PLN200300115-10382.PDFlow
CITY OF EDMONDS
121 - 5TH AVENUE NORTH, EDMONDS, WA 98020
PLANNING DIVISION
STAFF REPORT
FINDINGS, CONCLUSIONS, AND DECISION
To: File, SD-2003-115
From
Star Campbell
Planner
Date: NOVEMBER 17, 2003
File: SD-2003-115
7425 OLYMPIC VIEW DRIVE, STEEP SLOPE EXEMPTION
Decision Date: NOVEMBER 17, 2003
TABLE OF CONTENTS
Section Page
I. INTRODUCTION..............................................................................................................2
A.
APPLICATION.....................................................................................................................................2
B.
DECISION...........................................................................................................................................2
II. FINDINGS OF FACT AND CONCLUSIONS................................................................2
A.
SITE DESCRIPTION.............................................................................................................................
2
B.
EDMONDS COMMUNITY DEVELOPMENT CODE (ECDC) COMPLIANCE..............................................3
C.
TECHNICAL COMMITTEE....................................................................................................................7
I. RECONSIDERATIONS AND APPEALS.......................................................................7
II. APPENDICES....................................................................................................................8
III. PARTIES OF RECORD...................................................................................................8
SD-03-1 15srtakethree.doc / November 17, 2003 / Staff Report
File No. SD-03-115
Page 2 of 7
I. INTRODUCTION
Paul Stromme, on behalf of the owners, Dave and Julie Clobes has submitted a Steep
Slope Exemption application to allow for an addition to the Clobes' residence at 7425
Olympic View Dr. This site contains a "Steep Slope Hazard Area." A "Steep Slope
Hazard Area" is defrted by the Critical Areas Chapter of the Edmonds Community
Development Code (ECDC) as a slope of at least 40% within the broader category of
"Geologically Hazardous Areas." The ECDC does not allow for any development or
alteration of Steep Slope Hazard Areas unless an exemption has been granted.
The procedure for obtaining a Steep Slope Exemption involves the preparation of a
geotechnical analysis of the site by a State licensed Geotechnical Engineer. This analysis
must demonstrate that the site has certain physical features and that the proposed
development meets a specific list of characteristics as specified in the Steep Slope
Exemption section of the Critical Areas Ordincance. In addition, the development must
not compromise the stability of the site or any adjacent sites. Through the review process
for the Steep Slope Exemption, the applicant was unable to demonstrate that the site had
all the physical features necessary to allow it to qualify for a Steep Slope Exemption. The
following is Staff s review and analysis of the Steep Slope Exemption application:
A. Application
1. Applicants: Dave and Julie Clobes.
2. Site Location: 7425 Olympic View Dr. (See Attachment 1).
3. Request: Steep Slope Exemption
4. Review Process: Staff Decision
5. Maior Issue: Compliance with Edmonds Community Development Code
(ECDC) Chapter 20.15B.110.D.2. (CRITICAL AREAS)
B. Decision
Based on statements of Fact, Conclusions, and Attachments in this report the Steep Slope
Exemption request does not meet all of the exemption criteria and is therefore DENIED.
II. FINDINGS OF FACT AND CONCLUSIONS
A. Site Description
1. Site Development and Zoning:
a) Facts:
(1) Zoning: The zoning of the subject property is Single Family Residential
(RS-12). (See Attachment 1)
(2) Current Land Use: The lot is currently developed with a Single -Family
Residence.
SD-03-115srtakethree.doc / November 17, 2003 / Staff Report
File No. SD-03-115
Page 3 of 7
(3) Proposed Development: The applicants are proposing to construct an
addition to their residence. See Attachment 2.
(4) Terrain and Vegetation: The lot rises gently in a general south to north
direction over much of the lot and then just to the north of the house rises
steeply. See Figure 2 of Attachment 3. Vegetation around the house
consists of residential landscaping. The slope has several large evergreens
and ivy undergrowth.
2. Neighboring Development and Zoning:
a) Fact: The surrounding properties are zoned and developed to the "Single -
Family Residential' (RS-12) designation. (See Attachment 1)
b) Conclusion: The proposal would allow the continued development of the lot
with a single-family residence. This is consistent with the surrounding
development.
B. Edmonds Community Development Code (ECDC) Compliance
1. Compliance with requirements for a Steep Slope Exemption
Section D of ECDC Chapter 20.15B.110 (Development Standards- Geologically
Hazardous Areas) addresses development in Steep Slope Hazard Areas. This section
states that no development or alteration shall be allowed in steep slope hazard areas
unless the property qualifies for an exemption or exception under the provisions of
this section.
a) Facts:
(1) ECDC Section 20.15B.110.D.2 establishes the following list of criteria that
must be met in order for a development or alteration to qualify for an
exemption:
(a) The proposed development will not decrease stability on any
adjacent property, and the site following the permitted activity will
be stable.
(b) The development will occur on steep slope areas that either are
mapped as one of the following deposits on the "Geological Map of
the Edmonds East and part of the Edmonds West Quadrangles", by
James P. Minard: Till, Advance Outwash, and/or Olympia Gravel or
on steep slope areas comprised of fill placed under engineered
conditions on stable geological deposits of these same soils. The fill
must meet the following conditions: all fill was placed under a legal
grading permit, the grading and fill were designed by a licensed
professional engineer, native soils beneath the fill were prepared in
accordance with the engineering design, and compaction testing
confirms that uniform compaction to the specified percentage is
present throughout the entire fill.
(c) All excavations on steep slopes will not extend below a 35-degree
plane extended down from the property lines, unless the excavation
is retained by structural shoring. The shoring must be designed by a
registered professional engineer.
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�IlllllllrFile No. SD-03-115
Page 4 of 7
(d) All retaining structures on steep slopes shall be engineered
structures conforming to the State Building Code and rockeries
greater than four feet in height are not permitted.
(e) Steep slope areas cannot be altered if one or more of the following
conditions are on or adjacent to the steep slope: impermeable soils
interbedded with granular soils, springs or groundwater seepage,
significant visible evidence of groundwater seepage, previous
landsliding or instability, or existing landslide deposits.
(f) Steep slope areas cannot be altered if the thickness of organics,
debris, weathered soils, collovial soils or soils exhibiting loose
conditions on or adjacent to the steep slope exceed three feet.
(g) A buffer of 15 feet shall be retained in an undisturbed condition
from commercial development to property lines of adjacent
residential properties.
(2) ECDC Section 20.15B.110.F states the requirement that all applications for
development proposals within geologically hazardous areas shall be
accompanied by a written site analysis by a geologist or geotechnical
engineer licensed by the state of Washington. A peer review of this
document is also required.
(3) The applicant submitted a geotechnical report by HWA Geosciences Inc.
that addresses the Steep Slope Exemption Criteria (See pages 4 through 6 of
Attachment 3).
(4) The criterion that states that, "The proposed development will not decrease
stability on any adjacent property, and the site following the permitted
activity will be stable" is addressed on page 4.
(a) The report, in specifically addressing this criterion, does not
specifically state that the development will not decrease stability on
the site or on adjacent sites.
(b) This section does state that, "the excavation could impact the 10-foot
exception zone shown on Figure 2" and that, "...the short term risk
of slope instability on the subject property will be low."
(c) A statement is made in another section of the report on page 3 that,
the project, "can be safely achieved without impacting the stability
of the adjacent, upslope property."
(5) The criterion that addresses the types of soil deposits required on the site as
stated in the above Section II.B.l.a).(1).(b) of the Staff Report is addressed
on pages 4 and 5 of the HWA report (Attachment 3). It states that the site is
mapped as one of the allowed types of deposits and that the fill at the site
should be removed.
(6) The criterion that states that, "All excavations on steep slopes will not
extend below a 35-degree plane extended down from the property lines,
unless the excavation is retained by structural shoring... designed by a
registered professional engineer" is addressed on page 5 of the report.
