29 Sep 2025

Asset Condition and Probability of Failure Assessment–A Vision for Civil Works: A Document to Guide Collaboration and Innovation for the US Army Corps of Engineers Civil Works Asset Management System

Abstract: The US Army Corps of Engineers (USACE) is rapidly improving its asset management system through a variety of research projects and other work efforts that focus on how risk, condition, and probability of failure are conceived, communicated, and used for decision-making across the agency. As these projects move forward, it is critical that USACE defines a long-term vision for condition and probability of failure assessments across the entire asset management system. This Special Report defines that vision with the goal of achieving consensus and buy-in from a variety of participants that will need to buy-in to achieve success. An additional benefit to identifying an end vision for this work is to identify collaborative opportunities and any gaps that must be addressed to achieve it.

29 Sep 2025

State of Practice and Recommendations to Enhance Probability of Failure Estimates for Civil Works Infrastructure Components

Abstract: As the US Army Corps of Engineers (USACE) continues to improve its asset management system, it is imperative that maintenance investments across its wide infrastructure portfolio are maximizing risk reduction. A key component of risk is probability of failure. Presently, USACE estimates probability of failure for asset components in a variety of ways across business lines, activities, and decision spaces. This document explores the variations in the state of practice for probability of failure estimates across USACE and contrasts them with available best practices and methodologies. The review found several key gaps between the state of practice and best practices, including a lack of component failure and life data useful for time-to-failure parameter estimates, a lack of codified definitions of failure, no clear and consistent guidance for probability of failure estimates across business lines or decision spaces, and no methodologies that account for environmental variation at a facility. These gaps are addressed by a research strategy that compares and contrasts several probability of failure calculation methods using presently available data, identifies relevant life data for future collection, and defines a framework for investing in improved probability of failure assessments at facilities.

29 Sep 2025

Planning-Level Wetland Delineation of Fee-Owned and Trust-Held Properties of the Little Traverse Bay Band of Odawa Indians

Abstract: A planning-level wetland delineation is an important visualization tool for identifying the location and type of wetlands on the landscape, prioritizing areas for conservation and restoration practices, performing alternative analysis, and informing design and development of infrastructure needs. This study used a combination of off-site data analysis and field data collection to identify the location and extent of wetlands on 1,428 acres of fee-owned and trust-held properties of the Little Traverse Bay Band of Odawa Indians (LTBB). The study found that a wide variety of wetlands occur across approximately 313.6 acres, including 65 acres of wetland-nonwetland mosaic features. These wetlands benefit local communities by providing flood risk reduction, habitat for a wide array of species, and improved water quality. Opportunities to increase wetland functions through management activities, including restoration, were identified. This wetland delineation was conducted under the Planning Assistance to States Program, which provides technical assistance to states, tribal communities, and local governments and was administered via an agreement between the US Army Corps of Engineers–Detroit District and the LTBB. This approach has the potential to provide similar information to other tribal groups interested in identifying and delineating wetlands to improve the management of valuable natural resources.

29 Sep 2025

River Training Structure Design Study for Stabilization at Bonanza Bar

Abstract: The Huntington District (LRH) has repeatedly dredged within the navigation channel at Ohio River Mile (RM) 353, adjacent to a location known as Bonanza Bar. An in-channel bar has developed from the placement of the dredged material along the left-descending bank where a bar was historically present. Recently, the frequency of dredging in this area has decreased, suggesting that the presence of the bar is providing some degree of channel constriction. LRH approached the US Army Engineer Research and Development Center to model possible river training structures to provide channel constriction and stabilize the placement of dredged material at Bonanza Bar. A two-dimensional hydraulic numerical model was developed to test structural alternatives by estimating the impacts on the velocities within the main channel, along the length of the bar, and along the mussel habitat within the side channel. Various rock dikes with bank protection were modeled and general design guidance and modeling results are presented. Modeling results indicate increases in main channel velocities and decreases in flow behind the structure for all modeled alternatives. Rootless dikes and bullnose chevrons provide adequate space and flow for side channel presence as opposed to the continuous and notched dikes.

29 Sep 2025

Demonstration of Innovative Patching Technologies for Asphalt Pavement Sustainment

Abstract: iHMA and RapidPatch are two asphalt repair materials developed at the US Army Engineer Research and Development Center (ERDC) to provide asphalt patching materials that are readily available, support rapid return to traffic, and yield high quality, long-term performance solutions. The primary objective of this project was to complete multiple demonstrations of asphalt patching with iHMA and RapidPatch at four installations in different climate zones around the United States. These locations included Fort Wainwright (Alaska), Fort Drum (New York), Fort Huachuca (Arizona), and Bradshaw Army Airfield (Hawai‘i). Overall, demonstrations were completed successfully in all climates, providing an opportunity to evaluate patching technologies in real-world environments, some of which are considered untraditional conditions for repairing asphalt. In total, 111 tubes of iHMA and 90 buckets of RapidPatch were used to complete 55.3 ft3 and 49.8 ft3 of patching, respectively, with patch sizes ranging from 4 ft2 up to 20 ft2. Both iHMA and RapidPatch repairs performed well under accelerated trafficking at all installations, exhibiting no more than 6 mm of rutting (less than 1⁄4 in.) after 1,000 passes of heavy truck loading. After 9 to 12 months of operational traffic and environmental exposure, both iHMA and RapidPatch repairs have performed well.

