PLN200500038 Staff Report.pdfrnC 1g90
Date:
CITY OF EDMONDS
121 5TH AVENUE NORTH • EDMONDS, WA 98020 • (425) 771-0220 • FAX (425) 771-0221
Website: wwwdedmonds.wa.us
DEVELOPMENT SERVICES DEPARTMENT
Planning • Building • Engineering
Letter of Transmittal
October 18, 2005
To: Mark and Melinda Etscheid
8005 242nd St. SW
Edmonds, WA 98026
Subject: S-05-38
Transmitting Findings, Conclusions, and Decision
For Your Information: X
As you requested:
For your file:
Comment:
Note attachments: X
Cc: Carol West
Lance and Joanne White
Sincerely,
GARY HAAKENSON
MAYOR
Diane Cunningham, Administrative Assistant
• Incorporated August 11, 1890 •
CITY OF EDMODS
121 - 5TH AVENUE NORTH, EDMONDS, WA 98020
PLANNING DIVISION
FINDINGS, CONCLUSIONS, AND DECISION
To: File S-05-38
From:
Date:
October 18, 2005
File: S-05-38
Applicant: Mark and Melinda Etscheid
TABLE OF CONTENTS
Section Page
I.
INTRODUCTION...............................................................................................................2
A. Application.......................................................................................................................................2
B. Decision on Subdivision................................................................................................................... 2
II.
FINDINGS OF FACT AND CONCLUSIONS................................................................... 3
A. Compliance with the Subdivision Ordinance.................................................................................... 3
B. Compliance with the Comprehensive Plan........................................................................................ 5
C. Compliance with the Zoning Code.................................................................................................... 6
D. Compliance with the Flood Plain Management Provisions............................................................... 6
E. Environmental Assessment............................................................................................................... 6
F. Critical Areas Review....................................................................................................................... 6
G. Comments......................................................................................................................................... 7
III.
RECONSIDERATIONS AND APPEALS..........................................................................7
A. Request for Reconsideration............................................................................................................. 7
B. Appeals............................................................................................................................................. 7
C. Time Limits for Reconsideration and Appeals.................................................................................. 7
IV.
LAPSE OF APPROVAL.....................................................................................................7
V.
NOTICE TO COUNTY ASSESSOR..................................................................................7
VI.
APPENDICES..................................................................................................................... 8
VII.
PARTIES OF RECORD......................................................................................................8
Mark & Melinda Etscheid
File No. S-05-38
Page 2 of 8
I. INTRODUCTION
The applicant is proposing to subdivide one lot addressed as 8006 — 2401h Street SW into four lots
(Attachment 1). See the Zoning and Vicinity Map for reference (Attachment 2). The site is located in a
single-family residential (RS-8) zone that allows lots with a minimum area of 8,000 square feet. The
proposed lot layout is shown on the subdivision map (Attachment 3). The existing house has been removed
since the time the application was submitted.
A. Application
1. Applicant: Mark and Melinda Etscheid
2, Site Location: 8006 — 2401h Street SW (see Attachment 2).
3. Re uest: To divide one lot with a total area of 37,140 square feet into four lots in a Single -
Family Residential (RS-8) zone (see Attachment 3).
4. Review Process: Following the Comment Period, Planning Staff makes an administrative
decision.
5. Major Issues:
a. Compliance with Edmonds Community Development Code (ECDC) Section 16.20.030,
site development standards for the RS-8 zone.
b. Compliance with Edmonds Community Development Code (ECDC) Title 18, public
works requirements.
c. Compliance with Edmonds Community Development Code (ECDC) Section 20.75,
subdivision requirements.
d. Compliance with Edmonds Community Development Code (ECDC) Section 20.95,
staff review requirements.
e. Compliance with Edmonds Community Development Code (ECDC) Section 23.80,
geologically hazardous areas requirements.
Note: All code sections referenced in this report can be viewed via the City's website at
www.ci.edmonds.wa.us.
B. Decision on Subdivision
Based upon the Findings of Fact and Conclusions, and Attachments submitted with the application
and during the comment period, the following is the decision of the City of Edmonds Planning
Division:
The subdivision as proposed is APPROVED with the following conditions:
1. Prior to recording, the applicant must complete the following requirements:
a) Civil plans must be approved prior to recording. In completing the civil plans, you
must address the following:
(1) Complete the Engineering Division conditions listed "Required prior to
Recording" on Attachment 4.
b) Make the following revisions to the plat:
(1) Change the street label from "2401h PI. SW" to "2401h St. SW".
(2) If setbacks are to be shown on the final plat, revise the plat as follows:
(a) Adjust the setbacks shown on the plat to reflect the minimum setbacks
required for the RS-8 zone, which are as follows: 25 foot street setback,
7.5 foot side setback, and 15 foot rear setback. Note that Lots 3 and 4
only need to meet the minimum side setback from all property lines
since they are not directly adjacent to a street.
Mark & Melinda Etscheid
File No. S-05-38
Page 3 of 8
(b) Add the following statement to the face of the Plat: "Setbacks shown
are for reference only and vest no right."
(3) Add to the face of the Plat: "Conditions of approval must be met and can be
found in the final approval for the short subdivision located in File S-05-38
in the City of Edmonds Planning Division."
(4) A shared onsite turnaround must be provided per Engineering Requirements
(Attachment 4). Whether this is provided as part of Private Access Tract A
or as an easement, it must be deducted from the lot area without making the
lots smaller than the required 8,000 square feet.
(5) Provide ownership and maintenance information for Private Access Tract A.
(6) Include on the plat all required information, including owner's certification,
hold harmless agreement, and staff's approval block.
c) Make sure all documents to be recorded meet the Snohomish County Auditor's
requirements for recording.
d) Submit copies of the documents to be recorded for the Planning Division and
Engineering Division's approval. Once approved, the applicant must record the
documents with the Snohomish County Auditor's office.
e) Submit an updated copy of the title report (short plat certificate) with the documents
proposed to be recorded.
