Hurricane Harvey

  • Category 4 hurricane impacted Texas in August 2017
  • Highest winds: 130 mph (215 km/h)
  • Damage: $125 billion (2017 USD)
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Galveston Bay



  • Seventh largest estuary in the US
  • connected to the Metropolitan Huston, highly urbanized
  • Harvey brought a record-breaking precipitation to the Galveston Bay area


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Hurricane Harvey Rainfall for Metropolitan Houston and eastern Texas (https://www.nhc.noaa.gov) (https://www.ncdc.noaa.gov)2



Why Harvey so serious?

  • Harvey was a slow-moving tropical cyclone with the potential to deliver substantially greater volumes of floodwaters.
  • High land subsidence rate due to industrial activities, more susceptible to storm surge.
  • Interactions of several factors (river runoffs & storm surge) induced a more severe and extended compound flooding.
  • A massive load of contaminated sediment delivered to Galveston Bay.









Motivation

  • Harvey deposited 131.34 × 106 tons of sediment, representing 31 years of annual sediment load in the bay, containing at least 5 tons of Hg. 2
  • Develop a numerical model that can represent hydrodynamics during extreme events and apply the model for tracer transport (sediment, mercury).
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The export of the Harvey plume from Galveston Bay. (https://visibleearth.nasa.gov/view.php?id=90866)




Research Goals

  • Modeling the influences of Buffalo Bayou and San Jacinto River on sediment dynamics during Harvey.
  • Estimate sediment flux from San Jacinto Estuary to Galveston Bay.
  • Compare deposition patterns: model vs. sediment core data.

Model Implementation

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Model domain with ~20 m resolution

Time-series of the model input

Notice the time lags among different factors;interactions of Buffalo Bayou, San Jacinto River, and storm surge caused a compound flooding event.


Validation of Hydrodynamics



Model agrees wells with observations in terms of hydrodynamics. The simulation reproduces multiple peaks in water levels (due to different factors) and the extended flooding.

Depth-averaged Suspended Sediment Concentration

Most of the sediments came from the two rivers.

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Sediment flux into upper Galveston Bay

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  • The red transect marks the boundary between San Jacinto Estuary and upper Galveston Bay.

  • The San Jacinto River had a greater impact on sediment transport than Buffalo Bayou during Harvey.

Deposition thickness comparison

There is mismatch between model results and sediment core data.Estimated mass of deposit sediments within San Jacinto Estuary: 2.44× 106 tons (modeled), 7.73× 106 tons (observed).

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Summary

  • Buffalo Bayou and the San Jacinto River delivered a massive load of sediment to Galveston Bay during Hurricane Harvey.
  • The San Jacinto River contributed the most to sediment flux into upper Galveston Bay.
  • A discrepancy in sediment deposition between model simulation and sediment core data.

Future Works

  • Improve sediment deposition calculations: use larger settling velocities of sediment; include prolonged flooding from Buffalo Bayou to represent reservoir drainage.
  • Add a mercury transport module after we are satisfied with the sediment erosion/deposition patterns.

CIV 618 Fall 2023

Reference

  • [1]Dellapenna, T. M., Hoelscher, C., Hill, L., Al Mukaimi, M. E., & Knap, A. (2020). How tropical cyclone flooding caused erosion and dispersal of mercury-contaminated sediment in an urban estuary: The impact of Hurricane Harvey on Buffalo Bayou and the San Jacinto Estuary, Galveston Bay, USA. Science of the Total Environment, 748, 141226.
  • [2]Dellapenna, T. M., Hoelscher, C., Hill, L., Critides, L., Bell, M., Al Mukaimi, M. E., Du, J., Park, K., & Knap, A. H. (2022). Hurricane Harvey Delivered a Massive Load of Mercury-Rich Sediment to Galveston Bay, TX, USA. Estuaries and Coasts, 45(2), 428-444.
  • [3]Du, J., Park, K., Dellapenna, T. M., & Clay, J. M. (2019). Dramatic hydrodynamic and sedimentary responses in Galveston Bay and adjacent inner shelf to Hurricane Harvey. Science of the Total Environment, 653, 554-564.
  • [4]Stearns, A. I., Wellner, J. S., Kendall, J. J., & Khan, S. D. (2023). Sediment routing in an incised valley during Hurricane Harvey (2017) in Houston, Texas, USA: Implications for modern sedimentation. Geology.
  • [5]Valle-Levinson, A., Olabarrieta, M., & Heilman, L. (2020). Compound flooding in Houston-Galveston Bay during Hurricane Harvey. Science of the Total Environment, 747, 141272.
  • [6]Warner, J. C., Armstrong, B., He, R., & Zambon, J. B. (2010). Development of a coupled ocean atmosphere wave sediment transport (COAWST) modeling system. Ocean modelling, 35(3), 230-244.
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