Headquarters U.S. Army Corps of Engineers News Releases

Long-Term Stability and Efficacy of Historic Activated Carbon (AC) Deployments at Diverse Freshwater and Marine Remediation Sites

Press Operations — Mon, 16 Nov 2020 19:34:00 GMT

Abstract: A number of sites around the United States have used activated carbon (AC) amendments to remedy contaminated sediments. Variation in site-specific characteristics likely influences the long-term fate and efficacy of AC treatment. The long-term effectiveness of an AC amendment to sediment is largely unknown, as the field performance has not been monitored for more than three years. As a consequence, the focus of this research effort was to evaluate AC’s long-term (6–10 yr) performance. These assessments were performed at two pilot-scale demonstration sites, Grasse River, Massena, New York and Canal Creek, Aberdeen Proving Ground (APG), Aberdeen, Maryland, representing two distinct physical environments. Sediment core samples were collected after 6 and 10 years of remedy implementation at APG and Grasse River, respectively. Core samples were collected and sectioned to determine the current vertical distribution and persistence of AC in the field. The concentration profile of polychlorinated biphenyls (PCBs) in sediment pore water with depth was measured using passive sampling. Sediment samples from the untreated and AC-treated zones were also assessed for bioaccumulation in benthic organisms. The data collected enabled comparison of AC distribution, PCB concentrations, and bioaccumulation measured over the short- and long-term (months to years).

Magnetorheological Composite Materials (MRCMs) for Instant and Adaptable Structural Control

Press Operations — Mon, 16 Nov 2020 19:31:00 GMT

Abstract: Magnetic responsive materials can be used in a variety of applications. For structural applications, the ability to create tunable moduli from relatively soft materials with applied electromagnetic stimuli can be advantageous for light-weight protection. This study investigated magnetorheological composite materials involving carbonyl iron particles (CIP) embedded into two different systems. The first material system was a model cementitious system of CIP and kaolinite clay dispersed in mineral oil. The magnetorheological behaviors were investigated by using parallel plates with an attached magnetic accessory to evaluate deformations up to 1 T. The yield stress of these slurries was measured by using rotational and oscillatory experiments and was found to be controllable based on CIP loading and magnetic field strength with yield stresses ranging from 10 to 104 Pa. The second material system utilized a polystyrene-butadiene rubber solvent-cast films with CIP embedded. The flexible matrix can stiffen and become rigid when an external field is applied. For CIP loadings of 8% and 17% vol %, the storage modulus response for each loading stiffened by 22% and 74%, respectively.

Publication Notification: Distribution of the Two-Point Product of Complex Amplitudes in the Fully Saturated Scattering Regime

Press Operations — Mon, 16 Nov 2020 19:28:00 GMT

Abstract: This Letter considers probability density functions (pdfs) involving products of the complex amplitudes observed at two points (which may, in general, involve separations in space, time, or frequency) in conditions of fully saturated scattering. First, the pdf is derived for the product of the complex amplitude at one point with the conjugate of the complex amplitude at another point. It is shown that the real and imaginary parts of this product each have a variance gamma pdf. Second, expressions are derived for several joint pdfs involving complex amplitude products and powers at two points.

Publication Notification: Fort McCoy WWII Buildings and Landscapes

Press Operations — Mon, 16 Nov 2020 19:19:00 GMT

Abstract: The U.S. Congress codified the National Historic Preservation Act of 1966 (NHPA) mostly through the National Register of Historic Places (NRHP), which requires federal agencies to address their cultural resources. Section 110 of the NHPA requires federal agencies to inventory and evaluate their cultural resources, and Section 106 requires them to determine the effect of federal undertakings on those potentially eligible for the NRHP. This report provides a World War II development history and analysis of 786 buildings, and determinations of eligibility for those buildings, on Fort McCoy, Wisconsin. Evaluation of the WWII buildings and landscape concluded that there are too few buildings with integrity to form a cohesive historic district. While the circulation patterns and roads are still intact, the buildings with integrity are scattered throughout the cantonment affecting the historic character of the landscape. Only Building 100 (post headquarters), Building 656 (dental clinic), and Building 550 (fire station) are ELIGIBLE for listing on the NRHP at the national level under Criterion A for their association with World War II temporary building construction (1942-1946) and under Criterion C for their design, construction, and technological innovation.

