30 Sep 2021

Incorporating Terrain Roughness into Helicopter Landing Zone Site Selection by Using the Geomorphic Oscillation Assessment Tool (GOAT) v1.0

ABSTRACT: The Geomorphic Oscillation Assessment Tool (GOAT) quantifies terrain roughness as a mechanism to better explain forward arming and refueling point (FARP) suitability for Army aviation. An empirically driven characteristic of FARP consideration, surface roughness is a key discriminator for site utility in complex terrain. GOAT uses a spatial sampling of high-resolution elevation and land cover data to construct data frames, which enable a relational analysis of component and aggregate site suitability. By incorporating multiple criteria from various doctrinal sources, GOAT produces a composite quality assessment of the areal options available to the aviation commander. This report documents and demonstrates version 1.0 of the GOAT algorithms developed by the U.S. Army Engineer Research and Development Center (ERDC). These details will allow users familiar with R to implement it as a stand-alone program or in R Studio.

30 Sep 2021

Autonomous Transport Innovation (ATI): Integration of Autonomous Electric Vehicles into a Tactical Microgrid

Abstract: The objective of the Autonomous Transport Innovation (ATI) technical research program is to investigate current gaps and challenges then develop solutions to integrate emerging electric transport vehicles, vehicle autonomy, vehicle-to-grid (V2G) charging and microgrid technologies with military legacy equipment. The ATI research area objectives are to: identify unique military requirements for autonomous transportation technologies; identify currently available technologies that can be adopted for military applications and validate the suitability of these technologies to close need gaps; identify research and operational tests for autonomous transport vehicles; investigate requirements for testing and demonstrating of bidirectional vehicle charging within a tactical environment; develop requirements for a sensored, living laboratory that will be used to assess the performance of autonomous innovations; and integrate open standards to promote interoperability and broad-platform compatibility. The research performed resulted in an approach to develop a sensored, living laboratory with operational testing capability to assess the safety, utility, interoperability, and resiliency of autonomous electric transport and V2G technologies in a tactical microgrid. The living laboratory will support research and assessment of emerging technologies and determine the prospect for implementation in defense transport operations and contingency base energy resilience.

29 Sep 2021

Rapid Formation of Iron Sulfides Alters Soil Morphology and Chemistry Following Simulated Marsh Restoration

Abstract: Many marshes show signs of degradation due to fragmentation, lack of sediment inputs, and erosion which may be exacerbated by sea level rise and increasing storm frequency/intensity. As a result, resource managers seek to restore marshes via introduction of sediment to increase elevation and stabilize the marsh platform. Recent field observations suggest the rapid formation of iron sulfide (FeS) materials following restoration in several marshes. To investigate, a laboratory microcosm study evaluated the formation of FeS following simulated restoration activities under continually inundated, simulated drought, and simulated tidal conditions. Results indicate that FeS horizon development initiated within 16 days, expanding to encompass > 30% of the soil profile after 120 days under continuously inundated and simulated tidal conditions. Continuously inundated conditions supported higher FeS content compared to other treatments. Dissolved and total Fe and S measurements suggest the movement and diffusion of chemical constituents from native marsh soil upwards into the overlying sediments, driving FeS precipitation. The study highlights the need to consider biogeochemical factors resulting in FeS formation during salt marsh restoration activities. Additional field research is required to link laboratory studies, which may represent a worst-case scenario, with in-situ conditions.

29 Sep 2021

USACE Advanced Modeling Object Standard: Release 1.0

Abstract: The U.S. Army Corps of Engineers (USACE) Advanced Modeling Object Standard (AMOS) has been developed by the CAD/BIM Technology Center for Facilities, Infrastructure, and Environment to establish standards for support of the Advanced Modeling process within the Department of Defense (DoD) and the Federal Government. The critical component of Advanced Modeling is the objects themselves- and either make the modeling process more difficult or more successful. This manual is part of an initiative to develop a nonproprietary Advanced Modeling standard that incorporates both vertical construction and horizontal construction objects that will address the entire life cycle of facilities within the DoD. The material addressed in this USACE Advanced Modeling Object Standard includes a classification organization that is needed to identify models for specific use cases. Compliance with this standard will allow users to know whether the object model they are getting is graphically well developed but data poor or if it does have the data needed for creating contract documents. This capability will greatly reduce the designers’ efforts to either build an object or search/find/edit an object necessary for the development of their project. Considering that an advanced model may contain hundreds of objects this would represent a huge time savings and improve the modeling process.

29 Sep 2021

Vegetation Community Changes in Response to Phragmites Management at Times Beach, Buffalo, New York

Abstract: Management of invasive phragmites (Phragmites australis [Cav.] Trin. Ex Steud.) in the United States has proven challenging over the last several decades. Various methods for control exist, but integrated approaches appear to have the most success. However, documentation of vegetation community–wide responses to these approaches remains limited. This study monitored plant community changes at Times Beach, New York, over a five-year period. In concert with mowing and thatch removal in all areas, the study evaluated two herbicides separately and together, representing three experimental treatment areas (TAs), for control efficacy by measuring plant community structure. Phragmites was targeted for treatments, avoiding native and nonproblematic non-native species when possible, to preserve beneficial habitat during phragmites control efforts. Monitoring results showed significant drops in phragmites relative cover, relative frequency, and importance values due to integrated management, regardless of herbicide treatment, with corresponding increases in these same values for native and other plant species. This suggests that prudent removal of phragmites is compatible with beneficial plant restorative efforts to maintain and improve habitat in infested areas.

