16001 73RD PL W.PDFIIIIIIIIIIII
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16001 73RD PL W
TAX ACCOUNT/PARCEL NUMBER:
BUILDING PERMIT (NEW STRUCTURE):
COVENANTS (RECORDED) FOR:
CRITICAL AREAS VO4 G DETERMINATION: ❑ Conditional Waiver Xstudy Required ❑ Waiver
DISCRETIONARY PERMIT #'S:
DRAINAGE PLAN DATED:
PARKING AGREEMENTS DATED:
EASEMENT(S) RECORDED FOR:
PERMITS (
PLANNING DATA CHECKLIST DATED:
SCALED PLOT PLAN DATED:
SEWER LID FEE $:
SHORT PLAT FILE:
SIDE SEWER AS BUILT DATED:
SIDE SEWER PERMITS) #:
GEOTECH REPORT DATED:
STREET USE / ENCROACHMENT PERMIT #:
WATER METER TAP CARD DATED:
IQRIES
LOT: BLOCK:
LATEMP\DSTs\Fornu\.Street File Checklist.doc
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Critical Areas Checklist
CA File No:.CVhU0ft,0L"
Site Information (soils/topography/hydrology/vegetation)
1. Site Address/Location /G 0a / /mil Cv , of ,,ovx�c_a &,.ft- 9 €3 0
2. Property Tax Account Number: . 0 a 7 Po yap o ra c "
3. Approximate Site Size (acres or square feet): / .aer-r_
4. Is this site.currently developed? -- yes; no.
If yes; how is site developed?
5. Describe the general site topography. Check all that apply.
Flat: less than 5-feet elevation change over entire site.
Rolling: slopes on site generally less t im—n 15% (a vertical rise of 10-feet over a horizontal
distance of 66-feet).
Hilly: slopes present on site of more than 15% and less than 30% (a vertical rise of 10-feet
over. a Horizontal distance of 33 to 66-feet).
Steep: grades of greater than 30% present on site (a vertical rise of 10-feet over a horizontal
distance of less than 33-feet).
Other (please describe):
6. Site contains areas of year-round standing water: "�46 ; Approx. Depth:
7. Site contains areas of seasonal standing water: ; Approx. Depth: _
What season(s) of the year?
8. Site is in the floodway floodplain of a water course. Na
9. Site contains a creek or an area where water flows across the grounds surface? Flows are year-round?
Flows are seasonal? (What time of year? ).
10. Site is primarily: forested ; meadow ;shrubs ; mixed
urban landscaped (lawn, shrubs etc)
11. Obvious wetland is present on site:
For City Staff Use Only 507
1. Plan Check Number, if applicable?
2. Site is Zoned? P2 n - 19 89 - 1
3. SCS mapped soil type(s)? 4 -
4. Critical Areas inventory or C.A. map indicates Critical Area on site? `!ii - Qrtm ,,:, }„ ('-t'-' k A4 we-e!L,,�
W^U At A-,-,� ; E-r- hx ;?,,A Ape,, si, f^ a 1;1 q 1;k , 1, b,�. G�suv<r.� g� C.
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5. Site within designated earth subsidence landslide hazard area?
DETERMINATION
(_STUDY REQUIRED WAIVER
Reviewed by: __ � Aze- , Date: It // 3 /mac
`QC. 1 %91
#rzu
City. of?dmonds
Development Services Department
Planning Division
Phone: 425.771.0220
Fax: 425.771.0221
The Critical Areas Checklist contained on this form is to
be filled out by any person preparing a Development
Permit Application. for the City of Edmonds prior to
his/her submittal of the application to the City.
The purpose of the Checklist is to enable City staff to
determine whether any potential Critical Areas are, or
may be, present on the subject property. The information
needed to complete the Chec d'is. should be easily
available from observations of the site or data available at
City Hall (Critical areas inventories, maps, or soil
surveys).
