Trends, Surprises and Pre-Dredge Status at Packery Channel - - PowerPoint PPT Presentation

▶
trends surprises and pre dredge
SMART_READER_LITE
LIVE PREVIEW

Trends, Surprises and Pre-Dredge Status at Packery Channel - - PowerPoint PPT Presentation

May 09, 2023 109 likes •735 views

Trends, Surprises and Pre-Dredge Status at Packery Channel Presented to: Surfrider Foundation Texas Coastal Bend Chapter January 30, 2012 Deidre D. Williams Coastal Research Scientist Conrad Blucher Institute for Surveying and Science Texas

slide-1
SLIDE 1

Trends, Surprises and Pre-Dredge Status at Packery Channel

Presented to: Surfrider Foundation Texas Coastal Bend Chapter

January 30, 2012 Deidre D. Williams

Coastal Research Scientist

Conrad Blucher Institute for Surveying and Science Texas A&M University - Corpus Christi

Program Sponsored by: The City of Corpus Christi Contributing Historic Sponsors: U.S. Army Corps of Engineers District-Galveston Engineering Research and Development Center Coastal Inlets Research Program

slide-2
SLIDE 2

Monitoring at Packery Channel Highlights

  • Brief History
  • Changes Leading up to Dredge
  • Nearshore Morphology

(North Packery)

  • Discussion
  • 17 May 2012 Photo: Courtesy of Dr. Richard Watson
slide-3
SLIDE 3

Packery Channel: A Brief History

Mustang Island North Padre Island Gulf

  • f Mexico

2003 Emily Opens Channel July 2005 Channel Remains Opens July 2006 Dredging Begins Dec 2011

slide-4
SLIDE 4

Cool = Scour/Deeper Region Warm = Shoal

Peak Basin Shoal Shoal Remains Transient Shoaling Persistent Scour

Bathymetry and Morphology 101

Bathymetry = Depth Measurements Morphology = landforms (sand bars, scour, shoals)

Sand bar Deeper Offshore Shallow Nearshore

Deep Shallow

slide-5
SLIDE 5

Well Established Seasonality Aug 2006 to Sep 2008 (Pre-Ike)

slide-6
SLIDE 6

December 2007

Winter Trend

  • Channel Scour
  • Bar builds North
  • Scour increases at

North Jetty

p

  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 9
  • 9
  • 8
  • 8
  • 7
  • 7
  • 6
  • 6
  • 5
  • 5
  • 4
  • 4
  • 3
  • 3
  • 2
  • 2
  • 1

Elevati

  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1

p

30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Legend Depth, ft (MSL)

Scour Sand Bar

slide-7
SLIDE 7

7

June 2008

Summer Trend

  • Channel Shoals
  • Bar builds South
  • Scour increases at

South Jetty

p

  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 9
  • 9
  • 8
  • 8
  • 7
  • 7
  • 6
  • 6
  • 5
  • 5
  • 4
  • 4
  • 3
  • 3
  • 2
  • 2
  • 1

Elevati

  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1

p

30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Legend Depth, ft (MSL)

Scour Sand Bar

slide-8
SLIDE 8

8

Post-Ike Change in System Dynamic Led to Dredge Event Post-Ike June 2009 to Sep 2011