2. Comply with the recommendations set forth in the Geotechnical Report (see Attachment
5) or any subsequent reports. Note on page 7 of the Geotechnical Report that natural
vegetation on the slope must be left intact.
3. After recording the plat, the applicant must complete the following:
a) Provide the City Planning Division with two copies of the recorded plat, with the
recording number written on them. The City will not consider the subdivision to
have been completed until this is done.
b) Complete the Engineering Division conditions listed "Required with Building
Permit" on Attachment 4.
A. Compliance with the Subdivision Ordinance
1. Introduction
Setting:
The subject property at 8006 — 2401h Street SW is located in the Single -Family Residential
(RS-8) zone (Attachment 2). The immediately surrounding properties are also zoned RS-8
and are developed with single-family residences. A cluster of properties approximately 200
feet west of the subject property are zoned RM-3 and RM-2.4, while the properties west of
those are zoned CG.
b. Topography and Vegetation:
The lot is generally flat where the existing house had been located, but it is rather steeply
sloped throughout much of the remainder of the site. In general, the site slopes downward
from the northwest portion to the southeast portion. During review and inspection of the
subject site, it was found that the site contains a slope that is steep enough to be considered a
Landslide Hazard Area.
Any landscaping that was present in the immediate vicinity of the existing house, which has
been removed since the application was submitted, has also been removed. Vegetation on the
undeveloped portion of the site is natural and consists mostly of large trees with sparse to
Mark & Melinda Etscheid
File No. S-05-38
Page 4 of 8
moderate undergrowth. The trees indicated on the site plan include pine, fir, alder, cedar,
maple, and deciduous trees.
C. Lot Lam:
The proposed lot layout is shown on the subdivision map (Attachment 3). The existing house
has been removed. Four lots will be created. Proposed Lots 1 and 2 will front on 2401h Street
SW and proposed Lots 3 and 4 will be located south of proposed Lots 1 and 2. All proposed
lots will be accessed by a private access tract off of 240`h Street SW.
2. Environmental Resources
The subdivision chapter, ECDC 20.75.085, states that a proposed subdivision should be
designed to minimize significant adverse impacts where environmental resources exist (such
as trees, streams, ravines, or wildlife habitats). The site contains pine, fir, alder, cedar,
maple, and deciduous trees. Most of the large trees on the site are located on proposed Lots
3 and 4. The minimum required setbacks and the maximum lot coverage permitted within the
RS-8 zone will enable the retention of some of the existing trees. There are no other apparent
environmental resources on this site.
b. The proposal minimizes grading because one driveway will be shared by all four lots.
During review and inspection of the subject site, it was found that the site contains a slope
that is steep enough to be considered a Landslide Hazard Area. Due to this fact, the applicant
was required to submit a report by a licensed Geotechnical Engineer with the application.
The "Subsurface Exploration, Geologic Hazard, and Geotechnical Engineering Report" was
prepared by Associated Earth Sciences, Inc. and concluded that the subject property is
suitable for the proposed subdivision (see Attachment 5). The report included
recommendations in order to minimize the risks associated with future development on the
subject property. The preliminary drainage plan submitted with the application shows that
the degree of the steep slope will be reduced during development of the subject property. No
other hazardous conditions exist on this site.
A drainage plan must be submitted to the Engineering Department when a building permit is
applied for on this site. Any proposed development on the site should be designed to
minimize off -site impacts on drainage. All new impervious surfaces must be connected to a
detention system.
Views in this location are local and should not be negatively impacted by the proposal.
Lot and Street Layout
a. This criteria requires staff to find that the proposed subdivision is consistent with the
dimensional requirements of the zoning ordinance and that the lots would ultimately be
buildable. Based on a review of the project and the analysis in this section, staff agrees that a
four lot short -plat is a reasonable use of the property.
b. Lot sizes and dimensions:
Lot Area:
Required
Lot Area
Proposed
Gross s . ft
Proposed
Nets . ft
Lot 1
8,000
8,020
8,020
Lot 2
8,000
8,022
8,022
Lot 3
8,000
9,171
9,171
Lot 4
8,000
9,895
9,895
Lot Width:
The required lot width in the RS-8 zone is 70 feet. The proposed lots meet this requirement.
Mark & Melinda Etscheid
File No. S-05-38
Page 5 of 8
4. Setbacks and Lot Coverage
a. In order to approve a subdivision, the proposal must meet all requirements of the zoning
ordinance, or a modification must be approved. Based on the development standards for the
RS-8 zone, setbacks for the lots should be as follows:
Lot 1: Street Setback (25 feet):
Side Setbacks (7.5 feet):
Rear Setback (15 feet):
Lot 2: Street Setback (25 feet):
Side Setbacks (7.5 feet):
Rear Setback (15 feet):
Lot 3: Side Setbacks (7.5 feet):
Lot 4: Side Setbacks (7.5 feet):
From the north property line (2401h St. SW).
From the east and west property lines.
From the south property line.
From the north property line (2401h St. SW).
From the east and west property lines.
From the south property line.
From all property lines.
From all property lines.
b. Existing Structures / Encroachments: There was an existing house on the subject property at
the time the application was submitted, but it has since been removed. There are no
structures currently on the property.
C. Corner Lots: None of the lots are considered corner lots.
d. Flag or Interior lot determination: Lots 3 and 4 are flag lots.
e. Lot Coverage of Existing Buildings on Proposed Lots:
1.) 35% maximum lot coverage is allowed in the RS-8 zone.
2.) The existing house and attached carport have been removed. Therefore, all proposed
lots currently have a zero percent lot coverage. Any future buildings or structures on
the proposed lots will be allowed to cover no more than 35% of each lot.
5. Dedications
a. A 10-foot street dedication is required to the City of Edmonds, per City Engineer's
Requirements (Attachment 4).
6. Improvements
a. See Engineering Requirements (Attachment 4).
