crla201801_Hydraulics Memo.pdf

CLEETWOOD TRAIL & MARINA

FINAL WATERWAY DESIGN HYDRAULICS MEMO

To: Carrie Warren, WFLHD Project Manager From: James Neighorn, P.E., WFLHD Hydraulics Engineer Date: Revised May 29, 2024 Project: OR NPS CRLA 2018(1) – Cleetwood Trail and Marina

Background U.S. National Park Service (NPS) is replacing the existing bulkhead located at the end of Cleetwood Cove trail on the Crater Lake shoreline. The existing bulkhead was constructed in 2011 and serves as a trail rest area and a staging area for boat tours. The existing bulkhead was constructed within the wave zone and has experience significant damage due to wave-generated erosion beneath and behind the exterior block wall. During the geotechnical assessment conducted by Golder Associates in 2017, the NPS indicated they do not wish to rebuild the bulkhead within the wave zone along the lake.

Water levels in the lake have been continuously monitored since 1901. The data indicates that the lake level can be subject to abrupt changes, rising or falling over 2 to 3-feet in a single year. The lake level reached a historic high in 1975, reaching an elevation of 6,179.34-feet. Lichen stains on rocks and the presence of existing trees near the shore both indicate that the historical high water level may not have exceeded 6180.50-feet.

A weather station located on the lake (approximately 7,500-feet offshore from the existing bulkhead) has been collecting continuous weather data since 1991. The wind speed data indicates that it is not uncommon for the lake to experience high winds between 36 to 38 MPH each year. The highest recorded wind speed occurred in November of 2001, with a speed of 40.7 MPH with gusts up to 51.8 MPH.

Western Federal Lands Highway Division (WFLHD) is designing the new bulkhead. Recommendations for the initial bulkhead minimum low chord elevation and riprap erosion control are presented.

Recommendations

• Set the new bulkhead above the point of maximum wave runup, elevation 6184.1-feet.

• Project improvements (walls, dock attachments, etc.) that must project below the wave runup zone should be kept above the 10 percent wave, elevation 6182.0-feet.

• Side slopes including or flatter than 2.25(h):1(v) should be protected with Class 5 riprap with a thickness of 38-inches.

• Side slopes 2(h):1(v) and up to 1.5(h):1(v) should be protected with Class 6 riprap with a thickness of 48-inches.

• The limits of Crater Lake are mapped within a Zone A floodplain. Given the minimal improvements along the shoreline, impacts on regulatory floodplain will be negligible. Hydraulic modeling is not anticipated.

Western Federal Lands Highway Division

610 E. Fifth Street Vancouver, WA 98661-3801

Attachments: Figure 1 – Location Map Figure 2 – FEMA FIRM Map Figure 3 – Lake Water Surface Elevations Figure 4 – Weather Station Information Calculations: Wave Height, Runup Height, and Riprap Size

Project Site Location

Map from Google Earth Pro, image date 12/30/2016.

N FIGURE 1

CLEETWOOD MARINA

SITE LOCATION

0 3 miles

Project Site

Weather Station

CRATER LAKE

Rosenburg

Medford

Granite Pass

Approximate Project Location

FEMA FIRM extracted using F-MIT On-Line

FIGURE 2

CLEETWOOD MARINA

FIRM MAP

Data printed from NPS website: https://www.nps.gov/crla/learn/nature/craterlakelevel.htm

N

FIGURE 3

CLEETWOOD MARINA

LAKE WATER SURFACE

ELEVATIONS

maximum windspeed recorded: 40.7 MPH on 11/2001 *adjusted from ~3m to 10m:

Map printed from USGS StreamStats

FIGURE 4

CLEETWOOD MARINA

WEATHER STATION

INFORMATION

Hydraulic Analysis Report

Project Data Project Title: Cleetwood Wave Attack

Designer: James Neighorn

Project Date: October 10, 2023

Project Units: U.S. Customary Units

Notes: Revised calculations from original September 4, 2019, report by Matthew Dillin.