Red River Structure Physical Model Study

Press Operations — Wed, 14 Oct 2020 12:47:00 GMT

Abstract: A proposed Red River Structure (RRS), intended to function as one of three gated structures comprising the Fargo-Moorhead Metropolitan Area Flood Risk Management Project, was tested in a general physical model. A 1:40 Froude-scale was applied to model the structure, engineered channels, existing bathymetry/topography in the Red River and overbank areas, and the proposed Southern Embankment. The physical model was used to ensure that the RRS could pass at least 104,300 cfs during the Probable Maximum Flood while maintaining a maximum pool water surface elevation of 923.5 ft. The physical model was also utilized to optimize the approach structure, stilling basin, retaining walls, and erosion protection designs. The physical modeling effort resulted in an optimized stilling basin wall, retaining wall, and end sill geometry/configuration where erosive conditions were not observed outside and adjacent to the stilling basin. Properly designed riprap (St. Paul District’s R470 gradation) proved to be successful in protecting the proposed RRS from potential scour downstream. The modified approach wall design proved to be successful in creating safe approach flow conditions as well as acceptable flow separation patterns. It is recommended that Alternative 3 be the design used going forward.

Red River Structure Physical Model Study

Press Operations — Wed, 14 Oct 2020 12:47:00 GMT

The Demonstration and Validation of a Linked Watershed-Riverine Modeling System for DoD Installations – Patuxent Watershed, Maryland

Press Operations — Wed, 14 Oct 2020 12:42:00 GMT

Abstract: This work evaluated a linked watershed and riverine modeling system for the Patuxent River Watershed, Maryland against observed field data and model output from a watershed model. The performance objectives were computed for streamflow, sediment, total phosphorus, orthophosphorus, total nitrogen, ammonium, and nitrate using daily and monthly average model predictions and measured data. Hydrological Simulation Program – Fortran (HSPF) was used to compute runoff, sediment, and nutrient loadings, whereas the Hydrologic Engineer Center – River Analysis Sys-tem (HEC-RAS) was used to evaluate in-stream flow, channel sedimentation, and the fate/transport of nutrients. Model results were successful for calibration, validation, and management scenario analysis. Contaminants were not simulated for this watershed due to a lack of observed data to compare against. The study identified two implementation issues. First, while the Patuxent River did not experience dry bed conditions, where a stream may be intermittent, one can incorporate a very narrow slot at the low point in the cross-section to numerically keep the channel wet during very low flows. Second, to set up the linked model, there needs to be more observed water quality data to better constrain the HSPF output being used as boundary conditions to the HEC-RAS model.

Integrated Rule-Oriented Data System (iRODS) and High Performance Computing (HPC) Project Management Plan

Press Operations — Mon, 21 Sep 2020 16:37:00 GMT

Abstract: This project management plan (PMP) is established to provide guidance on the management of the Integrated Rule-Oriented Data System (iRODS) Project. The PMP and its associated plans are the primary source of information for how the project will be planned, executed, monitored, controlled, and closed. The intended audience of the plan is all project stakeholders including the project manager (PM), Engineered Resilient Systems (ERS), High-Performance Computing (HPC), and the Geocent project team members.

Web-Enabled Interface for iRODS: Comparing Hydroshare and Metalnx

Press Operations — Mon, 21 Sep 2020 16:31:00 GMT

Abstract: The Integrated Rule-Oriented Data System (iRODS) software provides ample resources for managing data and collections thereof, but there are occasions where utilizing its command line interface (CLI) is impractical or not desirable. One such example is when it is required that the user authenticate using a common access card (CAC), which is more easily accomplished through a graphical user interface (GUI) than through a CLI. Furthermore, restricting the system to only offering a CLI can alienate users who would normally be averse to using a system in such a way, and there are users who are not averse to utilizing a CLI, but who would still benefit from a GUI until they are able to familiarize themselves with the iCommands provided by iRODS. Thus, it becomes imperative to either implement or utilize an existing GUI for the system.

