HomeMy WebLinkAboutGEO2013-00004 Relocate Winter Creek - GEO Geological Review - 12/30/2012' Lilliwaup Falls Power Project RECEIVED
JAN 15 2013
Geotechnical Report for the 426 W. CEDAR S7.
Winter Creek Channel Relocation at
Lilliwaup Falls
December 2012
Prepared by:
JACOBS ASSOCIATES
Engineers/Consultants
Jacobs Associates
1109 First Avenue,Suite 501
Seattle,WA 98101
Distribution
To: William G. Reed,Jr.
Lilliwaup Falls Generating Co.
Craig Norsen
Seneca Real Estate Group, Inc.
From: Frank Pita,P.E.,L.H.G.
Jacobs Associates
Prepared By: Sue Bednarz,L.G.
Jacobs Associates
Frank Pita,P.E.,L.H.G.
Jacobs Associates
Maureen Kwolek,P.E.
Jacobs Associates
Reviewed By: Frank Pita,P.E.,L.H.G.
Jacobs Associates
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Jacobs Associates -11- Rev. No. 0/December 2012
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Lilliwaup Falls Power Project Geotechnical Report: Winter Creek Channel Relocation
1 Introduction
1.1 Background
In January 2006 a landslide destroyed a portion of the concrete flume that conveys water from the intake,
above Lilliwaup Falls,to the penstock of the Lilliwaup hydroelectric facility,a privately-owned
hydroelectric generating plant located on Lilliwaup Creek,Mason County.At about this same time
Winter Creek,an ephemeral(non-perennial)Type F stream that discharges into Lilliwaup Creek near the
intake area,overtopped its banks and relocated adjacent to the hydropower facility intake,cutting a new
channel through an access/parking area. Figure 1 is a Vicinity Map of the project area.
Following the landslide,and the after the creek relocation,diverted stream flows were no longer
conveyed to the powerhouse and power generation ceased.The proposed project"Lilliwaup Falls Power
Project"will restore hydropower generation at the Lilliwaup hydroelectric facility by:
• Repairing the landslide by constructing an engineered fill that will support a new conveyance
pipeline that replaces the old concrete flume,
• By constructing a new access road to the intake area,and
• By relocating the Winter Creek channel away from the intake structure.
The other components of the hydroelectric system will remain and the intent,as we understand it, is to
operate the facility as before.
This Winter Creek Geotechnical Report is ONLY for the Winter Creek channel relocation portion of the
Lilliwaup Falls Power Project. Another geotechnical report"Lilliwaup Falls Power Project,
Geotechnical Report for the Landslide and Conveyance Pipe Repairs", (April 2012)was already
submitted to Mason County for the landslide restoration,and new pipeline and access roadway portions.
Some of the data presented herein is also presented in the April 2012 report.
As a note, Winter Creek has its name because stream flow in the creek is only visible during the winter
when it is raining heavily. This typically means that rain is the major source of the creek's water and it
flows only during the wet time of the year.
1.2 Project Overview & Geotechnical Report Purpose
The Winter Creek Channel Relocation Project,as we understand it,is as follows:
• Relocate approximately 100 lineal feet(If)of the existing Winter Creek channel by moving it
westward up to 25'.
• The location where Winter Creek ends and then enters into Lilliwaup Creek will remain at the
current location.
• New channel bottom will vary between 8' and 12' in width.
• New channel will be armored along the east bank for a length of approximately 1001f,using 3-to
4-man angular rockery stones. This rock will be placed at approximately a 1:1 (horizontal
vertical)slope. The armor rock will be underlain with quarry spalls and a filter fabric.
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Lilliwaup Falls Power Project Geotechnical Report: Winter Creek Channel Relocation
• The west bank will be laid back at approximately a 3:1 (horizontal:vertical)slope into the native
soil,and replanted with native vegetation that replicates a natural,undisturbed riparian condition.
Some scour and deposition is anticipated to occur along this bank.
• Approximately three(3)grade control rock weirs,6' in width,will be located across the channel
bottom to control potential downcutting during high flows. Weirs will be constructed of 2-man
round rocks.
• Backfill the existing channel(approx. 1001f)to restore the access/parking area.
The purpose of this geotechnical report includes the following:
• Identify site conditions related to channel side slope stability.
• Provide geotechnical design parameters and recommendations for the following relocation tasks:
o Temporary cut slope angles,
o Construction material compaction recommendations,and
o Foundation design pressure for blocks or large rocks.
This report provides the geotechnical recommendations for earthwork construction,as well.
The detailed plan view of the project and the channel cross sections are presented in Appendix A on two
of the construction drawings.
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Lilliwaup Falls Power Project Geotechnical Report: Winter Creek Channel Relocation
2 Site Conditions
The following is a summary of site conditions at the lower end of Winter Creek where it meets Lilliwaup
Creek.
2.1 Topography and Geomorphology
The project site is located entirely above Lilliwaup Falls in the northwest quarter of Section 19, T 23 N,R
3 W(WM)in Lilliwaup, Washington. At this location,the gradient of Winter Creek is nearly flat as it
meets Lilliwaup Creek. The hydropower facility intake is also at this location.
