29 Jul 2022

Chitosan as a Coagulant and Precipitant of Algae Present in Backwater

PURPOSE: : The purpose of this technical note (TN) is to highlight the current state of knowledge of algal flocculation by chitosan and identify data gaps existing between specific algal characteristics and chitosan binding efficiency. Published relationships and correlations between the quality of backwaters and the prevalence of algae, a baseline for flocculation efficiency of microalgae, and ideal treatment instances for algal removal by way of chitosan flocculation and precipitation will be identified.

29 Jul 2022

Organogel Synthesis Towards Electrochemical Sensing Applications

PURPOSE: The purpose of this study was to synthesize a novel and tunable organogel system capable of stand-alone use with integration via electrochemical tools for the detection of aerosol particles.

27 Jul 2022

Synthesis of 2-methoxypropyl benzene for epitope imprinting

PURPOSE: To synthesize a novel, yet simple, compound for use in the development of a molecularly imprinted sensor for field-portable detection of harmful algal bloom toxins. BACKGROUND: Harmful algal blooms (HABs) are occurring with increasing frequency and severity across the globe in part due to climate change and anthropogenic pollution (Bullerjahn et al. 2016). HABs produce several classes of toxins; however, microcystins (MCs) are the most commonly studied (Lone et al. 2015) and can be potent toxins with LD50s in the range of 50 μg/kg (Puddick et al. 2014). Sample analysis in laboratories, typically by high-pressure liquid chromatography tandem mass spectrometry (HPLC-MS/MS) or by Enzyme Linked Immunosorbent Assays (ELISAs) (USEPA 2015). These analytical techniques are highly sensitive and selective for the given toxins; however, the time it takes to collect, transfer, prepare, and analyze a sample before the data can be reported is significant; often, multiple days is the most expeditious.

27 Jul 2022

Environmental Effects of Sediment Release from Dams: Conceptual Model and Literature Review for the Kansas River Basin

PURPOSE: Passing sediment from reservoirs to downstream channels is a potential solution to aging infrastructure and reservoir storage capacity loss, which is a pressing challenge nationwide. The US Army Corps of Engineers (USACE) sediment management actions at reservoirs such as flushing may drive ecological changes that may be beneficial or detrimental to downstream ecosystems. However, these potential effects are currently not well understood or documented. An exploratory study of the potential ecological effects of releasing sediment downstream from reservoirs is presented in this technical note (TN). We focus on Tuttle Creek Reservoir in Kansas and use fish species as indicators of ecological change. A literature review of Kansas fishes was conducted and three conceptual models illustrating potential benefits or negative effects of releasing sediment downstream of Tuttle Creek Reservoir was developed. Some fish species may benefit from sediment releases, while others may be negatively affected. Further research and tools are needed to develop a greater understanding of these effects.

25 Jul 2022

The Application of Engineering With Nature® Principles in Colorado Flood Recovery

Purpose: This technical note features river-based restoration projects that incorporate Engineering with Nature® (EWN®), Natural and Nature Based Features (NNBF) approaches in the Front Range of Colorado as part of a comprehensive flood recovery program to protect life and property.

25 Jul 2022

Engineering With Nature® in Fluvial Systems

Purpose: The purpose of this technical note is to underline the growing need for Engineering With Nature® (EWN) guidance for inland fluvial systems. In comparison to the EWN coastal initiatives, guidance, and technical publications, emphasis on inland fluvial systems has been primarily focused on larger river systems, rather than smaller and intermediate-sized tributary systems. As EWN continues to expand its offerings and support inland systems, there is a strong need to fill data gaps and offer case study examples from underrepresented issues across different hydro-physiographic regions and ecosystems. Accordingly, this technical note offers background on the growing need for riverine EWN guidance as well recommendations moving forward to help address those needs.

