28 Aug 2024

Validation of Daily Snow Water Equivalent for a Watershed Statistics Tool

Abstract: The Watershed Statistics tool is a tool currently being developed for the Remote Sensing and Geographic Information Systems Center of Expertise’s (RSGIS) Extreme Cold Weather web portal and will allow users to easily access and visualize snow water equivalent (SWE) data. The SWE data available on this tool are derived from passive microwave signals acquired by satellite through a technique known as enhanced passive microwave SWE. This analysis used available in situ SWE measurements from snow study sites in four watersheds across the United States and Canada to determine the accuracy of the data available on the tool at the watershed scale. In situ measurements of SWE were compared with the Watershed Statistics tool’s SWE data based on watershed, land cover, and elevation to determine causes if discrepancies between the satellite-based estimations on the tool and ground-based measurements. The extent to which the data available on the Watershed Statistics tool agreed with in situ measurements was highly variable. SWE data available on the Watershed Statistics tool agreed the least with ground-based measurements made at higher elevations and in areas with denser vegetation. The findings of this comparison are consistent with known limitations of the enhanced passive microwave SWE technique.

26 Aug 2024

FUNWAVE-TVD Testbed: Analytical, Laboratory, and Field Cases for Validation and Verification of the Phase-Resolving Nearshore Boussinesq-Type Numerical Wave Model

Abstract: Over the last couple of decades, advancements in high-performance computing have allowed phase-resolving, Boussinesq-type numerical wave models to be more practical in addressing nearshore coastal wave processes. As such, the open-source FUNWAVE-TVD numerical wave model has become more ubiquitous across all scientific and engineering-focused R&D organizations, including academic, government, and industry partners. In collaboration with the US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory; the University of Delaware; and HR Wallingford, a robust testbed has been developed to allow users to benchmark their applications against new releases of the model. The testbed presented here includes analytical, laboratory, and field cases, to provide guidance on the operational utility of FUNWAVE-TVD and examines numerical convergence, accuracy, and performance in modeling wave generation, propagation, wave breaking, and moving shorelines in nearshore wind-wave applications. A brief discussion on the efficiency of the model across parallel computing platforms is also provided.

22 Aug 2024

Application of Existing Tools to Systematically Identify Nearshore Placement Sites for Beneficial Use of Navigation Sediments in Lake Michigan

Purpose: The Great Lakes includes 140 federally maintained harbors with an annual dredging program of 2–4 million cubic meters (3–5 million cubic yards)[1] of sediment. Many small harbors are not dredged regularly, and there is an undredged backlog of over 9 million cubic meters (12 million cubic yards) of sediment (USACE-LRD 2021). Current policy (Spellmon 2023) is to maximize the beneficial use (BU) of sediment, with a goal of beneficially reusing 70% of the federal navigation dredging volume by 2030 (that is, the 70/30 goal). In the Great Lakes, clean sands have often been placed on beaches or in the nearshore littoral zone to beneficially nourish the shoreline, but since many harbors are not dredged regularly, no plans exist to beneficially reuse dredged sediments. This lack of existing BU plans is particularly true for harbors with finer grained or mixed sediment. To achieve the 70/30 BU goal and support navigation maintenance and coastal management requires a strategic and systematic approach to identifying BU sites. The purpose of the technical note is to (1) provide an approach to identify potential nearshore placement sites using existing information and models; (2) describe available tools for placement site identification, coastal condition information, and the long-term fate of the sediment; and (3) provide a pertinent case study to describe this approach in practice.

15 Aug 2024

Repair Quality Assessment: Spiral 4

Abstract: The Expedient and Expeditionary Airfield Damage Repair (E-ADR), Joint Capability Technology Demonstration (JCTD) program developed, demonstrated, and transitioned a repeatable capability for rapidly repairing bomb-damaged craters at adaptive base locations using logistically friendly technologies, indigenous materials, and less manpower than traditional crater repair methods. Within the E-ADR JCTD program, quality assessment took a major role to ensure quality repairs were performed while meeting the requirements of “just enough, just in time.” Repair criteria for backfill compaction and surface cap quality were developed through extensive testing. These criteria were incorporated into an easy-to-use and deployable smartphone application, the E-ADR Repair Assessment (ERA) application. This report focuses on the backfill quality assessment criteria development, roughness tolerance of surface caps checking procedure, and the development of the ERA application. The criteria and the ERA application both proved successful in the expedient evaluation of backfill and surface cap materials.

13 Aug 2024

Predicting Soil Moisture Content Using Physics-Informed Neural Networks (PINNs)

Abstract: Environmental conditions such as the near-surface soil moisture content are valuable information in object detection problems. However, such information is generally unobtainable at the necessary scale without active sensing. Richards’ equation is a partial differential equation (PDE) that describes the infiltration process of unsaturated soil. Solving the Richards’ equation yields information about the volumetric soil moisture content, hydraulic conductivity, and capillary pressure head. However, Richards’ equation is difficult to approximate due to its nonlinearity. Numerical solvers such as finite difference method (FDM) and finite element method (FEM) are conventional in approximating solutions to Richards’ equation. But such numerical solvers are time-consuming when used in real-time. Physics-informed neural networks (PINNs) are neural networks relying on physical equations in approximating solutions. Once trained, these networks can output approximations in a speedy manner. Thus, PINNs have attracted massive attention in the numerical PDE community. This project aims to apply PINNs to the Richards’ equation to predict underground soil moisture content under known precipitation data.