2.2 Geology
The project area is located in the Hood Canal area of the Western Puget Lowland of northwestern
Washington. Both alpine glaciers from the Olympic Mountains and continental glaciers coming down
from Canada covered the Hood Canal area and deposited glacial sediments on top of the preexisting
ground surface. Within the project area,Vashon-age continental glacial deposits mantle the preexisting
irregular topography carved into the underlying basalt bedrock of the Crescent Formation. Glacial
sediments in the project area include(from oldest to youngest)Advance Outwash Deposits,Glacial Till,
and Recessional Outwash/Ablation Till. Both the Advance Outwash Deposits and Glacial Till were over-
ridden by the Vashon ice sheet and are therefore dense and overconsolidated. The Recessional Outwash
Deposit/Ablation Till is less dense and is normally consolidated.
Project area glacial sediments mantle the irregular basalt erosional surface except where the rock is
exposed at the waterfall. Along the Winter Creek channel,there is a thin layer of alluvium that either
overlies glacial deposits and/or the basalt bedrock in the vicinity of the confluence of the two Creeks.
Figure 2 depicts a geologic map of the Lilliwaup area showing bedrock outcrops and glacial units.
Figures 3 show the site specific geology of the area and it is a product of the onsite mapping and the
borings.
2.3 Local Landslide Activity
The steep slopes underlain by glacial deposits in the vicinity of the Lilliwaup Creek and Falls area are a
common host for landslides,especially after episodes of prolonged and significant rainfall. Figure 2
shows the locations of mapped landslides in the vicinity of the project area. The failure mechanism for
the majority of these slides is thought to be a reduction of the stability of glacial soil due to the
development of perched groundwater on top of an aquitard such as glacial till or bedrock(Shipman,
2001).
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Lilliwaup Falls Power Project Geotechnical Report: Winter Creek Channel Relocation
3 Site Investigations
Site investigations for the Lilliwaup Falls Power Project included both surface geologic mapping of the
landslide area,the hillsides,and a subsurface geotechnical investigation that included drilling five(5)
borings in the vicinity of the landslide and Winter Creek. The purpose of these investigations was to
characterize surface and subsurface conditions to provide input for geotechnical design.
3.1 Geologic Mapping
On February 24 and 25,2006,surface geologic mapping was conducted in the vicinity of the landslide
and Winter Creek to identify soil and rock units,delineate the limits of the landslide,and identify
locations of groundwater seepage and springs. Locations and elevations of geologic features were
estimated using a handheld laser rangefinder,clinometers,and compass. Site geology was recorded on a
site plan and cross sections were developed that identify geologic contacts and estimated groundwater
levels. This earlier data was combined with recent geologic mapping in 2012. A summary of this
information,along with published data, is presented on Figures 3 and is discussed in Section 4 of this
report.
3.2 Subsurface Investigation
In 2006 five borings(MP-1 through MP-5)were drilled above the headscarp of the landslide and along
the existing intake access road that extends down to Winter Creek to obtain information on subsurface
conditions,including soil engineering properties,depth to bedrock,and groundwater levels. The boring
locations are shown on Figure 3 and boring logs are included in Appendix B.
The borings were drilled to depths ranging from 9 feet to 95 feet using solid stem auger drilling methods
and a track-mounted drill rig operated by Holocene Drilling of Puyallup,Washington. Each boring was
advanced through glacial soils down to basalt bedrock. Two of the borings were installed with standpipe
piezometers to permit groundwater level monitoring. Borehole soils were logged by a geotechnical
engineer. Soil samples were collected during drilling for possible laboratory testing.
3.3 Laboratory Testing
Three grain size distribution tests were performed by Cascade Testing Laboratory,Inc.,on selected
borehole samples for soil classification and to evaluate the engineering properties of site soils. The
borehole glacial soils included well-graded to poorly-graded gravel with silt and sand(GW-GM to GP-
GM),silty sand with gravel(SM),and well-graded sand with gravel(SW).
This laboratory data from 2006 are presented after the boring logs in Appendix B.
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Lilliwaup Falls Power Project Geotechnical Report: Winter Creek Channel Relocation
4 Subsurface Conditions
The following discussions of the estimated subsurface conditions within the project area are based on
surface and subsurface conditions identified during the geotechnical investigation and published geologic
mapping.
4.1 Rock (Eve)
Basalt bedrock of the Crescent Formation(geologic map symbol Eve)was encountered in the project
borings and is exposed along the east flank of the landslide,along the Lilliwaup Creek canyon walls and
underlies the falls(Contreras and others,2010). The basalt within the project area is relatively
unweathered,strong,and relatively resistant to erosion. The upper surface of the basalt bedrock controls
both the location of the falls and constrains groundwater movement. Basalt bedrock underlies the glacial
sediments in the project area and is not expected to be susceptible to slope failures. The location of basalt
bedrock in the project area is shown on Figures 2 and 3. Basalt bedrock was encountered at variable
depths within the project borings, indicating the presence of an irregular erosional upper contact. .
4.2 Soil
The project area is underlain by glacial soils including Advance Outwash Deposits,Glacial Till,and
Recessional Outwash/Ablation Till. Alluvial soils are present in the vicinity of Winter Creek,but are not
located within the planned landslide repair. Figure 3 shows the mapped location of the glacial soil units
within the project area.