Analysis of ERS use cases for iRODs

Press Operations — Mon, 21 Sep 2020 16:26:00 GMT

Abstract: The purpose of this paper is to discuss the challenges inherent with High Performance Computing (HPC) data storage access and management, the capabilities of iRODS, and the analysis of several Engineered Resilient Systems (ERS) use cases relating iRODS capabilities to the teams’ stated needs. Specifically, these teams are the ERS Data Analytics group (specifically their research on rotorcraft maintenance in conjunction with the U. S. Army Aviation and Missile Research Development and Engineering Center [AMRDEC]), the ERS Environmental Simulation research team, the ERS Sensor Systems research team, and the HPC/Scientific computing group representing the “General HPC User.”

PUBLICATION NOTICE: Spatial and Temporal Variance in the Thermal Response of Buried Objects

Press Operations — Thu, 20 Aug 2020 15:26:00 GMT

ABSTRACT: Probability of detection and false alarm rates for current military sensor systems used for detecting buried objects are often unacceptable. One approach to increasing sensor performance and detection reliability is to better understand which physical processes are dominant under certain environmental conditions. Incorporating this understanding into detection algorithms will improve detection performance. Our approach involved studying a small, 3.05 × 3.05 m, test plot at the Engineer Research and Development Center’s Cold Regions Research and Engineering Laboratory (ERDC-CRREL) in Hanover, New Hampshire. There we monitored a number of environmental variables (soil temperature moisture, and chemistry as well as air temperature and humidity, cloud cover, and incoming solar radiation) coupled with thermal infrared and electro-optical image collection. Data collection occurred over 4 months with measurements made at 15 minute intervals. Initial findings show that significant spatial and thermal temporal variability is caused by incoming solar radiation; meteorologically driven surface heat exchange; and subsurface-soil temperatures, density, moisture content, and surface roughness.

PUBLICATION NOTICE: Shallow Water Seakeeping Tests with Columbia Class Submarine for Integration into the Environmental Monitoring and Operator Guidance System

Press Operations — Thu, 20 Aug 2020 15:18:00 GMT

Abstract: The Environmental Monitoring and Operation Guidance System (EMOGS) tool was developed in 1989 to provide a real-time risk analysis for underkeel clearance for the Ohio class submarine while in transit to the Naval Submarine Base at Kings Bay, Georgia. The program computes expected submarine response for input water level, depth, speed, wave, and other input conditions using shallow-water motion transfer functions generated by the strip theory tool, Large Amplitude Motion Program (LAMP). The integration of the new Columbia class submarine into EMOGS required that new transfer functions be developed using LAMP. The LAMP results are to be validated using measured motions from physical model laboratory testing. This report summarizes a laboratory study of the Columbia class submarine response in shallow-water waves. The study was conducted at the US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, and was done in direct support of the Naval Surface Warfare Center, Carderock Division. These seakeeping tests were performed in a shallow basin with a multi-directional wave generator, with measured still water vessel motions and measured vessel motion in regular and irregular waves of varying height, period, and direction.

PUBLICATION NOTICE: Evaluating Collection Parameters for Mobile Lidar Surveys in Vegetated Beach-Dune Settings

Press Operations — Thu, 20 Aug 2020 15:14:00 GMT

Purpose: The goal of this Coastal and Hydraulics Engineering Technical Note (CHETN) is to compare collection parameters and gridding techniques for mobile lidar surveys of beach-dune systems in the northern Outer Banks, NC.