7. Flood Plain Management
a. This project is not in a FEMA designated Flood Plain,
B. Compliance with the Comprehensive Plan
1. Comprehensive Plan Goals and Policies:
The Comprehensive Plan has the following stated goals and policies for Residential Development
that apply to this project.
B. Goal. High quality residential development which is appropriate to the diverse
lifestyle of Edmonds residents should be maintained and promoted. The options
available to the City to influence the quality of housing for all citizens should be
Mark & Melinda Etscheid
File No. S-05-38
Page 6 of 8
approached realistically in balancing economic and aesthetic consideration, in
accordance with the following policies:
B.1. Encourage those building custom homes to design and construct homes
with architectural lines which enable them to harmonize with the
surroundings, adding to the community identity and desirability.
B.3. Minimize encroachment on view of existing homes by new construction or
additions to existing structures.
B.4. Support retention and rehabilitation of older housing within Edmonds
whenever it is economically feasible.
B.5. Protect residential areas from incompatible land uses through the careful
control of other types of development and expansion based upon the
following principles:
B.5.d. Private property must be protected from adverse environmental
impacts of development including noise, drainage, traffic, slides,
etc.
B.6. Require that new residential development be compatible with the natural
constraints of slopes, soils, geology, vegetation and drainage.
2. Compliance with the Residential Development goals and policies: This proposal will make way
for four new homes. Views from surrounding properties are local and should not be significantly
impacted by the proposal. The proposal accounts for the existing steep slope and will reduce the
degree of this slope. The overall proposal should not cause any adverse impacts and appears to
be consistent with the residential development goals and policies.
C. Compliance with the Zoning Code
The proposed subdivision complies with the provisions of the Zoning Code. See sections II.A.3
and II.AA of this document.
D. Compliance with the Flood Plain Management Provisions
1. The proposed project is not in a Flood Plain.
E. Environmental Assessment
1. Is this site within a shoreline area (within 200 feet of the ordinary high water mark of the Puget
Sound)? No.
2. Is an Environmental Checklist Required for this application? No. If more than 500 cubic yards
of grading will be required, an Environmental Checklist is required. At this point in time, the
total amount of grading for the subdivision improvements is not anticipated to exceed 500 cubic
yards. If through the review of the civil plans, it is determined that more than 500 cubic yards of
grading will be required, the City will require an Environmental Checklist to be submitted and
will issue an Environmental Determination.
F. Critical Areas Review
1. Critical Areas Review number: CA-2005-0037.
Results of Critical Areas Reviews: During review and inspection of the subject site, it was
found that the site contains a slope that is steep enough to be considered a Landslide Hazard
Area. This slope is defined as a critical area by Section 23.40 of the Edmonds Community
Development Code (ECDC). Therefore, the applicant was required to submit a report by a
licensed Geotechnical Engineer with the application (see Attachment 5). This report concluded
that the subject property is suitable for the proposed subdivision. The report also included
Mark & Melinda Etscheid
File No. S-05-38
Page 7 of 8
recommendations to minimize the risks associated with future development of the subject
property. The recommendations of the report should be followed.
G. Comments
No public comment letters were received during the review of the proposal; however, one party of
record request was made by Lance and Joanne White.
The following is a summary of the deadlines and procedures for filing reconsiderations and appeals. Any
person wishing to file or respond to a recommendation or appeal should contact the Planning Department
for further procedural information.
A. Request for Reconsideration
Section 20.100.010.E allows for City staff to reconsider their decision if a written request is filed
within ten (10) working days of the posting of the notice required by this section. The
reconsideration request must cite specific references to the findings and/or the criteria contained in
the ordinances governing the type of application being reviewed.
B. Appeals
Section 20.105.040 and 20.105.020 describes how appeals of a staff decision shall be made. The
appeal shall be made in writing, and shall include the decision being appealed along with the name
of the project and the date of the decision, the name of the individual or group appealing the
decision, their interest in the matter, and reasons why the appellant believes the decision to be
wrong. The appeal must be fled with the Community Development Director within fourteen (14)
calendar days after the date of the decision being appealed.
C. Time Limits for Reconsideration and Appeals
The time limits for Reconsiderations and Appeals run concurrently. If a request for a
reconsideration is fled before the time limit for fling an appeal has expired, the time "clock" for
fling an appeal is stopped until a decision on the reconsideration request is completed. Once the
staff has issued his/her decision on the reconsideration request, the time clock for fling an appeal
continued from the point it was stopped. For example, if a request is filed on day 5 of the appeal
period, an individual would have 9 more days in which to file an appeal after the staff issues their
decision on the reconsideration request.
Section 20.075.100 states, "Approval of a preliminary plat or preliminary short plat shall expire and have
no further validity at the end of five years, unless the applicant has acquired final plat or final short plat
approval within the five-year period."
The property owner may, as a result of the decision rendered by the staff, request a change in the valuation
of the property by the Snohomish County Assessor's Office.
Mark & Melinda Etscheid
File No. S-05-38
Page 8 of 8
VI. APPENDICES
Attachments:
1. Application
2. Vicinity / Zoning Map
3. Subdivision Map
4. Engineering Requirements
5. Excerpt from the "Subsurface Exploration, Geologic Hazard, and Geotechnical Engineering Report' by
Associated Earth Sciences, Inc. dated May 20, 2005.