4.2.1 Advance Outwash Deposits (Qva, Qgo)
Advance Outwash Deposits(geologic map symbol Qva or Qgo)overlie the basalt in the vicinity of the
project area. These deposits consist of dense, stratified,well-graded sand with gravel,sand with gravel
and cobbles,and poorly graded fine and medium sand. The silt content is generally low(less than 5 to 10
percent). The Qva soil is overconsolidated and relatively strong. This material may be the source of the
alluvium that is present in the Winter Creek work area but it has been reworked and brought down the
channel to this location.
4.2.2 Glacial Till (Qvt, Qgt)
Glacial Till(geologic map symbol Qvt or Qgt)overlies the Qva in the vicinity of the project area and is
exposed along the landslide headscarp above the Qva. Glacial Till consists of dense, unstratified,silty
sand with gravel. The Qvt is an overconsolidated soil that is relatively strong and has a low hydraulic
conductivity(permeability). The Qvt is expected to act as an aquitard to rainwater infiltration and limit
groundwater flow into the underlying Qva unit. This unit does not appear to be present in the Winter
Creek project area. It may be present further up the watershed.
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Lilliwaup Falls Power Project Geotechnical Report: Winter Creek Channel Relocation
4.2.3 Recessional Outwash/Ablation Till (Qvr, Qgr)
Recessional Outwash/Ablation Till(geologic map symbol Qvr or Qgr)overlies the Qvt in the vicinity of
the landslide. Qvr consists of well graded sand with gravel and gravel with sand. The Qvr is exposed in
the upper part of the landslide headscarp and flanks and is also exposed in road cuts above the slide. The
Qvr is relatively permeable and permits rainwater runoff infiltration. Perched groundwater levels are
expected to form in the Qvr on top of the relatively impermeable Qvt soil layer. This unit may also be the
source of the Winter Creek Alluvium because it is present further up the watershed.
4.2.3.1 Stream Alluvium (Qa)
Winter Creek,as well as Lilliwaup Creek,have eroded material from further up the drainage basin and
moved it to the area around the confluence of Winter and Lilliwaup Creeks. This material appears to be
all reworked glacial soils. The composition is mostly coarse because of the high energy environment that
it was deposited in. This material should be considered a sandy Gravel to Gravelly Sand. The stream
relocation will be mostly within this unit.
4.3 Groundwater
Groundwater in the project area is derived from infiltration of precipitation in the watershed and access
road runoff into permeable Qvr and less permeable Qva aquifers. Following infiltration, groundwater
migrates downslope toward the Winter Creek alluvium in the upper watershed within Qvr and Qva along
aquitards formed by relatively impermeable Qvt soil and basalt bedrock, respectively. During significant
rainfall events, perched groundwater is expected to form within the Qvr and Qva units, reducing the
stability of this unit in watershed sides slopes but they are all upstream from the project area.
Groundwater levels within alluvial soils are completely controlled by the amount of water trying to flow
down the watershed of Winter Creek. During the dry times of the year,the flow is so low that there is no
visual flow seen in the channel and the groundwater table is below the creek's channel surface. However,
during high precipitation times,the channel has visible flow and the groundwater level in the watershed is
higher.
Groundwater levels on the intake access road to the east of Winter Creek and west of the landslide and
were measured at Elevation 327.5 in October 2011 and Elevation 329 in March 2012.
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Lilliwaup Falls Power Project Geotechnical Report: Winter Creek Channel Relocation
5 Engineering Analysis Discussion & Recommendations
The following is a discussion of the engineering analysis and evaluations conducted for the Winter Creek
Channel Relocation project.
5.1 Global Stability of the Valley due to Channel Change
The stability of the Winter Creek valley side walls are not affected by this relocation project. This work
is not close enough to the sides to result in undermining or a change in the groundwater conditions.
5.2 Temporary & Permanent Cut & Fill Slope Angles
As can be seen in the attached photos,the materials are coarse and they will stand at a steep vertical angle
for a long period of time. Therefore,the proposed 1 H 1 V slope for the armor stone should be stable.
Also, since the cut is less than 3 feet, it does not fall under the WISHA regulations.
5.3 Foundation Support
The coarse sand and gravel, when in its compacted state is quite strong and can support the proposed
armor rocks. The bearing capacity exceeds 3000 pounds per square foot. This material will also support
autos and other machines performing work at the intake.
5.4 Earthwork & Compaction Control
The site material, as can be seen in the photos and the grain size results, is almost entirely a coarse SAND
and GRAVEL. As a result, because there are so few fines a moisture—density type test(Proctor) is not
applicable to the material. Instead,the material must just be placed to a dense, non-yielding condition at
the direction of the Resident Engineer. The lifts should be placed in a near horizontal condition and no
thicker than 12 inches.
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Lilliwaup Falls Power Project Geotechnical Report: Winter Creek Channel Relocation
6 References
Contreras,T.A.,Legorreta Paulin,Gabriel,Czajkowski,J. L., Polenz,Michael,Logan,R. L.,Carson,R.
J.,Mahan, S.A.,Walsh,T.J.,Johnson,C.N.,Skov,R.H.,2010,Geologic map of the Lilliwaup
7.5-minute quadrangle,Mason County, Washington: Washington Division of Geology and Earth
Resources Open File Report 2010-4, 1 sheet,scale 1:24,000,with 13 p.text.