29 Sep 2025

Introduction of the Pivox System—A Low-Cost, Rapidly Deployable Modular Lidar System

Abstract: Terrestrial light detection and ranging instruments can provide extremely valuable data for a multitude of applications in a wide variety of science and engineering fields. However, terrestrial lidar systems (TLS), are prohibitively expensive for many projects and require significant power and data resources to allow for the collection and transmittal of real-time lidar data, limiting their use in remote applications. To address the need for low-cost lidar data collection capabilities in remote environments, the US Army Corps of Engineers, Engineer Research Development Center, Cold Regions Research and Engineering Laboratory, and Geotechnical and Structures Laboratory (GSL) developed the Pivox System. The Pivox System integrates a Livox lidar sensor to a Raspberry Pi, allowing for real-time data collection, processing, and transmittal using a self-contained unit that also includes the power supply and communications equipment. We present data collected using the Pivox System in three diverse environments to measure changes in snow depth, the presence of lake ice, and erosion during a levee overtopping experiment.

26 Sep 2025

Rapid Assessment Tool for Channel Hydraulics and Floodplain Connectivity

Abstract: This technical note (TN) presents a rapid, nationally applicable web application for analyzing channel hydraulics and floodplain connectivity. The tool uses locally derived relative elevation models (REMs) that allow users to quantify hydraulics, like velocity and shear stress, and floodplain connectivity metrics, like inundation extent and storage volume (Haring and Dougherty, forthcoming).* By delineating cross sections directly from publicly available high-resolution terrain, the tool provides a rapid hydraulic assessment without requiring field survey data and also helps prioritize reaches for more detailed assessments.

25 Sep 2025

Effects of Suspended Sediment on Aquatic Organisms: A Literature Review and Database Effort

Abstract: The US Army Corps of Engineers (USACE) acknowledges that uncertainties and public perceptions regarding the effects of suspended sediment on aquatic organisms, particularly the concentration thresholds associated with harmful effects, present an ongoing challenge to its dredging mission. USACE is actively working to address these challenges through improved monitoring, research, and collaboration to support safer and more sustainable dredging practices. To help mitigate this uncertainty, 159 field- and laboratory-based studies describing the effects of sediment on aquatic organisms were reviewed and compiled in a database. No- and low-effect ecotoxicity data from this review were further analyzed to determine percentiles of effects data and species sensitivity distributions. The analysis indicated corals and freshwater crustaceans were most sensitive, followed by fish, while bivalves and marine crustaceans appeared to be the most tolerant of suspended sediment. This literature review provides a foundational framework for visualizing site-specific suspended sediment thresholds for effects concentrations associated with potential effects on aquatic species. It serves as a starting point for identifying critical data gaps for future research, layering in additional data, refining thresholds, and supporting more informed, site-specific decision-making moving forward.

25 Sep 2025

Considerations and Lessons Learned for Remote Sensing Data Acquisition of Understudied Wetland Vegetation Metrics

Purpose: Traditional field-based methods for monitoring wetland ecosystems are often limited by accessibility and cost, hindering comprehensive assessment of these vital habitats. These wetlands often present challenges for mapping and monitoring due to their size, location, and diverse vegetation types. Therefore, thorough planning and execution are essential for collecting reliable data for analysis and generating meaningful results. To overcome these challenges, we investigated how remote sensing data captured from uncrewed aerial systems (UAS), such as multispectral imagery and lidar, can be effectively used to develop and validate metrics for measuring wetland vegetation characteristics as an alternative to traditional field-based methods.

25 Sep 2025

Evaluation of the Coastal Hazards System (CHS) Probabilistic Framework’s Storm Selection Methods Along the US West Coast

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) evaluates the application of a traditional approach to screening and sampling historical storm events to quantify wave and water-level extremal distributions along the US West Coast, specifically focusing on Washington, Oregon, and California. High-fidelity simulations of storm events enable spatially explicit waves and water-level information in shallow nearshore regions, providing greater context than single-point tide gauges, wave buoys, or hindcast wave nodes in offshore waters. However, the computational expense associated with such simulations necessitates that a select number of events be chosen, ideally representative of the same extreme distribution created by the complete history of storms. Storm selection has previously been shown to be sensitive to the observational record length and the storm sample size but notably also region-specific characteristics such as the common (and uncommon) synoptic weather patterns and the alongshore variability of metocean conditions. The US Army Engineer Research and Development Center (ERDC), Coastal Hazards System (CHS), Stochastic Simulation Technique (SST), which was developed for the quantification of extratropical cyclone (XC) hazards based on extreme value analysis techniques, has previously been used to identify storms for high-fidelity simulations in several regions throughout the United States, including the Great Lakes (Nadal-Caraballo et al. 2012), US mid- and North Atlantic (Nadal-Caraballo et al. 2014; Nadal-Caraballo et al., “North Atlantic Coast,” 2015; Nadal-Caraballo et al., “Statistical Analysis,” 2015), and US South Atlantic (Yawn et al. 2024b) and Gulf of Mexico (Yawn et al. 2024a). However, coastal hazards for the US West Coast and the Pacific Basin are a consequence of multiple compounding oceanographic, meteorologic, and climatic phenomena contributing to waves and water levels with unique characteristics compared to tropical cyclone–dominated coasts. This effort defines total water levels as a combination of still-water levels (SWLs), incident wave runup, and infragravity runup as a proxy for the water elevation experienced at the shoreline during storm events. Dynamic total water levels during extreme events are then separated into individual contributions from oceanic and meteorological phenomena occurring at a variety of timescales, such as seasonal and monthly sea-level anomalies. Results from this analysis highlight future SST developments that will be required as part of a comprehensive CHS-Probabilistic Framework (CHS-PF) for the US West Coast and the Pacific Basin. Specifically, the methodology will need to (1) account for temporal clustering of storm sequences, (2) align with the parameters most relevant to US West Coast coastal storm risk management projects, and (3) develop an approach to create composite storm suites derived from extremes in multiple metocean parameters due to limited overlap between those storms that produce extremes in still water and those storms driving open-coast wave-induced extremes.