1 Jul 2026

Development of High-Performance Cold Mix Asphalt for Asphalt Patching

Abstract: Cold mix asphalt (CMA) is commonly used to perform small asphalt patching repairs. It is readily available even when hot mix asphalt (HMA) is not due to distance from a plant or cold weather; it is convenient and can be kept on hand; and it can be used at ambient temperatures. Unfortunately, these advantages are generally offset by marginal performance, especially under heavy loads and at quick return-to-traffic times. For military airfields in particular, both logistical factors and adequate performance are critically important; typical CMAs cannot deliver both, and HMA is not always readily available. Consequently, the objective of this project was to develop a new high-performance CMA that combines convenience and logistical advantages of conventional CMA with the performance expected from HMA. This objective was met using an asphalt-modified polyurethane binder to design cold mix that far outperforms conventional CMA and rivals (exceeds, in some cases) HMA performance, based on both laboratory and full-scale field testing. This two-part material can be field mixed without special mixing equipment; once cured, it is highly elastic, exhibits little temperature sensitivity, and can withstand up to 300 passes of F-15E aircraft traffic with a 3 hr return-to-traffic time (1 in. rutting threshold).

29 Jun 2026

Evaluation of Water Hyacinth (Eichhornia Crassipes) Response to Herbicides Using Unmanned Aerial System Imagery

Abstract: Water hyacinth is a highly invasive aquatic species in the southern United States that requires intensive management through frequent herbicide applications. Quantifying management success in large-scale operations is challenging with traditional survey methods that rely on boat-based teams and can be time-consuming and labor-intensive. In contrast, an unmanned aerial system (UAS) allows a single operator to survey a waterbody more efficiently and rapidly, enhancing both coverage and data collection. Therefore, the objective of this research was to develop remote sensing techniques to assess herbicide efficacy for water hyacinth control in an outdoor mesocosm study. Experiments were conducted in spring and summer 2023 to compare and correlate data from visual evaluations of herbicide efficacy against nine vegetation indices (VIs) derived from UAS-based red-green-blue imagery. Penoxsulam, carfentrazone, diquat, 2,4-D, florpyrauxifen-benzyl, and glyphosate were applied at two rates, and experimental units were evaluated for 6 wk. The carotenoid reflectance index (CRI) had the highest Spearman’s correlation coefficient with visually evaluated efficacy for 2,4-D, diquat, and florpyrauxifen benzyl (> −0.77). The visible atmospherically resistance index (VARI) had the highest correlation with carfentrazone and penoxsulam treatments (> −0.70), and the excess greenness minus redness index had the highest correlation for glyphosate treatments (> −0.83). CRI had the highest correlation coefficient with the most herbicide treatments, and it was the only VI tested that did not include the red band. These VIs were satisfactory predictors of mid-range visually evaluated herbicide efficacy values but were poorly correlated with extremely low and high values, corresponding to nontreated and necrotic plants. Future research should focus on applying findings to real-world (nonexperimental) field conditions and testing imagery with spectral bands beyond the visible range.

29 Jun 2026

Automated Workflows for Airborne Lidar and Photogrammetry Snow Depth Analyses

Abstract: Lidar and photogrammetry techniques provide highly accurate methods for mapping snow depth distribution. However, postprocessing point clouds for snow depth estimation is more complex compared to other earth science applications. This paper presents ice-road-copters (IRC), an open-source Python toolkit that facilitates processing and georeferencing of lidar and photogrammetry point clouds. Case studies demonstrate the tool’s utility across different sensors and platforms over a complex mountainous study area. Results show that a well-configured digital elevation model (DEM) filter effectively removes most noise and outliers from point cloud data. The Simple Morphological Filter (SMRF) generally perform well for ground segmentation but optimal results across diverse terrains may require site-specific tuning, particularly of the elevation threshold and scalar parameters in more complex landscapes. Different methods, including manual depth measurements or snow-free features, can be used to coregister DEMs, reducing vertical errors, eliminating large bias and achieving comparable accuracy to using exposed control surfaces. Derived snow depth rasters showed strong agreement with in situ probe measurements—root-mean-square error (RMSE) of less than 16 cm. Overall, IRC simplifies the transformation of raw point clouds into high-resolution DEMs and value-added snow products, facilitating efficient multitemporal analysis to support military and hydrology applications.

