7 Jul 2023

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.

5 Jul 2023

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.

26 Jun 2023

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).

16 Jun 2023

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.

6 Jun 2023

Testing the Compatibility of the Sediment Budget Analysis System 2020 with Various Data Sources

Abstract: This Regional Sediment Management technical note (RSM TN) provides the workflow for implementing results of various toolsets into the Sediment Budget Analysis System (SBAS). SBAS is a commonly used toolset developed by the US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory (ERDC-CHL) for creating and visualizing sediment budgets. Recent upgrades to SBAS have warranted an investigation into its ability to accurately accept various data sources. Three case studies are presented showcasing the variety of acceptable tools, both ERDC-CHL published and custom-user created.

25 May 2023

Mississippi River Climate Model–Based Hydrograph Projections at the Tarbert Landing Location

Abstract: To better understand and prepare for the possible effects associated with potential climate changes on the lower Mississippi River, the State of Louisiana Coastal Protection and Restoration Authority sought information on the historical, current, and projected future hydrodynamics of the Mississippi River. To this end, flow duration curves (FDC) for the Tarbert Landing location were generated, based on climate models derived from two of the four scenarios of the Coupled Model Intercomparison Project, Phase 5 (CMIP5), multimodel ensemble representative concentration pathways (RCPs). The global CMIP5 datasets were used by the variable infiltration capacity land surface model to produce a runoff dataset, using a bias-correction spatial disaggregation approach. The runoff datasets were then applied to simulate streamflow using the Routing Application for Parallel computatIon of Discharge (RAPID) river routing model. Based on the streamflow, FDCs were calculated for 16 CMIP5 as well as observed historical data at the Tarbert Landing location. Key observations from the results are that the 90th percentile exceedance of the simulated versus the observed flows is more frequent for the RCP 8.5 scenario than for the RCP 4.5 scenario and that the maximum annual flows for the RCP 8.5 scenario are generally smaller than for the RCP 4.5 scenario.

25 May 2023

Geomorphic Feature Extraction to Support the Great Lakes Restoration Initiative’s Sediment Budget and Geomorphic Vulnerability Index for Lake Michigan

Purpose: This Coastal and Hydraulics Engineering technical note (CHETN) details a Geographic Information Systems (GIS) methodology to produce advanced lidar-derived datasets for use in a coastal erosion vulnerability analysis conducted by the US Army Corps of Engineers (USACE) and other federal partners for the Great Lakes Restoration Initiative (GLRI).

25 May 2023

Automatic Identification System (AIS) Data Case Study: Identifying Unofficial Mooring Areas along the Upper Mississippi River

Purpose: This Dredging Operations and Technical Support (DOTS) program technical note presents the results of a study undertaken at the request of staff from the US Army Corps of Engineers (USACE) Rock Island District (MVR) as part of a larger effort examining the potential creation of seven new permanent mooring cells along the Upper Mississippi River in proximity to lock and dam (LD) locations selected by MVR. MVR staff were interested in evaluating vessel traffic and identifying unofficial mooring areas (i.e., waiting areas) in the vicinity of LD7, LD10, LD11, LD14, LD15, LD20, and LD22; they were also interested in travel times from those unofficial mooring areas to the destination lock. The search distance for unofficial mooring areas was limited to 20 miles from the lock, or the distance to the next closest lock if less than 20 miles, in the appropriate direction (i.e., upstream or downstream), as specified by MVR staff.

21 Apr 2023

Representative Beach Profile Generator

Abstract: The purpose of this Coastal and Hydraulics Engineering Technical Note (CHETN) is to introduce an Esri ArcGIS Pro ArcPy Toolbox entitled “Representative Beach Profile Generator (RBPG)” that generates a single representative profile for a given study area based on elevation profiles. The toolbox aligns and averages input elevation profiles into a single profile based upon a chosen alignment feature. Furthermore, the toolbox allows the user to create maximum and minimum trapezoidal profile approximations for use within numerical models such as Storm-Induced BEAch CHange (SBEACH) and Beach-fx. This CHETN presents a brief description of the toolbox methods and includes a short demonstration of the toolbox’s application to help familiarize the user with inputs, outputs, and possible uses. The RBPG toolbox is available for public download at the link where this paper is hosted with the US Army Engineer Research and Development Center library services (http://dx.doi.org/10.21079/11681/46916).

18 Apr 2023

Comparing Methods for Estimating Water Surface Elevation between Gages in the Lower Mississippi River

Abstract: Predicting a water surface elevation (WSElev) at a particular location has a wide range of applications like determining if a levee will overtop or how much a dike notch will increase water flow into a secondary channel. Five existing methods for predicting the water’s surface, (1) daily slope, (2) average slope, (3) River Analysis System (RAS) 1D, (4) RAS 2D, and (5) Adaptive Hydraulics modeling system (AdH), were used to predict the Mississippi River’s daily water surface from 10 October 2014 to 31 May 2016 at Friar’s Point, Greenville, and Natchez gages. The error, calculated as the model-predicted water surface minus the gage-observed water surface, was compared among the methods. The average slope method, using Helena and Fair Landing gages, and the daily slope method, using either Memphis and Helena or Helena and Arkansas City gages, most closely estimated the observed WSElev. The RAS 1D predictions for Friar Point and Greenville produced more accurate estimates than the RAS 2D model and were the only estimates that did not show a pattern of over- or underestimation. When the daily slope method was applied to gages that were farther apart (Memphis and Arkansas City, Arkansas City and Vicksburg, or Vicksburg and Knoxville), the error became greater than most RAS 1D and 2D predictions. The low error and simple calculations of the daily slope and average slope methods using gages <110 river miles apart make these methods useful for calculating current and historic conditions. The lack of over- or underestimation in the RAS 1D predictions (for locations away from the edges of the model area) make this method a better choice for predicting average WSElevs and a good choice for forecasting future WSElevs.