Chris and Merin Mione
19011 Olympic View Drive
Edmonds, WA 98020
Subject: Response to Planning Review #3 (PLN20140075)
Mione Short Plat
Parcel # 00434600007800
19011 Olympic View Drive
Edmonds, Washington
Mr. Mrs. Mione:
The purpose of this letter is to provide a response to the referenced planning comments. This
letter will show the applicable excerpts from the referenced review document and the excerpt
will be followed by our response.
2. Geotechnical letter: The geotechnical letter dated March 5, 2016 indicates the erosion hazard can
be addressed through the submitted TESC plan pursuant to ECDC 23.80.050.G. However, the
letter does not adequately address the presence of the potential landslide hazard that was
identified on the site in 2014. On page 3, the report states that the slope does not meet the
criteria for a landslide hazard in ECDC Sections 23.80.020.13.1, 13.3, and 13.4 but does meet it for
the 40% standard in ECDC 23.80.020.13.2. However, the hazard is not then addressed as required
in ECDC 23.80.060 and 23.80.070.
Please have Mr. Glandon produce a report prepared in accordance with ECDC 23.80.050 and
23.40.090 which addressed Sections 23.80.060, 23.80.070 and 23.40.280 of Ordinance 3527.
Unless it is clear that the updated report addresses these requirements, independent review will
be required pursuant to ECDC 23.40.090.13 with the costs borne by the applicant. The geotech
report from South Fork Geosciences dated August 7, 2015 states that there are no critical areas
on the site, which is in contrast from the critical area determination for the parcel issued January
29, 2015 (CRA20140120). The determination states:
Your property is located on a hillside with a western facing slope. This slope varies between
areas near level, around the house, to areas on your property where the slope exceeds 40%
according to City LZOAR data. Due to the degree of the slope on and adjacent to the your
property, it was found that the site contains slopes that are steep enough to be considered
both an Erosion Hazard Area (over 15 1 slope) and a Landslide Hazard Area (over 40%
slope). Your property also includes the Alderwood and Alderwood-Everett USDA soil series
types. Both of these soil series types are listed in section 23.80.020 ECDC which identifies soil
series that have characteristics leading to possible severe to very severe erosion occurrences.
Please submit an updated report which addresses the presence of these possible hazards on the
site relative to the proposed development. Reference can be made to the'Limited Report
Requirements for Stable Erosion Hazard Areas' in ECDC 23.80.050.G if that is applicable in this
instance; otherwise, submit a report prepared in accordance with ECDC 23.80.050 and 23.40.090
which addressed 23.80.060, 23.80.070 and 23.40.280.
.....� l
SOUTH FORK GEOSCIEIVCES PLLC
PO Box 1 275
NORTH BEND, WA 98045
425-831-2023 1 &E QREwQR" �aE-C.Q—M,
Mione Short Plat January 11, 2017
19011 Olympic View Drive (Parcel # 00434600007800) Project #14012
Edmonds, Washington
Response:
Please see the attached Critical Areas Report for Geologically Hazardous Areas, per ECDC
23.80.050. This report will serve to update the geologic hazards section of our referenced soils
report for the subject property and proposed development (SFG, April 2014). The information
in the referenced report with respect to all other soil design information is still applicable to the
proposed development.
Closure
We have enjoyed working with you on this project and are confident that the information
provided in this letter will aid in the design of your project. If there are any questions about this
report, please feel free to contact us.
Sincerely,
Andrew L. Glandon, LEG, CPESC
Engineering Geologist / Owner
South Fork Geosciences, PLLC
Attachment: Mione Short Plat Critical Areas Report
References:
"RE: Planning review #3 of civil improvement plans for short plat (PLN20140075)" Mike From: Clugston, Associate
Planner, City of Edmonds, October 6, 2016
"Subject: Response to Planning Department 2nd Review Comments, Mione Short Plat, Parcel # 00434600007800,
19011 Olympic View Drive, Edmonds, Washington", South Fork Geosciences, PLLC, Project #14012, March 5, 2016
"Soil Assessment for Design Infiltration Rate, Mione Short Plat, Parcel # 00434600007800, 19011 Olympic View
Drive, Edmonds, Washington" South Fork Geosciences, Project #14012, April 19, 2015
"Subsurface Exploration, Geologic Hazards, and Preliminary Geotechnical Engineering Report, Mione Short Plat,
Parcel # 00434600007800, 19011 Olympic View Drive, Edmonds, Washington" South Fork Geosciences, Project
#14012, April 1, 2014
SOUTH FORK GEOSCIENCES, PLLC Page 2
PO Box 1 275
NORTH BEND, WA 98045
425-831-2023 1t 1r,Ri vyM r, e.oOr
Mione Short Plat January 11, 2017
19011 Olympic View Drive (Parcel # 00434600007800) Project #14012
Edmonds, Washington
Critical Areas Report for Geologically Hazardous Areas
Mione Short Plat
Parcel # 00434600007800
19011 Olympic View Drive
Edmonds, Washington
The purpose of this report to fulfill the requirements of the Edmonds Community Development
Code (ECDC) as set forth in previous planning department reviews. To ensure completeness,
this report will include excerpts of the ECDC, specifically ECDC 23.80.50, and our responses will
follow each code item or series of items, as appropriate.
From ECDC 23.80.50
Critical area report requirements for geologically hazardous areas are generally met through
submission to the Director of one of more geotechnical engineering reports. In addition to the
general critical area report requirements of section 23.40.90, critical area reports for geologically
hazardous areas must meet the requirements of this Section and ECDC Chapters 19.05 and 18.30 as
applicable. Critical area reports for two or more typos of critical areas must meet the report
requirements for each relevant type of critical area. Geotechnical report(s) submitted for the purpose
of critical areas reviews are required as necessary in addition to reports, data and other information
mandated per ECDC Titles 18 and 19.
