Evaluation of Surf Zone Conditions For the City of Cape May Hatch - - PowerPoint PPT Presentation

▶
evaluation of surf zone conditions
SMART_READER_LITE
LIVE PREVIEW

Evaluation of Surf Zone Conditions For the City of Cape May Hatch - - PowerPoint PPT Presentation

Aug 26, 2023 340 likes •780 views

Replace entire gray box with one of your presentations images (bleed across the screen). Evaluation of Surf Zone Conditions For the City of Cape May Hatch Mott MacDonald Date 15 December 2015 www.hatchmott.com Evaluation of Surf Zone

slide-1
SLIDE 1

www.hatchmott.com

Replace entire gray box with one of your presentation’s images (bleed across the screen).

Date

Evaluation of Surf Zone Conditions

For the City of Cape May

Hatch Mott MacDonald 15 December 2015

slide-2
SLIDE 2

www.hatchmott.com

  • Outline of presentation:
  • Introduction and Background
  • Wave Assessment
  • Grain Size Evaluation
  • Beach Slope Evaluation
  • Alternatives
  • Numerical Model Results
  • Recommendations
  • Note: The information in this presentation is strictly engineering based,

with no implied or actual health/medical recommendations.

Evaluation of Surf Zone Conditions

slide-3
SLIDE 3

www.hatchmott.com

Cape May, Looking South

Source: USACE

slide-4
SLIDE 4

www.hatchmott.com

Gurney Avenue, Cape May

Source: USACE

slide-5
SLIDE 5

www.hatchmott.com

Philadelphia Avenue, Cape May

Source: USACE

slide-6
SLIDE 6

www.hatchmott.com

Baltimore Avenue, Cape May

Source: USACE

slide-7
SLIDE 7

www.hatchmott.com

 USCG Station – Cape May Inlet Jetty – Buffalo Ave./Yeaton Road  Cape May – Cape May Beach Club – Third Avenue groin

Cape May’s Beaches

slide-8
SLIDE 8

www.hatchmott.com

OLD Design: Federal Project (per Phase II GDM, 1983)

Design Berm Elevation: 8.0 ft NGVD 29

Design Berm Slope: 1V:25H

Design Berm Width: 25 -130 ft.

Nourishment interval: 2 years

CURRENT Design: Federal Project (per USACE FY 09 Monitoring Report)

Design Berm Elevation: 6.7 ft NAVD 88

Design Berm Slope: 1V:10H

Design Beach Width (Design Baseline to MLW (-2.8 ft NAVD 88)): 268 ft.

Nourishment interval: 2 years

Change in Beach Fill Templates

slide-9
SLIDE 9

www.hatchmott.com

Historical Sediment Samples

Sediment Results from McMaster (1954) Sample Number Location Position on Beach Median Grain Size 127 0.17 miles south of harbour jetty, Sewell Pt. Cape May Berm crest 0.130 mm 128 (compare to CRC #108) 0.31 miles north of Wilmington Ave., Cape May 20 ft below berm crest on 6o slope (1V:9.5H) 0.357 mm 129 (compare to CRC #107) 0.28 miles north of Madison Ave., Cape May Beach controlled by

  • seawall. 15 ft from

wall on 3o slope (1V:18H) 0.157 mm 130 Perry Street, Cape May 15 ft below berm crest on 6o slope (1V:9.5H) 0.182 mm

Earliest known publically available data for NJ from the McMaster (1954) report

slide-10
SLIDE 10

www.hatchmott.com

Historical Sediment Samples

Sediment Results from USACE (1983) Sample Number Location Position on Beach Median Grain Size 121 USCG, Sewell Pt. Cape May Berm High tide Mid tide 0.163 mm 0.139 mm 0.187 mm 122 Baltimore Avenue, Cape May Mid tide 0.154 mm 123 Municipal Pier, Cape May High tide Mid tide 0.144 mm 0.132 mm

slide-11
SLIDE 11

www.hatchmott.com

Recent (Oct. 2015) Sediment Samples

2015 Data Collection by Hatch Mott MacDonald Sample Number Location Position on Beach Median Grain Size 108 Cape May Beach Club, Cape May High tide Mid tide Low tide 0.350 mm 0.450 mm 0.410 mm 107 Baltimore Avenue, Cape May High tide Mid tide Low tide 0.370 mm 0.470 mm 0.460 mm 206 South Broadway Ave., Cape May High tide Mid tide Low tide 0.360 mm 0.420 mm 0.430 mm

slide-12
SLIDE 12

www.hatchmott.com

Historical Profile Locations

Howard St. Baltimore Ave.

slide-13
SLIDE 13

www.hatchmott.com

  • 25
  • 20
  • 15
  • 10
  • 5

5 10 15 200 400 600 800

Elevation (ft NAVD88) Distance from Baseline (ft)

USACE Profile CM020 (Near Howard Street)

CM020 1987_03 CM020 2006_09 CM020 2014_09

  • Sep. ‘14

Howard Street Historical Profiles

Data from USACE

Profiles for March 1987 (blue line), September 2006 (red line), and September 2014 (green line) MHW (approx.) MLW (approx.)

