509 9TH AVE N.PDFiiiiii lill 11
9873
509 9TH AVE N
ADDR1ESS: AJ
TAX AC�,-.',"-'Lj'NT/PARCEL NUMBER:— Lo .3 4? 010
BUILDING PERMIT (NEW STRUCTURE): 0/4/0
COVENANTS (RECORDED) FOR:
CRITICAL AREAS DETERMINATION: F] Conditional Waiver Study Required E] Waiver
DISCRETIONARY PERMIT #'S:
DRAINAGE PLAN DATED:--�q
PARKING AGREEMENTS DATED:
EASEMENT(S) RECORDED FOR:Wt-0tW Vkh
PERMITS (OTHER
PLANNING DATA CHECKLIST DATED: /1/6/09
SCALED PLOT PLAN DATED:
f
SEWER LID FEE $:
SHORT PLAT FILE:
SIDE SEWER AS BUILT DATED:
SIDE SEWER PERMIT(S)
GEOTECH REPORT DATED: I
STREET USE / ENCROACHMENT PERMIT
WATER METER TAP CARD DATED:
LID #:
LOT: BLOCK:
IQ cJ
LATEMP\DST's\Forms\Street File Cheeklist.doc
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Eric Thuesen Homes LLC- Scale r =20" AA� rcj-AdtCJA�
sM 9P Ave N. Ii0-00
Edmonds, WA. 98020
BUIL U
CRY OF EDIAONDS- %
APAIOVEU AS NOTED
Al BffiENGLNEE81 19,786 SF
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Existing Residence Pad 2815's.f. (bu 2008
-ExistingGarage 424sf. (built2OO8)
Existing Deck: 144 sf. (built 2008) -
Existing Covered Porch 34 s.f. (built 2008)
Existing Driveway 1067 s.f. (built 2008)
Existing Caban'a' 427 s.f. (built 2013)
Proposed Hot Tub and walkway 272 s.f.'
T^I-%I rnwar2fr= F,
0 '� 0
South hot tub wall shall be set
back 10' from south property line.
15 t 0 2-0 (3 ((-7_S--
Zone g�— 1-2- Comer Flag_2<-
Setbacks
ReQuired
Actual
0
at Ffont /,j __
10
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to
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Per aCDC I 66.20.04O.C. the hot tub patio surround
rnay extend 3.33' into the required 10' setback
/3 distance of the required I 0� setback or 3,33')
Non -retaining wall/fence shall be no greater than 6' in
height from average original grade to the top of the fence
OVED BY PLAN NG
t -2-7 N
I* City of Edmonds 1$
Critical Area Notice of Decision
Applicant:
Vve-seA
Property Owner:
Critical Area File #.-
CIM 70 o 100 6 -7
Pen -nit Number:
dt d -2-0/ 3- (2j-
Site Location:
CI 7 -o� A-J� /u/
Parcel Number:
-Z -7 o3 2 100 Z �- /,�,c
Project Descriptio n:
- �- �,6 a i*n Am ct " " "( )-a-Z 5 � 11
?0/fc�
F-I Conditional Waiver. No critical area report is required for the project describe8 above.
IV71 (3-/ . 7 0
I . There will be no alteration of a Critical Area or its required buffer. eocl&6p� :3
2. The proposal is an allowed activity pursuant to ECDC 23.40.220, 23.50.220, angor
23.80.040.
3. The proposal is exempt pursuant to ECDC 23.40.230.
F-I Erosion Hazard. Project is within erosion hazard area. Applicant must prepare an erosion and
sediment control plan in compliance with ECDC 18.30.
Z7Critical Area Report Required'. The proposed project is within a critical area and/or a critical area
buffer and a critical area report is required. A critical area report has been submitted and evaluated
for compliance with the following criteria pursuant to ECDC 23.40.160:
I . The proposal minimizes the impact on critical areas in accordance with ECDC 23.40-.120,
Mitigation sequencing;
2. The proposal does not pose an unreasonable threat to the public health, safety, or welfare
on or off 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. 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. _,�L The proposal is consistent with other applicable regulations and standards.
F-1 Unfavorable Critical Area Decision. The proposed project is not exempt or does not adequately
mitigate its impacts on critical areas and/or does not comply with the criteria in ECDC 23.40.160 and
the provisions 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 from the criteria in' ECDC 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).
4(c/gs , LUI\
Reviewer
4-- `9 /
Signature
-7 /1 Y
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 procedure, if any,
for the permit or approval involved.
Revised 12/16/2010
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ILITY EASEMENT ON
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cy 3 ;& BUILDING VE—PAITIMEN'
T S!' OF EDMONDS
ADJUS
SD AS 1_70EU
20' UTILITY EASEMENT FOR WALL Line Type Area (square feet)
ON LOT 2 TO BENEFIT LOT 1 1 1
Non -Regulated
V Q PI AN ING Zone Comer Fla
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WORM
107.0±EGE Setbacks -,guired Actu
WEST WALL
Replaced
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Front _iUy_L0_
jo�110* 3. New (Post 1977) 44 4 444 4 4
Total Regulated Impervious Area
-r* far"__ INSPECTION'S REQD. to 4.
SE VER '7� 17112- Sides
CALL 425-771-0220 pa. tr4a Real- 6 Mitigation required if in excess of 2000sf
Date, 5. Total Area Mitigated by E3dsdng Stormwater Management System(s)
Other -A r-)
36 35 34 33 6. Regulated Area Not Yet Mitigated
C-
V Per ECb(— fe-5
7. Area Proposed Ao be Mitigated by Low Impact Development Techniques
RES1% AACtA/ tricrOAJI 9.;03 -1AAx1AA.V#1 8. Area Proposed to be Mitigated through Conventional SWM Techniques
RESUB
MAY 14 2012 V IT 4017 *Detention waiver approved by Don Fien'e 7/17/07
MAR 3 0 2012
BUILDING DEP�Rc�-MENT Refer to S-05-09. Discharge directly into the regional
CITY OF EbMONDS BUILDING DEPARf-MENT OWNER/CONTRA(I%PTOR IS RESPONSIBLE Detention fa cility just west of the site which discharges
CITY OF EDMONDS FOR EROSION CQNTROL AND DAMAGE Directly to Puget Sound. -BLD 2-o I (- C) -7 T�_
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16 City of Edmonds 0
Critical Area Notice of Decision
Applicant:
Property Owner:
Ue's e-k—
Critical Area File # .
CeA
Permit Number:
Zo 10 -7 -7-S—
Site Location:
50 � � IV; SI �,+Farcel
Nvinber:
'AJ, - /V
770-3-2-qOO'L -)0/
12.70Z2VOoZZ-S-100
Project Description:
Fe lyVif-L7\�- di(-f eirc(fa Coad )� ccd�a
F� Conditional Waiver. No critical area report is required for the project described above.
There will be no alteration of a�Critical Area or its required buffer.
The proposal is an �Ilowed activity pursuant to ECDC 23.40.220, 23.50.220, and/or
23.80.040.
The proposal is exempt pursuant to ECDC 23.40.230.
F-I Erosion Hazard. Pro9ect is within erosion hazard area. Applicant must prepare an erosion and
sediment control plan in compliance with ECDC 18.30.
Critical Area Report Require d. The proposed project is within a critical area and/or a critical area
buffer and a critical area report is required. A critical area report has been submitted and evaluated
for compliance with the following criteria pursuant to ECDC 23.40.160:
I The proposal minimizes the impact on critical areas in accordance with ECDC 23.40-.120,
Mitigation sequencing;
2. The proposal does not pose an unreasonable threat to the public health, safety, or welfare
on or off 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 accordancew.ith ECDC
23.40. 110, Mitigation requirements.
5. 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.
F-I Unfavorable Critical Area Decision. The proposed project is not exempt or does not adequately
mitigate its impacts on critical areas and/or does not comply with the criteria in ECDC 23.40.160 and
the provisions 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 from the criteria in' ECDC 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. Criti cal Area specific condition(s) have been applied to the permit number referenced
above. See referenced permit number for specific condition(s).
C
Date
Reviewer Signaturne
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 procedure, if any,
for the permit or approval involved.
Revised 12/16/2010
PLANNING DATA
SINGLE FAMILY RESIDENTIAL
11 S TREE T FILE_
Name: S �A CID z 1 -7 Q 3-2- -100 5 10
- 0 )
Date: 2
0 (1 12
IL
14-, /tj
Site Address:
---
Plan Check 2,::�'(t!
Project Description:
Lo, ct,,&,
Reduced Site Plan Provided: (0/ NO) -1
Zoning:
Map Page:
Corner Lot: (YES 09 1 Flag Lot: ((LE!
Critical Areas Determination 9:Z0C)l 10 /11, 7-
kff-Study Required
Waiver
SEPA Determination:
VExempt
El Needed (for over 500 cubic yards of grading)
0 Fee 0 Checklist 0 APO List with notarized form
Regulted S?tbacks
Street:
o
Side-
1 5 /0
Rear:
Actual Setback5
Street: z-3
Side:
Side: /0
M Detached Structures:
ok,-
ELRockeries: UAXA
Fences/Trellises:
Bay Windows/Projecting Modulation:
AKLStairs/Deck:
Hefght
Datum Point: 410 V
Datum Elevation: f
Maximum Height Allowed:
ctual Height:4#.-�� q- 7_5�co 1,60,
Other
Parking Required: /61'k-
Parking Provided: /V74
Lot Area:
11-736*
Maximum Lot Coverage: 35% Proposed
Lot Coverage Calculations: kjc/st, vlqie,� 6- 9 cq,6ao,4 4L 6 &,o 6
ADU Created: (YES /tQ)
Subdi si(
Legal Nonconforming Land Use Determination [ssued: �Y'Es
comments
I/ V VU L-CAt
t
01 iL�Plan Review By: 7 It -7 /(L- ,, )"", .,,-,,6.doc
Z-
D/
40.
0 City of Edmonds 41
Critical Area Notice of Decision
Applicant:
—T� V'e�C&
Property Owner:
�-Ht ueSeA
Critical Area File #:
7-00(-o66-7
Permit Number:
86 0 — 2-0 f 0 7 -7E-
Site Location:
7 ffue- Al
Parcel Number:
-2::3 15 75 =t
Project Descriptio n:
F-� Conditional Waiver. No critical area report is required for the project described above.
There will be no alteration of a -Critical Area or its required buffer.
The proposal is an �Ilowed activity pursuant to ECDC 23.40.220, 23.50.220, and/or
23.80.040.
The proposal is exempt pursuant to ECDC 23.40.230.
Erosion Hazard. Project is within erosion hazard area. Applicant must prepare an erosion and
sediment control plan in compliance with ECDC 18.30.
�f—Critical Area Report Required. The proposed project is within a critical area and/or a critical area
buffer and a critical area report is required. A critical 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. The proposal does not pose an unreasonable threat to the public health, safety, or welfare
on or off 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 w,ith ECDC
23.40.110, Mitigation requirements.
5. 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.
F-I Unfavorable Critical Area Decision. The proposed project is not exempt or does not adequately
mitigate its impacts on critical areas and/or does not comply with the criteria in ECDC 23.40.160 and
the provisions 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 from the criteria ih ECDC 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.
F-I Conditions. Criti cal Area specific condition(s) have been applied to the permit number referenced
above. See referenced permit number for specific condition(s).
'7611" mpf�
Reviewer Signature*-' 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 procedure, if any,
for the permit or approval involved.
Revised 1206/2010
CITY OF EDMONDS
121 51h Avenue North, Edmonds WA 98020
Phone: 425.771.0220 * Fax: 425.771.0221 9 Web: www.edmondswa.gov
DEVELOPMENT SERVICES DEPARTMENT 9 PLANNING DIVISION
J 12 C. I s 9 V
Critical Areas. ReconnaissaInce Report Update
Critical Areas File Number
Determination
-Site Location
Tax Account Number
Property Owner
Applicant
Critical Areas Present
CRA20010067
Study Required
th
.5-69 9,-. A ven.ue'North
-L -7 0-S-2140
0
L
Eric Thuesen 7/11JA -Z-
NIA
2 Geologically Hazardous Areas
2 Erosion Hazard Area
2 Landslide Hazard Area
THIS PARCEL WAS PREVIOUSLY IDENTIFIED AS A'STEEP SLOPE
HAZARD AREA' IN 2001. HOWEVER, THE CRITICAL AREAS
CODE UPDATE OF 2005 REQUIRES REASSESSMENT OF THE
ORIGINAL DETERMINATION.
Site Description
During review and inspection of the subject site, it was found that the site may contain (or be adjacent to) critical
areas, including Geologically Hazardous Areas (Erosion and/or Landslide Hazard Areas), pursuant to Chapters
23.40 and 23.80 of the Edmonds Community Development Code (ECDC). Geologically hazardous areas include
areas susceptible to erosion, land sliding, earthquake, or other geological events. They pose a threat to the health
and safety of citizens when incompatible development is sited in areas of significant hazard. Such incompatible
development may not only place itself at risk; but also may increase the hazard to surrounding development and
use. Cited sections of the Edmonds Community Development Code can be found on the City of Edmonds website
at www.edmondswa.gov.
th
The associated LiDAR map indicates that the parcel generally slopes down from east to west toward 8 Avenue.
The eastern portion of the lot where the existing h ouse is located is more level but the grade falls. away steeply to
the west of the house. This portion of the slope exceeds 40% (at approximately 50%) while portions of the eastern
area range from 15-25%. Soils on the parcel are identified primarily as Alderwood Urban land compl ex (8% - 15%
slope). As a result, the slopes in excess of 15�o' are classified as a potential erosion hazards and the portion that
exceeds 40% is a potential landslide hazard area.
Allowed Activities & Exempt Proposals
Certain activities are allowed in or near critical area buffers as specified irf ECDC 23.40.220. Similarly, certain
development proposal s may be exempt from Critical Areas requirements (ECDC 23.40.230). If you have any
questions about whether your proposed development qualifies as an allowed or exempt activity, please contact
a Plannerfor more information.
General Report Requirements
Critical Areas Reports identify, classify and delineate any areas on or adjacent to the subject property that may
qualify as critical areas. They also assess these areas and identify any potential impacts resulting from your specific
development proposal. if a specific development proposal results in an alteration to a critical area the critical
areas report will also contain a mitigation plan. You have the option of completing the portion of the study that
classifies and delineates the critical areas and waiting until you have a specific development proposal.to complete
the study. You may also choose submit the entire study with your specific development application. Please review
the minimum report requirements for all types of Critical Areas which are listed in ECDC 23.40.09O.D. There are
additional report requirements for different types of critical areas (see below). Note that it is important for the
report to be prepared by a qualified professional as defined in the ordinance. There are options on ho wto
complete a critical areas study and an approved list of consultants that you may choose from -You may contact the
Planning Division for more information. General Mitigation Requirements for all Critical Areas are discussed in
ECDC 23.40.110 through 23.40.140.
Erosion Hazard Areas
Erosion Hazard areas include Alderwood and Everett series soils on slopes of 1 ' 5 percent or greater, among others.
Landslide Hazard Areas are further defined in ECDC 23.80.020.A. In addition to the general requirements for
Critical Areas reports referenced above, specific Critical Area report requirements for Erosion Hazard Areas (which
are one of the Geologically Hazardous Areas) are provided in ECDC 23.80.050.
Note that Stable Erosion Hazard Areas may have limited report requirements at the director's discretion. At a
minimum an erosion and sediment control plan prepared in compliance with, the requirements in ECDC Chapter
18.30 shall be required.
Development is restricted within an Erosion Hazard Area and must meet additional criteria. For erosion hazard
areas with suitable slope stability, an erosion and sediment control plan prepared in compliance ECDC 18.30 will be
considered to meet the Critical Areas "Study Required" determination. The determination of "suitable slope
sta i bility" will be made by both the Planning and Engineering divisions of the City of Edmonds. In areas where the
slope stability is not suitable, projects within Erosion Hazard Areas will require a report by a licensed Geotechnical
Engineer -or other qualified, professional. Note that it is important for the report to be prepared by a qualified
professional as defined in the ordinance. Report requirements are given in ECDC 23.80.050, and more generally in
ECDC 23.40.09O.D. Development standards are given in ECDC 23.80.060 and 23.80.070.
Page 12
Landslide Hazard- Areas
Development is restricted within a Landslide Hazard Area and its buffer. Projects that will intrude into these areas
will require a report by a licensed Geotechnical Engineer. Geologically hazardous areas include areas susceptible
to erosion, land sliding, earthquake, or other geological events. They pose a threat to the health and safety of
citizens when incompatible development is sited in areas of significant haza rd. Such incompatible development
may not only place itself at risk, but also may increase the hazard to surrounding development and use.
The criteria that are applied depend on the amount that the buffer is reduced. The bu ffer can be reduced to a
minimum of ten (10) feet (with an additional 15' building setback per ECDC 23.40.280).if a report is prepared that
meets the standards listed in ECDC 23.80.050). The alteration must also meet the requirements listed ECDC
23.80.060. In addition, proposals to reduce the buffer to less than ten (10) feet must comply with the design
standards listed in ECDC 23.80.070.A.3. Development is.restricted within a Landslide Hazard Area and its buffer.
Projects that will intrude into these areas will require a report by a licensed Geotechnical Engineer.
Determination: Study Required
This review applies to the entire subject parcel. Depending on the location and project proposed relative to the
identified criticalareas, certain studies and reports may be required. Please contact the Planning Division at-
425.771.0220 if and when you have a specific development proposalfor this site in order to discuss the various
permits. that will be required.
Mike Clugston, Associate Planner - Mk' �� April 6, 2012
Name, Title SignatuW Date
Page 13
'X
10�
4" C/O,
2'FROM HOUSE
ll�
4" SDR35,
2'DEEP
15091 STREET FILE
I
Z.) 4,� /3'DEEP
0
STORM LINE
NOTICE: NO WARRANTY OF ACCURACY. The information shown on
the attached map was compiled for use by the City of Edmonds, its
employees and consultants. The City of Edmonds does not warrant the
accuracy of anything set forth on the map. Any person or entity
requesting a copy should conduct an independent inquiry regarding the
information shown on the map, including, but.not limited to, the location
of any sewer stub shown. Such sewer stubs may or may not exist and
may or may not exist at the location shown. Neither the City of Edmonds
nor its employees or officers shall be liable for the information given on
this map, nor for any oral representation provided based upon said map.
0 F E.D* CITY OF
0
� I ADDRESS:
SHED
REAR OF HOUSE
8-
4
25'
EDMONDS SIDE SEWER AS-BUIJ
PERMIT
Q 0), 509 9TH AVE N No- ENG 20060235
CONTRACTOR: HOMEOWNER:
CUSTOM HOMES I ERIC THEUSEN
DATEINSPECTED: INSPECTED BY: DATE DRAWN:
5/23/06 1 E. SIBREL 1 10/16/06
NTS
ABILA/SHIU
City of Edmonds
Critical Areas Determination
Project Specific Waiver of WETLAND STUDY Requirement
Determination CA-01-067
Applicant: Eric Thuesen
Project Name: I Thuesen NSFR I Permit Number: I PC-04-476 I
Site Location: 1 509 91h Ave. N. I Property Tax Acct #: 1 242703220600 1
Project Description:
Construct one new single-family residence and one new detached
garage. Wetland study requirement waived due to distance from
wetland.
Waiver Criteria (all criteria must be found to apply):
X There will be no alteration of the Critical Area or its required buffers;
X The development proposal will not impact the Critical Area in a manner contrary to
the goals, purposes, objectives and requirements of the Critical Areas ordinance;
X The development proposal meets the minimum standards of the Critical Areas
ordinance;
X The above findings are based on the following conditions of approval:
This conditional waiver is only for the construction of one new single-family
residence and one new detached garage as described above and shown on the
attached site plan. Any additional work and future projects will require a separate
determination regarding study requirements.
2. A building permit is required for all work.
Based on the above findings and conditions, the requirement for a Critical Areas Study
associated with this development permit is hereby Waived, as authorized by Chapter 20.15B.040
(A) of the Edmonds Community Development Code.
Ross C. Beckley � �& / November 15, 2004
Name Signature 4� Date
NORTH
5CALE: V 2CY-CY'
Cv
4d 9VI
Z
c
�PLOT PLAJ,4
MAXIMUM 13UILDING HEIGHT5:
HOU!5E
A 152.8'
165.4'
144.4'
149.9'
612.5 /4 = 15-3.12
+ 25'= 176-121.5= MAX ROOF ELEV.
MAXIMUM DUILDING HEiGHT6:
DETACHED GARAGE; �
E 1 (53 5
F 1 (538. 0'
�� 165.4'
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Dennis M. Bruce,' RL.
M.S.C.E., M.B.A. Gectechnicall/Clvd Engineer
OCT - 8 2004
PERA41T COL/NTER
Mr. & Mrs. Wolgamott
503 9h Ave. N
Edmonds, WA 98020
October 24, 2001
Subject: Preliminary Geotechnical Evaluation / Wolgamott Property
503 9hAve. N, Edmonds, Washington I .
This engineering report presents the results of a preliminary geotechnical
evaluation of the Wolgamott property located at 503 9th Ave. N, Edmonds, Washington.
This evaluation was made at the request of owners and real estate broker, Dan
Tomasek.
REFERENCES:
Property map and slope study by LSA dated May 23, 2001
Site photographs
BACKGROUND:
It is understood that the total overall property contains the existing Wolgamott
residence (503 9th Ave. N) as well as a long, rectangular piece of property that runs
westerly down slope to 8th Ave. N (see photographs). It is understood that the existing
residence is to remain, with three (3) future single-family residences to be built on the
lower (westerly) property. The lower piece of property (containing the future 3 new
residences) is approximately 110 feet wide by approximately 400 feet long. Currently,
this lower piece of property contains a historic tennis court, small concrete access drive,
and minor landscaping. The remainder of the lower property contains mature trees,
brush and grasses.