SD-03-115srtakethree.doc / November 17, 2003 / Staff Report
L
. File No. SD-03-115 �
Page 5 of
(a) The report states that the excavation will not extend below a 35
degree plane drawn from the lot line but does extend below a 35
degree plane drawn from the edge of the exception zone. Since this
exception zone is actually not part of the property, it appears that the
excavation will extend below a 35 degree plane extended down from
the north property line.
(b) A rockery is referred to (see below Section II.B. La).(7).(d) of the
Staff Report that apparently would also intersect this 35 degree
plane. There is no statement made to indicate whether or not the
project design will utilize structural shoring. However, this is a
requirement that may be incorporated into the project as a condition
of construction.
(7) The criterion that states that, "All retaining structures on steep slopes shall
be engineered structures conforming to the State Building Code and
rockeries greater than four feet in height are not permitted" is addressed on
page 5 of the report.
(a) The report states that, "retaining structures should be engineered in
conformance with the Building Code," and refers to an
approximately 8' high rockery that is planned. This rockery is
shown in Figure 5 of the report.
(b) Rockeries are not considered by the City of Edmonds Building
Division to be retaining walls. Rockeries are traditionally used for
landscaping and/or erosion control and have less restrictive
structural standards than retaining walls.
(c) The City of Edmonds Building Division recognizes that retaining
walls may be used for soils that are not capable of standing or
remaining at the existing slope. Retaining walls must be designed
based on standard engineering methods provided by the Uniform
Building Code and WSDOT/APWA Standard specifications for
Road, Bridge, and Municipal Construction.
(d) A rockery is referred to on page 8 of the report. This would be an
extension of the existing rockery to the north of the house. It would
be located to the north of a deck that would be built behind the
addition and a maximum of 8 feet high. The extension of the deck
and rockery is not shown on the project site plan (Attachment 2) or
the HWA report Figure 2 site plan or Figure 3 cross section.
(e) It is not clear whether the proposed rockery functions as a retaining
structure.
S13-03-115srtakethree.doc / November 17, 2003 / Staf Report
` ' File No. SD-03-115
7 Page 6 of 7
(8) The criterion that states that, "Steep slope areas cannot be altered if one or
more of the following conditions are on or adjacent to the steep slope:
impermeable soils interbedded with granular soils, springs or groundwater
seepage, significant visible evidence of groundwater seepage, previous
landsliding or instability, or existing landslide deposits" is addressed on
pages 5 of the report. The report states that, "No impermeable soils
interbeddd within the advance outwash were encountered; no seepage was
encountered, or evidence of previous seepage noted; and no signs of slope
instability observed."
(9) The criterion that states that, "Steep slope areas cannot be altered if the
thickness of organics, debris, weathered soils, collovial soils or soils
exhibiting loose conditions on or adjacent to the steep slope exceed three
feet' is addressed on pages 5 and 6 of the report. The report states that loose
soils were encountered from 3.5 to 7.5 feet deep in two of the four test pits at
the site.
(10)The criterion that states that, "a buffer of 15 feet shall be retained in an
undisturbed condition from commercial development to property lines of
adjacent residential properties" is not applicable to this project as the project
is not considered to be commercial development.
(I I)A peer review document by Geo Group Northwest that addresses the Steep
Slope Exemption criteria has been included, as Attachment 4. This report
concludes, on page 2, that the proposal does not satisfy the Steep Slope
Exemption criteria that has to do with the depth of loose soils at the site.
b) Conclusions:
(1) Staff has reviewed the geotechnical report by HWA Geosciences Inc.
(Attachment 3). In addition, Staff has reviewed and taken into consideration
the peer review report provided by Geo Group Northwest, Inc. (Attachment
4).
(2) The criteria that have to do with the aspects of the development as stated in
above Sections II.B.I.a).(1).(a).,(c), and (d) of the staff report may
potentially be dealt with as conditions of approval. If further information is
required in order to more fully demonstrate that the development will meet
these criteria, this can be required with the review of the building permit for
the development.
(3) For this project, additional information would be needed to ensure that
aspects of the development would qualify for a Steep Slope Exemption as
follows: a specific statement would need to be made by the project
geotechnical engineer that, "the proposed development will not decrease
stability on any adjacent property, and the site following the permitted
activity will be stable;" if any proposed alteration of the slope extends
beyond a 35 degree plane extended down from the property lines, structural
shoring would need to be utilized; construction plans would need to show
that the project would not include any rockeries greater than four feet in
height and that all retaining structures were engineered structures
conforming to the State Building Code.
SD-03-115srtakethree.doc / November 17, 2003 / Staff Report
�, �. File No. SD-03-115
Page 7 of 7
(4) hi order for a Steep Slope Exemption to be approved with the conditions that
specific aspects of the development will meet the criteria for a Steep Slope
Exemption, it must be apparent that the specific site standards required for a
Steep Slope Exemption can be met.
(5) The criteria that have to do with the specific characteristics of the property
as stated in above Sections II.B.l.a).(1).(b).,(e), and (f) of the staff report
appear to have been met with the exception of the criterion that states that,
"steep slope areas cannot be altered if the thickness of organics, debris,
weathered soils, collovial soils or soils exhibiting loose conditions on or
adjacent to the steep slope exceed three feet."
(6) Since this criterion may not be met, the Steep Slope Exemption should be
denied.
2. Compliance with Public Notification Requirements
a) Facts:
(1) ECDC 20.15B.I 10.D.3 requires Steep Slope Exemptions to be processed as
staff decisions with public notification required as regulated by ECDC
20.95.050.
(2) A notice of application was posted for public comment on August 22, 2003.
There was a two -week public comment period that ended on September 5,
2003.
(3) There were no public comments received.
b) Conclusion: The City and the Applicant have complied with the requirements
for public notification.
C. Technical Committee
Review by City Departments: The application has been reviewed and evaluated by the
Engineering Division and the Fire Department, Public Works Department and Parks and
Recreation Department. There were no comments received related to the Steep Slope
Exemption proposal.
III. RECONSIDERATIONS AND APPEALS
A. Reconsideration of Decision
A request for reconsideration or clarification of this decision may be made by filing a
letter with the Planning Department by December 2 2003. This is within ten (10)
working days of the mailing of this notice (see mailing date below).
B. The Right to Appeal
This decision may be appealed to the Hearing Examiner. In this case, a written appeal
letter must be submitted with the required appeal fee to the Planning Department by
December 1.2003. This is within fourteen (14) calendar days of the mailing of this
notice (see mailing date below).
SD-03-115srtakethree.doc / November 17, 2003 / Staff Report
File No. SD-03-115
*AW Page 8 of 7
City of Edmonds, Attn.: Planning Division
121- 5th Avenue North
Edmonds, Washington 98020
DATE MAILED: November 17, 2003
IV. APPENDICES
Attachments 1 through 4:
1. Vicinity and Zoning Map
2. Project Site Plan
3. Geotechnical Report by HWA Geosciences Inc. dated July 3, 2003.
4. Geotechnical Peer Review Addendum by Geo Group Northwest Inc. dated September
26, 2003.
V. PARTIES OF RECORD
Dave and Julie Clobes
7425 Olympic View Dr.
Edmonds, WA 98026
Paul Stromme
9623 8th Ave. NE
Seattle, WA 98115
SD-03-115srlakethree.doc / November 17, 2003 / Staff Report
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HWAGEOSCIENCES INC
19730-64TH AVE. W., SUITE 200
LYNNWOOD, WA 98036-5957
Jul 3 2003 TEL. 425-774-0106
' Y I FAX. 425-774-2714
HWA Project No. 2003082-21 E-MAIL hwa@hongwest.com
Mr. David Clobes
7425 Olympic View Drive
Edmonds, Washington 98026
Subject: GEOTECHNICAL REPORT
Proposed Extension to Residence
7425 Olympic View Drive, Edmonds, Washington
' Dear Mr. Clobes;
This report presents the results of a geotechnical investigation, undertaken for a proposed
extension to the northeast end of your residence, at 7425 Olympic View Drive in Edmonds,
Washington (Figure 1). The proposed extension is located on a slope defined as a Steep
Slope Hazard Area in the City of Edmonds Municipal Code (EMC). The purpose of this
' report is to investigate whether the proposed extension can be safely constructed as planned,
and is consistent with the requirements of the EMC. Our work included a site
reconnaissance, subsurface explorations, laboratory testing, and engineering analyses to
' develop our results and conclusions.
