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

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

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 • •

Packery Channel: A Brief History Emily Opens Channel July 2005 Mustang Island Channel Remains Opens Gulf July 2006 North Padre of Mexico Island Dredging 2003 Begins Dec 2011

Bathymetry and Morphology 101 Bathymetry = Depth Measurements Morphology = landforms (sand bars, scour, shoals) Deep Transient Shoaling Persistent Scour Shoal Peak Remains Sand bar Basin Shoal Shallow Deeper Offshore Shallow Nearshore Cool = Scour/Deeper Region Warm = Shoal

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

Winter Trend December 2007 - Channel Scour Sand Bar - Bar builds North Scour - Scour increases at North Jetty Legend Depth, ft (MSL) Elevati 30 p -1 -2 15 -1 -2 -2 29 -1 14 -1 -2 -1 -2 28 13 -2 -1 -1 -2 27 12 -1 -2 -2 26 -1 11 -1 -2 -1 -2 25 10 -2 -1 -1 -2 24 9 -9 -2 -2 -9 23 8 -8 -2 -8 -2 22 7 -2 -7 -7 -2 21 6 -6 -2 -1 -6 20 5 -5 -1 -5 -1 19 4 -1 -4 -4 -1 18 3 -3 -1 -3 -1 17 2 p -2 -2 16 1 -1

Summer Trend June 2008 - Channel Shoals - Bar builds South Scour - Scour increases at Sand Bar South Jetty Legend Depth, ft (MSL) Elevati 30 p -1 -2 15 -1 -2 -2 29 -1 14 -1 -2 -1 -2 28 13 -2 -1 -1 -2 27 12 -1 -2 -2 26 -1 11 -1 -2 -1 -2 25 10 -2 -1 -1 -2 24 9 -9 -2 -2 -9 23 8 -8 -2 -8 -2 22 7 -2 -7 -7 -2 21 6 -6 -2 -1 -6 20 5 -5 -1 -5 -1 19 4 -1 -4 -4 -1 18 3 -3 -1 -3 -1 17 2 p -2 -2 16 1 -1 7

Post-Ike Change in System Dynamic Led to Dredge Event Post-Ike June 2009 to Sep 2011 8

Packery Channel Centerline Pre-Ike, Post-Ike and Limited Recovery Entrance Channel MSL 0 Jetty Inner Channel -2 -4 Dune -6 Line -8 Gulf of Depth, ft (MSL) Mexico -10 -12 -14 Basin -16 -18 Legend 05 Sep 08 Pre-Ike -20 23 Sep 08 Post-Ike -22 06 Jan 09 -24 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 Distance from Deposition Basin, ft 9

Lobe of Sand Forms at Channel Mouth June 2009 Basin/Entrance Basin Shoal Shoal expands Shoal Shoal Lobe Lobe of Sand of Sand Forms Forms Dominant Seasonal Direction of Longshore Current

Lobe of Sand Expands into Nearshore Sep 2009 Nearly continous flow of sand out of mouth Basin Shoal Stable Shoal Lobe of Sand Expands Dominant Seasonal Direction of Longshore Current

Shoals expand from Basin to Channel Mouth January 2010 Winter fronts reinforce current and flush entrance channel Basin Shoal Expands Scour Shoal Resumes North Lobe of sand reforms toward south

Shoals expand from Basin to Channel Mouth June 2010 Lobe of sand forms north side of North Jetty Basin Shoal Expands Lobe Shoal of sand forms Scour Resumes South Dominant Seasonal Direction of Longshore Current

Shoals expand from Basin to Channel Mouth September 2010 Navigation depth-limited at channel mouth Basin Shoal Expands Shoal Sustained North Shoal Limits Navigation Scour increases Dominant Seasonal Direction of Longshore Current

Shoals expand from Basin to Channel Mouth February 2011 Potential for depth-limited navigation at Basin Shoal Basin Shoal Shoal Expands Migrates into Nearshore Shoal Sediment Pathway Remains Scour South Bar Remains Surplus Available Sand in Basin and Immediate Nearshore

Shoals expand from Basin to Channel Mouth June 2011 Basin Shoal expanding E/W and shoal at mouth > June 2010 Basin Shoal Shoal Expands Reforms in Nearshore Shoal Sediment Pathway Scour Well- Developed Bar Migrates Toward Mouth

Shoaling Continues in Channel Bypass Bar Builds in Nearshore Sep 2011 Basin Shoal Continues to Expand Minimal Scour Bypass bar

Estimated Dredge Volume (August 2007 to September 2011)

Increase in Sand Volume Inner Entrance and Entrance Channel Aug 2007 to Sep 2011 14ft 150000 Base Depth = 14 ft Winter 10/11 140000 130000 Winter 08/09 Winter 09/10 120000 Sand Volume, cuyd Post-Ike Volume, cu/yd 110000 100000 90000 Pre-Ike 80000 70000 1-year 60000 post-construction 50000 Jun 07 Jun 08 Sep 08 Feb 09 Jun 09 Sep 09 Feb 10 Jun 10 Sep 10 Feb 11 Jun 11 Sep 11 8/1/2007 5/1/2008 2/1/2009 11/1/2009 8/1/2010 5/1/2011 Survey Date, Month YY Date, MDYYYY Survey Date, Month YY Date, Month YY