[http://www.dnr.wa.gov/Publications/ger_ofr2010-4_geo1_map_lilliwaup_24k.zip]
Shipman,H.,2001,Coastal Landsliding on Puget Sound:A review of landslides occurring between 1996
and 1999: Washington Department of Ecology Shorelands and Environmental Assistance
Program Report#01-06-019,August,2001.
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Lilliwaup Falls Power Project Geotechnical Report: Winter Creek Channel Relocation
Photos & Figures
Pr `1 J_' Gyi3al ;t9.
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Photo Log:
I. Looking from intake upstream at Lilliwaup Creek where
Winter Creek ends. This is proposed(and existing)location
of the confluence of the two creeks.
2. Photo of Winter Creek looking downstream toward intake.
The`ecology'block wall in Photo#1 is in the far distance
,t (arrow). Channel relocation is to move this section to the
-. right in the photo.
J � 3. Looking upstream from intake area at Winter Creek channel
I ' that will be relocated to the left in this photo.
4. Standing further upstream from intake area at edge of Winter
3 ~" Creek. Channel will be relocated from bend(arrow)that is
T_ e
just in front of SUV toward the left side of photo to where the
creek currently enters Lilliwaup Creek(photo#1).
View of Winter Creek from bank just in front of where SUV
z,. 'o o o is parked in Photo 4. Note material in channel walls is SAND
&GRAVEL.
Jacobs Associates Rev. No. 0/December 2012
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Lilliwaup Falls Power Project Geotechnical Report: Winter Creek Channel Relocation
Project Area
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Li6weup Creek Residence
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Jacobs Associates Rev. No. 0/December 2012
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Lilliwaup Falls Power Project Geotechnical Report: Winter Creek Channel Relocation
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Figure 2. Lilliwaup area geologic map showing project area landslide located within the red circle(after
Contreras and others 2010). Note the presence of numerous other landslides(Qls)within glacial soils the
Lilliwaup area. (See Section 4 in the text for a description of the geologic units within the project area.)
Jacobs Associates Rev. No. 0/December 2012
CSC � 13
TO SCHOENING
EXISTING INTAKE _ r RESIDENCE
ACCESS ROAD A
APPROXIMATE
4 CLEARING LIMITS 40 0 40 80
FEET
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/ A CUT/FILL SLOPE
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1 J "'• - ���� \ .` LANDSLIDE LIMITS Qu<=Glacial Till
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Basalt=Basalt Bedrock of the Cresent Formation
/ A'I II MP-3 _ \ \� Qa=Winter Creek Alluvium
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O WINTER CREEK �� l - ) � � Landslide Limits
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Lilliwaup Falls Power Project Geotechnical Report: Winter Creek Channel Relocation
Appendix A
Plan & Sections from Civil Drawings of Proposed Winter
Creek Channel Relocation plans
Jacobs Associates Rev. No. 0/December 2012
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NOTES: LEGEND:
_ MATCHLINE SEE BELOW
/—7 /�� / O EXTEND
I CHANNEL.SETP PIPE AT BOTTOM OF NEW CHANNEL.SLOPE PIPE O
- wo -- - EXISTING TOPOGRAPHY-S CONTOURS
DRAIN.JOIN NEW PIPE TO EXISTING VMTH COMPATIBLE STEEL COUPLING.
/ OD END/NEW C NEL / / �� / /�/ , / - — — — - EXISTING TOPOGRAPHY-I'CONTOURS
/ / / // / 2O LOCATE AND EXCAVATE BURIED(EAST)ENDS OF 18"CMP AND 4"CPEP.REMOVE 5
4"PIPE IF POSSIBLE.CLEAR ALL DEBRIS FROM INSIDE PIPES.INSTALL CATCH PROPOSED ELEVATION
24" CEDAR — _ BASIN OR INLET AS REQUIRED TO INTERCEPT FLOW AT UPSTREAM END OF
10 / 0 1— PIPES.COORDINATE WORK WITH ENGINEER. EXISTING CREEK CHANNEL
USE EXISTING SCATTERED ECOLOGY BLOCKS TO REPAIR/REINFORCE THE BACK
OF THE EXISTING BLOCK WALL.INSTALL APPROXIMATELY 16 LF OF WALL ALONG ® ROCK ARMORING
FEET THE BACK OF EXISTING WALL,3 TO 4 BLOCKS HIGH.EXCAVATE NEW WALL
SECTION TO THE SAME DEPTH AS EXISTING WALL.TOP ELEVATION OF NEW 3
30" CEDAR BLOCKS SHALL MATCH THE EXISTING WALL. ROCK DROP STRUCTURE e
18 ALDER
TNLS /
# 17 I`� C � / / -- � �/ __ // NORTHING FASTING STATION
/ _ I
3O ROTECT EXISTING / OA 790639.8220 992216.4954 0+00.00LEAF
TNLS# 19 CLEANERS //j O 790700.5639 992234.6597 0+63.40
\ C 790729.1570 992229.3870 0+92.47
790754.9445 992247.1711
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\ \\ �EDFA R
GRAVELb / I
/CUT ChAWNEL BANK
STEEPER TO PROTECT I \\ IE 18" CMP�= 321.2
EXISTING TREES I Z� \\ / \ / -361-H A� '/w,
s -
/ 18 F _ \ \ 2
r NLS 1
13" /CEDAR \\�A / E DES INT9 BA`N\ \ \ \ / \� �/ // / _ _\ \ — � i / 9 / // 48" CEDAP
F / / / / I 1 \ 48 MA\PLE
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323. I I4 C P\IE 3 ✓2 IE (Ek F1= TI�N�E \A 2.0
DAR 3 / /3CE 3
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4/8" CEpAR /APPR r I I
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APPROX. TOP OF I I // / / / I v I •I
_ GRAVEL = 311.5 j/ / I / / ! / z I I
/q� APPROX. INTAKE STRUCTURE — / / I / / ' / / / I
k pll / LOCATION EXISTING ECOLOGY
OF KELLY i3LK WgLL BLOCK WALL TO REMAIN
FRONT EDGE OF / / // / -330-
LILLIWAUP CREEK
BEGIN NEW CHANNEL qO
APPROX. LOCATION OF CONIC WALL
_ AT TOP OF WATER FALL
[ FOR PERMIT REVIEW now what's below.