PROJECT DESCRIPTION
We understand that the planned 2-story extension will have footprint dimensions of 22 feet
by 30 feet (Figure 2), and floor elevations will match those of your existing house (main
' floor at El. 304.37 feet and upper floor at El. 313.12 feet). Excavation to a maximum depth
of about 12 feet below existing ground surface is required. An extension is also planned for
the western end of the house, but is not impacted by steep slope requirements.
' SITE DESCRIPTION AND OBSERVATIONS
The lot has approximate dimensions of 160 feet by 90 feet and is located on the northeast
' side of the intersection of Olympic View Drive and Homeview Drive (Figure 2). Residential
lots border the north and east sides of the property. The steep slope area is located along the
north property line. The ground surface slopes southwards at about 56%, but is locally as
' steep as 109% near the northeast property line. The top of the slope is at about El. 330 feet
which is 26 feet above the lower floor elevation (El. 304.37 feet). Figure 3 prCREG I-V E D
section of the slope at the proposed extension.
' JUL 17 2903
We observed the following: PERMIT COUNTER
' • There are no signs of previous slope instability, or evidence of slope creep
inferred from trees with bent trunks. The steepest slope segment of 109% near
' the northeast corner has been locally steepened as a result of dumping of garden.
GEOLOGY
GEOENVIRONMENTAL SERVICES
HTDROREU 0Y
GETpNQLLaff3
July 3, 2003 �Qw `'
HWA Project No. 2003082-21
refuse over many years.
1
• Slope vegetation consists mainly of ivy with several large coniferous trees. No
vegetation that is typically indicative of seepage or very moist conditions was
noted.
• The slope is undeveloped, but the surface has been disturbed possibly by
excavated material dumped during the construction of the original house. A
boardwalk provides access across the slope, and a small shed is present at the foot
of the slope. A manhole is present a short distance above the toe of the slope. We
understand this manhole previously discharged to a now abandoned septic
absorption system at the foot of the slope.
• We understand that at grade parking is present over a portion of the planned
extension area, but this was filled some years previously with sawdust.
• A rockery is located about 10 feet from the northern side of the house to provide a
private deck. The deck is at El. 313.04 feet and the rockery is about 7 feet high.
The rockery shows no signs of instability, or seepage through the wall.
SUBSURFACE EXPLORATIONS
The site was explored by means of 4 hand auger borings (designated HH-1 through H14-4)
supplemented with drop -weight cone penetration (DCP) tests. The DCP test consists of a
sliding hammer weighing 17.5 pounds which free -falls through a vertical drop of 22.5 inches.
The cone has a %-inch diameter and 600 apex angle. Test results are obtained by recording
penetration for each 5 blows. In order to facilitate comparison with Standard Penetration
Test (SPT) N-values, the penetration results are converted into equivalent number of
blowstfoot for the length driven. SPT N-value is approximately equal to the DCP blow count
expressed in equivalent blows/foot over the range of 3 to 20 blows/foot.
Pertinent information including soil description and engineering characteristics, stratigraphy,
and ground water occurrence are recorded on the attached soil logs (Appendix A). The
stratigraphic contacts shown on the logs represent the approximate boundaries between soil
types; actual transitions may be more gradual. It should be noted that the soil and ground
water conditions depicted are only for the specific dates and locations reported and,
therefore, are not necessarily representative of other locations and times. It is anticipated that
' water conditions will vary depending on seasonal precipitation, local subsurface conditions
and other factors.
SUBSURFACE CONDITIONS
The geological map by Minard, J.P (1983), "Geologic Map of the Edmonds East and Part of
the Edmonds West Quadrangles", indicates that the slope consists of advance outwash
comprising mostly clean, pebbly sand with fine-grained sand and silt common in the lower
part of the unit. Glacial till is present at the top of the slope. Undisturbed advance outwash
2003092.21 Geotechnical Report 2 HWA GEOScMNCEs INc.
July 3, 2003 1 "° ` W
HWA Project No. 2003082-21
is typically dense to very dense. Slopes in glacial outwash, typically slough to the angle of
repose of the sand of around 300 to 330. When slope instability occurs in glacial outwash, it
is mainly confined to loose surficial layers, but deep' -seated slides can occur near the contact
with less permeable glacial silts and clay near the base of the deposit.
The explorations encountered a thin organic topsoil layer, over very loose to loose, fine to
medium sand with a trace to some silt and occasional gravel, over medium dense, slightly
gravelly fine to medium sand, and occasional gravel layers. The depth of loose sand on the
slope was 3 feet at HH-1, 7.5 feet at HH-2, and 3.75 feet at HH4. Because the holes kept
collapsing, the conditions at depth were interpreted from the DCP penetration rates.
iA profile drawn through the eastern side of the proposed extension is shown in Figure 3. Our
interpretation of the soil profile and observation of the site topography indicates that the deep
pocket of loose material encountered at HH-2 (and absent at HH-4) is likely dumped material
from the original house construction.
No indication of seepage was encountered in any of the holes or DCP soundings.
CONCLUSIONS AND RECOMMENDATIONS
GENERAL
The investigation shows the slope consists mainly of advance outwash, but pockets of loose
to very loose surficial material occur which are likely deposits of dumped fill resulting from
the original basement and rear yard deck excavation. Exploration HH-2 shows that these
pockets can be of 7.5 feet deep. In addition, a large amount of garden refuse has been
dumped on the slope producing the over -steepened slope near the northeast property corner.
We consider that the planned basement excavation into the slope can be safely achieved
without impacting the stability of the adjacent, upslope property. In addition, provided that
the design and construction of the extension takes account of the loose material blanketing
the slope, the basement excavation will improve the stability of the slope. An important
factor in achieving a safe excavation is providing adequate temporary excavation slopes or
using shoring during excavation and construction of the basement walls. The basement wall
must be designed to carry the lateral loads imposed by the loose sand.
We did not observe seepage in the explorations, and understand that no seepage has been
encountered in the existing basement. Despite this, we recommend that footing drains
(Figure 4) be installed around the perimeter of exterior walls and at the toe of retaining walls
because the presence of some silt could result in the outwash being somewhat less than free -
draining during very wet periods.
' EDMONDS MUNICIPAL CODE REQUIREMENTS FOR STEEP SLOPES
In this section, extracts from the Edmonds Municipal Code (EMC) relating to steep slopes
are summarized with responses pertaining to the subject property following in italics.
2003082-21 Ce technical Report 3 HWA GEOSCIENCES INC.
July 3, 2003 �%w �'"
HWA Project No. 2003082-21
1
Steep Slope Hazard Area
The EMC defines Landslide Hazard Areas as "those areas of the City of Edmonds which, by
reason of excessively steep slopes, unsatisfactory foundation support, stability or topography,
have a risk of earth subsidence and landslide hazard in excess of normal allowances". We
'
understand that the slope occurring on the subject property is classified as a Steep Slope
Hazard Area "because the ground rises at an inclination of 40% or more within a vertical
elevation change of at least 20 feet". The EMC indicates that a slope is delineated by
establishing its toe and top and measured by averaging the inclination over at least 20 feet of
vertical relief.
1
The subject property is classified as a Steep Slope Hazard Area because the average slope
angle through the building extension is 46% (about 25 degrees). Localized sections with
vertical relief of about 10 feet occur where the slope angle is steeper, e.g. 56% and 57%
above the extension, and 109% at the northeast corner.
Development in Steep Slope
Areas
According to the EMC, no development or alteration is allowed in Steep Slope Hazard areas
unless the property is exempt, a reasonable use exception has been granted, or a variance has
been granted. A development may be exempted if it meets the following criteria summarized
'
from Clause 20.15B.I 10:
1. The proposed development will not decrease stability on any adjacent property, and the
site following the permitted activity will be stable as demonstrated by engineering
analysis meeting requirements of the Building Code.