The primary geotechnical feature affecting development is slopes. The
southeast comer of the lower property contains a high point (elevation approximately
169). The western edge of the property (abutting 8th Ave. N) contains a low spot
(approximately elevation 93).
SOILS - FOUNDATIONS - SITE DEVELOPMENT - INSPECTION - DRAINAGE - DESIGN& PERMIT - LEGAL
P.O. Box 55502 - Shoreline, Washington 98155 - (206) 546-9217 - FAX 546-8442
r
Mr. & Mrs. Wolgamo
October 24, 2001
Page 2
PRELIMINARY EVALUATION:
This engineer performed an initial visual geotechnical evaluation of the property
on August 18, 2001 and subsequent inspection using a hand soil probe on September
27,2001.
Visual evaluation of the property revealed no evidence of any geotechnical
distress: no slides, no sloughing, no soil tension cracks nor any evidence of significant
erosional degradation.
It is understood that one new proposed residence will occupy the portion of the
property where the current tennis court exists.
The tennis court reveals no evidence of any geotechnical distress (other than
years of non-use and slight slab cracking). Obviously, the tennis court area provides a
relatively flat house location site. The use of a hand soil probe verified relatively
shallow (less than 18 inches) dense, sub grade soils.
It is understood that the remaining two future residences will be accessed
through the bottom (off 8 th Ave. N). Walking / exploring the lower portions of the th
property did verify the topographic map indications of less steep topography towards 8
Ave. N. The use of a hand soil probe verified the presence of dense, native sub grade
soils capable of providing a minimum of 2,000 p.s.f. bearing capacity.
CONCLUSIONS / RECOMMENDATIONS:
Based on the findings of this engineer's preliminary geotechnical evaluation and'
experience with nearby properties, the following are concluded and recommended:
The proposed 3'future single-family residences on the lower portion of the
Wolgamott property are geotechnically viable.
The slopes present do not pose adverse geotechnical impacts to the
development of the proposed 3 houses.
Additional specific geotechnical investigations (test pits, soil analysis, foundation
recommendations, etc.) are required to proceed with development of the
proposed 3 houses.
This engineer observed no adverse drainage or water conditions precluding the
proposed development of 3 new houses.
Nov 15 04 013:31a- D-.- Bruce, P.E. 206-549-L8442
P. I
Dennis M. Bruce, P.E.'
A4.S.C.E., M.B.A. Geotechnical /Civil Engineir
November 12, 2004
City of Edmonds
cJo Eric Thuesen Custom Home
18333 Be PL W.
Edmonds, WA 98026
Subject: Geotechnical Review — Site Plan
Proposed New Residence SW 99h Ave. North
Edmonds, Washington
This engineering report presents the results of a geotechnical review o
property and site plan for the proposed new residenoe by Thuesen Cust:
Homes.
REFERENCES:
• Preliminary geotechnical report by D. Bruce, P.E. October 21, 2001
• Soil test pit photographs dated September 4, 2002
• Site Plan for proposed for new residence by Thuesen homes
BACKGROUND:
This engineer has provided geotechnical services for potential buyers and
developers of the overall property at 503 9th Ave. N.
The soil test pits where dug on September 4, 2002 in the vicinity of the
proposed new home by Thuesen Custom Homes.
This engineer vertfied very dense native sands with gravels at shallow
footing depths.
PROPOSED NEW.RESIDENCE:
This engineer has reviewed the attached sit plan by Thuesen Custom
Homes for the new residence to be located in the aTennis courf zone.
The topography for the site has been performed by LSA and defines the
top-of4ope. See survey map.
SOILS - FOUNDA 77ONS - SITE DEVa OPMEW - INSPEC77ON - DRAINAGE - OESION J PERMIT - LEGAL
P.O. Box 55502 - Shoreline, WA 98155 - (206) 546-9217 - FAX (206) 546-8442
Nov 15 04 08:31a
City of Edmonds
11-9-04
Page 2 of 2
D. Bruce, P.E. 206-546-U44e P
0
The proposed site plan for the now residence will result in the foundation
to be set back 25 feet from the top -of -steep slope boundary.
The reduction of the buffer from 50 feet to 25 feet will have no adverse impact on
the site, the public, or any private party, gggiect to onsite geotechnical
inspections by this engineer.
SUMMARY:
The proposed new residence and location per sit e plan ( with 25 foot set
back from top of slope ) is geotechnically ppproved subject to onsite -
inspections bv this engineer.
if there are any questions, do not hesitate to call.
Dennis M. Bruce, P.E.
Geotechnical / Civil Engineer
DMB:Imb
fem-as -afff—z n6z]
a
Mr. & Mrs. Wolgamott
October 24, 2001
Page 3
If there are any questions, do not hesitate to call.
I EXPIRES
DMB:abj
Dennis M. Bruce, P.E.
Geotechnical / Civil Engineer
09 IVII 5. vvoigamott
October 24, 2001
-Page 2 0
PRELIMINARY EVALUATION:
This engineer performed an initial visual geotechnical evaluation of th I e property
on August 18, 2001 and subsequent inspection using a hand soil probe on September
27, 2001.
Visual evaluation of the property revealed no evidence of any geotechnical
distress: no slides, no sloughing, no soil tension cracks nor any evidence of significant
erosional degradation.
It is understood that one new proposed residence will occupy the portion *of the
property where the current tennis court exists.
The tennis court. reveals no evidence of any geotechnical distress (other than
years of non-use and slight slab cracking). Obviously, the tennis court area provides a
relatively flat house location site. The use of a hand soil probe verified relatively
shallow (less than 18 inches) dense, sub grade soils.
It is understood that the remaining two future residences will be accessed
through the bottom (off 8th Ave. N). Walking / exploring the lower portions of the
property did verity the topographic map indications of less steep topography towards 8th
Ave. N. The use of a hand soil probe verified the presence of dense, native sub grade
soils capable of providing a minimum of 2,000 p.s.f. bearing capa *
city.
CONCLUSIONS / RECOMMENDATIONS:
Based on the findings of this engineer's preliminary geotechnical evaluation and
experience with nearby properties, the following are concluded and recommended:
The proposed 3 future single-family residences on the lower portion of the
Wolgamott property are -Geotechnically viable.
The slopes present do not pose adverse geotechnical impacts to the
development of the proposed 3 houses.
Additional specific geotechnical investigations (test pits, soil analysis, foundation
recommendations, etc.) are reguired to proceed with development of the
proposed 3 houses.
This engineer observed no adverse drainage or water conditions precluding the
proposed development of 3 new houses.
Mr. & Mrs. Wolgamott
October 24, 2001
*Page 3
If there are any questions, do not hesitate to call.
I EXPIRES 1ZW -A 00 1 1
DMB:abj
Dennis M. Bruce, P.E.
Geotechpical / Civil Engineer
Witical Areas Checklis-0 CA File No:— Cq -7
Site hiformation (soils/ topography/ hydrology/ vege& n)
Site Address/ Location: J-�Vi�_Xk
2. Property Tax Account Number:
3. Approximate Site Size (acres or square feet):
4. Is this site currently developed? _ yes; no.
if 'yes; how is site developed?
5. Describe the general site topography. Check all that apply.
Flat: less than 5-feet elevation change over entire site.
Rolling: slopes on site generally less than 15% (a vertical rise of 10-feet over a horizontal
distance of 66-feet).
Hilly: slopes present on site of more th an 15% and less than 30% ( a vertical rise of 10-feet
over a horizontal distance of 33 to 66-feet).
Steep: grades of greater than 30% present on site (a vertical rise of 10-feet over a horizontal
distance of less than 33-feet).
Other (please describe):
6. Site contains areas of year-round standing water: Approx. Depth:
7. Site contains areas of seasonal standing water: - NO Approx. Depth:
What season(s) of the year?
8. Site is in the floodway nC floodplain _ of a water course.
9. Site contains a creek or an area where water flows across the grounds surface? Flows are year-round?
Flows are seasonal? (What time of year?
10. Site is primarily: forested meadow ;shrubs mixed
urban landscaped (lawnshrubs etc)
11. Obvious wetland is present on site: V,�,D
For City Staff Use Only
1. Plan Check Number, if applicable?
2. Site is Zoned?. P�
3. SCS mapped soil type(s)? !-%qjx:-,",j
4. Critical Areas inventory or C.A. map indicates Critical Area on site? qp.
5. Site within designated earth subsidence landslide hazard area?
DETERMINATION
SrUDY REQUIRED WAIVER
Reviewed b]r. C) Date:
Critical Areas Checklist.doc/3.19.2001
City of Edmonds
Critical Areas Determination
Applicant: Dan Tomasek for Fred A. Determination #: CA-01-79
Wolgomatt (Owner)
Project Name: I Permit Number: I
Site Location: Lot directly west of 503 9 th Property Tax Acet #: 2470 322 060 00
Ave. N.
Project Description:
Non -Project Specific
Determination: Study Required:
During review and inspection of the subject site, it was found that the site appears to contain a
critical area, including a Steep Slope Hazard Area pursuant to Chapter 20.15B of the Edmonds
Community Development Code (ECDC).
Based on this finding, prior to submission of any development permit, you will be required
satisfy the requirements of ECDC 20.15B by completing a Critical Areas Study consisting of the
following:
Steep Slope Hazard Area Delineation ReQuirements:
To deten-nine if a Steep Slope Hazard Area does exist, a topographic survey prepared by a
Licensed Land Surveyor delineating Steep Slope Hazard Areas must be completed. Any slope of
40% or more with at least 20 feet of rise will be classified as a Steep Slope Hazard Area. A 50-
foot buffer is required from both the top and toe of the slope. A 15-foot building setback is
required from the 50-foot buffer. The top and toe of the slope as well as the buffer and building
setbacks should be clearly identified on the survey.
For development of any kind which is proposed within the critical area, 50-foot buffer or 15-foot
buffer setback, it must be shown that the development will not adversely impact the Critical Area
or its buffer, by doing one or possibly both of the following depending on the outcome of the
study:
For development proposals which will occur within the 50-foot buffer, but no closer than
10 feet from the top or toe of the slope, the 50-foot buffer requirement may be reduced to
10 feet if a study is completed by a licensed geologist or geotechnical engineer which
clearly demonstrates that the proposed buffer alteration will have no adverse impact upon
the site, the public or any private party.
2. If development must occur within the critical area, buffer, and/or buffer setback, and is
not identified as exempt per ECDC Chapter 20.15B, a Reasonable Use Exception and
Variance must be obtained pursuant to ECDC 20.15B. 170A and 20.1513.040C.
If the results of the Critical Areas Study detennine that the lot may not be developed, the
applicant may apply for a Reasonable Use Exception and Variance pursuant to ECDC
20.15B. 170(A) and 20.15B.040(C)).
If the property owner wishes to apply for a specific development permit which they feel
would not impact the Critical Areas located on the site, they may submit their proposal to
the Planning Department for review. If the Planning Department rinds that the proposed
development permit will not adversely impact a Critical Areas or its buffers, a conditional
waiver may be issued on a project by project basis. Please call me at (425) 771-0220 if you
have any questions.
Name
Signature
Date
Cited sections of the Edmonds Community Development Code (ECDC) can be found on the City of Edmonds
website at www.cl.edmonds.wa.us.
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M.S.C.E., M.B.A. Geotechnical /Civil Engineer
&"FREET FILE January 13, 2005
City of Edmonds
cto Eric Thuesen Custom Homes
18333 85h Pl. W
Edmonds, WA 98026 coli
Subject: Geotechnical and Drainage Evaluation — Design Criteria
509 9th Ave. N, Edmonds, Washington
Proposed Two New Residences with Access
This engineering report presents the results of a geotechnical evaluation of the
property at 509 9th Ave. N, Edmonds, Washington. This evaluation was required due to
owner / contractor concerns, as well as City of Edmonds requirements for steep -slope
development.
REFERENCES:
* Site Plan and Topographic Survey by LSA
* Proposed Two New Residence and Driveway Access Plans (furnished by
0 developer) D. Bruce, P.E. dated October 24, 2001
Preliminary Geotechnical Evaluation by
Site photographs
BACKGROUND:
The overall property at 509 91h Ave. N (formerly known as the Wolgamoft '
property) is approximately 110 feet wide (along 9' Ave. N), and approximately 500 feet
deep.
The existing residence at 503 9th Ave. N (the Wolgamoft residence) is to remain.
It is understood that property developer (Eric Thuesen) proposes to construct two
new single-family residences down -slope (westerly) of the existing residence. One new
residence will beconstructed in the area currently occupied by the historic tennis court.
The other residence will be located westerly of the first residence.
It is understood that driveway access will be from the north side of existing
residence and allow access to each of the two new homes (see Project Plans).
SOILS - FOUNDA 7"IONS SITE DEVELOPMENT - INSPECrYOV - DRAINAGE - DESIGN& PERMIT - LEGAL
- - - .... -.^ - 111 --- % - I.-
City of Edmonds
c/o Eric Thuesen Custom Homes
January 13, 2005
Page 2
This engineer evaluated the ' overall property in 2001. Several prospective
developers have looked at the property since that time. I
As stated in the October 24, 2001 preliminary report, the pri�rary geotechnical
feature affecting development are the slopes (see Topographic Ma' for specific slope
P
declinations).
Visual observation during 2001 (as well as the past 3-1/2years) has revealed no
evidence of any geotechnical distress: no slides, no sloughing, nosoil tension cracks, or
any evidence of significant erosional degradation.
This engineer understands that the lower portion of the over'all property (adjacent
8 th Ave. N) has been designated a,wetland zone (see Project Site Plan)
EVALUATION:
In order to augment the existing site geotechnical informatio I n, 2 soil test pits
were dug by backhoe on September 4, 2002. i
Recently, 4 soil test pits were dug by hand in the sloped por�ion of the property
below proposed house No. 2. The recent.test holes were dug to assess the viability of
on -site storm water infiltration. I
The September 4, 2002 test pits were dug in the vicinity of H' ouse No. 1 (tennis
court house) and revealed similar sub -grade conditions, namely:
0" to 6" Lawn, organics, roots, ai
6" to 4' (bottom of pits) Very dense sands with g
No water was encountered in either of these two test pits
remained vertical and stable. No sloughing or caving occurred.
January 2005 test holes on slope.
Five test holes were hand dug to approximately 3-foot d
below proposed House No. 2. The findings of all 5 test holes r
grade conditions, namely:
organic silt
vels
I test pit walls
5 on the slope
led similar sub-
0" to 6" Organics, roots, and fore9t duff
6" to 40" (bottom of holes) Dense sand. Relatively clean with fines
(soil passing No. 200 sie I ve) estimated to be
less than 10 percent
City of Edmonds
c/o Eric Thuesen Custom Homes
January 13, 2005
Page 3
No water was encountered in any of the five test holes. All test hole walls
remained vertical and stable. No sloughing or caving occurred.
NOTE: See later section on drainage for results of infiltration test.
CONCLUSIONS I RECOMMENDATIONS,:
Based on the findings of this investigation, and experience with similar sites in
the area, the property at 509 9th Ave. N, Edmonds, Washington is geotechnically
approved for the proposed 2 new residences, subject to the following:
Standard reinforced continuous and spread footings. Allowable bearing
pressure: 2,000 p.s.f.
0 Equivalent fluid pressure of 35 p.c.f. is recommended for any retaining wall
design provided drainage zone is inspected and verified by this engineer.
'For retaining wall design, use friction factor of 0.55 and passive pressure of 350
p.c.f.
NOTE: It is understood that the driveway access will require a reinforced
concrete retaining wall to provide support for the driveway. It is essential that
the retaining wall foundation be founded on dense native sub -grade soils as
verified by geotechnical inspections.
Geotechnical inspections by this engineer prior to any foundation concrete
placement.
The proposed structures can be supported on conventional continuous and
spread footings bearing on undisturbed native soils or on structural fill placed above
native soils. See the later sub -section entitled General Earthwork and Structural Fill for
structural fill placement and compaction recommendations. Continuous and individual
spread footings should have minimum widths of eighteen (18) and twenty-four (24)
I
inches , respectively, and should be bottomed at least eighteen (18) inches be ow the
lower adjacent finish ground surface.
Depending on the final site grades, some over -excavation may be required below
footings to expose competent native soils. Unless lean concrete is used to fill the over
excavated hole, the width of the over -excavation at the bottom must be at least as wide
as the sum of two times the depth of the over -excavation and the footing width. For
example, an over -excavation extending two feet below the bottom of a three-foot wide
footing must be at least seven feet wide at the base of the excavation.
City of Edmonds
c/o Eric Thuesen Custom Homes
January 13, 2005
Page 4
Footings constructed according to the above recommendations may be designed
for an allowable soil bearing pressure of two thousand (2,000) pounds per square foot
(p.s.f.). A one-third increase in this design bearing pressure may be used when
considering short-term wind or seismic loads. For the above design criteria, it is
anticipated that total post -construction settlement of footings founded on competent,
native soils (or on structural fill up to five (5) feet in thickness) will be about one-half
inch, with differential settlements on the order of one -quarter inch.
Lateral loads due to wind or seismic forces may be resisted by friction between
the foundations and the bearing soils, or by passive earth pressure acting on the
vertical, embedded portions of the foundations. For the latter condition, the foundations
must either be poured directly against undisturbed soil or the backfill placed around the
outside of the foundation must be level structural fill. We recommend the following
design values be used for the foundation's resistance to lateral loading:
ParAmeter Design Value
Coefficient of Friction 0.55
Passive Earth Pressure 350 p.c.f.
Where:
(1) p.c.f. is pounds per cubic foot. uted using the equivalent fluid density.
(2) Passive earth pressure.is comp
We recommend that a safety factor of at least 1.5 be used for design of the
foundation's resistance to lateral loading.
SLABS -ON -GRADE:
Slab -on -grade floors may be supported'on undisturbed, competent native soils or
on structural fill. The slabs may be supported on the existing soils provided ihese soils
can be re -compacted prior to placement of the free -draining sand or gravel underneath
the slab. This sand and gravel layer should be a minimum of four (4) inches thick. We
also recommend using a vapor barrier such as 6-mil. plastic membrane beneath the
slab with minimum overlaps of 12 inches for sealing purposes.
PERMANENT FOUNDATION AND RETAINING WALLS:
Retaining walls backfilled on one side only should be designed to resist lateral
earth pressures imposed by the soils retained by these structures. The following
City of Edmonds
c/o Eric Thuesen Custom Homes
January 13, 2005
Page 5
recommended design parameters are for walls less than twelve (12) feet in height,
which restrain level backfill:
Parameter
Active Earth Pressure*
Passive Earth Pressure
Coefficient of Friction
Soil Unit Weight
Where:
Design Value
35 p.c.f.
350 p.c.f.
0.55
125 p.c.f.
(1) p.c.f. is pounds per cubic foot
(2) Active and passive earth pressures are computed using equivalent fluid
densities.
For restrained walls which cannot defect at least 0.002 times the wall
height, a uniform lateral pressure of one hundred (100 p.s.f. should be
added to the active equivalent fluid pressure).
The values given above are to be used for design of permanent foundation and
retaining walls only. An appropriate safety factor should be applied when designing the
walls. We recommend using a safety factor of at least 1.5 for overturning and sliding.
The above design values do not include the effects of any hydrostatic pressures
behind the walls and assume that no surcharge slopes or loads will be placed above the
walls. If these conditions exist, then those pressures should be added to the above
lateral pressures. Also, if sloping backfill is desired behind the walls, then we will need
to be given the wall dimensions and slope of the backfill in order to provide the
appropriate design earth pressures.
Heavy construction equipment should not be operated behind retaining and
foundation walls within a distance equal to the height of the wall, unless the walls are
designed for the additional lateral pressures resulting from the equipment. Placement
and compaction of retaining wall backfill should be accomplished with hand -operated
equipment.
Retaining Wall Backfill
Backfill placed within eighteen (18) inches of any retaining -or foundation walls
should be free -draining structural fill containing no organics. This backfill should contain
no more than five (5) percent silt or clay particles and have no particles grpater than
City of Edmonds
c/o Eric Thuesen Custom Homes
January 13, 2005
Page 6
four (4) inches in diameter. The percentage of particles passing the No. 4 sieve should
be between twenty-five (25) and seventy (70) percent. Due to their high silt content, if
the native soils are used as backfill, a drainage composite, such as Mirafi and
Enkadrain, should be placed against the retaining walls. The drainage composites
should be hydraulically connected to the foundation drain system. The purpose of these
backfill requirements is to assure that the design criteria for the retaining wall is not
exceeded because of a build-up of hydrostatic pressure behind the wall. The
subsection entitled Gene ructural- Fill contains recommendations
regarding placement and compaction of structural fill behind retaining and foundation
walls.
EXCAVATION AND SLOPES:
In no case should excavation slopes be greater than the limits specified in local,
state and national government safety regulations. Temporary cuts up to a heig. ht of
four (4) feet deep in unsaturated soils may be vertical. For temporary cuts having a
height gr I eater than four (4) feet, the cut should have an inclination no steeper than 1: 1
(Horizontal:Vertical) from the top of the slope to the bottom of the excavation. Under
specific recommendations by the geotechnical engineer, excavation cuts may be
modified for site conditions. All permanent cuts into native soils should be inclined no
steeper than 2:1 (H:V). Fill slopes should not exceed 2HAV. it is important to note that
sands do cave suddenly, and without warning. The contractors should be made aware
of this potential hazard.
Water should not be allowed to flow uncontrolled over the top of any temporary
or permanent slope. All permanently exposed slopes should be seeded with an
appropriate species of vegetation to reduce erosion and improve stability of the surficial
layer of soil.
DRAINAGE CONSIDERATIONS:
Footing drains are recommended at the base of all footings and retaining walls.