Date Received: i 0 1 .2 ;b 1 2 C> L) 40
City Receipt #: 042q 4 7i
Critical Areas File #:_CA" . I pQ . Q LL
Critical Areas Checklist Fee: $135.00'
Date Mailed to Applicant:—] t - \ 4 - zcxy,
A property owner, or his/her authorized representative,
must fill out the checklist, sign and date it, and submit it
to the City. The City will review the checklist, make a
precursory site visit, and make a determination of the
subsequent steps necessary to complete a development
permit application.
Please submit a vicinity map, along with the signed copy
of this form to assist City staff in fmaing and locating the
specific piece of property described on this form. In
addition, the applicant. shall include other pertinent
information (e.g. site plan, topography map, etc.) or
studies in conjunction with this Checklist to assistant staff
in completing their preliminary assessment of the site.
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 application on the behalf of the owner as listed below.
SIGNATURE of APPLICANT/AGENT i&, ,_.- iS DATE 9 �,x s /0c
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 official and the staff of the City of Edmonds to enter the subject property for the
purposes of inspection anposting attet tokplication.
SIGPIATUP.E OF flwI3ER� DATE. 1 U� \ D�
PLEASE PRINT CLEARLY
Owner/Applicant:
Name
72 `/ Z Os CCh oc-3 P1
Street Address
Sir k/3ci-k c t_e. e A►- 93 �c�t` .
Applicant Representative:
13rIte&& _ Is c sow
Name
Street Address
EcY.hc;>, d s , C-� .4 9 8 o�G
City State Zip City State Zip
Telephone: Telephone: "VA-3 - 5-:X1 - /.S--r-5;
Email address (optional):
-514-S Q-n.V 4.. C/i C. pA�.
Email Address (optional):
0
CITY OF EDMONDS 0
CRITICAL AREAS RECONNAISSANCE REPORT
Site Location: 16001 - 73`d Avenue W. Tax Acct. Number: 00790400000100
Determination: Study Required Determination #: CRA20060149
Applicant: Brian Isaacson Owner: Dennis Chiavelli
CRITICAL AREAS RECONNAISSANCE REPORT: STUDY REQUIRED
During review and inspection of the subject site, it was found that the site may contain critical
areas, including Areas with Potential Wetlands, Landslide Hazard Area, Erosion Hazard Areas,
and Fish and Wildlife Habitat Conservation Areas pursuant to Chapter 23.40 of the Edmonds
Community Development Code (ECDC).
GENERAL CRITICAL AREAS REPORT REQUIREMENTS
Critical Areas Reports identify, classify and delineate any areas on or adjacent to the subject
property that may qualify as critical areas. They also assess these areas and identify any
potential impacts resulting from your specific development proposal. If a specific development
proposal results in an alteration to a critical area the critical areas report will also contain a
mitigation plan. You have the option of completing the portion of the study that classifies and
delineates the critical areas and waiting until you have a specific development proposal to
complete the study. You may also choose submit the entire study with your specific
development application.
Please review the minimum report requirements for all types of Critical Areas which are
listed in ECDC 23.40.090.D. There are additional report requirements for different types
of critical areas (see below).
Note that it is important for the report to be prepared by a qualified professional as
defined in the ordinance. There are options on how to complete a critical areas study
and an approved list of consultants that you may choose from. You may contact the
Planning Division for more information.
General Mitigation Requirements for all Critical Areas are discussed in ECDC 23.40.110
through 23.40.140.
REPORT REQUIREMENTS — WETLANDS
The site investigation has shown that the site may contain or be adjacent to a wetland.
Wetlands are areas inundated or saturated by ground or surface water that support, under
normal circumstances, vegetation adapted for life in saturated soil.
• Wetlands are generally rated according to their size, condition, function, and vegetation
types into four (4) different categories described in ECDC 23.50.010 and by use of the
"City of Edmonds Wetland Field Data Form" by the critical areas consultant.
• Buffer widths for wetlands vary depending on the category of the wetland as listed in
ECDC 23.50.040.F.
• In addition to the general requirements for Critical Areas reports referenced above,
there are specific Critical Areas report requirements for wetlands that are provided in
ECDC 23.50.030.
PROPOSPS ASSOCIATED WITH WETLAND
Development proposals that encroach into wetlands or their buffers or building setbacks may be
allowed through the approval of certain processes.