Temporary excavation for the basement will extend close to a line drawn at 350 from
the north Lot Line (Figure 2) as shown on Figure 3 and so would have no impact on the
adjacent property. However, the excavation could impact the 1 D foot Exception shown
'
on Figure 1. Further, provided the excavation is sloped, benched, or shored in
accordance with Part N of Washington Administrative Code (WAC) 296-155, the short-
term risk of slope instability on the subject property will be low. The excavation should
be undertaken in dry weather and the slope should be adequately protected
I2.
The development is located on steep slope areas that are either mapped as till, advance
outwash or Olympia gravel, or are composed of engineered fill placed under engineered
conditions on stable geologic deposits. All fill should have been placed under a legal
grading permit, with the grading and fill designed by a licensed professional engineer,
native soils beneath the fill prepared in accordance with the engineering design, and
compaction testing confirms that uniform compaction to the specified percentage is
present throughout the entire fill.
1 2003082.21 GeotminicW Repo" 4 HWA GEGSCIENCES INC.
July 3, 2003 �%W
HWA Project No. 2003082-21
�%W
The geological map and our explorations show that the general area is underlain by
advance outwash. Pockets of very loose fill of up to 7.5 feet deep are present near the
foot of the slope. The excavation to accommodate the basement should be extended, as
required, to remove this loose material, and so enhance long-term stability of the slope.
Building foundations will be established on advance outwash.
3. All excavations on steep slopes shall not extend below a 350 plane extended down from
the property lines, unless the excavation is retained by.structural shoring. The shoring
must be designed by a registered professional engineer.
Figure 3 shows the excavation will not extend below a 350 plane drawn from the Lot
line, but does extend below a 350 plane drawn from the edge of the Exception zone.
4. All retaining structures on steep slopes shall be engineered structures conforming to the
n
IJ
11
11
r
I
E
Building Code; rockeries are not permitted greater than four feet in height.
It is agreed that retaining structures should be engineered in conformance with the
Building Code. The existing rockery appears to be performing adequately. Details of a
a rockery designed to support a 10 foot high slope along the outside of the deck are
shown in Figure 5.
5. Steep slopes cannot be altered if one or more of the following conditions are present on
or adjacent to the portion of the subject property classified as a steep slope;
impermeable soils interbedded with granular soils, springs or groundwater seepage,
significant visible evidence of groundwater seepage, previous landsiiding or instability,
or existing landslide deposits. "On or adjacent to" includes those areas upslope and
downslope of the steep slope, within a horizontal distance from the toe onop of the
slope equal to two times the vertical height of the steep slope.
No impermeable soils interbedded within the advance outwash were encountered; no
seepage was encountered, or evidence ofprevious seepage noted; and no signs ofslope
instability observed.
6. Steep slopes cannot be altered if the thickness of organics, debris, weathered soils,
colluvial soils or soils exhibiting loose conditions (as measured by the Standard
Penetration Test (ASTM D1586)) on or adjacent to the portion of the subject property
classified as a steep slope exceeds 3 feet.
The explorations show that the loose soil thickness is 3 feet at HH-1, 7.5 feet at HH-2,
and 3.75 feet at HH-4. However, based on our explorations, we consider that much of
the loose soil is fill dumped near the base of the slope during original house
2003082.21 Geacchnical Report 5 HWA GEOSC04CES INC.
' July 3, 2003 %W
HWA Project No. 2003082-21
construction. We are convinced that basement excavation will improve slope stability
1 by removing most of the loose fill.
EXCAVATIONS
Temporary Excavation Slopes
Maintenance of safe working conditions, including temporary excavation stability, should be
the responsibility of the contractor. All temporary cuts in excess of 4 feet in height should be
sloped, benched, or shored in accordance with Part N of Washington Administrative Code
(WAC) 296-155. The loose sandy material classifies as Type C soil. Temporary
unsupported excavations in Type C soils should be sloped no steeper than 1%H:1 V
' (approximately 34). The recommended maximum inclinations for temporary slopes
assumes that the ground surface behind the cut slope is level and surface loads from
equipment and materials are kept a sufficient distance away from the top of the slope. As
evident from Figure 3, steeper slopes than permitted by WAC regulations will likely be
necessary to facilitate construction of the back wall of the proposed extension.
With time and the presence of seepage and/or precipitation, the stability of temporary
unsupported cut slopes can be significantly reduced. Therefore, temporary slopes should be
protected from erosion by covering the cut face with well -anchored plastic sheeting. The
contractor should monitor the stability of temporary cut slopes and adjust the construction
schedule and slope inclination accordingly.
Temporary Shoring
Due to the required excavation depth and the loose sandy soils, temporary braced shoring
would likely be preferred to reduce the volume of excavation required to accommodate
temporary unsupported slopes. Various cantilevered shoring systems consisting of sheet
piles, or soldier piles and lagging could be considered, as well as alternative systems using
steel plates and bracing, or trench boxes.
The temporary shoring system should be designed and constructed to support lateral loads
exerted by the retained soil mass and any surcharge at the ground surface. Lateral earth
pressures for design of temporary shoring can be provided when the shoring system is
selected.
STRUCTURAL FILL MATERIALS AND COMPACTION
For the purposes of this report, material used to raise grades or placed under structures is
' classified as structural fill. Imported structural fill should consist of clean, free -draining,
granular soils that are free from organic matter or other deleterious materials. Such materials
should comprise particles of less than 4-inch maximum dimension, with less than 7% fines
2003082-21 Geotechnical Report 6 - HWA GEOSCIENCES INC.
July 3, 2003
HWA Project No. 2003082-21
(portion passing the U. S. Standard No. 200 sieve), as specified for "Gravel Borrow" in
Section 9-03.14(1) of the WSDOT Standard Specifications (WSDOT, 2000). The fine-
grained portion of structural fill soils should be non -plastic.
' Structural fill soils should be moisture conditioned, placed in loose horizontal lifts less than
8-inches thick, and compacted to at least 95% of the maximum dry density as determined
using test method ASTM D 1557 (Modified Proctor). Achievement of proper density of a
compacted fill depends on the size and type of compaction equipment, the number of passes,
thickness of the layer being compacted, and soil moisture -density properties. In areas where
limited space restricts the use of heavy equipment, smaller equipment can be used, but the
soil must be placed in thin enough layers to achieve the required relative compaction.
Generally, loosely compacted soils result from poor construction technique or improper
moisture content. Soils with high fines contents are particularly susceptible to becoming too
wet, and coarse -grained materials easily become too dry, for proper compaction.
SEISMIC CONSIDERATIONS
The project site lies within Seismic Zone 3 as defined in the 1997 Uniform Building Code
I (UBC). Zone 3 includes the western portion of Washington and represents an area of
relatively high seismic risk. We recommend that a soil profile type So be used for design.
I The absence of ground water or seepage means that the slope materials are not susceptible to
liquefaction during a design level (1:475 year recurrence interval) earthquake.
IFOUNDATIONS
Design Considerations
Spread and strip footings may be used for the building extension and should extend through
all loose material onto medium dense (or better) undisturbed advance outwash. All exterior
footings should be founded at least 18 inches below the lowest adjacent finished grade;
interior footings should be founded a minimum of 12 inches below the top of adjacent slabs
or floors.
I The footings should designed for a maximum allowable bearing pressure of 2,000 psf,
subject to minimum footing widths of 18 and 24 inches for continuous strip and isolated
column footings, respectively. The recommended maximum allowable bearing pressure may
be increased by 1/3 for short-term transient conditions such as wind and seismic loading.
Provided construction is accomplished as recommended herein, and for the foundation loads
anticipated, we estimate differential settlements between adjacent load -bearing structures to
be less than I- inch.
I
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2003082-21 Gmtechnical Report 7 HWA GEOSCIENCES INC.
