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Home My WebLink About821262012 Geotech Assessment# i - 1 's (J/`~ 7 /~ GEOTECHNICAL REPORT Pr®pared For Barbara Bodker - ~--~~ ~--~ ~ November 3, 2006 _ For the Pro a Described as p rtY . Tax # 821262012 ,~, oc~ Section 26, Township 28 North, Range 1 East, W.M. .... Jefferson County, Washington Q d _ _ { Prepared by ~ ~ t ,,..--~~~ '~ ~ ` NTI Engineering and Surveying - ~ ~- ~- ~ _..~_ ~ 717 S. Peabody. Street Port Angeles, Washington 98362 Phone 360-4528491 .Fax 360-452-8498 Web Site www_nti4u_com E-mail in#o@nti4u.com ;2067662170 -~4aM; QOEING intl sa les ;2067662~7Q ~ 4," ~_ y ~ - a '~:~ .. Geotechnical Report Tax # 821262012 ~" ~, W ~~~~mber" 3; 2006 Mhara 13odker ~':'ti 49'" Ave SW N;atli~, WA 98136 ': Sf~;hject: Geotechnical .Report for Tax # 821262012 located in Section 26, Township 28 North, Range 1 East, W.M., Jefferson County, WA ~rar Mrs. Bodker: .:,~;~~~grour~d ,"-~t ,your request, NTI Engineering and Surveying {NTI) conducted a bluff stability inspection. at ,:; ~'~ove referenced location on October 25, 2006. The purpose of this inspection was to - ~.~:~ef-ve the'marine bluff at the subject site byvisual means and report our findings and opinions ,~s~ards to the relative stability of the bluff, in general accordance with the Jefferson County ~,1-~ified Development Code (UDC}. It is our understanding That you desire to construct a ingleR i ,,residence ort the property. ~~ :~la~ject waterfront property is located just south of 112 Fir Street in Paradise Bay, south of =::~ t ~ udlaw. The property overlooks Puget Sound to the east and is bounded en the north, so-.~th, and west by residential property (Figures 1 & 2). The upland portion of the property is .-~~d~minantly wooded with mature trees, except for a cleared house site, which is vegetated in ~i.tsi ~ and grass. The proposed house site is in line with the house to the north and was marked ;'~e fieldwith wooden stakes (Photo 1) and was approximately 35'x 33' in size. ?"he approximate location of the proposed house is shown on Figure 3 and is about 175' from ~~ t~~a Adge of the marine bluff, and about 75' from the top of the gully to the south. Septic ~c- :est pits were excavated west of the house site revealing sandy soil (Photo: 2). ~~ "~ a^pography of the upland slopes gently eastward toward the bluff, with a gully along the . _,n side of the property and a beach access trail on the north side of the property. ;;::proximately 12' east of the house site, the land drops down ashort --22° slope for about 17' n-~; tnen the slope changes to -12° the rest of the way to the beach following the trail. ~:lu~f in the vicinity of the property is about 40' high with an average slope angle that varies ~~~~ about 35 degrees in some areas to near vertical in other areas (Photo 3}. However, the ~:~ i ~~ ~ CC k' ~ ~ ~GC ~ ~ ~ ~ a I ~--.---v.