Landslide Hazard Assessment 02-16-06 001LETTER OF
TRANSMITTAL
GATE: February 16, 2006
SEND TO:
Ms. Tami Merriman
Assistant Planner
City of Yelm
PO Boz 479
Yelm, WA 98593
Vlp:
Hand Delivery
COPIES DATE DESCRIPTION
4200 61^ Ave SE, # 301
Lacey, WA 98503
360.493.6002 +°
360.493.2476 a
www.thescagroup.com
SCA PROTECT NUMBER:
05017
AGENCY P0.0JECT NUMBER:
PRWECT NAME:
FORRESTER HEIGHTS
THE SCA GROUP
~ 1 2/13/06 Landslide Hazard Assessment from Insight Geologic, PLLC
THESE ARE TRANSMITTED AS CHECKED BELOW:
® FOR YOUR USE ^ R$ REQUESTED
^ FOR REVIEW RCOMMENT ^ APPROVED pS NOTED
^ FOft YOUR APPROVAL ^ RETURNED FOR CORRERIONS
REMARKS:
As previously faxed to your office.
TMNSMITTED BY',
Nancy Connell, Executive Assistant to CEO
cc: File
k'E6.15'2070 02:31 360 7549240 Bristol Gt Services #3332 e. 002/003
INSIGHT GEOLOGIC, PLLC
Febmaty 13, 2006
SCA Consulting Group
4200 - 6a Avenue SE, Suite 301
Leery, Washington 96503
Attention: Steve Chamberlain
Landslide Hazard Assessment
Proposed Forrester Heights Subdivision
Tax Lot 2172513030
Yelm, Washington
INTRODUCTION
Insight Geologic, PLLC is pleased to provide this assessment of the slope along the
northeast portion of Thureton County tax lot 2172513030, in Yelm, Washingmn. The site is
located at 15026 State Highway 507 and is pending subdivision for a residrntial development
The parcel eocompaaces approximately I I acres. The eastern portiin of the property slopes
down form an elevation of approximately 440 feR above mean see level (MSL) to about 360
feet MSL bated oo the U.S. Geological Survey 7.5 minute McKemu topographic quadrangle
and on information obtained from the Thurston County Creodata Crnter.
The City of Yehn Critical Areas Ordinance identifies a landslide hazard area as a slope
being steepen than IS percent having intersecting geologic corrects with relatively permeable
sediment overlying impermeable sediment or bedrock, artd exhibiting springs or ground water
seepage, or, slopes grrnter than 40 percent
Insight Geologic evaluated the slope by conducting a site recomraissence and observing soil
conditions on the face, measuring the slope in aeveml locations using a hand-held elinommer
and by reviewing logs of soil test pits excavated on the site. Our reconnaissance of the alvpe
did not reveal Me presence of springs, seeps or hydric vegetation. The slope is vegeuted
primarily with grans, scotch broom aml with Douglas Fir trees along the sou0tem portion. The
trees appeared to have straight trunks and did not exhibh bowing that may ba observed on
instable slopes. Our measurements of the slope ranged between 30 and 37 percerrt, which xre
in grnerel agreement with our review of topographic information. Test pits conducted by SCA
Consulting Group on the upland portion of the site indicated rho presence of up to 3 feet of
sandy gravel overlying drnse, glacial till.
Based on ow review of Oro sitq and our understendmg of Yehn's Critical Areas Ordinance,
it does not appear that the slope along the eastern portion of the subject site meets the criteria
fvr a landslide bezard area.
Ia01sMr Geo~a0lc Rle
2401 asa]o4 Camr SW
OLVMVI4, W4sniacIDS 98502
2eoxe~ ]00.]54.2128 Foxe }00.]54.4210
FEH. 15'2000 02:32 369 7599290 Bcstel Ct Services p3332 P.003/C93
SCA Consulting Grwp
February 13, 2006
Page 2
We trust this letter meets your cur[ent requirements. Please contact us if you have
questions regarding our evaluation, or if you require additional information. We appreciate Ne
opportunity to be of service to SCA Consulting Grnup on this project
Respectfully,
INSIGNT GEOLOGIC, PLLC
William E. Halbert, L.G.. L.E.G.
Principal
IN6i6NT OEOLO6~C. PLLC
FAX
rAx TO: Ms. Tami Merriman
Assistant Planner -City of Yelm
rAx NO: 360.458.3144
FAX FROM: 360-493-2476
RE:
Landslide Hazard Assessment
AGENCY PROTECT NUMBER:
VRO]ER NOME:
FORRESTER HEIGHTS
4200 6NAVanup SE, Sulle 301
Lacay, WA 88503
360.493.6002 Phane
360.493.2476 FaE
www.theacagrouD•cpm
F.CiI
I
TXE SCA~,nP
scA rao]ecT Nuneea:
05017
PATE:
February 16, 2006
NUMBER OF PApE3:
3
®A HARD COPY WILL Bf
MAILED.
