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LU engineers continue riverbank erosion under Sabine Neches Navigation District grant

Lamar University

Lamar University civil engineering professors will soon begin the second phase of a wake wash study in local waterways after receiving $99,000 in additional funding from the Sabine Neches Navigation District.

The researchers will study the relationship between the movement of vessels and the impacts of the waves they generate by their passage on the banks of the region’s waterways.

After completing a study of erosion areas and impacts of passing ships in the first phase under a similar grant from the navigation district, LU Professor Victor Zaloom and faculty colleagues Qin Qian, Mein Jao, Xing Wu, along with Keh-Han Wang, a civil engineering professor with the University of Houston, presented a proposal for a follow-on study to identify effective ways to mitigate the problem.

“In the first phase, we measured the height and speed of waves especially those produced by passing ships. This data allowed us to calculate wave velocity and energy.” Zaloom said. “We obtained ship navigation data including speed and location from the US Coast Guard and correlated ship draft, speed, and other parameters to wave impacts on the riverbank and subsequent erosion.”

In the first phase of the study, Zaloom and Wu surveyed a section of the waterway from the Motiva dock toward the gulf and identified some areas of severe or significant erosion.

“Erosion is a problem for two reasons,” Zaloom said. “It causes loss of land but more important to our sponsor, the Sabine Neches Navigation District, much of the material that results from riverbank erosion ends up in the deep draft ship navigation channel reducing the depth of the channel.”

This material must then be dredged out of the Navigation channel and deposited elsewhere, usually in placement areas, Zaloom said.

Phase II will be devoted to evaluating and recommending wave attenuation remedies that will result in less erosion and reduce the need to dredge the material from the navigation channel.

LU’s researchers will use the Bank Stability and Toe Erosion Model (BSTEM) to investigate possible bank stability alternatives for critical locations along the waterway, and analyze wave attenuation devices for effectiveness against a number of variables, including vessel characteristics, river geometry, and hydrological conditions.

The BSTEM was developed by the U.S. Department of Agriculture and can be used to make informed estimates of erosion. In the LU study, the model will be adapted to incorporate the effects of geotextiles and other bank stabilization measures that affect soil strength with the goal of selecting materials and methods to control waterway bank erosion that are easier on the environment, imitate natural systems, and interact naturally within the ecosystem, and may in turn prove less costly.

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