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CORTIANA CULVERTS REPLACEMENT PROJECT
STRUCTURE NO. 08520
HYDROTECHNICAL DESIGN BRIEF
MOTI PROJECT 24798
Prepared for:
BC Ministry of Transportation and Infrastructure Southern Interior Region
Kamloops, BC
Prepared by:
Northwest Hydraulic Consultants Ltd. Kamloops, BC
20 December, 2019
NHC Ref No. 3004231‐01
Cortiana Culverts Replacement Project ii Hydrotechnical Design Brief
TABLE OF CONTENTS
DISCLAIMER .................................................................................................................................................... I
LIST OF TABLES .............................................................................................................................................. II
LIST OF APPENDICES ...................................................................................................................................... II
1 INTRODUCTION...................................................................................................................................... 1 1.1 Design codes and references ........................................................................................................... 1 1.2 Information provided by MoTI ......................................................................................................... 2 1.3 Information from other sources ...................................................................................................... 2
2 INONOAKLIN CREEK DESCRIPTION ........................................................................................................ 3 2.1 Watershed and crossing reach physical characteristics .................................................................. 3 2.2 Streamflow estimates ...................................................................................................................... 3
3 HYDRAULIC ANALYSIS OF PROPOSED WATERWAY ............................................................................... 3 3.1 Hydraulic summary .......................................................................................................................... 4 3.2 Design flood level and required bridge clearance ........................................................................... 4 3.3 Aggradation, degradation and scour ............................................................................................... 5 3.3.1 Aggradation................................................................................................................................. 5 3.3.2 Degradation ................................................................................................................................ 5 3.3.3 Scour ........................................................................................................................................... 5
3.4 Rock riffle grade control................................................................................................................... 5 3.5 Riprap protection for streambanks .................................................................................................. 6
4 REFERENCES ........................................................................................................................................... 7
LIST OF TABLES
Table 1. Summary of the hydraulic model results for the new channel and bridge ..................................... 4
LIST OF APPENDICES
APPENDIX A Set of one (1) Drawing –Waterway Opening and Channel Improvement Design
Cortiana Culverts Replacement Project 1 Hydrotechnical Design Brief
1 INTRODUCTION
The Cortiana Culverts Structure No. 08520 (Cortiana Culverts) convey Inonoaklin Creek across Highway 6
approximately 102 km east of Vernon, BC and about 33 km west of the Arrow Lakes Ferry at
Needles, BC. The BC Ministry of Transportation and Infrastructure (MoTI) is concerned that the existing
structure is undersized to convey the design stream flow, for which the current standard is the 200‐year
peak instantaneous flow. There is also concern that some or all the culverts may not have been
constructed properly. Scour of the creek bed and erosion of the banks at the outlet have been an
ongoing concern, and from time to time there has been settlement of the road prism, indicating that
piping has likely occurred. In general, these problems have been intensifying over the past decade.
Northwest Hydraulic Consultants Ltd. (NHC) was retained by MoTI (under Contract No. 831CS0995) to
carry out a hydrotechnical assessment and the hydrotechnical design of a replacement for the Cortiana
Culverts. Given the findings presented in Cortiana Culverts Replacement Project 24798 – Hydrotechnical
Assessment and Preliminary Design Report (NHC 2019), a clear span rectangular bridge opening was
selected as the preferred replacement option. This report provides the detailed hydraulic design of the
bridge and approach channel.
1.1 Design codes and references
The following design codes and reference documents form the basis of the hydrotechnical study and
establishment of design constraints:
Design Codes:
CAN/CSA‐S6‐14 in conjunction with the BC MoTI Supplement to CHBDC S6‐14 (2016)
BC MoTI Supplement to TAC Geometric Design Guide (2019)
BC Ministry of Transportation and Infrastructure Standards and Guidelines:
BC MoTI Standard Specifications for Highway Construction (2016)
BC MoTI Resilient Infrastructure Engineering Design – Adaptation to the Impacts of Climate
Change and Weather Extremes (2019)
Other Applicable Federal and Provincial Guidelines:
BC Ministry of Forests, Lands and Natural Resource Operations, and Fisheries and Oceans
Canada, Fish‐stream Crossing Guidebook (2012).
