scholarly journals Empirical analysis of effects of dike systems on channel morphology and flowlines

2021 ◽  
Author(s):  
Casey Mayne ◽  
David May ◽  
David Biedenharn
Keyword(s):  
Mississippi River ◽  
Channel Morphology ◽  
Army Corps ◽  
Army Corps Of Engineers ◽  
Us Army ◽  
The Us ◽  
River Geomorphology ◽  
Lower Mississippi River ◽  
Insight Into

A phased study of the dike fields within the Vicksburg and Memphis Districts of the US Army Corps of Engineers was conducted to document the channel morphology trends since dike construction on the Lower Mississippi River (LMR). This included the development of the hydrographic survey database and methodology utilized to identify changes in channel geometry in response to dike construction. A subsequent report will provide further refinements to the approach and results of the comprehensive assessment. Recent Mississippi River Geomorphology and Potamology program efforts have employed the database developed by Mr. Steve Cobb to assess the geomorphic changes in 21 dike systems along the LMR. Previous studies using this database have indicated that the dike fields have not caused a loss of channel capacity. Furthermore, these efforts suggested that the trends in the dike fields are closely related to the long-term geomorphic trends along the LMR. Previous efforts using the Cobb database provided considerable insight into the dike effects on the LMR, but they were limited spatially and temporally. In this study, a database and protocols were developed to allow for a more robust assessment of dike field impacts and to extend the spatial and temporal extents of the analysis.

scholarly journals Difficulties Associated with Predicting Depth of Freeze or Thaw

1964 ◽  
Vol 1 (4) ◽  
pp. 215-226 ◽  
Author(s):  
W G Brown
Keyword(s):  
Theoretical Calculations ◽  
Army Corps ◽  
Army Corps Of Engineers ◽  
Corps Of Engineers ◽  
Us Army ◽  
Design Curve ◽  
Theoretical Support ◽  
The Us ◽  
Frost Penetration ◽  
Small Alteration

Calculations using the Neumann solution (as modified by Aldrich) and thermal properties of soils (obtained by Kersten) show that the frost penetration depth for the same freezing index for essentially all soils with any moisture content and for dry sand and rock varies by a factor of about 2 to 1. The extremes calculated in this way bracket the experimentally determined design curve of the US Army Corps of Engineers and give it theoretical support. The theoretical calculations and additional experimental data are used as a basis for a small alteration in the slope of the design curve. This modified design curve is recommended for field use because of (1) inherent imperfections in existing theory and (2) practical limitations to precise specification of field conditions.

Quantifying coastal system resilience for the US Army Corps of Engineers

2015 ◽  
Vol 35 (2) ◽  
pp. 196-208 ◽  
Author(s):  
Julie Dean Rosati ◽  
Katherine Flynn Touzinsky ◽  
W. Jeff Lillycrop
Keyword(s):  
Army Corps ◽  
Army Corps Of Engineers ◽  
Corps Of Engineers ◽  
Coastal System ◽  
Us Army ◽  
The Us ◽  
System Resilience

Assessment of resistance definitions used for blast analysis of unreinforced masonry walls

2017 ◽  
Vol 8 (1) ◽  
pp. 125-151 ◽  
Author(s):  
Eric M Gagnet ◽  
John M Hoemann ◽  
James S Davidson
Keyword(s):  
Unreinforced Masonry ◽  
Degree Of Freedom ◽  
Masonry Walls ◽  
Army Corps ◽  
Army Corps Of Engineers ◽  
Corps Of Engineers ◽  
Single Degree Of Freedom ◽  
Us Army ◽  
Single Degree ◽  
The Us

