Impact of Offshore Directed Forcing on Sediment Transport and Structural Integrity at Packery Channel, Corpus Christi Texas

Transcription

1 Google Earth 29 Aug 2017 Impact of Offshore Directed Forcing on Sediment Transport and Structural Integrity at Packery Channel, Corpus Christi Texas Deidre D. Williams Coastal Research Scientist Conrad Blucher Institute for Surveying and Science Texas A&M University-Corpus Christi Philip Blackmar PE HDR Inc. Philippe Tissot Associate Director, Research Scientist Conrad Blucher Institute for Surveying and Science Texas A&M University-Corpus Christi ASPBA Texas Chapter Symposium Harte Research Institute TAMUCC 24 Apr 2018

2 Packery Channel Location near Confluence of CC Bay and Upper Laguna Madre Aransas Pass Corpus Christi Bay Mustang Island Fish Pass Gulf of Mexico Upper Laguna Madre North Padre Island Newport Pass Packery Channel Bob Hall Pier

3 Packery Channel: A Brief History Sand Emily Plug Facilitates Opens Construction Channel June July 2005 Mustang Island Channel Remains Opens North Padre Island Gulf of Mexico 2003 July 2006 Channel Remains Open Oct st Harvey Dredge 2011/2012 Aug /2013

4 Post-Harvey: Location of Significant Damage Requiring Maintenance and/or Restoration Planning Beach and Backshore Coastal Structures and City Infrastructure

5 Pre-Harvey (July 2017): Regions of Shoaling Upper Laguna Madre Transient Shoal Persistent Shoal Depth, ft (NAVD88) pc_dogleggulf_3ft_navd88opus_march2012_ramp Elevation ft_navd88opus_march2012_ramp Inland Channel Segment (North Reach 2) Packery Channel County Park Inland Channel Segment (South Reach 1) Mollie Beattie Coastal Habitat Community Mustang Island Newport Pass Deposition Basin Lake Padre North Padre Island (NPI) Entrance Channel Packery Channel Google Imagery Jan 2017 NPI Seawall Gulf of Mexico

6 Post-Harvey (Sep 2017): Change in Shoaling and Scour Mollie Beattie Coastal Habitat Community Transient Shoal Persistent Shoal Scour Depth, ft (NAVD88) pc_dogleggulf_3ft_navd88opus_march2012_ramp Elevation AVD88OPUS_March2012_ramp Packery Channel County Park Lake Padre Mollie Beattie Coastal Habitat Community North Padre Island (NPI) Mustang Island Newport Pass Packery Channel Gulf of Mexico Image: CNSA 30 Aug 2017

7 Shoaling and Scour in the Entrance Channel Harvey VS Ike Pre-Harvey Pre-Ike Pre-Ike Post-Harvey Post-Ike Post-Ike Net Sand Volume Decreased by 30,000 cu yd pc_dogleggulf_3ft_navd88opus_march2012_ramp Depth, Elevation ft (NAVD88) VD88OPUS_March2012_ramp Net Sand Volume Increased by 30,000 cu yd

8 Elevation, Jul2017 ft (NAVD88) Elevation, ft (NAVD88) Jul2017 West 5 0 Basin Inner Entrance Channel Entrance Channel East Jul pos -5 Harvey Jul 2017 Pre-Harvey Oct 2017 Post-Harvey Gulf of Mexico Basin Distance Along-Channel from Basin Inner Entrance Channel Jul2017 Entrance Channel Sm sm Ike Gulf of Mexico Jul 2017 Pre-Ike Oct 2017 Post-Ike Distance Along-Channel Jul2017 from Basin

9 Along-Channel Current Velocity, m/s /5/2017 8/10/2017 8/15/2017 8/20/2017 8/25/2017 8/30/2017 9/4/ Flood Water Velocity Water Level Along + Flood - Ebb Water Velocity Water Level Water Level, ft MSL Harvey Water Level, ft MSL Ike Ebb Ike /1/2008 9/6/2008 9/11/2008 9/16/2008 9/21/2008 9/26/ /1/2008 Date (MDY) -4