26 Jun 2026

Evaluation of Elevated Band Height for Basal Bark Triclopyr Applications to Schinus terebinthifolia

Abstract: Basal bark application involves applying an oil-soluble herbicide in an oil carrier to the lower 0 to 45 cm of woody stems. For triclopyr, basal bark application typically requires the butoxyethyl ester formulation; however, this cannot be applied when standing water is present, which is common in seasonally flooded wetlands. Recently, the intermediate oil and water-soluble triclopyr acid formulation was registered for use in aquatic sites, allowing for basal bark applications in wetlands where standing water is present. Recent studies indicated that flooding after basal bark treatment can result in triclopyr release to surface waters and subsequent non-target injury. Elevated band application height (i.e., treating a higher band on each stem) may reduce non-target injury potential; however, this modified application technique has not been well tested on woody invasive species. To evaluate this approach, a field study on Brazilian peppertree (Schinus terebinthifolia Raddi) was conducted near Melbourne and Wimauma, FL, on well-established and juvenile rootstocks. Treatments included triclopyr acid at 17, 34, and 69 g L−1 applied in an oil carrier and treatment band heights of 0 to 45 cm and 61 to 107 cm from the groundline. At Melbourne, both band heights treated with 34 or 69 g L−1 resulted in 75% to 100% mortality of mature rootstocks. However, triclopyr applied at 17 g L−1 to the low and elevated band heights resulted in 70% and 11% mortality, respectively. All treatments resulted in 90% to 100% mortality at Wimauma, where the rootstocks were juvenile and much smaller. These findings indicate elevated band heights may be a useful approach for woody plant control and may support an effective management strategy in inundated wetlands that provides better prevention of non-target injury.

26 Jun 2026

Examination of Analytical Shear Stress Predictions for Coastal Dune Evolution

Abstract: Existing process-based models for simulating coastal foredune evolution largely use the same analytical approach for estimating wind-induced surface shear stress distributions over spatially variable topography. Originally developed for smooth, low-sloping hills, these analytical models face significant limitations when the topography of interest exhibits large height-to-length ratios and/or steep, localized features. In this work, we utilize computational fluid dynamics (CFD) to examine the error trends of a commonly used analytical shear stress model for a series of idealized two-dimensional dune profiles. It is observed that the prediction error of the analytical model increases compared to the CFD simulations for increasing height-to-length ratio and localized slope values. Furthermore, we explore two data-driven methodologies for generating alternative shear stress prediction models, namely, symbolic regression and linear, projection-based, non-intrusive reduced-order modeling. These alternative modeling strategies demonstrate reduced overall error but still suffer in their generalizability to broader sets of dune profiles outside of the training data. Finally, the impact of these improvements on aeolian sediment transport fluxes is examined to demonstrate that even modest improvements to the shear stress prediction can have significant impacts on dune evolution simulations over engineering-relevant timescales.

26 Jun 2026

Demonstration of a Remotely Operated Vehicle for Inspecting Holt Lock and Dam

Purpose: This report describes the US Army Engineer Research and Development Center–Environmental Laboratory (ERDC-EL), Robotic Characterization of Battlefield and Operational Environments (RCBOE) Team’s application of a small inspection-class remotely operated vehicle (ROV) to inspect underwater structures at the Holt Lock and Dam located near Tuscaloosa, Alabama.

26 Jun 2026

Water Quality and Sediment Dispersal from Placement of Dredged Material over Former Shell Mining Beds in Mobile Bay, Alabama

Abstract: The US Army Corps of Engineers (USACE) continues to advance regional sediment management practices including Beneficial Use of Dredged Material (BUDM) to reduce dredging costs while improving outcomes for coastal communities and ecosystems. This report describes two field studies conducted to better understand sediment retention and water quality implications associated with in-bay strategic placement of dredged material within former oyster-shell mining areas within Mobile Bay, Alabama. Deployed instrumentation and periodic campaigns of bed and water quality sampling provided data prior to dredged-sediment placement through more than a year after placement. Bed sampling and acoustic sub-bottom profiling indicated that the dredged material deposit was spatially variable in thickness and composition. Placed sediment accumulated quickly, within hours of placement, followed by a 2–4 month period with relatively small adjustments. Beyond 6 months, bed elevation changes became stable at near-background levels. Water quality data indicated that impacts to dissolved oxygen and turbidity associated with the dredged material placement are minor and short-lived. Notably, all water quality parameters remained within the normal range of variability observed within the dynamic Mobile Bay ecosystem. Collectively, these sediment bed and water quality studies support future data driven BUDM decision-making within the Mobile Bay region.