Engineering Department
Planning Department
Mark and Melinda Etscheid
8005 — 242"d Street SW
Edmonds, WA 98026
Carol West
2120 Hewitt Avenue
Everett, WA 98201
Lance and Joanne White
24024 — 79`h Place W
Edmonds, WA 98020
city of edmonds
land use application
0 ARCHITECTURAL DESIGN REVIEW
0 COMPREHENSIVE PLAN AMENDMENT
0 CONDITIONAL USE PERMIT. t FILE # c�'05'-rb ZONE
0 HOME OCCUPATION DATE �s- t=�� REC'D BY S/.O-
0 FORMAL SUBDIVISION �� �U FEEA I2fr� r RECEIPT # _ Z5-9 79
0 SHORT SUBDIVISION C Q 1 3 �i
0 LOT LINE ADJUSTMENT 3`-te -- 11 5 HEARING DATE
0 PLANNED RESIDENTIAL DEVELOPMENT a 0 HE YSXAFF 0 PB 0 ADB 0 CC
0 OFFICIAL STREET MAP AMENDMENT
0 STREET VACATION
0 REZONE
0 SHORELINE PERMIT
0 VARIANCE / REASONABLE USE EXCEPTION
0 OTHER:
PROPERTY ADDRESS OR LOCATION--?,(—) C) 2.q � � S� e o %gym
PROJECT NAME (IF APPLICABLE) rC I S Ll�i e y 1 O'f
PROPERTY OWNER _M J/k i o 1 el lyxlol, ��S -" � kPHONE #
ADDRESS 0905 `TZ��S} cj(/�J
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The undersigned applicant, and his/her/its heirs, and assigns, in consideration on the processing of the application
agrees to release, indemnify, defend and hold the City of Edmonds harmless from any and all damages, including
reasonable attorney's fees, arising from any action or infraction based in whole or part upon false, misleading,
inaccurate or incomplete information furnished by the applicant, his/her/its agents or employees.
By my signature, I certify that the information and exhibits herewith submitted are true and correct to the best of my
knowledge and that I am authorized to fi this application on the behalf of the owner as listed below.
SIGNATURE OF APPLICANT/AGENT / _- DATE
Property Owner's Authorization
By my signature, I certify that I have authorized the above Applicant/Agent to apply for the subject land use
application, and grant my permission for the public officials and the staff of the City of Edmonds to enter the subject
property for the purposes
offiinsp ton nd posting attendant to this apph
SIGNATURE OF OWNER vG '�� DATE �S US—
r
This application f nn was revised on 1/27/00. To verify whether it is still current, call (425) 771-0220.
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'ECORDER'S CERTIFICATE:
FILED FOR RECORD BY 7K WEST
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Short Subdivision
The West Group, Inc. for
`�;,i/' Pmfl lonm Lend Sur4ay" do Plonne Mark & Melinda Etscheid
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2005-19
SlaT/OF.
CITY OF EDMONDS
ENGINEERING REQUIREMENTS FOR SHORT PLATS
Name: ETSCHIED File No.: S-05-38
Approved by: l°1�� `' �`-Vicinity: 8005 240TH ST SW
Engineering Program Manager elate
Req'd
Req'd w/bldg.
Bond posted
Complete
prior to
Permit
recording
1. Rights -of -way for public streets:
10.0' Street dedication required to the City of Edmonds
X
2. Easements (City utilities, private access, other utilities):
Provide all easements as needed.
X
3. Street improvements (ACP with curb and gutter):
Provide 1 common shared access road for all lots. Access road
X
shall be paved a minimum of 16.0' wide plus 18" asphalt
thickened edge. Concrete extruded curb or curb and gutter may
also be used.
Access for the above lots shall be off 240d St SW
X
Construct 18" concrete curb and gutter along the property
X
frontages 93`d PL W.
Widen 240`h St SW to 11.0' from painted centerline along
X
property frontage.
4. Street turnaround:
Provide a shared on -site turn around to City Stds.
X
5. Sidewalks and/or walkways:.
Construct 5' wide concrete sidewalk along property frontage on
X
240' St SW.
6. Street lights:
N/A
X
7. Planting strip:
N/A
X
8. Water system improvements (pipelines, fire hydrants, etc)
OVWSD
Provide service to each lot.
X
Connect to public water system.
X
X
9. Sanitary sewer system improvements (pipelines, pump
stations etc) OVWSD
Provide new service to each lot
X
Connect to public sewers stem
X
X
10. Storm sewer system improvements (pipelines, DOE,
fisheries, etc.):
Provide storm sewer service to all proposed lots.
X
Construct storm detention system sized to provide adequate
X
capacity for proposed single family dwellings and access
improvements in accordance with ECDC 18.30.
Connect to Public Storms stem
X
11. On -site drainage (plan per Ord. 3013):
Connect all new impervious surfaces to detentions stem.
X
X
12. Underground wiring (per Ord. 1387):
Required for all new services
X
X
13. Excavation and grading (per UBC, Chapter 70 :
Submit a grading plan as part of engineered site plan.
X
X
V:\dww\sp\05-38 etscheid plt.doc Attachment
Req'd prior to
Req'd w/bldg.
Bond
Complete
recordin
Permit
posted
14. Signage (per City Engineer):
All signs shall be vinyl letters and to City Stds. No silk screen
X
signs will be permitted
Install "Access Road Ends"
X
Install high intensity sign at the entrance
X
Provide fire and aid address si na e
X
15. Survey monumentation (per Ord., Section 12.10.120):
N/A
X
16. As -built drawings (per City Engineer):
Required for all utility construction.
X
X
17. Other requirements:
a) Plat showing lots, easements, legals, survey information
X
X
b) Legal documents for each lot
X
c) Field stake lot corners (by professional engineer)
X
d) Clustered mailbox location per Postmaster
X
e Maintenance agreements
X
18. Engineering fees:
a) Storm drainage connection charge for plat road ( $462.24 )
X
b) Storm drainage connection charge per lot ($ 428 )
X
c) Sewer connection fee per SFR OVSWD ( $ )
X
d) Sewer connection charge/LID fees to be paid in full.
X
e) Water connection fee per SFR (based on meter size)
X
d) Plat inspection fee: 2.2% of improvement costs $
X
e) Plan review fee: ($ 860.)
X
Traffic mitigation: total for both short plats $ 3362.88)
X
4-- tom® Y,—
ENGINEERING PROGRAM MANAGER, CITY OF EDMONDS DATE
lwiEnganeewitrg requirements have been completed and the subdivision can be recorder.
