9 Jul 2020

PUBLICATION NOTICE: Rapid Tidal Reconstruction for the Coastal Hazards System and StormSim Part I: Coastal Texas and Louisiana

Abstract: incorporating a rapid tidal time series reconstruction and prediction subroutine within the Coastal Hazards System (CHS) framework. The CHS (https://chs.erdc.dren.mil) is a national database and web tool that provides probabilistic coastal hazard analysis (PCHA) products developed from regional studies such as the North Atlantic Coast Comprehensive Study (Nadal-Caraballo et al. 2015; Cialone et al. 2015). PCHA considers hazards due to both tropical and extratropical cyclones, depending on the storm climatology of the region of interest. The CHS supports feasibility studies, probabilistic design of coastal structures, flood risk management for coastal communities, and critical infrastructure. In the case of tropical cyclones (TCs) or hurricanes, both the timing of landfall and the level of the astronomical tide at the landfall location are critical in determining the magnitude of the still water level (i.e., storm surge + wave setup + astronomical tide). Therefore, a robust and accurate tide prediction methodology is needed to provide reliable reconstruction of tidal time series for historical, synthetic, and forecasted hurricane scenarios. This CHETN also discusses the quantification and validation of the Advanced Circulation (ADCIRC) tidal constituent database in the coastal Texas and Louisiana region as well as the implementation of the tidal reconstruction program Unified Tidal analysis (UTide) in the CHS framework.

1 Jul 2020

PUBLICATION NOTICE: Laboratory spiking process of soil with various uranium and other heavy metals

Abstract: Laboratory studies using metal spiked soils are challenging due to soil heterogeneity. This work provides an easy, quick, precise, and accurate technique for the preparation of spiked soils for laboratory research. The process described spiking soil with various uranium species and other heavy metals for laboratory scale pilot experiments under various biogeochemical conditions. The procedure involves grinding both dry soil and metal chemicals into the fine powder. The spiked soil mixture was further homogenized through a modified splitting and combining of the sample by diagonal flipping using plastic sheeting. Comparison of measured concentrations with theoretical values were obtained with <20% precision and accuracy. However, tradition spiking method with metal solution of-ten yielded high heterogeneous spiked soils due to strong metal adsorption in soils. Re-drying and re-grinding of soils were required following the spiking in order to homogenize treated soils, generating inhalable particulates. Thus appropriate personal protective equipment and practices are required for the safety concern. The present method with metal salt powder proved a safe, useful, quick, accurate and precise, and homogenized soil spiking method.

1 Jul 2020

PUBLICATION NOTICE: Spatial Analysis of Precipitation and Snow Water Equivalent Extremes for the Columbia River Basin

Abstract: Recent advances in the spatial statistics of extremes and model calibration were applied to develop and deliver areal-exceedance estimates for precipitation (PREC), by season and duration, and snow water equivalent (SWE), by cool season month and for the water year, for 758 delineated sub-basins of the Columbia River Basin (CRB), which correspond to a new CRB hydrology model watershed delineation. Understanding that future US Army Corps of Engineers, Northwestern Division, mission requirements may change, project execution also included the development and delivery of an application guidance document to credibly compute areal-exceedance estimates, including uncertainty, for PREC or SWE for any arbitrary area within the CRB. R, a free software environment for statistical computing and graphics (https://www.r-project.org/), and QGIS, a free and open source geographic information system (https://qgis.org/en/site/index.html), were the primary tools used for product development and delivery. The following R software packages were primarily used during project execution: evd, Glmnet, maps, raster, rgdal, SDMTools, sp, and SpatialExtremes.

