Houston-Galveston Navigation Channels, Texas Project: Navigation Channel Sedimentation Study, Phase 1

Abstract

The U.S. Army Engineer District, Galveston, has recently enlarged the Houston Ship Channel from a 40-ft (12.2-m) depth by 400-ft (122-m) width to a 45-ft (13.7-m) depth by 530-ft (162-m) width. Previously, a three-dimensional (3-D) numerical model study was implemented at the U.S. Army Engineer Research and Development Center's Coastal and Hydraulics Laboratory to evaluate the salinity and circulation impact of this enlargement. The enlarged channel is nearly complete. Preliminary evaluations indicate a higher than anticipated rate of deposition in the channel reach near Atkinson Island. The purpose of this investigation was to determine if this new shoaling rate was a permanent feature of this new channel or a single anomalous event. If this considerably larger deposition is a permanent condition then the planned disposal locations must be expanded. The project will determine the possible effects on sedimentation in the channel based on dredging records, field data, vessel effects, and hydrodynamic changes due to the channel's enlargement. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.

Houston Ship Channel and vicinity three-dimensional Adaptive Hydraulics (AdH) numerical model calibration/validation report

“…The navigation channel acts as a flow pathway for salinity to travel upstream since high-saline water is heavier than fresh water and tends to flow up-channel along the channel bottom. The net drift in the bottom of the water column is flood in much of the channel (Tate and Berger 2006) (i.e., the tendency is for suspended material to move upstream into the bay). The velocity magnitudes drop in the Atkinson Island reach due to tidal reflections from the bay boundary.…”

“…A reduction in bay salinity results in different suspended concentration patterns and fresh deposit characteristics during this time period compared to data collected at other times during the year. During this period, sediment would tend to collect farther down the channel toward Red Fish Reef (Tate and Berger 2006…”

“…A 3D Adaptive Hydraulics (AdH) model was developed and validated for simulation of hydrodynamics, salinity, and sediment transport. Previous modeling efforts used TABS-MDS as the finite element code (Berger et al 1995;Carrillo et al 2002;Tate and Berger 2006;Tate et al 2008;Tate and Ross 2012). The present effort necessitates the development of a new model utilizing the latest technology and updated to present conditions.…”

“…The boundary conditions for this study are set up in the same manner as the previous work performed for this model domain (Tate et al 2008). Tidal water surface elevations and salinity are applied at the ocean boundary.…”

“…The boundary conditions for the sediment model include grain characteristics, bed definitions, and sediment loads. The conditions established from the previous sediment model validation (Tate et al 2008) were determined from field samples (although a small sample set) in Trinity and Galveston Bays, and these parameters were used as initial parameters for the present AdH/SEDLIB sediment model. This model includes five fine sediment classes (sizes defined by the American Geophysical Union [AGU]), which encompasses the majority of the sediment present in the domain.…”