14 May 2026

Engineering With Nature® Proving Grounds Innovation Handbook

Abstract: The Engineering With Nature® Proving Grounds Innovation Handbook provides a comprehensive framework for integrating innovative natural and nature-based features and sediment management strategies to address climate-driven hazards and increase resilience in coastal and fluvial environments. Developed through collaboration between engineers, scientist, landscape architects, and U.S. Army Corps of Engineers districts and divisions, the EWN Handbook showcases a diverse collection of projects within the four coasts of the United States and offers the wide range of approaches available to achieve multiple benefits (economic, ecological, and social) through the application of traditional engineering with natural infrastructure solutions. The document aims to offer practitioners ideas on how to incorporate EWN concepts and strategies in all phases to build more resilient, multifunctional projects that protect communities and ecosystems against future natural hazards.

13 May 2026

Processing and Optimization of Global Land Ice Measurements from Space (GLIMS) Glacier Polygon Shapefiles for Army Geospatial Data Model Integration

Abstract: This technical note documents the methodology used to prepare glacier polygon datasets from the Global Land Ice Measurements from Space (GLIMS) database for integration into Army geospatial workflows. The Army Geospatial Data Model contains a feature class within the GGDM (Ground-Warfighter Geospatial Data Model) for permanent snow, defined operationally as snow persisting on the ground for more than two years. However, in cryospheric science, snow that persists across multiple accumulation seasons transitions into firn and ultimately becomes glacial ice. Thus, most “permanent snow” surfaces are more accurately classified as permanent ice, and GGDM does not currently contain a dedicated feature class representing this land-surface category. The GLIMS database provides authoritative, globally maintained glacier and perennial ice extents, making it ideally suited to fill this structural gap in the GGDM schema. The purpose of this work is to (1) transform raw GLIMS glacier polygons into a clean, nonoverlapping, attribute-free dataset; (2) standardize the geometry for compatibility with GGDM; and (3) establish a US Army Engineer Research and Development Center (ERDC)–compliant workflow for maintaining a credible representation of global permanent ice surfaces.

13 May 2026

Geospatial AI (GeoAI) Agent Stack: Router-Based Orchestration and Design Rationale

Abstract: This report summarizes the current state of a router-based, multiagent Geospatial AI (GeoAI) system designed to reliably execute geospatial workflows while retaining the flexibility of large language model (LLM) reasoning. The architecture is intentionally both language-model agnostic and orchestration-framework agnostic to support organizational controls and mandates, and it is designed to operate in air-gapped environments. It uses a domain router to scope tools before the model is invoked; a microrouter to decide whether the system should execute tools, retrieve knowledge, or produce a direct response; and a bounded cycle of execution and validation that supports multistep tool use. The design emphasizes determinism after the model makes decisions, strict boundaries around what the model can “see,” and modularity that keeps core business logic largely independent from orchestration and tool-protocol frameworks. The remainder of this report describes the architecture as implemented today, explains the design rationale, and outlines anticipated future work.

13 May 2026

Beach-fx Version 3.0 User’s Manual

Abstract: The need to strengthen the linkages between engineering analyses (project performance and evolution) and planning functions (alternative analysis and economic justification) with respect to coastal storm damage reduction projects within the US Army Corps of Engineers led to the development of the life-cycle simulation model Beach-fx. Beach-fx provides a comprehensive analytical framework for evaluating the physical performance and economic benefits and costs of shore protection projects, particularly beach nourishment along sandy shores. The model has been implemented as an event-based Monte Carlo life-cycle simulation tool that is run on desktop computers. This report describes the components, purpose, and operational function of the Beach-fx graphical user interface, including navigation within the interface and the organization and specification of all model input and output data.

12 May 2026

A Scalable Algorithm for Dynamic Vector Model Representation Utilizing Time-Series Reduction

Abstract: This document follows a technical report published by the US Army Engineer Research and Development Center–Geospatial Research Laboratory (ERDC-GRL), Time-Series Reduction for Dynamic Vector Model Attribute Representation in a Geographic Information System (ERDC/GRL TR-24-2, Drouillard and Lewis 2024). In that publication, we described the theoretical basis for extracting and modeling raster-format spatiotemporal phenomena for inclusion as a vector model attribute and provided a preliminary Python code example that was unsuitable for large-scale application. This report details the algorithm we subsequently developed to enable global-scale application of the time-series reduction method in service of the Intelligent Environmental Battlefield Awareness (IEBA) project.

12 May 2026

Barge Arrest System for Dams on Inland Waterways: Design Criteria

Abstract: The US Army Engineer Research and Development Center (ERDC), through the Navigation Systems Research Program, has begun developing a barge arrest system to reduce the damage and recovery costs of allisions (impact events) at US Army Corps of Engineers (USACE) lock and dam (L&D) sites. This development effort addresses a need for a mitigation strategy to address allisions from uncontrolled, breakaway barges following accidents that occur on a relatively frequent basis near USACE L&D sites summarized in the USACE Statement of Need 1974. These allisions have caused millions of dollars in recovery and repair costs to both the L&D structure and to navigation industry property (USACE 2005). In extreme situations, barge impacts to multiple gates have inhibited USACE’s ability to regulate water levels. This Coastal and Hydraulics Engineering Technical Note (CHETN) describes the general problem and findings from an initial design charette conducted with USACE subject matter experts (SMEs) across various technical disciplines. This initial design charette focused on the identification of design criteria for the prototype design and potential case study sites.