MATCH EE AB VET- - 1 I 'Call before you dig.
DESIGNED: CHECKED: DATE:
S.MORALES M.KWDLEK LILLIWAUP FALLS POWER PROJECT DECEMBER 21,2012
WINTER CREEK CHANNEL RELOCATION AT LILLIWAUP FALLS JOB NO:
JACOBS ASSOCIATES DRAWN: APPROVED: 4435.0
rs D.LILLY F.PITA DRAWING NO:
Engineers/Consultants HORZSCALE: VERTSCALE: CHANNEL LAYOUT&GRADING PLAN e
No- REVISION BY APP'D
1"-10'-0" 1"-19-0" HEFT NO: OF
8 11
340 340
STIP IG TOI I OF E ANK
PF tOPOSED CI iANNIL EXISTING C HANN EL
RE OCA ON O RE IN
P PO DC N TO OF K ISTI GG E CE TERLNE ---- -- -- — -- -- — -- --
F EXI TING CHA NEL _
330
320 /
320
PRO OSEE CHA NEL WES EDG
PROOOSEE CHAI INEL EAST EDG
31. IT
b S 3 e S 3 0
WINTER CREEK PROFILE
SCALE: HORZ 1"=10'-0",VERT 1"=V-0" 10
B
328 328
A 326 3za I LL1 I BANK BANKFULLSTAGE
B
324 KEY BANK KEY
co I MEAN LOW WATER
STA 0+15.00 322 - - - 322 w
320 _ _ - - - 320 A A Q
31a R o o ^ Y 318 Y Y CHANNEL BED
m Y w SECTION A-A PLACE ROCKS ON BED
J
WITHOUT EXCAVATION
BACKFILL EXISTING
PROPOSED(TYP) CHANNEL(TYP) UP
LOEXISTING(TYP)330 330 2-MAN ROUND
GRANITE ROCK3za 3za LUNGE w a
_ POOL =>
326 _ - _ - _ 326 �B
8
324 324 IL WIDTH VARIES
STA 0+50.00 r ^ BEDLOAD DEPOSITED
azz _ _ 3= PLAN VIEW AGAINST STRUCTURE
SECTION B-B
320 320
� ROCK DROP STRUCTURE
SCALE: NTS 10
----- ----- -------------------------------------
330 330 3
1 1
328 _ _ - - 328 8'TO 12'PER PLAN
3-TO 4-MAN ANGULAR 5 0 5 10
C 326 326 GRANITE ROCK
B
324 324 ••• •-•-- -------- BACKFILL AND COMPACT
STA 1+00.00 - - _ _ REPLANT SIDE SLOPE WITH FEET
322 322 NATIVE VEGETATION-SEE \ EXISTING CHANNEL WITH NATIVE SOIL
RESTORATION PLAN �
320 3zo FILTER FABRIC
EXCAVATE TO MIN.24"BELOW GRADE , 1 c
NEW GRADES — MIN 1'THICK FILTER LAYER OF
QUARRY SPALLS 6
TYPICAL CHANNEL SECTION w what's below.
SCALE: NTS STA0+11 TO STA 1+25 10 FOR PERMIT REVIEW Kn Cell before you dig.
DESIGNED: CHECKED: DATE:
S.MORALES M.KWOLEK LILLIWAUP FALLS POWER PROJECT DECEMBER 21,2012
Qa Nr WINTER CREEK CHANNEL RELOCATION AT LILLIWAUP FALLS JOB NO:
DRAWN: APPROVED: 44350
=o D.LILLY F.PITA DRAWING NO:
No. REVISION BY APP'D Engineers/Consultants HORZ SCALE: VERT SCALE: CREEK PROFILE&CROSS SECTIONS SHEET NO:9
OF
1"=t0'-0" 1 5'-0""=
9 11 i
kX19- �j 17
Lilliwaup Falls Power Project Geotechnical Report: Winter Creek Channel Relocation
Appendix B
2006 Boring Logs and Laboratory Testing from Boreholes
■
Jacobs Associates Rev. No. 0/December 2012
Milbor-Pita DRILL HOLE LOG
ASSOCIATES,M. Boring No.: MP-1
Project: Lilliwaup Hydro Project Landslide Project No.: 1577
Client: Liliiwaup Hydro Project Date Drilled: 4-11-06
Location: Turnout at top of Slide Elevation: 415
Driller: Holocene Logged B
99 Y: CAR
Drill Rig: Track Rig
Depth to Water: Date: 4-12-06 Depth: 95, Date: T Depth:
Elevation " Test Results
Welland a°' U Q
Depth(Ft.) Detail Description Z NM SNT Moi NrValue •
Value
0 _ = GM Loose to medium dense,brown,silty fine to 3
SMGM-
coarse SAND and fine to coarse GRAVEL
_ , = SM
400 = —
20 —
380 —
40
GM- Becoming denser t
380 — = SM
80 =
GM-
SM
340
eo
GM-
320 SM
GM- End of Hole at 95 R depth. '
100 SM
300
120
s
280
This information pertains only to this boring and should not be interpreted as being indieitive of the sits.
