24 May 2023

Analysis of Paxton Siphon Frazil Ice Blockage Event during January 2022

Abstract: In early January 2022, the Paxton Siphon, owned and operated by the Nebraska Public Power District, filled with frazil ice creating a blockage that resulted in a rapid upstream stage rise for the Sutherland Canal. An event of this type has never happened in the over 80 years of operating the Paxton Siphon. An analysis of the available weather and canal data suggests a rapid air temperature change resulted in the water becoming supercooled, which combined with the moderately low flows in the canal resulted in an anomalous frazil ice formation event. To address this issue for future cold weather events, a water temperature model was developed using the Hydrologic Engineering Center’s River Analysis System and can be used to determine the spatial extents of the supercooling event using forecasted weather information. In addition, we developed a heat-exchange forecast tool that can be used operationally to screen for potential frazil ice formation periods with a 1-week outlook period.

22 May 2023

Advances in Dredged Material Evaluations for Inland and Ocean Aquatic Placement: Modernized Processes and Supportive Tools

Abstract: As part of the US Army Corps of Engineers’ mission to evaluate and move dredged material (DM) to maintain navigation channels, environmental evaluation of the prospective material is required by the Code of Federal Regulations. While existing guidance manuals provide useful guidance to DM regulators, they are over 30 years old and not reflective of the latest science. However, efforts to update procedures and publish the documents individually or as a combined dredging manual have been thus far unsuccessful. These issues, coupled with a lack of consistent reporting and decision documentation, lead to delays arising from challenges addressing project-specific issues not clearly covered within the existing guidance, revisiting previously resolved issues or negotiating disputes between permitting authorities. This technical report provides a path toward modernization of the environmental compliance aspects of DM evaluation guidance in part through software executables guiding the management and decision process and through a structured, evidence-based approach. The value added is an updated approach to DM testing and evaluation decisions.

19 May 2023

Summary of Ice Jams and Mitigation Techniques in Alaska

Abstract: Ice is an important part of the Alaska ecosystems and can form through dynamic (e.g., frazil) or static (e.g., thermal) processes. In Alaska, both freeze-up and breakup ice jams occur, however breakup jams during the spring snowmelt period are most common. Historically there have been many river systems in Alaska that have chronic ice jam issues. These ice jams have resulted in several significant ice jam floods. There are several ice jam mitigation techniques that can be used to either provide state and local emergency managers warnings of a potential ice jam or reduce the impacts of a jam. Common relatively low-cost mitigation methods that can be implemented prior to a jam forming are monitoring and detection of movement, mechanical or thermal weakening of the ice cover. Permanent measures are also effective and maybe the best option in specific locations. These measures include structures to keep flood waters from inundating areas (e.g., levee) or they can be designed to hold back ice fragments moving downstream (e.g., ice boom and pier structures). Climate change impacts to ice processes are important for Alaska and additional investigations will be needed to quantify the ecologic, hydrologic, and societal impacts.

11 May 2023

Testing of Dry Decontamination Technologies for Chemical, Biological, Radiological, and Nuclear (CBRN) Response

Abstract: This report provides a summary of the results obtained in laboratory-scale testing of dry-decontamination technologies. The purpose of the experiment is to assess nonaqueous technologies to determine the viability of a solution to mitigate chemical, biological, radiological, and nuclear (CBRN) defense, CBRN Response Enterprise, medical casualty care, and cold-weather operational gaps. The Cold Regions Research and Engineering Laboratory (CRREL) assessed the efficacy, via percentage reduction, of four nonaqueous technologies to decontaminate particulate contamination, at three operational temperatures, from three starting challenges. Testing was conducted by CRREL personnel according to protocols developed in conjunction with the Homeland Defense/Civil Support Office Maneuver Support Center of Excellence and the Armed Forces Radiobiology Research Institute (AFRRI) and approved by Joint Program Executive Office CBRN Protection. CRREL subsequently collected data and conducted statistical measures of significance and explored additional questions about the technology capabilities. CRREL personnel then deployed with AFRRI support to Arctic Eagle/Patriot 22 (AE/P-22) for field testing of the technologies and their evaluation from an operational perspective. AE/P-22 allowed for direct, full-scale testing of the technology in conditions approximating a use-case scenario. This report documents the culmination of analysis performed on CRREL- and AFRRI-collected test data results, operational factors, and user inputs.

27 Apr 2023

Stormwater Management Practices, Monitoring, and Maintenance Plan for US Army Garrison at West Point, NY

Abstract: Structural stormwater management practices (SMPs) are designed and installed with the goal of reducing runoff and improving water quality through a variety of built (e.g., underground chamber and filter systems), nature-based and natural features (e.g., rain gardens, swales). In compliance with Section 402 of the US Clean Water Act (CWA), US Army Garrisons at West Point MS4 operators are required to obtain a National Pollutant Discharge Elimination System permit or a New York State Pollutant Discharge Elimination System (SPDES). These permits require development of stormwater management plans to reduce pollutants to meet the appropriate water quality standards. Over 62 structural SMPs have been installed at the US Army Garrison (USAG) to meet permit requirements. Monitoring and maintenance are essential to maintain and understand the effectiveness of these structures, track their maintenance needs, and improve their function. This document provides guidance for conducting stormwater management practice, inspection, and maintenance at the United States Army Garrison at West Point. The objectives are to inform installation managers on general SMP functions and designs, highlight key maintenance triggers affecting SMP functionality, and provide guidance on when and how to conduct inspections and maintenance actions specific to USAG SMPs and in accordance to NYS DEC.