7 Aug 2024

Traveling Kevel Load Analysis for Inland Locks, Phase I: Previous Failures

Abstract: The US Army Engineer Research and Development Center (ERDC) has begun an investigation of the load conditions experienced by a traveling kevel when moored to a moving barge train. These traveling kevel systems are essential for the safe and efficient use of the US Army Corps of Engineers (USACE) navigation lock inventory. This work is being conducted as part of the Navigation Systems Research Program of the Coastal and Hydraulics Laboratory (CHL). Recent failures of traveling kevels suggest that the existing design guidance for design loads for traveling kevels may need updating. This Coastal and Hydraulics Engineering Technical Note (CHETN) describes the pertinent background information and the current issues related to previous traveling kevel failures.

7 Aug 2024

A Broadscale Assessment of Sentinel-2 Imagery and the Google Earth Engine for the Nationwide Mapping of Chlorophyll a

Abstract: Harmful algal blooms degrade water quality and can adversely impact human and wildlife health. Monitoring these at scale is difficult due to the lack of coincident data. Additionally, traditional field collection methods are labor- and cost-prohibitive, resulting in disparate data collection in capable of capturing the physical and biological variations within waterbodies or regions. This research attempts to alleviate this by leveraging large, public, water quality databases and open-access Google Earth Engine-derived Sentinel-2 imagery to evaluate the practical usability of four common chlorophyll a algorithms as a proxy for detecting and mapping algal blooms nationwide. Chlorophyll a data were aggregated from spatially diverse sites across the continental US between 2019 and 2022. The 2BDA and the NDCI algorithms were the most viable for broadscale mapping of chlorophyll a, which performed moderately well, encompassing highly diverse spatial, temporal, and physical conditions. The most compatible field data acquisition method was the chlorophyll a, water, trichromatic method, uncorrected. Resulting data indicate the feasibility of utilizing band ratio algorithms for broadscale detection and mapping of chlorophyll a as a proxy for HABs, which is valuable when coincident data are unavailable or limited.

6 Aug 2024

Tools and Technical Guidelines for Delineating the Extent of Tidal Waters: Proof of Concept

Abstract: The delineation of shorelines in tidally influenced waters, as well as the inland extent of tidal influence of those waters, is often used to define the extent of federal and/or state jurisdictional boundaries, including the US Army Corps of Engineers’ (USACE) limits of jurisdiction under the Rivers and Harbors Act of 1899 (RHA) and Section 404 of the Clean Water Act. At present, USACE and other practitioners use a variety of field observations and desktop-based data sets, tools, and techniques to identify and delineate the lateral and longitudinal extent of USACE’s jurisdiction under the RHA for tidally influenced waters. Tidal waters, and thus federal jurisdiction under the RHA, “end where the rise and fall of the water surface can no longer be practically measured in a predictable rhythm.” However, the technical standards, definitions, and data to delineate tidal extent are also lacking. The uncertainty and ambiguity in what constitute tidal extent increases litigation risk and decreases repeatability and technical defensibility of USACE decisions. Nationally applicable technical guidance and rapid tools and techniques are needed to increase defensibility and consistency across all coastal USACE districts while also accelerating USACE Regulatory decision-making.

5 Aug 2024

Analysis of Beach Cusp Formation and Evolution Using High-Frequency 3D Lidar Scans

Abstract: Beach cusp characteristics were explored using 15 months of 3D lidar scans collected hourly at the Duck, NC, Field Research Facility. Fourier analyses performed on lidar-derived beach elevation contours generated spatial cusp spectra. Active cusp events identified from the location and magnitude of each spectrum’s peak were used to evaluate conditions during cusp formation and evolution. Cusps primarily developed during normally-incident, long-period, low-energy wave conditions with low frequency spread and reflective beach conditions. Often, however, persistent upper-beach cusps lasted days to months and dynamic lower-beach cusps evolved over individual tidal cycles. At times, beaches exhibiting multiple cusp systems reverted to a single cusp system extending the entire beach when the high-tide waterline reached the upper-beach cusps, with the location and spacing of the resulting lower-beach cusps controlled by the upper-beach cusps. This is consistent with a “morphological coupling” hypothesis that hydrodynamic-morphodynamic feedbacks between the swash and upper-beach cusps can form lower-beach cusps with a related wavelength as the tide falls. However, sometimes the high-tide waterline reaching the upper-beach cusps did not result in a unified beach state. This suggest that morphological coupling is often an important factor in controlling the development of new lower-beach cusps but cannot initiate cusp formation in hydrodynamic conditions outside those favorable for cusp activity.

1 Aug 2024

Detection and Decay of Different Classes of Environmental RNA (eRNA) from Zebrafish (Danio rerio)

Purpose: This technical note contributes to the growing body of knowledge about macroscopic eukaryotic environmental RNA (eRNA) by exploring detection and decay for several different zebrafish (Danio rerio) eRNAs in a mesocosm setting. The study addressed four basic hypotheses: (1) D. rerio would deposit detectable levels of eRNA into water, (2) different classes of eRNA would be detected, (3) different eRNA sequences (for example, loci) would degrade at different rates, and (4) abiotic and biotic factors would influence rates of degradation. For the last hypothesis, we tracked eRNA concentration decay under treatments with different water temperatures and levels of microbiological activity, two factors known to significantly influence environmental DNA (eDNA) decay (Barnes et al. 2014; Lance et al. 2017; Nielsen et al. 2007; Strickler et al. 2015).