Figure PAGE 1 of 1
Milbor-Pita DRILL HOLE LOG
&7C1ATES,INC. Boring No.: MP-2
Project: Lilliwaup Hydro Project Landslide Project No.: 1577
Client: Lilliwaup Hydro Project Date Drilled: 4-12-06
Location: 170ft down road from crest of hill towards intake structure. Elevation: 394
Driller: Holocene Logged By: CAR
Drill Rig: Track Rig
Depth to Water: Date: NA Depth: Date: s Depth:
Elevation
o m Test Results
Well t
Depth Detail j Description co CL z NM SNT Moisture
p Value SPT N-Value s
10 30 50
0 Gw- Brown,fine to coare SAND and fine gravel.
SW
390 ;
5
3a5
to
�.4
I
Gw- End of Hole at 14 fi depth '
Sea sw
�s
375
20
370
25
365
30
360
This information pertains only to this boring and should not be interpreted as being indicitive of the site.
Figure PAGE 1 of 1
Milbor-Pita DRILL HOLE LOG
Boring No.: MP-3
Project: Lilliwaup Hydro Project Landslide Project No.: 1577
Client: Lilliwaup Hydro Project Date Drilled: 4-12-06
Location: 150 ft down road from MP-2 Elevation: 368
Driller: Holocene Logged BY: CAR
Drill Rig: Track Rig
Depth to Water: Date: sNA Depth: Date: Depth:
Elevation Well t w w Test Results
and
Depth(Ft.) Detail Description a Z NM SNT Moisture
Value SPT N-Value e
10 30 5
° 0 Brown,slightly coarse A SW g y gravelly,slightly fine to
medium sandy,slightly silty,coarse SAND and
fine GRAVEL.
A
3W--
to
M� i
ass
�i
is "y►�''
f►!t
350
345 Gw- End 0f Hole at 22.5 ft depth >50
Sw
25
340
30
335
This information pertains only to this boring and should not be interpreted as being indicitive of the site.
Figure PAGE 1 of 1
Milbor-Pita DRILL HOLE LOG
&SSOCIAITS,INC. Boring No.: MP-4
Project: Lilliwaup Hydro Project Landslide Project No.: 1577
Client: Lilhwaup Hydro Project Date Drilled: 4-12-06
Location: 70 ft down road from MP-3 Elevation: 359
Driller: Holocene Logged By: CAR
Drill Rig: Track Rig
Depth to Water: Date: sNA Depth: Date: Depth:
Elevation ° N d Test Results
and Det ail ff 3 Description z° SPT Moisture
Depth(Ft.) o N NM Value SPT N-Value •
10 30 50
0 GW- Brown, slightly silty, fine to coarse SANDY,
►:� SW fine to coarse GRAVEL
10
35s *�-
5 .:...
$W
via
350
GW- End of Hole at 9 ft depth
10 SW
345
15
340
20
335
25
330
30
325
This information pertains only to this boring and should not be interpreted as being indicitive of the site.
Figure PAGE 1 of 1
Milbor-Pita DRILL HOLE LOG /1177
&SSOCIATES,INC. Boring No.: MP-5
Project: Lilliwaup Hydro Project Landslide Project No.: 1577
Client: Lilliwaup Hydro Project Date Drilled: 4-12-06
Location: 66 R down road from MP4 Elevation: 340
Driller: Holocene Logged By: CAR
Drill Rig: Track Rig
Depth to Water: Date: `-z NA Depth: Date: Depth:
Elevation = coa Test Results
and Well 12 o U Description E o SPT
Detail � J U p m z NM N Moisture
Depth(Ft.) 0Value SPT N-Value •
10 30 50
340 0 = — �w- Brown,tine and coarse SAND and fine to
f Y:' GW coarse GRAVEL,
Sw
335 5 = = -
330 10 = Gw-
!: Sw
r
325 15
320 20 GW
End of Hole at 20 ft depth. >50
Sw
315 25
310 30
This information pertains only to this boring and should not be interpreted as being indicitive of the site.
Figure PAGE 1 of 1
KEY TO SYMBOLS - -
symbol Description Symbol Description 2-3
i
Strata symbols no pipe, filler material
Silty sand and gravel
i
Igo
Well graded gravel
and sand
Misc. Symbols
Boring continues
♦ Description not given for:
nFTRANGLE"
Water table during
drilling
TDrill rejection
Monitor Well Details
flush-mount
cover
8 bentonite pellets
slotted pipe w/ sand
❑ end of well
installation
i
Notes:
i
1. Exploratory borings were drilled on 4-12-06 using a
4-inch diameter continuous flight power auger.
2. No free water was encountered at the time of drilling or
when re-checked the following day.
3. Boring locations were taped from existing features and
elevations extrapolated from the final design schematic plan.