A. Preparation by a Qualified Professional. (details omitted for the sake of brevity)
Response.
Andrew L. Glandon, LEG, CPESC is a licensed engineering geologist in the State of Washington
(License #2689) with 18 years of professional experience as an engineering geologist in the
Puget Sound region. Mr. Glandon is also a Certified Professional in Erosion and Sediment
Control (CPESC #3370), as administered by EnviroCert International, Inc.'. Mr. Glandon's
credentials fulfill the requirements for a Qualified Professional.
B. Area Addressed in Critical Area Report. The following areas shall be addressed in a critical
area report for geologically hazardous areas:
1. The project area of the proposed activity; and
2. All geologically hazardous areas within 200 feet of the project area or that have
potential to be affected by the proposal
Rf tpons ^
There was no observed evidence of current or past landslide activity on or within 200 feet of
the subject property. The approximate location of the landslide hazard area on the subject
property is shown in the attached figure titled "Landslide Hazard Areas and Buffers". These are
the areas defined by ECDC 23.80.20 B (2), which are any areas with a slope of 40 percent or
greater that is in excess of 10 feet in vertical height.. None of the other landslide hazard area
criteria was observed. Based on our knowledge of the area and our review of the geologic and
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Mione Short Plat January 11, 2017
19011 Olympic View Drive (Parcel # 00434600007800) Project #14012
Edmonds, Washington
other mapping resources referenced in our geotechnical report (SFG, April 2014), it is our
opinion that there are not any off -site critical areas that are likely to impact the proposed
development.
C. Geological Hazards Assessment. A critical area report for a geologically hazardous area shall
contain an assessment of geological hazards including the following site- and proposal -
related information at a minimum.
1. Site and Construction Plans. The report shall include a copy of the site plans for the
proposal showing:
a. The type and extent of geologic hazard areas, any other critical areas, and
buffers on, adjacent to, within 200 feet of, or that are likely to impact the
proposal;
b. Proposed development, including the location of existing and proposed
structures, fill, storage of materials, and drainage facilities, with dimensions
indicating distances to the floodplain, if available;
c. The topography, in two -foot contours, of the project area and all hazard areas
addressed in the report; and
d. Clearing limits;
Response:
As previously stated, based on our knowledge of the area and our review of the geologic and
other mapping resources referenced in our geotechnical report (SFG, April 2014), it is our
opinion that there are not any off -site critical areas that are likely to impact the proposed
development. The referenced engineering plans for the project show the information set forth
inC.1.b,c&d.
Assessment of Geological Characteristics. The report shall include an assessment of
the geologic characteristics of the soils, sediments, and/or rock of the project area
and potentially affected adjacent properties, and a review of the site history regarding
landslides, erosion, and prior grading. Soils analysis shall be accomplished in
accordance with accepted classification systems in use in the region. The assessment
shall include, but not be limited to:
a. A description of the surface and subsurface geology, hydrology, soils, and
vegetation found in the project area and in all hazard areas addressed in the
report;
b. A detailed overview of the field investigations, published data, and references;
data and conclusions from past assessments of the site, and site specific
measurements, test, investigations, or studies that support the identification of
geologically hazardous areas; and
c. A description of the vulnerability of the site to seismic and other geologic events;
Response,
All of these items were set forth in the referenced geotechnical report for the project (SFG,
April 2014).
3. Analysis of Proposal. The report shall contain a hazards analysis including a detailed
description of the project, its relationship to the geologic hazard(s), and its potential
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Mione Short Plat
January 11, 2017
19011 Olympic View Drive (Parcel # 00434600007800) Project #14012
Edmonds, Washington
impact upon the hazard area, the subject property, and affected adjacent properties;
and
4. Minimum Buffer and Building Setback The report shall make a recommendation for the
minimum no -disturbance buffer and minimum building setback from any geologic
hazard based upon the geotechnical analysis.
Response:
Between this report and our referenced geotechnical report, it is our opinion that Item #3
above has been fulfilled. The landslide hazard areas and the 10-foot buffers are shown in the
attached figure titled "Landslide Hazard Areas and Buffers". It is our opinion that the 10-foot
buffers provide adequate mitigation for the landslide hazard areas and no other setbacks are
required.
D. Incorporation of Previous Study. Where a valid critical areas report has been prepared within
the last five years for a specific site, and where the proposed land use activity and
surrounding site conditions are unchanged, said report may be incorporated into the required
critical area report. The applicant shall submit a hazards assessment detailing any changed
environmental conditions associated with the site.
Restae nse:
To our knowledge, there are not any previous studies to incorporate into this study.
Mitigation of Long -Term Impacts. When hazard mitigation is required, the mitigation plan
shall specifically address how the activity maintains or reduces the pre-existing level of risk to
the site and adjacent properties on a long-term basis (equal to or exceeding the projected
lifespan of the activity or occupation). Proposed mitigation techniques shall be considered to
provide long-term hazard reduction only if they do not require regular maintenance or other
actions to maintain their function. Mitigation may also be required to avoid any increase in
risk above the pre-existing conditions following abandonment of the activity.
Response:
The hazard mitigation that is required by the ECDC is buffering and setback of the landslide
hazard area, which does not require any maintenance to maintain function. As such, it is our
opinion that additional mitigation for long-term impacts is not warranted.