1 Jul 2020

PUBLICATION NOTICE: Laboratory Simulation of Uranium Metal Corrosion in Different Soil Moisture Regimes

Abstract: A novel laboratory simulation system has been developed for the study of the corrosion of uranium metal in soils. Corrosion and transportation of depleted uranium (DU) as the metal undergoes weathering as a buried material within the soil environment. The corrosion of uranium metal in soil was not well understood due to the gas-liquid-solid phase of the soil. This study presents a novel method to investigate the change of uranium species during the process of process of oxidation of metallic uranium in these environments. Compared with other techniques used for the study of environmental corrosion of metals in soils, this method has the ad-vantage of low secondary uranium pollution, no energy consumption, and ease of operation. The simulation system has been used for the following studies: • Simultaneously simulate the corrosion of uranium metal in different soil moisture regimes • Study the influence of biogeochemical factors on the corrosion of uranium metal • Investigate the change of uranium species during oxidation.

1 Jul 2020

PUBLICATION NOTICE: Electrokinetic-Enhanced Phytoremediation of Uranium-contaminated Soil Using Sunflower and Indian Mustard

Abstract: Electrokinetic-enhanced phytoremediation is an effective technology to decontaminate heavy metal contaminated soil. In this study, we examined the effects of electrokinetic treatments on plant uptake and bioaccumulation of U from soils with various U sources. Redistribution of uranium in soils as affected by planting and electrokinetic treatments was investigated. The soil was spiked with 100mg kg⁻¹ UO₂, UO3, and UO₂(NO₃)₂. After sunflower and Indian mustard grew for 60 days, 1 voltage of direct-current was applied across the soils for 9 days. The results indicated that U uptake in both plants were significantly enhanced by electrokinetic treatments from soil with UO₃ and UO₂(NO₃)₂. U was more accumulated in roots than in shoots. Electrokinetic treatments were effective on lowering soil pH near the anode region. Overall, uranium (U) removal efficiency reached 3.4–4.3% from soils with UO₃ and uranyl with both plants while that from soil with UO₂ was 0.7–0.8%. Electrokinetic remediation treatment significantly enhanced the U removal efficiency (5–6%) from soils with UO₃ and uranyl but it was 0.8–1.3% from soil with UO₂, indicating significant effects of U species and electrokinetic enhancement on U bioaccumulation. This study implies the potential feasibility of electrokinetic-enhanced phytoremediation of U soils with sunflower and Indian mustard.

1 Jul 2020

PUBLICATION NOTICE: A Novel Laboratory Simulation System to Uncover the Mechanisms of Uranium Upward Transport in a Desert Landscape

Abstract: After depleted uranium (DU) is deposited in the environment, it corrodes producing mobile uranium species. The upward transport mechanism in a desert landscape is associated with the dissolution/precipitation of uranium minerals that vary in composition and solubility in soil pore water. The objective of this study is to develop the laboratory column simulation to investigate the upward transport mechanism with cyclic capillary wet-ting and drying moisture regimes. Results showed that evaporation driven upward transport occurred even during the first 2 months of wetting-drying regimes. Evaporation driven upward transport may control the U movement in the soil profile in an arid climate. The new system did not generate any uranium-containing wastewater. • Simulates the upward transport process of pollutants with different pollution levels and species. • Simultaneously simulate the transport process of multiple pollutants simultaneously. • Evaluate the influence of biogeochemical factors on pollutant transport such as various cations and anions (Ca, Mg and carbonates) in water.

25 Jun 2020

PUBLICATION NOTICE: Rapid Screening for Uranium in Soils Using Field Portable X-Ray Fluorescence Spectrometer : A Comparative Study

