6 May 2025

Technical Recommendations for the Identification and Management of Potential Acid Sulfate Soils in an Ecological Restoration Context

Abstract: Restoration projects are being implemented to address natural and anthropogenic threats to coastal wetlands, including increased inundation and historic land use alterations. The US Army Corps of Engineers (USACE) and other organizations introduce dredged sediments into coastal environments to increase elevation and stabilize marsh platforms. However, some dredged sediments either contain iron sulfide compounds (i.e., iron monosulfide [FeS] and pyrite [FeS₂]) or form them after application. Under aerobic conditions, FeS and FeS₂ can rapidly oxidize, which generates acidity that can dramatically lower the soil pH, impacts plant establishment, and threatens the success of wetland restoration projects. Recommendations are needed to properly manage iron sulfide containing materials through project design, screening, monitoring, and adaptive management. Tools and techniques exist to evaluate dredged sediments for the presence of FeS and FeS₂ prior to and following marsh sediment applications, and project design and construction approaches can minimize associated acidification risks. This report provides a framework for properly identifying and managing sediments containing iron sulfide minerals during wetland restoration projects. These technical recommendations provide dredged sediment beneficial use practitioners a decision support tool for the successful management of iron sulfide containing dredged sediments to increase the ecological function and sustainability of coastal wetlands.

6 May 2025

Applications of the CRREL–-Geometric Optics Snow Radiative Transfer (GOSRT) Model: Incorporating Diffraction and Simulating Detection of Buried Targets

Abstract: Radiative transfer through a snow surface within the visible and near infrared (NIR) spectra is complicated by the shape, size, and configuration of the snow grains that comprise the snow surface. Ray-tracing and photon-tracking techniques combined with 3D renderings of snow resolved at the microscale have shown promise as a means to directly simulate radiative transfer through snow with no restrictions on the snow grain configuration. This report describes and evaluates the US Army Cold Regions Research and Engineering Laboratory (CRREL) Geometric Optics Snow Radiative Transfer (GOSRT) model. In particular, we describe the incorporation of the diffraction process into the photon-tracking framework and evaluate how accurately the model simulates the spectral albedo of targets buried within the snow. We find that the model simulated spectral albedo is little affected by the incorporation of diffraction for most applications. However, there are nonnegligible impacts on simulated albedo for small grains in the NIR due to a reduction in forward scattering. We conclude by recommending that diffraction is neglected in CRREL–GOSRT for most cases, as including it substantially increases the computational expense with minimal impacts on the result. Finally, we show that buried targets are only distinguishable for very shallow snowpacks.

5 May 2025

Assessing a Mobile Microgrid to Support Electric Vehicle Charging Stations on Army Installations

Abstract: Supplying reliable, off-grid power is critical for transitioning the Army’s fleet to zero carbon emitting vehicles. At the same time, vehicle charging and mission support equipment may require increased electrical loads than currently experienced at Army installations. Other decarbonization initiatives require clean sources of energy. Using microgrids powered with renewable electricity generation systems is a viable, independent solution for powering electric vehicles. Yet, there is a need to fill information gaps in the performance of these systems for realizing sustainable and resilient energy. The goal of this project was to increase the Army’s energy resilience by reducing reliance on the utility grid by using a compact and mobile microgrid that functions as an EV charging station. In this study, a trailered, mobile microgrid that integrates solar panels, a diesel generator, and batteries is evaluated based on performance under varying conditions. The energy generation capabilities are documented and evaluated for capabilities for powering electric vehicles. The outcomes of this research are the advancement of energy resiliency and the addition of performance in temperate and cold regions to the knowledge base. It is also anticipated this research may be leveraged to facilitate power independence and further support decarbonization efforts.

2 May 2025

Mobile Runway Edge Sheave Anchor Criteria in Asphalt Concrete Pavement

Abstract: The Mobile Runway Edge Sheave (MRES) is used in conjunction with the Mobile Aircraft Arresting System (MAAS) for setback aircraft arresting system (AAS) installations in expedient or temporary situations. There are existing criteria and tactics, techniques, and procedures (TTPs) for MRES installations on portland cement concrete (PCC) pavement and soil, but these criteria have not been developed for asphalt concrete (AC) pavements. The US Air Force Civil Engineer Center (AFCEC) tasked the US Army Engineer Research and Development Center (ERDC) to develop anchor criteria for the MRES in AC pavement and to perform full-scale load testing on the MRES to evaluate system response under representative loads. Three anchor stake layouts were evaluated under static and cyclic loading conditions: a 32-stake layout, a 16-stake layout, and an 8-stake layout. Elastic-plastic deflection data from the three test series were comparatively analyzed and show that the performance of the 16-stake layout was similar to that of the 32-stake layout for the given loading condition and pavement structure.