Authorized for recording by:
V:\dvrw\sp\05-38 etscheid plt.doc
Subsurface Exploration, Geologic Hazard, and
Etscheid Short Plat Geotechnical Engineering Report
Edmonds, Washington Project and Site Conditions
I. PROJECT AND SITE CONDITIONS
1.0 INTRODUCTION
This report presents the results of our subsurface exploration, geologic hazard, and
geotechnical engineering study for the proposed short plat. Our recommendations are
preliminary in that project plans were still under development at the time of our subsurface
exploration and preparation of this report. The site location is shown on the Vicinity Map,
Figure 1. The existing site features and approximate locations of the explorations
accomplished for this study are presented on the Site and Exploration Plan, Figure 2. In the
event that any changes in the nature, design, or locations of the proposed improvements are
planned, the conclusions and recommendations contained in this report should be reviewed and
modified, or verified, as necessary.
1.1 Purpose and Scope
The purpose of this study was to provide subsurface data to be utilized in the design of the
project. Our study included a review of selected geologic literature, excavating exploration
pits, and performing geologic studies to assess the type, thickness, distribution, and physical
properties of the subsurface sediments and shallow ground water. Geotechnical engineering
studies were completed to determine the type of suitable foundation, allowable foundation soil
bearing pressure, anticipated foundation and floor settlement, floor support recommendations,
and pavement and drainage design considerations. This report summarizes our current
fieldwork and offers development recommendations based on our present understanding of the
project. We recommend that we be allowed to review project plans prior to construction to
verify that our geotechnical recommendations have been correctly interpreted and incorporated
into the design. Additional exploration or design modifications/review may be required to
finalize project documentation.
1.2 Authorization
We were verbally authorized to proceed with this study. This report has been prepared for the
exclusive use of Ms. Melinda Etscheid and her agents for specific application to this project.
Within the limitations of scope, schedule, and budget, our services have been performed in
accordance with generally accepted geotechnical engineering and engineering geology practices
in effect in this area at the time our report was prepared. No other warranty, express or
implied, is made.
Attachment
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Edmonds, Washington Project and Site Conditions
2.0 PROJECT AND SITE DESCRIPTION
This report was completed with an understanding of the project based on our discussions with
Ms. Etscheid and the Short Subdivision Plan dated February 15, 2005 prepared by The West
Group, Inc. Based on information provided to us, it is our understanding that project plans
include subdivision of an existing residential property into four separate parcels for single-
family residential development. Site development will include construction of homes, a private
access road, and associated utilities.
The site is located at 8006 240t1' Street SW in Edmonds, Washington (Figure 1). The site is
bounded on the north by 240`h Street SW. Private property surrounds the site to the south,
east, and west. A single-family residence currently occupies the north central portion of the
site. The undeveloped portion of the site is wooded with sparse to moderate undergrowth. In
general, the site slopes from the northwest toward the southeast. Topographic fall across the
site is approximately 30 feet with slope gradients ranging from 5:1 to 2:1 (Horizontal:
Vertical).
3.0 SUBSURFACE EXPLORATION
Our field study included excavating six exploration pits to gain subsurface information about
the site. The various types of sediments, as well as the depths where characteristics of the
sediments changed, are indicated on the exploration pit logs presented in the Appendix. The
depths indicated on the logs where conditions changed may represent gradational variations
between sediment types. Our explorations were approximately located in the field by
estimation and measurement from known site features as depicted on the plan provided to us.
The conclusions and recommendations presented in this report are based on the six exploration
pits completed for this study. The number, locations, and depths of the explorations were
completed within site and budgetary constraints. Because of the nature of exploratory work
below ground, extrapolation of subsurface conditions between field explorations is necessary.
It should be noted that differing subsurface conditions may sometimes be present due to the
random nature of deposition and the alteration of topography by past grading and/or filling.
The nature and extent of any variations between the field explorations may not become fully
evident until construction. If variations are observed at that time, it may be necessary to re-
evaluate specific recommendations in this report and make appropriate changes.
3.1 Exploration Pits
The exploration pits were excavated with a rubber -track excavator. The pits permitted direct,
visual observation of subsurface conditions. Materials encountered in the exploration pits were
studied and classified in the field by a geologist from our firm. The exploration pits were
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Edmonds, Washington Project and Site Conditions
backfilled immediately after examination and logging. Selected samples were then transported
to our laboratory for further visual classification and testing, as necessary.
4.0 SUBSURFACE CONDITIONS
Subsurface conditions at the project site were inferred from the field explorations accomplished
for this study, visual reconnaissance of the site, and review of selected geologic literature. As
shown on the field logs, the exploration pits generally encountered natural glacial sediments
overlain in places by topsoil/forest duff and/or fill. The following section presents more
detailed subsurface information organized from the shallowest (youngest) to the deepest
(oldest) sediment types.
4.1 Stratigraphy
Fill
The site appears to have been partially graded during previous site development. Previous
grading appears to have resulted in man -placed fill across the northwest portion of the site. In
general, we assume that existing fill is present within the northwest portion of the site and in
the vicinity of the existing foundation and buried utilities.
Soil interpreted to be man -placed fill was encountered in four of the exploration pits (EP-1,
EP-2, EP-4, and EP-6) excavated at the site. The fill, consisting of a very loose to loose
mixture of silt and sand with variable amounts of debris/trash and root matter in a generally
moist to very moist condition, ranged in depth from approximately 1 to 7 feet below existing
ground surface. Because the existing fill was observed to be in a generally loose condition and
due to the relatively high debris/trash and organic content, we recommend that the existing fill
not be used for support of new foundations, floors, or paving. The fill soil may be suitable for
reuse as structural fill provided debris and organics can effectively be removed and the soil is
moisture -conditioned, as necessary, and compacted as detailed in the Structural Fill section of
this report.
Forest Duff/Topsoil
A surficial layer of organic topsoil and/or forest duff was encountered at most of the
exploration pit locations except exploration pits EP-2 and EP-6. This organic layer was
commonly about 6 inches thick. Due to their high organic content, these sediments are not
considered suitable for foundation, slab -on -grade floor, or pavement support, or for use in a
structural fill.