10 Force Driving Scour and Structural Damage 1.5 m/s Mustang Island NPI Island Packery Channel Velocity m/s Gulf of Mexico 0 m/s Developed by: Larry Dell and Philippe Tissot (CBI TAMUCC)

11 North Padre Island And Mustang Island Mustang Island State Park Fish Pass ² Net Volume Change and Rate of Erosion Mustang Island -454,000 cy -24 cy/ft City Jurisdiction and Multi-Jurisdictional North Padre Island Viento del Mar Padre Balli Park -23,000 cy -14 cy/ft Newport Pass -38,200 cy -17 cy/ft Bob Hall Pier +41, cy/ft -38,200 cy -7 cy/ft +38,000 cy +11 cy/ft -175,000 cy -70 cy/ft City Jurisdiction Net Erosion City Jurisdiction Net Accretion County Jurisdiction Net Erosion County Jurisdiction Net Accretion State Jurisdiction NPI Seawall Limits Gulf of Mexico Scale 1.0 mi/ 1.6 km

12 Shoreline Position Change Aug 2004 Pre-Construction Sep 2007 (Pre-Ike) Aug 2004 Pre-Construction Jul 2017 (Pre-Harvey) Pre-Ike Pre-Harvey

13 Aug 2004 Pre-Construction Sep 2007 (Pre-Ike) Sep 2008 (Post-Ike) Aug 2004 Pre-Construction Jul 2017 (Pre-Harvey) Sep 2017 (Post-Harvey) Post-Ike Post-Harvey

14 Post-Ike Recovery Post-Harvey Partial Recovery Recovery Aug 2004 Pre-Construction Sep 2007 (Pre-Ike) Sep 2008 (Post-Ike) Jul 2009 (10 mo. Post Ike) Post-Ike: Recovery > Erosion North End of Seawall Aug 2004 Pre-Construction Jul 2017 (Pre-Harvey) Sep 2017 (Post-Harvey) Apr 2018 (8 mo. Post Harvey) Post-Harvey: Partial Recovery

15 Rate of Shoreline Position Change: Viento del Mar to Packery NPI Seawall Viento Del Mar Packery Packery Post Harvey: -13 ft/yr Post Ike: -48 ft/yr Post- Ike Post- Harvey

16 Rate of Shoreline Position Change: Mustang Island Packery Newport Fish Pass Post Harvey: -25 ft/yr Post Ike: -62 ft/yr Post- Harvey Post- Ike

17 Structural Assessment: Packery Structural Components Reach 1 SH361 Bridge Boat Ramp Parking Lot 10 ton Granite Blocks Reach 2 1 to 3 ton Riprap Reach 3 Reach 2 Reach 1 Reach 3 Concrete Block Mattresses (ABMs) Reach 4 Unprotected on north side

18 Structural Assessment: Reach 1 Damage Displaced armor stones Indication that some damage occurred during previous storms (Hurricane Ike) Repairs include re-setting the stones

19 Structural Assessment: Reach 1 Original Design Damages to armor stone weaken system for next storm Damage presents increased threat for more significant damage and greater repair cost

20 Packery Structural Components: Reach 2 Reach 2 1 to 3 ton Riprap SH361 Bridge Boat Ramp Parking Lot Reach 3 Reach 2 Reach 1

21 Structural Assessment: Reach 2 Damage Displaced Riprap Damage likely Cumulative of Previous Storm Impacts Existing Damage = System More Prone to Future Damage Repairs Should Place additional riprap to rebuild section

22 Packery Structural Components: Reach 3 SH361 Bridge Boat Ramp Parking Lot Reach 3 Concrete Block Mattresses (ABMs) Reach 3 Reach 2 Reach 1

23 Structural Assessment: Reach 3 Damage Loss of Foundation Material Beneath ABM and Sidewalk Recommended repairs: Removal of ABM, Re-grade Slope, and Replacement of Protection Damage progressively worsen until repaired

24 Structural Assessment: Reach 3 Location of Damaged Segments

25 End Material