Hydrotechnical Design Guidelines:
TAC Guide to Bridge Hydraulics (2001)
Cortiana Culverts Replacement Project 2 Hydrotechnical Design Brief
Hydraulic Design of Stable Flood Control Channels (NHC, 1984)
Professional Practice Guidelines – Legislated Flood Assessments in a Changing Climate in BC
(V2.1) (EGBC, 2018)
1.2 Information provided by MoTI
The following reference drawings, reports and survey data were provided by MoTI:
photos of the crossing taken during the 2018 flood event.
1.3 Information from other sources
The following reference drawings, reports and survey data were obtained from other sources:
Ground surveys and base plan (WSP Canada Inc. 2018)
Cortiana Culverts Replacement Project 3 Hydrotechnical Design Brief
2 INONOAKLIN CREEK DESCRIPTION
2.1 Watershed and crossing reach physical characteristics
The crossing reach, where the subject crossing exists, is considered to extend about 125 m upstream of
the Cortiana Culverts to the confluence of Inonoaklin Creek with Banting Creek, and 30 m downstream
to a bedrock fall. The following information summarizes baseline physical characteristics of the
Inonoaklin Creek watershed and the crossing reach.
Watershed area to the crossing: 107.3 km2
Maximum watershed elevation: 1996 m
Median watershed elevation: 1569 m
Elevation at crossing: 1135 m
Channel morphology at crossing: Non‐alluvial bedrock and/or riprap‐protected
channel, tightly confined by road and building infrastructure
Channel slope: 2.0 percent (0.02 m/m)
Existing Channel bottom width: 3.5 – 4.5 m
Bed material D50 250 mm
2.2 Streamflow estimates
Peak Flood flow estimates for Inonoaklin Creek are based on a set of flood curves developed by NHC.
For background on the development of the curves please refer to Cortiana Culverts Replacement Project
24798 – Hydrotechnical Assessment and Preliminary Design Report (NHC 2019). The following flow
estimates were used in the design of the permanent crossing, with the future 200‐year peak
instantaneous flow estimate being the basis for sizing the clear span bridge.
Mean annual flow: 1.38 m3/s
2‐year annual peak flow: 15.3 m3/s
10‐year annual peak flow: 25.3 m3/s
100‐year annual peak flow: 37.9 m3/s
200‐year annual peak flow: 41.8 m3/s
200‐year design flow*: 46.0 m3/s
*Includes a 10 percent increase to account for the effects of climate change.
3 HYDRAULIC ANALYSIS OF PROPOSED WATERWAY
The preferred option for replacement of Structure No. 08520 is a clear span, rectangular bridge, with
vertical abutment walls. The new waterway design consists of a trapezoidal channel with a bottom
width of 4.5 m and 1.5H:1V side slopes.
Cortiana Culverts Replacement Project 4 Hydrotechnical Design Brief
Channel improvements (regrading, widening and armouring) are required for approximately 80 m
upstream and 35 m downstream of Highway No. 6. Refer to the drawing in Appendix A for details.
The waterway design includes lowering the creek invert from the outlet of the existing culverts to about
40 m upstream of the crossing. The recommended lowering is expected to extend to/be close to the
underlying bedrock surface, resulting in a 3.5 percent grade through the crossing and about 0.8 m of
additional vertical clearance for the replacement structure. The grade control for the newly steepened
channel section will be provided by a rock riffle grade control composed of 500‐kg, void‐filled riprap at a
10 percent slope to tie into the upstream channel. Additional 500‐kg void‐filled riprap is recommended
for 11.5 m along the 3.5 percent channel to tie the downstream bedrock channel into the grade control.
