14 Sep 2022

Ecological Model Development: Evaluation of System Quality

PURPOSE: Ecological models are used throughout the US Army Corps of Engineers (USACE) to inform decisions related to ecosystem restoration, water operations, environmental impact assessment, environmental mitigation, and other topics. Ecological models are typically developed in phases of conceptualization, quantification, evaluation, application, and communication. Evaluation is a process for assessing the technical quality, reliability, and ecological basis of a model and includes techniques such as calibration, verification, validation, and review. In this technical note (TN), we describe an approach for evaluating system quality, which generally includes the computational integrity, numerical accuracy, and programming of a model or modeling system. Methods are presented for avoiding computational errors during development, detecting errors through model testing, and updating models based on review and use. A formal structure is proposed for model test plans and subsequently demonstrated for a hypothetical habitat suitability model. Overall, this TN provides ecological modeling practitioners with a rapid guide for evaluating system quality.

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.

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.

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.

4 Aug 2022

Supporting Bank and Near-bank Stabilization and Habitat Using Dredged Sediment: Documenting Best Practices

Abstract: In-water beneficial use of dredged sediment provides the US Army Corps of Engineers (USACE) the opportunity to increase beneficial use while controlling costs. Beneficial use projects in riverine environments include bank and near-bank placement, where sediments can protect against bank erosion and support habitat diversity. While bank and near-bank placement of navigation dredged sediment to support river-bank stabilization and habitat is currently practiced, documented examples are sparse. Documenting successful projects can support advancing the practice across USACE. In addition, documentation identifies data gaps required to develop engineering and ecosystem restoration guidance using navigation-dredged sediment. This report documents five USACE and international case studies that successfully applied these practices: Ephemeral Island Creation on the Upper Mississippi River; Gravel Island Creation on the Danube River; Gravel Bar Creation on the Tombigbee River; Wetland Habitat Restoration on the Sacramento-San Joaquin River Delta; and Island and Wetland Creation on the Lower Columbia River Estuary. Increased bank and near-bank placement can have multiple benefits, including reduced dredge volumes that would otherwise increase as banks erode, improved sustainable dredged sediment management strategies, expanded ecosystem restoration opportunities, and improved flood risk management. Data collected from site monitoring can be applied to support development of USACE engineering and ecosystem restoration guidance.

18 Feb 2022

Approaches to Identify and Monitor for Potential Acid Sulfate Soils in an Ecological Restoration Context

Purpose: Potential acid sulfate soils include materials with the capacity to generate acidity under certain environmental conditions. As such, these soils can pose challenges to ecological restoration projects occurring in wetlands and nearshore environments. To provide guidance for ecosystem restoration practitioners, the following technical note describes acid sulfate soil formation and distribution and then describes techniques for identifying and monitoring acid sulfate soil conditions prior to and following implementation of restoration activities. Finally, this technical note outlines a number of tools and recently published resources to help avoid unintended consequences of acid sulfate soil disturbance and achieve ecological restoration objectives.

5 Nov 2021

Water Level Management for Enhanced Fish and Wildlife Habitat Production in Upper Mississippi River Navigation Pools: An Engineering with Nature® Review of Practice

Abstract: There is a long history of fish and wildlife management associated with Upper Mississippi River navigation dams owned and operated by the US Army Corps of Engineers (USACE). Many operational changes have been made to improve aquatic habitat, with recent emphasis on pool-scale drawdowns to enhance wetland benefits without affecting navigation or other uses. This special report describes projects successfully incorporating Engineering With Nature® principles in a review of the physical setting and historical fish and wildlife habitat management efforts using Upper Mississippi River System navigation dams. We reviewed 80 years of adaptation and lessons learned about how to integrate navigation operations and wildlife management. Several experiments have revealed the capacity to produce thousands of hectares of emergent and submersed aquatic plants, restoring much-needed riparian habitat for a variety of aquatic, wetland, and avian species.

13 Oct 2021

Engineering With Nature®: Supporting Mission Resilience and Infrastructure Value at Department of Defense Installations

Abstract: This book illustrates some of the current challenges and hazards experienced by military installations, and the content highlights activities at seven military installations to achieve increased resilience through natural infrastructure.

1 Oct 2021

Environmental Factors Affecting Coastal and Estuarine Submerged Aquatic Vegetation (SAV)

Abstract: Submerged aquatic vegetation (SAV) growing in estuarine and coastal marine systems provides crucial ecosystem functions ranging from sediment stabilization to habitat and food for specific species. SAV systems, however, are sensitive to a number of environmental factors, both anthropogenic and natural. The most common limiting factors are light limitation, water quality, and salinity, as reported widely across the literature. These factors are controlled by a number of complex processes, however, varying greatly between systems and SAV populations. This report seeks to conduct an exhaustive examination of factors influencing estuarine and coastal marine SAV habitats and find the common threads that tie these ecosystems together. Studies relating SAV habitats in the United States to a variety of factors are reviewed here, including geomorphological and bathymetric characteristics, sediment dynamics, sedimentological characteristics, and water quality, as well as hydrologic regime and weather. Tools and methods used to assess each of these important factors are also reviewed. A better understanding of fundamental environmental factors that control SAV growth will provide crucial information for coastal restoration and engineering project planning in areas populated by SAVs.