July 3, 2003
HWA Project No. 2003082-21
Construction Considerations
All footing excavations should be trimmed neat and the excavation bottoms should be
carefully prepared such that over -excavation of native soils is avoided. All loose or softened
soil should be removed from the footing excavation prior to placing reinforcing steel. We
recommend that HWA observe footing excavations prior to pouring concrete to verify that
the recommendations of this report have been followed and that an appropriate bearing
stratum has been exposed.
If footing excavations are open during the winter or periods of wet weather, we recommend
that a lean concrete mat or mud -slab, be placed to help preserve the subgrade until the
footings are poured.
BASEMENT WALLS RETAINING WALLS
AND
Although, concrete basement retaining walls will be utilized for the building extension, we
understand a rockery matching the existing would be preferred along the outside of the deck
area. Maximum rockery height would be about 8 feet, and exceeds the maximum height of 4
feet allowed for rockeries in the EMC. We believe that a rockery with the details shown in
Figure 5 would be suitable, but if the City does not accept a matching rockery, we
recommend either a reinforced concrete cantilever or segmental block retaining wall.
Alternatively, consideration should be given to extending the basement wail to existing
ground surface, and not providing a flat deck behind the new extension.
1 We recommend that for areas of level backfill (i.e. basement wall if deck provided), an at -
rest equivalent fluid density of 55 pounds per cubic foot (pcf) be used to determine design
lateral earth pressures. This value assumes that backfill behind the walls is horizontal and is
placed and compacted in accordance with our recommendations. For walls with sloping
backfill, the equivalent fluid density should be increased by 1 pcf for each degree of
1 backslope up to a maximum of 80 pcf for a wall with a backslope of 250 (existing ground
slope at location of building extension).
Fill within a distance of about 3 feet of the walls should be compacted with lightweight
equipment. Care must be taken to avoid over -compaction near the walls, or excessive lateral
pressures may develop.
Positive drainage should be provided behind the base of all subgrade and retaining walls to
prevent the buildup of hydrostatic pressures (see Figure 4).
Wind, earthquakes, and unbalanced earth loads will subject the wails to lateral forces, which
may be resisted by a combination of sliding resistance of the footing on the underlying soil
and passive earth pressure against the buried portions of the wall and footing. For design
purposes, a coefficient of friction of 0.4 may be assumed between the base of the footing and
' advance outwash. An allowable passive earth pressure equivalent to a fluid weighing 260
1 2003082-21 Geolechniu l Report 8 HWA GEOSCIENCES INC.
July 3, 2003 `W `"
HWA Project No. 2003082-21
pcf may be assumed for properly compacted fill placed against the sides of the foundations.
These recommended values assume drained conditions that will prevent the build-up of
' hydrostatic pressure in the compacted fill. The passive resistance provided by the upper 2
feet of soils should be neglected in design computations unless protection against excavation
is provided by pavement or a concrete slab. The recommended allowable passive earth
pressure value includes a factor of safety of about 1.5 for static conditions.
' SITE DRAINAGE
Roof drains should carry all runoff via a tightline to a storm drain or other appropriate outlet.
' Perimeter footing drains should be provided behind all subgrade and retaining walls as
shown in Figures 4 and 5. Roof downspouts and footing drains should not be connected to
' reduce the potential for clogging and back flooding of the perimeter drains.
EROSION CONSIDERATIONS
Erosion during construction can be minimized by careful grading practices, the appropriate
use of silt fences and/or straw bales. The excavated slope should be seeded and growth of
' vegetation should be encouraged as soon as possible after grading.
Surface runoff control during construction should be the responsibility of the contractor. All
' collected water should be directed under control to a positive and permanent discharge
system. Permanent control of surface water should be incorporated in the final grading
design. Water should not be allowed to pond immediately adjacent to foundations or paved
areas. Grading measures, slope protection, ditching, sumps, dewatering, and other measures
should be employed as necessary to permit proper completion of the work.
CONDTTIONS AND LIMITATIONS
We have prepared this letter report for use by David Clobes and his designated agents for use
in the design of an extension on the east side of the existing single-family residence on the
property. This report should be provided to prospective contractors for their bidding or
' estimating purposes, but conclusions and interpretations included in this letter report should
not be construed as our warranty of the subsurface conditions. Experience has shown that
soil and ground water conditions can vary significantly over small distances. Inconsistent
' conditions can occur between explorations and may not be detected by a geotechnical study.
If, during future site operations, subsurface conditions are encountered which vary
' appreciably from those described herein, HWA should be notified for review of the
recommendations of this letter report, and revision of such if necessary.
This report is issued with the understanding that it is the responsibility of the owner to ensure
that the information and recommendations contained herein are brought to the attention of
the appropriate design team personnel and incorporated into the project plans and
2003092-21 Geotechnical Report 9 HWA GEOSCIENCES INC.
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July 3, 2003 `e N%01
HWA Project No. 2003082-21
specifications. It is also the owner's responsibility to see that the necessary steps are taken to
verify that the contractor and subcontractors carry out these recommendations in the field. In
this regard, we recommend that HWA be retained to review the plans and specifications. We
also recommend that HWA be retained to monitor the geotechnical aspects of construction.
The scope of work did not include environmental assessments or evaluations regarding the
presence or absence of wetlands or hazardous substances in the soil, surface water, or ground
water at this site. This firm does not practice or consult in the field of safety engineering.
We do not direct the contractor's operations and we cannot be responsible for the safety of
personnel other than our own on the site; the safety of others is the responsibility of the
contractor. The contractor should notify the owner if any of the recommended actions
presented herein are considered unsafe.
O.O
We appreciate the opportunity to be of service. If you have any questions or concerns, please
do not hesitate to contact us.
Sincerely,
HWA GEOSCIENC
�Ta11
Brian E. Hall, P.E.
Senior Geotechnical Engineer
Enclosures:
Figure 1
Figure 2
Figure 3.
Figure 4
Figure 5
Appendix A:
' Figure Al
Figures A-2 - A-5
Vicinity Map
Site and Exploration Map
Geological Cross Section
Footing Drainage Requirements
Typical Rockery Details
ome o,
Principal
Legend of Terms and Symbols used on the Boring Logs
Logs of Explorations HH-1 through HH-4
2003082-21 Cmtechnical Report 10
HWA GEOSCIENCES INC.
I
1 1I IHWAMSMaSINc
NOT TO SCALE
VICINITY MAP DNA" BY 1
GLOBES RESIDENCE DH cm sv
7425 OLYMPIC VIEW DRIVE DATE
EDMONDS, WASHINGTON 7.01.03
1
2003-082
:
1 :..
UL 13Sdd0) v:m
N = N W
................... .... ...
1
(.S613Sdd0) Z-HH '
/ t�I N
1
(&.13Sdd0) f.'HR
i ; :N
1 3NI1 &la3dOUd
/...........................
i`
it NOLLd30X3',-
.I,
0 CD CD
m M m M
(133j) NOUVA313
1
Mz
Vg
� N
aZ
V
U ?�
N vi
W z
m0 J Z
U Ln f
n W
PAVEMENT I
IMPERVIOUS
SLOPED TO DRAIN
AWAY FROM STRUCTURE
GRANULAR
BACKFiLL
STABLE
EXCAVATION SLOPE
(Contractor's
Responsibility)
PEA
SUBDRAIN
NOT TO SCALE
MATE61AL3
Gravel Backfill for Drains shall meet the rodaGon
requirements specified in section 9-03.12g(4)
of the WSDOT Standard Specifications.
Granular Backfill shall meet the gradation
requirements specified in section 9-03.14(1)
of the WSDOT Standard Specifications.
4" minimum diameter slotted
lostic pipe; sloped to drain
(p8"/100' min. slope); provide clean —outs.
Slotted pipe to have 1/8" maximum width
slots.
Cleanouts should be included to allow periodic
maintenance and inspection.
WALL
GRAVEL BACKFILL
FOR DRAINS
DAMP PROOFING
N
1. Wall backrill should consist of well —
graded granular soil with no more than
5R (by wei ht based on the minus 3/4—
inch portionll passing the' No. 200 sieve
(by wet slaving), with no plastic fines.
