12 Jun 2026

EcoHydraulic Modeling to Inform Sustainable Sediment Management: A Priori Modeling of Reservoir Sediment Release to Estimate Geomorphic and Ecological Response

Abstract: With decreasing storage capacity and increasing operational costs in reservoir management, sediment release is considered a potential alternative to traditional dredging. However, passing sediment through reservoirs may have unexpected effects on downstream river morphology and ecosystem resources. This study uses numerical modeling and a conceptual ecological model to assess the relative effects of sediment load, stream flow magnitude, and grain size distribution in downstream river morphology and aquatic habitat in a case study system of the Big Blue and Kansas Rivers downstream of Tuttle Creek Reservoir, Manhattan, Kansas. The effects of sediment grain size, clearwater flushing rate, and backwater effects from the Kansas River were all found to be relevant in affecting sediment transport and deposition patterns. High-volume water/sediment releases were found to be most effective at emulating historical conditions. Additionally, sediment release was found to increase desirable physical habitat areas that have been lost in the channel. Clearwater flushing further increased the distribution of sediment to support physical habitat creation. These findings can inform sediment release management decisions regarding the timing, duration, and magnitude of sediment releases, particularly in relation to flows at the downstream confluence and for target ecosystem function goals.

12 Jun 2026

Adsorption of the Microbial Exopolysaccharide from Rhizobium Tropici (ATCC 49,672) on Birnessite Facilitates Mn Reduction and Dissolution: Structural Interactions and Morphological Transformation

Abstract: The study addresses the broader question of how microbial exopolysaccharides (EPS) can modulate the reactivity and stability of manganese (Mn) oxides in environmental systems. The objective of this study is to investigate the adsorption process of EPS from Rhizobium tropici on birnessite (MnO2) and mechanisms of induced Mn reduction and dissolution and its further transformation. EPS adsorption isotherms and kinetics on birnessite and the induced dissolution of birnessite were analyzed. Adsorption kinetics could best be described with the Parabolic Diffusion Model while EPS adsorption isotherm was best fitted with the Freundlich model. Adsorbed EPS facilitated Mn reduction and dissolution, releasing Mn²⁺ into the solution. This was also confirmed by fourier transform infrared spectroscopy (FTIR) results with the Mn-O vibrations, O–H groups and C = O carbonyl stretching. The pre-presence of EPS hindered the formation and growth of crystalline structure of birnessite and further hindered its transformation into more stable β-MnO2. The presence of Mn oxide significantly aggregated EPS, forming large aggregates. This study reveals the importance of EPS in influencing both the adsorption behavior and the redox state of Mn, providing significant insights into the interactions of EPS with birnessite in environmental systems.

11 Jun 2026

Proceedings from the Great Lakes Engineering With Nature® Natural and Nature-Based Features Playbook Workshop

Abstract: Communities in the Great Lakes are experiencing increased frequency in coastal flooding and erosion, causing property damage, putting lives at risk, and disrupting local economies. To address these challenges, two workshops were conducted (18 February 2025 [virtual] and 26–27 February 2025 [in person]) to collect knowledge, insights, and feedback from community members, policymakers, and Tribal Nations representatives to inform the development of the Engineering With Nature® Great Lakes Playbook. This report documents the workshop outcomes. The playbook is being designed to advance coastal resilience efforts in the region by identifying natural and nature-based features and multiple lines of resilience strategies that address unique natural hazard-related challenges of the Great Lakes. During the workshops, sustainable, resilient, adaptable, and cost-effective solutions were explored and construction and implementation feasibility were discussed along with regulatory and community challenges that are applicable to coastal risks and opportunities around the Great Lakes. By providing location-appropriate examples and clear guidance on how these nature-based and engineered solutions can be implemented, the playbook will enhance understanding of their potential performance in the region and build confidence among federal, state, and local agencies and Tribal Nations in planning, designing, and implementing these sustainable, adaptable, and cost-effective solutions.