From approximately 80 m to 35 m upstream of the crossing, 500‐kg riprap with a nominal thickness of
1.2 m is recommended along the left bank of the approach channel, adjacent to the highway. The
remaining left bank and concrete retaining wall leading up to the bridge is protected with 1000‐kg
riprap, sloped at 1.5H:1V. The same riprap specification is used for both left and right banks downstream
of the bridge opening. The right bank directly upstream of the bridge opening is located along an outer
bend, where channel velocities are expected to peak. Therefore, 1000‐kg riprap sloped at 2H:1V is
recommended with a nominal thickness of 1.8 m to tie into the bridge and the existing upstream
bedrock.
3.1 Hydraulic summary
The following table summarizes the hydraulic performance of the proposed permanent crossing (see
NHC, 2019 for a more in‐depth discussion of the hydraulic analysis of existing crossing).
Table 1. Summary of the hydraulic model results for the new channel and bridge
Peak Flow
Return Period Peak Flow (m3/s) Flood
Level1, (El., m)
Average
Velocity2
(m/s)
2‐year 15.3 1135.8 2.4
10‐year 25.3 1136.2 2.7
100‐Year 37.9 1136.7 3.0
200‐Year 41.8 1136.8 3.1
200‐Year Design Flow3 46.0 1136.9 3.2
Notes: 1. The flood levels shown are at the downstream side of the proposed new bridge. 2. Average velocities are maximum average values within the hydraulic opening. 3. Includes a 10 percent increase to account for the effects of climate change.
3.2 Design flood level and required bridge clearance
MOTI standard for flood clearance is 1.5 m above the 200‐year design flood level, El. 1136.9 m.
Therefore, the minimum bridge soffit elevation required for flood clearance at both bridges shall be El.
Cortiana Culverts Replacement Project 5 Hydrotechnical Design Brief
1138.4 m. It should be noted that the recommended clearance is measured at the downstream face of
bridge due to the flat flood profile through the crossing and the super elevation of the bridge.
3.3 Aggradation, degradation and scour
3.3.1 Aggradation
NHC expects cycles of aggradation to continue in the upper portion of the bridge reach (between the
bedrock outcrop and Banting Creek confluence) as it has in the past. Sediment transport capacity will be
significantly higher through the lower portion of the reach with a new bridge replacing the existing
culverts. The plunge pool downstream of the bedrock falls is expected to partially infill with coarse
sediment and wood debris over time, which may reduce the aesthetics of the area for local landowners.
3.3.2 Degradation
Degradation and head cut erosion may be prone to occur in the upper portion of the reach due to
elimination of the backwater effect that exists with the Cortiana culverts. To counteract this, NHC has
designed the 500‐kg, void‐fill riprap grade control. The degradation potential through the bridge and
downstream of it is nil since the new channel will be at or near the bedrock surface.
3.3.3 Scour
Natural scour occurs in streams even if the channel is not constricted or controlled to a significant
degree. The causes of natural scour can include: i) an unusually large flood; ii) accelerated, deep flow
along the outside of a bend; iii) lateral shifting of the channel thalweg; iv) flow alongside or impinging
upon rock outcrops, debris jams, other hard points or rigid materials along the channel boundaries; and
iv) sudden concentrations of flow such as the confluence of two or more channels.
At the Cortiana site, the new invert of the creek through the bridge will be at or near the bedrock
surface, which will minimize or eliminate scour potential. However, the left bank of the approach
channel (currently protected with 100‐kg riprap) may still be susceptible to natural scour. At this
location, the 200‐year natural scour elevation has been estimated using the Modified Blench procedure
(TAC 2004). The resulting natural scoured depth is 2.2 m below the 200‐year design flood level, or to El.
1,136.3 m, suggesting there is moderate natural scour potential at this location.
Although the remaining riprap protection is expected to be placed on bedrock within the channel, the
exact extent of bedrock within the channel is unknown. Therefore all riprap has been designed to
protect against natural scour, in the event there is no bedrock encountered in the channel.
