Mora Rd_Engineering Calculations.pdf

Boulder Sizing

Project Number

Scale

Designed By Date Checked By Date Sheet No:

Define Input Parameters

Average Boundary Shear = psf Max structure value for proposed conditions Boulder Size (D50) = ft

Calculate Minimum Boulder Size Using HRB Method

Based on the figure above, a linear relationship is observed between boulder diameter and the boundary shear stress required to move the material. The below relationship is recommended by HRB for stable material:

Using this relationship for boundary shear, the minimum boulder size for stability is equal to ft

Conclusion

3/3/2025 1 of 2

Objective: Determine Boulder Size for Fish Passage Boulders on Revetment Structures

PROJECT Repair Storm Damage at Mora Road 95% Design 194-1343-0002

SUBJECT Boulder Stability Calculations NA

JV 2/14/2025 AD

Safety Factor = /3 0.9 =5 3.16 OK

Using the HRB method, the selected boulder size is sufficient for the average boundary shear anticipated in the stream simulation channel segment for the 100-yr peak flow with resiliency and the record low tide.

References:

HRB (Highway Research Board). 1970. Tentative Design Procedure for Riprap-Lined Channels. National Academy of Sciences, National Cooperative Highway Research Program, Report 108.

USBR (United States Department of the Interior Bureau of Reclamation, 2007. Rock Ramp Design Guidelines.

https://www.usbr.gov/tsc/techreferences/mands/mands-pdfs/RockRampDesignGuidelines_09-2007_508.pdf

3.8

0.95 g

Project Number

Scale

Designed By Date Checked By Date Sheet No:

Define Input Parameters

Ds = boulder Size (D50) = ft Rock size, 3-ft diameter o = longitudinal bed slope = ft/ft Based on channel design 1 = bank side slope ft/ft Based on channel design deg Based on USBR guideline

0 = bed shear stress = psf Max structure value for proposed conditions

Calculate Safety Factor of Proposed Boulder Size Using USBR Method

Use Equation 7-1 from USBR:

0 = 1 = SF = OK

Conclusion

Using the USBR Method, the selected boulder size provides a sufficient Safety Factor for stability in the stream simulation channel segment for the 100-yr peak flow with resiliency and the record low tide.

Objective: Determine Boulder Size for Fish Passage Boulders on Revetment Structures

PROJECT Repair Storm Damage at Mora Road 95% Design 194-1343-0002

SUBJECT Boulder Stability Calculations NA

JV 2/14/2025 AD

0.3

3/3/2025 2 of 2

References:

HRB (Highway Research Board). 1970. Tentative Design Procedure for Riprap-Lined Channels. National Academy of Sciences, National Cooperative Highway Research Program, Report 108.

USBR (United States Department of the Interior Bureau of Reclamation, 2007. Rock Ramp Design Guidelines.

https://www.usbr.gov/tsc/techreferences/mands/mands-pdfs/RockRampDesignGuidelines_09-2007_508.pdf

0.01

3.8

0.2584 21.959 0.179 2.02 deviation from horizontal = 0 deg Based on USBR guideline

Riprap Sizing

Calculated by: JV Checked by: AD Sheet No: 1 of 2

Estimate D30

Equation: D30 = SfCsCvCt w s w))1/2 V/(K1gd)1/2}2.5 where: D30 = material size in which 30 percent is finer by weight [ft]

Define Input Parameters

Safety Factor Sf = 1.50 Minimum of 1.1, usually 1.1-1.5

Stability Coefficient for Incipient Failure Cs = 0.300 Typical for angular rock

Vertical velocity distribution coefficient Cv = 1.21 Conservative assumption of Cv=1.283-0.2*log(R/W) Centerline bend radius R = 840.00 ft Value used for bend scour analysis

Water surface width W = 350.00 ft Value used for bend scour analysis Ratio R/W = 2.4

Thickness coefficient Ct = 1.00 Assume 1 for 1*D100 or 1.5*D50

Flow depth d = 23.96 ft Average for proposed structure Specific weight of water w = 62.40 lb/ft3

Specific weight of stone s = 165.00 lb/ft3

Local velocity V = 5.85 ft/s Average for proposed structure Gravitational constant g = 32.20 ft/s2

Side slope correction factor K1 = 0.58 Use K1 curve recommended for design Side slope angle 39.0 deg Measured from terrain Angle of repose 40.0 deg Typically 40 degrees

Side slope velocity Vss = 9.02 ft/s Vss = V * {1.74 - 0.52*Log(R/W)}

Calculation Results:

D30 = 0.83 ft D30 = 9.95 Inches

USBR (U.S. Bureau of Reclamation). 2007. Stone Sizing Criteria. Technical Supplement 14C, National Engineering Handbook.

Project: Repair Storm Damage at Mora Road (95% Design)

Subject: Material Sizing Calculations - Embankment

Project No:

Date:

194-1343-0002

2/14/2025

Objective:

Reference(s):

Determine material sizing for embankment based on 2D hydraulic model results for existing conditions.

USACE (U.S. Army Corps of Engineers). 1994. Hydraulic Design of Flood Control Channels. Engineer Manual 1110-2-1601. 30 June 1994.

Calculated by: JV Checked by: AD Sheet No: 2 of 2

Estimate the gradation envelope using the D30 and Table 3-1 from USACE (1994)

D30 = 0.83 ft s = 165.00 lb/ft3

D30 (Lower) = 0.73 ft Table 3-1 D30 (Upper) = 0.85 ft Table 3-1

Gradation Envelope based on Table 3-1

Parameter Stone Weight

(lb)1 Particle

Diameter (in) Particle

Diameter (ft) Percent Finer

D100 (min.) 185 15.47 1.29 100 D50 (min.) 93 12.30 1.02 50 D15 (min.) 29 8.34 0.69 15

D100 (max.) 463 21.00 1.75 100 D50 (max.) 137 13.99 1.17 50 D15 (max.) 69 11.13 0.93 15

Recommended Armor Design:

Minimum D50 = 12.3 in Thickness (1*D100 (max)) = 21.0 in

Notes:

1. Interpolate values from Table 3-1

Objective: Determine material sizing for embankment based on 2D hydraulic model results for existing conditions.

Reference(s):

USACE (U.S. Army Corps of Engineers). 1994. Hydraulic Design of Flood Control Channels. Engineer Manual 1110-2- 1601. 30 June 1994.

USBR (U.S. Bureau of Reclamation). 2007. Stone Sizing Criteria. Technical Supplement 14C, National Engineering Handbook.

Project: Repair Storm Damage at Mora Road (95% Design) Project No: 194-1343-0002

Subject: Material Sizing Calculations - Embankment Date: 2/14/2025

0.00 0.50 1.00 1.50 2.00 2.50

Pe rc en t F in er

Particle Size (ft)

100-Year Riprap Gradation Envelope Using USACE 1994 Gradation Method

Lower Limit Upper Limit

Calculated by: JV Checked by: AD Sheet No: 1 of 2

Estimate D30

Equation: D30 = SfCsCvCt w s w))1/2 V/(K1gd)1/2}2.5 where: D30 = material size in which 30 percent is finer by weight [ft]

Define Input Parameters

Safety Factor Sf = 1.50 Minimum of 1.1, usually 1.1-1.5

Stability Coefficient for Incipient Failure Cs = 0.300 Typical for angular rock

Vertical velocity distribution coefficient Cv = 1.21 Conservative assumption of Cv=1.283-0.2*log(R/W) Centerline bend radius R = 840.00 ft Value used for bend scour analysis

Water surface width W = 350.00 ft Value used for bend scour analysis Ratio R/W = 2.4

Thickness coefficient Ct = 1.00 Assume 1 for 1*D100 or 1.5*D50

Flow depth d = 20.50 ft Average for existing riprap Specific weight of water w = 62.40 lb/ft3

Specific weight of stone s = 165.00 lb/ft3

Local velocity V = 6.06 ft/s Average for existing riprap Gravitational constant g = 32.20 ft/s2

Side slope correction factor K1 = 0.58 Use K1 curve recommended for design Side slope angle 39.0 deg Measured from terrain Angle of repose 40.0 deg Typically 40 degrees

Side slope velocity Vss = 9.35 ft/s Vss = V * {1.74 - 0.52*Log(R/W)}

Calculation Results:

D30 = 0.94 ft D30 = 11.32 Inches

Objective: Determine material sizing for existing riprap based on 2D hydraulic model results for existing conditions.