Additional Technical Information Requirements for Erosion and Landslide Hazard Areas. In
addition to the basic critical area report requirements for geologically hazardous areas
provided in subsections A through E above, technical information for erosion and landslide
hazard areas shall meet the requirements of ECDC 19.05 and include the following
information at a minimum.
1. Site Plan. The critical area report shall include a copy of the site plan for the proposal
showing:
a. The height of slope, slope gradient, and cross section of the project area;
b. The location of sprirgs, seeps, or other surface expressions of ground water on
or within two hundred feet of the project area or that have potential to be
affected by the proposal;
c. The location and description of surface water runoff features;
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PO BOX 1 275
NORTH BEND, WA 98045
425-831-2023 1 &!gDRE V E� O OM:
Mione Short Plat January 11, 2017
19011 Olympic View Drive (Parcel # 00434600007800) Project #14012
Edmonds, Washington
Response:
a. The referenced civil engineering plans for the project show the slopes and 2-foot contours of
the project site. The slope areas of focus range from approximately 2.25H:1V to 1.4H:1V
(Horizontal:Vertical), or 44 to 71 percent. Since we do not anticipate excessively deep
foundation excavations in association with development of the western lot, it is our opinion
that a cross section of the slope is not warranted.
b. & c. No springs, seeps, other surface expressions of groundwater, or surface water runoff
features were noted in our prior site reconnaissance. As such, these features are not shown on
the civil engineering plans for the project.
2. Hazards Analysis. The hazards analysis component of the critical areas report shall
specifically include;
a. A description of the extent and type of vegetative cover;
b. A description of the subsurface conditions based on data from site specific
explorations;
c. Descriptions of surface and ground water conditions, public and private sewage
disposal systems, fills and excavations, and all structural improvements;
Response:
It is our opinion that for the sake of a short plat subdivision, all of these items were adequately
assessed and described in the referenced geotechnical report for the project (SFG, April 2014).
d. An estimate of slope stability and the effect that construction and placement of
structures will have on the slope over the estimated life of the structure;
Response, -
The entire site is underlain by medium dense to dense Vashon advance outwash sediments.
These sediments were over -consolidated by the Vashon glacial ice sheet and there are not
adverse geologic conditions or ground water conditions on or near the site. As such, it is our
opinion that the likelihood of a deep-seated, rotational failure on or adjacent to the subject
property is low. The "landslide hazard areas" are only areas that exceed the slope geometry
criteria, and much of these areas were created by previous grading. It is our opinion that the
observed stability over the life of the existing structure, approximately 67 years, is adequate
evidence of the slope stability for the future, since the proposed construction will not be within
or impact the "landslide hazard areas". It is our opinion that the new structures and features
will not negatively impact the slope stability and the 10-foot buffer provides adequate
mitigation.
e. An estimate of the bluff retreat rate that recognizes and reflects potential
catastrophic events such as seismic activity or a one -hundred year storm event;
Response:
A bluff retreat rate estimation is not applicable to the subject property or a slope of this nature,
since the geometry is not extreme and there is not an ongoing process that creates accelerated
SOUTH FORK GEOSCIENCES, PLLC Page 4
PO Box 1 275
NORTH BEND, WA 98045
425-831-2023 1 &NQr_vr�Eocar
Mione Short Plat January 11, 2017
19011 Olympic View Drive (Parcel # 00434600007800) Project #14012
Edmonds, Washington
erosion and/or instability, such as stream erosion, channel migration, or toe erosion from wave
action.
f. Consideration of the run -out hazard of landslide debris and/or the impacts of
landslide run -out on down slope properties.
Reams:
It is our opinion that the risk of deep-seated rotation failure of the slopes on the subject
property is low and the likelihood of landslide debris run -out is low. A slope "failure" would
more likely be erosion rills or minor, shallow debris flows from a very intense storm event. As
such, it is our opinion that the 10-foot buffer delineated will adequately mitigate any slide
debris run -out.
g. A study of slope stability including an analysis of proposed cuts, fills, and other
site grading;
ggmonse:
Due to the buffer applied to the landslide hazard areas, the site grading will not impact the
areas in question. Since the existing home will remain, the previously developed areas in or
near the "landslide hazard area" and associated buffers should be maintained as they have
been historically and it is our opinion that existing home and associated improvements should
be considered a "non -conforming legal use" and should not be encumbered by the landslide
hazard area or associated buffers.
h. Recommendations for building siting limitations; and
Res qr nse:
Besides the landslide hazard areas and associated buffers, it is our opinion that no other
building siting limitation are necessary. We have reviewed the referenced civil engineering
plans for the proposed development and it is our opinion that the locations of proposed
structures, utilities, and driveway will not create additional slope related risk. As stated in the
previous response, it is our opinion that the existing home and associated improvements
should not be encumbered by the landslide hazard areas or associated buffers.
i. An analysis or proposed surface and subsurface drainage, and the vulnerability of
the site to erosion;
Response:
The Vashon advance outwash sediments are conducive to stormwater infiltration. Due to their
high permeability, they generate less runoff than finer grained soils and are not specifically
prone to erosion. Stormwater infiltration trenches (Omega, Drainage & Grading Plan, Sheet 3)
and temporary erosion and sediment control measures (Omega, SWPPP, Sheet 2) are shown in
the referenced civil engineering plans. These infiltration trenches were sized based on the
recommendations set forth in our referenced Soil Assessment for Design Infiltration Rate letter
SOUTH FORK GEOSCIENCES, PLLC Page 5
PO Box 1 275
NORTH BEND, WA 98045
425-831-2023 1 ANQREWWC&�SF EO.QOM
Mione Short Plat
January 11, 2017
19011 Olympic View Drive (Parcel # 00434600007800) Project #14012
Edmonds, Washington
(SFG, April 2015). It is our opinion that these measures will perform adequately for the
proposed development.