These drains should be surrounded by at least six (6) inches of one -inch -minus washed
rock wrapped in non -woven geotextile filter fabric (Mirafi 140N, Supac 4NP, or similar
material). At the highest point, the perforated pipe invert should be at least as low as
the bottom of the footing and it should be sloped for drainage. Ali roof and surface
water drains must be kept separate from the foundation drain system.
No groundwater was observed in the September 2002 test pits or the January
2005 test holes. Seepaqe into the planned excavation is possible, and likely if
excavation occurs during winter months, and if encd,untered should be drained away
, French drains, or Oy.ppmping
from the site by use of drainage ditches, perforated pipe
City of Edmonds
c/o Eric Thuesen Custom Homes
January 13, 2005
Page 7
from sumps interconnected by shallow connector trenches at the bottom of the
excavation.
The excavation of the site should be graded so that surface water is directed off
the site and away from the tops of slopes. Water should not be allowed to stand in any
area where foundations, slabs, or pavements are to be constructed. Any exposed
slopes to be covered with plastic to minimize erosion. Final site grading in areas
adjacent to buildings should be sloped at least two (2) percent away from the building,
except where the area adjacent to the building is paved.
GENERAL EARTHWORK AND STRUCTURAL FILL:
The proposed building and pavement areas should be stripped and cleared of all
surface vegetation, all organic matter, and other deleterious material. The stripped or
removed materials should not be mixed with any materials to be used as structural fill.
Structural fill is defined as any fill placed under the building, behind permanent
retaining or foundation walls, or in other areas where the underlying soils needs to
support loads. This engineer should observe site conditions during and after excavation
prior to placement of any structural fill.
All structural fill should be placed in horizontal lifts with a moisture content at or
near the optimum moisture content. The optimum moisture content is that moisture
content which results in the greatest compacted dry density. The moisture content of fill
soils is very important and must be closely controlled during the filling and compaction
process.
The allowable thickness of the fill lift will depend on the material type, compaction
equipment, and the number of passes made to compact the lift. In no case should the
lifts exceed twelve (12) inches in loose thickness. The following table presents
recommended relative compaction for structural fill:
Location of Fill Placement
Beneath footings, slabs or walkways
Behind retaining walls
Beneath pavements
Minimum Relative
Compaction
95%
90%
95% for upper 12 inches of
Sub -grade, 90% below that level
City of Edmonds
c/o Eric Thuesen Custom Homes
January 13, 2005
Page 8
Where: Minimum relative compaction is the ratio, expressed in percentages, of
the compacted dry density to the maximum dry density, as determined in
accordance with ASTM Test Designation D-1 557-78 (Modified Proctor).
Use of on -Site Soils
if grading activities take place during wet weather, or when the sandy, on -site
soils are very wet, site preparation costs may be higher because of delays due to rains
and the potential need to import granular fill. The on -site soils are generally sandy and
thus are not highly moisture sensitive. Grading operations will be difficult when the
moisture content of these soils greatly exceeds the optimum moisture content.
Moisture sensitive soils will also be susceptible to excessive softening and
t6pumping" from construction equipment traffic when the moisture co I ntent is greater than
the optimum moisture content.
Ideally, structural fill, which is to be placed in wet weather, should consist of a
granular soil having no more than five (5) percent silt or clay particles. The percentage
of particles passing the No. 200 sieve should be measured from that portion I of the soil
passing the three -quarter -inch sieve.
The use of "some" on -site soils for fill material may be acceptable if the upper
organic materials are segregated and moisture contents are monitored by engineering
inspection.
DRAINAGE CONTROLS:
No drainage problems were evident with the existing residence and the overall
site. Surface runoff would flow westerly following the topographic slope. However, the
extremely porous sub_grade sands allow for infiltration.
This engineer performed an on -site infiltration test (complying with King County
Surface Water Drainage Manual standard methodology). The 5 hand dug test holes
were filled with water during saturated winter conditions. All 5 test holes drained very
quickly at maximum infiltration rates.
This maximum infiltration (greater than 24 inches in 20 minutes) is expected due
to the presence relatively clean sands.
Design Infiltration Rate: 15 inches per hour
City of Edmonds
c/o Eric Thuesen Custom Homes
January 13, 2005
Page 9
This engineer recommends using 15 inches per hour as a design infiltration rate
in conjunction with storm water control for the two proposed houses.
Use standard infiltration trench designs attached.
Geotechnical inspections required during installation of infiltration trenches.
CONCRETE:
All foundation concrete (footings, stem walls, slabs, any retaining walls, etc.)
shall have a minimum cement content of 5-1/2 sacks per cubic yard of concrete mix.
DRIVEWAY ZONE — RETAINING WALL:
As stated, the driveway access will require a reinforced concrete wall and
subsequent fill material. It is essential that base of driveway retaining wall be founded
in dense, native sub -grade soils as verified by geotechnical inspections. Additionally,
proper placement of approved fill material requires inspections.
SLOPES — SETBACKS / BUFFERS:
There are no geotechnical conditions limiting or restricting the location of the two
new residences.
The area proposed for infiltration is stable and will accommodate infiltration
trenches designed in accordance with the criteria herein.
EDMONDS STEEP SLOPE EXEMPTION:
The following items respond to City of Edmonds steep slope exemption criteria.
'o The site will be stable following the permitted activity provided geotechnical
inspections verify the recommendations in this report.
The proposed development will occur on steep slope areas that qualify as
advance outwash in accordance with the geological map of the Edmonds east
and part of the Edmonds west quadrangles by James P. Minnard.
* Fill material: Neither of the proposed 2 new residences will require fill.
City of Edmonds
c/o Eric Thuesen Custom Homes
January 13, 2005
Page 10
The access driveway will require a reinforced concrete retaining wall and
approved structural fill. It is understood that this engineer will perform on -site
geotechnical inspections to verify proper placement of approved fill materials.
• None of the following conditions exist on the steep slope area: impermeable soils
inter -bedded with granular soils, springs or groundwater seepage, significant
visible evidence of groundwater seepage, previous land sliding or instability, or
existing land slide deposits.
• The thickness of organics, debris, weathered soils, coiluvial soils or soils
exhibiting loose conditions on or adjacent to the steep slope are less than 3 feet.
• All excavations on the steep slopes will not extend below a 35 degree plane
extended down from the property line.
* All retaining structures on steep slopes shall be engineered structures
conforming to the State Building Code, and subject to on -site geotechnical
inspections by this engineer. No rockeries greater than 4 feet in height are
proposed.
* An undisturbed buffer of 15 feet shall be maintained from the proposed
development to adjacent residential properties.
* The proposed development (2 new residences and access driveway) will not
decrease the stability of any adjacent property, subject to on -site geotechnical
inspections by this engineer.
INSPECTIONS:
The recommendations of this report are only valid when key geotechnical
aspects are inspected by this engineer during construction:
• Soil cuts
• Foundation sub -grade verification
• Retaining wall, or rockery placement
• Any fill placement
• Subsurface drainage installation
• Infiltration trench placement
• Temporary and final erosion control
City of Edmonds
c/o Eric Thuesen Custom Homes
January 13, 2005
Page 11
SUMMARY:
The proposed 2 new residences and access driveway at 506 9th Ave. N,
Edmonds, Washington are geotechnically viable when constructed in accordance with
the recommendations herein, compliance with City of Edmonds approved plans and
requirements, and key geotechnical inspections during construction'.
GEOTECHNICAL REVIEW OF FINAL PLANS:
At the time of this investigation and report, final house plans were not available
for review. I
As stated in this report, Eric'Thuesen proposes to construct �2 new residences in
accordance with the Site Plan with a north side access driveway. The dense native
sands allow for standard foundation construction in accordance wifh the
recommendations of this report. ' I
Additionally, the native sands allow for storm water infiltrati69 west of the second
house, subject to inspections. I
Prior to final permit issuance, this engineer should review the final house plans to
verify compliance with the recommendations of this report.
Upon satisfactory review, 4 "Statement Of Minimal Risk" wil ! I be issued.
CLOSURE:
The findings and recommendations of this report were prepared in accordance
with generally accepted professional engineering principles and pr i actice. No other
warranty, either express or implied, is made. The conclusions arel based on the results
of the field exploration and interpolation of subsurface conditions between explored
locations. If conditions are encountered during construction that appear to be different
+11; r% innar chn"Id be notified to observe the
than those descriDed in MIS 1UPU1 ' L, 0 U �J
situation and review and verify or modify the recommendations.
If there are any questions, do not hesitate to call.
Dennis M. Bruce, P.E. 11
Geotechnical / Civil Engillluul
DMB:abj
Feb 02 05 10:50a D. Bruce, P.E. 20G-54G-8442 P.1
Dennis M. Bruce, RE. �-Am 13 f �LOOK-
M.S.C.E., M.B.A. Geotechnical /Civil Engineer
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Feb 02 05 10:50a D. Bruce, P.E. 206-546-8442 P.2
City of Edmonds
c/o, Eric Thuesen Custom Homes
January 13, 2005
Page 8
Where: Minimum relative compaction is the ratio, expressed in percentages, of
the compacted dry density to the maximum dry density, as determined in
accordance with ASTM Test Designation D-1 557-78 (Modified Proctor).
Use of On -Site Soils
if grading activities take place during wet weather, or when the sandy, on -site
soils are very wet, site preparation costs may be higher because of delays due, to rains
and the potential need:tb import granular fill. The on -site soils are generally s�ndy and
thus are not highly moisture sensitive. Grading operations.will be difficult when the
moisture content of th�ese soils greatly exceeds thja optimum moisture content.
moisture- sensitive soils will also be-s-usceptible to excessive softenin.% and
oisture cohtent isg'reater than
,.pumping" from construction equipment tFaffic wh6ri the M'
the optimum moisture content.
Ideally, structural fill, which is to be placed in wet weather, should consist of a
granular soil having no more than five (5) percent silt or clay particles. The percentage
of particles passing the No. 200 sieve should be measured from that portion of the soil
passing the three -quarter -inch sieve.
The use of "some" on -site soils for fill material may be acceptable if the upper
organic materials are segregated and moisture contents are monitored by engineering
inspection.
DRAINAGE 1,ONTROLS:
No drainage problems were evident with the existing residence and the overall
site. Surface runoff would flow westerly following the topographic slope. However, the
extremely porous sub -grade sands allow for infiltration.
ing County
This engineer performed an on -site infiltration test (complying with K
Surface Water Drainage Manual standard methodology). The 5 hand dug test holes
el were filled with water during saturated winter conditions. All 5 test holes drained very
quickly at maximum infiltration rates.
This maximum infiltration (greater than 24 inches in 20 minutes) is expcted due
to the presence relatively clean sands.
Design Infiltration Rate: 15 inches per hour
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JS 09: 14a D. Bruce, P. E. 206-546-0442 p.3
C.2.3-114MIRATION *OES AND DRYWELLS
FIGURE C-2-B TYPICAL DOWNSPOUT ]NFMTRATION SYSTEM
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Date: cowrouR5 2'iw-rF-vAL,5
amec/-'hwt�r b UVVNER/CONTRA-'TOR iS RESPONSIBLE
FOR EROSION 00Ni KOL AND DAMAGE
May 15 04 019:31a D. Bruce, P.E. 20G-546-8442 P�l
Dennis M. Bruce, P.E.
M.S.C.E., M., A. Geotechnical /Civil Engineer
November 12, 2004
City of Edmonds
clo Eric Thuesen Custom Home
I 8M Wh PL W.
Edmonds, WA 98026 16-
S I
Subject: Geotechnical Review — Site Plan
Proposed Now Residence So 99h Ave. North
Edmonds, Washington
This engineering report presents d'ie results of a geotechnical review of the
property and site plan fbr the proposed rw-w residence by Thuesen Custom
Homes.
REFERENCES:
• Preliminary* geotechnical report by D. Bruce, P. E. October 21, 2001
• Soil test pit photographs dated September 4, 2002
• Site Plan for proposed for new residence by Thuesen homes -
BACKGROUND:
This engineer has provided geotechnical services for potential buyers and
developers of the overall property at 503 e Ave. N.
The soil test pits where dug on September 4, 2002 in the vicinity of the
proposed new home by Thuesen Custom Homes.
This engineer venfled very dense native sands with gravels at shallow
footing depths.
PROPOSED NEW RESIDENCE:
This engineer has reviewed the attached sit plan by Thuesen Custom
Homes for the new residence to be located inthe "Tenriis court" zone.
The topography for the site has been performed by LSA and defines the
top -of -slope. See survey map.
SOILS - FOUVIRAnaVS - V1M,0-CvEjOqVEW . INSpECTIOW . DR&,VA6,- '0'FS1G1Vj'0Efl
'WIT - f-154GAL
P.O. Box 55502 - Shoreline, WA 98155 - (206) 546-9217 & FAX (206) 546-8442
FILE
u-tuti : &-ia
D. Bruce, P.E.
p. 2
Ciby of Edmonds
11-9-04
Page 2 of 2
206-546-6442
0
The proposed site plan for the new residence vWll result in the foundation
to be set back 25 feet from the top -of -steep slope boundary.
The reduction of the buffer from 50 feet to 25 feet will have no adverse impact on
the site, the public, or any private party, subliect to nsite geotechnical
inspections by this engineer.
SUMMARY:
The proposed new residence and location per site plan (with 25 foot set
back from top of slope ) is geotechnically w1w—oved subject to onsite
inspections by this engineer.
If there are any questions, do not hesitate to call.
XL"RZI, / PC.
Dennis M. Bruce, P.E.
Geotechnical / Civil Engineer
DMB:lmb
SIMA
M
Peter Chopelas, PE
Engineering & Design Services
307 N. Olympic Ave, Suite 208
Arlington, WA 98223
Chopelasandassociates@glnail.com
Geotechnical Addendum
To the report Dated March 23, 2012, as Revised in May 15, 20'12, and October 25, 2012
October 17'h, 2013
Eric Thuesen
509-96' Avenue N.
Edmonds WA 98020
Ericthuesen(@froritier.com 1-425-772-9401
_01
OCT 3 12013
DEVELOPMENT SERVICES
. COUNTER
Subject: geotechnical review of proposed site plan changes for plan ck # 2013-1175 at the above
address.
Site plan changes: This addendum should be included with the Geotech report for this property
dated march, 23, 2012, as revised May 15'h and Oct 25, 2012.
A review of the proposed site plan changes and the original geotechnical report was
accomplished. All of the changes are acceptable with the following conditions since none of the
proposed changes affect any of the original recommendations, and none of the changes will have
any significant impacts to the critical slope.
. There is a proposed short 2 to 3 ft tall concrete wall to go along the south property line
down the slope of about 30 percent, the wall turns 90 degrees from the south property line to join
the cabana. A fence no taller.than 6 ft (total height) is proposed on top of this wall and footing.
This wall and fence can be installed as proposed as long as it rests on original undisturbed sub
soil below any old fill or topsoil and roots (or other organic material). The bottom of the footing
should be min. of 12" below final grade to protect against frost heave. This area is mostly
undisturbed glacial till, very dense and very stable, therefore it will not affect slope stability.
A four foc�t total height retaining wall is proposed at about 24-25 from the house, back
from the top of original slope to separate the upper and lower back yard- areas. The footing for
this must bear on original undisturbed subsoil below any old fill or organic material (top soil,
roots, etc). This wall will also incorporate a raised planter for landscaping purposes. This
retaining wall and planter is acceptable as proposed since it will not be built on the slope and
should bear on original undisturbed soil.
Another proposed change is the addition of an in -ground hot tub that will be adjacent to
the existing home about 20 ft back from the top of the old slope. The soil in this area was
examined and it is original undisturbed glacial till, it is very dense and has a very high bearing
capacity. There are no restrictions to installing this hot tub at this location. It will not affect the
slope stability.and is back from the critical slope area.
If you have any questions or if j,!1pgk be of further assistance please feel free to call or
0
email at the above address.
Peter Chopelas PE.
Peter Chopelas, PE
Engineering & Design Services
307 N. Olympic Ave, Suite 208 r
T 3
Arlington, WA 98223 T �.:-"'ET FILE
(360) 653-4615; Chopelasandassociates@gmaii.com
September 16, 2013 RECEIVED
Eric-Thuesen OCT 2 2 2013
509 9th Avenue N.
Edmonds WA 98020 DEVELOPMENT SERVICES
EnCtIlUeseW&,frontier.com COUNTER
1-425-772-9401
Subject: 4 foot retaining wall for Thuesen Custom homes. Ref BLD 20110775
A four foot tall retaining wall is designed for landscaping in the rear yard, for use at the above
address. The following design conditions were used:
ateral soil loads and vertical loads were analyzed for the subject retaining wall according to
-,-Ye requirements of the 2009 International Building Code (ASCE 7-05). The following design
conditions for the analysis are based on the site conditions or according to the minimum code
requirements-.
3oil Bearina Capacity:
2,000 PSF
e i lent fluid pressure:
au'va
35 PSF
iv
.1in. concrete strength:
2500 PSI
'Y,-"n. steel reinforcement:
grade 40 (40,000 psi)
:--� smic Site Class:
D
-ic se smic tbrces. Overturning
;,,e safety factor and equivalent fluid pressure accommodates tt I
Fir-6 lateral slidinR fbrces exceed the required safety factor of 1.5. Concrete strength and steel
r-.inforcemcnt is in excess of the applied loads, and meet min. reinforcement requirements I*or
-emforced concrete and temperature related steel reinforcement. Calculations are included.
Tf, vou have any questions or are in need of further assistance please feel free to call.
Peter Chopelas, PE RECEIVED
EngineeC7in,51 & Design Se7-Vices
-307 N. Olympic Ave, Suite 208 CT 2 2 2013
-A
rlington, WA 9822-3
(360) 65-3-4615 Chopelasandassor-iates@gmail.com DEVELOPMENT SERVICES
COUNTER
Tv� 'ic sev\ fp, I A Y� 6 f, tz�,- - I-
A
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7,e,'-
_7
7
pj
mbn. I
RECEIVE
f
OCT 2 2 2013
DEVELOPMENT SEM
. COUNTER
73
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571
CITY OF EDM-ON6--§—'--
BUILDING DEPARTMENT
W 0 R K Re-121
ADDRESS
OWNER
APPROVED DATE:
BLDG. OFFICIAL
PERMIT NUMBER
OeO ZO /9 - // 7-57
OCT 2 2 2013
DEVELOPMENT SERVICES
COUNTER
APeter Chopelas, PE
Engineering & Design Services RECEIVED
M7 N. Olympic Ave, Suite 208
Arlington, WA 98223 OCT 2 2 2013
(360) 653-4615; Chopelasandassociates@gmai*l.com
OEVELOPMENT SEWICES
Ge6technical Report
March 23, 2012
Revised: May 15, 2012
Eric Thuesen
509-9'h Avenue N.
Edmonds WA 98020
Ericthuesen(krontier.corn
1-425-772-9401
Subject: geotechnical investigation for plan ck # 2011-0775 accessory structure (cabana) at the
above address
A geotechnical investigation of the above property was performed to address slope stability,
erosion control and drainage issues. This sloping sitd-has been extensively altered due to
previous construction activities including extensive cut and fill of the slope. A small accessory
structure (cabana) and a retaining wall is proposed to be built below the residence at the top of
slope below the home. The investigation consisted of a site inspection to examine soil's and site
conditions and to take measurements on the sites. A review of published material on local
geology from the USDA Soil Survey of Snohomish County, and a review of the geotechnical
report done by Dennis Bruce PE, dated Jan 13th, 2005 for this site.
I
The investigation found that the site can be made satisfactory with deep foundations for the
proposed accessory building, and a retaining wall with footings deep enough to get below the fill,
and the use of surface stabilization measures. The building site for the cabana is on shallow old
fill placed at the top of the slope to make the �ack yard terrace larger. There is an existing site
drainage system, including yard drains, and a conveyance system that transports all roof and
driveway run-off to the base of the hill. The fill, though stable for landscaping features, is not
suitable for permanent buildings. Therefore the proposed building and retaining wall should be
built on foundations deep enough to bare on the original undisturbed subsoil. This will allow the
proposed development with a generous safety factor of 1.5 or greater. -
These measures will reduce risk of landslides, increase slope -sfability and will. not increase .
surface water discharge, sedimentation or erosion on downstream sites. This development will
not increase surface water discharge, and it will not decrease slope stability but rather increase
stability and it will not adversely impac A i.a.1 areas.
ZIA- GO
FIESUB
W,
14AY 2 9 2012
co
13U[LDING DEPAK."MEN1
Peter Chopelas PE
�7 4 CITY OF EDMONDS
Project Description
The building site is a residential building lot of approximately 0.2 acres served by a municipal r,
sewer and a public water supply, and with an existing residence and garage built on a terrace on a
sloping site. There is a proposed accessory building of 320 SF, with a 360 SF attached deck, a
retaining wall and back fill to enlarge the useful backyard, placed at the top of a steep slope
below the existing residence. The building site is about 160 feet from the toe of the slope, and
about 50 feet in elevation above it. The foundation will be deep enough to reach below the old
fill to bear on original undisturbed soil. These are Allowed Activities in a critical area per
23.80-090. B (1).
23.40.120 Mitigation sequencing.
1. The impact cannot be avoided since it is the property owner's desire to increase the
safety factor of the slope and enlarge the useful yard area by adding an engineered
retaining wall and building the cabana with an engineered foundation on the edge of a
small level terrace.
2. The impacts are minimized by building a modest building and enlarging the useful area
of the backyard byabout 300 SF. Site disturbances on the slope should be kept to a
minimum during construction, it should be done during the dry season, and all exposed
soil will be covered during the construction phase. Both temporary and permanent soil
stabilizing measures are recommended.