Reference(s):

USACE (U.S. Army Corps of Engineers). 1994. Hydraulic Design of Flood Control Channels. Engineer Manual 1110-2-1601. 30 June 1994.

USBR (U.S. Bureau of Reclamation). 2007. Stone Sizing Criteria. Technical Supplement 14C, National Engineering Handbook.

Project: Repair Storm Damage at Mora Road (95% Design) Project No: 194-1343-0002

Subject: Material Sizing Calculations - Existing Riprap Date: 2/14/2025

Calculated by: JV Checked by: AD Sheet No: 2 of 2

Estimate the gradation envelope using the D30 and Table 3-1 from USACE (1994)

D30 = 0.94 ft s = 165.00 lb/ft3

D30 (Lower) = 0.85 ft Table 3-1 D30 (Upper) = 0.97 ft Table 3-1

Gradation Envelope based on Table 3-1

Parameter Stone Weight

(lb)1 Particle

Diameter (in) Particle

Diameter (ft) Percent Finer

D100 (min.) 276 17.67 1.47 100 D50 (min.) 138 14.03 1.17 50 D15 (min.) 43 9.51 0.79 15

D100 (max.) 691 24.00 2.00 100 D50 (max.) 205 16.01 1.33 50 D15 (max.) 102 12.68 1.06 15

Recommended Armor Design:

Minimum D50 = 14.0 in Thickness (1*D100 (max)) = 24.0 in

Notes:

1. Interpolate values from Table 3-1

Project: Repair Storm Damage at Mora Road (95% Design) Project No: 194-1343-0002

Subject: Material Sizing Calculations - Existing Riprap Date: 2/14/2025

Objective: Determine material sizing for existing riprap based on 2D hydraulic model results for existing conditions.

Reference(s):

USACE (U.S. Army Corps of Engineers). 1994. Hydraulic Design of Flood Control Channels. Engineer Manual 1110- 2-1601. 30 June 1994.

USBR (U.S. Bureau of Reclamation). 2007. Stone Sizing Criteria. Technical Supplement 14C, National Engineering Handbook.

0.00 0.50 1.00 1.50 2.00 2.50

Pe rc en t F in er

Particle Size (ft)

100-Year Riprap Gradation Envelope Using USACE 1994 Gradation Method

Lower Limit Upper Limit

Scour

JV AD Sheet No:

FHWA (Federal Highway Administration). 2012. Hydraulic Engineering Circular No. 18 - Evaluating Scour at Bridges. Fifth Edition.

Federal Highway Administration. 2009. HEC-23, Bridge Scour and Stream Instability Countermeasures-Third Edition.

U.S. Army Corps of Engineers (USACE). 2021. Approaches for Assessing Riverine Scour.

General Scour (ft)

Pier Scour (ft)

Abutment Scour (ft) Bend Scour (ft)

Total Scour (General+Pier)

(ft)

Total Scour (Abut+Pier+Bend)

(ft)

12.9 3.2 8.7 7.8 16.1 19.7

12.9 3.8 8.7 7.8 16.7 20.3

12.9 3.8 8.7 7.8 16.7 20.3

Project: Repair Storm Damage at Mora Road (95% Design) Project No: 194-1343-0002

Subject: Total Scour Summary Date: 1/24/2025

NRCS (Natural Resources Conservation Service). 2007. Technical Supplement 14B, Scour Calculations.

Deflector

Calculated by: Checked by:

Structure Type

Large Deflector

Objective: Estimate total scour for the proposed design.

Reference(s):

Revetment Log

2/6/2025 P:\194-1343-0002 MORA ROAD REPAIR\Engineering\Analyses\Scour\95 Percent\MoraRoadRepair_General and Local Scour_95%.xlsx

Inputs

Inputs

Units Design Discharge Qd = 126,636

Return Interval 100-cubic feet per second [cfs] year + resiliency adjustment 3,586 cubic meters per second [m3/s]

Flow Width at Design Discharge Wf = 350 feet [ft] 107 meters [m]

Median Size of Bed Material D50 = 14 millimeters [mm] D50 = 0.05 ft

Channel Condition

Part 1: Calculate mean and maximum scour based on the Blodgett (1986) method zt (mean) = KD50 -0.1 ft = best fit curve (fig. TS14B-1) for observed scour (Eq. TS14B-21)1 where:

K (mean) = 1.42 = coefficient of 1.42 for D50 in ft or 0.84 for D50 in mm

D50 = 0.05 ft zt (mean) = 1.9 ft zt (max) = KD50 -0.11 ft = enveloping curve (fig. TS14B-1) for max scour (Eq. TS14B-22)1 where:

K (max) = 6.5 = coefficient of 6.5 for D50 in ft or 3.8 for D50 in mm

D50 = 0.05 ft zt (max) = 9.1 ft

Part 2: Calculate maximum scour using the Lacey (1931) and Blench (1970) methods as suggested by Pemberton and Lara (1984) zt (max) = KQd aWf bD50 c ft (Eq. TS14B-23)1 where:

K = coefficient based on units and channel condition (tables TS14B-8 and TS14B-9) a, b, c = constants based on channel condition (table TS14B-8)

Lacey Blench K = 0.2920 0.5300 a = 0.3333 0.6667 b = 0.0000 -0.6667 c = -0.1667 -0.1092 zt (max) = 9.4 20.2 ft

Table TS14B-8: Constants for Lacey and Blench relations, U.S. units (D50 in mm)

K a b c K a b c Straight reach 0.097 1/3 0.0000 - 1/6 0.530 2/3 - 2/3 -0.1092 Moderate bend 0.195 1/3 0.0000 - 1/6 0.530 2/3 - 2/3 -0.1092 Severe bend 0.292 1/3 0.0000 - 1/6 0.530 2/3 - 2/3 -0.1092 Right angle bend 0.389 1/3 0.0000 - 1/6 1.105 2/3 - 2/3 -0.1092 Vertical rock wall 0.487 1/3 0.0000 - 1/6

Table TS-14B-9: Constant K for Lacey and Blench relations, SI units (D50 in mm) Lacey Blench

K K Straight reach 0.030 0.162 Moderate bend 0.059 0.162 Severe bend 0.089 0.162 Right angle bend 0.119 0.337 Vertical rock wall 0.148 0.000

Objective:

Reference(s):

Project No:

Date:

Project: Repair Storm Damage at Mora Road (95% Design)

Subject: General Scour Calculations

Calculated by:

NRCS (Natural Resources Conservation Service). 2007. Technical Supplement 14B, Scour Calculations.

Checked by:

194-1343-0002

Estimate general scour for proposed design using NRCS calculation methods.