~ n i , •i ra~``' ~~~>>=24AM; BOEING intl sales .;2067662170 #3% i~. ~~ - ~'' 3 1'~i 4 ~ e ~.. `' ' ~ ~~~~h.lower at the subject property due to its location at the mouth of the gully (Figure 3). :~~ AF the bluff is being undercut from wave action at high tides and during storms, which c:;ntributes to periodic slides on the bluff face. The gully to the south was'vvel! vegetated with no - ~,j Bible evidence of recent sliding. There was water flowing in the gully at the time of the site ;~t, reportedly from a spring that surfaces west of Paradise Bay Road. Site Geology '~~ ? ~y~/eshfhgton State Department of Ecology's Coastal Zone Atlas maps the soils on the ,. ~ ~.-~; ty a~ Vashon lodgment till {Qvt1 }and Undifferentiated stratified sediments older than `, '_,J~shon lodgement till (Qpf}, The till soil is described as consisting mostly a compact mixture of .~~~~~I e'er to sand size particles with some silt and clay. The Atlas lists this soil as excellent for .. ~:~atiorr stability, goad for seismic stability, and says that that it stands in steep`natural and/or slopes for long periods. The undifferentiated soil is described as consisting mainly of sand and gravel, but in some areas contains silt, clay, peat, and possibly till. Environments of a~posif~on of this unit include glacial outwash, glacial lake deposits, and interglacial alluvium i~d lake deposits. The Atlas maps the stability of the bluff at the mouth of the gully as Stable, a~ ~ re bluff orr either side of the gully as Unstable recent slide. The upland is mapped as 4'° ~~~oart~ent of Ecology's "Geology and Ground-Water Resources of Eastern Jefferson a~,y, Washington":maps the soils in the area of the subject property essentially the same as '~ ^ C~ ~~stal Zone Atlas. :: ~dfng to the Soil Survey of Jefferson County Area, Washington (United States Department ~~ Agriculture, 1975), he subject property is in an area mapped as predominantly Belfast silty ~?^y loam (Bm} and Kitsap gravelly loam (KsC), with Alderwood gravelly sandy loam (AIC) to the „c..th (See Appendix). The Belfast silty clay loam formed in alluvium and is described as being ^ryr~y drained. with moderately slow permeability and a seasonal water table at a depth of/Z to 3 foot. The Kitsap gravelly loam formed in glacial (acustrine or marine sediments on upland 'perches, terraces, canyon slopes, and ocean bluffs. The Alderwood soil formed in glacial fill an :ial terraces and is sandier than the soils mentioned above, which more closely. resembles ,m sandy soli observed in the drain field test pits. su,=:l observations made in the drain field test pits at the site, and from surface soils on the :~r:e resealed sandy, gravelly deposits with a dense layer of silt at the toe of the bluff, ~.csnclusions and Recammendattons "~'~~~re have been periodic slides on the marine bluff in the past and future sliding is possible. ~;-cposed house will be located approximately 12' from the short slope, 175' from the top ,' _~ or the marine bluff, and about 75' from the top of the gully to the sauth. These setback .':~ ices a~e consistent with Section 1845 of the International Building Cade (IBC}. Section ~ecor~mends: buildings be a distance of at least H/3 away from the top of the slope where 'eight of slope`(Figure 4). The septic drainfield will be located west of the house, not `~a_rveen the house and the bluff. >~ ~ ~ipara our investigation and our understanding of the project, it is our opinion that the ~r~.;~osal will not contribute to slope destabilization and we recommend approval of the project, room a geotechnical perspective. £ ~ Jf t4: DEC 1 8 2006 __.