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.

22 Mar 2023

MODIS Optical Global Water Intelligence (MOGWAI) Web Application User Guide

Abstract: Using the sensor from the Moderate Resolution Imaging Spectroradiometer (MODIS), the MODIS Optical Global WAter Intelligence (MOGWAI) platform is a system created and maintained jointly by the National Geospatial-Intelligence Agency and US Army Corps of Engineers (USACE) that monitors the surface area of lakes and reservoirs using remote sensing in near real time. MOGWAI provides estimates of surface area based on an implementation of the Dynamic Surface Water Extent algorithm that was adapted to use 8-day composites of surface reflectance data from the MODIS sensor, which belongs to the National Aeronautics and Space Administration (NASA). Surface area is monitored for all large waterbodies (greater than 10 km²)* south of 60°N contained in the HydroLAKES database. This information provides near real-time insights related to the regional buffering capacity against flood and drought.

20 Mar 2023

Reception of Automatic Identification System (AIS) Message 21 from US Army Corps of Engineer AIS sites along the Upper Mississippi River, Mile 0 to 301

Purpose: The purpose of this study was to map the on-vessel receipt of message 21 broadcasts from shoreside Automatic Identification System (AIS) sites. Message 21 is one of 27 different AIS messages, and it is used to provide information about real and virtual aids to navigation (AtoNs). Virtual AtoNs are broadcast to warn mariners of hazards like temporary construction zones or submerged debris that may not be marked with a physical buoy. In this study, message 21 was broadcast from different shore-based AIS transceiver sites along the river. Equipment onboard the patrol vessel Pathfinder was monitored for receipt of message 21 during patrols on the Mississippi River that ranged from Lock and Dam (L&D) 22 to Cairo, Illinois, with the confluence of the Ohio River. The Pathfinder is owned by the US Army Corps of Engineers (USACE) and is based out of the St. Louis District (MVS). Understanding where vessels receive, or do not receive, message 21 has important implications for maritime safety in this heavily traveled portion of the inland waterway system.

20 Mar 2023

Hands-Free Mooring for Inland USACE Locks, Phase I: Technical Screening

Purpose: The US Army Corps of Engineers (USACE) Engineer Research and Development Center (ERDC) was asked to evaluate hands-free mooring (HFM) as an option for improving the safety and efficiency of lock operations at USACE locks within the United States. The focus of this research is assessing HFM solutions for barge tows on USACE inland waterway locks. This Coastal and Hydraulics engineering technical note (CHETN) describes the approach and findings from Phase I of this HFM research effort, which was funded through the Navigation Systems Research Program. Phase I includes defining the problem this research effort intends to address, understanding current mooring practices at USACE locks, gathering information on similar systems already in use, and developing design concepts and criteria.