1/24/2025

English

Lacey Blench Condition

Condition

Severe bend

P:\194-1343-0002 MORA ROAD REPAIR\Engineering\Analyses\Scour\95 Percent\MoraRoadRepair_General and Local Scour_95%.xlsx

Inputs Structure Type

Units Pier Shape

Pier Length L= 1.3 feet [ft] 0.4 meters [m] Pier Width a= 1.3 ft 0.4 m

Upstream Flow Depth y1= 29 ft 8.8 m Upstream Average Velocity V1 = 2.5 feet per second [ft/s] 0.8 meters per second [m/s]

Median Size of Bed Material D50 = 14 millimeters [mm] D50 = 0.05 ft D95 = 117.5 millimeters [mm] D95 = 0.39 ft

Bed Conditions Dune Height 0 ft 0.0 m

Angle of attack 10 degrees

Calculate pier scour depth using the following relations:

(Eqns 7.1 and 7.3) where:

Correction factor for pier nose shape from Table 7.11 K1 = 1.0

Correction factor for angle of attack from Table 7.2 or Eqn 7.42 K2 = 1.1 Correction factor for bed condition from Table 7.3 K3 = 1.1

Acceleration of gravity g = 32.2 ft/s2 9.81 m/s2

Froude Number directly upstream of pier Fr1= 0.082 =V1/(g*y1)0.5

Scour depth ys= 3.18 ft 1.0 m

Table 7.1: Correction Factor, K1, for Pier Nose Shape1 Table 7.2: Correction Factor, K2, for Angle of Attack of the Flow2

Shape of Pier Nose K1 Angle L/a = 4 L/a = 8 L/a = 12 Square Nose 1.1 0 1.0 1.0 1.0 Round Nose 1.0 15 1.5 2.0 2.5 Cylindrical 1.0 30 2.0 2.8 3.5

Group of Cylinders 1.0 45 2.3 3.3 4.3 Sharp Nose 0.9 90 2.5 3.9 5.0

(Eqn 7.4) Table 7.3: Increase in Equilibrium Pier Scour Depths, K3, for Bed Condition

Bed Condition Dune Height (ft) K3 Clear-Water Scour N/A 1.1

Plane Bed/Antidune N/A 1.1 Small Dunes 10 > H 1.1

Medium Dunes 30 > H 1.2 Large Dunes H 1.3

Notes

1. Table 7.1 valid for 1 = 1.0.

2. If L/a > 12, then use L/a = 12. Maximum of K2 = 5.0.

Project: Repair Storm Damage at Mora Road (95% Design) Project No: 194-1343-0002

Subject: Pier Scour - Large Deflector Structure Date: 1/24/2025

Objective: Estimate local scour for proposed design using FHWA calculation methods.

Reference(s):

FHWA (Federal Highway Administration). 2012. Hydraulic Engineering Circular No. 18 - Evaluating Scour at Bridges. Fifth Edition.

Large Deflector English

Clear-Water Scour

Cylindrical

Calculated by: Checked by:

P:\194-1343-0002 MORA ROAD REPAIR\Engineering\Analyses\Scour\95 Percent\MoraRoadRepair_General and Local Scour_95%.xlsx

Inputs Structure Type

Units Pier Shape

Pier Length L= 1.3 feet [ft] 0.4 meters [m] Pier Width a= 1.3 ft 0.4 m

Upstream Flow Depth y1= 29 ft 8.8 m Upstream Average Velocity V1 = 3.7 feet per second [ft/s] 1.1 meters per second [m/s]

Median Size of Bed Material D50 = 14 millimeters [mm] D50 = 0.05 ft D95 = 117.5 millimeters [mm] D95 = 0.39 ft

Bed Conditions Dune Height 0 ft 0.0 m

Angle of attack 10 degrees

Calculate pier scour depth using the following relations:

(Eqns 7.1 and 7.3) where:

Correction factor for pier nose shape from Table 7.11 K1 = 1.0

Correction factor for angle of attack from Table 7.2 or Eqn 7.42 K2 = 1.1 Correction factor for bed condition from Table 7.3 K3 = 1.1

Acceleration of gravity g = 32.2 ft/s2 9.81 m/s2

Froude Number directly upstream of pier Fr1= 0.121 =V1/(g*y1)0.5

Scour depth ys= 3.76 ft 1.1 m

Table 7.1: Correction Factor, K1, for Pier Nose Shape1 Table 7.2: Correction Factor, K2, for Angle of Attack of the Flow2

Shape of Pier Nose K1 Angle L/a = 4 L/a = 8 L/a = 12 Square Nose 1.1 0 1.0 1.0 1.0 Round Nose 1.0 15 1.5 2.0 2.5 Cylindrical 1.0 30 2.0 2.8 3.5

Group of Cylinders 1.0 45 2.3 3.3 4.3 Sharp Nose 0.9 90 2.5 3.9 5.0

(Eqn 7.4) Table 7.3: Increase in Equilibrium Pier Scour Depths, K3, for Bed Condition

Bed Condition Dune Height (ft) K3 Clear-Water Scour N/A 1.1

Plane Bed/Antidune N/A 1.1 Small Dunes 10 > H 1.1

Medium Dunes 30 > H 1.2 Large Dunes H 1.3

Notes

1. Table 7.1 valid for 1 = 1.0.

2. If L/a > 12, then use L/a = 12. Maximum of K2 = 5.0.

Project: Repair Storm Damage at Mora Road (95% Design) Project No: 194-1343-0002

Subject: Pier Scour - Deflector Structure Date: 1/24/2025

Objective: Estimate local scour for proposed design using FHWA calculation methods.

Reference(s):

FHWA (Federal Highway Administration). 2012. Hydraulic Engineering Circular No. 18 - Evaluating Scour at Bridges. Fifth Edition.

Deflector English

Cylindrical

Clear-Water Scour

Calculated by: Checked by:

P:\194-1343-0002 MORA ROAD REPAIR\Engineering\Analyses\Scour\95 Percent\MoraRoadRepair_General and Local Scour_95%.xlsx

Inputs Structure Type

Units Pier Shape

Pier Length L= 1.3 feet [ft] 0.4 meters [m] Pier Width a= 1.3 ft 0.4 m

Upstream Flow Depth y1= 29 ft 8.8 m Upstream Average Velocity V1 = 3.7 feet per second [ft/s] 1.1 meters per second [m/s]

Median Size of Bed Material D50 = 14 millimeters [mm] D50 = 0.05 ft D95 = 117.5 millimeters [mm] D95 = 0.39 ft

Bed Conditions Dune Height 0 ft 0.0 m

Angle of attack 10 degrees

Calculate pier scour depth using the following relations:

(Eqns 7.1 and 7.3) where:

Correction factor for pier nose shape from Table 7.11 K1 = 1.0

Correction factor for angle of attack from Table 7.2 or Eqn 7.42 K2 = 1.1 Correction factor for bed condition from Table 7.3 K3 = 1.1

Acceleration of gravity g = 32.2 ft/s2 9.81 m/s2

Froude Number directly upstream of pier Fr1= 0.121 =V1/(g*y1)0.5

Scour depth ys= 3.76 ft 1.1 m

Table 7.1: Correction Factor, K1, for Pier Nose Shape1 Table 7.2: Correction Factor, K2, for Angle of Attack of the Flow2

Shape of Pier Nose K1 Angle L/a = 4 L/a = 8 L/a = 12 Square Nose 1.1 0 1.0 1.0 1.0 Round Nose 1.0 15 1.5 2.0 2.5 Cylindrical 1.0 30 2.0 2.8 3.5

Group of Cylinders 1.0 45 2.3 3.3 4.3 Sharp Nose 0.9 90 2.5 3.9 5.0

(Eqn 7.4) Table 7.3: Increase in Equilibrium Pier Scour Depths, K3, for Bed Condition

Bed Condition Dune Height (ft) K3 Clear-Water Scour N/A 1.1

Plane Bed/Antidune N/A 1.1 Small Dunes 10 > H 1.1

Medium Dunes 30 > H 1.2 Large Dunes H 1.3

Notes

1. Table 7.1 valid for 1 = 1.0.

2. If L/a > 12, then use L/a = 12. Maximum of K2 = 5.0.

Revetment English

Cylindrical

Clear-Water Scour

Calculated by: Checked by: 5 of 7

Objective: Estimate local scour for proposed design using FHWA calculation methods.