^ A BARD COPY WILL NOT BE
MATTED.
REMARNF:
Transmitted herewith please fled the Landslide Hazard Assessment dated February 13, 2006,
preparetl by INSlght Geologic, PLL[. Thank you.
YRANSMrnED ev: Nancy Connell, Executive Assistant to CEO
<c: File
TMZ facalmlle may concaln <onfleential, pmileeatl inprmaean'm[eneee pnlY for Ne Inelvleual or entlry co whom ¢ Is eeeressee. Da not
react, mpy or aizumina[e Nis Informanon unless you aR [h<deerc£Set (or Me ptrsan responsible br eelivennp iq. IE you nave receives
[MS communl[atlon in ertor, please return Ne anginal mmmunlotlon to 5CA Conzul[Ing Group ela fnt poatal sorvlCB. Mellln9 Ws[S will be
reimW:zee. TLank you.
FE°/.F i r /"=U iJ'~,!I A11 5CA a,. P.'o. 3Ff ~ ~47F~ N. S_iC
k SH. 15'2000 02:31 360 7549290 arie<ol CC Servicee Y3332 P.002/003
INSIGHT GEOLOGIC, PLLC
February 13, 2006
SCA Comulting Group
0.200 - 6a Avenue SE, Suite 301
Lacey, Washington 98503
Attention: Stove Chamberlain
.Landslide Hazard Assessmrnt
Proposed Forrester Heights Subdivision
Tax Lot 2172513030
Yelm~ Waslungtoi
INTRODUCTION
insight Geologic, PLLC is pleased to provide this esaeasmrnl of the slope along the
nortbeast portion of Thurston CowTy tax lot 21725130?0, in Yelm, Wsshingmn. The site is
located at 15026 State Highway 507 and is pending subdivision for a residen[ial devalopmaM.
The parcel enrompasses approximately 1 ] acres. The eastern portion of the property slopes
down from rn elevation of approximately 460 feet above mean sea level (MSL) to about 360
feet MSL bayed oo the U.S. Geological Swvry 7.5 minute McRamw topographic quadrangle
and oa information obtained from the Thurston County Geodam Center.
The City of Yohn Critical Areas Ordinance identifies a landslide hazard area ns a slope
being steeper than IS perernt having intatroodng geologic rontaots with relatively permeable
sediment overlyiog impermeable sediment or bedrock and exhibiting aptings or groind water
seepage, or, slopes g~tcr than 40 percent
Insight Geologic evaluated the slope by conducting a slm rucoannissance and obacrviog soil
conditions on the face, measuring the slope in several loadoae using a hard-held clinometm
and by reviewing logs of soil fast pits excavated on the silo, Our raconaaissaopo of the dope
did not raved rho presence of sprbsgs, seeps or hydric vegefatlon. 1Ile slope is vegeated
primarily wJth grass, scotch broom and with Dougtac fu trees along the southern portion. The
trees appeared to have straight trunnle and did not exhibit bowing that may 0.a observed on
unsreDle slopes. Our meanuvoents of the slope ranged between 30 and 37 percert, which are
in geaeml agreement with our review of Wpographic information. Test pib conducted by SCA
Consu]tiog Group on the upland portion of the site iadiated the presenoa of up to 3 feet of
sandy gavel overlying densq glacial till.
~'~ Based on o9¢ review of the sitq and our uadasmnding of Yehn's Crieical Areas Ordimnce,
it door not appear that the slope along the csstem portion of the subject site meats the criteria
for a landslide hazard wren.
IanrNr Grmoo~G Rlp
LAW aarero~ CDYRT Stu
pgwru. WNeniNOraN 10602
MoN1: 300.]a~.21$a F~¢ 300J3~.GriD
?6/'%~!% ..::J 0~',L_ A`.. SCA ~A%Pla.3ff 431 ~^7fi F,~i~'~
_ CHH. ),p l~[u VV Ul:3L 3BV 'r>99 L9 V. B[istol Gt Se[vices ;33?2 P. 003/003
SCA Consulting Grcup
Fabrunry 13, 2006
Page 2
Wa wst this letter meets your curteut requiremm[s. .Pleats corrtect us if you havc
questions regarding our evaluation, or if you requ[tu additional information. We appteoiete the
opportunity to be of gervica to SCA Cmsvltitla Grwp on this project.
Respectfully,
tpslsnr GEOloctt. PLLC
WilGmn E. Halberq L.G., L.E.O.
Principal
Iacicar aeolo •~c. PLL[