9 Jun 2026

Considerations for Potential Use of an Agent-Based Model in a Petri Network Framework to Model Roost Tree Dynamics of Bats

Purpose: The US Army Corps of Engineers (USACE) is responsible for numerous projects that involve altering or removing wildlife habitat, including habitat of species listed as threatened, endangered, or sensitive (TES). Before initiating a project that may affect TES species, USACE must determine the project’s impact to these species. Understanding the degree of impact, both positive and negative, allows USACE to compare alternatives to reduce negative effects. Because of this, USACE planners need tools to provide accurate assessments of project impacts. Conservation efforts for bats have focused on protecting habitat, especially diurnal roosting trees. Roost trees serve not only as daytime shelter for bats but also for rearing pups until they are able to fly (Barbour and Davis 1969). Determining the impact of habitat change by empirically testing the response of bats to habitat modification has proved difficult because of the effects it may have on TES bats as well as its cost. Simulating the effects of habitat change using computer models provides an excellent data alternative for USACE planners. This technical note explains how agent-based models within a petri network framework can provide USACE planners with information on how habitat modification will affect bat presence or absence.

9 Jun 2026

Considerations for Potential Use of an Agent-Based Model in a Petri Network Framework to Model Roost Tree Dynamics of Bats

Purpose: The US Army Corps of Engineers (USACE) is responsible for numerous projects that involve altering or removing wildlife habitat, including habitat of species listed as threatened, endangered, or sensitive (TES). Before initiating a project that may affect TES species, USACE must determine the project’s impact to these species. Understanding the degree of impact, both positive and negative, allows USACE to compare alternatives to reduce negative effects. Because of this, USACE planners need tools to provide accurate assessments of project impacts. Conservation efforts for bats have focused on protecting habitat, especially diurnal roosting trees. Roost trees serve not only as daytime shelter for bats but also for rearing pups until they are able to fly (Barbour and Davis 1969). Determining the impact of habitat change by empirically testing the response of bats to habitat modification has proved difficult because of the effects it may have on TES bats as well as its cost. Simulating the effects of habitat change using computer models provides an excellent data alternative for USACE planners. This technical note explains how agent-based models within a petri network framework can provide USACE planners with information on how habitat modification will affect bat presence or absence.

8 Jun 2026

Metabarcoding Stem Residue as a Novel Environmental DNA (eDNA) Tool to Identify Spread of Phragmites australis Biological Control Agents

Abstract: Detection and monitoring of biological control agents are critical for evaluating their establishment and spread yet remain challenging when species are cryptic, and densities are low. We assessed whether environmental DNA (eDNA) metabarcoding of stem residues could be used to detect and distinguish the stem-boring noctuid moths Archanara neurica and Lenisa geminipuncta, biological control agents of introduced Phragmites australis released in Ontario, Canada. Using 16S rDNA metabarcoding supplemented with newly generated reference sequences, we analyzed stem residue samples spanning a gradient of quality, including laboratory culture stems (in which agent larvae were present at the time of sampling), confirmed Canadian release sites, and degraded stems from un-managed Phragmites stands in western New York, USA. Target species were consistently detected in laboratory samples, where they comprised 76.7–100% (L. geminipuncta) and 79.2–100% (A. neurica) of Lepidoptera reads. At Canadian release sites, A. neurica was detected in 5 of 11 samples and L. geminipuncta in all 10 samples, with relative read abundances ranging from trace levels to > 90%. Among 27 damaged stems collected in the United States, A. neurica and L. geminipuncta DNA was detected in three samples at very low abundances (0.003–0.12% of total reads), representing the first molecular evidence consistent with trans-border dispersal of these agents. Although detections were rare and do not confirm population establishment, results demonstrate that stem-residue eDNA metabarcoding provides a sensitive, non-invasive tool for early detection and post-release monitoring of biological control agents for invasive plants.