Reference(s):

FHWA (Federal Highway Administration). 2012. Hydraulic Engineering Circular No. 18 - Evaluating Scour at Bridges. Fifth Edition.

Project: Repair Storm Damage at Mora Road (95% Design) Project No: 194-1343-0002

Subject: Pier Scour - Revetment Structure Date: 1/24/2025

P:\194-1343-0002 MORA ROAD REPAIR\Engineering\Analyses\Scour\95 Percent\MoraRoadRepair_General and Local Scour_95%.xlsx

Inputs Units

Abutment Shape Length of active flow obstructed by embankment L'= 40.0 feet [ft] 12.2 meters [m] Length of embankment projected normal to flow L = 80.0 ft 24.4 m

Flow area of approach cross section obstructed by embankment Ae= 1,285.0 ft2 119.4 m2

Average channel flow depth y1= 29 ft 8.8 m Average floodplain flow depth ya = 16.1 ft 4.9 m

Flow obstructed by abutment and approach embankment Qe= 4600 ft3/s 130.3 m3/s Velocity upstream of embankment Ve = 2.5 feet per second [ft/s] 0.8 meters per second [m/s]

Abutment Angle (Figure 8.5)1 90 degrees

Calculate abutment scour using Froelich (TRB 1989) method:

(Eqn. 8.1) where:

Coefficient for abutment shape from Table 8.1 K1 = 0.55

Coefficient for angle of embankment to flow1 K2 = 1.00 0.13

Acceleration of gravity g = 32.2 ft/s2 9.81 m/s2

Froude Number directly upstream abutment Fr1= 0.110 =Ve/(g*ya) 0.5

Abutment Scour Depth ys= 8.72 ft 2.7 m

Table 8.1: Abutment Shape Coefficients Description K1

Vertical Wall 1.00 Vertical Wall with Wing Walls 0.82

Spill-Through 0.55

Notes

1. If embankment points downstream, Project: Repair Storm Damage at Mora Road (95% Design) Project No: 194-1343-0002

Subject: Abutment Scour Calculations Date: 1/24/2025

Objective: Estimate abutment scour for proposed design using FHWA calculation methods.

Reference(s):

FHWA (Federal Highway Administration). 2012. Hydraulic Engineering Circular No. 18 - Evaluating Scour at Bridges. Fifth Edition.

English Spill-Through

Calculated by: Checked by: 6 of 7

P:\194-1343-0002 MORA ROAD REPAIR\Engineering\Analyses\Scour\95 Percent\MoraRoadRepair_General and Local Scour_95%.xlsx

Method 1 - Maynord Equation Notes:

Developed using high discharges within the channel banks with return intervals of 1-5 years. Overbank depth should be less than 20% of channel depth.

Developed on sand bed streams but agrees reasonably well with limited number of gravel bed data points.

Rc/W from 1.5 to 10 W/Dmnc from 20 to 125

Inputs:

Centerline Radius of the Bend Rc = 840.0 ft

Width of bend W = 350 ft Cross Sectional Area A = 2400.0 ft2

Calculations:

Average water depth upstream of bend Dmnc = 6.9 ft

If Rc mnc

Ratio Ratio used in calculation:

Rc/W 2.4 2.4

W/Dmnc 51.0 51.0

Results:

Maximum Depth of water in the bend Dmxb = 14.4 ft Depth of additional scour below thalweg Scour Depth = 7.6 ft

Method 2 - Thorne Equation Notes:

Developed using high, steady, in-bank flows. Care must be taken if used to calculate scour for greater than bankfull stage.

Encompasses materials ranging from sand to boulders.

Inputs:

Bend radius of curvature Rc = 840.0 ft

Channel top width of upstream cross section W = 350 ft Cross Sectional Area A = 2400.0 ft2

Calculations:

Mean depth of upstream cross section dhUS = 6.9 ft

Rc/W = 2.4 Depth of scour below thalweg Scour Depth 8.5 ft

Reference(s):

Federal Highway Administration. 2009. HEC-23, Bridge Scour and Stream Instability Countermeasures-Third Edition.

U.S. Army Corps of Engineers (USACE). 2021. Approaches for Assessing Riverine Scour.

Project: Repair Storm Damage at Mora Road (95% Design) Project No: 194-1343-0002

Subject: Bend Scour Calculations Date: 1/28/2025

Calculated by: Checked by: 7 of 7

Objective: Estimate bend scour for proposed design.

P:\194-1343-0002 MORA ROAD REPAIR\Engineering\Analyses\Scour\95 Percent\MoraRoadRepair_General and Local Scour_95%.xlsx

Reference(s):

Federal Highway Administration. 2009. HEC-23, Bridge Scour and Stream Instability Countermeasures-Third Edition.

U.S. Army Corps of Engineers (USACE). 2021. Approaches for Assessing Riverine Scour.

Project: Repair Storm Damage at Mora Road (95% Design) Project No: 194-1343-0002

Subject: Bend Scour Calculations Date: 1/28/2025

Calculated by: Checked by: 7 of 7

Objective: Estimate bend scour for proposed design.

USACE Equation Notes:

Engineer Manual 1110-2-1601, Plate B41 Sand or gravel rivers (separate equation for each)

Inputs:

Bend radius of curvature Rc = 840.0 ft

Channel top width of upstream cross section W = 350 ft Cross Sectional Area A = 2400.0 ft2

Max depth in design cross section Dmax = 11.5 ft

Calculations:

Mean depth of upstream cross section dhUS = 6.9 ft

Rc/W = 2.4 Depth of scour below thalweg Scour Depth 7.4 ft for gravel bed rivers

Average scour depth of three methods 7.8 ft

P:\194-1343-0002 MORA ROAD REPAIR\Engineering\Analyses\Scour\95 Percent\MoraRoadRepair_General and Local Scour_95%.xlsx

Large Wood Structure Stability

Calculated by: JV Checked by: AD

Large Deflector Structures - Example Design Details

Large Deflector Structures - Example As-Built Photos

Inputs in blue cells

Inputs

Public Safety Risk High Property Damage Risk High Stability Design Flow Criteria 100-year

Factor of Safety Summary

PParameter Targett FS Designn FS Doess Designn

Meett Target??

(Y/N)

Sliding 1.75 10.15 Y Buoyancy 2.00 2.00 Y Rotation 1.75 1.77 Y

Overturning 1.75 1.93 Y

Sheet No:

194-1343-0002

2/7/2025

Project: Repair Storm Damage at Mora Road (95% Design)

Subject: Large Wood Stability Calculations - Large Deflectors

Project No:

Date:

Objective:

Reference(s):

Summary of large wood stability calculations for large deflector structures.

USBR (U.S. Bureau of Reclamation) & USACE (U.S. Army Corps of Engineers). 2016. National Large Wood Manual - Assessment, Planning, Design, and Maintenance of Large Wood in Fluvial Ecosystems: Restoring Process, Function, and Structure.

USBR. 2014. Large Woody Material - Risk Based Design Guidelines. Reclamation, Managing Water in the West. Pacific Northwest Region Resource & Technical Services.