  • Mar. ‘87
  • Sep. ‘06
slide-14
SLIDE 14

www.hatchmott.com

  • 25
  • 20
  • 15
  • 10
  • 5

5 10 15 200 400 600 800

Elevation (ft NAVD88) Distance from Baseline (ft)

USACE Profile CM020 (Near Howard Street)

CM020 1987_03 CM020 2006_09

  • 25
  • 20
  • 15
  • 10
  • 5

5 10 15 200 400 600 800

Elevation (ft NAVD88) Distance from Baseline (ft)

USACE Profile CM020 (Near Howard Street)

CM020 1987_03 CM020 2006_09 CM020 2014_09

  • Sep. ‘14
  • Mar. ‘87
  • Sep. ‘06

Howard Street Historical Profiles

Data from USACE

Profiles for March 1987 (blue line), September 2006 (red line), and September 2014 (green line) MHW (approx.) MLW (approx.) 10 ft 10 ft

slide-15
SLIDE 15

www.hatchmott.com

Baltimore Ave. Historical Profiles

Data from Stockton University NJ Beach Profile Network database

Profiles for October 1986 (red dashed line) and August 2006 (black solid line) MHW (approx.) MLW (approx.)

  • Oct. ‘86
  • Aug. ‘06
slide-16
SLIDE 16

www.hatchmott.com

Baltimore Ave. Historical Profiles

Data from Stockton University NJ Beach Profile Network database

Profiles for September 2015 (red dashed line) and October 2015 (black solid line) MHW (approx.) MLW (approx.)

  • Sep. ‘15
  • Oct. ‘15
slide-17
SLIDE 17

www.hatchmott.com

Waves

WIS Station No. 63152 Analysis Results for a 2 ft Wave Parameter Value Average Tm for Hmo = 2 ft 6.6 seconds Average θ for Hmo = 2 ft and Tm = 6.6 ± 0.01 seconds 124º from True North

Cape May City 

USACE Wave Information Studies (WIS) Station 63152 Data

1980 - 2012

(USACE WIS)

slide-18
SLIDE 18

www.hatchmott.com

Howard Street

slide-19
SLIDE 19

www.hatchmott.com

Typical wave beaker types:

– Spilling – Plunging – Collapsing – Surging

Wave Breaker Type

Galvin (1968)

slide-20
SLIDE 20

www.hatchmott.com

Wave breaker type can be determined by the Surf Similarity Parameter/Iribarren number, 𝜊0 :

𝜊0 =

𝑢𝑏𝑜𝛾

𝐼0 𝑀0

(Battjes, 1974)

Where: » 𝑢𝑏𝑜𝛾 = Slope » 𝐼0 = Offshore wave height » 𝑀0 = Deep water wavelength

Wave Breaker Type

Wave breaker type range:

– Collapsing or Surging: 3.3 < 𝜊0 – Plunging: 0.5 < 𝜊0 < 3.3 – Spilling: 𝜊0 < 0.5

slide-21
SLIDE 21

www.hatchmott.com

Wave Breaker Type

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 0.000 0.050 0.100 0.150 0.200 0.250 0.300 0.350

Surf Similarity Parameter Beach Profile Slope (tan β)

Calculated Surf Similarity Parameter Based on Slope

Collapsing or Surging Plunging Spilling

Expected Breaker Type

slide-22
SLIDE 22

www.hatchmott.com

Wave Breaker Type

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 0.000 0.050 0.100 0.150 0.200 0.250 0.300 0.350

Surf Similarity Parameter Beach Profile Slope (tan β)

Calculated Surf Similarity Parameter Based on Slope

Collapsing or Surging Plunging Spilling

Expected Breaker Type Change between spilling and plunging breaker type

  • ccurs at a 1V:21H slope
slide-23
SLIDE 23

www.hatchmott.com

Expected Wave Breaker Types

Profile Slope Surf Similarity Parameter Expected Breaker Type Baltimore Ave. 1986 1V:40.7H 0.26 Spilling Baltimore Ave. 2015 1V:7.6H 1.40 Plunging Hypothetical A 1V:10H 1.06 Plunging Hypothetical B 1V:25H 0.42 Spilling

slide-24
SLIDE 24

www.hatchmott.com

Wave Model Results

Baltimore Ave. 1986 Profile: 1V:40.7H Baltimore Ave. 2015 Profile: 1V:7.6H

slide-25
SLIDE 25

www.hatchmott.com

Turbulent Dissipation (Joules/(kg/s))