4 . These logs are subject to the limitations, conclusions, and
recommendations in this report.
5. Results of tests conducted on samples recovered are reported
on the logs.
Particle Size Distribution Report
100so
AEX
Hil
8o
70
Z LLJ 60--
U-
Z 50-- Ir
0
W 40--
30
20
10
01
500 100 10 1 0.1 0.01 0.001
GRAIN SIZE mm
%COBBLES %GRAVEL %SAND %FINES
CRS. FINE CRS- MEDIUM FINE SILT CLAY
0.0 0.0 21.9 12.2 16.5 16.9 32.5
SIEVE PERCENT SPEC.* PASS? Soil Description
SIZE FINER PERCENT (X=NO) Silty sand with gravel
.75 in. 100.0 W-1 Cuttings
.625 in. 97.2 Dated 4-13-2006
.5 in. 92.8
.375 in. 88.7 Atterberg Limits
#4 78.1 PL= LL= Pl=
#8 68.4
010 65.9 Coefficients
#20 56.2
040 49.4 D85= 7.39 D60= 1.24 D50= 0.453
#80 40.8 D30= D15= D10=
#100 38.4 CU= CC=
#200 32.5 Classification
USCS= SM AASHTO= A-2-4(0)
Remarks
As Received Moisture Content= 13.9%
F.M.=1.26
(no specification provided)
Sample No.: 6297 Date: 4-18-2006
Location: Elev./Depth: - 15'
Client: Milbor-Pita
Project: 2006 General Laboratory Work
CASCADE TESTING L-AEI0FRA-r(--DRY, INC.
TeErn"'o&fflisRacrrioN/ENGINEERS Project No: 06 1-22
le s NE 926TM
Technician: Nick Averill Inspector:
fa
E-x
Particle Size Distribution Report
5
.4 19 A
4 .2 V&
100
90
80
r I
70
Z LU 60-
LL
50
LU
Ui 40
30---
20
10
500 100 10 1 0.1 0.01 0.001
GRAIN SIZE- mm
%COBBLES %GRAVEL %SAND %FINES
CRS. FINE �. MEDIUM FINE SILT CLAY
0.0 5.3 43.5 23.4 13,6 5.9 8.3
SIEVE PERCENT SPEC.- PASS? Soil Description
SIZE FINER PERCENT (X-NO) Poorly graded gravel with silt and sand
WT
1.5 in. 100.0
I in. 97.7 Dated 4-13-2006
.75 in. 94.7
.625 in. 92.0 Atterberg Limits
.5 in. 84.7 PL= LL= Pl=
.375 in. 74.0
#4 51.2
#8 31.1 Coefficients
#10 27.8 D85= 12.8 D6()= 6.27 D50= 4.57
#20 18.3 D30= 2.24 D15= 0.498 D10= 0.146
#40 14.2 CU= 43.02 Cc= 5.49
#90 10.8
#100 10.1 Classification
#200 8.3 USCS= GP-GM AASHTO= A-l-a
Remarks
As Received Moisture Content=8.5%
F.M.=2.39
(no specification provided)
Sample No.: 6298 Date., 4-18-2006
Location: Elev./Depth: @ 23'
Client: Mabor-Pita
K:1 Project: 2006 General Laboratory Work
CASCADE 7ESMNO L-ABORA-rORY, 1"C.
TESTINO&INSPECTION/E"4�NEEPIS Project No)�:_,-960J;0�21-2
L112010 N.E. -�TI-I PLACE Ki- NO,W ON W90�3. saa-9000 Technician: Nick Averill Inspector:
FCC
Particle Size Distribution Report
100
90
80-
70--
LLJ 60 -
U-
IV
40
fl
30--
2010
-
14�
0
500 100 10 1 01 0.51 0.001
GRAIN SIZE- mm
%COBBLES %GRAVEL %SAND %FINES
CRS. FINE CRS. MEDIUM FINE SILT CLAY
0.0 26.9 30.1 11.0 14.2 11.9 5.9
SIEVE PERCENT SPEC.* PASS? Soil Description
SIZE FINER PERCENT (X=NO) Well-graded gravel with silt and sand
1.5 in. 100.0 MP-X
I in. 87.2 Dated 4-13-2006
.75:in. 73.1
.625 in. 70.3 AtterbeTq Limits
.5 in. 60.3 PL= LL= Pl=
.375 in. 55.1
#4 43.0
#8 33.9 Coefficients
#10 32.0 D85= 24.4 D60= 12.6 D50= 6.84
#20 24.2 D30= 1.65 D15= 0-311 D1 0= 0.178
#40 17.8 CU= 70.78 Cc= 121
#80 10.1
#100 8.5 Classification
9200 5.9 USCS= GW-GM AASHTO= A-l-a
Remarks
As Received Moisture Content=7.2%
F.M.=2.86
(no specification provided') --
Sample No.: 6299 Date: 4-18-2006
Location: ElevJDepth: Above
Client: Milbor-Pita
Project: 2006 General Laboratory Work
CASCAOE TESTING L,6,SCZ)RA70RY, INC.