slide-9
SLIDE 9

9

500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000

  • 24
  • 22
  • 20
  • 18
  • 16
  • 14
  • 12
  • 10
  • 8
  • 6
  • 4
  • 2

Depth, ft (MSL) Distance from Deposition Basin, ft

Jetty Entrance Channel

Gulf of Mexico

Inner Channel

MSL

Basin Dune Line

Packery Channel Centerline Pre-Ike, Post-Ike and Limited Recovery

Legend 05 Sep 08 Pre-Ike 23 Sep 08 Post-Ike 06 Jan 09

slide-10
SLIDE 10

Lobe of Sand Forms at Channel Mouth June 2009

Basin/Entrance Shoal expands Lobe

  • f Sand

Forms Shoal Basin Shoal Dominant Seasonal Direction of Longshore Current Lobe

  • f Sand

Forms Shoal

slide-11
SLIDE 11

Basin Shoal Stable Dominant Seasonal Direction of Longshore Current Lobe

  • f Sand

Expands Shoal

Lobe of Sand Expands into Nearshore Sep 2009

Nearly continous flow of sand out of mouth

slide-12
SLIDE 12

Scour Resumes North Lobe of sand reforms toward south Basin Shoal Expands Shoal

Shoals expand from Basin to Channel Mouth January 2010

Winter fronts reinforce current and flush entrance channel

slide-13
SLIDE 13

Basin Shoal Expands Dominant Seasonal Direction of Longshore Current Shoal Lobe

  • f sand

forms Scour Resumes South

Shoals expand from Basin to Channel Mouth June 2010

Lobe of sand forms north side of North Jetty

slide-14
SLIDE 14

Shoals expand from Basin to Channel Mouth September 2010

Navigation depth-limited at channel mouth

Shoal Sustained North Shoal Limits Navigation Scour increases Dominant Seasonal Direction of Longshore Current Basin Shoal Expands

slide-15
SLIDE 15

Shoals expand from Basin to Channel Mouth February 2011

Potential for depth-limited navigation at Basin Shoal

Shoal Migrates into Nearshore Sediment Pathway Remains South Bar Remains Scour Basin Shoal Expands Shoal

Surplus Available Sand in Basin and Immediate Nearshore

slide-16
SLIDE 16

Shoals expand from Basin to Channel Mouth June 2011

Basin Shoal expanding E/W and shoal at mouth > June 2010

Basin Shoal Expands Shoal Reforms in Nearshore Sediment Pathway Well- Developed Bar Migrates Toward Mouth Scour Shoal

slide-17
SLIDE 17

Shoaling Continues in Channel Bypass Bar Builds in Nearshore Sep 2011

Bypass bar Minimal Scour

Basin Shoal Continues to Expand

slide-18
SLIDE 18

Estimated Dredge Volume (August 2007 to September 2011)

slide-19
SLIDE 19

Increase in Sand Volume Inner Entrance and Entrance Channel Aug 2007 to Sep 2011

8/1/2007 5/1/2008 2/1/2009 11/1/2009 8/1/2010 5/1/2011 50000 60000 70000 80000 90000 100000 110000 120000 130000 140000 150000

Volume, cu/yd Date, MDYYYY

14ft

Jun 07 Jun 08 Sep 08 Feb 09 Jun 09 Sep 09 Feb 10 Jun 10 Sep 10 Feb 11 Jun 11 Sep 11

Pre-Ike Post-Ike Winter 08/09 Winter 09/10 Winter 10/11

Sand Volume, cuyd Date, Month YY

Survey Date, Month YY Survey Date, Month YY

1-year post-construction

Base Depth = 14 ft

slide-20
SLIDE 20

8/1/2007 5/1/2008 2/1/2009 11/1/2009 8/1/2010 5/1/2011 20000 30000 40000 50000 60000 70000 80000 90000 100000

14ft A

Jun 07 Jun 08 Sep 08 Feb 09 Jun 09 Sep 09 Feb 10 Jun 10 Sep 10 Feb 11 Jun 11 Sep 11

Date, Month YY Sand Volume, cuyd

Dredge Boat Ramp Winter 02/10 Pre-Ike Post-Ike

Increase in Sand Volume Basin (excluding SW quadrant) Aug 2007 to Sep 2011

1-year post-construction

Survey Date, Month YY Base Depth = 14 ft

slide-21
SLIDE 21

Basin to Mouth Total ≈ 220,000 to 293,000 cu yd of sand (14 to 17 ft dredge depth) Increase > 30,000 cuyd since February 2011

Estimated Sand Volume

slide-22
SLIDE 22

22

Changes in Nearshore Morphology Focus: Bar Development (or lack of!)