2. Backfill behind the wall should be
compacted with hand —operated
equipment. Heavy equipment should
not be used as such equipment operated
near the wall could increase lateral earth
pressures and possibly damage the wall.
3. Backfill should be placed in layers not
exceeding 8" loose thickness, and
should be compacted to at least 95R of
the Modified Proctor maximum dry
density (ASTM D1557, Method C
or 0).
4. Drainage gravel beneath floor slab
should be hydraulically connected to a
drainage system. Use of 1" dia. weep
holes located at the downslope side of
the structure is one method.
WALL DRAINAGE AND BACKFILLING
ES RESIDENCE HA m m 7425 O Y MPIIC VIEW DRIVE
EDMONDS, WASHINGTON
:r 4
7.01.03 1 2003-082
' MINIMUM WEIGHT ONOCK
PORTION OF WALL BELOW 6 ft., 2400 lb. 6—MAN ROCK
2 PORTION OF WALL ABOVE 6 ft., 1600 lb. 4—MAN ROCK
MAXIMUM
1
STABLE EXCAVATION SLOPE —
(CONTRACTOR'S RESPONSIBILITY)
COMPACT IN 6" LIFTS WITH MINIMUM OF
4 PASSES BY HAND —OPERATED TAMPER.
COMPACT TO AT LEAST 92% OF MODIFIED
PROCTOR MAXIMUM DRY DENSITY
(ASTM D-1557). BACKFILL SHOULD BE
PLACED AND COMPACTED AS ROCKS ARE
PLACED.
DITCH, SLOPED TO
DRAIN
4" DIAMETER PERFORATED PLASTIC PIPES `
ALL LOOSE SOIL AT ROCKERY FOUNDATION SHOULD BEJ
OVEREXCAVATED AND REPLACED WITH COMPACTED
BACKFILL AS DESCRIBED ABOVE. THE EXCAVATION SHALL
BE KEPT FREE OF WATER. THE PREPARED ROCKERY
FOUNDATION SHOULD BE EVALUATED BY A SOILS ENGINEER
PRIOR TO PLACEMENT OF ROCK.
LEGEND
4 H=10' MAX
12' MIN
H/3 MIN WIDTH
FOR BASE ROCK
NOT TO SCALE
[FOR ILLUSTRATION ONLY. NOT INTENDED FOR CONSTRUCTION]
;!;,l IMPERVIOUS SURFACE LAYER: 6' To 12" COMPACTED SOIL
BACKFlLL: CLEAN, CRUSHED LEDGE ROCK, 2" MAXIMUM SIZE, 40 TO 6O5 GRAVEL.
LESS THAN 5X FINES (PASSING #200 SIEVE). FINES SHALL
BE NON —PLASTIC.
ROCKERY RETAINING WALL
g,►,,(=; I HwAQosQENWWc I CLOBES RESIDENCE
7425 0 YMPIIC VIEW DRIVE
EDMONDS, WASHINGTON
n� 5
7.01.03 1 2003-082
1
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71
J
RELATIVE DENSITY OR C,_,SISTENCY VERSUS SPT N-VALUE
COHESIONLESS SOILS
COHESIVE SOILS
ON"N
(ebweM)
COANstancY
N(MavaM)
APProtlrtuU
Unbaned Shaer
and" %)
Shangth aq
Very Loose
0 to a
0- 15
Vary Solt
0 to 2
e250
Leon
a to 10
15 - 35
Soft
2 to a
250 - wo
Medium Dense
10 b 30
35 - 85
Madw Say
a b 8
No Iwo
Dones
30 to 50
65 - 95
Stdf
a to is
1000 2D00
Very Dense
ever 50
85 - 100
Very Sea
15 b 30
2000 4000
Had
ova30
>8000
USCS SOIL CLASSIFICATION SYSTEM
MAJOR DIVISIONS
GROUP DESCRIPTIONS
Goan
Gravel end
Clean Gravel
.'
GW
Walyredw GRAVEL
Greer
Grayly S045
(aaeerno an")
GP
Paorygndb
Sets
°
GRAVEL
Mara wren
p
50%a cane
Greve adn
°
GM
Say GRAVEL
Fracas, Retained
FNes(=sdable
on No ! Siaw
errlerax or Tres)
GC
Carey GRAVEL
Sand ant
Clow Sam
•••
SW
Wall -graded SAND
Sandy SoN
(altlserro Mea)
,,'•
Mon am
SP
Pooryyrbb SAND
50%Retaned
50%or More
a No.
1dal
.:
SM
Soy SAND
200 Sieve
of Coarse
of Car
(apPredade
F:8-
Paaarp
FrecNo
Sire
$C
claYSY SAND
S Slave
MLm
SILT
Fir
SIN
Uwxd Lima
Grained
eon
Lou men 60%
CL
Lean cur
Sets
Clay
OL
Organc SILTnbgaMc Cur
MH
Elastic SILT
60%a More
Set Liquid Lino
Passing
arw So%or Myer
CH
FatCLAY
ieve No. 200 S
coy
yea
-
OH
OlgaNC SILT/Organic Cur
Highly Organ Solis
-
r r
PT
PEAT
COMPONENT DEFINITIONS
COMPONENT
SIZE RANGE
Bnrmdan
Lager men/2n
Coons
3nr12M
Gravel
3nNNo4(/.51=)
Course gravel
3n to 314n
FM.even
314 In b No 4 p4.5mm1
Sand
No.a (4.5 mm) b Na 200(0.074 min)
Caere east
No. Aµ.S mm) to Nit. 10(2.0MI
Medum abd
Na. 10 (2.0 inn) to No. al (0.42 earl
Fna sad
Nor 40(0.42 mm) b No. 200(0.074 mm)
So ad Clay
- Smaaerawr No. 2D0(0.074nm)
TEST SYMBOLS
%F
Percent Files
AL
Atlaberg Units: - PL- Plastic Unit
LL - Liquid Unit
CBR
California Bow" Ratio
CN
Consolidation
DO
Dry Density (pa)
DS
Direct Shear
GS
Grain Size Distribution
K
Permeability
MD
MastuelDensby Relationship (Procter)
MR
Remillard Modulus
PID
PlatolonlMon Devloe Reading
PP
Packet PensacnMer
APPMX Cantressh'e Strength (tsf)
SG
Speclk Gravity
TC
Triodal Comprossion
TV
Torvao,
Apgox Shear Strength (tsf)
UC
Unconlined Canprosslon
SAMPLE TYPE SYMBOLS
®2.0. OD Split Spoon (SPT)
I(140 lo. hainrrar With 30 n. drop)
SWby Tube
3.1)e" OD Split Spoon with Srass Rings
OSmall Bag Sample
Large Bag (Bulk) Sample
Core Run
Non-stentlard Penetration Teel
(3.0` OD spit Spoon)
GROUNDWATER SYMBOLS
$- Groundwater Lem (meaxmad at
done of drilling)
Groundwater Level (measured In wed or
open hole abr water Neel stabilized)
COMPONENT PROPORTIONS
PROPORTION RANGE
DESCRIPTIVE TERMS
<5%
Clean
5 -12%
Slightly (Clayey, Slay, Sally)
12.30%
Clayey. Silly, Bandy, Gmrolty
30 -50%
Very (Clayey. Sim, Sealy, Gravelly)
ConPorents are emerged in order of Inerming quaaities.
NOTES: Sail daui0ations Presented on exploration logs a s based on visual and laboratory observation.
Set desonpticns ore peeented In the failolving general order.
Densibybo reeNncy, color, modhIrIV A00 GROUP NAME, ad6dona aOrouP name (eeroj, masare
cart" Pnpwan,pWaBon,erd argaedryacon+bTanb, mdd'tlondcommantr.
(GEOLOGIC INTERPRETATION)
Please refer to 111a discussion In the report had as well 08 0r exploration logs for a more
compete desaiplion of subsurface conditions.
