HomeMy WebLinkAbout938400545 Geotech AssessmentPLANNING CONBIDERATIONS
REPORT OF FtNDINQ$
I.~t~. 2~ and 4,8 of BloCk
: Cape George Colony, Division I11 JUN 1 4 2000
Outing June end July of 1995, ~lhwestum Territo~ie~0 InC, (N1
geotect~nlc~l recol~naissanca and pr~liminary pl~mnihg review of two p~'ceis w~in
George Colony, near Port Townsencl, W~hington, The lot.s, now noted as P~cei A and
Para:el B were the subject of a boundary line aclJustment c.,artled =ut by ADA Engineering
and Surveying. Parcel A Is ccx'np~sed of tile westerly portions of the fon'ner Lots 26
46 and Parcel B is compris~l of the easterly portion,s.
JEFFERSON COUNTY
DEPT. OF COMMUNITY DEVELOPMENT
The two parcels lr~cluda areas of st~ep slopo that would be c~fiec~ us a 'cdt~.at area~
under Jefferson County's lntedm Crlti~aJ ~e~ Ordlrla~ce. Devatopment of the lots is
further regul.'~ted by the Uniform Building Code es well as t~e-Jefferson County
Comprehensive Plan ordinance a~at cleais wl~ setbacks end height restrictions. The lots
are s~b]ec~ to covenants ~ncl restrictions regarding setbacl~ end Ileight lhet follow
properti0s within the subdivision,
BOth parcels offer s terM[oriel vi. aw to the south and some w-~:er view over Discovery Bay
on the west. A septic drainfleld suitable for single family residences on both lot~ he~ bean
designed and installed and the drainf'~I0 may have I::ean approved by Jefferson C~unty.
Site Layout and Development Cons~aints
The northerly boundary of the twO'parcels avarBges eb0ut 3S feet from t~e break In grade
at the top. of the .~outh-fac. Jng slope in the vicinity of ~e proposed house sites. The
Interim CritiCal Areas OrdinanCe rtotes ti'tat top Of slope I~uller mr~y ba reduced.for good
cause but the top or slope butler should n_ot._be~_e_~:: men 1.0 fa_aL.
Property line setbacks mus[ a~so be include0 in ~e narrow width :~vaileble for the.
constcuct,on of & house. The J~,fferson COunty Comprehensive P. lan governs setbacks.
The Plan indicates that'e rear yard se~a~ of 20 feet is required, willie a 5 foot setbacl~
'is required at ~he lot side. "I'Ve P[~ further requires that 20 feet of setbac~ be provic[ed
from ~ccess roads. ' '
Giean the irregu{er shape al~d odd position Of Pope, els A and B, i~ iS difficult to anticipate
how me Count~ authorities wi[I ~etermine wflat is ~e front, side and ro~r lot lines for
setback purposes.
2074427538
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Gaotechntcal Observetlona st Site
Opporturlitles f~' davelopment of the paresis is limited prin~ ~ ~ steep slope
t~e south ~at is d~pi~ed in ~e profile i~uded In Fig,s 1. Ma~ame~ token at
site indi~te ~h~t the grOSS ~eep~c~ of the s~pe ~ ~ ~a pm~S0d bu~ng
vBfleS trO~ ~ut ~, to ~, ff~ ~e hori~l. ~e toe et the slaps h~
excavated' to~ the ins~il~on ~ ~e septic drainflald, leavin0 ~ ~emtee~nea posen
'the lower pe~on ~ ~e elope.
Sells at th~ prestONe b~idtng s~s sP~r to be p~ of the ~ag'~ Series ~ Ideated
gr~elly s~dy loams. ~a ~in s~ls of ~ group ~e ~pi~l~ undert~n by
~amlnafion of ~e slo~s, ~e s~n ~d seve~ ~sures in ~e ~lnW M ~e p~ls
unconsOhda~ ti~ lor~oons ~ ~,,'
leaving un~oA~ rocA, s~ ~ si~ debris. Su~s~ue~ ~e~dl~ ~
lodgement tiff.
Visual i~pe~ons of ~he s~ a~ ~ ~wer areas indl~ ~t ~e ~l Is wld~pr~ad.
appears that tills m~y g~e w~y to s~ g~vels ~at ~N~ ~ ~= sas as
and s~ ~ w~ s~pend~ In gl~al me~ater.
Glaclai fill Is am~g ~e ~gest ~ ~st enduri~ ~ ms~ls ~ ~e region.
tough t~! that ~s print ~aS A ~lg~ ~le of in~rnal fr~ ~d la untikeN to
subjoin'of ra~d sll~g la, utes. ".
. Fou~aflon ~P~ "
Co~on~ al ~e s~e suggest ~t ~ is ~ssl~e to ~na~u~ a m~fde~ to ~c ~nlmum
top ~f s~Ope b~e~ ~ is,' ~ln 10 feet of ~e ~ ~ slope, tn spite of the relative
mabl~ of ~e ~11 underNing ~ s~e~ su~cial slumping ~ seismic a~Ni~ ~uld
~'a ~oils in ~eas thst ~se to ~ das~n~lng slope. 'To achl~e the
lounflaflon stabili~ ~d aa~ r~uired by Semen ~ 0t ~e. Uniform ~uildi~
~undaflon is m~mmended. ~er ~at ~n~ piles era wal~ suited
approximately 20 tee~ ~ de~ a~ong ~ ~,UlHe ,,,,- ,~ -
slope.
