12 Aug 2021

Rapid Tidal Reconstruction with UTide and the ADCIRC Tidal Database

Abstract: The quantification of storm surge is vital for flood hazard assessment in communities affected by coastal storms. The astronomical tide is an integral component of the total still water level needed for accurate storm surge estimates. Coastal hazard analysis methods, such as the Coastal Hazards System and the StormSim Coastal Hazards Rapid Prediction System, require thousands of hydrodynamic and wave simulations that are computationally expensive. In some regions, the inclusion of astronomical tides is neglected in the hydrodynamics and tides are instead incorporated within the probabilistic framework. There is a need for a rapid, reliable, and accurate tide prediction methodology to provide spatially dense reconstructed or predicted tidal time series for historical, synthetic, and forecasted hurricane scenarios. A methodology is proposed to combine the tidal harmonic information from the spatially dense Advanced Circulation hydrodynamic model tidal database with a rapid tidal reconstruction and prediction program. In this study, the Unified Tidal Analysis program was paired with results from the tidal database. This methodology will produce reconstructed (i.e., historical) and predicted tidal heights for coastal locations along the United States eastern seaboard and beyond and will contribute to the determination of accurate still water levels in coastal hazard analysis methods.

12 Aug 2021

Quantifying Functional Increases Across a Large-Scale Wetland Restoration Chronosequence

Abstract: Over 300,000 ha of forested wetlands have undergone restoration within the Mississippi Alluvial Valley region. Restored forest successional stage varies, providing opportunities to document wetland functional increases across a large-scale restoration chronosequence using the Hydrogeomorphic (HGM) approach. Results from >600 restored study sites spanning a 25-year chronosequence indicate that: 1) wetland functional assessment variables increased toward reference conditions; 2) restored wetlands generally follow expected recovery trajectories; and 3) wetland functions display significant improvements across the restoration chronosequence. A functional lag between restored areas and mature reference wetlands persists in most instances. However, a subset of restored sites have attained mature reference wetland conditions in areas approaching or exceeding tree diameter and canopy closure thresholds. Study results highlight the importance of site selection and the benefits of evaluating a suite of wetland functions in order to identify appropriate restoration success milestones and design monitoring programs. For example, wetland functions associated with detention of precipitation (a largely physical process) rapidly increased under post restoration conditions, while improvements in wetland habitat functions (associated with forest establishment and maturation) required additional time. As the wetland science community transitions towards larger scale restoration efforts, effectively quantifying restoration functional improvements will become increasingly important.

11 Aug 2021

Predicting the Impact of Aqueous Ions on Fate and Transport of Munition Compounds

Abstract: A model framework for natural water has been developed using computational chemistry techniques to elucidate the interactions between solvated munition compounds and eight common ions in naturally occurring water sources. The interaction energies, residence times, coordination statistics, and surface preferences of nine munition related compounds with each ion were evaluated. The propensity of these interactions to increase degradation of the munition compound was predicted using accelerated replica QM/MM simulations. The degradation prediction data qualitatively align with previous quantum mechanical studies. The results suggest that primary ions of interest for fate and transport modeling of munition compounds in natural waters may follow the relative importance of SO₄²⁻, Cl⁻ ≫ HCO₃⁻, Na⁺, Mg²⁺ > Ca²⁺, K⁺, and NH₄⁺.

11 Aug 2021

Preparative, Extraction, and Analytical Methods for Simultaneous Determination of Legacy and Insensitive Munition (IM) Constituents in Aqueous, Soil or Sediment, and Tissue Matrices