Increase in Sand Volume Basin (excluding SW quadrant) Aug 2007 to Sep 2011 Dredge Boat Ramp 100000 Winter 02/10 Base Depth = 14 ft 90000 80000 Sand Volume, cuyd 70000 60000 14ft Post-Ike 50000 Pre-Ike 40000 30000 1-year post-construction 20000 Jun 07 Jun 08 Sep 08 Feb 09 Jun 09 Sep 09 Feb 10 Jun 10 Sep 10 Feb 11 Jun 11 Sep 11 8/1/2007 5/1/2008 2/1/2009 11/1/2009 8/1/2010 5/1/2011 A Survey Date, Month YY Date, Month YY

Estimated Sand Volume 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

Changes in Nearshore Morphology Focus: Bar Development (or lack of!) 22

August 2006 Channel Completed

December 2006 Mid-winter

February 2007 Peak Winter

August 2007 Peak Summer

December 2007 Bar formation (North Side) Influence of Hurricane Humberto? Mid-winter

June 2008 Peak Spring

05 September 2008 Pre-Ike Peak Summer PLUS Influence of Dolly

23 September 2008 Post-Ike ≈ 20K cu yd Of sand enters channel

January 2009 Jan 2010

Surplus of Sand…. Contributes to Changes in the Nearshore 32

June 2009 Basin/Entrance Basin Shoal Shoal expands Shoal Shoal Lobe Lobe of Sand of Sand Forms Forms Dominant Seasonal Direction of Longshore Current

Sep 2009 Basin Shoal Stable Shoal Lobe of Sand Expands Dominant Seasonal Direction of Longshore Current

Shoals expand from Basin to Channel Mouth January 2010 Winter fronts reinforce current and flush entrance channel Basin Shoal Expands Scour Shoal Resumes North Lobe of sand reforms toward south

Shoals expand from Basin to Channel Mouth June 2010 Lobe of sand forms north side of North Jetty Basin Shoal Expands Lobe Shoal of sand forms Scour Resumes South Dominant Seasonal Direction of Longshore Current

Shoals expand from Basin to Channel Mouth September 2010 Navigation depth-limited at channel mouth Basin Shoal Expands Shoal Sustained North Shoal Limits Navigation Scour increases Dominant Seasonal Direction of Longshore Current

Shoals expand from Basin to Channel Mouth February 2011 Potential for depth-limited navigation at Basin Shoal Basin Shoal Shoal Expands Migrates into Nearshore Shoal Sediment Pathway Remains Scour South Bar Remains Surplus Available Sand in Basin and Immediate Nearshore

Shoals expand from Basin to Channel Mouth June 2011 Basin Shoal expanding E/W and shoal at mouth > June 2010 Basin Shoal Shoal Expands Reforms in Nearshore Shoal Sediment Pathway Scour Well- Developed Bar Migrates Toward Mouth

Shoaling Continues to Increase in Basin and Entrance Channel Sep 2011 Basin Shoal Continues to Expand Minimal Scour Bypass bar

Pre-Dredge Survey Sep 2011 Basin Shoal Expands Entrance Shoal Expands and Migrates to West Scour at Mouth Decreases Peak of Basin Shoal Bypass Bar (3.5 to 4 ft deep) Peak Shoaling in Develops Entrance Channel Legend Depth, ft (MSL) Longshore Bars Well Developed

What is up with the bars at North Packery?

Development of Nearshore “Shelf” Aug 2007 Location of 8-9 ft (MSL) Legend Aug 2007 Aerial Oct 2011

Development of Nearshore “Shelf” Sep 2008 (Pre-Ike) Location of 8-9 ft (MSL) Legend Aug 2007 Sep 2008 Pre-Ike Aerial Oct 2011

Development of Nearshore “Shelf” Sep 2008 (Post-Ike) Location of 8-9 ft (MSL) Legend Aug 2007 Sep 2008 Post-Ike Aerial Oct 2011

Development of Nearshore “Shelf” Sep 2009 Location of 8-9 ft (MSL) Legend Aug 2007 Max Offshore Sep 2009 Shift ≈ 150 ft Aerial Oct 2011

Development of Nearshore “Shelf” Sep 2010 Location of 8-9 ft (MSL) Legend Aug 2007 Max Offshore Sep 2010 Shift ≈ 200 ft Aerial Oct 2011

Development of Nearshore “Shelf” Sep 2011 Location of 8-9 ft (MSL) Legend Aug 2007 Max Offshore Sep 2011 Shift ≈ 300 ft Aerial Oct 2011

Is Erratic Bar Development Related to Shoreline Advance?

Shoreline Position Change Legend Aug 2003 (Baseline) P Jul 2006 Post-Const.) P P