Y lii A I
HWAGEOSCIENCES INC
Clobes Residence
7425 Olympic View Drive
Edmonds, Washington
MOISTURE CONTENT
DRY Absence ofn isbu%dusty,
dry to tlr buds.
MOIST Damp but no vmle weer.
WET Viable ameweter, uauaY
as N below wan babe
LEGEND OF TERMS AND
SYMBOLS USED ON
EXPLORATION LOGS
PROJECT NO.: 2003082 FIGURE: A-1
LEGEND MGG82.GPJ 71=3
SM
Very loose to loose, dark brown, silty, fine SAND, moist
Abundant rootlets and organics.
[TOPSOILIDUFF]
SP
Loose, light brown, slightly silty, slightly fine to coarse
.:.
SM
gravely, fine SAND, moist. Rootlets rated.
Medium dense, brown, slightlyfine to coarse grevelly, fine to
. SP
medium SAND, moist
Total depth with hand auger "a 4 feet due to soil caving
below this depth.
� iT BORING:
, Clobes Residence HH BORING:=1
:: 1 7425 Olympic View Drive
IMGEMENCESINC Edmonds, Washington PACE`' of f
i' PROJECT NO.: 2003082 FIGURE: A-2
BORING WITH OTHER PENETRATION TESTS 2003082.GPJ 7r=3
DRILLING COMPANY: HWA GeoScienees, Inr SURFACE ELEVATION: 313.00 * feet TE STARTED: W21U = 1
DRILLING METHOD: Hand Auger/DCP '%.,.i'E COMPLETED: 6/20/2003
SAMPLING METHOD: Grab samples LOGGED BY: B. Hawkins
' LOCATION: See Figure, 2 _
♦ Non-standard Penekalun Resistance ( Mows iwrfW )
m W 117 Is. weight, 25- drop)
Lu
e WWJ W W
N S 6 W H
W
DESCRIPTION r�/t a' G 0 10 20 30 40 50 01
0 SM Loose, dark brown, silty, fine SAND, molst Abundant 0
organics/rootlets.
O F
SP
. Loose to very loose, brown. fine SAND, moist
....: .:....:....:.........i....:.... r....i....
J :
At depth of 22 inches, DCP sunk 69 Inches for 1 blow. Very
loose adl. Able to push hand auger through this zone
' without turning auger.
Total hand auger depth was 3.5 feel due to soil caving
below this depth.
....:.....
I
5 ...................:....:....: 5
....:....i.... i.........:
.... i.... i....i.... i....i
DCP depth : 8.18 feel
No water encountered. DCP nods were dry.
10 10
0 20 40 60 80 100
Water Content (%)
Plastic Limit 1----♦—{ Liquid Limit
Natural Water Content
' NOTE: This log of subsurface conditions applies orgy at the specified location and on the dale Indicated
and therefore may not necessady be Indicative of other times and/or locations.
Clobes Residence HH BORING:
ORING:-2
7425 Olympic View Drive
FiWAaosaENCES INC Edmonds, Washington PAGE: 1 of 1
'-PROJECT NO.: 2003082 FIGURE- A-3
BORING WITH OTHER PENETRATION TESTS 2003082.GPJ 7/3103
.
SM
Loose, blown, ally. fine SAND, moist Organicstrootlets
Anoted.
rTOPSOILMUFFI
'.
Sp
Loose. Mown, 9NNy fine to coarse gravelly. fine SAND.
moist Rootlets noted.
a
GP
Loose, Bendy, fine to coarse GRAVEL, moist
Total hand super depth roes 2 feet due to gravel roving
' Clobes Residence BORING:
HH-3/DCP-3
7425 Olympic View Drive
MAGEOSaENCES INC Edmonds, Washington PAGE: I of f
PROJECT NO.: 2003082 FIGURE: A-4
BORING WITH OTHER PENETRATION TESTS 2DO3082.GPJ 7rM3
1
i
1
1
1
1
1
1
i
1
SM
Loose, dark brown, silty, fine SAND, mist Abundant
organiestrootlets.
(TOPSOIL/DUFF]
-. SP
Loose, brown, slightly fine to coarse gravelly, Me SAND, .
Roolletsforoanics noted.
Total hand auger depth was 1 foot due to loose gravels
caving below this depth.
1 R,BORING:
, Globes Residence
V �' 7425 Olympic View Drive HH-4/DCP-4
HMGEOZENCES INC Edmonds, Washington PAGE: 1 of 1
1 PROJECT NO.: 2003082 FIGURE' A-5
BORING WITH OTHER PENETRATION TESTS 2D03082.GPJ MUM
----------
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NTWAI Group Northwest, Inc. °�"'"Envio;nenel�:Mil�
September 25, 2003
Ms. Star Campbell
Development Services Department
Planning Division
121 - 5th Avenue North
Edmonds, Washington 98020
Subject: Geotechnical Peer Review Addendum
Clobes Residence Addition
7425 Olympic View Drive
Edmonds, Washington
Reference: HWA Geosciences, Inc. Project No. 2003082-21
Geotechnical Report dated July 3, 2003
Dear Ms. Campbell:
' "''-CPE JVZC G-1697
Sf P Z 6 ?083
R ftft KEPT
We had reviewed the referenced HWA Geosciences, Inc. (HWA) report and prepared
peer review comments in a letter dated September 9, 2003 for the Clobes residence
addition. At your request, we are providing additional comments regarding the steep
slope exemption information contained in the HWA report.
The slopes at the project site as defined by the Edmonds Community Development
Code (ECDC) are classified as steep slopes hazard areas, since the slopes average 46
percent for a total elevation change of approximately 25 feet.
A. Site Standards
1) The site will be stable after the permitted activity.
2) The slope is mapped as advance outwash.
3) Fill placement recommendations are. contained in the HWA report.
13240 NE 20th Street, Suite 12 • Belleuve, Washington 98005
Phone 425/549-8757 • FAX 425/549-8758 ATTACHMENT 4
September 25, 2003
Peer Review - Steep Slope Exemption
G-1697
Page 2
4) Impermeable soils interbedded with granular soils, springs, groundwater
seepage, previous landsliding or slide debris are not present at the site.
5) Depth of loose soils on the slope is 1 to 7 feet, which exceeds the 3 foot site
standard criteria.
B. Development Characteristics
1) The HWA report Figure 3 - Cross Section A -A' shows the 35 percent slope
excavation line extending from the edge of the exception zone.
2) Retaining structures on the slope or rockeries have been addressed in the HWA
report.
3) A buffer of 15 feet can be kept free from commercial development to property
lines of adjacent residential properties, however, this buffer has been previously
disturbed, and it will be disturbed again by following the 35 percent excavation
line recommended in the ECDC.
4) The proposed development will not decrease the stability of any adjacent
property.
From the above review, we conclude that the HWA report generally satisfies the City of
Edmonds Steep Slope Exemption criteria for the subject project, with the following
exceptions:
a) Depth of loose soils on the slope.
b) The proposed 35 percent excavation line extends into the Exception zone.
c) The 15 foot buffer has been disturbed in the past and will be disturbed again.
It is our professional opinion that the above exceptions do not decrease the stability of
the proposed development or the adjacent property if the project is developed under
proper engineering supervision.
We conclude that the HWA report addresses the steep slope exemption criteria
although it is not done in an explicit manner for all of the items listed in the Steep Slope
Exemption Handout.
Geo Group Northwest, Inc.
September 25, 2003 G-1697
Peer Review - Steep Slope Exemption Page 3
If you have any questions regarding this addendum letter, please call.
Sincerely,
Geo Group Northwest, Inc.
William Chang, P.E.
Principal
Geo Group Northwest, Inc.