~i r~` - 24AM; BOEING Intl sales ;2067662170.. T S. S~ ~ .~ l Z., ". - 2' . ~ ~ ~ - Y~ `~Ilowing recommendations should also be considered with ~egards to the proposal: 1. It will be necessary to maintain ground cover in order t reduce erosion from surface runoff. Any bare areas that develop should be reveget~ted where feasible. Native deep-rooted vegetation that requires little or no irrigation would be the most beneficial. Please consult the enclosed publications for further information. 2. Vegetation on the marine bluff and the other slopes pr (vide stabilization to the soil and helps remove water from the sail. Existing established egetation should be left in as natural state as possible. As far as pruning for a better iew, minor thinning and - pruning should be done in such a way that minimizes disturbance to the soil and root zc~rte and that insures the continued health of the vegetation. Large trees on the bluff or other slopes #hat are damaged or are in danger of being blown over due to ~~s~dermining of the trunk should be evaluated for possible removal due to the cetrimental effects of having large root systems being wrenched out of the bluff soils. If trees are removed, it would be beneficial to leave the trunk in place so that the roots. can continue to provide soil stabilization until they deteriorate. 3. :Tree limbs, lawn clippings, etc.. should not be thrown over the bluff or gully slope '.:because these piles have a tendency to damage/kill the underlying vegetation which in turn increases the erosion potential of the soil 4. !-leavy irrigation or other activities that would contribute large quantities of water to the .soil should be avoided. 5. Surface runoff from hard surfaces such as roofs, driveways, walkways and patios s'Clauld be controlled and routed to a drainage control device such that surface,water discharge to adjacent properties does not significantly exceed predevelopment ' .conditions, and additional erosion is prevented. The Department of Ecology guidelines;.. as well as any other local codes should be followed. NTI .can complete an engineered drainage, sediment and erosion control plan for this property if requested. 3. Silt fences or other sediment control devices may be needed during. construction.. such that offsite sedimentation does not,significantly exceed predevelopment conditions. ,. Drainage control devices should be maintained in good working order and. inspected at least once a year. =~;~r fi.~-tner information please review the three publications {included with the original of this report) published by the Washington State Department of Ecology {DOE) entitled: "Slope `:~b`Iization and Erosion Control Using Vegetation", "Vegetation Management: A Guide fore Vie: Sound Bluff Property Owners" and "Surface Water and Groundwater on Coastal Bluffs". ~~se publications can also be viewed on the DOE website at: ~ttp://www;ecy.wa.gov/biblialsea.html under the 1993 and 1994 year heading. The DOE website ~'so contains additional useful information regarding slope stability and site development; this f~rence is .highly recommended. ~~ ~~: I,~~~~rg--- ~ ~ ~ 1 ~"~~~ t E ~ s " ~ oEC ~ 8 2aos .v _f., __ d~~=-. ~-- _;~~':24AM;130EING intl sales ;2067662170 #~ 5/ i i ,-f„.