CRA19940164.PDFIIIIaII�I I CA FILE NO. �
Critical Areas Checklist M (Cic4DI
• Site Information (soils/topography/hydrology/vegetation) 6,
1. Site Address/Location:
2. Property Tax Account Number:
3. Approximate Site Size (acres or square feet): I i7O®
4. Is this site currently developed? i< yes; no.
If yes;. how is site developed? 1.E \F- :V-Al!7jer'vO'c—,
5. Describe the general site topography. Check all that apply.
L
Flat: less than 5-feet elevation change over entire site.
Rolling: slopes on site generally less than 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: 0 ; Approx. Depth:
7. Site contains areas of seasonal standing water: ; Approx. Depth:
What season(s) of the year? I
8. Site is in the floodway �fl floodplain {J (7 of a water course.
9. Site contains creek or an area where water flows across the grounds surface? Flows are year-
round? V () Flows are seasonal? (What time of year? ).
10. Site is primarily: forested
urban landscaped (lawn,shrubs etc)
meadow ; shrubs
11. Obvious wetland is present on site: iJ U
;mixed V ;
U
For City Staff Use Only-
. Site is'Zoned? KD '2D
2 SCS maplied soil
3. Wetland inventory or C.A. map indicates wetland present on site? A)a
4, Critical Areas inventory or C.A..map.indicates Critical Area on site?..
5 Site within designated earth subsidence landslide hazard area? Y�
'6. Site designated on the Environmentally Sensitive Areas Map? ih
DETERMINATION
STUDY REQUIRED
WAIVER
Reviewed by—�!i/Ll4&2�
Planner
CONDITIONAL WAIVER
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RECEIVED
J U L 2 9 19944
PERMIT COUNTER
690.199'
City of Edmonds
Critical Areas Checklist
The Critical Areas Checklist contained on and submit it to the City. The City will
this form is to be filled out by any person review the checklist, make a precursory site
preparing a Development Permit visit, and make a determination of the
Application for the City of Edmonds prior subsequent steps necessary to complete a
to his/her submittal of a development development permit application.
permit 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
Checklist should be easily available from
observations of the site or data available at
City Hall (Critical Areas inventories, maps,
or soil surveys).
An applicant, or his/her representative,
must fill out the checklist, sign and date it,
With a signed copy of this form, the
applicant should also submit a vicinity map
or plot plan for individual lots of the parcel
with enough detail that City staff can find
and identify the subject parcel(s). In
addition, the applicant shall include
other pertinent information (e.g. site
plan, topography map,. etc.) or studies in
conjunction with this Checklist to assist
staff in completing their preliminary
assessment of the site.
I have completed the attached Critical Area Checklist and attest that the answers provided are
factual, to the best of my knowledge (fill out the appropriate column below).
Owner,/ Applicant:
Name
1�6-Ast
Street Address
qAw���,6yte,* �--60 7
City, State, ZIP 0� 1� 0 Z ('0 Phone
Signature Date
Applicant Representative:
u
•
Wko"D to :)S — l�q� 1 �� OdL
Name
a (no
Street Address
3�
City, State, ZIP Phone
29 �.
Signature Date
Ull
June 1, 1995
HWA Project No. 95084-200
City of Edmonds
250 5th Avenue North
Edmonds, Washington 98020
RECEIVED
JUH 0 2 1995
PERMIT COUNTER
SONG WEST
&AS SOCIATE S,INC.
Geotechnical Engineering
Hydrogeology
Geoenvironmental Services
Testing & Inspection
Attention: Mr. Kirk finish
Subject: CRrrICAL AREA STUDY - PEER REviEw
Spiro Residence Pool Addition
15631 75th Place West
Edmonds, Washington
Reference: Proposed Lap Pool, Geotechnical Engineering, by Hemphill Consulting
Engineers, dated March 20, 1995.
Dear Mr. Vinish:
In accordance with your request, Hong West & Associates, Inc. (HWA) has completed a
geotechnical peer review associated with the proposed new swimming pool construction
at 15631 75th Place West in Edmonds, Washington. As part of this study, we visited the
site and reviewed the consultant's methodology, conclusions, and recommendations as
summarized in the report referenced above. Particular emphasis was placed on
recommendations relating to the City of Edmonds Critical Areas Ordinance (Ord. No.
2874, rev. No. 3014).
In addition to the referenced report, we reviewed the following documents:
1) Geotechnical Engineering for the Proposed Spiro Residence, to be Located at
15631 75th Place West, by Hemphill Consulting Engineers, dated December
10, 1990.
2) Addendum to Geotechnical Report, Proposed House, Located at 15631 75th
Place West, Meadowdale, by Hemphill Consulting Engineers, dated December
24, 1990.
3) Preliminary Surficial Geologic Map of the Edmonds East and Edmonds West
Quadrangles, Snohomish and King Counties, Washington, by M. Smith, dated
1975.
