Sediment characterization of the San Luis Pass flood tidal delta Carolina Ramon-Duenas, Julia S. Wellner with Will Sager and others University of Houston ASBPA Texas Chapter 2018 Symposium April 24rd, 2018 August 22, 2017 August 31, 2017 Galveston Bay Entrance during Harvey Side-scan, Bolivar Roads San Luis Pass during Harvey August 31, 2017 San Luis Pass Gulf of Mexico Flood tidal deltas Flood tidal delta - Accumulation of sand on the shoreward side of an inlet Maintained by flood currents FitzGerald et al. 2012 Why San Luis Pass? • One of few natural tidal deltas in Texas • Migrating westward flood delta • San Luis Pass (SLP) tidal delta is the primary sink for most of the sand eroded from updrift parts of Galveston Island Modified Texas General Land Office Methods • 2D High Resolution Seismic (CHIRP) R/V Mishipeshu • Seafloor samples Grain size (CILAS) Smear slides • Publicly available cores and databases 200 um How Chirp is Collected Convert .JSF to .SEGY Extract Navigation using SeiSee Processing (Gain- Smoothing) Load Navigation and SEGY to Kingdom software How Samples are Collected • Water depth • Ripples height • Ripples wavelength • Geometry description • Progradation direction Delta Evolution Evolution SLP flood tidal delta Formation inlet Migration 3-4 m/yr Current position ~2100 yr BP GI – Galveston Island FI – Follets Island Wallace & Anderson 2013 Lateral and vertical lithofacies San Luis Pass Brazos river Davis & Dalrymple 2012 after Israel 1987 Chirp data • 65 km Summer 2017 • 22 km Fall 2017 • 87 km in total Chirp data • 65 km Summer 2017 • 22 km Fall 2017 • 87 km in total A B` A` B Chirp data A A` 12 12 meters Chirp data A A` 12 12 meters Pleistocene-Holocene SB 12 meters Chirp data B B` 9 9 meters Chirp data B B` 9 9 meters Pleistocene-Holocene SB Chirp data B B` Pleistocene- Holocene SB 7.5 meters Pleistocene-Holocene SB Paleo-channel locations -5 m Wallace & Anderson 2013 -20 m River paths from Dellapenna et. al., 2014. Seafloor sediments Seafloor sediment samples • 68 Samples subaqueous ripples (Lee and stoss) • 65 Samples Seafloor • 133 Samples in total Flow direction Seafloor sediment samples Water depth Water Velocity Velocity (m/s) 1 0.8 0.6 0.4 0.2 0 Max spring tide flood ADCIRC model Max spring tide ebb Water Velocity max spring flood ADCIRC model Bedform stability diagram 3D 2D Nichols 1999 Grain size Bedform stability diagram 3D SLP 2D Nichols 1999 Water depth – Ripple height relationship Water depth ripple height 10 y = 0.0426x + 0.7145 R² = 0.5689 1 1 10 100 Ripple (cm) height H 0 Water Depth (cm) h Water depth – Dune height Tidal Dalrymple et.al 2011: Bay of Fundy, Canada/ Macrotidal Water depth= 5*H Reinson 1979: Gulf of St. Lawrence, Canada / Microtidal Water depth= 5*H Rivers Allen 1970: Water depth= 11.6 H0.84 Yalin 1964: Water depth= 6* H Allen 1982 Water depth – Dune height Tidal Dalrymple et.al 2011: Bay of Fundy, Canada/ Data: Macrotidal SLP/ Microtidal Water depth= 5H Water depth= 23.47H+16.77 Reinson 1979: GULF OF ST. LAWRENCE, CANADA / Microtidal Water depth= 5H Rivers Allen 1970: Water depth= 11.6 H0.84 Yalin 1964: Water depth= 6* H Allen 1982 Water depth – Dune height Tidal Dalrymple et.al 2011: Bay of Fundy, Canada/ Data: Macrotidal SLP/ Microtidal Water depth= 5H Water depth= 23.47H+16.77 Reinson 1979: GULF OF ST. LAWRENCE, CANADA / Microtidal Water depth= 5H Rivers Allen 1970: Water depth= 11.6 H0.84 Yalin 1964: Water depth= 6* H Allen 1982 Serendipity Chapter: Pre- and Post- Harvey sediments Hurricane Harvey • Formed: August 17, 2017 • Dissipated: September 3, 2017 • Hit Texas August 25-28, 2017 • It was the first major hurricane to make landfall in the United States since Wilma in 2005 • Hurricane Harvey dumped more than 40 inches of precipitation in some areas of the southeastern Texas and neighboring states. Samples Pre-Harvey Post-Harvey Grain sizes pre- and post- Harvey 8 8 7 7 6 6 Post- 5 41.5Post- 5 37 Harvey Harvey 4 4 23 Lee 33Pre Lee- Pre- (%) Percent Percent (%) Percent 3 Harvey 3 Harvey 23 Stoss 33 Stoss 2 2 1 1 0 0 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 Size (µm) Size (µm) Water Depth (cm) MSL Water Depth (cm) MSL Pre-Harvey -9 Pre-Harvey -9.5 Post-Harvey 74 Post-Harvey 50 Δ 83 Δ 59.5 % Change 922 % Change 626 Why the difference • Grain Size • Erosion from the storm moved sands out offshore • Finer sediments carried by water run off coming from the land • Water Depth • Harvey erosion • Maybe subsidence related to Harvey flexed Earth’s crust Milliner 2017 Coming work • Model sediment transport • Collect more ripples samples http://cirpwiki.info/wiki/CMS April, 2018, EOS back cover. Houston Bayou Sedimentation Allen Parkway, September 2, 2017 "Soil, Sediment, & Silt" Working Group: Sediment Budget through the drainage basin Overwhelming message: • Erosion and sedimentation episodic • Daily processes cannot account for total budget Galveston Bay Anthropogenic Estuary – Toxic Heavy Metals Dr. Jessica Fitzsimmons Harvey lead (Pb) source from Trinity River • Clear heavy metal lead source from Hurricane Harvey from the Trinity River. Not quite toxic levels but >10x normal concentrations at equivalently low salinity. • Lead is a dangerous neurotoxin, with anthropogenic industrial sources. • Where did the lead come from during Harvey? Did it end up in the sediments? On what timescale? How can we prevent this contamination of our backyard waters from happening in a future flood event? Acknowledgements • Funding: UH EAS internal grant award; AAPG Grants-in-Aid 2017; AAPG James E. and Elloie B. Wilson Memorial Grant 2018; NSF RAPID for Harvey response. • Field Work: Carolina Ramon-Duenas, Yuribia Munoz, Li Chang, Jianan Wang, Benjamin Chang, Matthew Sexton, Magdalena Dobrijevic, Delaney Robinson, Rachel Clark, Janet Kong, Raza Mir (UHD), Itzel Cardenas (UHD), Dr. William Sager, Dr. Robert Stewart, Dr. Julia Wellner. Thank You Israel et.al. 1987 Wallace & Anderson 2013 Rice University Coastal Research Group from 1985 to 2003 NOAA station San Luis Pass Chirp surface meters Galveston Pier 21 during Harvey.