~ +t ' ai - - ~->~ i s ~ ~~ s report has. been prepared for your exclusive use in conjunction with the above referenced ~• ~ ct. The report has not been prepared for use by others or for other locations It may be . =cr'Qfher purposes only with the expressed written permission of the Engineer. 'J~~ i:h n the limits of scope, schedule and budget, this report was prepared in general accordance ~fi~~ accepted professional engineering and geological principles and practices in` his or similar I~ a~ities at the time. the report was prepared. No other warranty, expressed or implied,: is made.. ~; to the conclusions and professional advice included in this report. The observafions, conclusions and recommendations presented in this report were based on visual observations of the subject property at the time of our site visit; no laboratory. tests ~~>-e ~::rfcrmed. Soil and geologic conditions can vary significantly between test holes ar~d/or ~wfiGce outcrops. If there is a substantial lapse of time, conditions at the site have changed or a v~pear different than those described in this report, we should be contacted. and retained to :•~~l::ate the changed conditions and make modifications to our report if necessary. -icy, Ely, 0~R't A. ~Fq ji~`+~~RTHWESTERN TERRITORIES, INC.. ~0~~ oF~wasy~yco[y h z -t A._ i_each, P.E., MBA '° ~~ i;~ai Engineer ~'ayton, L.E.G. ngiveering Geologist 3 i'llReportslBODB0601.b1uff stabiiity.26{28-1 E).Paradise Bay.doc f ~ r s g+ 1 r~~, i ~~~ ~~ DEC 1 8 20Q6 I.e.F. ~~ I ..~. _. ~°~, ~F lanz ~o ~'~ oc ~~s~s~~ ~`~ Fss~on-At ~°~ EXPIRES 12!30/2006 ~~~ ~~~ ~ ~~~~ ~~~ ~ EA01rc~~gQ ~" ~~P :191 ~,~ ~ag~ ~o~ William C, Payton Jr. -'.8-0E; 1.1:24AM; BOEING intl sales Appendix ~' r k }f ~ tea Y`ep' 4.,,,'a ` R ~ D ~ ~ ~ 1 ~~~ _ f1` 8-06; 11 :24AM ;.BOEING Intl sales 20676621 7.0 # -7~ + 5 ~,I~ . ^t ~ ~ ~ l 6~ver j ~ ~ ~ I f ~ e alley l~! Pork L - 1 ~_ ~ rr ~~ T I ~ ~ ~/~Y ~~,, I ~P Ludlou~ '~ ~~~,~ ~ Golf Caursg ~ ~I ~ l \ Yrm ~ \ _-_3E~_ ~,~ `, '~ .~~ >~ _ F ~ dom......-,~.......~.. ...., j ~ , ~1 I a~ y~ ~ ~4 ~f~ ~° o~c ~ $ coos ~ ~. ~~ v~ . _ ~ ~. Auget5~wnd `~ *~$~ ~ ---~` l ~ ~~ ~_~ .. , ~~'•. -~ ~~t,` 1`4~~ ~ti:: '~a. ~,:t I~ 1 ~~i : ~~ ~~ ~, !e ; -': ~- Figure' 1 ~1 ,~i '.=24AM; BOEING intl sales 5 ._ `~ - ;.J ca ~FfR S~T ei ~ ~4 ~w.,:~. ~„ ~. cr°~ , ~' .~ # ~ ; r ~~ „_. ~ ~.Y -: , 20676621 70 #.. 8. 15 ~, ~ ~ , ~(a ~ `~~ '~~ {~ DEC 1 8 2006 - i 1~...-~ ~--~----~-~. ~ 19~ ' ~(, L [ n u 4 i 3 7~ ~ ~. p.'{~, ~ _~ ~ qtr ~ ~ ~~ ~~~a~~ ~ ~~5 rx ~J i ~' ~ ~;~~ ° ~~ ~'~ Si.~u y S ~, 5 ~_ ` ` ~' ~ i Approximate ~ ~° ~,~ E"~ House Site ~4 ~ ~, ~~ ~.~ ~~~~ %~ ~ ~ ~ ~ t ~ j` 11 ~ f ..a'4'~ ~~ ~ ~ s~. i _ s~'- ~ ~+-"' ~ Y y~ , 2 ~' ~: ~~: ~- y ~~g ~~~ ~-'S` ti +~ ~ ~ ~ ~ -~-. ~, Y. S ~s:r, ~: 1 ~: ~ +.. r ti is `_ r ; ~ ; '.~ w: `~ ~ ~~~' ~~~- ° -~.-...~~: Figure 3 ''`; .._ratitf~! ~ .c~xe, co~C,:,r .~ ~na~. G!S 'l~ ~~'~...... ' ~ , • i ~/ ~-' :.,.. _ .. ~° ~ ~`~~ c~~ ` 89 ~~ k } DEC 1 8 2046 ;20.67662170' # 10 ~" 18 --~=--- ,~ }~~F ~~~~ ,s~~x~ DEC 1 8 2006 - , ~ ~ ~ ~i:24AM; BOEING intl sales ~ .. ' ~ '~' 2 r. -.iii y ~ ~~ ~ ~+A.