US Army Corps of Engineers
Engineer Research and Development Center Website

Category: Environmental
  • Application of Incremental Sampling Methodology for Subsurface Sampling

    ABSTRACT:  Historically, researchers studying contaminated sites have used grab sampling to collect soil samples. However, this methodology can introduce error in the analysis because it does not account for the wide variations of contaminant concentrations in soil. An alternative method is the Incremental Sampling Methodology (ISM), which previous studies have shown more accurately captures the true concentration of contaminants over an area, even in heterogeneous soils. This report describes the methods and materials used with ISM to collect soil samples, specifically for the purpose of mapping subsurface contamination from site activities. The field data presented indicates that ISM is a promising methodology for collecting subsurface soil samples containing contaminants of concern, including metals and semivolatile organic compounds (SVOCs), for analysis. Ultimately, this study found ISM to be useful for supplying information to assist in the decisions needed for remediation activities.
  • Monitoring Ecological Restoration with Imagery Tools (MERIT): Python-based Decision Support Tools Integrated into ArcGIS for Satellite and UAS Image Processing, Analysis, and Classification

    Abstract: Monitoring the impacts of ecosystem restoration strategies requires both short-term and long-term land surface monitoring. The combined use of unmanned aerial systems (UAS) and satellite imagery enable effective landscape and natural resource management. However, processing, analyzing, and creating derivative imagery products can be time consuming, manually intensive, and cost prohibitive. In order to provide fast, accurate, and standardized UAS and satellite imagery processing, we have developed a suite of easy-to-use tools integrated into the graphical user interface (GUI) of ArcMap and ArcGIS Pro as well as open-source solutions using NodeOpenDroneMap. We built the Monitoring Ecological Restoration with Imagery Tools (MERIT) using Python and leveraging third-party libraries and open-source software capabilities typically unavailable within ArcGIS. MERIT will save US Army Corps of Engineers (USACE) districts significant time in data acquisition, processing, and analysis by allowing a user to move from image acquisition and preprocessing to a final output for decision-making with one application. Although we designed MERIT for use in wetlands research, many tools have regional or global relevancy for a variety of environmental monitoring initiatives.
  • Army R-22 Refrigerant Phase-Out Strategy

    Abstract: R-22 (also known as HCFC-22) is one of the most widely used refrigerants in U.S. Army air-conditioning and refrigeration (AC&R) systems since the phase-out of R-12 refrigerant in 1995. The need to phase out R-22 is at-tributed to its global warming potential and high ozone-depleting capability. The U.S. Army has tens of thousands of aging AC&R systems that will remain dependent on R-22, or one of the recently developed substitutes for R-22, until they reach the end of their operational life. This project conducted a survey to understand the current R-22 usage and types of R-22 AC&R equipment that are in use across Instal-lation Management Command (IMCOM) installations. This study describes several methods to remove or retrofit R-22 from typical AC&R equipment and implementation strategies to meet the stated goal of eliminating R-22 from IMCOM installations. The scope of this project included the review of BUILDER SMS data for IMCOM installations, which included data on 13,000 pieces of comfort cooling equipment for 31 installations. The report also provides an analysis of several R-22 alternatives and their physical properties and compatibility. Mission critical tactical cooling that uses R-22 refrigerant was not within the scope of this project.
  • Comparison of Generic and Proprietary Aquatic Herbicides for Control of Invasive Vegetation : Part 2. Emergent Plants

    Abstract: Aquatic herbicides are one of the most effective and widespread ways to manage nuisance vegetation in the US After the active ingredient is selected, often there are numerous proprietary and generic branded products to select from. To date, limited efforts have been made to compare the efficacy of brand name and generic herbicides head to head; therefore, at tot al of 20 mesocosm trials were conducted to evaluate various 2,4 -D, glyphosate, imazapyr, and triclopyr products against alligatorweed (Alternanthera philoxeroides (Mart.) Griseb.), southern cattail (hereafter referred to as cattail, Typha domingensis Pers.), and creeping water primrose (hereafter referred as primrose, Ludwigia peploides (Kunth) P.H. Raven). All active ingredients were applied to foliage at broadcast rates commonly used in applications to public waters. Proprietary and generic 2,4 -D, glyphosate, imazapyr, and triclopyr were efficacious and provided 39 to 99% control of alligatorweed, cattail and primrose in 19 of the 20 trials. There were no significant differences i n product performance except glyphosate vs. alligatorweed (trial 1, Rodeo vs. Roundup Custom) and glyphosate vs. cattail (trial 1, Rodeo vs. Glyphosate 5.4). These results demonstrate under small -scale conditions, the majority of the generic and proprietary herbicides provided similar control of emergent vegetation, regardless of active ingredient.
  • Estimating the Density of Secretive, At-risk Snake Species on DoD Installations Using an Innovative Approach: IDEASS

