TWDB to acquire new coastal data to improve flood modeling

TWDB to acquire new coastal data to improve flood modeling Posted on November 14, 2024

To improve the accuracy of coastal flood modeling and other coastal modeling applications, the Texas Water Development Board (TWDB) plans to acquire new bathymetric data along the Texas coast. The latest acquisition in an area between Chambers and Galveston counties will join a growing dataset of bathymetry to fill critical data gaps.

The project was approved at the TWDB's October 17 Board meeting. Data acquired through the project will be used to improve the accuracy of a new three-dimensional coastal model that covers the entire coast of Texas.

Similar to how topography measures the forms and features of land surfaces, bathymetry measures underwater terrain in rivers, lakes, bays, and oceans. The bathymetry dictates the depth of the water, water's velocity, and how it moves, so having a clear picture of the terrain is key for both hindcasting and forecasting efforts as well as planning scenarios. Storm evacuation orders, for example, are based on models that rely heavily on bathymetry data.

"Bathymetry is the most important dataset when it comes to accurate coastal modeling," said Dr. Amin Kiaghadi, Manager of the TWDB's Coastal Science Department. "If the bathymetry is inaccurate or outdated, the models will also be inaccurate."

The acquired data could be used for coastal inundation and hurricane storm simulation, regional flood planning, predicting oil spill trajectory, salinity simulations, coastal resiliency studies, ecological studies, and more. The Texas Geographic Information Office (TxGIO), a division of the TWDB, will procure the data collection services through the Texas Strategic Mapping Program and its associated contracts at the Texas Department of Information Resources. The TWDB's Surface Water Division will oversee the project to ensure the quality of the products.

While coastal bathymetry data already exists for navigation channels on the Texas coast, the TWDB is focusing its acquisition efforts on areas where the data can be improved or updated. In some areas, no data exists or it was collected many decades ago.

The recommendation to acquire new coastal bathymetry data in Texas came from a workshop held by the Texas Integrated Flooding Framework (TIFF) planning project. The participants were TIFF Technical Advisory Team members; academic, state, and federal agencies; industry experts; and data end-users. The participants identified high-priority areas along the coast with an immediate need for bathymetry acquisition based on current data gaps and the age of existing data. So far, data has been collected for the lower San Jacinto River, the Houston Ship Channel, Lower Galveston Bay, Nueces Bay, and the Laguna Madre.

"When we gather high-resolution bathymetry data, it improves the accuracy of coastal modeling, which holds implications for storm surge and coastal inundation modeling," said Caimee Schoenbaechler, Assistant Director of the TWDB's Surface Water Division. "Our goal is to provide accurate data for informed decision-making related to water supply and flood planning." Frequently updating bathymetric data is critical to the accuracy of models because the underwater terrain changes over time. Major storms can disperse sediment from the watershed into the water system, which can significantly change an area's bathymetry.

The TWDB anticipates having the contract in place and collecting data for East Bay and Trinity Bay in 2025. Once finalized, the data will be accessible on the TxGIO Data Hub.

Texas has 367 miles of coastline where 21 river basins terminate, bringing fresh water from surface run-off, rivers, and streams into individual bays. The TWDB Coastal Science program's mission is to advance freshwater inflow science for water resources planning, flood science for coastal resiliency, and emergency oil spill response.

This article is posted in Flood/ Technology/ Water Data.