3.4 Rock riffle grade control
The rock riffle grade control shall be constructed using void‐filled, Class 500‐kg riprap, which is a
composite, placed mixture of riprap pieces and streambed material. The grade control has been
designed to tie the new bridge channel into the existing upstream channel. The void‐filled riprap shall
Cortiana Culverts Replacement Project 6 Hydrotechnical Design Brief
be constructed along the full width of the channel bed at a thickness of 1.2 m. The protection should be
constructed in layers, with a layer of streambed material added (and possibly washed in) to the riprap to
seal voids.
3.5 Riprap protection for streambanks
For rectangular bridge openings, and for approach and exit channels to the bridge, riprap armouring
protection is required to prevent the loss of embankment and approach fill material and to protect the
bridge abutments. The size for graded riprap has been determined using the U.S Army Corps of
Engineers method (USACE, 1991; TAC, 2004). The hydraulic conditions vary through the proposed
channel design and therefore the riprap specifications vary depending on the location of the proposed
riprap protection.
500‐kg riprap sloped at 1.5:H:1V is suitable for the protection of the left bank approach channel,
upstream of the bridge, extending from river station 0+010 to 0+050. 1000‐kg riprap is recommended
along the remainder of the approach channel. The left bank riprap is suitable to remain sloped at
1.5H:1V, whereas the right bank riprap, location along the outside of the bend, is designed as 2.0H:1V
and 1.8 m nominal thickness to account for the increase in velocity along the right bank. Downstream of
the bridge opening, 1000‐kg riprap sloped at 1.5H:1V is designed along both right and left banks.
The toe of all riprap shall be keyed into the channel bed to protect against scour. If bedrock is present,
the riprap shall be secured to the bedrock with rock anchors to prevent sliding.
Cortiana Culverts Replacement Project 7 Hydrotechnical Design Brief
4 REFERENCES
Arcement, G.J. and Schneider, V.R. (1984). Guide for Selecting Manning’s Roughness Coefficients for
Natural Channels and Flood Plains. U.S. Geological Survey, Water Supply Paper 2339. Washington, D.C.
CSA International. (2000). National Standard of Canada, Canadian highway Bridge Design Code,
CAN/CSA‐S6‐00
EGBC. 2019. “Legislated Flood Assessments in a Changing Climate in BC, Version 2.1.”
https://www.egbc.ca/getmedia/4264e239‐5720‐40c7‐80fa‐cf0f03eda400/V2‐0‐Leg‐Flood‐Assessments‐
in‐BC‐FINAL_2018‐07‐16‐Web.pdf.aspx.
Mastin, M.C., Konrad, C.P., Veilleux, A.G., and Tecca, A.E., 2016. Magnitude, frequency, and trends of
floods at gauged and ungauged sites in Washington (ver 1.2, November 2017): U.S. Geological Survey
Scientific Investigations Report 2016–5118, 70 p.
Ministry of Forests Lands and Natural Resource Operations (MFLNRO). (2012). Fish‐stream Crossing
Guidebook, Revised Edition.
Ministry of Transportation and Infrastructure (MoTI). (2007). BC Supplement to TAC Geometric Design
Guide, 2007 Edition.
Northwest Hydraulic Consultants Ltd. (NHC)., 2019 Cortiana Culverts Replacement Project 24798,
Hydrotechnical Assessment and Preliminary Design Report R1
Northwest Hydraulic Consultants (NHC). (1984). Hydraulic Design of Stable Flood Control Channels. II‐
Draft Guidelines for Preliminary Design. Prepared for U.S Army Corps of Engineers Seattle District.
Obedkoff, W. (2001). Streamflow in the Kootenay Region, June 2001, Water Inventory Section, Resources
Inventory Branch, Ministry of Environment Lands and Parks, Province of British Columbia.
Schmocker, L. and Hager, W.H. (2010). Drift accumulation at river bridges. River Flow 2010.
Transport Association of Canada (TAC). (2001). Guide to Bridge Hydraulics (2nd Edition). Thomas Telford,
London.
U.S Army Corps of Engineers. (1991). Hydraulic Design of Flood Control Channels. Engineering and
Design Manual EM‐1110‐2‐1601, Washington, D.C.