3. There are no impacts to wetland nor to any habitat area since none are disturbed. The
site will be more stable and surface vegetation restored after the project is completed.
4. Both the foundation and retaining structure are engineered structures and will result in
a safer, more stable slope condition than the existing site conditions.
5. The recommendations for the proposed project will result in long term slope stability.
Recommendations include installing stabilizing engineered structures, protecting and
maintaining the vegetation on the slope, and to minimize unnecessary site disturbances.
6. No compensation for impact to wetlands, frequently flooded areas, and fish and
wildlife habitat conservation areas are required since none are disturbed.
7. Monitoring the hazard will be done during. the construction since the soil conditions
have to be inspected prior to placing the footings, and during the construction to verify
design conditions are met. Design adjustments may be made tonuinimize any hazards.
Site Conditions
The terrain slopes steeply to the west at about 32 percent average grade from a near level terrace
on the east half where the existing residence is located. The terrace has existing lawn and
landscaping and there is mix of grasses and landscaping shrubs and small to medium trees on the
slope. There is no significant surface drainage on the site, and no seepage on the site. There is
an existing drainage and conveyance system to transport surface discharge from the roof tops and
driveway to the base of the slope to the west. The proposed construction site is at about 50
percent grade, which was probably created by placement of fill on the slope from the spoils of
the foundation excAtions when the house was built since deePIP, was found near the top of the
slope.
Local Geology
The subject site lies along a slope forming the edge of the highland plateau of the Edmonds area.
The general stratigraphy (soil layering) of the area is characterized -by fluvial. and glacio-fluvial-
sediments from sea level to around 200 feet, with glacial till and sand deposit plains that make up
the surficial sediments on most of the plateau. The USDA Soil Survey of Snohomish County
maps the soil as Everett gravelly sandy loam and Alderwood gravelly sandy loam. The Everett
soil is deep excessively drained soil on terraces and outwash plains. It is formed in glacial out
wash. The sub -soil is dark brown gravelly sandy loam down to about 60 inches, with increasing
gravel at the deeper depths. The Alderwood gravelly sandy loam is moderately well drained soil
on till plans, moderately deep over a hardpan, and formed in glacial till. Both of these soils are
very stable and suitable for building site development.
This soil has good strength and is not prone to slumps or landslides. It is subject to surface
erosion when exposed to the weather and measures are required to prevent erosion. This soil is
not prone to liquefaction.
The site shows no evidence of landslides or deep soil instability. There were some minor tension
cracks in the soil near the top of the slope, but this was old fill that has been settling and causing
surface irregularities. This does not pose a hazard to this site or the adjoining site, and the slope
will be reinforced with the addition of the proposed structures.
There is no flooding risk on this property. There are no wetlands or surface water on this
property, however several hundred feet down slope there is a wetland at the toe of the slope.
Geotechnics
Surface soils have been inspected over most of the site and on the slopes by visual inspections'.
The underlying undisturbed soil on the subject site is deep silty sand, this is old alluvial outwash.
The soil on the. proposed building site below the existing home is undifferentiated fill I to 4 feet
deep, likely the spoils from the house site excavations. It is a mix of sand and gravel and has
organic material and other debris mixed into it. This was placed at the top of the slope, over
steepening the upper 10 feet or so of the slope.
lo I
Soil Mo, 7
Soil log 3
Soil log 4
PSoil
0-12" mixed fill
0-36" mixed fill
0-48"+ mixed fill
0-18" fill
12"+sand loarnEP36"+
sandy loam
18"+ sandy loam
0 .
0011 jog table
Slope stability: Analysis of the natural grade of the steeper parts of the site using the Singh
diagrams indicates that the slope shows a Factor of Safety of 1.8. This reduces to about 1.6 for
dynamic seismic conditions. This indicates a stable slope with a large safety factor over the 1.5
and 1.2 minimum requirements respectively. The upper filled slope is also currently stable, but
with a lower safety factor of about 1.2. This is acceptable for landscaping features, but deeper
footings must be used to get into the underlying original'subsoil. The soil properties of the
undisturbed Everett soil is as follows: density (gamma)= 130 PCF; Cohesion (C)= 100 PSF,
height of the slope is 50 feet.
Erosion: All of the existing site is well protected from erosion with established vegetation All
of the slopes ov ' er 30 percent on this site is subject to severe erosion if the soil is exposed.
Minimize disturbing any vegetation on the slope. Any exposed soil on the site must have deep
rooting ground cover installed as soon as practical, avoid concentrated surface flows on the
slopes, and to transport by tight -line roof and driveway runoff to the base of the slope through the
existing drainage system.
23.90.060 and 23.80.070 Development standards.
The recommendations in the following section will achieve the following:
I - It will not increase the threat of the geological hazard to adjacent properties beyond
predevelopment conditions; and will reduce them since it will improve the safety factor.
2. It will not adversely impact other any other critical areas.
3. These recommendations 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. All are certified as safe as designed, and under anticipated conditions, by a qualified engineer
licensed in the state of Washington.
Note that construction buffers for the proposed development is zero. The proposed changes will
stabilize the slope to bring the safety factor well above the 1.5 minimum, so no buffers are
required for this project. Therefore section 23.80.070 (1) does not apply. However, it is
recommended to keep heavy construction equipment back from the top of the slope at least 10
feet during construction.
This proposed development is certified to:
a. Reduce, and not increase surface water discharge or sedimentation to adjacent properties
beyond.predevelopment conditions;
b. It will increase, and not decrease slope stability on adjacent properties; and
c. These alterations will not adversely impact other critical areas;
3. Design Standards. Development within an erosion or landslide hazard area and/or buffer shall
be designed to meet the following:
a. The proposed development has a design safty factor of 1.5 or above static, and 1.2 and above
dynamic, after the recommendations are accomplished. There is no reduction in the safety factor
for the site, or to any adjacent properties.
b. The Structures and improvements are placed to to avoid geologically hazar . dous areas and to
improve the slope safety factors, and will have no affect on other critical areas;
c. The proposed structures and improvements minimize alterations to the natural contour of the
slope, and foundations are tiered where possible to conform to existing topography;
d. Structures and improvements are located to preserve the most critical portion of the site and its
natural landforms and vegetation;
e. The proposed development do not result in greater ri�k or a need for increased buffers on
neighboring properties;
f. Retaining walls are used to allow the maintenance of existing natural slope rather than graded
artificial slopes;
g. The development minimizes impervious lot coverage, the proposed building is modest in size;
4. Vegetation Retention. All vegetation on the slopes shall be left undisturbed outside of the
construction area;
5. Seasonal Restriction. Clearing shall be allowed only from May I st to October I st 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;
6. Point Discharges. Point discharges from surface water facilities and roof drains onto or
upstream from erosion or landslide hazard area are prohibited. All roof and surface
discharge shall be collected and tight -lined to the existing site drainage system where it is
conveyed to a an approved discharge point where there is no erosion hazaxd.
7. Prohibited Development. No On -site sewage disposal systems are proposed for the site.
Recommendations
The proposed building location can be used with a reasonable assurance of long term slope
stability and safety to the building if the following recommendations are followed:
1 . Conventional footings may be used as long at it is placed a minimum of 12" into the original
undisturbed sub -soil below the old fill. Bearing capacity is 2000 PSF. Equivalent fluid
pressure of 35 PCF for retaining walls for drained on -site back fill. Coefficient of friction
for the soil is 0.55 and passive soil (lateral bearing) pressure of 350 PCF. All bearing soil
should be inspected by the engineer before concrete is poured.
2. The up hill footings of the accessory structure can be supported on two 24" square x 10"
thick concrete footings, one near each comer of the building. These should be placed below
the fill 12" into original undisturbed subsoil. The footings should be reinforced with (3) #4
rebars in each directions (3" clearance from soil). A 12" diameter Sonotiibe formed concrete
column can be installed on top of these footings up to grade, this should be reinforced with
(4) vertical #4 bars with a #3 horizontal hoops every 8". The excavated soil must be back
filled and compacted over and around these footings up to grade.
3. Roof run' --off should be directed to a catch basin in the existing conveyance system and tight -
lined to the base of the slope. No drains or concentrated flows should discharge over the
ground or on the slope.
4. A silt fence should be placed on the downhill side of the construction site to attenuate silt -
laden run-off if necessary. Silt fences should be placed around catch basin inlets. Soil that is'
to be removed and reused around the site should be kept away from the top of the slope.
Soils not to be reused. on the site should be hauled off site to an approved location.
5. The vegetation on the steep slopes should be replaced as soon as practical after construction.
Any disturbed soil in the area of the slope shoiild be protected with jute matte or straw and
replanted with native vegetation. After final grading any disturbed or exposed soil needs to
have topsoil spread and compacted and planted witli'vegetation that will retard erosion and
stabilize the upper soil layers.
Grass seed mixture based on soil type, used for erosion control, should be as follows:
Common Name Percent by Wei2ht
Perennial ryegrass 40
Annual ryegrass 20
Red Fescue 40
This should be applied at a hydro -seed rate of I LB per 1000 sq. ft. (or 60 LB. per acre); or a
hand seed rate for 2 LB. per 1000 sq. ft. (or 87 LB. per acre). Fertilizer shall be 10-20-20,
applied at the rare of 10 LB. per 1,000 sq. ft. (or 400 LB. per acre).
The following native vegetation are acceptable for permanent plantings on disturbed slopes
and buffers:
Trees*( 3-41 size; plant 6' o.c.)
Shrubs*(to be 1-3' size; plant 2 foot
O.C.)
Vine Maple
Kinnick-kinnick
Big leaf maple
Salal
Nobles fir
Snowberry
Grand fir
Vinca Minor
Oregon Grape
Red current
Other native species as recommended by qualified landscape professional knowledgeable in soil
stabilization may also be used.
cri
�o
p--q
0
L)
4
0
-0
0
0
ti
cl,
tb
0
E�
. : t�,
APeter Chopelas, PE
Engineering & Design Services RECEIVED
M N. Olympic Ave, Suite 208 OCT 2 2 2013
Arlington, WA 98223
(360) 653-4615; Chcipelasandassociates@gmail.com DEVELOPMENT SERVICES
COUNTER
Geo'technical Report
March 23, 2012
Revised: May 15, 2012
Eric Thuesen
509-9th Avenue N.
Edmonds WA 98020
Ericthuesene,frontier.com
1-425-772-9401
XZ=
Subject: geotechnical investigation for plan ck # 2011-0775 accessory structure (cabana) at the
above address
A geotechnical investigation of the above property was performed to address slope stability,
erosion control and drainage issues. This sloping sit6has been extensively altered due to
previous construction activities including extensive cutand fi-11 of the slope. A small accessory
structure (cabana) and a retaining wall is proposed to be built below the residence at the top of
slope below the home. The investigation consisted of a site inspection to examine soil s* and site
conditions and to take measurements on the sites. A review of published material on local
geology from the USDA Soil Survey of Snohomish County, and a review of the geotechnical
report done by Dennis Bruce PE, dated Jan 13th, 2005 for this site.
I
The investigation found that the site can be made satisfactory with deep foundations for the
proposed accessory building, and a retaining wall with footings deep enough to get below the fill,
and the use of surface stabilization measures. The building site for the cabana is on shallow old
fill placed at the top of the slope to make the -back yard terrace larger. There is an existing site
drainage system, including yard drains, and a conveyance system that transports all roof and
driveway run-off to the base of the hill. The fill, though stable for landscaping features, is not
suitable for permanent buildings. Therefore the proposed building and retaining wall should be
built on foundations deep enough to bare on the original undisturbed subsoil. This will allow the
proposed development with a gen e'rous safety factor of 1. 5 or greater.
These measures will reduce risk of landslides, increase slope - stability and will not increase
surface water discharge, sedimentation or erosion on downstream sites. This development will
not increase surface water discharge, and it will not decrease slope stability but rather increase
stability and it will not adversely impac"thpr, rit Q
,,,c,,,Lal areas.
Peter Chopelas PE
974
1`1 E S 1 11 ii%
ri U=
MAY 2 9 2012
UILDING DEPAR;.&I
r.17Y OF EDMO DS
40.
Project Description
The building site is a residential building lot of approximately 0.2 acres served by a municipal ,
sewer and a public water supply, and with an existing residence and garage built on a terrace on a
sloping site. There is a proposed accessory building of 320 SF, with a 360 SF attached deck, a
retaining wall and back fill to enlarge the useful backyard, placed at the top of a steep slope
below the existing residence. The building site, is about 160 feet from the toe of the slope, and
about 50 feet in elevation above it. The foundation will be deep enough to reach below the old
fill to bear on original undisturbed soil. These are Allowed Activities in a critical area per
23.80.090. B (1).
23.40.120 Mitigation sequencing.
1. The impact cannot be avoided since it is the property owner's desire to increase the
safety factor of the slope and enlarge the useful yard area by adding an engineered
retaining wall and building the cabana with an engineered foundation on the edge of a
small level terrace.
2. The impacts are minimized by building a modest building and enlarging the useful area
of the back yard by about 300 SF. Site disturbances on the slope should be kept to a
minimum during construction, it should be done during the dry season, and all exposed
soil will be covered during the construction phase. Both temporary and permanent soil
stabilizing measures are recommended.
3. There are no impacts to wetland nor to any habitat area since none are disturbed. The
site will be more stable and surface vegetation restored after the project is completed.
4. Both the foundation and retaining structure are engineered structures and will result in
a safer, more stable slope condition than the existing site conditions.
5. The recommendations for the proposed project will result in long term slope stability.
Recommendations include installing stabilizing engineered structures, protecting and
maintaining the vegetation on the slope, and to minimize unnecessary site disturbances.
6. No compensation for impact to wetlands, frequently flooded areas, and fish and
wildlife habitat conservation areas are required since none are disturbed.
7. Monitoring the hazard will be done during the construction since the soil conditions
have to be inspected prior to placing the footings, and during the construction to verify
design conditions are met. Design adjustments may be made to minimize any hazards.
Site Conditions
The terrain slopes steeply to the west at about 32 percent average grade from a near level terrace
on the east half where the existing residence is located. The terrace has existing lawn and
landscaping and there is mix of grasses 'and landscaping shrubs and small to medium trees on the
slope. There is no significant surface drainage on the site, and no seepage on the site. There is
an existing drainage and conveyance system to transport surface discharge from the roof tops and
driveway to the base of the slope to the west. The propc;sed construction site is at about 50
percent grade, which was probably created by placement of fill on the slope from the spoils of
the foundation extations when the house was built since deep fill was found near the top of the
slope.
Local Geology
The subject site lies along a slope forming the edge of the highland plateau of the Edmonds area.
The general stratigraphy (soil layering) of the area is. characterized by fluvial -and glacio-fluvial
sedimend-6om sea -level to around 200 feet, with glacial till and sand deposit plains that make up
the surficial sediments on most of the plateau. The USDA Soil Survey of Snohomish County
maps the soil as Everett gravelly sandy loam and Alderwood gravelly sandy loam. The Everett
soil is deep excessively drained soil on terraces and outwash plains. It is formed in glacial out
wash. The sub -soil is dark brown gravelly sandy loam down to about 60 inches, with increasing
gravel at the deeper depths. The Alderwood gravelly sandy loam is moderately well drained soil
on till plans, moderately deep over a hardpan, and formed in glacial till. Both of these soils are
very stable and suitable for building site development.
This soil has good strength and is not prone to slumps or landslides. It is subject to surface
erosion when exposed to the weather and measures are required to prevent erosion. This soil is
not prone to liquefaction.
The site shows no evidence of landslides or deep soil instability. There were some minor tension
cracks in the soil near the top of the slope, but this was old fill that has been settling and causing
surface irregularities. This does not pose a hazard to this site or the adjoining site, and the slope
will be reinforced with the addition of the proposed structures.
There is no flooding risk on this property. There are no wetlands or surface water on this
property, however several hundred feet down slope there is a wetland at the toe of the slope.
Geotechnics
Surface soils have been inspected over most of the site and on the slopes by visual inspections'.
The underlying undisturbed soil on the subject site is deep silty sand, this is old alluvial outwash.
The soil on the. proposed building site below the existing home is undifferentiated fill I to 4 feet
deep, likely the spoils from the house site excavations. It is a mix of sand and gavel and has
organic material and other debris mixed into it. This was placed at the top of the slope, over
steepening the upper 10 feet or so of the slope.
Soil log 1
�o
Soil Iner 2
Soil log 3
Soil Ingr 4
ed
0 12" mixed fill
11
mix 2
!12"+
0_�o
0-36" mixed fill
mixed
-loam
0-48"+ mixed fill
0- 18 " fill
sand loam
3 6"+ sandy
18"+ sandy loam
UVJLJk Ug L4U1V
Slope stability: Analysis of the natural grade of the steeper parts of the site using the Singh
diagrams indicates that the slope shows a Factor of Safety of 1.8. This reduces to about 1.6 for
dynamic seismic conditions. This indicates a stable slope with a large safety factor over the 1.5
and 1.2 minimum requirements respectively. The upper filled slope is also currently stable, but
with a lower safety factor of about 1.2. This is acceptable for landscaping features, but deeper
footings must be used to get into the underlying original 'subsoil. The soil properties of the
undisturbed Everett soil is as follows: density (gamma)= 130 PCF; Cohesion (C)= 100 PSF,
height of the slope is 50 feet.
Erosion: All of the existing site is well protected from erosion with established vegetation All
of the slopes ov - er 3 0 percent on this site is subject to severe erosion if the soil is exposed.
Minimize disturbing any vegetation on the slope. Any exposed soil on the site must have deep
rooting ground cover installed as soon as practical, avoid concentrated surface flows on the
slopes, and to transport by tight -line roof and driveway runoff to the base of the slope through the
existing drainage system.
23.k060 and 23.80.070 Development standards.
The recommendations in the following section will achieve the following:
1. It will not increase the threat of the geological hazard to adjacent properties beyond
predevelopment conditions; and will reduce them since it will improve the safety factor.
2. It will not adversely impact other any other critical areas.
3. These recommendations 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. All are certified as safe as designed, and under anticipated conditions, by a qualified engineer
licensed in the state of Washington.
Note that construction buffers for the proposed development is zero. The proposed changes will
stabilize the slope to bring the safety factor well above the 1.5 minimum, so no buffers are
required for this project. Therefore section 23.80.070 (1) . does not apply. However, it is
recommended to keep heavy construction equipment back from the top of the slope at least 10
feet during construction.
This proposed development is certified to:
a. Reduce, and not increase surface water discharge or sedimentation to adjacent properties
beyond.predevelopment conditions;
b. It will increase, and not decrease slope stability on adjacent properties; and
c. These alterations will not adversely impact other critical areas;
3. Design Standards. Development within an erosion or landslide hazard area and/or buffer shall
be designed to meet the following:
a. The proposed development has a design safty factor of 1.5 or above static, and 1.2 and above
dynamic, after the recommendations are accomplished. There is no reduction in the safety factor
for the site, or to any adjacent proper -ties.
b. The Structures and improvements are placed to to avoid geologically hazardous areas and to
improve.the slope safety factors, and will have no affect on other critical areas;
c. The proposed structures and improvements minimize alterations to the natural contour of the
slope, and foundations are tiered where possible to conform to existing topography;
d. Structures and improvements are located to preserve the most critical portion of the site and its
natural landforms and vegetation;
e. The proposed development do not result in greater ri�k or a need for increased buffers on
neighboring properties;
f. Retaining walls are used to allow the maintenance of exist
ing natural slope rather than graded
artificial slopes;
g. The development minimizes impervious lot coverage, the proposed building is modest in size;
4. Vegetation Retention. All vegetation on the slopes shall be left undisturbed outside of the
construction area;
5. Seasonal Restriction. Clearing shall be allowed only from May I st to October I st 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;
6. Point Discharges. Point discharges from surface water facilities and roof drains onto or
upstream from erosion or landslide hazard area are prohibited. All roof and surface
discharge shall be collected and tight -lined to the existing site drainage system where it is
conveyed to a an approved discharge point where there is no erosion hazard.
7. Prohibited Development. No On -site sewage disposal systems are proposed for the site.
Recommendations
The proposed building location can be used with a reasonable assurance of long term slope
stability and safety to the building if the following recommendations are followed:
I . Conventional footings may be used as long at it is placed a minimum of 12" into the original
undisturbed sub -soil below the old fill. Bearing capacity is 2000 PSF. Equivalent fluid
pressure of 35 PCF for retaining walls for drained on -site back fill. Coefficient of friction
for the soil is 0.55 and passive soil (lateral bearing) pressure of 350 PCF. All bearing soil
should be inspected by the engineer before concrete is poured.
2. The up hill footings of the accessory structure can be supported on two 24" square x 10"
thick concrete footings, one near each comer of the building. These should be placed below
the fill 12" into original undisturbed subsoil. The footings should be reinforced with (3) #4
rebars in each directions (3" clearance from soil). A 12" diameter Sonotiibe formed concrete
column can be installed on top of these footings up to grade, this should be reinforced with
(4) vertical #4 bars with a #3 horizontal hoops every 6". The excavated soil must be back
filled and compacted over and around these footings up to grade.
3. Roof run-off should be directed to a catch basin in the existing conveyance system and tight -
lined to the base of the slope. No drains or concentrated flows should discharge over the
ground or on the slope.
4. A silt fence should be placed on the downhill side of the construction site to attenuate silt -
laden run-off if necessary. Silt fences should be placed around catch basin inlets. Soil that is*
to be removed and reused around the site should be kept away from the top of the slope.
Soils not to be reused. on the site should be hauled off site to an approved location.
5. The vegetation on the steep slopes should be replaced as soon as practical after construction.
Any disturbed soil in the area of the slope. should be protected with jute matte or straw and
replanted with native vegetation. After final grading any disturbed or exposed soil needs to
have topsoil spread and compacted and planted with'vegetation that will retard erosion and
stabilize the upper soil layers.