Abstract: Depleted uranium armor penetrating munitions are used on testing and training ranges leading to elevated concentrations of U in range soils. To prevent exposure on secure areas contaminated with depleted uranium (DU) hotspots, easy and rapid screening methods are needed. This study explores the feasibility of field portable X-ray fluorescence (FPXRF) spectrometry as a fast screening tool for locating hotspots of DU in the field. Direct comparisons of results were made for U concentrations in soil obtained using a FPXRF spectrometry and measurement of U using ICP-MS after acid digestion. The environmental samples included both field range contaminated soils collected at a munition testing facility and soils spiked with uranium dioxide, uranium trioxide and uranyl nitrate. Using U concentrations measured with ICP-MS from split samples, FPXRF operating procedures and conditions such as analysis time, soil moisture content, sample amount, and sample packing factors were optimized. Results showed that the FPXRF technique yielded similar U concentrations as ICPMS measurements after acid digestion in both standard soil (NIST) samples and DU contaminated range soils. In field contaminated soils, U values with FPXRF were 88.8% of the measurements with ICPMS with a significant correlation (R2: 0.98, n=8). Sample preparation affected the uranium concentration measurements made with FPXRF in the laboratory and in the field. A loose packing of the samples in the sample containers, higher sample occupancy as well as low soil moisture yielded significantly high U concentrations by 4-5%, 15-50% and 43%, respectively. The measured soil U concentrations were not affected by the variation of the sample analysis time. This study suggests that FPXRF is a promising fast screening tool for field DU hotspots as well as detection/location of penetrators in the fields that can increase the ability to rapidly and inexpensively manage DU on ranges and help ensure sustainable use of DU munitions on testing and training ranges.

25 Jun 2020

PUBLICATION NOTICE: Characterization of eroded mud aggregates with the Flume Imaging Camera System (FICS) and its added value to sediment management projects

Abstract: The goal of this technical note (TN) is to describe the functionality and added research value of the Flume Imaging Camera System (FICS), a US Army Engineer Research and Development Center (ERDC)-developed system designed to measure the size of sediment particles immediately following erosion.

25 Jun 2020

PUBLICATION NOTICE: Applications of value modeling to USACE Civil Works and beyond

Abstract: The US Army Corps of Engineers (USACE) Civil Works (CW) portfolio includes $250 billion worth of capital assets. As infrastructure ages and budgets change, new asset management (AM) investment strategies are required to support the maintenance, repair, and replacement (MR&R) of these assets while also providing the greatest value to the USACE and to the Nation. Shrinking budgets and increased scrutiny of government expenditures drive efforts to determine how best to optimize government funds for infrastructure improvement. As a result, USACE-CW AM seeks to create a value model capable of calculating the benefit of MR&R project alternatives regardless of business line. Furthermore, USACE-CW seeks to explore whether such a value model could be used for the generation of defensible budgets that consistently bring high value to the USACE and to the Nation. Thus, this special report reviews past USACE CW efforts to develop a value model for decision analytics. This report also provides an introduction to value modeling while covering applications of value modeling in multiple areas, including AM and portfolio decision analytics.

25 Jun 2020

PUBLICATION NOTICE: Hydraulic Analysis and Modeling of Navigation Conditions near the Mississippi River Bridges in Vicksburg, Mississippi

Abstract: The River and Estuarine Engineering Branch of the Coastal and Hydraulics Laboratory developed a two-dimensional numerical model of the Mississippi River near Vicksburg, MS, using Adaptive Hydraulics to investigate navigation conditions through the Interstate 20 and Old Highway 80 Bridges reach. A focus of the study was determining the Marshall Brown Dikes impact to velocities and navigation through the reach. Proposed dikes, focused on improving currents, were also tested to determine if they are a feasible option to improve navigability through the bridges. A second proposed alternative, a levee to protect the articulated concrete mattress (ACM) field, was also simulated to determine if flood damage to the ACM field could be successfully reduced without negatively impacting navigation. Velocity data from 2008 throughout the reach of concern were used for validation along with water surface elevation data from 2008, 2011, 2016, and 2018. The Marshall Brown Dikes were shown to have a localized impact on velocities near the dikes, but the changes to the velocity downstream near the bridge were negligible for all tested flow rates. Simulations of the proposed dikes did not result in an improvement to navigation conditions, but the proposed levee was successful in decreasing velocities and depths over the ACM field.