• The width of a wetland buffer may be reduced through buffer enhancement if the
criteria described in ECDC 23.50.040.F.3 can be met. The maximum amount that a
buffer can be reduced through buffer enhancement is 50%.
• A buffer may also be modified through a process called buffer averaging. The criteria
applied to buffer averaging are listed in ECDC 23.50.040.F.4. The maximum amount
that the buffer width can be reduced at any single location through buffer averaging is
50%.
• Development proposals that proposed encroachments into buffers beyond what is
allowed through the above methods require a Critical Areas Variance, or a Reasonable
Use Exception. If you think that you have a proposal that may require one of these
processes, please contact a Planner for more information.
• Any time a development proposal requires an alteration to a wetland, a mitigation plan
is required as part of the Critical Areas report. In addition to the General Mitigation
requirements referenced above, mitigation requirements specific to wetlands are
provided in ECDC 23.50.050.
• NOTE: There are specific performance standards for the subdivision of lands in
wetlands and wetland buffers. These are listed in ECDC 23.50.060.
STUDY REQUIREMENT — EROSION HAZARD AREA
It appears that this property contains or is adjacent to an Erosion Hazard Area.
• Erosion Hazard areas include Alderwood and Everett series soils on slopes of 15
percent or greater. among others.
• Landslide Hazard Areas are further defined in ECDC 23.80.020.A.
• In addition to the general requirements for Critical Areas reports referenced above,
specific Critical Area report requirements for Erosion Hazard Areas (which are one of
the Geologically Hazardous Areas) are provided in ECDC 23.80.050.
• Note that Stable Erosion Hazard Areas may have limited report requirements at the
director's discretion. At a minimum an erosion and sediment control plan prepared in
compliance with the requirements in ECDC Chapter 18.30 shall be required.
DEVELOPMENT PROPOSALS ASSOCIATED WITH EROSION HAZARD AREAS
Development is restricted within an Erosion Hazard Area.
• Projects that will intrude into these areas will require a report by a licensed Geotechnical
Engineer or other qualified professional.
• Development standards are given in ECDC 23.80.060 and 23.80.070.
STUDY REQUIREMENT — LANDSLIDE HAZARD AREA
It appears that this property contains or is adjacent to a Landslide Hazard Area.
• A Landslide Hazard Area is any area with a slope of forty percent (40%) or steeper and
with a vertical relief of ten (10) or more feet (except areas composed of consolidated
bedrock).
• Landslide Hazard Areas are further defined and illustrated in ECDC 23.80.020.B.
• In addition to the general requirements for Critical Areas reports referenced above,
specific Critical Area report requirements for Landslide Hazard Areas are provided in
ECDC 23.80.050.
2
DEVELOPMENT PROP�ALS ASSOCIATED WITH LANDS&E HAZARD AREAS
Development is restricted within a Landslide Hazard Area and its buffer.
• Projects that will intrude into these areas will require a report by a licensed Geotechnical
Engineer.
• The criteria that are applied depend on the amount that the buffer is reduced.
• The buffer can be reduced to a minimum of ten (10) feet (with an additional 15' building
setback per ECDC 23.40.280) if a report is prepared that meets the standards listed in
ECDC 23.80.050. The alteration must also meet the requirements listed ECDC
23.80.060.
• In addition, proposals to reduce the buffer to less than ten (10) feet must comply with
the design standards listed in ECDC 23.80.070.A.3.
STUDY REQUIREMENT — FISH AND WILDLIFE HABITAT CONSERVATION AREAS
Since the site is within a mapped fish and wildlife habitat conservation area, the City
would like to preserve as much of the native vegetation as possible.
DEVELOPMENT PROPOSALS ON A SITE WITH FISH AND WILDLIFE HABITAT
CONSERVATION AREAS
The applicant must submit a clearing/tree cutting plan with any development permit.
Tree cutting and clearing of native vegetation shall be limited to the footprint of
development.
