In Situ Measurements of Physical Forces, Geotechnical and Biological Parameters in Coastal and Estuarine Systems, Galveston District

Description

Background: The Galveston District has a long history of Civil Works Navigation projects stretching back to the 1880s for River and Harbor improvements, the Gulf Intracoastal Waterway, the Galveston Seawall. The fourth largest city in the nation has sprung up in this region supported by the economic driver that is the local navigation complex. Extending over 50,000 square miles, the Galveston District includes the entirety of the Texas coast, approximately 700 miles. It has over 1,000 miles of channels, of which 270 miles are deep-draft navigation channels. The highest-use navigation channel in the Western Hemisphere is the Houston Ship Channel (HSC) in Galveston Bay. About 30 to 40 million cubic yards are dredged annually in the Galveston District, with an additional 50+ million planned for the expansion of Houston Ship Channel. All reasonable means of placing these sediments beneficially needs to be investigated. Brief Description of Anticipated Work: A new series of dredged material placement areas are proposed to be sited in the vicinity of Atkinson Island and the Mid Bay Placement on the east side of the Houston Ship Channel. There are believed to be historical oyster mining areas throughout the Galveston Bay, in order to determine the extent of these disturbed areas due to these historical mining activities data collection will have to be conducted. This assessment should include the collection of the following geophysical datasets: bathymetry, side scan sonar, and magnetometer data. This data should be used to develop a map of geophysical conditions in 3-D and a model of ongoing “natural” consolidation and develop experimental or theoretical estimates on accelerated consolidation due to various potential overburden or insitu treatments. As an objective of this project we intend to address the following questions:Several questions remain about how to place and confine dredged sediment in a shallow muddy bay system:How can sediments be reliably contained in placement areas using dredged or borrowed sediments?What are the principal forcing factors in dike erosion? Are there “tipping points” in conditions that result in failure?What vegetation is best suited for stabilizing newly constructed dikes?How are mud portions of mostly sandy materials removed during and after beach nourishment? What removal methods work best? How do mud percentages change with dredging methods, time, and varying environmental conditions?This data and research will enable the full-scale implementation of a complementary development and restoration strategy, while focusing research and numerical model development. Research will investigate foundational suitability for new island construction, borrow site suitability, and environmental habitat suitability to support marsh and/or oyster reef. This research will also include an estimation of how surcharge loads or other techniques could incrementally consolidate the depositional material, likelihood of mud waving, is these historical oyster pits enabling containment, capping, and ultimately restoration. Successful applicants should have expert knowledge and work experience with calibration, deployment, data collection, and data reduction from standard underwater sensors. These should include wave gages, current meters, seabed-location sensors, and backscatter (for turbidity and solids computations). Government will not be funding acquisition of sensors. University must already have or be willing to acquire at its own expense these standard sensors. Any unusual sensors required beyond this standard set may be leased or provided at a daily-rate, and the associated cost paid by the Government. The candidates will also be required to submit three (3) quarterly status reports and one (1) annual report each year of the cooperative agreement for updates on the implementation of the project.

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