11 May 2026

Hydrologic Mechanisms for 2022 Yellowstone River Flood and Comparisons to Recent Historic Floods

Abstract: In June 2022, a historic flood event occurred in the headwaters of the Yellowstone River Basin. The flood resulted in millions of dollars in damages and substantial interruptions to Yellowstone National Park. The 2022 flood event was substantially higher in magnitude than other high- peak flow events over the last 30 years. The high discharge was primarily due to the combination of hydrologic mechanisms initiated by rain-on-snow, including a high- elevation snowpack that peaked later than average. However, the contributions of each hydrologic driver, rain and snow, have not been quantified and could be important for understanding future flood events in the region. The contribution of snowmelt to the total terrestrial water input (TWI) varied throughout the area, yet was concentrated in the headwaters of the Yellowstone, Stillwater, and Boulder rivers, along with the headwaters of Rock Creek in Wyoming and Montana. The primary atmospheric contributions to the TWI during the 2022 event were precipitation from moisture transported from the Pacific Ocean that converged over the Greater Yellowstone Area (GYA) and snowmelt from residual snowpack in the northeast part of Yellowstone National Park.

11 May 2026

Native and Invaded-Range Surveys Provide Mixed Support for Enemy-Release of Nymphoides Peltata in the Invaded Range

Abstract: Natural or anthropogenic movement of plant species outside their historical ranges may result in exposure to new environmental conditions and a lack of natural enemies, thus promoting their establishment and spread into new areas. A biogeographical comparison of native and invasive populations can provide insight into the mechanisms of successful invasions and guide effective management strategies, such as biological control, by targeting plant traits that promote invasiveness. We studied the Eurasian aquatic plant, Nymphoides peltata, in situ in the native (China, Korea) and invaded (USA) ranges to determine whether there were differences in natural enemy attack rates (percent leaf damage, frequency of leaf herbivory or disease), productivity (plant cover, reproduction), and leaf traits (leaf elemental content, leaf toughness, dry matter content, specific leaf area) between areas. We also investigated whether there was evidence of a tradeoff between natural enemy attack and growth or reproduction, as would be predicted by invasion theory. Plant cover (23–29 % higher) and reproductive output (eight times more seeds / m2) were consistently higher in the invaded range. Leaf traits consistently differed between ranges, which we would expect if plants in the invaded range had fewer herbivores or other pests. The amount of leaf damage present was similar between ranges, but the frequency of herbivory was 50 % greater, on average, in the native than invaded range. Although we did not quantify suppression of N. peltata by natural enemies, we found evidence of more frequent herbivory in Asia and reduced reproduction and plant cover compared to the USA, which supports further investigation into viability of biological controls.

11 May 2026

High Temperatures will Likely Limit Establishment Success of the Brazilian Peppertree Thrips, Pseudophilothrips Ichini (Thysanoptera: Phlaeothripidae) in the USA, Despite Variation in Microhabitat Thermal Environments

Abstract: Biological control of the invasive tree, Schinus terebinthifolia Raddi, is under investigation to improve conservation and restoration of native plant communities in the continental USA. Release and monitoring of the Brazilian peppertree thrips, Pseudophilothrips ichini, is ongoing in multiple states and climate zones but establishment has been variable. In particular, establishment has not been confirmed in hot, southern Texas locations despite release of over 150,000 thrips across four locations since 2022. To understand whether thermal limitations may preclude use of P. ichini in some regions, we investigated upper and lower thermal limits of P. ichini. We measured upper limit of chill injury zone (ULCIZ) and lower limit of thermal injury zone (LLTIZ) in the laboratory under multiple combinations of temperature and exposure duration then modeled spatial variation in survival based on detailed weather data over 20 years. Additionally, we documented microhabitat variation in temperature extremes in three release sites in south Texas to evaluate whether thermal refugia exist due to variation in microhabitat conditions. Based on LLTIZ and ULCIZ, thermal injury accumulates rapidly at temperatures above 33.08 ± 0.15 ◦C and more slowly at decreasing temperatures below 7.85 ± 0.82 ◦C. Temperatures within the canopy of S. terebinthifolia in the field varied widely and produced a range of predicted mortality, with temperatures at the base of trees that were more moderate in both summer and winter. We determined that, based on the current distribution of S. terebinthifolia in the USA, climate suitability differs between states. Suitability of Florida locations was deemed highly to moderately suitable across seasons, but most Texas locations were unsuitable, including previous release locations in south Texas. These findings suggest releases should continue through most of Florida, in areas of southern California, and locations along the northern gulf coast of Texas. Additionally, augmentative releases of P. ichini during mild seasons may provide opportunities for use of this biological control agent to manage S. terebinthifolia in Texas.

8 May 2026

Development of a Trace Element Signature Library Across a Large Watershed for Assessing Large-Scale Fish Movement Patterns

Abstract: Using trace element or stable isotope analysis has proven to be an effective means to characterize early life history and large-scale movement patterns in fishes. Target species are assessed for analyte concentrations occurring in calcified hard structures and compared to signatures noted from associated watersheds. However, this approach assumes analyte absorption occurs in proportion to their availability, and success relies heavily on the ability to identify unique water chemistry signatures between neighboring watersheds within a defined study area. Our objective was to establish a trace element signature profile for major tributaries occurring within the Mississippi River Valley (MRV). Water samples were obtained from 49 stations and evaluated for the presence and relative concentration of Ba, Sr, Ca, Fe, and Li. Analyte concentrations (milligrams per liter) varied across the sampled stations, although Li occurred at only four stations, primarily in the upper reaches of the MRV, and provided little discriminatory use. Concentrations of Fe and Ca depicted an inverse relationship, with Ca having higher concentrations in the upper third of the MRV while Fe typically had higher concentrations in the lower third. Ratios of Ba:Ca and Sr:Ca (millimole per mole) exhibited the greatest utility for delineating river-specific or reach-specific signatures.