Hypothetical Profile: 1V:25H Slope Hypothetical Profile: 1V:10H Slope

Energy dissipation is more rapid in the plunging wave for 1V:10H than 1V:25H

Energy dissipation is confined to a smaller region in the plunging wave for 1V:10H than 1V:25H

slide-26
SLIDE 26

www.hatchmott.com

Alter Beach Slope – Baltimore Avenue

(Initial design investigation)

  • 20
  • 15
  • 10
  • 5

5 10 15 20 100 200 300 400 500 600 700 800

Elevation (ft NAVD88) Distance from Baseline (ft)

Baltimore Ave. Alternative

Alternate Profile with 1V:25H slope 9.17.2015 Stockton Survey Alternate 1V:25H

  • Sep. ‘15
slide-27
SLIDE 27

www.hatchmott.com

Alter Beach Slope – Baltimore Avenue

(Initial design investigation)

  • 20
  • 15
  • 10
  • 5

5 10 15 20 100 200 300 400 500 600 700 800

Elevation (ft NAVD88) Distance from Baseline (ft)

Baltimore Ave. Alternative

Alternate Profile with 1V:25H slope 9.17.2015 Stockton Survey MHW (approx.) MLW (approx.)

  • Sep. ‘15

Alternate 1V:25H

slide-28
SLIDE 28

www.hatchmott.com

Alter Beach Slope – Baltimore Avenue

(Initial design investigation)

  • 20
  • 15
  • 10
  • 5

5 10 15 20 100 200 300 400 500 600 700 800

Elevation (ft NAVD88) Distance from Baseline (ft)

Baltimore Ave. Alternative

Alternate Profile with 1V:25H slope 9.17.2015 Stockton Survey MHW (approx.) MLW (approx.) 10 ft 10 ft

  • Sep. ‘15

Alternate 1V:25H

slide-29
SLIDE 29

www.hatchmott.com

Alter Beach Slope – Howard Street

(Initial design investigation)

  • 30
  • 25
  • 20
  • 15
  • 10
  • 5

5 10 15 100 200 300 400 500 600 700 800 900 1000

Elevation (ft NAVD88) Distance from Baseline (ft)

Howard St. Alternatives

Alternative 1 Alternative 2 USACE CM020 2014_09 Alternative 2 1V:25H Alternative 1 1V:25H Sep ‘14

slide-30
SLIDE 30

www.hatchmott.com

Alter Beach Slope – Howard Street

(Initial design investigation)

  • 30
  • 25
  • 20
  • 15
  • 10
  • 5

5 10 15 100 200 300 400 500 600 700 800 900 1000

Elevation (ft NAVD88) Distance from Baseline (ft)

Howard St. Alternatives

Alternative 1 Alternative 2 USACE CM020 2014_09 MHW (approx.) MLW (approx.) Alternative 2 1V:25H Alternative 1 1V:25H Sep ‘14

slide-31
SLIDE 31

www.hatchmott.com

Alter Beach Slope – Howard Street

(Initial design investigation)

  • 30
  • 25
  • 20
  • 15
  • 10
  • 5

5 10 15 100 200 300 400 500 600 700 800 900 1000

Elevation (ft NAVD88) Distance from Baseline (ft)

Howard St. Alternatives

Alternative 1 Alternative 2 USACE CM020 2014_09 MHW (approx.) MLW (approx.) 15 ft 15 ft Alternative 2 1V:25H Alternative 1 1V:25H Sep ‘14

slide-32
SLIDE 32

www.hatchmott.com

Alter Beach Slope – Initial Quantity Estimates

(Initial design investigation)

 Eastern Section (Yeaton to Philadelphia) – Cut 28.5 cy/l.f. from beach face – Approximately 154,000 cubic yards  Western Section (Philadelphia to Third Ave) – Alternative 1: Cut 21.0 cy/l.f. from beachface – Approximately 168,000 cubic yards – Alternative 2: Cut and fill 120 cy/l.f. – Approximately 816,000 cy of additional sand needed – Extends beyond the end of the groins

slide-33
SLIDE 33

www.hatchmott.com

Groins

Location Inner End El. NAVD Outer End El. NAVD Length Feet Baltimore 7.14 7.14 220 Trenton 7.14 7.14 220 Philadelphia 6.14 4.14 360 Queen 4.14 4.14 572 Gurney 7.14 4.14 425 Jackson 6.84 4.14 650 Grant/Windsor 7.14 4.14 673 Patterson 6.14 4.64 370 Third Ave. 8.14 4.14 786

slide-34
SLIDE 34

www.hatchmott.com

Groins

(Initial design investigation)

Grant Avenue Groin is too high and has a large offset to the neighboring beach

– Reduce elevation to 6.14 ft NAVD 88 and shorten 

Jackson Avenue Groin has a large offset to the neighboring beach  Reduce elevation to 6.14 ft NAVD 88 and shorten