Inputs in blue cells

Material Properties Median particle diameter D50 = 0.046 ft w = 62.4 lb/ft3 solid = 165 lb/ft3

Unit Weight of Dry Soil Backfill d= 120 lb/ft3

Void Ratio e = 0.38 Porosity n = 0.27 Degree of Saturation Below Water Level S = 100% Weight of Pore Water per ft3 of Sample w = 17.02 lb/ft3

Saturated Unit Weight of Soil sat ( s) = 137.02 lb/ft3

Buoyant (effective) Unit Weight of Soil Backfill soil '= 74.62 lb/ft3 ss = 2.64 Specifc Gravity of Boulders sb = 2.66 Unit Weight of Boulders bou = 146 lb/ft3

Unit Weight of Wood wood = 41 lb/ft3

Coefficients Lift Coefficient CL = 1.5 Drag Coefficient CD = 1.5 Coefficient of Importance Ci = 1 Coefficient of Orientation Co = 0.8 Coefficient of Depth Cd = 1 Coefficient of Blockage Cb = 1 Coefficient of lateral earth pressure ks = 1

Other g = 32.2 ft/s2

Bed Sediment Internal Friction Angle = 36 Degrees Response Ratio for impulsive Loads Rmax = 0.8

Objective: Inputs for general material properties and select constants to be used in subsequent large wood stability calculations.

Reference(s):

USBR (U.S. Bureau of Reclamation) & USACE (U.S. Army Corps of Engineers). 2016. National Large Wood Manual - Assessment, Planning, Design, and Maintenance of Large Wood in Fluvial Ecosystems: Restoring Process, Function, and Structure.

USBR. 2014. Large Woody Material - Risk Based Design Guidelines. Reclamation, Managing Water in the West. Pacific Northwest Region Resource & Technical Services.

Sheet No:

194-1343-0002

Subject: Large Wood Stability Calculations - Large Deflectors Date: 2/7/2025

Project: Repair Storm Damage at Mora Road (95% Design) Project No:

Specific Gravity of Soil

Acceleration due to Gravity

Soil Solid Density Water Density

To estimate the buoyancy force of the wood:

To estimate the effective weight per submerged boulder:

Inputs in blue cells Structure Information - Large Wood

Key "Base" Members Stacked "Middle"

Members Top Members Units hemlock, western hemlock, western hemlock, western

SL = 0.42 0.42 0.42

NL = 18 30 18

DRW = 4 4 4 ft LRW = 4 4 4 ft p = 0.2 0.2 0.2 decimal % DL = 2 2 2 ft

L = 45 45 45 ft V = 142 142 142 ft3

Vtot = 2,560 4,266 2,560 ft3

FBL = 92,643 154,405 92,643 lb

Structure Information - Ballast (Boulders)

Minimum Boulder Size Maximum Boulder Size UUnits

Equivalent Diameter of Boulder DB = 3 4 ft Number of Boulders Submerged NB = 0 0

Number of Boulders Unsubmerged NBU = 0 0 Effective Weight Per Submerged Boulder W' = 1,464 3,471 lb

W = 2,347 5,562 lb Wtot = 0 0 lb

Structure Information - Ballast (Soil) Value Units

Nominal Footprint Area of Soil Backfill ABF= 1261 ft2

ZB = 16 ft Depth of Soil Backfill Unsubmerged ZBU = 0 ft

Vd = 9,386 ft3

Effective (submerged) Weight of Soil Ballast W' = 804,959 lb Unsubmerged (Dry) Weight of Soil Ballast W = 0 lb

Wtot = 804,959 lb

Structure Information - Vertical Piles Number of Vertical Piles in Structure Npiles = 28 Length of Pile Below Scoured Bed Lem= 3 ft Pile Diameter Dp = 1.3 ft

Structure Information - Floating Debris Weight Wdeb = 6000 lbs

Sheet No: 3 of 8

Objective: Inputs for structure specifications to be used in subsequent large wood stability calculations.

Reference(s):

USBR (U.S. Bureau of Reclamation) & USACE (U.S. Army Corps of Engineers). 2016. National Large Wood Manual - Assessment, Planning, Design, and Maintenance of Large Wood in Fluvial Ecosystems: Restoring Process, Function, and Structure.

USBR. 2014. Large Woody Material - Risk Based Design Guidelines. Reclamation, Managing Water in the West. Pacific Northwest Region Resource & Technical Services.

Project: Repair Storm Damage at Mora Road (95% Design) Project No: 194-1343-0002

Subject: Large Wood Stability Calculations - Large Deflectors Date: 2/7/2025

Property

Total Volume of Wood

Total Effective Weight

Property

Weight Per Boulder Total Effective Weight

Depth of Soil Backfill Submerged

Average Rootwad Length

Total Volume Volume Per Member

Net Buoyancy Force

Proportion of Voids in Rootwad Tree Stem Average Diameter

Tree Stem Average Length

Property

Wood Type

Number of Logs with Rootwads Specific Gravity of Wood

Average Rootwad Fan Diameter

NL

Design scenario 100-year

Water Depth on Structure Water Depth on Upstream Face of Wood Structure Yu = 16 feet

Water Depth on Downstream Face of Wood Structure Yd = 16 feet

Velocity Approach Velocity Uo = 6 ft/s

Channel Velocity Vc = 6 ft/s Contracted Section Velocity Uc = 6 ft/s

Submerged Structure Area Perpendicular to Flow Upstream Downstream

Width w = 75 75 feet Depth Y = 16 16 feet

Cross-Sectional Area A = 1200 1200 ft2

Other Distance Above Scoured Bed Applied Load hload= 20 feet

Length from tip to point of rotation (1) Lsp = 75 feet Mean distance of piles to point of rotation (2) Lph = 37 feet

Length of structure parallel to flow Ls = 115 feet

Upstream depth to point of rotation(3) dubury = 4 feet Downstream depth to point of rotation(4) ddbury = 4 feet

Mean Distance from Piles to Point of Rotation (5) Lpv = 50 feet

Bank Embedment Embedded length of structure (6) Lebp = 12 feet

Mean Depth of submerged soil above embedded logs Dsub = 6 feet Number of logs embedded into bank 16

Mean Depth of dry soil above embedded logs Ddry = 0 feet

Channel Embedment Embedded length of structure (6) Lebp = 75 feet

Mean Depth of submerged soil above embedded logs Dsub = 2 feet Number of logs embedded into channel bed 9

Mean Depth of dry soil above embedded logs Ddry = 0 feet

Notes

(1) Length of wood structure from tip in the river to point of rotation in the bank measured perpendicular to flow

(2) Measured perpendicular to flow

(3) Depth at upstream side of structure from channel bottom to point of rotation measured perpendicular to flow

(4) Depth at downstream side of structure from channel bottom to point of rotation measured perpendicular to flow

(5) Measured parallel to flow

(6) Embedded length of wood structure measured perpendicular to flow

Objective: 2D hydraulic modeling results inputs for the design scenario to be used in subsequent large wood stability calculations.

Reference(s):

USBR (U.S. Bureau of Reclamation) & USACE (U.S. Army Corps of Engineers). 2016. National Large Wood Manual - Assessment, Planning, Design, and Maintenance of Large Wood in Fluvial Ecosystems: Restoring Process, Function, and Structure.

USBR. 2014. Large Woody Material - Risk Based Design Guidelines. Reclamation, Managing Water in the West. Pacific Northwest Region Resource & Technical Services.

Sheet No:

194-1343-0002

Subject: Large Wood Stability Calculations - Large Deflectors Date: 2/7/2025

Project: Repair Storm Damage at Mora Road (95% Design) Project No:

Factor of Safety Against Buoyancy

Lift:

Assumptions:

Logs and ballast in structure are fully submerged.

Structure acts as composite structure and is assumed to be fully connected.

Structure can move freely vertically without any binding to the piles.

Lift Force:

Area Perpendicular to Flow A = 1,200 ft2

Approach Velocity Uo = 6.0 ft/s Lift Coefficient CL = 1.5

Lift Force FL = 62,788 lb

Buoyancy Force:

Key "Base" Members 92,643 lb

Stacked "Middle" Members 154,405 lb Top Members 92,643 lb

Total Buoyancy Force FBL = 339,692 lb

Ballast Forces:

Dry wood FLWMd = 0 lb Boulders Fboulders = 0 lb Soil Fsoil = 804,959 lb Total Ballast 804,959 lb

Factor of Safety Against Buoyancy:

FOSb = 2.00

Reference(s):

USBR (U.S. Bureau of Reclamation) & USACE (U.S. Army Corps of Engineers). 2016. National Large Wood Manual - Assessment, Planning, Design, and Maintenance of Large Wood in Fluvial Ecosystems: Restoring Process, Function, and Structure.