    Abstract: The Department of Defense (DoD) expends considerable resources managing and conserving threatened, endangered, or at-risk snake species. Management for these species is often hampered by a lack of basic knowledge regarding their population size and trajectory. The low detectability of most snakes makes it difficult to determine their presence, or to employ traditional methods to estimate abundance. This work demonstrated a novel, simulation-based method, Innovative Density Estimation Approach for Secretive Snakes (IDEASS), for estimating snake density based on systematic road surveys, behavioral observations of snake movement, and spatial movement (radio telemetry) data. This method was used to generate meaningful density estimates for two rare and cryptic snakes of conservation concern, the Southern Hognose and Eastern Diamondback Rattlesnake, at Fort Stewart, Georgia. IDEASS was also applied to an existing dataset to retroactively estimate density of a more common species of management concern, the Western Ratsnake, at Fort Hood, Texas. In all three cases, traditional density estimation via visual surveys and capture-mark-recapture (CMR) failed completely due to lack of captures and re-captures, despite extensive field effort. We conclude that IDEASS represents a powerful tool, and in some cases the only viable method, for estimating density of secretive snakes.
  • Eutrophication Management via Iron-Phosphorus Binding

    Abstract: The presence of phosphorus (P) in excessive quantities can lead to undesired conditions, such as cyanobacterial/algal bloom. The over-enriched hypertrophic conditions or the excess amounts of nutrients (nitrogen and P, P being the primary nutrient of concern) are the major cause of harmful cyanobacterial blooms, which can be toxic and can also lead to oxygen depletion and anoxic respiration (hypoxia) in the hypolimnion. The presence of iron compounds has been shown to bind phosphorus and diminish harmful algal blooms. Therefore, an iron-plates-packed reactor has been designed to reduce P in surface water. This cost-effective and easy-to-install system has shown promising results in phosphorus reduction.
  • Development of a General Anadromous Fish Habitat Model: Phase 2: Initial Model Quantification

    Abstract: The General Anadromous Fish Habitat Model (now the General Salmonid Habitat Model) was developed to assist in the plan formulation process for ecosystem restoration and mitigation projects. The model generates relative differences in habitat quality between proposed alternative future scenarios. In order to provide model development transparency, this report presents the initial quantification phase of the model development process. The draft model depicted in this report is scalable, meaning various parameters may be measured at different landscape scales (for example, reach vs. watershed). The model can be applied (model domain) in watersheds that currently or previously supported salmonid fish species. Application outside of the model domain would need further evaluation to ensure appropriate sensitivity to the new system of interest. Although the model is being developed to explicitly capture changes in fish habitat in response to restoration actions, this model would be appropriate for use in any planning project focused on the restoration of streams, rivers and, estuaries (for example, dam removals, in-stream habitat enhancement), because the parameters are measures of ecosystem level structure, function, and process.
  • Acid Sulfate Soils in Coastal Environments: A Review of Basic Concepts and Implications for Restoration

    Abstract: Acid sulfate soils naturally occur in many coastal regions. However, the oxidation of acid sulfate soils can decrease soil pH to <4.0, affecting vegetation and aquatic organisms. Acid sulfate soil oxidation typically occurs where anaerobic sediments or soils were exposed to aerobic conditions (for example, extended drought, artificial drainage, or dredged material placement in upland areas). Recently, field observations documented the formation of acid sulfate materials at multiple degraded marsh restoration locations (Rhode Island, New Jersey, California) following intentional dredged sediment placement into wetland environments designed to increase marsh elevation. Unlike previous studies of acid sulfate soils, the in situ dredged material did not contain acid sulfate–bearing materials at the time of placement; instead, the interaction between the marsh substrate and the overlying dredged material appears to have caused the formation of acid sulfate soils. These findings highlight the need for additional studies of acid sulfate soil formation and fate—especially within a marsh restoration context. In response, this report provides a review of literature related to acid sulfate soils, discusses preliminary data collected to evaluate acid sulfate material formation following marsh restoration, and identifies knowledge gaps requiring additional research and technical guidance.
  • Aligning Research and Management Priorities for Nitellopsis obtusa (Starry Stonewort)

    Abstract: In 2018, the US Army Corps of Engineers and Washington and Waukesha Counties in Wisconsin hosted a workshop on the invasive macroalga starry stonewort (Nitellopsis obtusa). Leading water resource managers (agencies and commercial applicators), researchers, regulators, and other interested parties discussed issues surrounding starry stonewort invasions in the Great Lakes Region (GLR). Technical sessions presented information on current research, invasion monitoring, early detection, rapid-response efforts, and operational management activities. Research summaries included invasion in Lake Ontario, prediction of invasion risk in Minnesota and Wisconsin using water chemistry data, and bulbil efficacy and distribution modeling in New England. In addition, the workshop offered summaries of attempted chemical and mechanical control tactics. Following presentations on previous studies, workshop participants identified research and management priorities. Critical research gaps identified from this workshop include (a) better understanding of the biology, invasion ecology, and management of starry stonewort; a greater understanding of distribution and movement, especially in the Great Lakes basin; enhanced population monitoring, applied research, and management strategies; and increased technical cooperation across government, academia, industry, and nonprofit organizations. Conclusions from this meeting will help prioritize future efforts focused on the adaptive management of starry stonewort in the United States and Canada.
  • Evaluating Soil Phosphorus Storage Capacity in Constructed Wetlands: Sampling and Analysis Protocol for Site Selection

    Abstract: Soil characteristics determine the capacity of wetlands to sequester phosphorus (P). However, researchers have not yet developed a standard protocol for conducting soil sampling to document the soil phosphorus storage capacity (SPSC) for constructed wetland site selection. In response, the following technical note provides step-by-step instructions for selecting soil sample locations, describing site conditions, conducting soil sampling, and preparing samples for laboratory analysis. This note also includes calculations and interpretation of SPSC.

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