Gurney Avenue Groin is too high, but because it is short, the impact is less

– No change

slide-35
SLIDE 35

www.hatchmott.com

Groins

(Initial design investigation)

Grant Avenue Groin is too high and has a large offset to the neighboring beach

– Reduce elevation to 6.14 ft NAVD 88 and shorten 

Jackson Avenue Groin has a large offset to the neighboring beach  Reduce elevation to 6.14 ft NAVD 88 and shorten

slide-36
SLIDE 36

www.hatchmott.com

 Mechanically alter the foreshore slope  Alter groins – Lower crest height and shorten selected groins  Decrease the grain size of future corps beachfills – Unlikely to have any affect

Project Alternatives

slide-37
SLIDE 37

www.hatchmott.com

Federal (USACE)

– The USACE regulates activities that take place in navigable waters under

Section 10 of the Rivers and Harbors Act of 1899. The United States Army Corps of Engineers (USACE) regulates activities that take place in navigable waters under Section 9 and 10 of the Rivers and Harbors Act of 1899 and waters under Section 404 of the Clean Water Act. This Act prohibits the

  • bstruction or alteration of “waters of the US” without a permit from the Corps
  • f Engineers. Proposed beach grading activities that will take place below the

high tide line will require authorization by a USACE Individual Permit.

– The Cape May beach is an USACE engineered beach therefore beach activities

that may take place in support of the Surf Zone Study will require authorization to alter a USACE Civil Works Project pursuant to 33 USC 408.

Federal and State Permits and Authorizations

slide-38
SLIDE 38

www.hatchmott.com

State (NJDEP)

– Under the NJDEP Coastal Zone Management Rules N.J.A.C. 7:7-2.2, a CAFRA

permit shall be required for any development in the CAFRA area located on a beach or dune.

– Under the NJDEP Coastal Zone Management Rules N.J.A.C. 7:7-2.4, a

Waterfront Development permit shall be required for any activities in any tidal waterway up to and including the mean high water line.

– The City of Cape May currently has a valid Coastal Permit for beach and dune

maintenance activities. Specifically, the bulldozing of sand from the upper beach (berm) to the lower beach (beach face), for the purpose of increasing the berm width or flattening the beach profile, is not considered to be routine maintenance and is not authorized by this permit.

Federal and State Permits and Authorizations

slide-39
SLIDE 39

www.hatchmott.com

City-wide, it is unlikely that the Federal beachfill project has resulted in a steepening of the beach slope in the surf zone

– There is natural variation and information from 1954 that indicates that

approximately 1V:10H in the surf zone may be a natural slope

Sand grain size has become slightly coarser since the beachfills

– Altering the grain size currently on the beach is not a realistic option 

Based on previous USACE attempt to alter the slope (2011), changes will not be permanent

– Therefore, maintaining an unnaturally gentle slope (1V:25H) will likely require

maintenance during the course of the summer months

– Will require permits – Alternative 2 (depicted at Howard Street) which requires additional sand is

unfeasible from a performance perspective

Findings and Recommendations

slide-40
SLIDE 40

www.hatchmott.com

The Recommended Project is:

Pre-summer only, beach slope adjustment from Queen Street to Grant Street

– Sand will be mechanically moved to downdrift sides of groins, into the surf

zone, and into dunes where beneficial to provide a uniform 1V:25H slope to MLW.

– Any excess sand is to be trucked to Wilmington Ave 

Primary project purpose is to alter the wave breaking from plunging to spilling

Secondary project purpose is to provide increased resiliency to dunes in the areas flooded by Sandy

Recommended for further study:

– Altering groins may result in locally gentler slopes (updrift side) and less impact

to shoreline, however this option is very expensive and may result in less beach width between Queen Street and Broadway.

Findings and Recommendations

slide-41
SLIDE 41

www.hatchmott.com

Recommended Plan

Dune width enhancement Cut & fill to achieve 1:25 slope

slide-42
SLIDE 42

www.hatchmott.com

Recommended Plan Cost Estimate

Project Construction Cost Engineering Cost Monitoring Cost Total Cost

Base Project: Queen Street to Grant Street $700,000 $100,000 $50,000 $850,000 Expanded Project: 375’ West of Grant Street and East of Queen Street $900,000 $105,000 $55,000 $1,060,000

slide-43
SLIDE 43

Thank You

For more information, please contact:

Tom Thornton (609) 465-9377 Doug Gaffney Katlin Walling Hatch Mott MacDonald 833 Rt. 9 North Cape May Court House, NJ 08210 www.hatchmott.com

Replace gray box with your own landscape photo (project, people, office scenery etc.).

Hatch Mott MacDonald 3 Paragon Way Freehold, NJ 07728 www.hatchmott.com