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Edmonds, Washington Project and Site Conditions
Vashon Lodgement Till
Sediments consisting of dense to very dense, silty sand with gravel were encountered at all
exploration pit locations. We interpret these sediments to be representative of Vashon
lodgement till. The Vashon lodgement till was deposited directly from basal, debris -laden
glacial ice during the Vashon Stade of the Fraser Glaciation. The high relative density
characteristic of lodgement till is due to its consolidation by the massive weight of the glacial
ice from which it was deposited. The upper portion of the till was weathered to a loose to
medium dense state to depths of approximately 2 feet (minimum) to 8.75 feet (maximum)
below ground surface in exploration pits EP-2 and EP-6, respectively. The unweathered
lodgement till sediments extended beyond the maximum depths explored of approximately 9
feet. The weathered and unweathered lodgement till soils are suitable for support of structures
and pavements if properly prepared according to the recommendations presented in this report.
4.2 Hydrology
No ground water seepage was observed in the exploration pits. It should be noted that
fluctuations in the level of the ground water may occur due to the time of the year, variations
in the amount of precipitation, on- and off -site land usage, and other factors.
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Edmonds, Washington Geologic Hazards and Mitigations
IL GEOLOGIC HAZARDS AND MITIGATIONS
The following discussion of potential geologic hazards is based on the geologic, slope, and
shallow ground water conditions as observed and discussed herein.
5.0 SEISMIC HAZARDS AND RECOMMENDED MITIGATION
Earthquakes occur in the Puget Lowland with great regularity. The vast majority of these
events are small and are usually not felt by people. However, large earthquakes do occur as
evidenced by the 1949, 7.2-magnitude event; the 2001, 6.8-magnitude event; and the 1965,
6.5-magnitude event. The 1949 earthquake appears to have been the largest in this region
during recorded history and was centered in the Olympia area. Evaluation of earthquake
return rates indicates that an earthquake of the magnitude between 5.5 and 6.0 is likely every
25 to 40 years in the Puget Sound basin.
Generally, there are four types of potential geologic hazards associated with large seismic
events: 1) surficial ground rupture; 2) seismically induced landslides; 3) liquefaction; and 4)
ground motion. The potential for each of these hazards to adversely impact the proposed
project is discussed below.
5.1 Surficial Ground Rupture
The nearest known fault trace to the project is the South Whidbey Island -Lake Alice Fault.
Recent studies by the U.S. Geological Survey (USGS) suggest that a trace of the northwest -
southeast trending thrust fault zone may project about 3 miles north of the project site. The
recognition of this fault is relatively new and data pertaining to it are limited with the studies
still ongoing. According to the USGS studies, the recurrence interval of movement along this
fault system is still unknown, although it is hypothesized to be in excess of several thousand
years. Due to the suspected long recurrence interval, the potential for surficial ground rupture
at the subject property is considered to be low during the expected life of the structures.
5.2 Landslides
According to the City of Edmonds Municipal Code, Title 23, Section 23.80.020(B), a landslide
hazard area is defined to include: 1) areas of ancient or historic landsliding, 2) any area with a
slope of 40 percent or steeper over a vertical relief of 10 feet or more, 3) potentially unstable
areas as a result of rapid stream incision or stream bank erosion and, 4) areas located on
alluvial fans. Most the subject site does not meet these criteria and is not classified as a
landslide hazard area. A small area of the site located south of the existing house has a slope
inclination of 50 to 66 percent over a vertical height of 10 to 12 feet (Figure 2). This slope is
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s, Washington Geologic Hazards and Mitigations
an artificially constructed slope that consists of fill to create a flat building pad for the existing
house that was moved onto its present location.
The potential for static/seismically induced landsliding over the majority of the site is
considered to be low due to the lack of extensive steep slopes on the project site. Grade
differential across the site is anticipated to be supported by structural retaining walls and steep
slope fill areas are anticipated to be regraded during site development. Therefore it is our
opinion that the risk of static (weather -induced) and/or seismically induced landsliding is low at
the site.
5.3 Liquefaction
The encountered stratigraphy has a low potential for liquefaction due to the lack of adverse
ground water conditions and high strength of the glacial soils. No mitigation of liquefaction
hazards at this site is considered to be warranted.
5.4 Ground Motion
Guidelines presented in the 2003 International Building Code (IBC) Section 1615 should be
used for design related to seismic aspects of the project. Information presented in IBC Figure
1615(1) indicates a mapped spectral acceleration for short periods (0.2 seconds) of S, = 1.25.
Information presented in Figure 1615(2) indicates a mapped spectral acceleration for a 1
second period of Si = 0.42. Based on the results of subsurface exploration and on an
estimation of soil properties at depth utilizing available geologic data, site soils are classified as
Site Class "C" in conformance with Table 1615.1.1. Using the mapped spectral acceleration
in conjunction with the identified site class, information presented in Tables 1615.1.2(l) and
1615.1.2(2) indicates site coefficients Fa = 1.0 and Fv = 1.4 is recommended for use in site
seismic design and analysis.
EROSION HAZARDS AND MITIGATION
According to the Edmonds Municipal Code, Title 23, Section 23.80.020(A), an erosion hazard
area is: 1) one underlain by Alderwood soils with 15 to 25 percent slopes, Alderwood/Everett
soils with 25 to 70 percent slopes, or Everett soils with 15 to 25 percent slopes; or 2) a site
with slopes greater than 15 percent with interbedded permeable and impermeable soils and
ground water seepage; or 3) areas that exhibit significant ground water seepage regardless of
slope. According to the Soil Survey of Snohomish County (United States Department of
Agriculture [USDA] 1983), the site is underlain by Alderwood Urban Complex soils with 8 to
15 percent slopes. The subject site does not meet the criteria for an erosion hazard area.
