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Category: Publications: Coastal and Hydraulics Laboratory (CHL)
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  • Geomorphic Metrics Used in FluvialGeomorph

    Abstract: FluvialGeomorph (FG) is a geographic information system-based geomorphic analysis toolkit that analyzes high-resolution terrain data to provide river-reach assessments for watershed studies. This report demonstrates the utility of FG to identify physical stream channel characteristics that are used to determine channel stability. The FG toolbox is a remote-sensing approach based on lidar data, designed to measure channel, floodplain, valley, and watershed metrics necessary for watershed assessments. Currently, channel slope and cross-sectional analysis and planform metrics are being evaluated with existing lidar data from different hydrophysiographic regions within the United States. Recent study areas include the Northwest, Southwest, South, Midwest, and upper Midwest of the United States.
  • Sensitivity of Simulated Flaw-Height Estimates to Phased Array Scan Parameters

    Abstract: Phased array ultrasonic testing (PAUT) is a nondestructive testing (NDT) technique for detecting and sizing flaws in welds. Estimates of flaw size are sensitive to a variety of PAUT scan parameters. In this study, estimates of flaw height are simulated using computer software. The sensitivity of these estimates to selected PAUT scan parameters is analyzed to identify those that have the greatest influence on estimates of flaw height. Understanding how varying different parameters within a phased array instrument affects the accuracy of flaw-height estimates helps to validate PAUT scan procedures and improve flaw-height estimates. For this research, a series of permutations on selected flaws were performed to see how certain parameters affect the accuracy in sizing flaw height. In addition, an analysis on how beam spread leads to flaw sizing inaccuracies was also conducted as part of this work.
  • Evaluation of Structural and Operational Alternatives to Optimize the Distribution of Water and Sediment in the Passes of the Mississippi River

    Abstract: Mississippi River shoaling and dredging processes in the vicinity of Head of Passes and in Southwest Pass were investigated. Existing rates of deposition and dredging were determined using near-daily eHydro bathymetric surveys, National Dredging Quality Management dredge operating data, and geospatial processing steps developed for this study. These surveys provide a means to characterize the highly dynamic and variable sedimentation patterns observed in the navigation channel. The HEC-6T one-dimensional numerical sedimentation model was used to evaluate possible modifications to the distribution of water and sediment in the Mississippi River near Head of Passes in an attempt to reduce shoaling in the navigation channel. The model was used to evaluate the effects of partial closures of several distributaries downstream from Venice and to evaluate the effects of channel widening and channel deepening adjacent to the Hopper Dredge Disposal Area at Head of Passes. In this study, various structural alternatives were compared to a base test that represented existing conditions. Sedimentation and dredging effects were projected 50 years into the future.
  • Acoustic Doppler Current Profiler Study of Water and Sediment Movement through a Deep Scour Hole in the Lower Mississippi River

    Abstract: A series of acoustic Doppler current profiler (ADCP) transects were collected through a deep scour hole at the bend near River Mile 60 on the Lower Mississippi River. The measurements were collected during both a low and a high flow. The ADCP results show a 3D flow field through the deep bend. The backscatter intensity of the ADCP measurements indicates the majority of the sediment remains close to the inside of the bed and high in the water column, with minimal concentrations at the bottom of the bend. These findings have implications for numerical sediment transport models, which tend to deposit material at the bottom of deep scour holes like the one in this study
  • Soil-Moisture Estimation of Root Zone through Vegetation-Index-Based Evapotranspiration-Fraction and Soil-Properties (SERVES) User’s Manual Version 1.0

    Purpose: The purpose of this user’s guide is to provide background methods and implementation guidance on the Soil-moisture Estimation of Root Zone through Vegetation-Index-Based Evapotranspiration-Fraction and Soil-Properties (SERVES) model (Pradhan 2019).
  • Sustainable bank and channel stabilization techniques in arid southwest streams