slide-23
SLIDE 23

August 2006

Channel Completed

slide-24
SLIDE 24

December 2006

Mid-winter

slide-25
SLIDE 25

February 2007

Peak Winter

slide-26
SLIDE 26

August 2007

Peak Summer

slide-27
SLIDE 27

December 2007

Mid-winter Bar formation (North Side) Influence of Hurricane Humberto?

slide-28
SLIDE 28

June 2008

Peak Spring

slide-29
SLIDE 29

05 September 2008 Pre-Ike

Peak Summer PLUS Influence of Dolly

slide-30
SLIDE 30

23 September 2008 Post-Ike

≈ 20K cu yd Of sand enters channel

slide-31
SLIDE 31

Jan 2010

January 2009

slide-32
SLIDE 32

32

Surplus of Sand…. Contributes to Changes in the Nearshore

slide-33
SLIDE 33

June 2009

Basin/Entrance Shoal expands Lobe

  • f Sand

Forms Shoal Basin Shoal Dominant Seasonal Direction of Longshore Current Lobe

  • f Sand

Forms Shoal

slide-34
SLIDE 34

Basin Shoal Stable Dominant Seasonal Direction of Longshore Current Lobe

  • f Sand

Expands Shoal

Sep 2009

slide-35
SLIDE 35

Scour Resumes North Lobe of sand reforms toward south Basin Shoal Expands Shoal

Shoals expand from Basin to Channel Mouth January 2010

Winter fronts reinforce current and flush entrance channel

slide-36
SLIDE 36

Basin Shoal Expands Dominant Seasonal Direction of Longshore Current Shoal Lobe

  • f sand

forms Scour Resumes South

Shoals expand from Basin to Channel Mouth June 2010

Lobe of sand forms north side of North Jetty

slide-37
SLIDE 37

Shoals expand from Basin to Channel Mouth September 2010

Navigation depth-limited at channel mouth

Shoal Sustained North Shoal Limits Navigation Scour increases Dominant Seasonal Direction of Longshore Current Basin Shoal Expands

slide-38
SLIDE 38

Shoals expand from Basin to Channel Mouth February 2011

Potential for depth-limited navigation at Basin Shoal

Shoal Migrates into Nearshore Sediment Pathway Remains South Bar Remains Scour Basin Shoal Expands Shoal

Surplus Available Sand in Basin and Immediate Nearshore

slide-39
SLIDE 39

Shoals expand from Basin to Channel Mouth June 2011

Basin Shoal expanding E/W and shoal at mouth > June 2010

Basin Shoal Expands Shoal Reforms in Nearshore Sediment Pathway Well- Developed Bar Migrates Toward Mouth Scour Shoal

slide-40
SLIDE 40

Shoaling Continues to Increase in Basin and Entrance Channel Sep 2011

Bypass bar Minimal Scour

Basin Shoal Continues to Expand

slide-41
SLIDE 41

Pre-Dredge Survey Sep 2011

Bypass Bar Develops Longshore Bars Well Developed Peak

  • f Basin Shoal

(3.5 to 4 ft deep) Scour at Mouth Decreases Entrance Shoal Expands and Migrates to West Basin Shoal Expands Peak Shoaling in Entrance Channel

Legend Depth, ft (MSL)

slide-42
SLIDE 42

What is up with the bars at North Packery?

slide-43
SLIDE 43

Development of Nearshore “Shelf” Aug 2007 Location of 8-9 ft (MSL)

Aug 2007 Legend Aerial Oct 2011

slide-44
SLIDE 44

Aug 2007 Sep 2008 Pre-Ike Legend

Development of Nearshore “Shelf” Sep 2008 (Pre-Ike) Location of 8-9 ft (MSL)

Aerial Oct 2011

slide-45
SLIDE 45

Aug 2007 Sep 2008 Post-Ike Legend

Development of Nearshore “Shelf” Sep 2008 (Post-Ike) Location of 8-9 ft (MSL)

Aerial Oct 2011

slide-46
SLIDE 46

Aug 2007 Sep 2009 Legend

Development of Nearshore “Shelf” Sep 2009 Location of 8-9 ft (MSL)

