12 Sep 2022

Application of Clean Dredged Material to Facilitate Contaminated Sediment Source Control

Abstract: Navigation channels, turning basins, and other US Army Corps of Engineers (USACE)–managed navigation infrastructure often serve as repositories for contaminated sediment from off-site sources. As much as 10% of the material that USACE dredges on an annual basis is contaminated such that it requires additional and more costly management (for example, rehandling and placement in managed confined disposal facilities). Presence of contaminated sediments constrain potential management options resulting in additional costs and opportunity loss from the inability to beneficially use the material. One potential solution is applying clean dredged material to stabilize and isolate contaminated sediment sources, preventing further transport and introduction to USACE-managed infrastructure. This document summarizes a comprehensive literature review of laboratory and field case studies relevant to using clean dredged material to isolate or stabilize contaminated sediments, focusing on the physical, chemical, and biological parameters critical to establishing its feasibility and long-term effectiveness. Potentially effective engineering control measures were also reviewed where erosion and site hydrodynamics are facilitating the transport of contaminated sediments to USACE-maintained navigation infrastructure. This literature review documents and summarizes those factors considered in establishing feasibility and long-term effectiveness of the approach as well as the applicable engineering tools employed and constraints encountered.

29 Aug 2022

Remote Sensing Capabilities to Support EWN® Projects: An R&D Approach to Improve Project Efficiencies and Quantify Performance

PURPOSE: Engineering With Nature (EWN®) is a US Army Corps of Engineers (USACE) Initiative and Program that promotes more sustainable practices for delivering economic, environmental, and social benefits through collaborative processes. As the number and variety of EWN® projects continue to grow and evolve, there is an increasing opportunity to improve how to quantify their benefits and communicate them to the public. Recent advancements in remote sensing technologies are significant for EWN® because they can provide project-relevant detail across a large areal extent, in which traditional survey methods may be complex due to site access limitations. These technologies encompass a suite of spatial and temporal data collection and processing techniques used to characterize Earth's surface properties and conditions that would otherwise be difficult to assess. This document aims to describe the general underpinnings and utility of remote sensing technologies and applications for use: (1) in specific phases of the EWN® project life cycle; (2) with specific EWN® project types; and (3) in the quantification and assessment of project implementation, performance, and benefits.

29 Aug 2022

Financing Natural Infrastructure: South Bay Salt Pond Restoration Project, California

PURPOSE: This technical note is part of a series collaboratively produced by the US Army Corps of Engineers (USACE)–Institute for Water Resources (IWR) and the US Army Engineer Research and Development Center (ERDC). It describes the funding and financing process for the South Bay Salt Pond Restoration Project in San Francisco Bay, California and, like the other technical notes in this series, documents successful examples of funding natural infrastructure projects. The research effort is a collaboration between the Engineering With Nature® (EWN®) and Systems Approach to Geomorphic Engineering (SAGE) programs of USACE. A key need for greater application of natural infrastructure approaches is information about obtaining funds to scope, design, construct, monitor, and adaptively manage these projects. As natural infrastructure techniques vary widely by location, purpose, and scale, there is no standard process for securing funds. The goal of this series is to share lessons learned about a variety of funding and financing methods to increase the implementation of natural infrastructure projects.

18 Aug 2022

Geospatial Suitability Indices (GSI) Toolbox: User’s Guide

Abstract: Habitat suitability models have been widely adopted in ecosystem management and restoration to assess environmental impacts and benefits according to the quantity and quality of a given habitat. Many spatially distributed ecological processes require application of suitability models within a geographic information system (GIS). This technical report presents a geospatial toolbox for assessing habitat suitability. The geospatial suitability indices (GSI) toolbox was developed in ArcGIS Pro 2.7 using the Python 3.7 programming language and is available for use on the local desktop in the Windows 10 environment. Two main tools comprise the GSI toolbox. First, the suitability index (SIC) calculator tool uses thematic or continuous geospatial raster layers to calculate parameter suitability indices using user-specified habitat relationships. Second, the overall suitability index calculator (OSIC) combines multiple parameter suitability indices into one overarching index using one or more options, including arithmetic mean, weighted arithmetic mean, geometric mean, and minimum limiting factor. The result is a raster layer representing habitat suitability values from 0.0–1.0, where zero (0) is unsuitable habitat and one (1) is ideal suitability. This report documents the model purpose and development and provides a user’s guide for the GSI toolbox.

17 Aug 2022

Ecological Model Development: Toolkit for interActive Modeling (TAM)

Overview: Ecological models provide crucial tools for informing many aspects of ecosystem restoration and management, ranging from increasing understanding of complex ecological functions to prioritizing restoration sites and quantifying benefits for project reporting. The diversity of ecosystem types and restoration objectives often precludes the use of existing models; as such, model development is commonly required to inform restoration decision-making. Index-based habitat models are a common approach for assessing ecosystem condition. These models relate habitat quality to species’ distributions. Habitat suitability (quality) typically ranges on a scale from 0 to 1. Habitat models have been developed to assess habitat suitability for specific taxa, communities, or ecosystem functions. Restoration-project timelines often require that these models be developed rapidly and in conjunction with many external stakeholders or partners. Here, the Toolkit for interActive Modeling (TAM) is proposed as a platform for rapidly developing index-based models, particularly for US Army Corps of Engineers’ (USACE) ecosystem-restoration or mitigation planning processes. The TAM is a consistent quantitative framework that allows for development of a generic platform for index-based model development

17 Aug 2022

Evaluation of Methods for Monitoring Herbaceous Vegetation

Abstract: This special report seeks to advance the field of ecological restoration by reviewing selected reports on the processes, procedures, and protocols associated with monitoring of ecological restoration projects. Specifically, this report identifies selected published herbaceous vegetation monitoring protocols at the national, regional, and local levels and then evaluates the recommended sampling design and methods from these identified protocols. Finally, the report analyzes the sampling designs and methods in the context of monitoring restored herbaceous vegetation at US Army Corps of Engineers (USACE) ecosystem restoration sites. By providing this information and the accompanying analyses in one document, this special report aids the current effort to standardize data-collection methods in monitoring ecosystem restoration projects.