Over recent decades, three distinct methods have evolved that are currently being used to generate resistance functions for single-degree-of-freedom analyses of unreinforced masonry walls subjected to blast loading. The degree of differences in these resistance definitions depends on whether the wall is assumed to be simply supported or whether compression arching forces result from rotation restraint at the supports. The first method originated in the late 1960s as a result of both experimental and analytical research sponsored by the US Department of Defense. That method, referred to as the Wiehle method, is the basis of Unified Facilities Criteria 3-340-02 and other derived analytical software such as the Wall Analysis Code developed by the US Army Corps of Engineers, Engineer Research and Development Center. The second method is based on elastic mechanics and an assumed linear decay function that follows and is the basis of the widely used Single-Degree-of-Freedom Blast Effects Design Spreadsheets software distributed by the US Army Corps of Engineers, Protective Design Center. The third method is largely based on concrete and masonry behavioral theories developed by Paulay and Priestly in the early 1990s. This article systematically compares the resistance methodologies for arching and non-arching scenarios, demonstrates the implications by plugging the disparate resistance functions into blast load single-degree-of-freedom models, compares the analytical results to full-scale blast test results, and offers conclusions about the accuracy and efficacies of each method.

scholarly journals Initial survey of microplastics in bottom sediments from United States waterways

2021 ◽  
Author(s):  
Justin Wilkins ◽  
Andrew McQueen ◽  
Joshua LeMonte ◽  
Burton Suedel
Keyword(s):  
Bottom Sediments ◽  
Polymer Composition ◽  
Army Corps ◽  
Army Corps Of Engineers ◽  
Us Army ◽  
The Us ◽  
Initial Survey ◽  
Study Sites ◽  
Polymer Type ◽  
Number Of Particles

Given the reported extent of microplastics in the aquatic environment, environmentally relevant exposure information for sediments dredged by the US Army Corps of Engineers will lend context to the risks posed by this contaminant during dredging. We measured the occurrence, abundance, and polymer composition of microplastics in sediments collected from nine dredged waterways and two non-dredged reference areas. The number of particles in sediment samples ranged from 162 to 6110 particles/kg dry wt., with a mean of 1636 particles/kg dry wt. Fragments were the most prevalent shape observed among the 11 study sites (100% frequency of occurrence), followed by fibers (81%), spheres (75%), foams (38%) and films (34%). Based on analyses of chemical composition of the particles using Fourier transform infrared spectroscopy, polyethylene:propylene was the most common polymer type observed. Consistent with results presented by other investigators microplastic concentrations and polymer types in bottom sediments in this study were also aligned with the most widely used plastics worldwide.

scholarly journals Brunswick Harbor numerical model

2021 ◽  
Author(s):  
Jennifer McAlpin ◽  
Jason Lavecchia
Keyword(s):  
Army Corps ◽  
Army Corps Of Engineers ◽  
Engineer Research ◽  
Corps Of Engineers ◽  
Us Army ◽  
Navigation Channel ◽  
The Us ◽  
Model Setup ◽  
Hydraulics Laboratory ◽  
Development Center

The Brunswick area consists of many acres of estuarine and marsh environments. The US Army Corps of Engineers District, Savannah, requested that the US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, develop a validated Adaptive Hydraulics model and assist in using it to perform hydrodynamic modeling of proposed navigation channel modifications. The modeling results are necessary to provide data for ship simulation. The model setup and validation are presented here.

Te Promise of Progress: Modernity, Accumulation, and the Urbanization of North Texas Water in the 20th Century

2018 ◽  
Vol 11 (2) ◽  
pp. 19-34
Author(s):  
James-Eric Simon ◽  
Waquar Ahmed
Keyword(s):  
Army Corps ◽  
Army Corps Of Engineers ◽  
North Texas ◽  
Economic Productivity ◽  
Us Army ◽  
Us Congress ◽  
Government Documents ◽  
The Us ◽  
External Domain ◽  
The City

Rationalities endemic to modernity entail an implicit spatial imaginary of networks. Additionally, modernity envisages nature as an external domain that is discoverable by science and domesticable through technology in order to drive economic productivity. This article examines Grapevine Reservoir as an artifact of modernity. Through an examination of Dallas-based representations of Denton Creek space, we seek to demonstrate that the area was discursively produced as a distal node of the Dallas network: as nothing more than a point-source for urban water. And as water flowed into Dallas, the city flowed outward to Grapevine along the same conduit. We draw on archival data from a major local newspaper during the proposal and construction phases of the reservoir (1921–1954), as well as key government documents prepared by the US Congress and US Army Corps of Engineers (USACE) in the 1940s. Texts were subjected to discourse analysis, to examine how urban interests rationalized Denton Creek space.

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