29 Sep 2021

Inundation Depth and Duration Impacts on Wetland Soils and Vegetation: State of Knowledge

Abstract: The following synthesizes studies investigating plant and soil responses to increased inundation in order to support ecosystem restoration efforts related to the alteration of natural wetland hydrodynamics. Specific topics include hydrologic regimes, soil response to inundation, and implications for vegetation communities exposed to increased water depths. Results highlight the important interactions between water, soils, and vegetation that determine the trajectory and fate of wetland ecosystems, including the development of feedback loops related to marsh degradation and subsidence. This report then discusses the knowledge gaps related to implications of inundation depth, timing, and duration within an ecosystem restoration context, identifying opportunities for future research while providing source materials for practitioners developing restoration projects.

29 Sep 2021

Threatened, Endangered, and At-Risk Species for Consideration into Climate Change Models in the Northeast

Abstract: This special report provides a selection process for choosing priority species using the specific focus of high-elevation, forested habitats in the North Atlantic to demonstrate the process. This process includes criteria for choosing invasive species to incorporate into models, given the predicted spread of invasive plant species because of climate change. Discussed in this report are the US Army Corps of Engineers’ Threatened and Endangered Species Team portal, the US Fish and Wildlife Service’s Information for Planning and Consultation Portal, the nonprofit organization Partners in Flight’s watch list, the US Geological Survey’s Biodiversity Information Serving Our Nation model, and NatureServe’s interagency effort Landfire. The data linked this montane habitat with a species of conservation concern, Cartharus bicknelli and the endangered squirrel Glaucomys sabrinus as target species and with Elaeagnus umbellate, Robinia pseudoacacia, Rhamnus cathartica, and Acer planoides as invasive species. Incorporating these links into the climate change framework developed by Davis et al. (2018) will create predictive models for the impacts of climate change on TER-S, which will affect land management decisions in the region.

29 Sep 2021

Backward Erosion Testing: Magnolia Levee

Abstract: Using a confined flume device, an experimental study investigated the critical horizontal gradient of soils obtained from a site identified as potentially vulnerable to backward erosion piping (BEP). Tests were conducted on glacial outwash material obtained from a sand and gravel quarry in the vicinity of Magnolia Levee in the community of Magnolia, OH. The two bulk samples collected from the quarry had similar grain-size distributions, grain roundness, and depositional environments as the foundation materials beneath the levee. Samples were prepared at various densities and subjected to gradual increases of flow in a wooden flume with an acrylic top until BEP was observed. The critical average horizontal gradient ranged from 0.21 to 0.30 for a bulk sample with a coefficient of uniformity of 1.6, while tests conducted on a bulk sample with a coefficient of uniformity of 2.5 yielded critical average horizontal gradients of 0.31 to 0.36. The critical average gradients measured during these tests compared favorably to values in the literature after applying adjustments according to Schmertmann’s method.

28 Sep 2021

Backward Erosion Progression Rates from Small-Scale Flume Tests

Abstract: Backward erosion piping (BEP) is an internal erosion mechanism by which erosion channels progress upstream, typically through cohesionless or highly erodible foundation materials of dams and levees. As one of the primary causes of embankment failures, usually during high pool events, the probability of BEP-induced failure is commonly evaluated by the U.S. Army Corps of Engineers for existing dams and levees. In current practice, BEP failure probability is quantitatively assessed assuming steady state conditions with qualitative adjustments for temporal aspects of the process. In cases with short-term hydraulic loads, the progression rate of the erosion pipe may control the failure probability such that more quantitative treatment of the temporal development of erosion is necessary to arrive at meaningful probabilities of failure. This report builds upon the current state of the practice by investigating BEP progression rates through a series of laboratory experiments. BEP progression rates were measured for nine uniform sands in a series of 55 small-scale flume tests. Results indicate that the pipe progression rates are proportional to the seepage velocity and can be predicted using equations recently proposed in the literature.

28 Sep 2021

Synthesis and Characterization of Biological Nanomaterial/Poly(vinylidene fluoride) Composites

Abstract: The properties of composite materials are strongly influenced by both the physical and chemical properties of their individual constituents, as well as the interactions between them. For nanocomposites, the incorporation of nano-sized dopants inside a host material matrix can lead to significant improvements in mechanical strength, toughness, thermal or electrical conductivity, etc. In this work, the effect of cellulose nanofibrils on the structure and mechanical properties of cellulose nanofibril poly(vinylidene fluoride) (PVDF) composite films was investigated. Cellulose is one of the most abundant organic polymers with superior mechanical properties and readily functionalized surfaces. Under the current processing conditions, cellulose nanofibrils, as-received and 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) oxidized, alter the crystallinity and mechanical properties of the composite films while not inducing a crystalline phase transformation on the 𝛾 phase PVDF composites. Composite films obtained from hydrated cellulose nanofibrils remain in a majority 𝛾 phase, but also exhibit a small, yet detectable fraction of 𝛼 and ß PVDF phases.