ALLOWED ACTIVITIES
Certain activities are allowed in or near critical area buffers as specified in ECDC
23.40.20. If you have any questions about whether your proposed development
qualifies as an allowed activity, please contact a Planner for more information.
EXEMPT DEVELOPMENT PROPOSALS
Certain development proposals may be exempt from Critical Areas Requirements
(ECDC 23.40.230). If you think that a specific development proposal may be exempt,
contact a Planner for more information.
Mea Gruwell
Name ! ig4ture Date
NOTE: Cited sections of the Edmonds Community Development Code (ECDC) can be found on
the City of Edmonds website at www.ci.edmonds.wa.us.
3
fn C. 18911
CITY OF EDMONDS
ST RE, ETY TmU ON
MAYOR
121 5TH AVENUE NORTH • EDMONDS, WA 98020 • (425) 771-0220 • FAX (425) 771-0221
Website: wwwxi.edmonds.wa.us
DEVELOPMENT SERVICES DEPARTMENT
Planning • Building • Engineering
September 25, 2003
Ms. JoAnn M. Anderson
614 Daniels Drive
East Wenatchee, Washington 98862-4036
Dear Ms. Anderson:
In response to a recent localized slide, City officials conducted a site inspection on September 16,
2003 and observed slide damage to have occurred all on private property west of Sequoia Ridge
Lot 4, at or near Tract A and Lot 2 property in the plat of Lorian Woods. Accompanying City
officials was a representative of Landau Associates, the City's professional geotechnical
consultant.
Landau Associates conducted a site reconnaissance and subsequently prepared a report (copy
enclosed) that describes the observed slide. Note, the report suggests that there is low probability
of immediate risk from the slide damage particularly because the downslope private properties
are currently undeveloped. The report recommends that property owners in the vicinity of the
landslide be alerted to the condition of the slope. The purpose of this letter and the attached copy
of the Landau Associates report is to notify you and other private property owners in the area, of
the current situation as we know it, so that you may take whatever action you deem appropriate.
Since you may be unaware of this condition, the City recommends that you visit the site with a
professional Geotechnical Engineer for an independent assessment of your private property to
provide recommendations about the impacts of possible future landsliding, preventative
measures to property your property and any possible site restoration that may be adviseable for
you to undertake to protect your property. Geotechnical reports and assessments for properties
within the area are on file at my office and are available for review.
If your geotechnical engineer requires restoration or slope mitigation/improvements an approved
permit from the City is required since all work must comply to City Ordinance #2661 which
regulates the Meadowdale Earth Subsidence Landslide Hazard Area.
Incorporated August 11, 1890 •_0:z .,
Si�tvr Cite - Hakinan .lanan
Ms. Anderson
Page Two
September 25, 2003
Please contact me should you have any questions regarding permit requirements or other
concerns at 425-771-0220 extension 1226.
Sincerely,
Jeannine L. Graf
Building Official, C.B.O.
Cc: Duane Bowman, Development Services Director
Dave Gebert, City Engineer
`0 12 5 ?12 6403 L k N 0 ASSO1 TES II!C uS/2)/H 14:II r.uul uul
LANDAU
,ASSOCIATES
September 25, 2003
City of Edmonds, DevclopmLnt Services Department
121 511 Avenue North
Edmonds, Washington 98020
Attn: Mr. Don Fiene and Ms. Jeannine Graf
RE: LANDSUIDE EVAIVATION
MEADOWDALF, AREA - LOR1L4N Wo()DS/SEQUOIA RIDGE PLATS
)E;DMONDS, 'WASH INGTON
Dear Mr. Fiene and Ms. Graf
This letter summarizes our observations and recommendations related to a landslide that occurred
on the steep slope, east of 73rd Place West, in the northeastern part of the Lorian Woods plat, extending
upslope to the western edge of the Sequoia Ridge Plat. At the request of the City of Edmonds (City),
Deborah Ladd of Landau Associates visited the site on September 16, 2003 along with City of Edmonds
personnel Dave Gebert, Don Fiene, Jeannine Graf, Ann Bulbs, Noel Miller, and Jim Kammerer. The
purpose of our visit was to assess site conditions and identify any immin"t hazard to City -owned
facilities and the general public from the observed slide. As part of our visit, we also observed surface
conditions on the ridge near the top of the slide. Our services were provided under Task Order No. 22 of
our on -call Geotecluucal Engineering Services Agreement with the City.