~~ f ~ ~~~ ~ t~ ~ ~ 4 ~~~ tom;. p ~~ 'ham ~5.,~ ,~ - 5 ~ ` S ~ 3 {~ ~ , R~ ~ ~ ~ ~~. ,~ , ~ w.., ~ ,.; t `'. ~ a ?~ }., * ~ ~" is ,~ .. ~,.. ~... ~ ~~ ~~ ,;t z ,~ . ;.: ~,. ~ R ~, ,+ 1 ` +M\, .. ~\ `~~A~ ~ j~T~ 7,t `~F' w t _ ~i ,¢ ~a ~ q ~1Y. 1 ~ 1 ~~rn~V~r ,e, _~ ti ~` F ~ ~ ~. 3 ~ y. ~. ` :~ ; ~ ~ ~ ~ ~ ~,. ~, ~~ ~; ,~: ~+.`~ L =. ~~ f: ~, ` t ~~ E ~ ~~~~ _"~ Y?1 , ~, "~ ..~r 20676621 70 '.. # t'i , i P PhOtO 2 ,~ i'- ~ ~` `~ ~ SEC ~ $ 2006 ,I ~~ ~. 20676621 70 # ~2 ~ i ~~ 4~ s } k ~~ ~. ~ ,~,~ ~---_----~.~., ~, ~~~'a ~~ ~ l ~ . ~' ~ `~~; t~~G 1 ~ 2006 e. ..._. ;2097662170 # X31 18 operty Coastal Zone Atias, an;ty Jefferson County - Geology ,~: . nn .. ^-- ~, ` ~r X ~ 5 ~ ' ~yc76Sr Nei Qb. '~ r-~ i g ~ ~ ~~ ~ ~ ~~ ~. ' t - v ' 1 .._ , , - -- Qos _. Property Vicinity 20676621 70 # i4ft 8 I, i ',1. i Coastal Zone Atias, ',~ Jefferson County - ~ 1. ~~~~ ~ ,, ..,~ +,, I'3' -N~'~'Ih~An31K4e~~ltn:arcs - ~;` ` ~+4 ~ -Uds Yadr : '' ! ^~ ~ • .. ` 1 "` .~ 'Y° tai' ~1. ' f rte. ~ , .` ~. '~ j~ '` ' "~ SCwlh ~K+s~4 crvtsi aegd °~ i. _...,....-,~,.~.~. "may'-.~---~"'~ k ~~~~~ I t ~ , a _.~.._---- ,~ ~' Sri C~ss p~} ~(~, ~,,; ', ~ Ll~ f O ~OV~ _,,, ._ ~ ~.~.., - i 67662170 # T5~ i a ~ ~~~ ~~ ~ ~~, ~[ ~r ~~ ~ ~ ~ DEC 1 8 2006 ~ ~ ~~ ,~ ,~ -~ a ~~ ±~ ~a ^° t _ Y` 0 0 r Q ~. F ~~ iF ~~ 'L~ tr'rs. 4`i G L. ~ ~. •a Q i"J 1 .` ~. ~ r1IAP LEGENI3 MAP tNFUFtt~iA7'i4N ! i soli ar~up Cte~ Q ci:it9 Sourcz of 2~iap: t~Eatural Resourlre3 ~or}ssfVatlon Sen+ice u,l~r>,aet.:xy.~ Vtreb 8c9it Survey URL' ht!)5:I6~,~bs~iEsurvey.nres:usela.gov ~ -~-- rSuaUe: ~~:ti Caortlinafe Sy~tr31:1: ir"['PdZone 1a i ~`~"~` Soil &ulvey:~a: JeSfersan Cn~rtt~+Area,'JS~shin~tc ._. Hfr+,~r,a+r S~atial'~ers~n of 17ata- f ryxalex 3otl P~7ap Compttatr~tl Scale: t;~~ jr~rra L~er~rcxn:,8wlro.k w~w.mn Eicttgpsera, CJJat~IL 3'U:It ~ 44 . .. . ;lope ar fsovurc Gadpd Spx J k' ~tar' N a A 1 s e;; ~ ' .L CNavOky ESN.°S ti ~u~y It 1xSa Kuw i o fyncrle ~Y G1aee±ro ar Piaro:uup ~ P.fiilxYaraa~.sMistrx' P,49p E'Arfl~lrE34$'J Cf i1Gri2l ~12'12~.5 ptlatogt3ptlES! .~r1 ttt858 dat$s. v Ro~l7ttn•rop t1i17flg6Cl * .~1d~r~;J~f+1 sal~y e,~ t ~.7Wear SCp f ~' ~`1111111Ut9 .:(1(131:'Jt~i ~poilNra - ~ °Jrtry S; u4 Tlfe Q'IhOpfi9r66f 41,1r18f J85B trk'1fk 4f1 WhICh 1198 5411111111$ 9Ve.'8 C4ff1iJIIEd end V[Ay w:Vty ~:: digiEsaed probably differs from the 6a4k~tnund imagery dwt+faysd on 12fesa mays. • rer+zl~a1 na=.sr As a result some trnflor sl~nR;r1g of map unit b4undartes matt bs evxielal WW1.... . . ... ............. ..... .... ..__....._._.~,._.~...... _.___...r_. _._...~...,..._.......~.. .__.._..... ,.. . . 1V~1, ~ni1 ,`.lur3~c? r.l IhslikmgLC"~~:yrozrll.ive 5t1i1 tiallr~rti ._-'.3-06;11.: 24AM; BOEING intl sales ;2067662170 # 17,'1E r i ',+ui ~.;~~ey of Jel~soa Couuly Aaea, ~W''ashiagtnn Bodlcer Piroject' Map Unit Legend Summary i ~_r4:~t~ C~?~~c1iti~ .-1rea, ~'4'ashin~t~rti ~~tr-.a S3n~~l~al Map Unit 1Vame .4cres in .~O~C neru:nt of r1OC ~. b Aidsrtvood velly laud}* 1.5.0' 55.2 ~ _ laatn, U tca 15 p~-aent si~as } 7 "~ Bel Fast si.l.t;~ cla}~ laai~z, raet 53 I ~.=1 * " ~~a~iaaii Casaolary_Kitsap complex, l5 1.5 5.5 to 3~k percent stapes Coastal. Ueaclxes 1.3 6.7 ,''. ' K.itsap gravell~r loam, Q to lS 2..4 8.9 perce~Zt staples - -. 6;.-1~~24AM; BOE.I NG intl sales ;2067662170' # 18/ 18-