    Abstract: Channel stabilization and enhancement approaches take many different forms and are implemented using varying construction methods, materials, and techniques. The purpose of this study is to provide a comprehensive evaluation of sustainable streambank stabilization measures that are typically applied in arid southwest (SW) streams. This study was conducted at the request of the US Army Corps of Engineers (USACE), Albuquerque District (SPA), and USACE Headquarters. The document also provides rationale for evaluating bank and bed stabilization measures.
  • Geomorphic Assessment of the St. Francis River: Between Wappapello Lake and Lake City

    Abstract: The St. Francis River is a complex system that lies in the historic floodplain of the Mississippi and Ohio Rivers. The basin has undergone extensive anthropogenic modifications, including reservoir construction, large-scale channelization, and construction of leveed floodways. Several analyses of available gage data, lidar data, and historical research have provided a picture of geomorphic trends and an overall understanding of the river’s stability. The types of analysis used to determine trends included yearly low stage plots, stage-duration curves, specific gage analysis, water surface slopes, and stream power changes. The results from these analyses were synthesized to develop an overall assessment of the reach. Channel cutoffs resulted in a significant decrease in channel length and sinuosity and triggered geomorphic change throughout the river. Immediately following channelization, dramatic decreasing trends in stage were observed for Fisk and Dekyn’s Store, while St. Francis and Holly Island began to aggrade. Slopes and stream power were significantly increased for the upper portion of the study area and showed a decreasing trend for the lower reach.
  • Load and Resistance Factors from Reliability Analysis Probability of Unsatisfactory Performance (PUP) of Flood Mitigation, Batter Pile-Founded T-Walls Given a Target Reliability Index (𝛽)

    Abstract: This technical report documents the research and development (R&D) study in support of the development of a combined Load and Resistance Factor Design (LRFD) methodology that accommodates both geotechnical and structural design limit states for design of the US Army Corps of Engineers (USACE) batter pile-founded, reinforced concrete flood walls. Development of the required reliability and corresponding LRFD procedures has been progressing slowly in the geotechnical topic area as compared to those for structural limit state considerations, and therefore this has been the focus of this first-phase R&D effort. This R&D effort extends reliability procedures developed for other non-USACE structural systems, primarily bridges and buildings, for use in the design of batter pile-founded USACE flood walls. Because the foundation system includes batter piles under flood loading, the design procedure involves frame analysis with significant soil structure interaction. Three example batter pile-founded T-Wall flood structures on three different rivers have been examined considering 10 geotechnical and structural limit states. Numerical procedures have been extended to develop precise multiple limit state Reliability calculations and for complete LRFD analysis of the example batter pile-founded, T-Wall reinforced concrete, flood walls.
  • Antecedent Precipitation Tool (APT) Version 2.0: Technical and User Guide

    Purpose: This document provides an overview of the technical components of the Antecedent Precipitation Tool (APT) and a user’s guide for the APT. The APT is an automation tool that the US Army Corps of Engineers (USACE) developed to facilitate the comparison of antecedent or recent precipitation conditions for a given location to the range of normal precipitation conditions that occurred during the preceding 30 yr*. In addition to providing a standardized methodology to evaluate normal precipitation conditions (precipitation normalcy), the APT queries additional datasets to assess the presence of drought conditions and the approximate dates of the wet and dry seasons for a given location. This document constitutes an update to Antecedent Precipitation Tool (APT) Version 1.0: Technical and User Guide (Gutenson and Deters 2022).
  • Evaluation of a Permeable Dam as an Erosion Control Structure on Coca River, Ecuador

    Abstract: The effort performed here describes the process to evaluate the scour-protection performance of the proposed permeable dam. The US Engineer Research and Development Center, Coastal and Hydraulics Laboratory, built a 1:50 Froude scaled movable bed section model of the permeable dam structure and tested in a specialized flume that simulates regressive erosion propagation. Profiles were collected at various times to track the progression of the scour. Tests evaluated variations of the proposed structure, which included tetrapods, riprap, bridge piers, and longitudinal piles. For the various proposed alternatives, a total of six tests were conducted. The collected profiles show the ability or inability of each alternative and its associated performance. From this analysis, untethered tetrapods could not effectively arrest the local scour around the structure. However, large rock along with invert control stopped the regressive erosion and held the upstream grade.