Abstract: No standard method exists for determining levels of insensitive munition (IM) compounds in environmental matrices. This project resulted in new methods of extraction, analytical separation and quantitation of 17 legacy and 7 IM compounds, daughter products of IM, and other munition compounds absent from USEPA Method 8330B. Extraction methods were developed for aqueous (direct-injection and solid-phase extraction [SPE]), soil, sediment, and tissue samples using laboratory-spiked samples. Aqueous methods were tested on 5 water sources, with 23 of 24 compounds recovered within DoD QSM Ver5.2 limits. New solvent extraction (SE) methods enabled recovery of all 24 compounds from 6 soils within QSM limits, and a majority of the 24 compounds were recovered at acceptable levels from 4 tissues types. A modified chromatographic treatment method removed analytical interferences from tissue extracts. Two orthogonal high-performance liquid chromatography-ultraviolet (HPLC-UV) separation methods, along with an HPLC–mass spectrometric (HPLC-MS) method, were developed. Implementing these new methods should reduce labor and supply costs by approximately 50%, requiring a single extraction and sample preparation, and 2 analyses rather than 4. These new methods will support environmental monitoring of IM and facilitate execution of risk-related studies to determine long-term effects of IM compounds.

10 Aug 2021

Record Package Guidance: Best Practices

Abstract: The CAD/BIM Technology Center receives numerous questions throughout the year regarding the development of a Record Package that shows as-built conditions. While the Center does produce Standards on the look and organization of CAD drawings that are used to show as-built conditions, users wanted guidance on the Record Package development. The Chicago District had undertaken the development of such guidance, but a formal document was never officially released. The CAD/BIM Community of Practice (CoP) Work Structure Committee finished this guidance and their efforts are reflected in this document.

9 Aug 2021

Metal Accumulation Capacity in Indigenous Alaska Vegetation Growing on Military Training Lands

Abstract: Permafrost thawing could increase soil contaminant mobilization in the environment. Our objective was to quantify metal accumulation capacities for plant species and functional groups common to Alaskan military training ranges where elevated soil metal concentrations were likely to occur. Plant species across multiple military training range sites were collected. Metal content in shoots and roots was compared to soil metal concentrations to calculate bioconcentration and translocation factors. On average, grasses accumulated greater concentrations of Cr, Cu, Ni, Pb, Sb, and Zn relative to forbs or shrubs, and bioconcentrated greater concentrations of Ni and Pb. Shrubs bioconcentrated greater concentrations of Sb. Translocation to shoots was greatest among the forbs. Three native plants were identified as candidate species for use in metal phytostabilization applications. Elymus macrourus, a grass, bioconcentrated substantial concentrations of Cu, Pb, and Zn in roots with low translocation to shoots. Elaeagnus commutata, a shrub, bioconcentrated the greatest amounts of Sb, Ni, and Cr, with a low translocation factor. Solidago decumbens bio-concentrated the greatest amount of Sb among the forbs and translocated the least amount of metals. A combination of forb, shrub, and grass will likely enhance phytostabilization of heavy metals in interior Alaska soils through increased functional group diversity.

9 Aug 2021

Simultaneous Mapping of Coastal Topography and Bathymetry from a Lightweight Multicamera UAS

Abstract: A low-cost multicamera Unmanned Aircraft System (UAS) is used to simultaneously estimate open-coast topography and bathymetry from a single longitudinal coastal flight. The UAS combines nadir and oblique imagery to create a wide field of view (FOV), which enables collection of mobile, long d Coastal mapping, multiview stereo (MVS), nearshore morphology, remote sensing, structure from motion (SfM), Unmanned Aircraft Systems (UAS)well timeseries of the littoral zone suitable for structure-from motion (SfM), and wave speed inversion algorithms. Resultant digital surface models (DSMs) compare well with terrestrial topographic lidar and bathymetric survey data at Duck, NC, USA, with root-mean-square error (RMSE)/bias of 0.26/–0.05 and 0.34/–0.05 m, respectively. Bathymetric data from another flight at Virginia Beach, VA, USA, demonstrates successful comparison (RMSE/bias of 0.17/0.06 m) in a secondary environment. UAS-derived engineering data products, total volume profiles and shoreline position, were congruent with those calculated from traditional topo-bathymetric surveys at Duck. Capturing both topography and bathymetry within a single flight, the presented multicamera system is more efficient than data acquisition with a single camera UAS; this advantage grows for longer stretches of coastline (10 km). Efficiency increases further with an on-board Global Navigation Satellite System–Inertial Navigation System (GNSS-INS) to eliminate ground control point (GCP) placement. The Appendix reprocesses the Virginia Beach flight with the GNSS–INS input and no GCPs.