Max Offshore Shift ≈ 150 ft Aerial Oct 2011

slide-47
SLIDE 47

Aug 2007 Sep 2010 Legend

Development of Nearshore “Shelf” Sep 2010 Location of 8-9 ft (MSL)

Max Offshore Shift ≈ 200 ft Aerial Oct 2011

slide-48
SLIDE 48

Aug 2007 Sep 2011 Legend

Development of Nearshore “Shelf” Sep 2011 Location of 8-9 ft (MSL)

Max Offshore Shift ≈ 300 ft Aerial Oct 2011

slide-49
SLIDE 49

Is Erratic Bar Development Related to Shoreline Advance?

slide-50
SLIDE 50

Legend Aug 2003 (Baseline) Jul 2006 Post-Const.)

P P P

Shoreline Position Change

slide-51
SLIDE 51

Legend Aug 2003 (Baseline) Jul 2006 Sep 2007

P P P P

Shoreline Position Change

slide-52
SLIDE 52

Legend Aug 2003 (Baseline) Jul 2006 Sep 2007 Sep 2008 (Post-Ike)

P P P P p

Shoreline Position Change

slide-53
SLIDE 53

Legend Aug 2003 (Baseline) Jul 2006 Sep 2007 Sep 2008 (Post-Ike) Jul 2009

P P P P p sps_

Shoreline Position Change

slide-54
SLIDE 54

Legend Aug 2003 (Baseline) Jul 2006 Sep 2007 Sep 2008 (Post-Ike) Jul 2009 Oct 2010

P P P P p sps_ p

Shoreline Position Change

slide-55
SLIDE 55

Legend Aug 2003 (Baseline) Jul 2006 Sep 2007 Sep 2008 (Post-Ike) Jul 2009 Oct 2010 Nov 2011

P P P P p sps_ p

Shoreline Position Change

slide-56
SLIDE 56

North Packery Shoreline Position Limited Net Change Since Sep 2007

Legend Aug 2003 (Baseline) Sep 2007 (Pre-Ike) Nov 2011

P P P P p sps_ sps_ p

slide-57
SLIDE 57

Beach Profile

slide-58
SLIDE 58

Legend

Profile at North Packery Jetty Sep 2007 to Sep 2011

  • 500

500 1000 1500 2000 2500 3000

  • 20
  • 15
  • 10
  • 5

5 10 15 20

C looks like shift n Sep2008_PostIk Sep2009 Sep2010 Oct2011

Elevation, ft (NAVD88) Distance Across Shore, ft

Sep 2008 Pre-Ike Sep 2008 Post-Ike Sep 2009 Sep 2010 Sep 2011

Legend

slide-59
SLIDE 59
  • 500

500 1000 1500 2000 2500 3000

  • 20
  • 15
  • 10
  • 5

5 10 15 20

Oct2011 K

  • 500

500 1000 1500 2000 2500 3000

  • 20
  • 15
  • 10
  • 5

5 10 15 20

Sep2011 K

Distance Across Shore, ft North Jetty 2000 ft North of Inlet Elevation, ft (NAVD88) Elevation, ft (NAVD88)

slide-60
SLIDE 60
  • 500

500 1000 1500 2000 2500 3000

  • 20
  • 15
  • 10
  • 5

5 10 15 20

B A B

Distance Across Shore, ft

  • 500

500 1000 1500 2000 2500 3000

  • 20
  • 15
  • 10
  • 5

5 10 15 20

Oct2011 K

Elevation, ft (NAVD88) Elevation, ft (NAVD88) North Jetty South end of Seawall

slide-61
SLIDE 61
  • Channel Shoaling occurred gradually over 6 years:

Contributing Factors- wind, drought, Ike

  • Shoal in nearshore

Contributing Factors- surplus sand in Entrance Channel

  • Lack of permanent bars at North Packery
  • Short winter season
  • Strong/persistent longshore current directed from South
  • Expanding nearshore shelf fed by inlet

Summary