4) Edmonds Landslide Hazard Map, by GeoEngineers, Inc., 1984.
19730-64th Avenue West
Lynnwood, WA 98036-5904
Tel. 206-774-0106
Fax. 206-775-7506
June 1, 1995
HWA Project No. 95084-200
The consultant's report (March 20, 1995) references document No. 1 above and relies on
the subsurface investigation therein to formulate recommendations for the proposed lap
pool. Documents No. 3 and 4 indicate that the subject site is within the mapped
boundaries of the Meadowdale Landslide, which occurred as a result of an earthquake in
1947.
Methodology
The City has requested we review the consultant's methodology and evaluate whether the
subsurface exploration, laboratory testing, and analysis was sufficient to adequately
address slope stability concerns, drainage characteristics, erosion potential, and to provide
recommendations for site development.
Based on our review, it is our opinion that the subsurface investigation performed in 1990
was adequate to characterize the soil and groundwater conditions in the area of the
proposed pool addition. It is our further opinion that the consultant's 1990 and 1995
investigations provided sufficient data to support appropriate analyses and prepare
recommendations for site drainage, erosion control, slope stability, and general site
development.
Critical Areas Ordinance
Steep Slope Hazard
According to the City of Edmonds Critical Areas Ordinance, a Steep Slope Hazard is any
slope with an inclination of 40 percent (2.5H:1 V) or greater, measured over at least 10
feet of elevation change. For such slopes, a buffer of 50 feet is required. Building
setbacks from the edge of the buffer must be a minimum of 15 feet. A slope exists
immediately west of 75th Place West which may meet the requirements for a steep slope
hazard. The proposed swimming pool setback is 35 feet from the front property line,
which is approximately 70 feet from the top of this slope. The setback is therefore within
the requirements of the ordinance. It is our opinion that the recommended setback is
reasonable.
Landslide Hazard
The Critical Areas Ordinance defines a Landslide Hazard Area by several criteria, one of
which is "any area which has shown movement during the last 10,000 years." The
ordinance also refers to the Edmonds Landslide Hazard Map (document No. 4, above) for
classification of Landslide Hazard Areas. For a site classified as a Landslide Hazard, a
Critical Area Study must be prepared which shows compliance with the following two
conditions:
95084-2.DOC 2 HGNG WEST & ASSOCIATES, Ixc.
June 1, 1995
HWA Project No. 95084-200
1) The proposed development will not decrease the slope stability on adjacent
properties; and
2) The landslide hazard is eliminated or mitigated such that the site is "stable," as
defined in City of Edmonds Ordinance 2661. For landslide hazards from deep-
seated failures, which cannot be realistically eliminated or mitigated, the
definition of stable is "areas classified as having a probability of earth
movement of 30 percent or less within a 25-year period.
The City of Edmonds has requested HWA to determine whether the referenced report
meets the requirements of a Critical Area Study. As previously mentioned, the site lies
within the boundaries of a relatively recent landslide and therefore is classified as a
Landslide Hazard Area.
In our opinion, the consultant has adequately addressed items No. 1 and 2 above.
Regarding item No. 1; the consultant has clearly stated that the proposed improvements
will improve slope stability by reducing loading and improving subsurface drainage. In
our opinion, the consultant's recommendations for subsurface drainage are appropriate.
In addition to groundwater drainage, the drain system should serve as an interceptor for
possible pool leakage or overflow. We agree with the recommendation for a filter fabric
encasing the drainage aggregate. We also agree that a geotechnical consultant should
observe the pool excavation, which will allow for field changes to the drainage system, as
conditions warrant (e.g. higher capacity drains if substantial groundwater is encountered).
We agree with the need to control erosion at the outlet of the tightline drain.
Regarding item No. 2; the Edmonds Landslide Hazard Map shows a probability of 30
percent for earth movement in the next 25 years for the subject site. The consultant's
report predicts improved site stability from the proposed pool addition. Therefore,
requirement No. 2 appears satisfied by the combination of the consultant's report and the
Edmonds Landslide Hazard Map.
Summary
It is our opinion that the referenced report meets the requirements for a Critical Area
Study as specified in the City of Edmonds Critical Areas Ordinance.
It should be noted that the scope of services performed by HWA was limited to a site
reconnaissance and review of the referenced documents. Field studies and/or verification
of calculations were not performed; accordingly, we can offer no assurances regarding the
performance of the site. In addition, the services performed consist of professional
opinions made in accordance with generally accepted geotechnical engineering principles
and practices.
950842.DOC 3 HGNG WEST $ AssociATEs, INc.
June 1, 1995
HWA Project No. 95084-200
O.O
We appreciate this opportunity to be of service. If you have any questions, or if we can be
of further service, please do not hesitate to call.
Sincerely,
HONG WEST & ASSOCIATES, INc.
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EXPIRES
Andre b. Nfar6. P.E.
Geotechnical Engineer
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95084-2.DOC 4 HONG WEST $ ASSOCIATES, INc.