PUBLICATION NOTICE: Utilizing Stream Flows to Forecast Dredging Requirements

Press Operations — Thu, 20 Aug 2020 15:05:00 GMT

Abstract: In recent years, the United States Army Corps of Engineers (USACE) has spent an average of approximately a billion dollars annually for navigation channel maintenance dredging. To execute these funds effectively, USACE districts must determine which navigation channels are most in need of maintenance dredging each year. Traditionally, dredging volume estimates for Operations and Maintenance budget development are based on experiential knowledge and historic averages, with the effects of upstream, precipitation-driven streamflows considered via general-rule approximations. This study uses the Streamflow Prediction Tool, a hydrologic routing model driven by global weather forecast ensembles, and dredging records from the USACE Galveston District to explore relationships between precipitation-driven inland channel flow and subsequent dredged volumes in the downstream coastal channel reaches. Spatially based regression relationships are established between cumulative inland flows and dredged volumes. Results in the test cases of the Houston Ship Channel and the Sabine-Neches Waterway in Texas indicate useful correlations between the computed streamflow volumes and recorded dredged volumes. These relationships are stronger for channel reaches farther inland, upstream of the coastal processes that are not included in the precipitation-driven hydrologic model.

PUBLICATION NOTICE: Three Rivers, Southeast Arkansas Navigation Study: Ship Simulation Report

Press Operations — Thu, 20 Aug 2020 14:55:00 GMT

Abstract: The McClellan-Kerr Arkansas River System (MKARNS) is a major inland waterway that begins at the Port of Catoosa in Tulsa, OK, and travels to the confluence of the White and Mississippi Rivers. Over the years, many structures have been built to help control overland flow between the White, Arkansas, and Mississippi Rivers. These structures have required a significant amount of rehabilitation, which has resulted in high maintenance costs. The US Army Corps of Engineers and the Arkansas Waterways Commission conducted the Three Rivers Southeast Arkansas Feasibility Study (also known as the Three Rivers Study). The Three Rivers Study focused on providing long-term dependable navigation in the MKARNS. From this study, a proposal was developed that included a 1,000 ft reopening of the Historic Cutoff and a reinforcement of several areas near the White River. In 2019, the US Army Engineer Research and Development Center Ship/Tow Simulator was used to perform a navigation study to ensure the proposed modifications did not negatively impact navigation on the White River section of the MKARNS. Assessment of the proposed modifications was accomplished through analysis of ship simulations completed by experienced pilots, discussions, track plots, run sheets, and final pilot surveys.

PUBLICATION NOTICE: A Proposed Ecosystem Services Analysis Framework for the U.S. Army Corps of Engineers

Press Operations — Thu, 20 Aug 2020 14:51:00 GMT

Abstract: Ecosystem goods and services (EGS) have been promoted as a way to effectively examine tradeoffs and improve communication of project-related environmental outcomes in terms of human well-being. This document proposes a framework to inform the development of any future guidance to U.S. Army Corps of Engineers (USACE) District planners for projecting changes in EGS from proposed civil works activities. The framework offers an analytical and communications approach for incorporating EGS in USACE decision-support processes. The core of the framework is a conceptual model that establishes a series of causal relationships that link management actions to EGS benefits/damages, applying economic concepts in both monetary and non-monetary benefit relevant indicators. The six-step planning process is used to demonstrate how the EGS framework might be integrated into existing analytic approaches and modified to fit different levels of resource availability and decision contexts. A hypothetical case study is used to demonstrate analytic techniques. The framework is compatible with goals to create a single decision-support document covering National Environmental Policy Act requirements and planning objectives when comparing project alternatives. The example is intended to generally illustrate the use of EGS in any type of program planning or project evaluation.