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FILE NO.: SD-03-115 & ADU-03-119
APPLICANT: Clobes
NOTICE OF APPLICATION
AFFIDAVIT OF POSTING
STATE OF WASHINGTON)
COUNTY OF SNOHOMISH)
1, Steve Bullock, first duly sworn, on oath, depose and say:
That on the 22nd day of August 2003, the attached Notice of Application was posted
as prescribed by Ordinance, and in any event, in the Civic Center and the Library,
and where applicable on or near the subject pr9perty. ,
Subscribed and sworn to before me this oIX W day of_ V142 j
CONSTANCE M. CURTIS
NOTARY PUBLIC STATE OF WASHINGTON Notary Public in and for the State of Washington.
COMMISSION EXPIRES
APRIL 9 2007 Residing at 'l
1%.
File Number: SD-03-115 & ADU-03-119
Applicant: Clobes
NOTICE OF DEVELOPMENT APPLICATION
AFFIDAVIT OF MAILING
STATE OF WASHINGTON)
COUNTY OF SNOHOMISH)
I, Diane M. Cunningham, first duly sworn, on oath, depose and say:
That on the 22nd day of August 2003, the attached Notice of Development
Application was mailed as required to adjacent property owners, the names of which
were provided by the applicant.
Signed IU 1uu'vC— m _ C,C,I,u "
Subscribed and sworn to before me this Vb day of .
E
ANCE M. CURTIS `vRY PUBLIC Notary Public in and for the State of Washington.
0 WASHINGTONSSION EXPIRESl r"/,�RIL9 I I Residing at !�
Ita✓
N%Wl`
ADJACENT PROPERTY OWNERS LIST
Attach this notarized declaration to the adjacent property owners list.
On my oath, I certify that the names and addresses provided represent all properties
located within 300 feet of the subject property.
Signature of Applicant or
Subscribed and sworn to before me this
Residing at / C—
O day of
C.
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AP0.doc1L:\Templf0rms
Mark Yeadon
Edward Mcmackin
Jack &Sharon Miller
'7505 184th PI SW
18328 Homeview Dr
18404 Homeview Dr
Edmonds; WA 98026
Edmonds, WA 98026
Edmonds, WA 98026
Samuel Lee
Jeffrey Butler
Samuel & Cynthia Lee
7512184th Pl SW
19119 N Creek Pkwy#113
7512184th PI SW
Edmonds, WA 98026
Bothell, WA 98011
Edmonds, WA 98026
Vernon Edwin Williams
George Jensen
Paul & Amy Tomlin
7520184th PI SW
7517 Olympic View Dr
7530184th PI SW
Edmonds, WA 98026
Edmonds, WA 98026
Edmonds, WA 98026
Scott & Karen Hibbert
Gary & Terrie Gerber
Donald Johnson
18420 Homeview Dr
18421 Homeview Dr
18427 Homeview Dr
Edmonds, WA 98026
Edmonds, WA 98026
Edmonds, WA 98026
Mary Lou Vigil
Marvin & Brenda Jones
Matthew & Susan Wood
18428 74th PI W
18432 74th PI W
7333 Olympic View Dr
Edmonds, WA 98026
Edmonds, WA 98026
Edmonds, WA 98026
Andre & Carolyn Belyea
Charles Taylor
Snohomish Co Property Mgmt
7327 Olympic View Dr
18429 74th PI W
3000 Rockefeller Ave #M 40
Edmonds, WA 98026
Edmonds, WA 98026
Everett, WA 98201
Keith & Sherrelle Collingridge
Rudolph & Barbara Julian
Richard & Jeanne Sherwood
18423 74th PI W
18417 74th PI W
1841174th PI W
Edmonds, WA 99026
Edmonds, WA 98026
Edmonds, WA 98026
Donald & Lois Schatz
Jong Chung
Charles & Marlene Belt
18403 74th PI W
18325 Homeview Dr
18401 Homeview Dr
Edmonds, WA 98026
Edmonds, WA 98026
Edmonds, WA 98026
I,
City Of Lynnw d
Lynnwood City Of
William & Kathleen Massey
PO Box 5
PO Box 5008
PO Box 399
Lynnw WA 98046
Lynnwood, WA 98046
Oak Harbor, WA 98277
Paul Stromme
9623 Ave.
Dave &Julie Clotles
Seattlee,, WA 98115
7425 Olympic View Dr.
Edmonds, WA 98026
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city of edmonds
land use application
0 ARCHITECTURAL DESIGN REVIEW FOR OFFICIAL USE ONLY
0 COMPREHENSIVE PLAN AMENDMENT
0 CONDITIONAL USE PERMIT FILE# �j�,b3-16 ZONE P15>+ ia-
0 HOME OCCUPATION DATE I7 03 REC'D BY Q�C,
0 FORMAL SUBDIVISION FEE ^7 1 MCEIPT# &at,:�,Z-7
e SHORT SUBDIVISION ��
0 LOT LINE ADJUSTMENT HEARING DATE
e PLANNED RESIDENTIAL DEVELOPMENT a HE 0 STAFF a PB 0 ADB 0 CC.
e OFFICIAL STREET MAP AMENDMENT
0 STREET VACATION
e REZONE CA ' ()3 _A.3
e SHORELINE PERMIT
0 VARIANCE / REASONABLE USE EXCEPTION
0 OTHER: cis mGi, 4'Xga..ls9 Op
PROPERTY ADDRESS OR LOCATION T
PROJECT NAME (IF APPLICABLE)'
PROP ERTYOWNE&-iZf--f J6L/�-- nPHONE i 1*5-?1.
ADDRESS
E-MAIL ADDRESS FAX #
TAX ACCOUNT # 4n1 fP DC 'D53 MOD SEC. TWP. RNG.
DESCRIPTION OF PROJECT OR PROPOSED USE
e:::) $g
APPLICANT PHONE #
ADDRESS
E-MAIL ADDRESS / FAX # /'^� /�--
CONTACT PERSON/AGENT /�L. c �T�OJ� PHONE Z,2e-�0 EO� -73 ?�
ADDRESS
F-MAIL ADDRESS FAX #
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 file this applicationonthe behalf of the owner as listed below.
SIGNATURE OF APPLICANVAGENT A�,,�' �— = DATE l�
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 of inspection and posting attendant
to this application.
SIGNATURE OF OWNER GzaC,E ,' 4 1 DATE
This application form was revised on 1127/00. To verify whether it is still current, call (425) 771-0220.
L:\LIBRARYIPLANNING\Forms & HandoutsNPublic HandoutsVand Use Applicatim.doc
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,1.0
city of edmonds
land use application
0 ARCHITECTURAL DESIGN REVIEW FOR OFFICIAL USE ONLY
0 COMPREHENSIVE PLAN AMENDMENT FILE # ?AN6
0 CONDITIONALUSEPERMiT
0 HOME OCCUPATION, DATE REC'D BY
0 FORMAL SUBDIVISION FEE RECEIPT #
e SHORT SUBDIVISION
0 LOT LINE ADJUSTMENT HEARING DATE
- ------------
0 PLANNED RESIDENTIAL DEVELOPMENT 8 HE 0 STAFF 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�-
PROJECTNAME(IF,A.��PPLICABLE)
PROPERTY OWNERUA� e 9`�� /� ��hP� PHONE k'�gn 77 s 9l TL
ADDRESS
E-MAIL ADDRESS r FAX #
TAX ACCOUNT # SEC. TWP. RNG.
DESCRIPTION OF PROJECT OR PROPOSED USE
4.z 42 c1 i .o e)1�
APPLICANTPHONE #
ADDRESS
E-MAIL ADDRESS // FAX #
CONTACT PERSON/AGENT 10�1/ —T�O/� PHONE #L20 �`0-73 7B
ADDRESS *ba3 �� Ak,12'' Al
E-MAIL ADDRESS _ FAX #
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 famished 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 file this
�application
noon the behalf of the owner as listed below.
SIGNATURE OF APPLICANT/AGENT/�1 �_� > DATE`_=yL
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 of inspec I and posting to dart to this application. �7 /
SIGNATURE OFOWNE DATE `( /� B�
This application form was revised on 1/27/00. To verify whether it is still current, call (425) 771-0220.
L:V-®RARY\PLANNINGTomn A li ndmtsTublic HendoutsVmd Use AppliadonAm