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Edmonds, Washington Geologic Hazards and Mitigations
To reduce the potential for off -site sediment transport, we would recommend the following:
1. Control of surface discharge during and following development should be performed in
order to reduce the hazard of erosion. Care should be taken to ensure that surface
runoff and domestic discharge will not be directed onto the sloping areas. All devices
used to collect surface discharge should be directed into a tightlined system that
discharges away from slope areas. Uncontrolled discharge on the slope areas may
promote erosion and slope movement.
2. To reduce the amount of sediment transport during construction, a silt fence should be
placed along the lower perimeter of the site prior to commencement of site
development.
3. Construction should proceed during the drier periods of the year and disturbed areas
should be revegetated as soon as possible.
4. Soils that are to be reused around the site should be stored in such a manner as to
reduce erosion from the stockpile. Protective measures may include, but are not
necessarily limited to, covering with plastic sheeting, the use of low stockpiles in flat
areas, or the use of straw bales/silt fences around pile perimeters.
5. In order to reduce potential erosion hazards, natural vegetation on the slope must be left
intact. Other areas stripped of natural vegetation during construction should be
replanted as soon as possible, or otherwise protected.
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Subsurface--,ploration, Geologic Hazard, and
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Edmonds, Washington Design Recommendations
III. DESIGN RECOMMENDATIONS
7.0 INTRODUCTION
Our exploration indicates that, from a geotechnical standpoint, the parcel is suitable for the
proposed subdivision and future development provided the risks discussed are accepted and the
recommendations contained herein are properly followed. With the exception of the fill area
within the northwest portion of the site, the bearing stratum is relatively shallow and spread
footing foundations may be utilized. It is anticipated that fill within the northwest portion of
the site will be removed and replaced as compacted fill during site development.
Recommendations for deep foundations extending through fill and into underlying stratum can
be presented, if requested. We understand that the distribution of foundation loads of the
wood -frame residential buildings will be typical; no concentrated loads are anticipated.
Consequently, the native, medium dense to very dense lodgement till, or structural fill bearing
on these soils, are capable of providing suitable building and pavement support. The
conclusions and recommendations presented in this report are offered as a means to identify
and reduce risks associated with steep slopes, erosion, and seismic hazards.
8.0 SITE PREPARATION
Old foundations that may be on the site and that are under building areas or not part of future
plans should be removed. Any buried utilities should be removed or relocated if they are
under building areas. The resulting depressions should be backfilled with structural fill as
discussed under the Structural Fill section.
Site preparation of planned building and road areas should include removal of all trees, brush,
debris, and any other deleterious material. Additionally, the upper organic topsoil should be
removed and the remaining roots grubbed. Areas where loose surficial soils exist due to
grubbing operations should be considered as fill to the depth of disturbance and treated as
subsequently recommended for structural fill placement.
Loose native soil and fill should be stripped down to the underlying medium dense to dense till
soils below the root zone. Since the density of the soil can be variable, random soft pockets
may exist, and the depth and extent of stripping can best be determined in the field by the
geotechnical engineer or engineering geologist. We recommend that road areas be proof -
rolled with a loaded dump truck to identify any soft spots; soft areas should be overexcavated
and backfilled with structural fill.
In our opinion, stable construction slopes should be the responsibility of the contractor and
should be determined during construction. For estimating purposes, we anticipate that
temporary, unsupported cut slopes in the unsaturated loose fill can be made at a maximum
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Edmonds, Washington Design Recommendations
slope of 1.5H:IV; temporary cuts in unsaturated weathered and unweathered till can be made
at a maximum slope of MAN. If ground water seepage is present, less steep slope cuts or
shoring may be required. As is typical with earthwork operations, some sloughing and
raveling may occur and cut slopes may have to be adjusted in the field. In addition,
WISHA/OSHA regulations should be followed at all times.
The portions of the site underlain by till contain a high percentage of fine-grained material that
makes them moisture -sensitive and subject to disturbance when wet. The contractor must use
care during site preparation and excavation operations in these areas so that the underlying
soils are not softened. If disturbance occurs, the softened soils should be removed and the area
brought to grade with structural fill. Consideration should be given to protecting access and
staging areas with an appropriate section of crushed rock or quarry spalls.
9.0 STRUCTURAL FILL
It is possible that structural fill will be necessary to establish desired grades. All references to
structural fill in this report refer to subgrade preparation, fill type, placement, and compaction
of materials as discussed in this section. If a percentage of compaction is specified under
another section of this report, the value given in that section should be used.
After stripping, planned excavation, and any required overexcavation have been performed to
the satisfaction of the geotechnical engineer/engineering geologist, the upper 12 inches of
exposed ground should be recompacted to a firm and unyielding condition as determined by the
geotechnical engineer or his representative. If the subgrade contains too much moisture,
adequate recompaction may be difficult or impossible to obtain and should probably not be
attempted. In lieu of recompaction, the area to receive fill should be blanketed with washed
rock or quarry spalls to act as a capillary break between the new fill and the wet subgrade.
Where the exposed ground remains soft and further overexcavation is impractical, placement
of an engineering stabilization fabric may be necessary to prevent contamination of the free -
draining layer by silt migration from below.
After the recompacted, exposed ground is tested and approved, or a free -draining rock course
is laid, structural fill may be placed to attain desired grades. Structural fill is defined as non -
organic soil, acceptable to the geotechnical engineer, placed in maximum 8-inch loose lifts
with each lift being compacted to at least 95 percent of the modified Proctor maximum density
using ASTM:D 1557 as the standard. In the case of roadway and utility trench filling, the
backfill should be placed and compacted in accordance with current local or county codes and
standards. The top of the compacted fill should extend horizontally outward a minimum
distance of 3 feet beyond the location of the perimeter footings or roadway edge before sloping
down at an angle of 2H:1V.