USBR. 2014. Large Woody Material - Risk Based Design Guidelines. Reclamation, Managing Water in the West. Pacific Northwest Region Resource & Technical Services.

Project: Repair Storm Damage at Mora Road (95% Design) Project No: 194-1343-0002

Subject: Large Wood Stability Calculations - Large Deflectors Date: 2/7/2025

Sheet No: 5 of 8

Objective: Factor of safety calculations for buoyancy.

Horizontal Forces - Friction, Drag, Impact

Lift: Normal: Friction:

Drag: Impact:

Calculation Parameters

Bed Sediment Friction Angle 36 degrees Bed Stress μbed= 0.73

Submerged Weight of Ballast Wbl(sub)= 804,959 pounds Buoyancy Force Fb = 339,692 pounds

Area Perpendicular to Flow A = 1,200 ft2

Approach Velocity Uo = 6.0 ft/s Drag Coefficient CD = 1.5

Calculation Parameters - Impact Force Weight of debris wdebris = 6000 lbs Channel velocity Vchannel = 6 ft/s

Coefficient of importance Ci = 1 Coefficient of orientation Co = 0.8

Coefficient of depth Cd = 1 Coefficient of blockage Cb = 1

Response ratio for impulsive loads Rmax = 0.8

Acceleration due to gravity g = 32.2 ft/s2

Time from initial velocity to zero velocity 0.03 s

Summary of Forces Force (lbs)

Lift FL= 62,788 Normal Fn= 402,479 Friction Ff= 292,418 Drag Fd= 62,788 Impact Fi= 37,465

Lateral Resistance Forces - Vertical Pilings and Passive Force

Calculation Parameters Number of Vertical Piles N = 28

Sheet No: 6 of 8

Type

Project: Repair Storm Damage at Mora Road (95% Design) Project No: 194-1343-0002

Subject: Large Wood Stability Calculations - Large Deflectors Date: 2/7/2025

Objective: Factor of safety calculations for sliding.

Reference(s):

USBR (U.S. Bureau of Reclamation) & USACE (U.S. Army Corps of Engineers). 2016. National Large Wood Manual - Assessment, Planning, Design, and Maintenance of Large Wood in Fluvial Ecosystems: Restoring Process, Function, and USBR. 2014. Large Woody Material - Risk Based Design Guidelines. Reclamation, Managing Water in the West. Pacific Northwest Region Resource & Technical Services.

Length of Pile Below Scoured Bed Lem= 3.0 ft Pile Diameter Dp = 1.3 ft

Distance Above Scoured Bed Applied Load hload= 20.0 ft

Rankine Coefficient of Passive Earth Pressure: Kp = 3.85

Horizontal Restraint Force from Piles:

Fgh(piles) = 6,141 lbs

Passive Force from Embeddment:

Calculation Parameters - Bank Embedment Mean Depth of dry soil above embedded logs Ddry = 0

Embedded length of structure Lebp = 12 ft Diameter of logs dlog = 2 ft

Number of embedded logs 16 Mean Depth of submerged soil above embedded logs Dsub = 6 ft v = 448 lb/ft2

Fpassive, bank = 331,105 lb

Calculation Parameters - Channel Embedment Mean Depth of dry soil above embedded logs Ddry = 0

Embedded length of structure Lebp = 75 Diameter of logs dlog = 2

Number of embedded logs 9 Mean Depth of submerged soil above embedded logs Dsub = 2 v = 149

Fpassive,bed = 388,013 lb

Assumptions

(1) Average diameter of all logs assumed to apply to logs embedded into the bank.

(2) Key base members that are perpendicular to flow (half of them) are assumed to be embedded in the channel.

(3) Average depths of embedment applied to logs embedded in the bank and channel bed.

Factor of Safety - Sliding

Fsliding = 10.15

Factor of Safety for Rotation

Sum of Driving Moments, MDrotation where:

Fi = impact force Fd = drag force

Fhu = hydrostatic force on upstream side of wood structure Lsp = length of wood structure from tip to point of rotation measured perpendicular to flow

Lebp = embedded length of wood structure measured perpendicular to flow

Force Equations Impact: Drag:

Hydrostatic:

Calculation Parameters Unit weight of water γw = 62.4 lb/ft3

Water Depth on Upstream Face of Wood Structure Yu = 16 ft Upstream area projected normal to flow Au = 1200 ft2

Length from tip to point of rotation Lsp = 75 ft Embedded length of structure Lebp = 12 ft

Summary of Forces Force (lbs)

Impact Fi= 37,465 Drag Fd= 62,788 Hydrostatic Fhu= 599,040

MDrotation = 30,419,225 lb-ft

Sum of Reacting Moments, MRrotation where:

Fhd = hydrostatic force on downstream side of wood structure

Fpassive = passive force acting against drag force due to material behind structure Ff = force due to friction

Fpile-h = force of lateral resistance from piles Lph = Mean distance of piles to point of rotation, measured perpendicular to flow

Force Equations Passive Force from Embedment:

Hydrostatic:

Friction:

Piles:

Reference(s):

USBR (U.S. Bureau of Reclamation) & USACE (U.S. Army Corps of Engineers). 2016. National Large Wood Manual - Assessment, Planning, Design, and Maintenance of Large Wood in Fluvial Ecosystems: Restoring Process, Function, and Structure.

USBR. 2014. Large Woody Material - Risk Based Design Guidelines. Reclamation, Managing Water in the West. Pacific Northwest Region Resource & Technical Services.

Type

Sheet No: 7 of 8

Objective: Factor of safety calculations for rotation.

Project: Repair Storm Damage at Mora Road (95% Design) Project No: 194-1343-0002

Subject: Large Wood Stability Calculations - Large Deflectors Date: 2/7/2025

𝑀𝑅ோ௧௧ ൌ 𝐹ௗ ∗

𝐿௦ 𝐿

𝐹௦௦௩, ∗

𝐿

𝐹௦௦௩,ௗ ∗ 𝐿௦ 𝐹 ∗

𝐿௦ 𝐹ି ∗ 𝐿

Calculation Parameters Unit weight of water γw = 62.4 lb/ft3

Downstream water depth Yd = 16 ft Downstream area projected normal to flow Ad = 1200 ft2

Summary of Forces

Force (lbs) Distance from

POR (ft) Hydrostatic Fhd= 599,040 43.5 Passive Bank Fpassive, bank= 331,105 6 Passive Bed Fpassive, bed= 388,013 37.5 Friction Ff = 292,418 37.5

Lateral Pile Fpile-h= 6,141 37

MRrotation = 53,788,262 lb-ft

FOSrotation = 1.77

Type

Factor of Safety for Overturning

Sum of Driving Moments, MDoverturn where:

Fi = impact force

Yu = depth on upstream face of structure Fd = drag force

Fhu = hydrostatic force on upstream side of wood structure dubury = depth at upstream side of structure from channel bottom to point of rotation measured perpendicular to flow

FL = lift force Fb = buoyancy force LS = length of structure measured parallel to flow

Calculation Parameters Impact force Fi = 37,465 lbs

Upstream Water depth Yu = 16 ft Drag force Fd = 62,788 lbs

Upstream hydrostatic force Fhu = 599,040 lbs Upstream depth to point of rotation dubury = 4 ft

Lift force FL = 62,788 lbs Buoyant Force Fb = 339,692 lbs

Structure length parallel to flow LS = 115 ft

MDoverturn = 30,236,347 lbs

Sum of Reacting Moments, MRoverturn where:

Fhd = hydrostatic force on downstream side of wood structure Yd = depth at downstream side of structure ddbury = depth at downstream side of structure from channel bottom to point of rotation measured perpendicular to flow Fpassive = Passive force Fballast = Force from weight of the ballast material Fpiles-v = Pile skin friction force

Lpv = Mean distance from piles to point of rotation Ls = Length of structure parallel to flow

Calculate pile skin friction force where:

dpiles = diameter of piles Lpiles = embedded length of piles after scour ks = coefficient of lateral earth pressure φ = internal angle of friction of soils γwood = unit weight of wood γsat = saturated unit weight of soil γw = unit weight of water

Calculation Parameters Npiles = number of vertical piles

Number of piles Npiles = 28 Pile diameter dpiles = 1.3 ft

Pile length Lpiles = 3 ft Coefficient of lateral earth pressure ks = 1

Internal friction angle φ = 36 degrees Unit weight of wood γwood = 41 lb/ft3

Reference(s):

USBR (U.S. Bureau of Reclamation) & USACE (U.S. Army Corps of Engineers). 2016. National Large Wood Manual - Assessment, Planning, Design, and Maintenance of Large Wood in Fluvial Ecosystems: Restoring Process, Function, and Structure.

USBR. 2014. Large Woody Material - Risk Based Design Guidelines. Reclamation, Managing Water in the West. Pacific Northwest Region Resource & Technical Services.

Sheet No: 8 of 8

Objective: Factor of safety calculations for overturning.

Project: Repair Storm Damage at Mora Road (95% Design) Project No: 194-1343-0002

Subject: Large Wood Stability Calculations - Large Deflectors Date: 2/7/2025

𝑀𝐷௩௧௨ ൌ 𝐹 ∗ 𝑌௨ 𝑑௨௨௬ 𝐹ௗ ∗

𝑌௨ 𝑑௨௨௬ 𝐹௨ ∗

𝑌௨ 𝑑௨௨௬ 𝐹 𝐹 ∗

𝐿௦

𝑀𝑅௩௧௨ ൌ 𝐹ௗ ∗

𝑌ௗ 𝑑ௗ௨௬ 𝐹௦௦௩,ௗ ∗ 𝑑ௗ௨௬ 𝐹௦௦௩, ∗

𝑌ௗ 𝑑ௗ௨௬

𝐹ି௩ ∗ 𝐿௩ 𝐹௦௧ ∗ 𝐿௦

Saturated unit weight of soil γsat = 137.02 lb/ft3

Unit weight of water γw = 62.4 lb/ft3 σ' = 224 lb/ft2

Fpiles-v = 31,806 lbs

Calculate sum of reacting moments

Calculation Parameters Downstream hydrostatic force Fhd = 599,040 lb

Downstream depth Yd = 16 ft Downstream depth at point of rotation ddbury = 4 ft

Passive force in banks Fpassive,bank = 331,105 lb Passive force in bed Fpassive,bed = 388,013 lb

Fballast = 804,959 lb Lpv= 50 ft

MRoverturn = 58,329,544 lbs

FOSoverturn = 1.93

Deflector Structures - Example Design Details

Deflector Structures - Example As-Built Photos

Inputs in blue cells

Inputs

Public Safety Risk High Property Damage Risk High Stability Design Flow Criteria 100-year

Factor of Safety Summary

PParameter Targett FS Designn FS Doess Designn

Meett Target??

(Y/N)

Sliding 1.75 6.51 Y Buoyancy 2.00 5.99 Y Rotation 1.75 1.75 Y

Overturning 1.75 3.30 Y

Sheet No:

194-1343-0002

2/7/2025

Project: Repair Storm Damage at Mora Road (95% Design)

Subject: Large Wood Stability Calculations - Deflectors

Project No:

Date:

Objective:

Reference(s):

Summary of large wood stability calculations for deflector structures.

USBR (U.S. Bureau of Reclamation) & USACE (U.S. Army Corps of Engineers). 2016. National Large Wood Manual - Assessment, Planning, Design, and Maintenance of Large Wood in Fluvial Ecosystems: Restoring Process, Function, and Structure.

USBR. 2014. Large Woody Material - Risk Based Design Guidelines. Reclamation, Managing Water in the West. Pacific Northwest Region Resource & Technical Services.

Material Properties Median particle diameter D50 = 0.046 ft w = 62.4 lb/ft3 solid = 165 lb/ft3

Unit Weight of Dry Soil Backfill d= 120 lb/ft3

Void Ratio e = 0.38 Porosity n = 0.27 Degree of Saturation Below Water Level S = 100% Weight of Pore Water per ft3 of Sample w = 17.02 lb/ft3

Saturated Unit Weight of Soil sat ( s) = 137.02 lb/ft3

Buoyant (effective) Unit Weight of Soil Backfill soil '= 74.62 lb/ft3 ss = 2.64 Specifc Gravity of Boulders sb = 2.66 Unit Weight of Boulders bou = 146 lb/ft3

Unit Weight of Wood wood = 41 lb/ft3

Coefficients Lift Coefficient CL = 1.5 Drag Coefficient CD = 1.5 Coefficient of Importance Ci = 1 Coefficient of Orientation Co = 0.8 Coefficient of Depth Cd = 1 Coefficient of Blockage Cb = 1 Coefficient of lateral earth pressure ks = 1

Other g = 32.2 ft/s2

Bed Sediment Internal Friction Angle = 36 Degrees Response Ratio for impulsive Loads Rmax = 0.8

Objective: Inputs for general material properties and select constants to be used in subsequent large wood stability calculations.

Reference(s):

USBR (U.S. Bureau of Reclamation) & USACE (U.S. Army Corps of Engineers). 2016. National Large Wood Manual - Assessment, Planning, Design, and Maintenance of Large Wood in Fluvial Ecosystems: Restoring Process, Function, and Structure.

USBR. 2014. Large Woody Material - Risk Based Design Guidelines. Reclamation, Managing Water in the West. Pacific Northwest Region Resource & Technical Services.

Sheet No:

194-1343-0002

Subject: Large Wood Stability Calculations - Deflectors Date: 2/7/2025

Project: Repair Storm Damage at Mora Road (95% Design) Project No:

Specific Gravity of Soil

Acceleration due to Gravity

Soil Solid Density Water Density

To estimate the effective weight per submerged boulder:

Inputs in blue cells Structure Information - Large Wood

Key "Base" Members Stacked "Middle"

Members Top Members Units hemlock, western hemlock, western hemlock, western

SL = 0.42 0.42 0.42

NL = 10 25 0

DRW = 4 4 0 ft LRW = 4 4 0 ft p = 0.2 0.2 0.2 decimal % DL = 2 2 1.5 ft

L = 45 45 30 ft V = 142 142 53 ft3

Vtot = 1,422 3,555 0 ft3

FBL = 51,468 128,671 0 lb

Structure Information - Ballast (Boulders)

Minimum Boulder Size Maximum Boulder Size UUnits

Equivalent Diameter of Boulder DB = 3 4 ft Number of Boulders Submerged NB = 0 0

Number of Boulders Unsubmerged NBU = 0 0 Effective Weight Per Submerged Boulder W' = 1,464 3,471 lb

W = 2,347 5,562 lb Wtot = 0 0 lb

Structure Information - Ballast (Soil) Value Units

Nominal Footprint Area of Soil Backfill ABF= 1600 ft2

ZB = 23 ft Depth of Soil Backfill Unsubmerged ZBU = 0 ft

Vd = 4,977 ft3

Effective (submerged) Weight of Soil Ballast W' = 2,374,853 lb Unsubmerged (Dry) Weight of Soil Ballast W = 0 lb

Wtot = 2,374,853 lb

Structure Information - Vertical Piles Number of Vertical Piles in Structure Npiles = 14 Length of Pile Below Scoured Bed Lem= 5 ft Pile Diameter Dp = 1.3 ft

Structure Information - Floating Debris Weight Wdeb = 6000 lbs

Sheet No: 3 of 8

Objective: Inputs for structure specifications to be used in subsequent large wood stability calculations.