USACE (1994). Channel Stability Assessment for Flood Control Projects. EM 1110‐2‐1418. 31 October
1994.
USACE. (2015). HEC‐RAS River Analysis System (Version 5.03). Hydrologic Engineering Center, Davis CA
APPENDIX A
Design Drawing Detailed Waterway Opening and Channel Improvements
1130
1135
1140
1145
1130
1135
1140
1145
0+10 0+20 0+30 0+40 0+50 0+60 0+70 0+80 0+90 1+00 1+10 1+20 1+30
Q200 (DESIGN)
10%3.5%
1.200
PROFILE ALONG CREEK CENTRELINE - INONOAKLIN CREEKSCALE = 1:250
1.500
WP7
WP103.5%
13.000 11.500
EXISTING CREEK BED
DESIGN CHANNEL
GRADE CONTROL500-KG VOID-FILLED RIPRAP
EXISTING CULVERTS AND FILL TO BE REMOVED
DESIGN TOP OF RIPRAP
1000-KG BANK RIPRAP500-KG BANK RIPRAPPROPOSED BRIDGE
101+00101+50
P
I
D
0
1
6
-
4
9
5
-
5
1
9
D
L
1
4
0
2
9
D
L
1
6
3
2
9
0+000
0+010 0+020 0+030 0+040 0+050 0+060 0+070
0+080
0+09
0
0+10
0
0+1100+120
0+13
00+
133
WP1
WP2
WP3
WP4
WP5
WP6
WP8
WP9 WP10
WP11
WP12
WP13
WP14
WP15
WP17
WP18WP19
WP20 WP21 WP22WP23
WP24
WP25
WP26
WP27
WP28
WP29
WP30
WP7
WP16
1000-KGRIPRAPGRADE CONTROL
500-KG VOID-FILLED RIPRAP
PLACE RIPRAP AGAINST WALL AS REQUIREDPLACE RIPRAP AGAINSTWALL AS REQUIRED
TRIM BACK OF RIPRAP TO MINIMIZEENCROACHMENT INTO PROPERTY
BLEND RIPRAP TOEXISTING BEDROCK
BLEND RIPRAP INTO EXISTINGBEDROCK OUTCROP
500-KG RIPRAP
1000-KGRIPRAP
BRIDGE AND RETAINING WALL(SEE NOTE 4)
FIELD FIT TRIBUTARY TIE-IN(EG. USE VOID-FILLED RIPRAP TO CREATESEMI-IMPERVIOUS CHANNEL BOTTOM)
FIELD-FITSMOOTHTIE-IN WITHEXISTINGVEGETATEDBANK
WRAP RIPRAP AROUND WALL
1.51
1.51
1.200
1.500
1.500
1.800
1.51
21
1.51 1.5
11.500
1.500
SECTION 1
SECTION 2
SECTION 3
SECTION 4
Q200
Q200
Q200
Q200
SEE NOTE 14
SEE NOTE 14
SEE NOTE 14
WP17
WP16
WP24WP26
WP25
SCALE = 1:100
SCALE = 1:100
SCALE = 1:100
SCALE = 1:100
WP23
WP13
4.500
1.200
0.600
0.300
0.300
0.300
1.200
1.200
1.500
1.500
0.600
1.500
1.500 1.500
1.500
0.6000.600
4.500
VARIES
11
0.700
1.000
0.5000.500
11
11
WP14
1000-KG RIPRAP(SEE NOTES 6 TO 10)
1000-KG RIPRAP(SEE NOTES 6 TO 10)
500-KG RIPRAP(SEE NOTES 6 TO 10)
500-KG VOID-FILLED RIPRAP
1000-KG RIPRAP(SEE NOTES 6 TO 10)
1000-KG RIPRAP(SEE NOTES 6 TO 10)
EXISTING BUILDING EDGE
TRIM BACK OF RIPRAPTO SIT FLUSH WITH WALL
TRIM BACK OF RIPRAPTO SIT FLUSH WITH WALL
TRIM BACK OF RIPRAPTO SIT FLUSH WITH WALL
SEE NOTE 4
