Abstract:

The Texas coast is a system of barrier islands, lagoons, estuaries, plains, and rivers on a low-lying coastal plain with gently sloping topography. Embedded in this natural and dynamic system are a variety of human developments and activities including oil and gas production, heavy industry, shipping, commercial fishing, recreational fishing, agriculture, tourism, and small and large communities dotted throughout the landscape. The natural systems of the coastal plain, however, are dynamic and subject to sudden hazards such as floods, storm winds, storm surge, and erosion superimposed on longer-term processes of ongoing erosion caused by sediment supply changes, shifting habitats, sea level rise (SLR), and climate change. Given the vulnerability of the Texas coast, this study assessed the impacts of relative sea level rise (RSLR) and associated enhanced storm surge to better understand the relative susceptibility to negative impacts on the natural and built environments. This study was part of the third publication of the Texas Coastal Resiliency Master Plan (TCRMP) published in April 2023. TCRMP is an ambitious coastal planning effort by the Texas General Land Office (TGLO) to make the Texas coast more resilient to hazards. For this study, the Harte Research Institute (HRI) developed a dynamic modeling framework to assess quantitative information regarding the impacts of SLR and associated enhanced future storm surge caused by higher sea levels and changes in land cover. For the 2023 TCRMP, two SLR scenarios were modeled - Intermediate-Low scenario (0.5 m of SLR by 2100) and Intermediate-High scenario (1.5 meters of SLR by 2100). The relative component of sea level rise was determined on a regional basis by deriving an average trend from long-term records of coastal tide gauges. Similarly, nineteen synthetic storms, ranging in severity from Category 1 to 3, making landfall near major bay systems or city centers across the Texas coast, were modeled for both the current and 2100 landscapes. The coupled hydrodynamic storm surge model, Advanced CIRCulation (ADCIRC) and Simulating Waves in the Nearshore (SWAN) was used to identify the threat posed by storm surge and nearshore waves to communities and the coastal ecosystem in both the current and 2100 landscapes. To better understand the relative vulnerability to storm surge from the full variety of modeled storms, a storm surge vulnerability map was developed by considering all modeled storms in the present and future landscape scenarios. The result of this modeling served as input for geohazards maps that show current and future exposure to changing environmental dynamics in an area. The geohazards maps were essentially a synthesis of all the modeling work done for this study in one product, providing a detailed representation of the present and future state of the coastal plain, highlighting areas that are most susceptible to hazards, and identifying critical coastal environments to preserve or avoid. This dataset contains geohazards maps with two SLR scenarios modeled for four coastal planning regions covering the Texas coast.

Suggested Citation:

Subedee, Mukesh, Lihong Su, Pu Huang, Jessica Magolan, and James Gibeaut. 2023. Geohazards map of the Texas coast under two projected sea level rise scenarios. Distributed by: Gulf of Mexico Research Initiative Information and Data Cooperative (GRIIDC), Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/v1hwhhf5

Purpose:

The Coastal and Marine Geospatial Lab (CMGL) of the Harte Research Institute developed geohazards maps to show areas of the Texas coast that vary in their relative susceptibility to, and function for, mitigating the effects of geohazards both today and into the future as conditions change.

Data Parameters and Units:

Elevations are in meters relative to the NAVD88 datum. Each Geohazards maps show six categories based on the level of hazard potential - 1: Extreme; 2: Imminent; 3: Future Flooding; 4: High; 5: Moderate; 6: Low

Methods:

The geohazards map was developed with a detailed mapping of the different geo-environments currently present on the Texas coastal plain as well as modeling the future evolution of critical coastal environments along the Texas coast. It also incorporates the impacts of both present storm surge and enhanced storm surge caused by higher sea levels and changes in land cover in the future along the coastal plain. Several map-based inputs resulting in a comprehensive geo-environment spatial inventory were used to create the geohazards map that shows the relative susceptibility to negative impacts on the natural and built environments along the coast.

Provenance and Historical References:

Sohl, T.L., Sayler, K.L., Bouchard, M.A., Reker, R.R., Friesz, A.M., Bennett, S.L., Sleeter, B.M., Sleeter, R.R., Wilson, T., Soulard, C. and Knuppe, M., 2014. Spatially explicit modeling of 1992–2100 land cover and forest stand age for the conterminous United States. Ecological Applications, 24(5), pp.1015-1036. https://doi.org/10.1890/13-1245.1 Subedee, M., M. Swift, L. Su, P. Huang, J. Magolan and J. Gibeaut. 2023. Integrated Modeling and Mapping for Coastal Resiliency: Informing the 2023 Texas Coastal Resiliency Master Plan (TCRMP). Final technical report to the Texas General Land Office, Contract Number 21-060-022-C817. Harte Research Institute, Corpus Christi, Texas, USA, 169 pp. https://www.glo.texas.gov/coast/coastal-management/coastal-resiliency/resources/files/2023-tcrmp-overview.pdf Subedee, Mukesh, Claire Pollard, Marissa Dotson, Brach Lupher, Lihong Su, and James Gibeaut. 2019. Sea Level Rise and Storm Surge Modeling in support of the 2019 Texas Coastal Resiliency Master Plan (TCRMP). http://dx.doi.org/10.13140/RG.2.2.19108.04481

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