Project No:
601 2
(P-0EN 8---�Deoc) Technician: Nick-Averill Inspector:
/3
le(g�
/T. a7
Lilliwaup Falls Power Project Geotechnical Report: Winter Creek Channel Relocation
Appendix C
Mason County Geotechnical Report Checklist
Jacobs Associates Rev. No. 0/December 2012
Lilliwaup Falls Power Project Geotechnical Report: Winter Creek Channel Relocation
Mason County Department of Community Development
Submittal Checklist For a Geotechnical Report
Instructions:
This checklist must be submitted with a Geotechinical Report and completed, signed, and
stamped by the licensed professional(s) who prepared the Geotechnical Report for review by
Mason County pursuant to the Mason County Resource Ordinance. If an item found to be not
applicable, the report should explain the basis for the conclusion.
Applicant/Owner: Lilliwaup Falls Hydroelectric Power Project
Parcel #32319-23-00000,32319-24-00000,32319-24-00030
Site Address: Lilliwaup Falls Area on the Reed Property
(1) (a) A discussion of general geologic conditions in the vicinity of the proposed development,
Located on page(s) Page 3
(b) A discussion of specific soil types,
Located on page(s) Pages 5& 6
(c) A discussion of ground water conditions,
Located on page(s) Page 6
(d) A discussion of the upslope geomorphology,
Located on page(s) Page 3
(e) A discussion of the location of upland waterbodies and wetlands,
Located on page(s) Page 3. Other than Lilliwaup &Winter Creek, there are no wetlands or
waterbodies in project area
(f) A discussion of history of landslide activity in the vicinity, as available in the referenced
maps and records.
Located on page(s) Page 3 Section 2.3
(2) A site plan which identifies the important development and geologic features.
Located on Map(s) Figures 2, 3 & Appendix A
(3) Locations and logs of exploratory holes or probes.
Located on Map(s) Figure 3 Plan & Logs in Appendix B
(4) The area of the proposed development, the boundaries of the hazard, and associated
buffers and setbacks shall be delineated (top, both sides, and toe) on a geologic map of
the site.
Located on Map(s) Drawings in Appendix A show plan and sections.
(5) A minimum of one cross section at a scale which adequately depicts the subsurface
profile, and which incorporates the details of proposed grade changes.
Jacobs Associates Rev. No. 0/December 2012
P� 17
Lilliwaup Falls Power Project Geotechnical Report: Winter Creek Channel Relocation
Located on Map(s) Appendix A's drawings
(6) A description and results of slope stability analyses performed for both static and seismic loading
conditions.Analysis should examine worst case failures. The analysis should include the Simplified
Bishop's Method of Circles. The minimum static safety factor is 1.5, the minimum seismic safety
factor is 1.1, and the quasi-static analysis coeffients should be a value of 0.15.
Located on page(s) page 7, but really not applicable
(7) (a) Appropriate restrictions on placement of drainage features,
Located on page(s Groundwater Seepage not an issue with this project
(b) Appropriate restrictions on placement of septic drain fields,
Located on page(s) none in project
(c) Appropriate restrictions on placement of compacted fills and footings,
Located on page(s) page 7
(d) Recommended buffers from the landslide hazard areas shoreline bluffs and the tops of
other slopes.
Located on page(s) Not applicable
(e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops
of other slopes.
Located on page(s) Not applicable on this project
(8) Recommendations for the preparation of a detailed clearing and grading plan which
specifically identifies vegetation to be removed, a schedule for vegetation removal and
replanting, and the method of vegetation removal.
Located on page(s) to relocate stream, no clearing is required &the fill will become
parking area. Plans include Restoration Plan.
(9) Recommendations for the preparation of a detailed temporary erosion control plan which
identifies the specific mitigating measures to be implemented during construction to
protect the slope from erosion, landslides and harmful construction methods.
Located on page(s) Plans include Stormwater Pollution Prevention Plan & Details.
(10) An analysis of both on-site and off-site impacts of the proposed development.
Located on page(s) not covered in the qeotechnical report but other submittals
(11) Specifications of final development conditions such as, vegetative management, drainage,
erosion control, and buffer widths.
Located on page(s) Drawings are being prepared w/WSDOT std specification as reference
(12) Recommendations for the preparation of structural mitigation or details of other proposed
mitigation.
Located on page(s) not applicable
(13) A site map drawn to scale showing the property boundaries, scale, north arrow, and the
location and nature of existing and proposed development on the site.
Jacobs Associates Rev. No. 0/December 2012
�. 30
Lilliwaup Falls Power Project Geotechnical Report: Winter Creek Channel Relocation
Located on Map(s) Figure 1 & Figure 3, and
Appendix A; all the work is within the Reed Property.
I, Frank W. Pita, hereby certify under penalty of perjury that I am a civil engineer licensed in the
State of Washington with specialized knowledge of geotechnical/geological engineering or a
geologist or engineering geologist licensed in the State of Washington with special knowledge of
the local conditions. I also certify that the Geotechnical Report, dated December 2012 and
entitled Lilliwaup Falls Power Project/Winter Creek Channel Relocation at Lilliwaup Falls
meets all the requirements of the Mason County Resource Ordinance, Landslide Hazard
Section, is complete and true, that the assessment demonstrates conclusively that the risks
posed by the landslide hazard can be mitigated through the included geotechnical design
recommendations, and that all hazards are mitigated in such a manner as to prevent harm to
property and public health and safety.
(Signature and Stamp)
p 17522
S1ONAL
Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical
Report.
Jacobs Associates Rev. No. 0/December 2012
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