Reference(s):

USBR (U.S. Bureau of Reclamation) & USACE (U.S. Army Corps of Engineers). 2016. National Large Wood Manual - Assessment, Planning, Design, and Maintenance of Large Wood in Fluvial Ecosystems: Restoring Process, Function, and Structure.

USBR. 2014. Large Woody Material - Risk Based Design Guidelines. Reclamation, Managing Water in the West. Pacific Northwest Region Resource & Technical Services.

Project: Repair Storm Damage at Mora Road (95% Design) Project No: 194-1343-0002

Subject: Large Wood Stability Calculations - Deflectors Date: 2/7/2025

Property

Total Volume of Wood

Total Effective Weight

Property

Weight Per Boulder Total Effective Weight

Depth of Soil Backfill Submerged

Average Rootwad Length

Total Volume Volume Per Member

Net Buoyancy Force

Proportion of Voids in Rootwad Tree Stem Average Diameter

Tree Stem Average Length

Property

Wood Type

Number of Logs with Rootwads Specific Gravity of Wood

Average Rootwad Fan Diameter

Design scenario 100-year

Water Depth on Structure Water Depth on Upstream Face of Wood Structure Yu = 23 feet

Water Depth on Downstream Face of Wood Structure Yd = 23 feet

Velocity Approach Velocity Uo = 9 ft/s

Channel Velocity Vc = 9 ft/s Contracted Section Velocity Uc = 9 ft/s

Submerged Structure Area Perpendicular to Flow Upstream Downstream

Width w = 80 80 feet Depth Y = 23 23 feet

Cross-Sectional Area A = 1840 1840 ft2

Other Distance Above Scoured Bed Applied Load hload= 20 feet

Length from tip to point of rotation (1) Lsp = 80 feet Mean distance of piles to point of rotation (2) Lph = 20 feet

Length of structure parallel to flow Ls = 90 feet

Upstream depth to point of rotation(3) dubury = 4 feet Downstream depth to point of rotation(4) ddbury = 4 feet

Mean Distance from Piles to Point of Rotation (5) Lpv = 30 feet

Bank Embedment Embedded length of structure (6) Lebp = 12 feet

Mean Depth of submerged soil above embedded logs Dsub = 6 feet Number of logs embedded into bank 5

Mean Depth of dry soil above embedded logs Ddry = 0 feet

Channel Embedment Embedded length of structure (6) Lebp = 80 feet

Mean Depth of submerged soil above embedded logs Dsub = 2 feet Number of logs embedded into channel bed 5

Mean Depth of dry soil above embedded logs Ddry = 0 feet

Notes

(1) Length of wood structure from tip in the river to point of rotation in the bank measured perpendicular to flow

(2) Measured perpendicular to flow

(3) Depth at upstream side of structure from channel bottom to point of rotation measured perpendicular to flow

(4) Depth at downstream side of structure from channel bottom to point of rotation measured perpendicular to flow

(5) Measured parallel to flow

(6) Embedded length of wood structure measured perpendicular to flow

Objective: 2D hydraulic modeling results inputs for the design scenario to be used in subsequent large wood stability calculations.

Reference(s):

USBR (U.S. Bureau of Reclamation) & USACE (U.S. Army Corps of Engineers). 2016. National Large Wood Manual - Assessment, Planning, Design, and Maintenance of Large Wood in Fluvial Ecosystems: Restoring Process, Function, and Structure.

USBR. 2014. Large Woody Material - Risk Based Design Guidelines. Reclamation, Managing Water in the West. Pacific Northwest Region Resource & Technical Services.

Sheet No:

194-1343-0002

Subject: Large Wood Stability Calculations - Deflectors Date: 2/7/2025

Project: Repair Storm Damage at Mora Road (95% Design) Project No:

Lift:

Assumptions:

Logs and ballast in structure are fully submerged.

Structure acts as composite structure and is assumed to be fully connected.

Structure can move freely vertically without any binding to the piles.

Lift Force:

Area Perpendicular to Flow A = 1,840 ft2

Approach Velocity Uo = 9.0 ft/s Lift Coefficient CL = 1.5

Lift Force FL = 216,617 lb

Buoyancy Force:

Key "Base" Members 51,468 lb

Stacked "Middle" Members 128,671 lb Top Members 0 lb

Total Buoyancy Force FBL = 180,140 lb

Ballast Forces:

Dry wood FLWMd = 0 lb Boulders Fboulders = 0 lb Soil Fsoil = 2,374,853 lb Total Ballast 2,374,853 lb

Factor of Safety Against Buoyancy:

FOSb = 5.99

Reference(s):

USBR (U.S. Bureau of Reclamation) & USACE (U.S. Army Corps of Engineers). 2016. National Large Wood Manual - Assessment, Planning, Design, and Maintenance of Large Wood in Fluvial Ecosystems: Restoring Process, Function, and Structure.

USBR. 2014. Large Woody Material - Risk Based Design Guidelines. Reclamation, Managing Water in the West. Pacific Northwest Region Resource & Technical Services.

Project: Repair Storm Damage at Mora Road (95% Design) Project No: 194-1343-0002

Subject: Large Wood Stability Calculations - Deflectors Date: 2/7/2025

Lift: Normal: Friction:

Drag: Impact:

Calculation Parameters

Bed Sediment Friction Angle 36 degrees Bed Stress μbed= 0.73

Submerged Weight of Ballast Wbl(sub)= 2,374,853 pounds Buoyancy Force Fb = 180,140 pounds

Area Perpendicular to Flow A = 1,840 ft2

Approach Velocity Uo = 9.0 ft/s Drag Coefficient CD = 1.5

Calculation Parameters - Impact Force Weight of debris wdebris = 6000 lbs Channel velocity Vchannel = 9 ft/s

Coefficient of importance Ci = 1 Coefficient of orientation Co = 0.8

Coefficient of depth Cd = 1 Coefficient of blockage Cb = 1

Response ratio for impulsive loads Rmax = 0.8

Acceleration due to gravity g = 32.2 ft/s2

Time from initial velocity to zero velocity 0.03 s

Summary of Forces Force (lbs)

Lift FL= 216,617 Normal Fn= 1,978,096 Friction Ff= 1,437,171 Drag Fd= 216,617 Impact Fi= 56,197

Lateral Resistance Forces - Vertical Pilings and Passive Force

Calculation Parameters Number of Vertical Piles N = 14

Sheet No: 6 of 8

Type

Project: Repair Storm Damage at Mora Road (95% Design) Project No: 194-1343-0002

Subject: Large Wood Stability Calculations - Deflectors Date: 2/7/2025

Objective: Factor of safety calculations for sliding.

Reference(s):

USBR (U.S. Bureau of Reclamation) & USACE (U.S. Army Corps of Engineers). 2016. National Large Wood Manual - Assessment, Planning, Design, and Maintenance of Large Wood in Fluvial Ecosystems: Restoring Process, Function, and USBR. 2014. Large Woody Material - Risk Based Design Guidelines. Reclamation, Managing Water in the West. Pacific Northwest Region Resource & Technical Services.

Length of Pile Below Scoured Bed Lem= 5.0 ft

Distance Above Scoured Bed Applied Load hload= 20.0 ft

Rankine Coefficient of Passive Earth Pressure: Kp = 3.85

Horizontal Restraint Force from Piles:

Fgh(piles) = 13,077 lbs

Passive Force from Embeddment:

Calculation Parameters - Bank Embedment Mean Depth of dry soil above embedded logs Ddry = 0

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