Grass seed mixture based on soil type, used for erosion control, should be as follows:
Common Name Percent by Weight
Perennial ryegrass 40
Annual ryegrass 20
Red Fescue 40
This should be applied at a'hydro-seed rate of 1 LB per 1000 sq. ft. (or 60 LB. per acre); or a
hand seed rate for 2 LB. per 1000 sq. ft. (or 87 LB. per acre). Fertilizer shall be 10-20-20,
applied at the rare of 10 LB. per 1,000 sq. ft. (or 400 LB. per acre).
The following native vegetation are acceptable for permanent plantings on disturbed slopes
and buffers:
Trees*( 3-41 size; plant 6' o.c.)
Shrubs*(to be 1-3' size; plant 2 foot
O.C.)
Vine Maple
Kinnick-kinnick
Big leaf maple
Salal
Nobles fir
Snowberry
Grand fir
Vinca Minor
Ore ' gon Grape
Red current
Other native species as recommended by qualified landscape professional knowledgeable in soil
stabilization may also be used.
1%,
let
I
UTYOF EDMONDS - ENGWEERUNUDIVISKON
SPECIAL INS111 ECTION AND TESTING AGREEMENT
IVI, 'e`—
%) 144, 1 1 K-- 1,
4
YXIT
PERN11TH b1d20Y10775. DATE- Jauo 6,20,12
PROJECTSITE, ADDRE SS
PROJECT NA[VIE:
- 9"'Ave N
- cab"1112 and
SPE 1-"( - (C,-
CfAL1N8PECTX01%TAC-'r1,'NCY.
'�:One Win most be completed by each Spec011 Inspection Agency or Inspipetor.
SPECYAL INSPECTIONS WtQUIREb: Special inspections are tequired for this prqjeet,,A applicable, in
accordancQ.with Title IS Edinonds Col-IMILIDity Devclopnient Code (ECDC). When required. the project [Atist
be installed/constrLicte(I per approvcd plans -in([ speciftcations. The owner or the registered design professional
in charge shall einploy an independelit testinglinsli�ctiohi agency/special inspector to perforni require(( special
ills] , )ections. The special inspect6r sliall be a qualified person with competence I"or inspecting the specific type
of construction or operation reqoi.ling special iuspection. The owner, registered professional, contractor and
special inspector/Efgericy shall provide a special inspcction i. eport dQtail ing colnWialic6 with approved plaris and
specifications directly to the Engineering Division.
WORN REQUIUNG SPECIAL INSPEC11ON: Special inspections will be required for the following
categories of work: FOR SPECIFIC INFORMATION REGARD INC, REQUMED SPECIAL 1`14SPECTIONS
SEE THE STATEMENT OF SPF'CfAL INSPECTION NOTED -AS A -CONDIT, ION-OWTHB-B'UIID*fNG-'
PERMITANWOR ON111E APPROVED PLANS.
Soil Conditions Prior to Placing Footings and.
Durim, Construction
6V 0CWifV)T
Retaining Wall Drainage
0�jPWWTII qAn, M",
n
BEFORE A PERMY.fCAN 13E 18813FO: The o,,vp�r and contli'�tZrraiia special irisf;6ct0,x ��fiiilfco,,Qt&trdt
igreementand YCtUU11 to aPernhit Coordinator prior to P.Crinit issuance.
AtIPROVAL OF SPE CIAL INSP8CTORS: Eacli special inspector shall be approved by the Engineering
Divisiou prior to perCorrifing any duties or inspections. The credentials of the specific person perBorming the
iii.spectioiislialibestib.ii-Litted. When applicable; the company p�rforniing inspectiobs must be accredited bythe
American Association of State Higliway and'FransporLation Officials (AASHTO) R1 S.
A. Duties and Respousibilifies, of the Speciall Inspector
1. OBSERVE WORK
"flic.Special inspector shall observe the site work for conibrinwicu with the approved (stamped) plans
-e to be perl'ormcd. Eii needed, -to coafirin that die work being
and specifications. Special iii.SpCction� a,
Completed 111cets spe F
ci.icati.ons� ariclapproved ptalis.
CADoctimejas and '3ettiii&,S\lllccojiiiell�Luc-,iI bitclilet f-ile.,,�\Cotileiit.Otittoolt\i2(i2LQK3\bld2Ot 10775-
(2),citle Revised 00.06.201-2
Work rcqtiirihg special inspection and performance of spec.iat inspectors stlati. be nionitowd by thd
F.rigilicering Division inspector. Engincering.111spectof approval must be obtained prior to placement of
culicrete or other Mnular activities in addition -to that of the specii,11 inspector.
3. FINAL APPRO ' VAL
The Brigincerina Diviii.on may provide finil inspectiou approval,after tile speciat inspecti0ii report(s)
have been s-Lihiniftcd and accepted by the City.
D. Owllel* Responsibififiet,,
1. Theproject owner or the enginecrorarchitect of record actingas the owner.'sagent.shall ftind special
itispection services.
E, lringineee or Architect of -Record RespoMMIRLie-3
1. Prepare Statement of Special impectioti.q.
C -or work that inay not c liforn, to 11,
2. jZeview ffie� speciat inspection reports and provide cor.r ctive action f. 0 e
approved Plans.
ACKNOWLEDGE ME NTS
I have rea(t and ergree to com pith the terins and condillons of tht� agreewlehl-
Owner ntime
(1)[Ca3c print or typc)
Signature Date. -7// el-&, z
(ple.ase print.bi, type)
Signature (f(
Special Inspector/Agenp h. )e
(plefise pt
Da'te
Si -nature
Engineer of Record n1140. i. J!/ (_ r I' U V <
;!7 Date 76 z- 1'2 iw'z-
11� Lz�.
Return the origin,al,signed agreement to:
City of Edmonds Development Services Dcpairtment
1215111 Avenne North, City Hall Second Floor
Edmonds, WA 98020
ACCEPTED BY CIFFY OF EWV:10N�S E
�N
IN.EERING DIVISION:
City Official Siginatare 1. Date
Title- -V\A-
CAL)eounicaLs ind SelthigAniccowiellkLocal S(!uin&s\Teiq)or1ry mteract F.iles\Ct)iitent.ou.ilool(\52Cr2LQI<,3\bld2Oi.107'15--
SI)ecial(iispecLiotiA&recnicnt-Ef\'G(2).doe Revised 06.106.2012
McConnell, Jeanie
From: ericthuesen@frontier.com
Sent: Monday, November 26, 2012 2:59 PM
To: McConnell, Jeanie
Subject: Fw: Fw: bld2011.0775-Thuesen Cabana Revision
Attachments: inspection rev1Jpg; inspection pg3 revl.jpg
Here is the signed inspection form
Please advise how soon I can get the revised permit. I am hopping I can get it tomorrow.
Eric
------ Forwarded Message -----
From: Chopelas & Associates <chopelasandassociates@gmail.com>
To: "ericth uesen @frontier. com" <ericth u esen @frontier. com >
Sent: Monday, November 26, 2012 9:57 AM
Subject: Re: Fw: bld20110775-Thuesen Cabana Revision
attached are page I and 3 that I signed, pg 2 was not affected. I presume they justmant to see my signature on
it since there is no place for me to sign a revision.
Peter
On Mon, Nov 26, 2012 at 7:58 AM, ericthuesen@frontier.com <ericthuesengfrontier.com> wrote:
Peter -Please sign and resend to me this am so I can talk to the City about release of the permit.
Thx
Eric
----- Forwarded Message -----
From: "ericthuesen(a)-frontier.com" <ericthuesena-frontier.com>
To: Chopelas & Associates <chopelasandassociates(cD-qmail.com>
Sent: Saturday, November 24, 2012 10:03 AM
Subject: Fw: bld20110775-Thuesen Cabana Revision
----- Forwarded Message -----
From: "McConnell, Jeanie" <Mcconnell(cD_ci.edmonds.wa.us>
To: "Eric Thuesen (ericthuesenA)frontier.com)" <ericthuesenA_frontibr.com>
Cc: "Clugston, Michael" <cluq�tonA_ci.edmonds.wa.us>; "Thornquist, Linda"
<Thornquist(cD_ci.edmonds.w a.us>
Sent: Wednesday, November 21, 2012 11:34 AM
Subject: b1d20110775-Thuesen Cabana Revision
Eric,
I've signed off on the cabana plan revision which shows the access road, but need for you and your engineer of
record to date and initial the attached revised special inspection and testing agreement. Our permit coordinators
can process the permit for issuance once this revised form is returned to us with signatures.
L]
Thank you,
Jeanie
Jeanie McConnell Y Engineering Program Manager
City of Edmonds I Public Works Department
121 5th Avenue North, Edmonds WA 98020
425.771.0220 x1338 I http://www.edmondswa.jzov/
"Never doubt that a small group of thoughtful, committed citizens can change the world. Indeed, it is the only
thing that ever has." - Margaret Mead<http://www.quotationspage.com/quotes/Marparet Mead>
Thank you,
Jeanie
Jeanie McConnell Y Engineering Program Manager
City of Edmonds I Public Works Department
121 5th Avenue North, Edmonds WA 98020
425.771.0220 x1338 I htt-p://www.edmondswa.gov/
"Never doubt that a small group of thoughtful, committed citizens can change the world. Indeed, it is the only
thing that ever has." - Margaret Mead Mead/>
Peter Chopelas, PE
Engineering & Design Services
307 N. Olympic Ave, Suite 208
Arlington, WA 98223
(360) 653-4615; Chovelasandassociate ail.com
October 25, 2012
Mick Clugston, AICP
City of Edmonds
Development Services Department
1215"' Ave N.
Edmonds, WA 98020
Subject: Order to Correct, October 9'h, 2012; 509 9�h Ave N. Edmonds (BLD20110775)
Dear Mr. Clugston,
'Attached is the revised Geotechnical report and mitigation plan to incorporate the
temporary access road on the west side of the construction site into the recommendations.
I had observed these changes during the various site visits done in July and August, and
approved them because of the unforeseen site conditions as allowed for under the
recommendations of the original geotechcinal report and mitigation plan. At the time, it
was anticipated that slope restoration, within the scope of the existing recommendations,
would have to be done. These kinds of changes during construction on a difficult site are
not unusual.
Nevertheless, specific information is now included into the revised geotech report
and site plan.
. Please extend the Correction dead line since I was unable to respond any sooner.
Mr. Theuesen had forwarded the Order of Correction to me over ten days ago and it was
in my plans to provide the revised information in a timely manner. However I became
very ill and was bedridden during the time I had planned preparing the enclosed
documentation and could not meet the dead line. It was no fault of Mr. Theusesn, he
provide the information I a timely manner attempted to make contact with me several
times. It could not be helped.
If you have any questions, please feel free to call or email me directly.
4(
I W!V,
Peter Chopelas, PE STREET FILE
2-9,2012
SUILDING DEPARTMENT
CITY OF EDMONDS
APes Chopelas, PE
Engineering & Design Services
307 N. Olympic Ave, Suite 208
Arlington, WA 98223
(360) 653-4615; Chopelasandassociates@gmail.com
7
Geotechnical Report,
March 23, 2012
Revised (1): May 15, 2012
Revised (2): October 25, 2012
Eric Thuesen
509_9th Avenue N. STRE T FILE
Edmonds WA 98020 E
Ericthuesen@frontier.com 1-425-772-9401
Subject: g-e-dtechnical investigation for plan ck # 2011-0775 accessory structure (cabana) at the
above address. Revision 2 incorporates mitigation and restoration plan for added access road on
west side of the subject site.
SUMAlARY
A geotechnical investigation of the above property was performed to address slope stability,
erosion -control and drainage issues. This sloping site has been extensively altered due to .
previous construction activities including extensive cut and fill of the slope. A small accessory
structure (cabana) and a retaining wall is proposed to be built below the residence at the top of
slope below the home. The investigation consilsted. of a site inspection to, examine soils and site
conditions and to take measurements on the sites. A review of published material on local
geology from die USDA Soil Survey of Snohomish County, and a review of the geotechnical
report done by Eiennis Bruce PE, dated Jan 13th, 2005 for this site.
. The investigation f6und that the site can be made satisfactory with deep foundations for
the proposed accessory building, and a retaining wall with footings deep enough to get below the
fill, and the use of surface stabilization measures. The building site for the cabana is on shallow
old fill placed at tile top of the slope to make the back yard terrace larger. There is an existing
site drainage system, including yard drains, and a conveyance system that transports all roof and
drive -way run-off to the base of the hill. The fill, though stable for landscaping features, is not
suitable for permanent buildings. Therefore the proposed building and retaining wall should be
built on foundations deep enough to bare on the original undisturbed subsoil. This will allow the
proposed development with a generous safety factor of 1.5 or greater.
These measures will reduce risk of landslides, increase slope stability and will not
increase surface water discharge, sedimentation or erosion on downstream sites. This
development will not increase surface water discharge, and it will not decrease slope stability but
rather increase stability and it will not adversely impact other critical areas.
Durin- the construction phase a temporary access road was constructed on the west side
of the site for movement of construction equipment and supplies to the proposed structures. This
access.road is acceptable for tempo ss, and must be fully removed and soil stabilizing
s�
mea,sur'es be taken after the corRVe M,�ni
�tion to mitigate the disturbed soil.
Peter Chopelas PE
. . . . . . . .... tol
REVUSION
279711
I 4V
C-0
OCT 2 9
'VAL
BUILDING DEPARTMENT
CITY OF EDMONDS
Project Description
The building site is a residential building lot of approximately 0.2 acres served by a municipal
sewer and a public water supply, and with an existing residence and garage built on a terrace on a
sloping site. There is a proposed accessory building of 320 SF, with a 360 SF attached deck, a -
retaining wall and back fill to enlarge the useful backyard, placed at the top of a steep slope
below the existing residence. The building site is about 160 feet from the toeof the slope, and
about 50 feet in elevation above it. The foundation will be deep enough to reach below the old
fill to bear on original undisturbed soil. These are Allowed Activities in a critical area per
23.80.090. B (1). Added to this project is a temporary access road from the west for construction
vehicles to use during the construction phase, and than removed, soil stabilized and replanted.
23.40.120 Mi , tigation sequencing
1. The impact cannot be avoided since it is the property owner's desire to increase the
safety factor of the slope and enlarge the useful available back yard area by adding
engineered fill and building the engineered stepped foundation cabana on the edge of a small
level terrace.
2. The im pacts are minimized by building a modest building and enlarging the useful area
of the back yard by about 300 SF. Site disturbances on the slope should be kept to a
minimum during construction, it should be done during the dry season, and all exposed
soil will be covered during the construction phase. Both temporary and pennanent soil
stabilizing measures are recommended.
3. There are no impacts to welland nor to any habitat area since none are disturbed. The
site will be more stable and surface vegetation restored after the project is completed. .
4. Both the foundation and retaining structure are engineered structures and will result in
a safer, more stable slope condition than the existing site conditions.
5. The recommendations for the proposed project will result in long term slope stability.
Recommendations include installing stabilizing engineered structures, protecting and
maintaining the vegetation on the slope, and to minimize unnecessary site disturbances.
6. No compensation for impact to wetlands, frequently flooded areas, and fish and
wildlife habitat conservation areas are required since none are disturbed.
7. Monitoring the hazard will be done during the construction since the soil conditions
have to be inspected prior to placing the footings, and during the construction to verify
design conditions are met. Design adjustments may be made to minimize any hazards.
ECDC 23.40.240 Unauthorized critical area alterations and enforcement. )
The addition of an access road to the construction site was done to minimize access cost
and reduce damage to other, up -slope existing site features. This kind of field changes
are not unusual in construction sites with difficult access, it was discovered after
extensive excavation that the old fill was much deeper and extensive than determined by
the multiple soil log holes and sampling done prior to construction. There was also a
large amount of contamination and old construction debris buried much deeper than
anticipated. This discovery necessitated a number of field changes to safely -
accommodate the deep and poor quality fill, and to provide alternative access since
excavations were now too deep to access from the top of the site as originally planned.
Because of these changes the City of Edmonds issued an Order to Correct. This is to
incorporate specific instructions into this Geotech report and provide for mitigation of the
disturbed soil on the steep slopes. This temporary access road was observed during
several site inspections and it was found to be stable and acceptable for its intended
temporary use. Specific slope repairs and migrations are recommended when the
construction is completed.
ECDC 23.40.240 C. Minimum Performance Standards for Restoration. .
"2. For alterations toflood and geological hazards, thefollowing minimum performance
standards shall be metfor the restoration of a critical area; provided, that if the violator
can demonstrate that greater safety can be obtained, these standards may be modified.-.
a). The hazard shall be reduced to a level equal to, or less than, the predevelopment
hazard;"
The recommended mitigation will provide lower a reduced level of hazard.since much of
the slope below the construction site was uncontrolled and contaminated fill, with no
specific planting with regard to soil stabilization. The disturbed slope will be compacted,
cut to an acceptable grade, top soil laid and specific plants recommended that will
provide long term slope stability.
"b) Any risk ofpersonal injury resultingftom the alteration shall. be eliminated or
minimized,"
Adding the temporary lower access road on the west reduces the risk to equipment
operators since it provides a clear safe path to the construction site, with lower risk of
slope failure and lost of control of construction equipment as compared to accessing the
site from above. The slope stabilization measures will also leave the slope in a much
more stable and safer condition than leaving it in it original condition.
"And c) The hazard area and buffers shall be replanted with native vegetation sufficient
to minimize the hazard."
The area will be planted with native vegetation that is deep rooting and suitable for*
stabilizing soils, the underlying soil will also be compacted and suitable top soil and
fertilizer to ensure health vegetative cover is established. The restored slope onthe west
of the site will be in safer, more stable and better than its original condition.
Site Conditions
The terrain slopes steeply to the west at about 32 percent average grade from a near level terrace
on the east half where the existing residence is located. The terrace has existing lawn and
landscaping and there is mix of grasses and landscaping shrubs and small to medium trees on the
slope. There is no significant surface drainage on the site, and no seepage on the site. There is
an existing drainage and conveyance system to transport surface discharge from the roof tops and
driveway to the base of the slope to the west. The proposed construction site is on overly steep
slopes at about 50 percent grade, which was created by placement of fill on the slope from the
spoils of the foundation excavations when the original house was built. Deep uncontrolled fill
and depris was found all along the slope during site excavations.
Local Geology
The subject site lies along a slope forming the edge of the highland plateau of the Edmonds area.
The general stratigraphy (soil layering) of the area is characterized by fluvial and glacio-fluvial
sediments from sea level to around 200 feet, with glacial till and sand deposit plains that make up
the surficial sediments on most of the plateau. The USDA Soil Survey of Snohomish County
maps the soil as Everett gravelly sandy loam and Alderwood gravelly sandy loam. The Everett
soil is deep excessively drained soil on terraces and outwash plains. It is formed in glac ial-out
wash. The sub -soil is dark brown gravelly sandy loam down to about 60 inches, with increasing
gravel at the deeper depths. The Alderwood gravelly sandy loam is moderately well drained soil
on till plans, moderately deep over a hardpan, and formed in glacial till. Both of these soils are
very stable and suitable for building site development.
This soil has good strength and is not prone to slumps or landslides. It is subject to surface
erosion when exposed to the weather and measures are required to prevent erosion. This soil is
not prone to liquefaction.
The site shows no evidence of landslides or deep soil instability. There were some minor tension
cracks in the soil near the top of the slope, but this was old fill that has been settling and causing
surface irregularities. This does not pose a hazard to this site or the adjoining site,and the' slope
will be reinforced with the. addition of the proposed structures.
There is no flooding risk on this property. There are no wetlands or surface water on this
property, however several hundred feet down slope there is a wetland at the toe of the slope.
Geotechnics
Surface soils have been inspected over most of the site and on the slopes by visual inspections.
The underlying undisturbed soil on the subject site is deep silty sand, this is old alluvial outwash.
The soil on the proposed building site below the existing home is undifferentiated fill I to 4 feet
deep, likely the spoils from the house site excavations. It is a mix of sand and gravel and has
organic material and other debris mixed into it. This was placed at the top of the slope, over
steepening the upper 10 feet or so of the slope.
Soil log 1
Soil log 2
Soil log 3
Soil log 4
0-12" mixed fill
0-36" mixed fill
0-48"+ mixed fill
0- 18" fill
12"+ sandy loam
36"+ sandy loam
18"+ sandy loam
Soil log table
Subsequent site excavations has revealed much deeper uncontrolled old fill and debris
much deeper than anticipated since the initial soil log explorations. The underlying sub-
soil are as earlier identified, well drained and stable Everett gravelly sandy loam.
Slope stability:. Analysis of the natural grade of the steeper parts of the site using the Singh
diagrams indicates that the slope shows a Factor of Safety of 1.8. This reduces to about 1.6 for
dynamic seismic conditions. This indicates a stable slope with a large safety factor over the 1.5
and 1.2 minimum requirements respectively. The upper filled slope is also currently I stable, but
with a lower safety factor of about 1.2. This is acceptable for landscaping features, but deeper
footings must be used to get into the underlying original subsoil. The soil properties of the
0
0
undisturbed Everett soil is as follows: density (gamma)= 130 PCF; Cohesion (C)= 100 PSF,
height of the slope is 50 feet.
Erosion: All of the existing site is well protected from erosion with established vegetation All
of the slopes over 30 percent on this site is subject to severe erosion if the soil is exposed.
Minimize disturbing any vegetation on the slope. Any exposed soil on the site must have deep
rooting ground cover installed as soon as practical, avoid concentrated surface flows on the
slopes, and to transport by tight -line roof and driveway runoff to the base of the slope through the
existing drainage system.
23.80.060 and 23.80.070 Development standards.