' ' sro feet ~ ~e ~p ~ ~e slope would
~nstm~i~ 01 a ~ed ~n~ma t~l~ to~0ati~st is
to require ~nst~on. Pole ~pa ~ns~u~o~ coul~ N~ ~ employed at the
to,loWed ~ the ~ - · ..... - -
to ~nventlonal
Preliminary study of' the Sites Indicates met the slopes at tl~e site ate stat:de enough to
accommodate light~eight tes]c~entlai ssructu~'es to the' minimum top of alol::~ aettback
under current ordinanCee. ~tlope creel( and minor alurAping may be ob:served In a zone
that ts close to the top ot bluff. As a result, the use of auger ca~t piles is recommended.
Oetalls of the foundation and piling .system shoulc~ be developed and approval by NTI or
equal professional engineer prl~ to issuance ot · 13Ullding. permit after We footprint anti
dlmenstona of the proposed reside, r~e are known,
81te Planning Co~eraUona
'rrm dual requirement for a m~nimum ~0-~ top ot ~ ~ ~ a ~ ll~e
~n~r~n wh~t Is ~i~te on ~e ~0 I~. If deffe~on ~u~ de~lnes
~a~ Im line is ~ 'rear" I~e, ~ onN a f~ fern wouU be ~l~le for ~n~u~n.
Ntern~ely, ff the m~e like~ d~ermln~ ot 'side' pro~ lino is ma~e~ on~
of set~k ~m ~ n~ line would be required. In ~ dr~n~, a
building e~lope of abo~ ~ fe~ ~p~, on first ~sls, ~ be ~a~le. '
S~backs from ~e a~ees ~a may or ~ nm appN ~ ~e h~me~ead d~eway
~n~ara~on ~8t e~ ~ ~e site. ]n ~y ~ae, ~e o~l~s for po~oning a ~uee may
~e furor tlm~ed by ~e r~uir~e~ tO p~de pa~lng on ~,e s~o, D~ to ~e ~ffent
~nfiguration of ~e ddva~, R app9~ that a ma~ ~ ~e ~de~ ~on of
building 'site may have ~ be ~e~t~ to ~rking or to d~ay.
Fe~O~i~ of ~n~on 8h~ ~ te~ed by devel~ment of a pre~min~
~n~ ~ ~mlimi~ ~e plan, fol~wed by a m~ew ~d 1~ line s~
by Jaffeman Coun~ ~o~es. ~e exi~ence.ol ~ a~pr~ se~: ~(m~ s~uld
verified ~ w~. '
Consu~ ~ a p~ ~ ~ans~ s~age d~ ~ ~o~ ~ ~e ina~iled
~ank/dmi~eld ~11 ~ ~len~ng. tt s~ 'like~ ~ ~ch ~on ~ll ne~ to
done by h~ in ~e ~ugh soils as mo= kinds of equip~ ~nnot be =afe~
on the ~o~. ~uo~ ~ welded po[ye~ytena ai~ that ~ resist
tension' ~y be the ~ pr~u~ ~r ~e pl~ll~. .
Sumrriary
Rec:onnalssence investlgat~on of the subject property indicates ti'tat ttlem a'e generally
favorable geologic anct geota~3hnical conditions at stta.. Nevertheless, ourtent 13uffer end
setback ordinances may res~ict the buildable zone to e eize that Is Ine43proprlately small.
Oeterminations of beunclery and road aetbaok to be made by Jeffer~3n county upon
~O'd TS~ ~2,£ 09£ ~1~3 IIW~Bd 03 -I-~£ 8~':~T
c;O'd -IU.LOJ.
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d~,~' .
submission of a prelimlnan/site plan appear to control ~he fessiblltty of c~nstruction On
the parcels,
Auger casl:13iJes are' '
of the sough.facing recommencle¢l for ~r~em msi~tlal ~Vu~n ~a ta ~e top
es~pment on ~o ~~. FounOaflOn de~, tayo~ and ~ling
~nflguratlon ShOul~ be r~l~ed by ~ia '~ p~r m ~nst~a~on.
Llmltations
This repo~t is preliminary in natural;nd is based on an inspection of me extstltlg site
conclitions. The site investlgatiort wa,~ made without We benefit of detallea measurements,
geotechnlca; materials teat~, borings ~ data'led investigation of the aubsur~ce com:titior~.
The work was clone ~3 the Standard Of care ~ in acc, orda~ee w~. the prac~e of the
engineering profeaBio~, but unforeseen and unknown subsurface conditlona Cermet be
completely understood by rapid sUrveys end e~amin~on of surface conditions. Raclu~-
tion In risk and batter reilal3ili{y ef ~nc. Ju~iona and reCornmend~ona can be obtained by
rrmre d~,eiled Investigations Of tho ~ that Include borings, accurate measuremen~ and
laboratory tes~ing of materials. The Engineer encourages No user who wishes a higher
0agree of reliability of Investigation results to obtain such services.
Unless oz3nstructlon plans are reviewed and oonstruction I~lspeoted by the Engineer, no
wsrtanty is made COncerning th~ confom~ity of the finished ~r',stm~{3n to the conolu.
sions and recommendations of this repot[
T~e Observations, inte~mtations and cOnclusions herein ar~ 13seed on the' oeherelly
accepted principles of engineering and geO~3gy. This wan'anty is in lieu of all others,
elther express or implied.
This report is Intended ~r the s~le use Of Mr. Chiles Phillips and may be used by 0them
only with his express permisston. ~ ·
Sincerely yourS,
Steve S. Luxton MS~ J:'.F_
Professional Engineer