Riprap Analysis: Cleetwood Wave Attack - 2.25:1 Notes:

Input Parameters Riprap Type: Wave Attack

Wave Input Parameters Calculate Wave Parameters

See USACE Coastal Engineering Manual for more information on wind speed, fetch length, and still water depth.

Wind Speed: 60 ft/s

Fetch Length: 25000 ft

Still Water Depth: 4.5 ft

Wave Result Parameters

Wind Velocity Coefficient: 0.0107

Coefficient of Drag: 0.001742

Friction Velocity: 2.50424 ft/s

Dimensionless Fetch Length: 128365

Dimensionless Wave Height: 14.797

10% Wave Height: 3.65992 ft

10% Wave Height = 1.27 * Significant Wave Height

5% Wave Height: 3.97692 ft

5% Wave Height = 1.38 * Significant Wave Height

1% Wave Height: 4.81265 ft

1% Wave Height = 1.67 * Significant Wave Height

Dimensionless Wave Period: 36.4273

Significant Wave Height: 2.88182 ft

This is the lesser of the calculated value or 0.8 * still water depth

Wave Period: 2.833 s

Wave Attack Input Parameters 3

Angle of Slope Inclination: 2.25:1 H:V

Freeboard: 0 ft

Armor Roughness Coefficient: 0.55

Specific Gravity of Riprap: 2.5

A lot of riprap used in coastal areas have specific gravity values less than 2.65, designers should not assume specific gravity equal to 2.65

Specific Gravity of Water: 1

Fresh water = 1.0, sea water = 1.03

Hudson Method is Selected

Design Wave Height: 3.66 ft

Minimum value is the Ten Percent Wave

Empirical Riprap Coefficient: 2.2

Result Parameters Unit Weight of Riprap: 156 lb/ft^3

Weight of Median Riprap Particle Size: 457.814 lb

Dimensionless Breaker Parameter: 1.66883

0-0.5: Spilling wave, 0.5-2.5: Plunging wave, 2.5-3.5: Collapsing Wave, >3.5: Surging wave

Computed D50: 460.677 mm

Riprap Class

Riprap Class Name:CLASS V

Riprap Class Order:5 The following values are an 'average' of the size fraction range for the selected riprap class.

D100: 914.40 mm

D85: 647.70 mm

D50: 469.90 mm

D15: 330.20 mm

Layout Recommendations Wave Runup: 4.23217 ft

Lesser of computed or 1.76*Hs

Vertical Height of Riprap above the Toe of Slope: 12.3922 ft

Thickness of Riprap Protection: 37 ft

No channel used in calculations

Riprap Analysis: Cleetwood Wave Attack - 2:1 Notes:

Input Parameters Riprap Type: Wave Attack

Wave Input Parameters Calculate Wave Parameters

See USACE Coastal Engineering Manual for more information on wind speed, fetch length, and still water depth.

Wind Speed: 60 ft/s

Fetch Length: 25000 ft

Still Water Depth: 4.5 ft

Wave Result Parameters

Wind Velocity Coefficient: 0.0107

Coefficient of Drag: 0.001742

Friction Velocity: 2.50424 ft/s

Dimensionless Fetch Length: 128365

Dimensionless Wave Height: 14.797

10% Wave Height: 3.65992 ft

10% Wave Height = 1.27 * Significant Wave Height

5% Wave Height: 3.97692 ft

5% Wave Height = 1.38 * Significant Wave Height

1% Wave Height: 4.81265 ft

1% Wave Height = 1.67 * Significant Wave Height

Dimensionless Wave Period: 36.4273

Significant Wave Height: 2.88182 ft

This is the lesser of the calculated value or 0.8 * still water depth

Wave Period: 2.833 s

Wave Attack Input Parameters 3

Angle of Slope Inclination: 2:1 H:V

Freeboard: 0 ft

Armor Roughness Coefficient: 0.55

Specific Gravity of Riprap: 2.5

A lot of riprap used in coastal areas have specific gravity values less than 2.65, designers should not assume specific gravity equal to 2.65