CAP THE 500-KG RIPRAP WITH 10-KG RIPRAP, WRAP IN GEOTEXTILE,AND REINSTATE SHOULDER OVERTOP (SEE DETAIL 1)
CAP THE 1000-KG RIPRAP WITH 10-KG RIPRAP, WRAP INGEOTEXTILE, AND REINSTATE BANK MATERIAL OVERTOP(SEE DETAIL 1)
EXISTING EDGE OF PAVEMENT
CAP THE 1000-KG RIPRAP WITH10-KG RIPRAP AND REINSTATEPAVEMENT OVERTOP AS REQUIRED(SEE DETAIL 1)
SEE NOTE 4
1000-KG RIPRAP(SEE NOTES 6 TO 10)
TRIM RIPRAP AS REQUIREDTO AVOID ENCROACHMENTINTO EXISTING PROPERTY
TIE INTOEXISTINGBEDROCK
SEE NOTE 4
GEOTEXTILE COVEREDWITH 150mm COMMON FILL
GEOTEXTILE COVEREDWITH 150mm COMMON FILL
GEOTEXTILE COVEREDWITH 150mm COMMON FILL(BOTH SIDES)
GEOTEXTILE COVEREDWITH 150mm COMMON FILL(BOTH SIDES)
500-KG VOID-FILLED RIPRAP
500-KG VOID-FILLED RIPRAP
WORKPOINTS
WP
WP1
WP2
WP3
WP4
WP5
WP6
EASTING
403529.80
403525.70
403537.64
403533.19
403541.16
403536.69
NORTHING
542140.21
542137.29
542123.80
542121.59
542115.69
542113.48
ELEVATION
1139.97
1136.61
1139.62
1136.30
1139.47
1136.14
WORKPOINTS
WP
WP7
WP8
WP9
WP10
WP11
WP12
EASTING
403538.86
403548.26
403543.90
403550.29
403543.77
403546.10
NORTHING
542105.48
542099.34
542097.01
542083.76
542068.22
542081.14
ELEVATION
1137.21
1138.53
1134.87
1135.65
1138.18
1133.84
WORKPOINTS
WP
WP13
WP14
WP15
WP16
WP17
WP18
EASTING
403554.55
403550.38
403560.89
403552.89
403556.76
403570.62
NORTHING
542087.74
542085.51
542076.09
542061.30
542069.30
542058.22
ELEVATION
1137.66
1134.50
1133.65
1138.12
1133.68
1137.79
WORKPOINTS
WP
WP19
WP20
WP21
WP22
WP23
WP24
EASTING
403565.26
403570.94
403574.25
403578.70
403585.26
403588.03
NORTHING
542068.07
542082.00
542075.93
542067.72
542057.03
542059.03
ELEVATION
1133.14
1136.31
1133.28
1132.94
1134.74
1132.46
WORKPOINTS
WP
WP25
WP26
WP27
WP28
WP29
WP30
EASTING
403596.63
403592.41
403596.44
403597.68
403600.07
403596.16
NORTHING
542065.24
542062.20
542043.80
542049.44
542059.83
542057.01
ELEVATION
1135.93
1132.46
1135.95
1132.62
1135.45
1132.79
AA
A
A
A
DETAIL 2 - RIPRAP ANCHORING TO BEDROCKSCALE = N.T.S.
A
GROUND ANCHOR POINTUSE DYWIDAG THREADBAR 25 DIAMETER ASTM A615GRADE 517MPa WITH EYE NUTS FLUSH MOUNTED TOROCK, OR EQUIVALENT(SEE NOTE 12 FOR ANCHORAGE)
MIN. 1000mm BOULDER, DRILLED
58" 6 x 19 FIBRE CORE WIRE ROPE (OR CHAIN)
CONFORMING TO CSA G4. CABLES SHALL BE UNSPLICED.