1 May 2025

Resilience: Directions for an Uncertain Future Following the COVID-19 Pandemic

Abstract: The concept of resilience is multi-faceted. This commentary builds upon the analytical distinctions of resilience provided by Urquiza et al. (2021, https://doi.org/10.1029/2020EF001508). In response to this article, we emphasize several distinctions between resilience and other systems concepts. These include distinctions between resilience, risk, and vulnerability, the tradeoff between resilience and efficiency, resilience contrasted with robustness, the relationship between resilience and sustainability, and finally methods for building resilience-by-design or resilience-by-intervention. Improving understanding of these concepts will enable planners to select resilience strategies that best support their system goals. We use examples from the 2020–2021 coronavirus pandemic to illustrate the concepts and the juxtapositions between them.

1 May 2025

Review of Stream Assessments for Evaluating Ecological Impacts and Benefits

Purpose: This technical note synthesizes common stream assessment methods and highlights their scope, data requirements, and ecological functions to assist practitioners and researchers in selecting appropriate tools for evaluating and managing stream ecosystem impacts and benefits.

30 Apr 2025

Sediment Transport and Morphological Response to Nearshore Nourishment Projects on Wave-Dominated Coasts

Abstract: Nearshore nourishments are constructed for shoreline protection from waves, to provide sediment nourishment to the beach profile, and to beneficially use dredged sediment from navigation channel maintenance. However, it is poorly understood how placement morphology and depth influence nearshore processes operated on wave-dominated coasts. This study investigates the wave fields, sediment transport, and morphological response to three common nearshore nourishment shapes, nearshore berm (elongated bar), undulated nearshore berm, and small discrete mounds, with numerical experiments utilizing the Coastal Modeling System. The nourishments are placed in depths between 3 m and 7 m with a volume of approximately 100,000 m3 and between 400 m and 1000 m in alongshore length. Numerical experiments are carried out in three distinct coastal settings with representative wave climates and geomorphology. Simulation results indicate that shallower, more continuous berms attenuate the most wave energy, while deeper, more diffuse placements retain more sediment. Results from this study improve the understanding of nearshore nourishment shapes and can support decision makers identifying the most appropriate construction technique for future nearshore nourishment projects.

30 Apr 2025

Evaluation of Anchorage for the Bridge Supplemental Set: Uplift Capacity in Weak Soils and Installation Limits for the ROCK-IT Lead Section

Abstract: Two series of experiments were conducted to evaluate the uplift capacity of Bridge Supplemental Set (BSS) anchors in weak/dense soils. Six anchors were installed in two different sites consisting of very soft soils, and tension was applied until uplift. Experimental uplift capacities were compared to theoretical minimum capacities, which proved to be a conservative way to estimate anchor capacity. Minimum average installation torque of 1,750 ft-lb was recommended. Sixteen anchors were installed in six different sites with dense soils. Soils with N values of 22 and higher prohibited anchor installation, indicating that anchors can only be installed in soils with densities up to medium dense sandy and very still clay soils.

30 Apr 2025

Characterization and Rheological Examination of Charleroi Mix 2 Paste Constituents

Abstract: This technical report details the testing plan, methodology, and results used to characterize the paste constituent materials for Charleroi Concrete Mixture 2. Raw materials were characterized for physical and chemical properties of interest including chemical composition, mineralogy, particle size, and absorption capacity. Isothermal calorimetry was used to study the reactivity of constituent materials, and rotational rheology was used to study the impact of various constituent materials on the expected workability and fluidity of the composite paste.

30 Apr 2025

Pier Analysis Tool: User’s Manual

Abstract: This report documents the development of a rapid structural load-capacity assessment capability for ship docking and offloading structures (i.e., piers) and automation of the assessment technique into a user-friendly personal computer–based tool referred to herein as the Pier Analysis Tool (PAT). This capability provides a quick first-cut assessment of the load-bearing capacity of pier structures in terms of maximum allowable ship mooring loads and allowable weights for typical commercial and military vehicles and equipment associated with military discharge operations. The report covers the technical basis for the structural analyses along with detailed computational examples. It also provides a detailed user guide for PAT.