22 Jun 2026

Beach-fx Application Guide: A User’s Trail Guide to Beach-fx

Abstract: Beach-fx is a comprehensive analytical framework used for the evaluation of the physical performance and economic benefits of shore-protection projects related to beach nourishment. The model employs an event-driven Monte Carlo simulation of a project’s life cycle and tracks the physical and economic evolution of the beach. The computational architecture of Beach-fx is set up such that the model relies on external databases that are accessed at run time. There are three external databases: the Input Database (IDB), Output Database (ODB), and Shore Response Database (SRD). The IDB and SRD describe the coastal area under study, the environmental forcing that can impact the area, the structures in the area that are susceptible to damages, and estimates of the morphologic response to the environmental forcing. The ODB stores output data and statistics for each simulation. This document summarizes the steps necessary to prepare the external databases, build a Beach-fx study, and understand the results from model runs. The aim is to provide the Beach-fx user with a comprehensive guide that provides insight to the Beach-fx process from beginning to end.

15 Jun 2026

Environmental Fate of Monosodium Methanearsonate (MSMA)—Part 1: Conceptual Model

Abstract: Monosodium methanearsonate (MSMA), the sodium salt of monomethylarsonic acid (MMA), is used as a selective, broad‐spectrum contact herbicide to control weeds in cotton and a variety of turf. In water, MSMA dissociates into ions of sodium (Na+) and of MMA−, which is the herbicide's active component. Certain soil microorganisms can methylate MMA to dimethylarsinic acid (DMA) other microorganisms can demethylate MMA to inorganic arsenic (iAs). To predict the groundwater concentration of iAs that may result from MSMA application, the processes affecting the environmental behavior of MSMA must be quantified and modeled. There is an extensive body of literature regarding the environmental behavior of MSMA. There is a consensus among scientists that the fate of MMA in soil is controlled by microbial activity and sorption to solid surfaces and that iAs sorption is even more extensive than that of MMA. The sorption and transformation of MMA and its metabolites are affected by several factors including aeration condition, temperature, pH, and the availability of nutrients. The precise nature and extent of each of these processes vary depending on site‐specific conditions; however, such variability is constrained in typical MSMA use areas that are highly managed. Monomethylarsonic acid is strongly sorbed on mineral surfaces and becomes sequestered into the soil matrix. Over time, a greater portion of MMA and iAs becomes immobile and unavailable to soil microorganisms and to leaching. This review synthesizes the results of studies that are relevant for the behavior of MSMA used as a herbicide to reliably predict the fate of MSMA in its use conditions.

15 Jun 2026

Natural vs. Genetically Engineered Microbiomes: Understanding Public Attitudes for Indoor Applications and Pathways for Future Engagement

Abstract: This study examines public preferences for natural microbiomes and support for genetically engineered (GE) microbiomes in the built environment, focusing on the demographic, sociographic, and attitudinal factors that influence these preferences. Using data from a nationally representative survey of 1,000 U.S. adults, we employed hierarchical regression analyses to assess the relative contribution of these variables. While demographic and sociographic factors explained limited variance, topic-specific attitudes, including positive perceptions of microbiome engineering’s potential to improve quality of life, were the most significant predictors of support. Conversely, age, distrust in science, and perceived knowledge negatively influenced support for GE microbiomes, reflecting skepticism among some audiences. The findings highlight the potential of the Responsible Research and Innovation (RRI) framework to align the development of microbiome engineering with societal values and to address diverse public perspectives. This research provides actionable insights for policymakers, researchers, and communicators seeking to navigate the complexities of public engagement with emerging biotechnologies.