3. Geotechnical Engineering Report. The technical information for a project within a
landslide hazard area shall include a geotechnical engineering report prepared by a
licensed engineer that presents engineering recommendations for the following:
a. Parameters for design of site improvements including appropriate foundations
and retaining structures. These should include allowable load and resistance
capacities for the bearing and lateral loads, installation considerations, and
estimates of settlement performance;
b. Recommendations for drainage and subdrainage improvements;
c. Earthwork recommendations including clearing and site preparation criteria, fill
placement and compaction criteria, temporary and permanent slope inclinations
and protection, and temporary excavation support, if necessary; and
d. Mitigation of adverse site conditions including slope stabilization measures and
seismically unstable soils, if appropriate;
Response:
These design parameters and recommendations were made in the referenced geotechnical
report for the project (SFG, April 2014).
4. Erosion and Sediment Control Plan. For any development proposal on a site containing
an erosion hazard area, an erosion and sediments control plan shall be required. The
erosion and sediment control plan shall be prepared in compliance with requirements
set forth in ECDC Chapter 18.30;
Response:
We have reviewed the erosion and sediment control plan prepared by Omega Engineering and
it is our opinion that this plan will perform adequately during construction, if properly
implemented.
G. Limited Report Requirements for Stable Erosion Hazard (details omitted for brevity)
Response:
Not applicable.
H. Seismic Hazard Areas (details and subsections omitted for brevity)
Response:
As stated in the referenced geotechnical report, there are no site specific seismic hazards (such
as liquefaction potential) that significantly impact the subject property or proposed
development. Recommendations for standard seismic considerations were made in the
referenced report and these recommendations are still valid.
SOUTH FOR GEOSCIENCES, PLLC Page 6
PO Box 1 275
NORTH BEND, WA 98045 In
425-831-2023 1 �aNr. Rr� w� gg'g, car .
Mione Short Plat January 11, 2017
19011 Olympic View Drive (Parcel # 00434600007800) Project #14012
Edmonds, Washington
Closure
We have enjoyed working with you on this project and are confident that the information
provided in this report will aid in the design of your project. If there are any questions about
this report, please feel free to contact us.
Sincerely,
Andrew L. Glandon, LEG, CPESC
Engineering Geologist / Owner
South Fork Geosciences, PLLC
Attachment: Landslide Hazard Areas and Buffers
References:
"RE: Planning review #3 of civil improvement plans for short plat (PLN20140075)" Mike From: Clugston, Associate
Planner, City of Edmonds, October 6, 2016
"Mione 2 Lot Short Plat, Sheets 1-5", omega Engineering, Inc., Job # 14-0608, April 20,2015
"Subject: Response to Planning Department 2nd Review Comments, Mione Short Plat, Parcel # 00434600007800,
19011 Olympic View Drive, Edmonds, Washington", South Fork Geosciences, PLLC, Project #14012, March 5, 2016
"Soil Assessment for Design Infiltration Rate, Mione Short Plat, Parcel # 00434600007800, 19011 Olympic View
Drive, Edmonds, Washington" South Fork Geosciences, Project #14012, April 19, 2015
"Subsurface Exploration, Geologic Hazards, and Preliminary Geotechnical Engineering Report, Mione Short Plat,
Parcel # 00434600007800, 19011 Olympic View Drive, Edmonds, Washington" South Fork Geosciences, Project
#14012, April 1, 2014
SOUTH FORK GEOSCIENCES, PLLC Page 7
PO Box 1 275
NORTH BEND, WA 98045 e
425 831 2023 1 ANF F E C F U- -QL- '0
Mione Short Plat
January 11, 2017
19011 Olympic View Drive (Parcel # 00434600007800)
Project #14012
Edmonds, Washington
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Landslide Hazard Areas and Buffers
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Prepared by: Andrew L. Glandon, LEG, CPESC
South Fork Geosciences, PLLC
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Linear Scale Valid
Source: Mione 2 Lot Short Plat, Sheet 1 of 6,'
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Omega Engineering
SOUTH FORK G EOSCIENCES, PLLC
Page
PO Box 1 2275
NORTH BEND, WA 98045
425-831-2023 I�rRlw, wee I rig, „m„ r
SOUTH FORK GEOSCIENCES
PO Box 1 275
NORTH BEND, WA 98045
(425) 831-2023
AGLANDON@COMCAST.NET
April 1, 2014
Project #: 14012
Subsurface Exploration, Geologic Hazards,
and Preliminary Geotec nical Engineering Report
Mione Short Plat
Parcel # 00434600007800
19011 Olympic View :give
Edmonds, Washington
Introduction
The purpose of this study was to gain subsurface information to be utilized in the feasibility and
permitting of a short plat subdivision of the subject property. It is our understanding that Chris
and Merin Mione intend to subdivide the property to create a new lot suitable for construction of
a single family residence on the western portion of the property. Authorization to proceed with
this study was provided by Chris Mione via e-mail on March 15, 2014. This report was prepared
for Mr. and Mrs. Mione and their agents for specific use in support of this project. The location
of the subject property is shown in the attached Vicinity Map. An excerpt of the site survey
prepared by Greene Land Surveying and the approximate locations of the subsurface
explorations logged for this study are shown on the attached Site and Exploration Plan.