8 Jun 2026

Evaluating Migratory Fish Passage at Partial Migration Barriers in a Social-Ecological Riverscape

Abstract: Anthropogenic partial barriers, such as low-head locks and dams, fragment social-ecological riverscapes and limit migratory fish access to historical spawning habitats, creating trade-offs between ecological conservation and human needs. Fish passage mitigation strategies at three low-head locks and dams on the Cape Fear River, North Carolina, across two contrasting mitigation regimes included (i) a nature-like fishway at LD1, (ii) conservation locking at LD2 and LD3, and (iii) environmental flow prescriptions when locks were inoperable. We evaluated passage of American shad and striped bass using acoustic telemetry and multistate models within a Bayesian framework to estimate upstream passage probabilities under varying flow conditions and management regimes. Passage probabilities for both species were higher in 2013–2015 when conservation locking was conducted. In contrast, passage declined when locks were inoperable and only e-flows allowed passage during dam submergence events in 2022–2023. Flow positively influenced passage, with strongest effects for striped bass; however, the nature-like fishway exhibited consistently low passage probability, and modifications did not improve passage probabilities. Given low passage probabilities during the recent mitigation period, improving longitudinal connectivity for diadromous fish in this river necessitates flexible, integrated operational, structural, and flow-based strategies. Possible future mitigation actions to improve fish passage could include resuming conservation locking, structural interventions such as bypass channel construction and dam height lowering that extends dam submergence, and continued use of e-flows.

5 Jun 2026

Multitemporal Change Detection in the Coastal Zone: Literature Review

Abstract: Beach volume change is a primary metric for quantifying coastal change due to physical and anthropogenic forces. Volumes provide key inputs for the creation and maintenance of regional sediment budgets that inform engineering decisions and ensure the effective management of sediment. This special report provides a comprehensive literature review of the state of the art for developing beach volume change metrics, including methods, software and tools, and common sources of error. The reviewed literature indicates that common proxy-based methods for developing volumes (e.g., shoreline change analysis and beach profile change analysis) are limited in their applicability for study areas with alongshore geomorphic variability. A digital elevation model (DEM) of difference method used with high-resolution (e.g., 1 m DEM) datasets captures volumes over spatially variable geomorphologies more accurately; however, the literature notes limitations related to elevation dataset coverage and geometries used for aggregating volume quantities. Space-time cube methods enable cell-by-cell comparisons of volumes over multiple time periods within defined neighborhoods and provide additional insights, efficiencies, and flexibilities to afore-mentioned methods. A new beach volume framework is required to address limitations related to geomorphic variability, aggregation units, and dataset coverage.

4 Jun 2026

Brief Overview and Guide to Developing Monitoring and Adaptive Management Plans

Purpose: The purpose of this technical note is to summarizes key points on monitoring and adaptive management from the more detailed US Army Corps of Engineers (USACE) report ERDC/EL SR-19-9, “A Systems Approach to Ecosystem Adaptive Management: A USACE Technical Guide” and to provide a quick guide to developing monitoring and adaptive management plans (MAMPs) relevant to ecosystem restoration and mitigation projects. Although this report was written specifically for USACE projects, it is applicable to most restoration and mitigation projects. This guide does not supersede current or future USACE policy or guidance, nor is it applicable to private mitigation projects regulated by USACE.

4 Jun 2026

PFAS Interactions with ASTM Fat Clay and ASTM Ottawa Sand: Implications for Contamination from High-Concentration PFAS Sources Using Fourier Transform Infrared (FTIR) Spectroscopy

Purpose: This technical note seeks to understand the impact of high per- and polyfluoroalkyl substances (PFAS) concentrations on soils, specifically fat clay and Ottawa F-65 sand. This technical note also aims to understand the absorption and retention behaviors of PFAS in these two soil types and how the behaviors may vary because of the soil’s distinct properties.