The recommendations in the following section will achieve the following:
1. It will not increase the threat of the geological hazard to adjacent properties beyond
predevelopment conditions; and will reduce them since it will improve the safety factor.
2. It will not adversely impact any other critical areas.
3. These recommendations 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. All are certified as safe as designed, and under anticipated conditions, by a qualified engineer
licensed in the state of Washington.
Note that construction buffers for the proposed development is zero. The. proposed changes will
stabilize the slope to bring the safety factor well above the 1.5 minimum, so no buffers are
required for this project. Therefore section 23.80.070 (1) does not apply. However, it is
recommended to keep heavy construction equipment back from the top of the slope at least 10
feet during construction.
This proposed development is certified to:
I
a. Reduce, and not increase surface water discharge or sedimentation to adjacent properties
beyond predevelopment conditions;
b. It will increase, and not decrease slope stability on adjacent properties; and
c. These alterations will not adversely impact other critical areas;
3. Design Standards. Development within an erosion or landslide hazard area and/or buffer shall
be designed to meet the following:
a. The proposed development has a design safety factor of 1.5 or above static, and 1.2 and above
dynamic, after the recommendations are accomplished. There is no reduction in the safety factor
for the site, or to any adjacent properties.
b. The Structures and improvements are placed to avoid geologically hazardous areas and to
improve the slope safety factors, and will have no affect on other critical areas;
c. The proposed structures and improvements minimize alterations to the natural contour of the
slope, and foundations are tiered where possible to conform to existing topography; temporary
alterations to the slope will be restored to the original natural contour of the slope where
necessary.
d. Structures and improvements are located to preserve and restore the most critical portion of
the site and its natural landforms and vegetation;
e. The proposed development does not result in greater risk or a need for increased buffers on.
neighboring properties;
f. Retaining walls are used to allow the maintenance of existing natural slope rather than graded
artificial slopes;
g. The development minimizes impervious lot coverage, the proposed, building is modest in size-
4. Vegetation Retention. All vegetation on the slopes shall be left undisturbed outside of the
construction area. All disturbed slopes will be restored with native vegitaion.
5. Seasonal Restriction. Clearing shall be allowed only from May I st to October I st 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;
6. Point Discharges. Point discharges from surface water facilities and roof drains onto or
upstream from erosion or landslide hazard area are prohibited. All roof and surface
discharge shall be collected and tight -lined to the existing site drainage system where it is
conveyed to an approved discharge point where there is no erosion hazard.
7. Prohibited Development. No On -site sewage disposal systems are proposed for the site.
Recommendations
The proposed building location can be used with a reasonable assurance of long term slope
stability and safety to the building if the following recommendations are followed:
I . Conventional footings may be used as long at it is placed a minimum of 12" into the original
undisturbed sub -soil below the old fill. Bearing capacity is 2000 PSF. Equivalent fluid
pressure of 35 PCF for retaining walls for drained on -site back fill. Coefficient of friction
for the soil is 0.55 and passive soil (lateral bearing) pressure of 350 PCF. All bearing soil
should be inspected by the engineer before concrete is poured.
Revised recommendations: because of the depth to competent soil, it will be less site
disturbance and provide for more reliable footings to.use driven pin piles. 2" schedule 80
steel pipe should be driven to refusal with a hand held jack hammer. Refusal is achieved
with a driven rate of less than I "per minute. Bearing capacity for each pile is 4,000 lbs.
Driven piles were inspected for refusal before footing placement and found to be acceptable.
2. The up hill footings of the accessory structure can be supported on two 24" square x 10"
thick concrete footings, one near each comer of the building. These should be placed below
the fill 12" into original undisturbed subsoil. The footings should be reinforced with (3) #4
rebars in each directions (Y clearance from soil). A 12" diameter Sonotube formed concrete
column can be installed on top of these footings up to grade, this should be reinforced with
(4) vertical #4 bars with a #3 horizontal hoops every 6". The excavated soil must be back
filled and compacted over and around these footings up to grade. Revised recommendation:
driven piles are also used for all footings since the depth of the old fill was excessive.
3. Roof run-off should be directed to a catch basin in the existing conveyance system and tight -
lined to the base of the slope. No drains or concentrated flows should discharge over the
ground or on the slope
4. A silt fence should be placed on the downhill side of the construction site to attenuate silt -
laden run-off if necessary. Silt fences should be placed around catch basin inlets. Soil that is
to be removed arld reused around the site should be kept away from the top of the slope.
Soils not to be reused on the site should be hauled off site to an approved location.
5. The vegetation on the steep slopes should be replaced as soon as practical after construction.
Any disturbed soil in the area of the slope should be protected with jute matte or straw and
replanted with native vegetation. After final grading any disturbed or exposed soil needs to
have topsoil spread and compacted and planted with vegetation that will retard erosion and
stabilize the upper soil layers.
Grass seed mixture based on soil type, used. for erosion control, should be as follows:
Common Name
Perennial ryegrass
Annual ryegrass
Red Fescue
Percent by Wei2ht
40
20
40
This should be applied at a hydro -seed rate of I LB per 1000 sq. ft. (or 60 LB. per acre); or a
hand seed rate for 2 LB. per 1000 sq. ft. (or 87 LB. per acre). Fertilizer shall be 10-20-20,
applied at the rare of 10 LB. per 1,000 sq. ft. (or 400 LB. per acre).
The following native vegetation are acceptable for permanent plantings on disturbed slopes
and buffers:
Trees*( 34' size; plant 6' o.c.)
Shrubs*(to be 1-3' size; plant 2 foot
O.C.)
Vine Maple
Kinnick-kinnick
Big leaf maple
Salal
Nobles fir
Snowberry
Grand fir
Vinca Minor
Oregon Grape
Red current
Other native species as recommended by qualified landscape professional knowledgeable in soil
stabilization may also be used.
Revised recommendation: where temporary access with heavy equipment was required on any
of the steep slope of the site, compacted temporary fill slopes can stand at 2 to I and the surface
be stabilized with quarry spalls and crushed rock. During periods of inclement weather, all
exposed soil should be covered with mulch, straw, jute mat or weighted plastic sheet. Under no
circumstances should concentrated surface drainage be allowed to discharge over the slopes.
These temporary access roads must be removed by the completion of construction, all grades on
the slope must be restored to the original natural grade contours (before the old existing fill) of
no more than 2 to 1, all surface soils machine compacted, and top soil spread with mulch and jute
mate used to temporary hold top soil in place until vegetation is established. Plants from the
above list must be installed on all disturbed areas on the slope.
4t
I
C
0
9
Peter Chopelas, PE
Engineering & Design Services
307 N. Olympic,Ave, Suite 208
Arlington, WA 98223
(360) 653-4615; Chopelasandassociates@gmail.com
Mitigation Plan
May 17, 2012 per section 23.40.130
Revised: October 25, 2012
Eric Thuesen
509-9'h Avenue N.
Edmonds WA 98020
Ericthuesen@frontier.com
Subject: Slope stabilization measures for plan ck # 2011-0775 accessory structure (cabana) at
the above address
Project Description
The building site is a residential building lot of approximately 0.2 acres served by a municipal
sewer and a public water supply, and with an existing residence and garage built on a terrace on a
sloping site. There is a proposed accessory building of 320 SF, with a 360 SF attached deck, a
retaining wall and back fill to enlarge the useful backyard, placed at the top of a steep slope
below the existing residence. The building site is- about 160 feet from the toe of the slope, and
about 50 feet in elevation above it.
Goals and Objectives
The project will reduce potential landslides, stabilize the existing slope, enhance erosion
control on the steep slopes, and will enhance and add to native vegetation on the -hillside.
1. Potential impacts are uncontrolled run-off, erosion and destabilizing the slope during
construction phase. There is new impervious area proposed and the additional loads on
the slopes created by the proposed structures. These will be mitigated by using an
engineered design, construction timing, limiting disturbing the slope to betwe en May I
and October I't, use of a silt fence on the down hill side of the site disturbance, cover any
exposed soils on the slopes within 48 hours. -Permanent measures will be to direct roof
run-off to the existing stormwater conveyance system, and replanting disturbed soil with
native vegetation suitable for soil stabilizing surface soils.
There are no wetlands, habitat, or shorelines affected by this project, so no habitat
mitigation measures are necessary. However, replanting of the hillside with native
vegetation will enhance the natural environment and provide for improved habitat.
2. Slope stability measurements were done using traditional Singh diagrams. This has
been in use for many decades and has proven to result in safe and stable slopes. This
methodology results is a more stable slopes as indicated by more modem analysis
methods.
0
0
3. If all recommendations are followed, the likelihood.of success are estimated to me 98
percent or greater. The methods proposed have long histories of successful outcomes.
4. Only steep slope areas are affected by this proposal, all mitigation is oriented towards
steep slope development. All off site impacts will be prevented by following the
recommendations in the Geotech report.
B. Performance Standards. Regular inspections of the site must be made to insure that off
site run-off avoided by containing all surface run-off on -site during construction. And
that those construction recommendations are followed.
C. Detailed Construction Plans: These are detailed in the Recommendations section of the
Geotech report. These include:
I . Conventional grading and footings recommendations. And all bearing soil should be
inspected by the engineer before concrete is poured.
Revised recommendations: because of the depth to competent soil, it will be less site
disturbance and provide for more reliable footings to use driven pin piles. 2" schedule
80 steel pipe should be driven to refusal with a hand held jack hammer. Refusal is
achieved with a driven rate of less than I "per minute. Bearing capacity for each pile. is
4,000 lbs. Driven piles were inspected for refusal before footing placement and found to
.be acceptable.
2. Roof run-off should be directed to a catch basin in the existing conveyance system and
tight -lined to the base of the slope. No drains or concentrated flows should discharge
over the ground or on the slope.
3. A silt fence should be placed on the downhill side of the construction site to attenuate
silt -laden run-off.if necessary.. Silt fences should be placed around catch basin inlets.
Soil that is to be removed and reused around the site should be kept away from the top of
the slope. Soils not to be reused on the site should be hauled off site to an approved
location. Clearing shall be allowed only from May I st to October I st 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.
4. The vegetation on the steep slopes should be replaced as soon as practical after
construction. Any disturbed soil in the area of the slope should be protected withjute
matte or straw and replanted with native vegetation. After final grading any disturbed or
exposed soi ' I needs to have topsoil. spread and compacted and planted with vegetation
that will retard erosion and stabilize the upper soil layers.
Grass seed mixture based on soil type, used for erosion control, should be as follows
Common Name
Perennial ryegrass
Annual ryegrass
Red Fescue
Percent by Weight
40
20
40
This should be applied at a hydro -seed rate of I LB per 1000 sq. ft. (or 60 LB. per acre);
or a hand seed rate for 2 LB. per 1000 sq. ft. (or 87 LB. per acre). Fertilizer shall be 10-
20-20, applied at the rare of 10 LB. per 1,000 sq. ft. (or 400 LB. per acre).
The following native vegetation are acceptable for permanent plantings on disturbed
slopes and buffers: I -
Trees*( 3-4' size; plant 6' o.c.)
Shrubs*(to be 1-3' size; plant 2 foot
O.C.)
Vine Maple
Kinnick-kinnick
Big leaf maple
Salal
Nobles fir
Snowberry
Grand fir
Vinca Minor
Oregon Grape
Red current
Other native species as recommended by qualified landscape professional knowledgeable in soil
stabilization may also be used.
Revised recommendation: where temporary access with heavy equipment was required on any
of the steep slope of the site, compacted temporary fill slopes can stand at 2 to I and the surface
be stabilized with quarry spalls and crushed rock. During periods of inclement weather, all
exposed soil should be covered with mulch, straw, jute mat or weighted plastic sheet. Under no
circumstances should concentrated surface drainage be allowed to discharge over the slopes.
These temporary access roads must be'removed by the completion of construction, all grades on
the slope must be restored to the original natural grade contours (before the old existing fill) of
no more than 2 to 1, all surface soils machine compacted, and top, soil spread with mulch and jute
mate used to temporary hold top soil in place until vegetation is established. Plants from the
above list must be installed on all disturbed areas on the slope.
D. Monitoring Program. Inspections should ' be doiie during the construction at each
phase, and upon completion of the replanting of the exposed soil. It should not be
necessary to monitor the health of the vegetati ' on for more than one year after completion.
If the plants are growing, healthy, and providing ground cover, no further action should
be necessary.
E. Contingency Plan. Project modifications may have to be done if unforeseen soil
conditions occur during the soil and excavation inspections, or if unusually wet weather
or soil conditions are encountered.
Note: the revised recommendations above were as a result of finding unforeseen soil
conditions after construction excavations. These kind of contingencies were
accommodated within the original recommendations.
F. Financial Guarantees. Applicant will post bonds, or a pledge of financial responsibility
(at the director's option) to ensure mitigation, maintenance, and monitoring. [Ord. 3527
§ 2, 2004]. The size of this project is not sufficient to require extensive bonds.
0
CITY OF EDMONDS
DEVELOPMENt SERVICES DEPARTMENT
121 5th Avenue North, Edmonds, WA 98020
NOTICE OF VIOLATION AND
MONETARY FINE
Location of Violation (Address and/or description of location): Parcel Numbers 27032400225200,
and 27032400225 100 which are addressed as 514 8h Avenue North and 509 9th Avenue North,
Edmonds, WA 98020
Issued To: Eric Thuesen
Address Of Person This Order Is Issued To: 509 Wh, Avenue North, Edmonds, WA 98020
Code Sections Violated: Edmonds Community Development Code (ECDC) ECDC 23.40.040 �-
Jurisdiction; ECDC 23.40.220 — Allowed Activities; ECDC 23.40.230 — Exemptions; ECDC 23.80.040
— Allowed activities — Geologically hazardous areas.
Description of Viodation: As note d in the associated Order to Correct issued on October 9, 2012, a
building p�rmit for the construction of a cabana and retaining wall at 569 91h Avenue North was issued
to Mr. Thuesen on June 28, 2012 (BLD20110775). At a site inspection on July 30, 2012, it was noticed
that a dirt access road had been created from 8th Avenue North to the west of the cabana site apparently
in order to provide access for construction vehicles to get to the work area. The area west of the cabana
construction site is a steep slope area qualifying as both erosion and landslide hazar/d areas, as was
indicated in the geotechnical report associated with the cabana permit. All alterations to critical areas
(i.e. erosion and landslide hazard areas) must be approved by the City per ECDC 23.40.220, unless the
activity is exempt per ECDC 23.40.230.
Based on subsequent review of the building permit information, however, it was found that the dirt
access road was not shown on the approved site plan for the building permit nor was it discussed or
-mitigated for in the associated geotechnical report. In short, the creation of the dirt access road was not
within the scope of the underlying permit for the cabana and retaining wall., The dirt access road was
therefore created in an erosion and landslide hazard area without first obtaining the proper approval
from the City in violation of city code. (ECDC 23.40.220; ECDC 23.40.230; ECDC 23.80.040). A
subsequent field inspection on September 21, 2012 verified these conditions at the site.
Corrective Action Required: In addition to the timely payment of any monetary penalties imposed as
a result of this Order, Mr. Thuesen shall submit a restoration plan for the site as a revision to
BLD20110775 as was described in the associated Order to Correct issued on October 9. 2012. The dirt
road area shall remain unused and shall remain stabilized until a revision to BLD20110775 is approved
by the City.
In accordance with ECDC 23.40.240.13, the restoration plan for the dirt road area must meet the
minimum standards identified in ECDC 23.40.240.C.2. The plan, and an updated geotechnical report,
must meet the development criteria found in ECDC Chapter 23.80, specifically in ECDC 23.80.060 and
23.80.070. Any and all work required to restore. the property, including all work done in preparing the
restoration plan itself, shall be paid for by Mr. Thuesen in accordance with ECDC 23.4.0.240.A.
----------- -- ------------- ....... -------------- -
I I P a - e
0 .0
The restoration plan, updated geotechnical report, and any other required information shall be submitted
as a revision to the original cabana building permit (BLD20110775). If an access road from the west is
proposed to be used again in the future, Mr. Thuesen shall include that information in the revision
'showing the road on the plans while updating the associated geotechnical report to discuss the
construction of the road and its impact on the steep slope area, including post -cabana construction
mitigation for the road area.
No vehicles shall access the cabana site from the west until a revision to building permit BLD20110775
and the associated geotechnical report are reviewed and approved by the City.
Correction is Required no later than: November 5, 2012. As noted in the associated Order to
Correct issued on October 9, 2012, correction of the referenced violation was required by October 23,
2012. VAiile it is noted that the Applicant has stabilized the site using best practices for erosion and
sediment control, the City has not received the required restoration plan prepared as part of a revision to
BLD20110775. Therefore, the City of Edmonds is issuing this Notice of Civil Violation pursuant to
ECDC 20.1.10.040.13 and monetary penalties will begin to accrue on October 24, 2012. A $100 per day
fine will be assessed in accordance with ECDC 20.110.040.F beginning on October 24, 2012, for each
and every day or portion of a day on which the violation continues.
If any required work to correct the violations(s) in this Order is not commenced or completed within the
time specified by this notice and order, the City -may proceed to file a lawsuit to obtain a warrant to
abate the violation and cause the work to be done. and charge the costs thereof as a lien against the
property and as a joint and several personal obligation of any persons responsible for code compliance.
Or, the City may file a lawsuit against the homeowner to obtain a warrant for abatement or an injunction
to stop continuing violation(s). r
If any assessed penalty, fee or cost is not paid on or before the due date, the City may charge the unpaid
amount as a lien against the property where the civil code violation occurred if owned by a person
responsible for code compliance and as joint and several personal obligations of all persons responsible
for code compliance.
Costs of pursuing code enforcement and abatement incurred to correct a code violation that exceed the
amount of the penalty may also be assessed against the person to whom the notice and order is directed.
Such costs include legal and i ' ncidental expenses to the extent that these costs exceed the amount of the
penalty paid. Such costs are due and payable thirty days from mailing of the invoice.
Appeal of This Order: In accordance with ECDC 20.110.040.C, this decision is appealable to the City
of Edmonds Hearing Examiner by filing a complete appeal application including written notice of
appeal with the Development Services Director no later than November 5, 2012 at 4:30 pm. The gppeal
filing fee is $705 and full payMent of this fee must accompany the written notice of gappeal. The Notice
of Appeal shall comply with the rules set forth in the ECDC or the appeal may be dismissed by the
Hearing Examiner.
Enforcement of this Notice and Order shall be stayed as to the appealing party during the pendency of
any administrative appeal, except when the Director determines that the violation poses a significant
threat of immediate and/or irreparable harin and so states in tile Notice and Order.
Upon motion of the City, the Hearing Examiner may assess the costs of an appeal hearing including but
not limited to, the hearings examiner's fees and reasonable costs of staff time, if the Hearing Examiner
finds the appeal was frivolous. Any appellant who fails to appear at his or her appeal hearing, unless for
good cause shown, shall be responsible for the hearings examiner's costs.
Failure to Appeal This Order: Failure to appeal a Notice of Civil Violation and Order as provided in
this subsection constitutes as waiver of all rights to an administrative hearing and determination of the
- --- - --------- - ----- - ----- -- ------- ------------- - - ------- — ------ ... ....
2 P a e
0 0
matter. Failure to appeal shall render the Notice of Civil Violation and Order a final determination that
the conditions described in the'Notice and Order existed and constituted a civil code violation, and that
the named party or parties is (are) liable as a person(s) responsible for code compliance.
This Notice and Order are imposed without prejudice to any other civil, criminal, injunctive or other
remedy and/or penalty available to the City.
Date Posted: N/A Date Mailed: October 24, 2012 Date Served: N/A
Issuing Party: Mike Clugston, AICP Title: Associate Planner
Signature:
!2
3 1 P a g e
CITY OF EDMONDS
DEVELOPMENT SERVICES DEPARTMENT
121 5th Avenue North, Edmonds, WA 98020
ORDER TO -CORRECT
Location of Violation (Address and/or description of location): Parcel Numbers 27032400225200,
and 27032400225 100 which are addressed as 514 8b Avenue North and 509 91h Avenue North,
Edmonds, WA 98020
Issued To: Eric Thuesen
Address Of Person This'Orderls Issued To: 509 9th Avenue North; Edmonds, WA 98020
Code Sections Violated: Edmonds Community Development Code (ECDC) ECDC 23.40.040 —
Jurisdiction; ECDC 23.40.220 — Allowed Activities; ECDC 23.40.230 — Exemptions; ECDC 23.80.040
— Allowed activities — Geologically hazardous areas.
Description of Violation: A building permit for the construction of a cabana and retaining wall at 509
9th Avenue North was issued to Mr. Thuesen on June 28, 2012 (BLD20110775). At a site inspection on
July 30, 2012, it was noticed that a dirt access road had been created from 8 1h Avenue North to the west
of the cabana site apparently in order to provide access for construction vehicles to get to the work area.
The area west of the cabana construction site is a steep slope area qualifying as both erosion and
landslide hazard areas, as was indicated in the geotechnical report associated with the cabana pen -nit.
All alterations to critical areas (i.e. erosion and landslide hazard areas) must be approved by the City per
ECDC 23.40.220, unless the activity is exempt per ECDC 23.40.230.
Based on subsequent review of the building permit information, however, it was found that the dirt
access road was not shown on the approved site plan for the building permit nor was it discussed or
mitigated for in the associated geotechnical report. In short, the creation of the dirt access road was not
-within the scope of the underlying permit for the cabana and retaining wall. The dirt access road was
therefore created in an erosion and landslide hazard area without first obtaining the proper approval
from the City in violation of city code. (ECDC 23.40.220; ECDC 23.40.230; ECDC 23.80.040). A
subsequent field inspection on September 21, 2012 verified these conditions at the site.
