20131025_Geotech.pdfI i i M. Bruce, P.E.
October 25, 2013
Mr. Jordan Schenk
jdschenk@gmail.com
Subject: Geotechnical Update Report
742 Daley Street, Edmonds
Proposed New Residence
Geotechnical / Civil Engineer
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DEVELOPMENT SERVICES
This engineering report presents the results of a re-evaluation of the site at 742
Daley Street, in conjunction with the proposed single family house development. This
engineer did an extensive geotechnical investigation and report dated July 28, 2006.
The City of Edmonds requires an updated geotechnical assessment, as well as
declarations consistent with Edmonds Development Code.
REFERENCES:
July 28, 2006 Geotechnical Report by D. Bruce, P.E.
Proposed project plans with topographic map
Site photographs by D. Bruce, P.E.
BACKGROUND:
As stated, this engineer performed a geotechnical investigation and prepared a
certified report dated July 28, 2006. The findings of the subgrade investigation verified
the presence of dense native sands.
The recommendations for foundation support included standard reinforced
concrete footings. See report.
This engineer understands that Mr. Jordan Schenk proposes to construct a home
in the southwest portion of the overall site. See site plan.
The overall site contains an existing creek, along with associated set back and
buffer dimensions. See plans.
SOILS FOUNDATIONS WrE DEVELOPAIFENT INSPECTION DRAINAGE DESIGN & F'Ef MIT LEGAL
P.,O, Box 55502 Shoro hne, VWashingt¢on gBI (206)646-9217 dbrueet)e@,gmaul.aorn
Attachment 29
Mr. Jordan Schenk
Re: 742 Daley Street, Edmonds
October 25, 2013
Page 2
The construction of the proposed house will entail excavation on the westerly
sloped portion of the lot.
OC OBER 2013 SITE EVALUATION:
This engineer performed a re-evaluation of the site (October, 2013). See
photographs.
No observable changes were evident with the slopes, topography, location of the
existing creek, and overall vegetation and slope stability. See October 2013 photo
sheet.
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The findings, conclusions and recommendations of the July 28, 2006
Geotechnical Report are valid, as of October 2013, sub ect to:
Geotechnical inspections during construction by this engineer.
Final plan review by this engineer to verify actual depth of soil cuts.
At the time of the this investigation and report, it is understood that maximum
excavation cuts will be no more than five feet (5.0'); hence, shoring will not be
required. However, if actual excavation exceeds 5.0', temporary shoring will be
required, subject to this engineer's evaluation, designs, and inspections during
construction.
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This engineer understands that the City of Edmonds requires a geotechnical
evaluation responding to Edmonds Community Development Code 23.80.050
23.80.060 and 23.80.070.
❖ 23.80.050: S ec`al Study and Report, a uire ents — Geologically Hazardous
Areas:
This engineer has investigated this site and submitted a thorough geotechnical
report dated July 28, 2006.
As stated in the report, the overall project is not geologically hazardous. The
subgrade soils consist of dense native sands.
Mr. Jordan Schenk
Re: 742 Daley Street, Edmonds
October 25, 2013
Page 3
The proposed new residence can be properly and safely constructed on the site,
subiect to geotechnical inspections.
This engineer understands that this site was designated as possibly geologically
hazardous due to the slopes in the western and southwestern portions of the site.
These slopes are not geotechnically adverse fpr the new proposed house, subject to
City of Edmonds review of plans and this engineer's on-site inspections.
The current Site Plan indicates a more than adequate set -back and buffer zone.
•3 23.80.060: D veto m nt anda:d:
Edmonds Development Code allows for alterations of the designated geologically
hazardous areas or associated buffers may occur for activities that:
1. Will not increase the threat of the geological hazard to adjacent properties
beyond pre -development conditlons. The proposed new residence at 742
Daley Street will not increase the threafof any geologic or geotechnical hazard to
the adjacent properties beyond a isting�conditiohs. In fact, the proper
construction of the new house using reinforced concrete foundations, improved
drainage mitigations, erosion control practices and final landscaping will
irn Lov+s overall slope stability.