BACKGROUND AND OBSERVATIONS
The landslide is located in the northeast part of the Lorian Woods plat, east of Lorian Woods Lot
2 and west of Lot 4 in the Sequoia Ridge plat. The landslide lies north of the City's interceptor drainage
system "lA" and immediately north. of catch basins CB #6 and CB 48 in this system. The landslide
extends west to near (or onto) Lot 2 (16007 73'd Place West) in the Lorian Woods plat.
We understand that the landslide occurred sometime late on September 15 or early on September
16, 2003. At the time of our visit, we accessed parts of the slide area using the path used for monitoring .
the interceptor drainage system. The ground surface on the path was slightly moist, but soils beneath a
thin surficial layer were near dry. Areas of wet soil and seepage were observed near the path in areas
where year-round seepage is typically present. Heavy rainfall was reported the night of September 15,
2003 by Edmond's residents. Overall rainfall for the weeks preceding the slide has been relatively lows.
ENVIRONMENTAL I GEOTECHNICAL I NATURAL RESOURCES
1302nd Avenue South - Edmonds, WA 98026 - (425) 718 C907 - fax (Q'S) 175-Wyi - w w.landaulncxom
SEArTLE - SPOKANE - TACOMA - PORTLAND
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The landslide has combined block sliding and mudflow charactcrist:ics, with an estimated width
of about 20 to 30 ft and a total length of 80 ft or greater. The landslide initiated near the top of the bluff,
apparently from Lot 4, Sequoia Ridge. The slide initiation is about 20 to 40 R (vertical) above the City's
interceptor drainage system IA, CB #8 and about 20 R north of this catch basin. The landslide debris
extended about 10 to 20 ft below (west) of CB #6. The estimated elevation of the top of the slide is at
about 210 to 220 ft elevation. Several seepage zones could be seen in the exposed bluff in the slide area.
The failed soil zone is estimated to be about 3 to 5 ft thick (measured perpendicular to the slope face).
Below the landslide scarp (at the top of the slide), the landslide appears to involve the surficial
layer of soil on the slope along with small to large -sized trees and other surficial vegetation. The
mudflow and vegetative material is currently resting on the slope in the area near catch basins CB #6 and
CB 48. The landslide occurred on private property, did not extend to public facilities other than near the
City's interceptor drainage system, and did not impact any residences.
Soils exposed near the top of the slide area appear to be of glacial origin and consist of outwash
sand and gravel overlying fine-grained, silty and clayey deposits. These conditions are similar to soils
exposed in other parts of the Meadowdale area at similar elevations and are similar to conditions observed
at other slides in the Lorian Woods/Sequoia Ridge area. The exposed soil after sliding was standing near
vertical with a small, shallow, bench visible about 20 ft below the slide scarp. At the time of our visit,
defined seepage paths had not yet developed and seepage was observed generally flowing around the mud
and debris accumulation at the base of the slide zone.
CAUSE OF SLIDING
The bluff in the Meadowdale area is a known landslide hazard zone_ The observed landslide is
consistent with other naturally -occurring landslides along the Meadowdale bluff. Most landslides occur
during or following an intense rainfall.event during the wet winter season. The observed landslide
occurred during or after a short.period of intense rainfall, but not during a period of extended wet weather
such as typically occurs during the winter.. It is possible that the very dry 2003 summer has led to ground
cracking that contributed to the landslide occurrence at this time.
It is our opinion that the landslide originated in native granular soil above a seepage zone on the
steep part of the upper slope. The specific triggering event of the observed landsliding is not ]mown. ft is
Landau Associates' opinion that the landsliding was caused by a combination of infiltration from a heavy
rainfall on the evening and early morning of September 15 and 16, 2003 combined with naturally
occuning seepage near the contact between granular sand and gravel deposits and underlying fine-grained
09.Q5103 11Edrrras%wpr=607,1114V-ori.2n Wood: Sept 2003 9rde rev 2.doC 2 LANDAu AssoclATEs
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deposits. Both heavy rainfall events and groundwater seepage are common contributing factors to slope
failures in the Meadowdale area and throughout Puget Sound.