EXISTING BEDROCKSECTIONS OF ANCHOREDRIPRAP MUST BEGIN ANDFINISH WITH ANCHORS
INSTALL WIREROPE CLIPS ONBOTH SIDES OFANCHORS
SEE NOTE 10 TO 12
MAXIMUM THREE BOULDERSBETWEEN ANCHORS
RIPRAP ANCHORLOCATIONS TO BEFIELD-FIT
1135
1140
1145
1135
1140
1145
101+30 101+40 101+50 101+60 101+70
PROFILE ALONG L100 - HIGHWAY No. 6SCALE = 1:250
Q200 EL. 1136.9(DOWNSTREAM)
PROPOSED CHANNEL BEDEL. 1134.8
1.51
1.200
DETAIL 1 - GEOTEXTILE WRAP AND TOE ANCHORING
Q200
SCALE = N.T.S.
0.3000.300
A
0.150RIPRAP(SEE NOTES 6 TO 10)
GEOTEXTILE BEHIND SLOPING RIPRAPTO WRAP OVER 10-KG RIPRAP AND BECOVERED WITH COMMON FILL
ANCHORED BOULDERINSTALLED FIRST ONBEDROCK PRIOR TOCONSTRUCTION OFRIPRAP
GEOTEXTILE COVEREDWITH 150mm COMMON FILL
Southern Interior Region
Ministry of TransportationBRITISHCOLUMBIA & Infrastructure
NOTES:1. REFER TO NOTES 2 TO 5 ON DWG R2-1101-101 FOR NOTES ON SURVEY DATUM.2. UTILITY DATA SHOWN ARE FROM FIELD EVIDENCE AND BC ONE CALL INFORMATION. UTILITIES OTHER THAN
THOSE SHOWN MAY EXIST.3. ALL LEGAL BOUNDARIES ARE APPROXIMATE AND WERE LOCATED USING ICIS CADASTRAL MAPPING, HYDRO POLE
AND ROADWAY CL TIES.4. REFER TO DRAWINGS 8520-12 (GENERAL ARRANGEMENT) AND 8520-13, 14, 15, 16, 17 AND 18 (RETAINING WALLS).5. REFER TO PROBE HOLE TABLE ON DRAWING 8520-25 FOR DEPTH TO INFERRED BEDROCK.6. RIPRAP SPECIFICATIONS AND INSTALLATION SHALL CONFORM TO THE MOTI STANDARD SPECIFICATION FOR
HIGHWAY CONSTRUCTION SS 205.7. ALL SLOPING RIPRAP SHALL BE UNDERLAIN WITH CLASS 1, NON-WOVEN GEOTEXTILE.8. RIPRAP APRON MAY BE FIELD-FIT OR OMITTED IN LOCATIONS WHERE BEDROCK IS ENCOUNTERED.9. WHERE TOE OF RIPRAP IS IN CONTACT WITH BEDROCK, THE RIPRAP TOE BOULDERS SHALL BE ANCHORED INTO
THE BEDROCK (SEE DETAIL 2).10. ROCK ANCHORS SPECIFICATIONS AND INSTALLATION SHALL CONFORM TO THE MOTI STANDARD SPECIFICATION.
ANCHOR LOCATIONS TO BE CONFIRMED AND APPROVED IN THE FIELD.11. ROCK ANCHORS TO BE HOT DIP GALVANIZED IN CONFORMANCE TO ASTM A123 OR A153.12. ROCK ANCHORS TO BE DRILLED AND FIXED INTO ROCK w/GROUT. MIN. 1000mm EMBEDDED WITH TWO
CENTRALIZERS AT TOP AND BOTTOM OF BAR INTO A 75mm Ø x 1200mm HOLE AND INSTALLED IN ACCORDANCEWITH SPECIAL PROVISIONS.
13. CHANNEL ALIGNMENT PROVIDED BY ALLNORTH.14. FINISHED HIGHWAY DESIGN SURFACE BY ALLNORTH NOT SHOWN.
PLAN VIEWSCALE = 1:250
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