15 Aug 2022

Identification and Preventative Treatment of Overwintering Cyanobacteria in Sediments: A Literature Review

Abstract: Freshwaters can experience growths of toxin-producing cyanobacteria or harmful algal blooms (HABs). HAB-producing cyanobacteria can develop akinetes, which are thick-enveloped quiescent cells akin to seeds in vascular plants or quiescent colonies that overwinter in sediment. Overwintering cells produce viable “seed beds” for HAB resurgences and preventative treatments may diminish HAB intensity. The purpose of this literature review was to identify (1) environmental factors triggering germination and growth of overwintering cells, (2) sampling, identification, and enumeration methods, and (3) feasibility of preventative algaecide treatments. Conditions triggering akinete germination (light ≥0.5 µmol m-2s-1, temperature 22-27℃) differ from conditions triggering overwintering Microcystis growth (temperature 15-30℃, nutrients, mixing). Corers or dredges are used to collect surficial (0-2 cm) sediment layers containing overwintering cells. Identification and enumeration via microscopy are aided by dilution, sieving, or density separation of sediment. Grow-out studies simulate environmental conditions triggering cell growth and provide evidence of overwintering cell viability. Lines of evidence supporting algaecide efficacy for preventative treatments include (1) field studies demonstrating scalability and efficacy of algaecides against benthic algae, (2) data suggesting similar sensitivities of overwintering and planktonic Microcystis cells to a peroxide algaecide, and (3) a mesocosm study demonstrating a decrease in HAB severity following preventative treatments. This review informs data needs, monitoring techniques, and potential efficacy of algaecides for preventative treatments of overwintering cells.

12 Aug 2022

Swan Island: Monitoring and Adaptive Management Plan

Abstract: Swan Island is a 10.12 ha island located in the Maryland waters of the Chesapeake Bay. Because of its value as a natural wave break for the town of Ewell on nearby Smith Island, as well as the ongoing erosion and subsidence of the island, in 2019 US Army Corps of Engineers (USACE)–Baltimore District placed 45,873 m³ of dredged sediment and planted 200,000 marsh plants. This restoration provided an opportunity to quantify the engineering (that is, resilience) and ecological performance of the island, postplacement. The lack of quantitative data on the performance of natural features such as islands has led to perceived uncertainties that are often cited as barriers to implementation. To address these data gaps, a multidisciplinary collaboration of five government entities identified project objectives and monitoring parameters through a series of mediated workshops and then developed a conceptual model to articulate those parameters and the linkages between them. This monitoring and adaptive management plan (MAMP) documents those monitoring parameters and procedures and can serve as an example for other scales, regions, and research questions. Documenting research and monitoring efforts may help to foster widespread acceptance of nature-based solutions such as islands.

12 Aug 2022

Development of a Three-Dimensional Vegetative Loss Mechanism for the Geophysical Scale Transport Multi-Block Hydrodynamic Sediment and Water Quality Transport Modeling System (GSMB)

PURPOSE: The US Army Engineer Research and Development Center’s (ERDC) Environmental Laboratory (EL) and Coastal and Hydraulics Laboratory (CHL) have completed several large scale hydrodynamic, sediment and water quality transport studies. These studies have been successfully executed utilizing the Geophysical Scale Transport Modeling System (GSMB), which is composed of multiple process models (Figure 1). Due to being directly and indirectly linked within the GSMB framework, the US Army Corps of Engineers (USACE) accepted wave, hydrodynamic, sediment, and water quality transport models are both directly and indirectly linked within the GSMB framework.

11 Aug 2022

Environmental Evaluation and Management of Dredged Material for Beneficial Use: A Regional Beneficial Use Testing Manual for the Great Lakes

Abstract: The Environmental Evaluation and Management of Dredged Material for Beneficial Use: A Regional Beneficial Use Testing Manual for the Great Lakes (a.k.a. Great Lakes Beneficial Use Testing Manual) is a resource document providing technical guidance for evaluating the suitability of dredged sediment for beneficial use in aquatic and terrestrial environments in the Great Lakes region. The procedures in this manual are based on the Environmental Laboratory extensive research, working with US Army Corps of Engineers (USACE) Great Lakes districts, state resource agencies, and local stakeholders seeking to develop dredged material beneficial use alternatives consistent with regional needs and goals. This manual is the first guidance document developed by USACE for evaluating the environmental suitability of dredged material specifically for beneficial use placements. It provides a tiered framework for evaluating the environmental suitability of aquatic and upland beneficial uses consistent with the Inland Testing Manual and the Upland Testing Manual. This manual is intended to serve as a regional platform to increase collaborative problem-solving and endorse a common understanding of the scientific and institutional practices for evaluating dredged material for any beneficial use. Dredged sediment may be managed as a valuable resource, with great potential to create economic, environmental, and social benefits.