21 Jul 2022

Implementing Endangered Species Act (ESA) Section 7 (a)(1) Conservation Planning During US Army Corps of Engineers (USACE) Coastal Engineering

Purpose: This technical note was developed by the US Army Engineer Research and Development Center–Environmental Laboratory (ERDC-EL) to provide guidance to the US Army Corps of Engineers (USACE) on implementing Endangered Species Act* (ESA) Section 7(a)(1) conservation planning, in coordination with the US Fish and Wildlife Service (USFWS) and the National Marine Fisheries Service (NMFS) during coastal engineering projects. USACE expends ~$200–$300 million each year on compliance, conservation, and other activities associated with the ESA (USACE 2022), and these expenditures often exceed those of other federal agencies (for example, US Bureau of Land Management) that have jurisdiction over far greater land holdings than USACE. To streamline the ESA compliance process, lower costs, and generate more positive outcomes for federally listed threatened and endangered species (TES), USACE was directed in June 2015 by the Deputy Commanding General (DCG) for Civil and Emergency Operations to proactively identify and incorporate conservation benefits into all projects when and where opportunities arise, under the authority of Section 7(a)(1) of the ESA (USACE 2015). The DCG identified Section 7(a)(1) conservation planning as a mechanism to efficiently achieve project purposes, create environmental value, and streamline the ESA Section 7(a)(2) consultation process

20 Jul 2022

Scenario Analyses in Ecological Modeling and Ecosystem Management

Purpose: Ecosystem management and restoration practitioners are challenged with complex problems, diverse project goals, multiple management alternatives, and potential future scenarios that change the systems of interest. Scenario analysis aids in forecasting, evaluating, and communicating outcomes of potential management actions under different plausible conditions, such as land-use change or sea level rise. However, little guidance exists for practitioners on the utility and execution of scenario analysis. Therefore, this technical note highlights the usefulness of scenario analysis as a tool for addressing uncertainty in potential project outcomes. The mechanics of the scenario-analysis process are explained, and examples of different types of scenario analyses are described for context on the breadth of its use. Lastly, two hypothetical case studies of scenario analysis in ecological modeling are presented showing a semiquantitative approach for assessing anadromous fish and a quantitative approach examining freshwater mussel habitat. Overall, this technical note provides a brief review of the utility and application of scenario analyses in the context of ecological modeling and ecosystem management decision-making.

13 Jul 2022

Effects of Impure Water Sources on Early-Age Properties of Calcium Sulfoaluminate Cements for Rapid Airfield Damage Recovery

Abstract: In austere environments with limited access to clean water, it is advantageous to use nonpotable water for construction (i.e., mixing water for concrete.) In rapid-response situations such as rapid airfield damage recovery (RADR), the use of calcium sulfoaluminate (CSA) cements is beneficial for expedient pavement repairs because of their rapid strength gain characteristics. However, the hydration products formed by CSA cements are substantially different from those formed by ordinary portland cement and might react differently to impurities that water sources may contain. A laboratory study component investigated the application of various salts and impure sources of mixing water with commercially available CSA cement-based products. A field component studied the application of naturally occurring impure water sources for RADR. Recommendations are made for implementation of impure mixing water for RADR using commercially available flowable fill and concrete products made with CSA cement.

12 Jul 2022

Boronic Acid Functionalized Ferrocene Derivatives Towards Fluoride Sensing

Abstract: In this technical report (TR), a robust, readily synthesized molecule with a ferrocene core appended with one or two boronic acid moieties was designed, synthesized, and used toward F- (free fluoride) detection. Through Lewis acid-base interactions, the boronic acid derivatives are capable of binding with F- in an aqueous solution via ligand exchange reaction and is specific to fluoride ion. Fluoride binding to ferrocene causes significant changes in fluorescence or electrochemical responses that can be monitored with field-portable instrumentation at concentrations below the WHO recommended limit. The F- binding interaction was further monitored via proton nuclear magnetic resonance spectroscopy (1H-NMR). In addition, fluorescent spectroscopy of the boronic acid moiety and electrochemical monitoring of the ferrocene moiety will allow detection and estimation of F- concentration precisely in a solution matrix. The current work shows lower detection limit (LOD) of ~15 µM (285 μg/L) which is below the WHO standards. Preliminary computational calculations showed the boronic acid moieties attached to the ferrocene core interacted with the fluoride ion. Also, the ionization diagrams indicate the amides and the boronic acid groups can be ionized forming strong ionic interactions with fluoride ions in addition to hydrogen bonding interactions.