Site Conditions
The subject property was located at 19011 Olympic View Drive in Edmonds, Washington. The
property was irregularly shaped and was approximately 300 feet in the east -west direction and
ranged from approximately 150 to 200 feet in the north -south direction. Based on information
from the Snohomish County Assessor website, the property was 1.23 acres in size. The property
sloped gently to moderately from the east down to the west. Based on a review of the site
survey, the slope on the west portion of the property was on the order of 2.5H:1 V
(Horizontal: Vertical) to 6H:1V. The slope immediately adjacent to Olympic View Drive was on
the order of 1H:1 V to 1.5H:IV, but this slope was obviously created by the road construction.
Based on the st�mrveyed elevations, there is approximately 65 feet of total relief ort the property.
The property was bordered on the west by Olyiiipic View Drive, and to the wilh,. south, and easT
by residential properties.
RECEIVED
SOUTH FORK GEOSCIENCES, PO BOX 1275, BEND, WA 98045, (425) 8 c 2017
DEVELOPMENT
COUNTER
The eastern portion of the property has an existing residence which is to remain on the site. The
western portion of the property where the new lot will be created will be the area of focus of this
report. A significant part of the western portion of the property had been cleared and was
covered with grass. There were some large Douglas fir trees and native forest vegetation near
the in the southwest corner of the property. We did not observe any signs of accelerated soil
erosion or soil movement during our site reconnaissance.
Subsurface Conditions
Subsurface conditions on the property were inferred from a visual reconnaissance of the property, a
review of the referenced geologic map (Minard, 1983) and three hand auger boring explorations
performed on the property. The explorations were logged by the undersigned licensed engineering
geologist and were immediately backfilled. The approximate locations of the subsurface
explorations are shown in the Site and Exploration Plan and the exploration logs are attached to this
report. Our interpretation of the native soils as Vashon advance outwash is in agreement with the
referenced geologic map. We also used subsurface information from a prior study on the adjacent
property to the south in our interpretation of the site geology (Johnson Residence, SFG, Jan, 2014).
Stratigraphy
Fill Soils
Fill soils were not encountered in the subsurface explorations performed for this study, but we
know that there are some existing fill soils associated with the sewer pipe and the water service
that extend up to the existing residence from Olympic View Drive. Based on the topography,
there also appears to be some fill soils in the area marked as "old road" on the site survey. We
have marked the approximate areas on the Site and Exploration Plan. Since the placement and
compaction of the fill soils is unknown, proposed structures should not be founded on existing
fill soils. The following section titled "Site Preparation and Site Grading" explains how to deal
with existing fill soils when encountered during construction.
Vashon Advance Outwash
Vashon advance outwash sediments were encountered in all of the hand auger borings logged for
this study from the ground surface to the total depth explored. The advance outwash sediments
generally consisted of medium dense to dense, fine to medium sand with gravel with varying
amounts of silt. Vashon advance outwash sediments are alluvial and fluvial sediments that were
deposited by meltwater streams and channels from the advancing Vashon glacial ice sheet. As
the glacial ice advanced, the advance outwash sediments were overridden and consolidated by
the glacial ice. As such, the advance outwash sediments are typically dense, relatively
permeable, and moisture insensitive due to the past glacial consolidation and the small amount of
silt and clay present. Due to their relatively coarse grain size distribution, the advance outwash
sediments are moderately resistant to erosion, except when subjected to concentrated water
flows.
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SOUTH FORK GEOSCIENCES, PO Box 1275, NORTH BEND, WA 98045, (425) 831-2023
Hydrology
There was no groundwater seepage observed in any of the explorations performed for this study.
Soil conditions observed were generally dry for the time of year, which is indicative of permeable
soils. Also, there were no signs of ponding water or flowing water observed. Groundwater
conditions are subject to change depending on seasonal weather conditions, but based on the
permeable advance outwash soils observed, we do not anticipate encountering adverse groundwater
conditions during construction.
Geologic Hazards
The following discussion of potential geologic hazards is based on the visual reconnaissance of the
site, the subsurface explorations, reviews of aerial photographs and regional topographic and
geologic maps of the area, and review of the applicable City of Edmonds Municipal Code and maps
that are available online.
Based on our comparison of the City of Edmonds Municipal Code to the topographic and geologic
features of the subject property, the property does not fulfill the criteria for an erosion hazard area,
landslide hazard area, or a seismic hazard area. The following two sections of this report will set
forth some basic erosion control best management practices for use in construction and will address
general seismic risks and design parameters associated with a seismic event.
Erosion Concerns
Though special mitigations are not necessary, a temporary erosion and sediment control (TESC) plan
should be created and implemented during site construction. It is our opinion that implementation of
a relatively basic erosion control plan will prevent off site sediment transport. The proper use of
"best management practices" (BMPs) should be utilized during earthwork activities to reduce the
potential for erosion and sediment transport off of the property. The following is a partial list of
BMPs that should be implemented:
s Phasing and scheduling earthwork activities during dry conditions
4 Rock construction entrances
Straw mulch
0 Plastic sheeting
Silt fence
O Keeping exposed soils and stockpiles covered when not actively worked
Establish temporary/permanent vegetation as soon as possible after foundation and utility
installation
Implementation of a TESC plan will likely be a requirement of the clearing and grading or building
permit. South Fork Geosciences is available to design the TESC plan and to provide any required
inspections during construction.
3
SOUTH FORK GEOSCIENCES, PO Box 1275, NORTH BEND, WA 98045, (425) 831-2023
Seismic Concerns
Generally, there are four types of potential geologic hazards associated with large seismic events:
1) ground rupture; 2) seismically induced landslides; 3) liquefaction; and 4) ground motion. The
potential for each of these to impact the site is discussed below.
