Field Report from Landau.pdfLAN
a .14,
Project No.:
Client/Owner.
Project Name:
0074189.010
City of Edmonds
Landslide at Pak Residence
Location: 16109 731 Place, Edmonds, Washington
Weather Conditions: Sunny 1-45-50 degrees
Prepared By: Carlo Evangelisti, P.E.
SITE OBSERVATIONS
General
Field Report
Report No,; 1
Date: 01/22/16
Permit No.: NIA
Reviewed By: SZW
Landau Associates (LAI) arrived on site at approximately 3:45 pm and met with Leif Bjorback,, Building
Official, with the City of Edmonds. The purpose of our site visit was to visually evaluate the stability of
recent landslide that occurred on January 22, 2016 behind the residence located at 16109 731d Place in
Edmonds, Washington.
Upon arriving, we observed the landslide directly to the east of the residence. The landslide debris
mass was approximately 35 feet long (parallel to the house) and about 30 feet wide (perpendicular to
the house to the east). The edge of the debris mass was located about 25 feet east of the house at the
approximate edge of the landscaped backyard. Up slope to the east we observed the landslide head
scarp estimated to be about 150 feet upslope from the house. The landslide debris mass consisted of
saturated, brown, gravelly sandy silt/silty sand. Water was visible draining from the landslide debris
mass, in addition to water draining from 4 -inch diameter perforated pipes previously installed by the
City on the slope. From below, we observed the headscarp to be void of vegetation but were unable to
access the scarp to determine soil type comprising the scarp.
After visually evaluating the slope, it is our opinion that the recent landslide has come to equilibrium
and currently does not pose a significant risk to the residences below the slope under static conditions
(i.e., no seismic loading). In the event that additional slumps within the failed debris mass or further
upslope were to occur, there is a catchment area that will help minimize damage to the house. We
advised the homeowner on behalf of the City, to monitor the slope for additional movement, particularly
in the event of heavy rains, for any observable movement, and to call the City if movement occurs.
In addition, The City informed us that the landslide debris mass had covered up a stormdrain catch
basin near the toe of the slope. We advised the City to uncover the catch basin pipe for blockage that
may have occurred with soils moving through the grates of the stormdrain. We also advised the City
that the 4 -inch perforated drainage pipes should also be inspected and repaired if needed.
Prior to leaving the site, we accompanied the City, while they notified residents located at the top of the
slope of the recent slope failure. In addition, we were able to access the top of the slope through the
residences and observe the slope failure from above. Visually evaluating the the top of the slope, we
did not observe any evidence (i.e., tension cracks, soil movement, etc.) indicating the potential for
future, immediate landslides that could undermine or impact the residents at the top of the slope.
LAI left the site at approximately 6:00 pm and will return at the City's request as needed.
130 2nd Avenue South . Edmonds, WA 98020 . (425) 778-0907 ® fax (425) 778-6409 . www.landauinc.com
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LANDAU
!AASSOCIATES
IMBIN =0
Visitors: Carlo Evangelisti.- P.E. (LAI). Leif Biorback (City of Edmonds) City of Edmonds utility
w/.- .r
Unsatisfactory Conditions & Recommended Correction: As noted above
Attachments: None
Distribution: Mr. Leif Biorback. Citv of Edmonds
Landau Assodates'reprosonlatives are onsile solely to observe operations of the contractor donVied, to form opinions about the adequacy of those operations," report
those opinions to our client. The presence and activities of our field representative do not relieve the contractor from its obligation to meet contractual requVements The
contractor retains We responsibility for silo safely and the methods, operations, and sequences of construction
A preliminary copy of the Field Report may be ny" solely as evidence that fmld observation was Womned. Observations and/or concJusions andlor rocornmendations
conveyed in Me Field Report are by Landau AssGclates'project manager or designee. A reviewed Field Report shall take precedence over a
211116 PW74%sBM..dmwwsSWPOIaip,ffeFeed Repart,,d= LANDAU ASSOCIATES
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