2. The development will not adversely Impact other critical areas: This
engineer is not precisely sure what "other critical; areas" refers to. Obviously, the
near -by creek is located on the property. The required set -back and buffer zones
preclude any adverse impact to the creek, subject to geotechnical inspections by
this engineer and plan review and approval by City of Edmonds.
3. Alterations of the area are designed so that the hazard to the project Is
eliminated or mitigated to a level equlal to or less than pre -development
conditions. This engineer declares that the potential "hazard" is sufficiently
mitigated.
4. Are certified safe as designed and under anticipated conditions by a
qualified engineer or geologist licen ed�jn the State of Washington:
I, Dennis M. Bruce, P.E., declare that the site is not geotechnically hazardous for
the construction of the new residence (subject to inspections by this engineer,
nor is the project adversely impacting the adjacent properties or the adjacent
creek.
i
Mr. Jordan Schenk
Re: 742 Daley Street, Edmonds
October 25, 2013
Page 4
❖ 23.80.070: Develo meat tar dards S ecific Hazards:
Design Standards:
a. "Proposed r easesafety,
landslide occurrences below the limits of conditions, "and
1.2 r dynamicr «r proposed r r .nt
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sit,e i's below these limits, the proposed development shall provide
practicable ar w: to reducp to human safety and Improve
factorthe of o landsliding. In no case shall
a w factor
of be r r forproperty or r properties."'
I, D. Bruce, P.E., declare that the proposed development shall not decrease
the factor of safety for landslide occurrences below the limits of 1.5 for static
conditions, and 1.2 for dynamic conditions.
b. "Structures and improvements shall be clustered to avoid geologically
hazardous areas and other critical areas."
See plans. The proposed house is situated with a set -back and buffer from
the existing creek. Construction on the sloped portion of the site is not
geotechnically significant. Normal standard construction techniques,
subject to this engineer's inspections) are geotechnically approved.
c. "Structures and Improvements shall minimize alterations to the natural
contour of the slope and foundations shall be tiered where possible to
conform to existing topography."
Agreed. The proposed plans incorporate compliance with the natural
contour of the slope. This engineer` will provide on-site inspections to verify
controlled safe excavation and foundation construction.
d. "Structures and improvements shall be located to preserve the most
critical portions of the site and its;. ntural landforms and vegetation."
The project is set back from the exi s�tlng creek.
e. "The proposed development shall not result in greater risk or a need
for increased buffers on neighboring properties."
It does not.
Mr. Jordan Schenk
Re: 742 Daley Street, Edmonds
October 25, 2013
Page 5
f. "The use of retaining walls that allow the maintenance of existing
natural slope areas preferred over graded artificial slopes."
No artificially graded slopes are proposed. The proposed footing and
foundation stem walls will serve a$functional retaining walls for the existing
slope. The construction of this hot4se.will Improve stability► of the overall
slope.
g. "Development shall be designed to: minimize impervious lot
coverage."
See site plan for footprint layout of proposed house.
IV. Vegetation Retention:
This engineer observes that the majority of the lot area is not altered or
developed, and existing natural vegetation is maintained.
V. Seasonal Restriction:
There are no geotechnical conditions That preclude work occurring throughout
the year.
As stated, the subgrade soils are rela0vely clean sands, and as such are not
highly affected by excessive rains.
This engineer Eqquires that geotechnical inspections be performed (by this
engineer) throughout the project.
VI. Point Discharges:
i
The project plans for specific drainage controls.
Gutters, downspouts, and tightline discharge into the existing City of Edmonds
storm water system is proposed.
VII. Prohibited Development -Septic Systems, etc.:
No septic systems are proposed.
Mr. Jordan Schenk
Re: 742 Daley Street, Edmonds
October 25, 2013
Page 6
SUMMARY:
This engineer has reviewed the July 28, 2006 Geotechnical Report, as well as
re-evaluating the site (October 2013),
The findings and recommendations of the July 28, 2006 report are valid for the
proposed new residence at 742 Daley Street, as shown on the attached site
plan, subject to geotechnical inspections by this engineer.
Prior to permit issuance, this engineer requires a review of final plans to verify
actual excavation depths, excavation alignma-1.1t, and any potential need for
temporary shoring.
If there are any questions, do not hesitate to call.
DMB:vlb
Dennis M. Bruce, P.E.
Geotechnical / Civil Engineer