6 Aug 2021

Print Time vs. Elapsed Time: A Temporal Analysis of a Continuous Printing Operation for Additive Constructed Concrete

Abstract: In additive construction, ambitious goals to fabricate a concrete building in less than 24 hours are attempted. In the field, this goal relies on a metric of print time to make this conclusion, which excludes rest time and delays. The task to complete a building in 24 hours was put to the test with the first attempt at a fully continuous print of a structurally reinforced additively constructed concrete (ACC) building. A time series analysis was performed during the construction of a 512 ft2 (16’x32’x9.25’) building to explore the effect of delays on the completion time. This analysis included a study of the variation in comprehensive layer print times, expected trends and forecasting for what is expected in future prints of similar types. Furthermore, the study included a determination and comparison of print time, elapsed time, and construction time, as well as a look at the effect of environmental conditions on the delay events. Upon finishing, the analysis concluded that the 3D-printed building was completed in 14-hours of print time, 31.2- hours elapsed time, a total of 5 days of construction time. This emphasizes that reports on newly 3D-printed constructions need to provide a definition of time that includes all possible duration periods to communicate realistic capabilities of this new technology.

5 Aug 2021

Changes in Climate and Its Effect on Timing of Snowmelt and Intensity-Duration-Frequency Curves

Abstract: Snow is a critical water resource for much of the U.S. and failure to ac-count for changes in climate could deleteriously impact military assets. In this study, we produced historical and future snow trends through modeling at three military sites (in Washington, Colorado, and North Dakota) and the Western U.S. For selected rivers, we performed seasonal trend analysis of discharge extremes. We calculated flood frequency curves and estimated the probability of occurrence of future annual maximum daily rainfall depths. Additionally, we generated intensity-duration-frequency curves (IDF) to find rainfall intensities at several return levels. Generally, our results showed a decreasing trend in historical and future snow duration, rain-on-snow events, and snowmelt runoff. This decreasing trend in snowpack could reduce water resources. A statistically significant increase in maximum streamflow for most rivers at the Washington and North Dakota sites occurred for several months of the year. In Colorado, only a few months indicated such an increase. Future IDF curves for Colorado and North Dakota indicated a slight increase in rainfall intensity whereas the Washington site had about a twofold increase. This increase in rainfall in-tensity could result in major flood events, demonstrating the importance of accounting for climate changes in infrastructure planning.

4 Aug 2021

An Assessment of Long-Term, Multipurpose Ecosystem Functions and Engineering Benefits Derived from Historical Dredged Sediment Beneficial Use Projects

Abstract: The beneficial use of dredged materials improves environmental outcomes while maximizing navigation benefits and minimizing costs, in accordance with the principles of the Engineering With Nature® (EWN) initiative. Yet, few studies document the long-term benefits of innovative dredged material management strategies or conduct comprehensive life-cycle analysis because of a combination of (1) short monitoring time frames and (2) the paucity of constructed projects that have reached ecological maturity. In response, we conducted an ecological functional and engineering benefit assessment of six historic (>40 years old) dredged material–supported habitat improvement projects where initial postconstruction beneficial use monitoring data was available. Conditions at natural reference locations were also documented to facilitate a comparison between natural and engineered landscape features. Results indicate the projects examined provide valuable habitat for a variety of species in addition to yielding a number of engineering (for example, shoreline protection) and other (for example, carbon storage) benefits. Our findings also suggest establishment of ecological success criteria should not overemphasize replicating reference conditions but remain focused on achieving specific ecological functions (that is, habitat and biogeochemical cycling) and engineering benefits (that is, storm surge reduction, navigation channel maintenance) achievable through project design and operational management.