Ground Rupture
Most large earthquakes in the Puget Sound area are sub -crustal events with epicenters ranging
from 50 to 70 kilometers in depth. The subject property is approximately 5 to 6 miles south of
the Southern Whidbey Island Fault Zone (SWIFZ). Though the subject property is near the
SWIFZ, to our knowledge, there are no signs of past ground rupture in the immediate vicinity of
the subject property. Based on the location of the subject property to the south of the known
fault zone and the lack of sufficient information to infer a recurrence interval for earthquakes on
the SWIFZ (Johnson, et al., 2004), it is our opinion that the probability of ground surface rupture
impacting the subject property is low, and no mitigations are necessary.
Seismically Induced Landslides
Due the topography and absence of steep slopes on the subject property, it is our opinion that the
potential for seismically induced slope failures on the site is low and no mitigations are
necessary.
Liquefaction
Liquefaction is a condition where loose, saturated, fine sandy soils lose their shear strength due
to rapid pore pressure build-up when subjected to high intensity cyclic loads, such as occur
during earthquakes. Due to the medium dense, well -graded, native soils encountered in the
subsurface explorations and the absence of adverse ground water conditions, the liquefaction
potential of this site is very low, and no mitigations are necessary.
Ground Motion
Seismic hazards that will affect the structure would likely be due to the intensity and duration of
the ground shaking. The structural design of the project should be consistent with 2009
International Building Code (2009 IBC) guidelines (Section 1613). Based on the results of our
subsurface explorations and our estimation of soil properties at depth utilizing available geologic
data, Site Class "C" as defined by Table 1613.5.2 of the IBC may be used for the design of the
project.
Prefiminar.y, Geotechnical Enineering Recommendations
Our exploration indicates that, from a geotechnical standpoint, the subject property is suitable for
the proposed subdivision of the property and the presumed future development, provided the
risks discussed are accepted and the recommendations contained herein are properly followed.
The near surface, native Vashon advance outwash sediments will be capable of providing
support for future structures. Since there are no current development plans for the new lot being
created, the following recommendations should be considered preliminary and any future
development plans should be reviewed by South Fork Geosciences prior to construction. South
4
SOUTH FORK GEOSCIENCES, PO Box 1275, NORTH BEND, WA 98045, (425) 831-2023
Fork Geosciences is available for further consultation with respect to specific design items, if
needed.
Site Preparation and Site Grading
It is likely that structural fill soils will be required to establish grades for the project. Any fill soil
placed beneath a foundation, retaining wall, or driveway/parking area must be constructed as a
structural fill. In areas that will provide structural support, any existing fill soils or loose soils
should be removed and replaced with structural fill as described below, or the fill soils should be
mitigated as described in later sections for specific applications.
Structural fill is defined as non -organic soil, placed in maximum 8-inch loose lifts, with each lift
being compacted to at least 95 percent of the maximum dry density, using the modified Proctor
test (ASTM: D1557) as the standard. Prior to placing any structural fill the exposed soils must
either be undisturbed or be compacted to a dense, non -yielding condition and be approved for
structural fill placement. In the case of utility trench filling, the backfill should be placed and
compacted in accordance with the applicable City of Edmonds or utility franchise standards.
If fill soil will be imported to the site, it should be free of organics and other deleterious material.
Mineral soils with more than 5 percent fines are considered to be moisture sensitive. The use of
moisture sensitive soils should be confined to dry weather conditions. The moisture condition of the
imported soil should be within a few percent of the optimum moisture content of the soil. Soils that
are too dry or too wet of the optimum moisture content to achieve suitable compaction will need to
be moisture conditioned prior to final compaction. The Vashon advance outwash sediments are not
moisture sensitive, but due to the relatively dry soil conditions observed, these soils may require the
addition of water to be placed as structural fill. In the case that moisture sensitive soils are used in
structural fills, this type of work should be limited to the summer months and good weather
conditions.
Placement and compaction of the structural fill should be monitored by a competent field
technician. In situ density testing should be performed during fill placement to verify proper
compaction of the fill soil. A sample of the planned structural fill soil will need to be available at
least 48 hours prior to fill placement for laboratory analysis.
Temporary cut slopes may be necessary to allow the installation of the foundations and for utility
installation. Temporary cut slopes should be limited to 1H:IV (Horizontal: Vertical) in the
existing fill soils and 1hH:1V in the Vashon advance outwash sediments. Stability of the cut
slopes is the responsibility of the on -site contractor and a safe work environment should be
maintained at all times. A trench shield or trench box should be used to install all utilities over 4
feet in depth or the sides of trenches and excavations should be sloped back per OSHA/WISHA
standards.
SOUTH FORK GEOSCIENCES, PO Box 1275, NORTH BEND, WA 98045, (425) 831-2023
Foundations
Spread footings may be used for building support when founded on medium dense native soils
or approved structural fill soils. To limit differential settlements between footings that bear on
both structural fill and medium dense to dense native soils, we recommend that an allowable
bearing pressure of 2,000 pounds per square foot (psf) be utilized for design purposes, including
both dead and live loads. An increase of one-third may be used for short-term wind or seismic
loading. Perimeter footings should be buried at least 18 inches into the surrounding soil for frost
protection; interior footings require only 12 inches burial. However, all footings must penetrate
to the prescribed bearing stratum, and no footing should be founded in or above loose, organic,
or existing fill soils.
It should be noted that the area bounded by lines extending downward at 1H:1V from any
footing must not intersect another footing or intersect a filled area that has not been compacted to
at least 95 percent of ASTM:D 1557. In addition, a 1.5H:1V line extending down from any
footing must not daylight because sloughing or raveling may eventually undermine the footing.