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ds, Washington Design Recommendations
The contractor should note that Associated Earth Sciences, Inc. (AESI) must evaluate any
proposed fill soils prior to their use in fills. This would require that we have a sample of the
material 72 hours in advance of filling activities to perform a Proctor test and determine its
field compaction standard. Soils in which the amount of fine-grained material (smaller than the
No. 200 sieve) is greater than approximately 5 percent (measured on the minus No. 4 sieve
size) should be considered moisture -sensitive. Use of moisture -sensitive soil in structural fills
should be limited to favorable dry weather conditions. The on -site till soils generally
contained significant amounts of silt and are considered moisture -sensitive. In addition,
construction equipment traversing the site when the soils are wet can cause considerable
disturbance. If fill is placed during wet weather or if proper compaction cannot be obtained, a
select import material consisting of a clean, free -draining gravel and/or sand should be used.
Free -draining fill consists of non -organic soil with the amount of fine-grained material limited
to 5 percent by weight when measured on the minus No. 4 sieve fraction and at least 25
percent retained on the No. 4 sieve.
A representative from our firm should inspect the stripped subgrade and be present during
placement of structural fill to observe the work and perform a representative number of in -
place density tests. In this way, the adequacy of the earthwork may be evaluated as filling
progresses and problem areas may be corrected at that time. It is important to understand that
taking random compaction tests on a part-time basis will not assure uniformity or acceptable
performance of a fill. As such, we are available to aid the owner in developing a suitable
monitoring and testing frequency.
10.0 FOUNDATIONS
Spread footings may be used for building support when founded on medium dense to dense
lodgement till, or structural fill placed as previously discussed. We recommend that an
allowable bearing pressure of 2,500 pounds per square foot (psf) be utilized for design
purposes, including both dead and live loads. An increase of one-third may be used for short-
term wind or seismic loading. Perimeter footings should be buried at least 18 inches into the
surrounding soil for frost protection. However, all footings must penetrate to the prescribed
bearing stratum and no footing should be founded in or above loose, organic, or existing fill
soils.
It should be noted that the area bounded by lines extending downward at 1H:1V from any
footing must not intersect another footing or intersect a filled area which has not been
compacted to at least 95 percent of ASTM: D 1557. In addition, a 1.5H:1 V line extending
down from any footing must not daylight because sloughing or raveling may eventually
undermine the footing. Thus, footings should not be placed near the edge of steps or cuts in
the bearing soils.
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Subsurface Exploration, Geologic Hazard, and
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Design Recommendations
Anticipated settlement of footings founded on suitable till or approved structural fill should be
on the order of 3/ inch. However, disturbed soil not removed from footing excavations prior
to footing placement could result in increased settlements. All footing areas should be
observed by AESI prior to placing concrete to verify that the design bearing capacity of the
soils has been attained and that construction conforms to the recommendations contained in this
report. Such observations may be required by the governing municipality. Perimeter footing
drains should be provided as discussed under the section on Drainage Considerations.
11.0 FLOOR SUPPORT
A slab -on -grade floor may be used over structural fill or pre -rolled, medium dense to very
dense natural ground. The floor should be cast atop a minimum of 4 inches of washed pea
gravel or other suitable material approved by the geotechnical engineer to act as a capillary
break. It should also be protected from dampness by an impervious moisture barrier or
otherwise sealed.
Another alternative would be to utilize a structural floor or crawl space -type construction.
With this approach, floor support problems resulting from site disturbance are eliminated. If
surficial soils are disturbed, the foundations can be excavated through the loose soils to suitable
bearing and floor support is unaffected. Thus, a structural or crawl space floor is better suited
to wet weather construction than is slab -on -grade, although either system can be specified. In
the case of a crawl space, the soil below the floor system should be covered with an
impervious moisture barrier to reduce dampness.
12.0 DRAINAGE CONSIDERATIONS
The till soils are relatively impermeable and water will tend to perch atop this stratum.
Additionally, traffic across these soils when they are damp or wet will result in disturbance of
the otherwise firm stratum. Therefore, prior to site work and construction, the contractor
should be prepared to provide drainage and subgrade protection, as necessary.
All footing walls should be provided with a drain at the footing elevation. Drains should
consist of rigid, perforated, polyvinyl chloride (PVC) pipe surrounded by washed pea gravel.
The level of the perforations in the pipe should be set down at the bottom of the footing at all
locations and the drains should be constructed with sufficient gradient to allow gravity
discharge away from the buildings. In addition, all retaining walls should be lined with a
minimum, 12-inch-thick, washed gravel blanket provided over the full height of the wall to
within 12 inches of final grade and which ties into the footing drain. Roof and surface runoff
should not discharge into the footing drain system, but should be handled by a separate, rigid,
tightline drain. In planning, exterior grades adjacent to walls should be sloped downward
away from the structures to achieve surface drainage.
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Design Reconunendations
13.0 PROJECT DESIGN AND CONSTRUCTION MONITORING.
At the time of this report, site grading, structural plans, and construction methods have not
been finalized and our recommendations are preliminary. We are available to provide
additional geotechnical consultation as the project design develops and possibly changes from
that upon which this report is based. We recommend that AESI perform a geotechnical review
of the plans prior to final design completion. In this way, our earthwork and foundation
recommendations may be properly interpreted and implemented in the design. This review is
not included in our current scope of work or budget.
We are also available to provide geotechnical engineering and monitoring services during
construction. The integrity of the foundations depends on proper site preparation and
construction procedures. In addition, engineering decisions may have to be made in the field
in the event that variations in subsurface conditions become apparent. Construction monitoring
services are not part of this current scope of work. If these services are desired, please let us
know and we will prepare a proposal.
We have enjoyed working with you on this study and are confident that these recommendations
will aid in the successful completion of your project. Should you have any questions or
require further assistance, please do not hesitate to call.
Sincerely,
ASSOCIATED EARTH SCIENCES, INC.
Kirkland, Washington
THO
33598
�SSIGNAL E��� S�z��°r
0
E(PIRES: 0 3 /0 t o
Maire Thornton, P.E.
Senior Project Engineer
p'X0
Jon N. Sondergaard, P.G. , P.E.G.
Senior Associate Geologist
Attachments: Figure 1: Vicinity Map
Figure 2: Site and Exploration Plan
Appendix: Exploration Logs EP-1 through EP-6
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