Specific Gravity of Water: 1

Fresh water = 1.0, sea water = 1.03

Hudson Method is Selected

Design Wave Height: 3.66 ft

Minimum value is the Ten Percent Wave

Empirical Riprap Coefficient: 2.2

Result Parameters Unit Weight of Riprap: 156 lb/ft^3

Weight of Median Riprap Particle Size: 515.041 lb

Dimensionless Breaker Parameter: 1.87744

0-0.5: Spilling wave, 0.5-2.5: Plunging wave, 2.5-3.5: Collapsing Wave, >3.5: Surging wave

Computed D50: 479.124 mm

Riprap Class

Riprap Class Name:CLASS VI

Riprap Class Order:6 The following values are an 'average' of the size fraction range for the selected riprap class.

D100: 1066.80 mm

D85: 762.00 mm

D50: 546.10 mm

D15: 381.00 mm

Layout Recommendations Wave Runup: 4.76119 ft

Lesser of computed or 1.76*Hs

Vertical Height of Riprap above the Toe of Slope: 12.9212 ft

Thickness of Riprap Protection: 43 ft

No channel used in calculations

Riprap Analysis: Cleetwood Wave Attack - 1.5:1 Notes:

Input Parameters Riprap Type: Wave Attack

Wave Input Parameters Calculate Wave Parameters

See USACE Coastal Engineering Manual for more information on wind speed, fetch length, and still water depth.

Wind Speed: 60 ft/s

Fetch Length: 25000 ft

Still Water Depth: 4.5 ft

Wave Result Parameters

Wind Velocity Coefficient: 0.0107

Coefficient of Drag: 0.001742

Friction Velocity: 2.50424 ft/s

Dimensionless Fetch Length: 128365

Dimensionless Wave Height: 14.797

10% Wave Height: 3.65992 ft

10% Wave Height = 1.27 * Significant Wave Height

5% Wave Height: 3.97692 ft

5% Wave Height = 1.38 * Significant Wave Height

1% Wave Height: 4.81265 ft

1% Wave Height = 1.67 * Significant Wave Height

Dimensionless Wave Period: 36.4273

Significant Wave Height: 2.88182 ft

This is the lesser of the calculated value or 0.8 * still water depth

Wave Period: 2.833 s

Wave Attack Input Parameters 3

Angle of Slope Inclination: 1.5:1 H:V

Freeboard: 0 ft

Armor Roughness Coefficient: 0.55

Specific Gravity of Riprap: 2.5

A lot of riprap used in coastal areas have specific gravity values less than 2.65, designers should not assume specific gravity equal to 2.65

Specific Gravity of Water: 1

Fresh water = 1.0, sea water = 1.03

Hudson Method is Selected

Design Wave Height: 3.66 ft

Minimum value is the Ten Percent Wave

Empirical Riprap Coefficient: 2.2

Result Parameters Unit Weight of Riprap: 156 lb/ft^3

Weight of Median Riprap Particle Size: 686.721 lb

Dimensionless Breaker Parameter: 2.50325

0-0.5: Spilling wave, 0.5-2.5: Plunging wave, 2.5-3.5: Collapsing Wave, >3.5: Surging wave

Computed D50: 527.344 mm

Riprap Class

Riprap Class Name:CLASS VI

Riprap Class Order:6 The following values are an 'average' of the size fraction range for the selected riprap class.

D100: 1066.80 mm

D85: 762.00 mm

D50: 546.10 mm

D15: 381.00 mm

Layout Recommendations Wave Runup: 5.07201 ft

Lesser of computed or 1.76*Hs

Vertical Height of Riprap above the Toe of Slope: 13.232 ft

Thickness of Riprap Protection: 43 ft

No channel used in calculations