27 Apr 2023

Technical Guide for the Development, Evaluation, and Modification of Wetland Rapid Assessment Methods for the Corps Regulatory Program

Abstract: The US Army Corps of Engineers (Corps) Regulatory Program considers the loss (decrease) and gain (improvement) of wetland functions as part of Clean Water Act Section 404 permitting and compensatory mitigation decisions. To better inform this regulatory decision-making, the Regulatory program needs accurate, transparent, objective, and defensible approaches to assess the function and condition of wetlands. Additionally, wetland assessments must balance the need for objective decision-making with the concurrent need to make Regulatory program decisions in a timely manner. Consequently, it is often necessary to assess wetlands using rapidly attainable proxy measures of ecological function or condition by evaluating a suite of metrics that represent structural and compositional attributes of a wetland. In response, this document describes a set of guidelines to effectively develop, evaluate, and modify wetland assessment methods, specifically for the Corps Regulatory Program.

21 Apr 2023

Early Life-Cycle Prediction of Reliability

Abstract: The intent of this project is to investigate a variety of approaches for the development of a basic model for the early life-cycle prediction of reliability (pre-Milestone A). The United States Department of Defense (DoD) currently utilizes an acquisition framework in which system development advances through a series of checkpoints known as milestones. Each milestone represents a decision point, with Milestone A being the earliest in the life cycle. At Milestone A, also known as the risk-reduction decision, the DoD evaluates design concepts while also committing funds to the maturation of technologies in an effort to mitigate future risks. Typically, little is known about the particular system to be developed at this point in the acquisition life cycle, but DoD regulations require program man-agers to submit system reliability information (OUSD[A&S] 2015). Traditional reliability predictions, however, require extensive knowledge of the system of interest to produce accurate results. This level of knowledge is unavailable at or before Milestone A, there-fore, there is a need to create models and methodologies for the prediction of system reliability. This report provides an overview of a variety of methods investigated to improve the prediction of early life cycle reliability.

21 Apr 2023

Representative Beach Profile Generator

Abstract: The purpose of this Coastal and Hydraulics Engineering Technical Note (CHETN) is to introduce an Esri ArcGIS Pro ArcPy Toolbox entitled “Representative Beach Profile Generator (RBPG)” that generates a single representative profile for a given study area based on elevation profiles. The toolbox aligns and averages input elevation profiles into a single profile based upon a chosen alignment feature. Furthermore, the toolbox allows the user to create maximum and minimum trapezoidal profile approximations for use within numerical models such as Storm-Induced BEAch CHange (SBEACH) and Beach-fx. This CHETN presents a brief description of the toolbox methods and includes a short demonstration of the toolbox’s application to help familiarize the user with inputs, outputs, and possible uses. The RBPG toolbox is available for public download at the link where this paper is hosted with the US Army Engineer Research and Development Center library services (http://dx.doi.org/10.21079/11681/46916).

18 Apr 2023

Comparing Methods for Estimating Water Surface Elevation between Gages in the Lower Mississippi River

Abstract: Predicting a water surface elevation (WSElev) at a particular location has a wide range of applications like determining if a levee will overtop or how much a dike notch will increase water flow into a secondary channel. Five existing methods for predicting the water’s surface, (1) daily slope, (2) average slope, (3) River Analysis System (RAS) 1D, (4) RAS 2D, and (5) Adaptive Hydraulics modeling system (AdH), were used to predict the Mississippi River’s daily water surface from 10 October 2014 to 31 May 2016 at Friar’s Point, Greenville, and Natchez gages. The error, calculated as the model-predicted water surface minus the gage-observed water surface, was compared among the methods. The average slope method, using Helena and Fair Landing gages, and the daily slope method, using either Memphis and Helena or Helena and Arkansas City gages, most closely estimated the observed WSElev. The RAS 1D predictions for Friar Point and Greenville produced more accurate estimates than the RAS 2D model and were the only estimates that did not show a pattern of over- or underestimation. When the daily slope method was applied to gages that were farther apart (Memphis and Arkansas City, Arkansas City and Vicksburg, or Vicksburg and Knoxville), the error became greater than most RAS 1D and 2D predictions. The low error and simple calculations of the daily slope and average slope methods using gages <110 river miles apart make these methods useful for calculating current and historic conditions. The lack of over- or underestimation in the RAS 1D predictions (for locations away from the edges of the model area) make this method a better choice for predicting average WSElevs and a good choice for forecasting future WSElevs.

17 Apr 2023

Low-Logistic Erosion Control Methodologies

Purpose: This paper provides an in-depth review of certain slope stability practices discussed in ERDC/GSL TR-19-44, a technical report titled Erosion Control of Earth Covered Magazines to Maintain Minimum Cover Requirements. At the request of the sponsor, US Army Engineering and Support Center, this document specifically focuses on cost-efficient, low-logistic methods of erosion control such as shotcrete and spray-applied stabilizers.