Corrective Action Required: Because the creation of the dirt access road by Mr. Thuesen was not
within the scope of the permit he obtained for the construction of the cabana and retaining wall, it is
considered an alteration to a critical area without approval of the City. ECDC 23.40.240 governs the
process Mr. Thuesen is required to follow in order to correct the violation.
In accordance with ECDC 23.40.240.A, Mr. Thuesen, and his contractors, shall immediately stop using
the dirt road east of the rock spall-covered access and stabilize the area in accordance with the code.
The stabilization requirements are contained within the 2005 Department of Ecology stormwater
manual, as implemented by ECDC 18.30. This manual provides that the dirt road area shall be
stabilized with appropriate erosion and sediment control BMPs including,but not limited to, silt fencing,
jute mat, straw or hydroseeding in accordance with seasonal soil stabilization requirements.
-1
Pursuant to ECDC 23.40.240.B, all use of this dirt road shall cease until Mr. Thuesen prepares a
restoration plan in accordance with the provisions of this code and that plan is then approved by the
Director. In accordance with ECDC 23.40.240.B, the restoration plan for the dirt road area must meet
---------------------------- --- ----------------------- ------------------------------- ----------------------------------- - -------
I I P 6 C, e
the minimum standards identified in ECDC 23.40.240.C.2. The plan, and an updated geotechnical
report, must meet the development criteria found in ECDC Chapter 23.80, specifically in ECDC*
23.80.060 and 23.80.070. Any and all work required to restore the property, including all work done in
preparing the restoration plan itself, shall be paid for by Mr. Thuesen in accordance with ECDC
23.40.240.A.
The restoration plan, updated geotechnical report, and any other required information shall be submitted
as a revision to the original cabana building permit (BLD20110775). If an access road from the west is
proposed to be used.again in the future, Mr. Thuesen shall include that information in the revision
showing the road on the plans while updating the associated geotechnical report to discuss the
construction of the road and its impact on the steep slope are�a, including post -cabana construction
mitigatio'n for the road area.
No vehicles shall access the cabana site from the west until a revision to building permit BLD20110775
and the associated geotechnical report are reviewed and approved by the City.
Correction is Required no later than: October 23, 2012. As noted above, the use of the dirt road
area shall cease immediately and the road area shall be stabilized with appropriate erosion and sediment
control. A restoration plan (prepared as part of a revision to BLD20110775) shall be filed with the City
by October 23, 2012. If the required information is not received by October 23, 2012, a Notice of Civil
Violation will be issued pursuant to ECDC 20.410.040.13 and monetary penalties will begin to accrue
on October 24, 2012. A $100 per day fine will be assessed in accordance with ECDC 20.110.040.17
beginning on October 24, 2012, for each and every day or portion of a day on which the violation
continues. A Notice of Civil Violation may be appealed in accordance with ECDC 20.110.040.C.
This. Order to Correct is imposed without prejudice to any other civil, criminal, injunctive or other
remedy and/or penalty available to the City.
Date Posted: - N/A Date.Mailed: NA Date Served: October 9. 2012
Issuing Party: Mike Clugston, AICP Title: Associate Planner
Signature:
2 1 P a e
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26 E V I'
ELOPA04EI
C U1 VT S
VTERE:i�VICES
E D
SPECIAL INSPECTION AND TESTING AGREEMENT
31�;
Permit #: 90 2-0 1101 Project: c Co C��
Prior to issuance of a permit, this form must he completed in its entirety and returned to the Cityfor U)-
approval. The completedform must have signatures of acknowledgment by allparties. -;-4
Special Inspection Firm and Special
DUTIES AND RESPONSIBIELITIES
Inspectors:
CITY
COPY
C\Aopz� vC,
The Special Inspection f= of
will perform
special
inspection for the fol lowing types
of work separate forins must be submitted if more than one firm is to be --n
employed):
amp==
r"O"
• Reinforced Concrete
0 Spray applied Fireproofing
M
• Bolting in, Concrete
0 Smoke Control Systems
• Prestressed Concrete
0 Lateral Wood
• Sbotcrete
0 Structural Observation
• Structural Masonry
Grading/soils e�fo' ��c C"
• Structural Steel/Welding
'94 Other bCzk4-"C'J J�
P-r'of -e<)
(*-10V C �kddk
• High Strength Bolting
0 Other
All individual inspectors to be employed on this project will be WABO certified for the type of work they are to
inspect. If inspection is for work that is not covered by the WABO categories, or the inspector is not WABO
certified, a detailed resume of the inspector and firm must be submitted. The resurne must show fhat the
inspector and the firin are qualified by education and experience to perform. the work and testing required by the
project design and specifications.
The work shall be inspected for conforniance with the plans and specifications approved by the City. Revisions
and addenda sheets will not be used for inspection, unless they have been approved bythe City. hispection
recor ds shall include:
A daily record to be maintained on site, itemizing the inspections performed. Any nonconforming work
shall be brought to the immediate attention of the contractor forresolution.
A weekly report shall be submitted to the City; detailing the inspections and testing performed, listing
any rionconforming work and resolution of noriconforining items.
A final report shall be submitted to the building department prior to the Certificate of Occupancy being
issued. This report will indicate that inspection and testing was completed in conformance with the
approved plans, specifications and approved revisions or addenda. Any unresolved discrepancies must
be detailed in the final report.
LABuilding New Folder 201 fforrns\Special inspection forin.doel0/21/201 .01 STREET FILE
RECEIVED
IN 26 2012
'DEVELOPMENT SERVICES
COUNTER
Contractor:
The contractor shall provide the special inspector or agency adequate notification of work requiring inspection.
The City approved plan and specifications must be made available, at the. jobsite far the use of the special
inspector and the City inspector. The contractor shall maintain all daily inspection reports, on site, for review by
all parties,
The special inspection functions are considered to be in addition to the normal inspections performed by the City
and the contractor is,responsible for contacting the City to schedule regular inspections. No concrete shall be
poured or other work covered until approval is given by the City inspector.
BuildinjZ De�me�nt
The building department shall review any revisions and addenda. The City inspector will monitor the special
inspection functions for compliance with the agreementand the approvedplans. The City inspector shall be
responsible for approving various stages of construction to be covered and for work to proceed.
Desi�!n Professionals:
The architect and/or engineer will clearly indicate on the plans and specifications the specific types of special
inspection required. and shall include a schedule for inspection and testing. The architect and/or engineer will
coordinate their revision and addenda process 'in such a way as to insure that all required City approvals are
obtained, prior to work shown on the revisions being performed in the field.
Owner:
The project owner, or the architect or engineer acting as the owners agent, shall employ the special inspector or
agency.
ENFORCEMMNT
A failure of the special inspector or firm to.perform in keeping with the requirements of the UBC, the approved
plans and this document, may void this agreement and th e Building Official's approval of the special inspector.
0
hi such a case a new special inspector and/or'firrn would need to be proposed for approval. A failure of the
design and/or construction parties to perform in accordance with this agreement may result 'in a STOP WORK
notice being posted on the project until nonconforming items have been resolved.
ACKNOWLE DGMIENTS
I have read and agr ee to comply with the terms and conditions of this agreement.
Date 6 12,112-OIZ—
Owner: Signature ��,6
E�� -ure Date:
Contractor: S ex,� Signat
Axch./Ena: 10. PQ-lh& PC- Signature Date:
&LMSpecial Jnsp. Signature*,� D ate: Lie I
ACCEPTED FOR THE CITY OF EDMONDS
Date:
y: j�4�
Eveli, I
f!e�t
LABuilding New Folder 2010\Fo1-ms\Spccia1 inspection forrn.docl 0/21/2010 -
0
APeter Chopelas, PE
Engineering & Design Services
H7 N. Olympic Ave, Suite 208
Arlington, WA 98223
(360) 653-4615; Chopelasandassociates@gmai'l.com
Geotechnical Report
March 23, 2012
Revised: May 15, 2012
Eric Thuesen XXD �IY 1/11G
509-9'h Avenue N.
Edmonds WA 98020
Ericthuesen@frontier.com
1-425-772-9401
Subject: geotechnical investigation for plan ck # 2011-0775 accessory structure (cabana) at the
above address
SUADIARY
A geotechnical investigation of the above property was performed to address slope stability,
erosion control and drainage issues. This sloping site has been extensively altered due to
previous construction activities including extensive cut and fill of the slope. A small accessory
structure (cabana) and a retaining Wall is proposed to be built below the residence at the top of
slope below the home. The investigation consisted of a site inspection to examine soil s* and site
conditions and to take measurements on the sites. A review of published material on local
geology from the USDA Soil Survey of Snohomish County, and a review of the geotechnical.
report done by Dennis Bruce PE, dated Jan 13th, 2005 for this site.
The investigation found that the site can be made satisfactory with deep foundations for the
proposed accessory building, and a retaining wall with footings deep enough to get below the fill,
and the use of surface stabilization measures. The building site for the cabana is on shallow old
fill placed at the top of the slope to make the �ack yard terrace largef. There is an existing site
drainage system, including yard drains, and a conveyance system that transports all roof and
driveway run-off to the base of the hill. The fill, though stable for landscaping features, is not
suitable for permanent buildings. Therefore the proposed building and retaining wall should be
built on foundations deep enough to bare on the original undisturbed subsoil. This will allow the
proposed development with a generous safety factor of 1.5 or greater.
These measures will reduce risk of landslides, increase slope stability and will not increase
surface water discharge, sedimentation or erosion on downstream sites. This development will
not increase surface water discharge, and it will not decrease slope stability but rather increase
stability and it will not adversely impact-- - r4g W-ical areas.
.Q.ft -
Peter Chopelas PE
WAS
W h
�_c
�n
r000"
M
72, W MAY 2 9 2012
27274
BUILDING DEPARc.-MENT
CITY OF EDMONDS
AL
-775;
OLD 2-o) 2-' -�)
Project Description
The building site is a residential building lot of approximately 0.2 acres served by a municipal ,
sewer and a public water supply, and with an existing residence and garage built on a terrace on a
sloping site. There is a proposed accessory building of 320 SF, with a 360 SF attached deck, a
retaining wall and back fill to enlarge the useful backyard, placed at the top of a steep slope
below the existing residence. The building site is about 160 feet from the toe of the slope, and
about 50 feet in elevation above it. The foundation will be deep enough to reach below the old
fill to bear on original undisturbed soil. These are Allowed Activities in a critical area per
23.80.090. B (1).
23.40.120 Mitigation sequencing.
1. The impact cannot be avoided since it is the property owner's desire to increase the
safety factor of the slope and enlarge the useful yard area by adding an engineered
retaining wall and building the cabana with an engineered foundation on the edge of a
small level terrace.
2. The impacts are minimized by building a modest building and enlarging the useful area
of the backyard by about 300 SF. Site disturbances on the slope should be kept to a
minimum during construction, it should be done during the dry season, and all exposed
soil will be covered during the construction phase. Both temporary and permanent soil
stabilizing measures are recommended.
3. There are no impacts to wetland nor to any habitat area since none are disturbed. The
site will be more stable and surface vegetation restored after the project is completed.
4. Both the foundation and retaining structure are engineered structures and will result in
a safer, more stable slope condition than the existing site conditions.
5. The recommendations for the proposed project will result in long term slope stability.
Recommendations include installing stabilizing engineered structures, protecting and
maintaining the vegetation on the slope, and to minimize unnecessary site disturbances.
6. No compensation for impact to wetlands, frequently flooded areas, and fish and
wildlife habitat conservation areas are required since none are disturbed.
7. Monitoring the hazard will be done during. the construction since the soil conditions
have to be inspected prior to placing the footings, and during the construction to verify
design conditions are met. Design adjustments may be made to minimize any hazards.
Site Conditions
The terrain slopes steeply to the west at about 32 percent average grade from a near level terrace
on the east half where the existing residence is located. The terrace has existing lawn and
landscaping and there is mix of grasses and landscaping shrubs and small to medium trees on the
slope. There is no significant surface drainage on the site, and no seepage on the site. There is
an existing drainage and conveyance system to transport surface discharge from the roof tops and
driveway to the base of the slope to the west. The propdsed construction site is at about 50
percent grade, which was probably created by placement of fill on the slope from the spoils of
the foundation excavations when the house was built since deep fill was found near the top of the
slope.
Local Geology
The subject site lies along a. slope forming the edge of the highland plateau of the Edmonds area.
The general stratigraphy (soil layering) of the area is characterized by fluvial and glacio-fluvial
sediments from sea level to around 200 feet, with glacial till and sand deposit plains that make up
the surficial sediments on most of the plateau. The USDA Soil Survey of Snohomish County
maps the soil as Everett gravelly sandy loam and Alderwood gravelly sandy loam. The Everett
soil is deep excessively drained soil on terraces and outwash plains. It is formed in glacial out
wash. The sub -soil is dark brown gravelly sandy loam down to about 60 inches, with increasing
gravel at the deeper depths. The Alderwood gravelly sandy loam is moderately well drained soil
on till plans, moderately deep over a hardpan, and formed in glacial till. Both of these soils are
very stable and suitable for building site development.
This soil has good strength and is not prone to slumps or landslides. It is subject to surface
erosion when exposed to the weather and measures are required to prevent erosion. This soil is
not prone to liquefaction.
The site shows no evidence of landslides or deep soil instability. There were some minor tension
cracks in the soil near the top of the slope, but this was old fill that has been settling and causing
surface irregularities. This does not pose a h azard to this site or the adjoining site, and the slope
will be reinforced with the addition of the proposed structures.
There is no flooding risk on this property. There are no wetlands or surface water on this
property, however several hundred feet down slope there is a wetland at the toe of the slope.
Geotechnics
Surface soils have been inspected over most of the site and on the slopes by visual inspections.
The underlying undisturbed soil on the subject site is deep silty sand, this is old alluvial outwash.
The soil on the proposed building site below the existing home is undifferentiated fill I to 4 feet
deep, likely the spoils from the house site excavations. It is a mix of sand and gavel and has
organic material and other debris mixed into it. This was placed at the top of the slope, over
steepening the upper 10 feet or so of the slope.
Soil log I
Soil log 2
Soil log 3
Soil log 4
0-12" mixed fill
0-36" mixed fill
—
0-48"+ mixed fill
0- 18" fill
12"+ sandy loam
3 6"+ sandy-loa
18"+ sandy loam
Soil log table
Slope stability: Analysis of the natural grade of the steeper parts of the site using the Singh
diagrams indicates that the slope shows a Factor of Safety of 1.8. This reduces to about 1.6 for
dynamic seismic conditions. This indicates a stable slope with a large safety factor over the 1.5
and 1.2 minimum requirements respectively. The upper filled slope is also currently stable, but
with a lower safety factor of about 1.2. This is acceptable for landscaping features, but deeper
footings must be used to get into the underlying original 'subsoil. The soil properties of the
undisturbed Everett soil is as follows: density (gamma)= 130 PCF; Cohesion (C)= 100 PSF,
height of the slope is 50 feet.
Erosion: All of the existing site is well protected from erosion with established vegetation All
of the slopes over 30 percent on this site is subject to severe erosion if the soil is exposed.
Minimize disturbing any vegetation on the slope. Any exposed soil on the site must have deep
rooting ground cover installed as soon as practical, avoid concentrated surface flows on the
slopes, and to transport by tight -line roof and driveway runoff to the base of the slope through the
existing drainage system.
23A.060 and 23.80.070 Development standards.
The recommendations in the following section will achieve the following:
1. It will not increase the threat of the geological hazard to adjacent properties beyond
predevelopment conditions; and will reduce them since it will improve the safety factor.
2. It will not adversely impact other any other critical areas.
3. These recommendations 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. All are certified as safe as designed, and under anticipated conditions, by a qualified engineer
licensed in the state of Washington.
Note that construction buffers for the proposed development is zero. The proposed changes will
stabilize the slope to bring the safety factor well above the 1.5 minimum, so no buffers are
required for this project. Therefore section 23.80.070 (1) does not apply. However, it is
recommended to keep heavy construction equipment back from the top of the slope at least 10
feet during construction. I
This proposed development is certified to:
a. Reduce, and not increase surface water discharge or sedimentation to adjacent properties
beyond predevelopment conditions;
b. It will increase, and not decrease slope stability on adjacent properties; and
c. These alterations will not adversely impact other critical areas;
3. Design Standards. Development within an erosion or landslide hazard area and/or buffer shall
be designed to meet the following:
a. The proposed development has a design safty factor of 1.5 or above static, and 1.2 and above
dynamic, after the recommendations are accomplished. There is no reduction in the safety factor
for the site, or to any adjacent properties.
b. The Structures and improvements are placed to to avoid geologically hazardous areas and to
improve the slope safety factors, and will have no affect on other critical areas;
c. The proposed structures and improvements minimize alterations to the natural contour of the
slope, and foundations are tiered where possible to conform to existing topography;
d. Structures and improvements are located to preserve the most critical portion of the site and its
natural landforms and vegetation;
e. Th e proposed development do not result in greater ri�k or a need for increased buffers on
neighboring properties;
f, Retaining walls are used to allow the maintenance of existing natural slope rather than graded
artificial slopes;
g. The development minimizes impervious lot coverage, the proposed building is modest in size;
4. Vegetation Retention. All vegetation on the slopes shall be left undisturbed outside of the
construction area;
5. Seasonal Restriction. Clearing shall be allowed only from May I st to October I st of each year;
prov ided, that the director may extend or shorten the dry season on a case -by -case basis
depending on actual weather conditions;
6. Point Discharges. Point discharges from surface water facilities and roof drains onto or
upstream from erosion or landslide hazard area are prohibited. All roof and surface
discharge shall be collected and tight -lined to the existing site drainage system where it is
conveyed to a an approved discharge point where there is no erosion hazard.
7. Prohibited Development. No On -site sewage disposal systems are proposed for the site.
Recommendations
The proposed building location can be used with a reasonable assurance of long term slope
stability and safety to the building if the following recommendations are followed:
I . Conventional footings may be used as long at it is placed a minimum of 12" into the original
undisturbed sub -soil below the old fill. Bearing capacity is 2000 PSF. Equivalent fluid
pressure of 35 PCF for retaining walls for drained on -site back fill. Coefficient of friction
for the soil is 0.55 and passive soil (lateral bearing) pressure of 350 PCF. All bearing soil
should be inspected by the engineer before concrete is poured.
2. The up hill footings of the accessory structure can be supported on two 24" square x 10"
thick concrete footings, one near each comer of the building. These should be placed below
the fill 12" into original undisturbed subsoil. The footings should be reinforced with (3) #4
rebars in each directions (3" clearance from soil). A 12" diameter Sonotiibe formed concrete
column can be installed on top of these footings up to grade, this should be reinforced with
(4) vertical #4 bars with a #3 horizontal hoops every 6". The excavated soil must be back
filled and compacted over and around these footings up to grade.
Roof run-off should be directed to a catch basin in the existing conveyance system and tight -
lined to the base of the slope. No drains or concentrated flows should discharge over the
ground or on the slope.
4. A silt fence should be placed on the downhill side of the construction site to attenuate silt -
laden run-off if necessary. Silt fences should be placed around catch basin inlets. Soil that is'
to be removed and reused around the site should be kept away from the top of the slope.
Soils not to be reused. on the site should be hauled off site to an approved location.
5. The vegetation on the steep slopes should be replaced as soon as practical after construction.
Any disturbed soil in the area of the slope should be protected with jute matte or straw and
replanted with native vegetation. After final grading any disturbed or exposed soil needs to
have topsoil spread and compacted and planted witl�vegetation that will retard erosion and
stabilize the upper soil layers.
Grass seed mixture based on soil type, used for erosion control, should be as follows:
Common Name Percent by Wei2ht
Perennial ryegrass 40
Annual ryegrass 20
Red Fescue 40
This should be applied at a hydro -seed rate of 1 LB per 1000 sq. ft. (or 60 LB. per acre); or a
hand seed rate for 2 LB. per 1000 sq. ft. (or 87 LB. per acre). Fertilizer shall be 10-20-20,
applied at the rare of 10 LB. per 1,000 sq. ft. (or 400 LB. per acre).
The following native vegetation are acceptable for permanent plantings on disturbed slopes
and buffers:
Trees*( 3-4' size; plant 6' o.c.)
ShrubsTo be 1-31 size; plant 2 foot
Vine Maple
Kinnick-kinnick
Big leaf maple
Salal
Nobles fir
Snowberry
Grand fir
Vinca Minor
Oregon Grape
Red current
Other native species as recommended by qualified landscape professional knowledgeable in soil
stabilization may also be used.
0
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-------- --------------
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------
00,
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100
I L 71
'w
3nohomish County Area, Washington
TABLE 13—ENGINEERING INDEX PROPERTIES
The symbol < means less than; > I mbans more than. Absence of an entry indicates that data were no t estimated]
117, Soil name and
1
iDepthll USDA texture �i
Class!� !@ l�, 7 z:: g
iments
ercentage
passiH
map symbol
Unified AASHTO
1 > 3
1
sieve
number--
!Liquid
Flas-
i In i
!inches! 4
1 10
40
200
1 limit
ticity
index
T_
P _C-��
I'J 2, 3 ------- --1
,:.Aiderwood
0-7 !Gravelly sandy IGM
loam.
!A-2,
A-4,1 0-5
:55-70
150-65
135-55
120-40
1 20-30 1
NP-5
1 7-351Very gravelly jGM
loam, very
1 A-1
!A-1,
. i
A-2 1 0-10
i
135-55
i
:35-50
i
:25-45
i
110-30
i i
20-30 1
NP-5
gravelly sandy
loam.
35 !Cemented ---------
,'Alderwood ------- 1 0-7 !Gravelly sandy
!A-2,.
A-4,: 0-5
155-70
150-65
135-55
120-40
1 20-30
NP-5
1 loam.