PUBLICATION NOTICE: Concept for Artificial Freezing of Sea Ice at Winter Quarters Bay, Antarctica

Press Operations — Thu, 20 Aug 2020 14:44:00 GMT

ABSTRACT: McMurdo Station serves as a major research and logistics hub for the United States Antarctic Program (USAP). Adjacent to the Station is Winter Quarters Bay (WQB), where vessels dock to unload cargo and fuel. The ice pier at McMurdo is essential for this annual vessel resupply but represents a failure potential, occasionally breaking up during or immediately after vessel operations. This study aimed to determine the feasibility of using thermopiles, a passive cooling technology, to artificially freeze seawater to “grow” the existing WQB bottomfast-ice edge so that ships can dock directly against it. Finite element simulations using modeling-parameter assumptions indicate that each row of thermopiles can grow a frozen wall to a depth of 9 m in about a month if installed on 1 July with an initial sea-ice thickness of 1 m and a thermopile spacing of 1.5 m. For our simulation scenarios, we approximate that it would take 255 to 820 days to complete a 40 m by 140 m wedge of bottomfast ice. The estimated cost ranges from about $600,000 to $1,600,000. These results serve as a preliminary feasibility study of successfully using thermopiles for generating a direct docking bottomfast-ice wharf at McMurdo.

PUBLICATION NOTICE: Sediment Sorting by Hopper Dredging and Pump-Out Operations: Sampling Methods and Analysis

Press Operations — Thu, 20 Aug 2020 14:38:00 GMT

Abstract: Hopper dredging operations for beach and nearshore placement typically include periods of overflow, which produces some degree of separation between the size fractions of the dredged sediment. The degree of separation and the controlling factors are presently poorly known. This report focuses on laboratory experiments aimed at determining (1) suitable sampling methods on a dredge, (2) composite sampling techniques to reduce analysis cost, (3) associated sampling intervals to achieve suitable sediment representation of a hopper load, and (4) a hydraulic means of sample splitting. Results showed that no statistical difference exists among the three methods used to sample the hopper weir overflow. The method used to sample deposited hopper sediment identified a bias in the percent fines that resulted from flow sheltering. Further, it was found that composited samples were able to quantify the concentration and percent fines accurately, although an analytical data experiment showed that the accuracy of a composited sample is dependent on the sampling intervals. The accuracy of the fines and concentration from a hydraulic sample splitter was found to be dependent on median grain size, with fine sediment being evenly distributed and coarser sediment increasing the error in concentration and grain size distribution.

PUBLICATION NOTICE: Site-Specific Case Studies for Determining Ground Snow Loads in the United States

Press Operations — Thu, 20 Aug 2020 14:34:00 GMT

ABSTRACT: The U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) has mapped ground snow loads for much of the United States. In some areas where extreme local variations preclude mapping on a national scale, instead of loads, “CS” is used to indicate that Case Studies are needed. This report and the accompanying spreadsheet, which contains the 15,104-station CRREL ground snow load database, provide the information needed to conduct Case Studies. When the latitude, longitude, and elevation of a site of interest are provided, the spreadsheet tabulates data available in the vicinity and generates plots that relate ground snow loads nearby to elevation. With this information, the ground snow load at the site of interest can be determined. This report uses 10 examples to illustrate the methodology and provides our answer and the comments we generate for each of these Case Studies and for 16 additional sites of interest, 8 of which have their answers “disguised” for practice purposes. CRREL has conducted over 1000 Case Studies upon request. Practicing structural engineers were involved in over 250 of them to verify that this methodology is ready to transfer to the design profession.

PUBLICATION NOTICE: Understanding State-of-the-Art Material Classification through Deep Visualization

Press Operations — Thu, 20 Aug 2020 14:30:00 GMT

Abstract: Neural networks (NNs) excel at solving several complex, non-linear problems in the area of supervised learning. A prominent application of these networks is image classification. Numerous improvements over the last few decades have improved the capability of these image classifiers. However, neural networks are still a black-box for solving image classification and other sophisticated tasks. A number of experiments conducted look into exactly how neural networks solve these complex problems. This paper dismantles the neural network solution, incorporating convolution layers, of a specific material classifier. Several techniques are utilized to investigate the solution to this problem. These techniques look at specifically which pixels contribute to the decision made by the NN as well as a look at each neuron’s contribution to the decision. The purpose of this investigation is to understand the decision-making process of the NN and to use this knowledge to suggest improvements to the material classification algorithm.