The observed landslide was likely caused by natural groundwater seepage zones that are present
in the steep portions of the slope. The lowest seepage zones observed during our visit were an estimated
20 ft above the nearest catch basin, CB #8, in the City's interceptor drainage systetn. As discussed in
Landau Associates' Drainage Evaluation Lorian Woods/Meadowdale Area report (July 25, 2002), the
City's interceptor drainage systems capture some of the localized surface water that would otherwise
infiltrate the ground surface below the drainage system. The interceptor drainage systems do not reduce
groundwater levels in the slopes above the systems or reduce seepage from these areas. Accordingly, it is
our opinion that the observed landslide was not caused by or related to the City's interceptor drainage
system.
RISK TO CITY OF EDMONDS FACILITIES OR STRUCTURES FROM OBSERVED SLIDE
No damage was observed in the existing system lA from the September 2003 landslide. The
existing landslide does not appear to pose an immediate risk to any other City -owned facilities. However,
there is a large accunntlation of very soft and wet soil in the lower part of this landslide. This soil could
move further downhill if it becomes wetter due to surface water runon or precipitation. However, due to
the presence of relatively heavy vegetation in the area, downslope movement is crpected to be limited.
BLUFF CRACKING - SEQUOIA RIDGE PLAT
During the site visit, conditions at the top of the bluff above and near the slide were observed.
Observations were conducted of the area near the bluff top on the south and west part of Sequoia Ridge
Lot 4 and along all of the west edge of Sequoia Ridge Lot 3. No cracks were visible on the ground
surface on Lot 4 above the recent slide. Howevcr, observations of the ground surface directly above the
recent slide area (e.g., within the zone about 3 to 10 A from the slope edge) were not done because of
safety concerns_
Ground cracks and small holes were observed in a nearly continuous zone on the west edge of
Lot 3 (Bosch residence). In some areas, more than one sct of parallel cracks were visible. The ground
cracks lie at variable distance away from the edge of the slope, varying from about 3 ft to greater than 10
ft. The ground cracks were obscrved as close as approximately 10 to 15 ft from the northwest comer of
main structure and'deek foundations for the Lot 3 residence. The ground craclang adjacent to other parts
of the residential structure vary in distance from about 15 to 30 ft away. The ground cracks observed in
this area are estimated to lie above Lorian Woods Lot 5, a currently undeveloped lot.
09.2903 1MLojn Woods Sept 2003 Jidr. rcv 2'tloc 3 LANDAu AssociATEs
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Vegetation on the north part of Sequoia Ridge Lot 3 includes planted salal and other shrubs.
Closer to the house, vegetation includes a well -watered lawn and vegetable beds. The ground cracking
varied in distance from the existing struL,ture and frorn the top of the slope. Most of the cracks showed
vertical offset, with the ground surface lower to the west. The ground surface west of the cracks is
slightly hummocky and slopes downward to the west. In some areas, concrete landscape retaining blocks
had apparently been downset from their original placement, with vertical movement of these blocks
estimated to vary between about 3 and 12 inches.
The observed ground cracking indicates soil blocks that are no longer "connected" to the intact
and undisturbed glacial soil mass east of the cracks. These soil blocks have a relatively high likelihood of
movement outward and downslope. Based on the distance of observed cracking from the edge of slope,
soil blocks of 3 ft to greater than 10 ft thick may be prone to downslope movement. Movement of the soil
blocks can be slow or very rapid. Slow movement will be evidenced by increased cracking, opening and
offset on cracks that occurs over periods of days, months, and years. Slow ground movement may cause
cracks in patios, pavements, and structures that lie over the zone of movement. Rapid ground moveme-tit
occurs when the soil Strength bchwcen the soil block and the adjacent undisturbed ground is too low to
support the weight of the soil block. Rapid failure of soil blocks occurs over a very short period of time,
from a few seconds to a few minutes. There is typically no warning about when and where rapid soil
movement will occur. Movement of these soil blocks is most likely during and after periods of high
precipitation in the winter season, but should be anticipated at any time of the year. This type of soil
movement is likely to result in )andsliding and debris flows similar to what have been historically
observed in the Lorian Woods / Sequoia Ridge area. Homeowners and landowners near the observed
cracks in both Sequoia Ridge and Lorian Woods plats should anticipate a high likelihood of soil
movement and landsliding from this area over the upcoming winter.