Thus, footings should not be placed near the edge of steps or near vertical cuts in the bearing
soils.
Anticipated settlements of footings founded on the medium dense native soils or approved rock
trenches should be less than 1 inch. Loose or disturbed surface soils, excessive moisture present or
poor foundation subgrade preparation could result in larger settlements. South Fork Geosciences
should perform a foundation bearing evaluation prior to concrete placement to verify that the design
bearing capacity of the soil has been attained. A foundation bearing evaluation will likely be
required by the City of Edmonds Building Department as a condition of the building permit.
Perimeter footing drains should be provided as discussed under the section titled Drainage
Considerations.
Lateral loads can be resisted by friction between the foundation and the supporting soils, and/or by
passive earth pressure acting on the buried portions of the foundations. The spread footings must be
backfilled with structural fill compacted to a dense, non -yielding condition to achieve the passive
resistance provided below. The structural fill must extend horizontally outward from the embedded
portion of the foundation a distance equal to at least three times the embedment depth over which the
passive resistance is applied. We recommend the following design parameters.
• Passive equivalent fluid = 300 pcf
• Coefficient of friction = 0.30
The above values are allowable and include a factor of safety of at least 1.5.
Lateral Earth Pressure
Cast -in -place, concrete foundation walls or retaining walls should be designed to resist "at -rest"
lateral soil pressure conditions if the concrete walls will not be free to yield laterally at the top.
Restrained walls should be designed to resist an "at -rest" equivalent fluid pressure of 55 pounds per
cubic foot (pcf). Concrete walls that are free to yield laterally at the top of the wall may be designed
6
SOUTH FORK GEOSCIENCES, PO Box 1275, NORTH BEND, WA 98045, (425) 831-2023
using an active soil pressure of 35 pcf. Surcharges from sloping backfill conditions or adjacent
structural loads should be added to the above lateral soil pressures. Full height drainage of
foundation walls will need to be installed to prevent hydrostatic pressures from acting on the walls,.
Retaining Walls
We presume that future development may require retaining walls to provide grade separation. South
Fork Geosciences should review all proposed retaining walls prior to construction.
Floor Support
We anticipate that a single-family home built on the new lot would utilize slab -on -grade floors or
a combination of slab -on -grade floors and structural/crawlspace floors. Slab -on -grade concrete
floors should be cast atop a prepared subgrade of structural fill soil compacted to a minimum of
90 percent of the modified Proctor maximum dry density. A capillary break with a minimum
thickness of 4 inches should be placed atop the prepared subgrade. The capillary break material
should be a gap graded material consisting of pea gravel, 3/4-inch washed drain rock, or clean
crushed rock with less than 5 percent fines (material passing the No.200 sieve). The capillary
break will reduce the potential for moisture wicking through the floor slab. A 10-mil thick
plastic vapor barrier should also be placed atop the capillary break material. All concrete
placement should follow the guidelines set forth by the American Concrete Institute (ACI).
In areas that structural/crawl space -type floors are used, provisions should be made to slope
internal crawlspace areas to lows that may be drained to the footing drain system around the
perimeter of the foundation to prevent the accumulation of standing water within the crawlspace
areas. The soil surface should be covered with a minimum 10-mil thick moisture barrier.
Drainage Considerations
A perimeter foundation drain should be established to protect the floor slab and internal crawlspace
areas from ground water intrusion. The level of the foundation drain should be set at, or slightly
below, the base of the footing elevation. The drain should consist of 4-inch diameter, rigid,
perforated, PVC drain pipe and should be set to allow for gravity discharge. The drainpipe should be
surrounded by a minimum of 6 inches of pea gravel or washed drain rock. Roof drains should not tie
into the footing drain but should be collected in a separate, tightline drain. The drain lines should be
set to discharge via gravity to a dispersion or infiltration area or to an approved stormwater drainage.
In addition, all footing stem walls that enclose conditioned space should be lined with a 12-inch-
thick (minimum) washed gravel blanket provided over the height of the wall that ties into the footing
drain. The washed gravel blanket should be ended one foot below the desired ground surface and the
top of the gravel should be covered with filter fabric. The remaining one foot should be filled with
compacted soil to reduce the amount of surface water entering the wall and footing drain system.
7
SOUTH FORK GEOSCIENCES, PO BOX 1275, NORTH BEND, WA 98045, (425) 831-2023
Site Drainage
We have not reviewed any plans for stormwater disposal at this time. The native, Vashon advance
outwash sediments are well suited for infiltration methods due to their relatively coarse grain size
distribution and lack of fine sediments. With the relatively large lot size and the gently sloping area
on the western portion of the property, we presume that infiltration methods such as a series of
drywells or infiltration trenches in the native sediments will be used to dispose of stormwater
generated from the site. Based on our visual assessment of the native Vashon advance outwash
soils, we believe that the soil would be classified as "sand" in the USDA Soil Textural Triangle.
South Fork Geosciences is available for additional consultation with respect to site drainage, if
necessary.
Conclusion
Our findings and recommendations provided in this report were prepared in accordance with
generally accepted principles of engineering geology and geotechnical engineering as practiced in
the Puget Sound area at the time this report was submitted. We make no other warranty, either
expressed or implied. Our observations, findings, and opinions are a means to identify and reduce
the inherent risks to the owner.