1 A-1
7-35iVery gravelly jGM
1
!A-1,
A-2 1 0-10
:35-55
135-50
125-45
L10-30
1 20-30 1
NP-5
loam, very
gravelly sandy
loam.
1 35 :Cemented ---------
Everett ---------
*, 6:*:
Alderwood--
1 o-6 Gravelly sandy
ism
:A-1, A-2
i 1 loam.
i
1 6-18:Very gravelly
jGP-GM,
GM jA-1
: sandy loam.
i
i
18-60:Very gravelly
:GP
jA-1
coarse sand,
i
i
very gravelly
loamy sand,
extremely
gravelly sand.
0-7 iGravelly sandy
jGM
!A-2, A-4p!
1 loam.
1 A-1
7-351Very gravelly
jGM
:A-1, A-2
1 loam, very
1 gravelly sandy
1 loam.
35 !Cemented ---------
1,
1
0-10 165-85 150-75 '130-50 115-30
5-10 130-60 120-50 i10-30 5-25
5-20 125-50 :15-45 1 5-20 1 0-5
0-5 155-70 1150-�65 135-55 :20-40
0-10 135-55
,35-50 i25-45 1:10-30
15-25 1 NP-5'
15-25 1 NP-5
NP
20-30 NP-5
20-30 1:-NP-5
Jrban lanL
-----------
lellingham
1 0-9 !Silty clay 'loam. 1 ML, OL
1 9-601sil'ty clay, clay, 1 CL CH
1 A-4
1A-7
0
1 100
1 100
195-100180-95 . 1
25 -40
,
silty clay loam.1
0
1 100
195-100195-100185-1001
45-65
----------------
;ellingham
1 0-6 !Mucky silty clay 1ML, CL
1 - 1 loam.
!A-6,
A-7 1 0
1 100
1 100
:85-100180-1001
35-45
Variant
1 6-421Silty clay loam,
1. silty clay. ICL
.:A-7
0
100
1. 100
185-100:80-lbol
40-50
:*42-60!Stratified loamy 1CL-ML,
fine
CL,!A-2,
A-4�i 0
100
1 100
:40-80 120-60 1
20-35
.1 sand to 1 SM-SC,
SCI A-6
1 silty clay loam.1
10, 11 -------- 1 0-8 !Loam ------------- jML
athcart 1 8-35!Loam, sandy loam,!ML, SM
:A-4,
!A-4,
A-5 1 -0
A-5
190-95
185-95
:70-80 :'60-70 1
145-65
35-45
silt loam.
1 0
180-95
180-90
170-85
35-45
135-60!Loam, clay loam IML, SM
'1-4
i 0
180-90
175-85
165 75 140760 1
30-40
.yohemists
--------------
ister
_: 0-9 Fine sandy loam Ism !A-2,
I 9-351:Loamy fine sand, 1SP-SM, SM !A-2,
A-4 1 0
A-3 f 0-20
1 100 190-1-00180-90 136-45
25-30
i 1 sand. i
i
. 195-100190-100170-80
1 5-20 1
i35-60!Fine sand, sand, jSP-SM
jA-3
0-20':95-100160-80
i i
i :
160-70 1 5-10 1
--- I
1 gravelly coarse
sand.
See footnote at end of table.
NP-10
20-40
10-20
20-25
5-15
5-10
5-10
5-10
NP-5
NP
NP
Peter Cho.pelas, PE
Engineering & Design Services
307 N. Olympic Ave, Suite 208
Arlington', WA 98223
C IA. ya
(360) 653-4615- Chopelasandassociates@'gmail.com
AN
Miti2ation Plan
May 17, 2012 per section 23.40.130
�27974
Eric Thuesen
509-9'hAvenue N.
7AL ivl_
Edmonds WA 98020
Ericthuesen@frontier.com
Subject: Slope stabilization measures for plan ck 2011-0775 accessory structure (cabana) at
the above address
Project Description
The building site is a residential building lot of approximately 0.2 acres served by a municipal
sewer and a public water supply, and with an existing residence and garage built on a terrace on a
sloping site. There is a proposed accessory building of 320 SF, with a 360 SF attached deck, a
retaining wall and back fill to enlarge the useful backyard� placed at the top of a steep slope
below the existing residence. The building site is about 160 feet from the toe of the slope, and
about'50 feet in elevation above it.
Goals and Objectives
The project will reduce potential, landslides, stabilize the existing slope, enhance erosion
control on the steep slopes,. and will enhance and add to native vegetation on the hillside.
1. Potential impacts are uncontrolled run-off, erosion and destabilizing the slope d
construction phase. There is new impervious area proposed and the additional loads on
the slopes created by the proposed structures. These will be mitigated by using an
engineered design, construction timing, limiting disturbing the slope to.between May 1
. and October I st, use of a silt fence on the down hill side of the site disturbance, cover any
exposed soils on the slops within 48 hours. Permanent measures will be to direct roof
run-off to the existing stormwater conveyance system, and replanting disturbed soil with
native vegetation suitable for soil stabilizing surface soils.
There are no wetlands, habitat, or shorelines affected by this project, so no habitat
mitigation measures are necessary. However, replanting of the hillside with native
vegetation will enhance the natural environment and provide for improved habitat.
2. Slope stability measurements were done using traditional Singh diagrams. This has
been in use for many decades and has proven to result in safe and stable slopes. This
methodology results is a more stable slopes as indicated by more modem analysis
methods.
R E U
MAY 2 9 2012
BUILDING DEPAR NENT
C!-,Yl CP EDW"
NOS
3. If all recommendations are followed, the likelihood of success are estimated to me 98
percent or greater. The methods proposed have long histories of successful outcomes.
4. Only steep slope areas are affected by this proposal, all mitigation is oriented towards
steep, slope development. All off site impacts will be prevented by following the
recommendations in the Geotech report.
B. Performance Standards. Regular inspections of the site must be made to insure that off
site run-off avoided by containing all surface riun-off on -site during construction. And
that those construction recommendations are followed.
C. Detailed Construction Plans: These are detailed in the Recommendations I section of the
Geotech report. These include:
1. Conventional grading and footings recommendations. And all bearing soil should be
. inspected by the engineer before concrete is poured.
2. Roof Tun -off should be directed to a catch basin in the existing conveyance system and
tight -lined to the base of the slope. No drains or concentrated flows should discharge
over the ground or on the slope.
3. A silt fence should be placed on the downhill side of the construction site to attenuate
silt -laden run-off if necessary. Silt fences should be placed around catch basin inlets.
Soil that is to be removed and reused around the site should be kept away from the top of
the slope. Soilsnot to be reused on the site should be hauled off site to an approved
location. Clearing shall be allowed only from May 1 st to October 1 st, 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.
4. The vegetation on the steep slopes should be replaced as soon as practical after
construction. Any disturbed soil in the area of the slope should be protected with jute
matte or straw and replanted with native vegetation. After fmal grading any disturbed or
exposed soil needs to have topsoil spread and compacted and planted with vegetation
that will retard erosion and stabilize the upper soil layers.
Grass seed mixture based on soil type, used for erosion control, should be as follows:
Common Name Percent by Weight
Perennial ryegrass 40
Annual ryegrass 20
Red Fescue 40
This should be applied at a hydro -seed rate of 1 LB per 1000 sq. ft. (or 60 LB. per acre);
or a hand seed rate for 2 LB. per 1000 sq. ft. (or 87 LB. per acre). Fertilizer, shall be 10-
20-20, applied at the rare of 10 LB. per 1,000 sq. ft. (or 400 LB. per acre).
The following native vegetation are acceptable for permanent plantings on disturbed
slopes and buffers:
0 . 6
trees*( 3-4' size; plant 6' o.c.)
Shrubs*(to be 1-31 size; plant 2 foot
O.C.)
Vine Maple
Kinnick-kinnick
Big leaf maple
Salal
Nobles fir
Snowberry
Grand fir
Vinca'M or
Oregon Grape
Red current
Other native species as recommended by qualified landscape professional knowledgeable in soil
stabilization may also be used.
.D. Monitoring Program. Inspections should be done during the construction at each
phase, and upon completion of the replanting of the exposed soil. Itshould not be
necessary to monitor the health of the vegetation for more than one year after completion.
If the plants are growing, healthy, and providing ground cover, no further action should
be necessary.
E. Contingency Plan. Project modifications may have to be done if unforeseen soil
conditions occur during the soil and excavation inspections, or if unusually wet weather
or soil conditions are encountered.
F. Financial Guarantees. Applicant will post bonds, or a pledge of financial responsibility
(at the director's option) to ensure mitigation, maintenance, and monitoring. [Ord. 3 5 27
§ 2, 2004]. The size of this project is not sufficient to require extensive bonds.
4"�ection 24 T27NIO05E WM
J
Scale 111:201 1*
Prope t
_V Owner/Site Address:
Eric Thuesen 11%. N'
509-9'h Avenue N. N,
Edrnonds WA 98020
Q
Ericthuesen@frontier.corn
1-425-772-9401
Prepared by:
Peter Chopelas PE 'T
307 N. OlYmpic Ave, suite 208- North
A r] -%'17A no
5 � _11� /_ /_ J
(360) 653-4615
Ch6pelasandassociates@gmail.com
. 4D
96 QVM
Legal Description:
SEC. 24 TWP 27 RGE 03 S 11 OFT OF �1/2 SEI/4 SEIA Nw 1/4 EXC E 190FT THOF
LESS W 50FT FOR CITY ST PER AFN 1756635 AKA PAR B OF CITY OF EDM
BLA REC AFN 200416195002
Tax Account Number
27032400220600
Site Plan
Site Plan Notes
I Seasonal Restriction. Clearing shall be allowed only from may I st to October I st of each
year; provided, that the director may extend or shorten the dry season on a case -by -case
basis de -pendinjz on actual weather con'ditions.
2. A silt fenc& should be placed on the d ; ownhi 11 side of the construction site to attenuate
silt-la.den run-off if necessary. Silt fences should'be placed around catch basin inlets.
Soil that is to be removed and reused around the site should be kept away from the top of
the slope. Soils not to be reused on the site should be hauled off site to an approved
location. I
I Roof run-off should be directed to a catch basin in the existing conveyance Sys . tem and
tight -lined to the base of the slol�e. No drains or concentrated flows should discharge
over the ground or on the slope.
4. All vegetation on the slopes shall be le! ft I undisturbed outside of th e con'struction area. The
vegetation on the steep slopes should be replaked as soon as practical after construction.
Any disturbed Soil in the area of the slope should be protected with jute matte or straw
and replanted with native vegetation. After final grading any disturbed or exposed soil
needs to have topsoil spread and compkted and planted with vegetation that will retard
erosion and stabilize the upper soil layers.
Grass seed mixture based on soil type, used for erosion control, should be as follows:
Corn non Name Percent by Wei2ht
Perennial ryegrass 40
Annual ryegra§s 20
Red Fescue 40
This should be applied at a hydro -seed rate of 1 LB per 1000 sq. ft. (or 60 LB.
or a hand seed rate for 2 LB. per 1000 sq. ft. (or 87 LB. per acre). Fertilizer shall be 10-
20-20, applied at the rare of 10 LB. per 1,000 sq. ft. (or 400 LB. per acre).
The following native vegetation are acceptable for -permanent plantings on disturbe . d
slopes and buffers:
Trees*( 34' size; plant 6' o.c- I Shrubs*(to be 1-3' size; plant 2 foot
E�E _L
0
T
O.C.
Vine a le Kinnick-kinnick
V
[Big leaf maple Salal
N L
s f
oble Ir Sno"
s fir Snowberry
Grand fir Vi—c-a M i n o r
Red current
Other native species as recommended by qualified laj�dscape professional knowledgeable in saim-i
stabilization may also be used.
RESUB.,V
MAY 2 9 2012
R;
BIWLI)ING DEPA WENT
CITY OF EDIVIOGS
KA
72 74
M
r'n
-A
M
OV. EDAI, 0
lkst. I
PERMIT # bld20110775
0—ITY OF fEDMONDS — ENGIARING' DIVISION
SPECIAL INSPECTION AND TESTING AGREEMENT
4 %it 6A ip Yx ;Wc 11�XSG&
PROJECT SITE ADDRESS: 509 — 9" Ave N
PROJECT NAME: Thuesen — Cabana and Retaining Wall
SPECIAL INSPECTION AGENCY
DATE: June 6, 2012
*One form must be completed by each Special Inspection Agency or Inspector.
SPECIAL INSPECTIONS REQUIRED: Special inspections are required for this project, as applicable, in
accordance with Title 18 Edmonds Community Development Code (ECDC). When required, the project must
be installed/constructed* per approved plans and specifications. The owner or the registered design prof6ssional
in charge shall employ an independent testing/inspection agency/special inspector to perform required special
inspections. The special inspector shall be a qualified person with competence'for inspecting the specific type
of construction or operation requiring special inspection. The owner, registered professional, contractor and
special inspector/agency shall provide a special inspection report detailing compliance with approved plans and
specifications directly to the Engineering Division.
WORK REQURING SPECIAL INSPECTION: Special inspections will be required for the following
categories of work: FOR SPECIFIC INFORMATION REGARDING REQUIRED SPECIAL INSPECTIONS
SEE THE STATEMENT OF. SPECIAL INSPECTION NOTED AS A CONDITION ON THE BUILDING
PERMIT AND/OR ON THE APPROVED PLANS.
F1 Soil Conditions Prior to Placing Footings and
During Construction STREET FILE
F� Retaining Wall Drainage
BEFORE A PERMIT CAN BE ISSUED: The owner and contractor and special inspector shall complete this
agreement and return to a Permit Coordinator prior to permit issuance.
APPROVAL OF SPECIAL INSPECTORS: Each special inspector shall be approved by the Engineering
Division prior to performing any duties or inspections. The credentials of the specific person performing the
inspection shall be submitted. When applicable, the company performing inspections must be accredited by the
American, Association of State Highway and Transportation Officials (AASHTO) RI 8.
A. Duties and Responsibilities of the Special Inspector
1. OBSERVE WORK
The special inspector shall observe the site work for conformance with the approved (stamped) plans
and specifications. Special inspections are to be performed as needed, to confirm that the work being
completed meets specifications and approved plans.
CADocuments and Settings\mcconnell\Local Settingffemporary Intemet Files\Content.Outlook\52G2LQK3\bld2011O775-
SpeciallnspectionAgreement-ENG,(2).doc Revised 06.06.2012
2. REPORT NONCONFORMING ITEMS
The special inspector shall bring non -conforming items to the immediate attention of the contractor and
engineer of record. The special inspector shall provide a report to the Engineering Division notifying of
any iterdg notTe461vedarydJoT, ho�Ms-tAltFd p�r th6. apq@��d-,�I�hs pdspq
Lns d 11'
Items not constructed per the'apprhedp -an jkcific'dfio s Will Aitjin a review of the plans to
determine what requirements will be needed for the project to meet the necessary stormwater
requirements; such as removal and reconstruction, re -design of the stormwater management system(s),
etc.
Final approval for the project will not occur until installation of all required improvements is complete
and accepted by the Special Inspector and the City.
3. FINAL CONSTRUCTION REPORT
The special inspector or inspection agency shall submit a final signed report or Certificate of
Compliance to the City stating that all items requiring special inspection and testing were fulfilled and
reported. The report shall also include a statement from the inspector stating to the best of his/her
knowledge the project is in conformance with the approved plans, specifications, and approved plan
revisions, if any. Items not in conformance, unresolved items orany discrepancies in inspection
coverage (i.e., missed inspections, periodic inspection when continuous inspections were required, etc.)
shall be specifically addressed in this report.
B. Contractor Responsibilities
1. NOTIFY THE SPECIAL INSPECTOR OF ALL REQUIRED. SPECIAL INSPECTIONS .
It is the duty of the contractor to notify the special inspector when work is ready for special inspection.
Note, the items listed under the statement, of special inspection on the building permit and. as noted on
the approved plans and specifications are required to have special inspections. Adequate notice shall be
provided by the contractor so that the special inspector has time to become familiar with the project. All
work requiring special inspection must be approved prior to concealing or covering said work.
2. PROVIDE ACCESS TO APPROVED PLANS
The contractor is responsible for providing the, special inspector access to approved plans ai the j obsite.
3. RETAIN SPECIAL INSPECTION RECORDS
The contractor is responsible to retain at the jobsite all special inspection records submitted by the
special inspector. These records are to be pt�ovided to the City Engineering inspector upon request and
upon completion of work.
C. City of Edmonds Enineerin2 Division Responsibilities
1. APPROVE SPECIAL INSPECTION
The Engineering Division shall approve all Special Inspectors and special inspection requirements.
2. MONITOR SPECIAL INSPECTIONS AND APPROVE REPORTS
CADocurnents and Settings\mcconnell\Local SettingsUernporary Internet Files\Content.Outlook\52G2LQK3\bld2011O775-
SpecialInspectianAgreement-ENG (2).doc Revised 06.06.2012
Work requiring specialopection and performance of special ioctors shall be monitored by the
Engineering Division Inspector. Engineering Inspector approval must be obtained prior to placement of
concrete or other similar activities in addition to that of the special inspector.
3. FINAL APPROVAL
The Engineering Division may provide final inspection approval after the special inspection report(s)
have been submitted and accepted by the City.
D..Owner Responsibilities
1. The project owner or the en
, gineer or architect of record acting as the owner's agent sl�all iund special
inspection services.
E. 'Engineer or Architect of Record Resposibilifies
1. Prepare Statement of Special Inspections.
2. Review the special inspection reports and provide corrective actionfor work that may not conform to the
approved plans.
Owner name
ACKNOWLEDGEMENTS
I have read and agree to comply with the terms and conditions of this agreement
(please print or type)
Signature Date
General Contractor Company/Owner name
(please print or type)
Signature
Special Inspector/Agency name
(please print or type) .
Date
Signature Date
Engineer of Record name
(please print or type)
Signature Date
Return the original signed agreement to:
City of Edmonds Development Services Department
1215 th Avenue North, City Hall Second Floor
Edmonds, WA 98020
ACCEPTED BY CITY OF EDMONDS ENGINEERING DIVISION:
City Official Signature . Date
Title: I
CADocuments and Settings\mcconneMLocal Settings\Temporary Internet Files\Content.Outlook\52G2LQK3\bld2011O775-,
SpecialInspectionAgreernent-ENG (2).doc Revised 06.06.2012
Mike Clugston
Planning Dept.
City of Edmonds
RECEIVIED
MAY 2 9 202
MaaOMW SMVIMS
RE: PLAN REVIEW ANSWERS TO COMMENTS APRIL 6,2022 FOR PLAN CHECK #2022-0775
ACCESSORY STRUCTURE (CABANA & RETANING WALL) AT 509 e AVE. N.
Dear Mike,
I have provided a revised geotech report, site plan, mitigation plan and structural design for a tie back
retaining wall for the project.
I have also provided the comment answers, revised height elevation and revised site plan (cabana
computed height elevations to the following April 6 comments:
1. STRUCTURAL LOT COVERAGE FOR ALL STRUCUTRES ON THE PARCEL.
Tota I Lot Area
Strucutres Area
Residence
Detached Garage
Proposed Cabana
Total Structure Area
19,786 square feet
2t847.57
418
359
3,624.56 square feet,
Total percentage of Structural Coverage Lot Coverage 18%
2. REVISED ELEVATION DRAWING
New Height Calculations , A) 148
riih�
Z.-
MAY 2 9 2012
BUkDING DEPAR-'MENT
CITY OF EDMONDS
B) 148
C) 144
D) 146 STREET FILE
Total 586 / 4 = 146.5 + ( Max allowable) 15= 161.S Max Roof Ht
8,�D2-o/Z-C;7757�
3. Retaining wall was changed from original proposed after geotech site inspection and test pits -findings
(Geotech Report Chopelas.& Associates).: Existing shallow fills on site required a caba ' na stepped
foundation and retaining wall designed to make slope suitable for permanent buildings and reduce
landslide and increase slope stability. All detail references have been made outlined in ECDC23.40.120.B
and ECDC 23.40. ECDC 23.80
Sincerely,
C, �3
Eric B. Thuesen
I
6 1 1 �)
�1 0 :.
Drainage Report
FOR
Thuesen Custom Homes
(*S-05-09)
at
503 _ 9th Avenue N.
Edmonds, WA 98020
City File # S-05-09
November, 2006
Revised - December, 2006
Revised June, 2007
Revised July, 2007
Prepared for:
Thuesen Custom Homes
17296 Talbot Road
Edmonds, WA 98026
Prepared By: Jerry O'Connell, P.E.
M -- - — Q
E "GIN EERS ISURVELY0118Z
�� M M -
Lovell-Sauerland &Associates, Inc.
19400 33rd Avenue W. Suite 200
Lynnwood, Washington 98036
LSA FILE No: 4288
Section 1: Project Information
Project Name: 98"� Avenue N Short Plat
Project Site Address: 503 9"� AvenueN.
Edmonds, WA 98020
City File Number: S-05-09
Project Engineer: Lovell-Sauerland &Associates, Inc.
19400 33"d Avenue W.' Suite 200
Lynnwood, Washington 98036
Phone: (425) 775-1951
Project Applicant: Thuesen Custom Homes
17296 Talbot Road
Edmonds, WA 98026
Phone: (425) 670-2825
Project Total Area: 1. 03 Acres
Number of Lots: 2 - singlefamily
Soils Data: Alderwood 'C' per Sheet #56 of SCS Soil Survey of
Snohomish County
July Revision Executive Summary
This revision incorporates 4th City review comments as follows:
1. change the reference to the regional detention facility to the shell
creek diversion pipeline.
PALSA Engineering Docs\4200 thru 4299\4288\drainage\4288-jo-rpt2.doc
0, )
SECTION 10
Appendix
P:TSA Engineering Docs\4200 thru 4299\4288\drainage\4288-jo-rpt2.doc