RISK TO RESIDENTS AND GENERAL )PUBLIC FRo(✓1 OBSFRVT.D BLUFF CRACKS
At the time of our visit, no immediate risk from the observed ground cracks to public safety was
identified (because the downslope is undeveloped and the area is not readily accessible to, or used by, the
public). However, the presence of ground cracking indicates an unstable slope condition that has
increased risk of landsliding, particularly during wet wcathcr and the upcoming rainy season. This
situation creates a hazard to. any person present immediately below the potential landslide area. We
recommend that property owners in both Sequoia Ridge and Lorian Woods be informed of our
observations and the likelihood of landsliding during the upcoming winter and in future years.
Thu; Sequoia Ridgc Lot 3 homcownLr (Bosch) should be informed that their current setback from
the edge of slope (as defined by the recent cracking) to the structure and deck foundations at the
Q9251OJUEdrmaslv-podLnsl>>aucr4nWoods Sept 2003Ode rev2.dx 4 LANDAU ASSOCIATES
northwest corner of the residence is approximately 10 to 15 Lt. Because the house leas been built on deep
piles, the presence of these cracks probably does not pose an immediate risk to the structure. We
recommend that the homeowner inform their gcotechnical designer of the presence of active ground
cracking so that their designer can provide an assessment of the long-term risk to the structure. We also
suggest that the Sequoia Ridge Lot 3 homeowners conduct regular observations of ground conditions to
document rate of change of ground cracking. increased numbers of cracks, opening of cracks, and
downward movement of soil blocks are indications that the risk of active landsliding is becoming greater.
The Lorian Woods Lot 5 owner should be informed that they could be directly impacted by soil
movement and landsliding related to the observed ground cracks on Sequoia Ridge Lot 3. We suggest
that information about landslide potential also be conveyed to other residents in the Lorian Woods plat,
because large-scale landsliding originating from Sequoia Ridge Lot 3 could create safety concerns and
i could affect common areas and potentially other lots.
RISK TO CITY -OWNED PROPERTY FROM OwStERvtED BLUFF CRACKS
At die time of our visit, no immediate risk from the observed ground cracks to City -(awned
property was identified. However, the presence of ground cracking indicates an wistable slope condition
that has a relatively high risk of landsliding, particularly during wet weather and the upcoming rainy
season. The City's drainage interceptor system 1 A lies downslope of the observed cracks. Accordingly,
we recommend that the City discontinue regular observations of this system and use extreme caution
when making any other site visits or observations in the area.
This letter was prepared for the exclusive use of the City of Edmonds. Within the limitations of
scope, schedule, and budget, our services have been conducted in accordance with generally accepted
geotechnical engineering practice. No other warranty, express or implied, is made as to the professional
advice included in this report.
0925103 11EdrMaS11vPfCX 7411 tat criin Woods SE01 ZOO 9idr rev Z.doc 5 L4NDAu AS5ccIATES
770 6101 J 0 C ?ES INC us1Us 1:4:II r.UUI;UUI
We appreciate this opportunity to be of Scrvice to the City of Edmonds_ Please call if you have
any questions or if we may be of further service.
LANDAU ASSOCIATES, INC.
Deborah Ladd, P.E.
Senior Engineer
0�j "Pa" —
Dennis R. Stettler, P.E.
Principal
DL/DRS/ccy
No. 074114.011
09rLS03 1'l:ortn9slwpocW%4111ek063nwaoo5 Sept 2009 srdc rev 2 dx 6 LANDAU ASSOCIATES