We are available to provide additional design recommendations and consultation throughout the
development of this project. Since there are no current development plans, the recommendations in
this report should be considered preliminary. South Fork Geosciences should be contacted to review
any architectural or grading plans and to provide additional geotechnical information and input prior
to construction. We are also available to provide construction monitoring services during
construction for earthwork quality control and to help ensure that the recommendations in this report
are properly implemented. We have enjoyed working with you and we are confident that this report
will aid in the design of your project. If there are any questions, please contact us at (425) 831-2023.
Sincerely,
Andrew L. Glandon, LEG, CPESC
Geologist / Owner
South Fork Geosciences
Jamey S. Battermann, PE
Geotechnical Engineer
_.... .....
8
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Attachments: Vicinity Map
Site and Exploration Plan
Exploration Pit Logs
References:
Minard, James P., "Geologic map of the Edmonds East and Part of the Edmonds West
Quadrangles, Washington" U.S. Geological Survey, Miscellaneous Field Studies Map MF-1541,
scale 1:24,000, 1983
Edmonds Municipal Code
littp://wvyw cdt�i�iotidsw,i.gov/ Tovet-nineiitli°ttles-ai�id-i•e gulitti tis.htr-til
City of Edmonds Maps
l'itt is//wvv"vwf.edinoti(iswii. ov/sei-vices/laIa is a-gis-data/services maps - III a . s.litInI
United States Department of Agriculture Natural Resources Conservation Service,
llttla:�/webs�ail��1°v�l�lcs.l.d��l�.l�:��v
Snohomish County Assessor Property Account Summary
ht(' )s://www.siic)c000i-Ly/}],O)talxl toil•c,,1555iiiii,lc03jwxb5vLiet:'/sari-cli.�i )x?.12iirceI twinber=00434
600007800
USGS Quaternary Faults Web Mapping Application
hilp A/carl"1111IL 1 alsgs. 1(—) ar uds/ l`aLlItsh11110
Johnson, S.Y., Blakely, R.J., Brocher, T.M., Sherrod, B.L., Kelsey, H.M., and Lidke, D.J.,
compilers, 2004, Fault number 572, Southern Whidbey Island fault zone, in Quaternary fault and
fold database of the United States: U.S. Geological Survey website,
lit a ://c rtliq uakes use s. Gov/hazards/g lets, accessed 01/10/2014 03:28 PM
"Subsurface Exploration, Geologic Hazards, and Geotechnical Engineering Report, Johnson
Residence, Parcel # 00434600007901, 9527 190th Place SW, Edmonds, Washington" South
Fork Geosciences, Project #12058, January, 14, 2014
9
SOUTH FORK GEOSCIENCES, PO Box 1275, NORTH BEND, WA 98045, (425) 831-2023
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PO Box 1 275
NORTH BEND, WA 98045
(425) 831-2023
AGLANDON@COMCAST.NET
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Project #14012
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Edmonds, WA
Date: 3-28-2014
Depth Number: 1113-1
nt
0 Sod (0-2")
Vashon Advance Outwash
loose to medium dense, moist, black brown to
light brown, fine to medium SAND with gravel
1 and silt (SP-SM)
becomes medium dense @ 1.5ft
2 d Idense, moist, tan -light brown, fine to medium
SAND with gravel, trace silt (SP)
3 Total Depth = 3.Oft, Refusal due to gravels
No seepage observed
No caving observed
4
5
6
7
The subsurface conditions shown on this field log represent our observations at the time and location of excavation, modified by geologic interpretation
and judgment, and where noted, by engineering analysis and laboratory testing The conditions shown may not be representative of conditions at other
times South Fork Geosciences will not be responsible for use or interpretation by others of information presented on these logs
SOUTH FORK GEOSCIENCES
PO Box 1275
NORTH BEND, WA 98045
Project # 14012 PHONE: (425) 831-2023
Mione Short Plat
Edmonds, WA
Date: 3-28-2014
Depth Number:
L Ut
0 Forest Duff/Topsoil (04")
Vashon Advance Outwash
loose to medium dense, moist, light brown to
brown, fine to medium SAND with gravel and
silt (SP-SM)
2 11 roots present to 2ft, medium dense @ 2ft
medium dense to dense, moist, gray -light
brown, fine to medium SAND with gravel, trace
3 silt (SP)
Total Depth = 3.5ft, Refusal due to gravels
No seepage observed
4 No caving observed
5
6
7
The subsurface conditions shown on this field log represent our observations at the time and location of excavation, modified by geologic interpretation
and judgment, and where noted, by engineering analysis and laboratory testing. The conditions shown may not be representative of conditions at other
times, South Fork Geosciences will not be responsible for use or interpretation by others of information presented on these logs,
Project # 14012
SOUTH FORK GEOSCIENCES
PO Box 1275
NORTH BEND, WA 98045
PHONE: (425) 831-2023
Depth
0
2
3
a
M
6
7
Mione Short Plat
Edmonds, WA
Date: 3-28-2014
Number: H13-3
Vashon Advance Outwash
medium dense to dense, moist, gray -light
brown, fine to medium SAND with gravel, trace
Total Depth = 1.0ft
No seepage observed
No caving observed
Located in road cut exposure
-confirmed cut into native sediments
Approximately 4 to 5 feet below base of wood
The subsurface conditions shown on this field log represent our observations at the time and location of excavation, modified by geologic interpretation
andjudgment, and where noted, by engineering analysis and laboratory testing, The conditions shown may not be representative of conditions at other
times, South Fork Geosciences will not be responsible for use or interpretation by others of information presented on these logs,
SOUTH FORK GEOSCIENCEs
PO Box 1275
NORTH BEND, WA 98045
Project # 14012 PHONE: (425) 831-2023