5 Oct 2023

Review of Riparian Models for Assessing Ecological Impacts and Benefits

BACKGROUND: Riparian zones are key transitional ecosystems between upland and aquatic zones, and these systems are often degraded due to both land use change and stream processes (e.g., deforestation and water impoundments and/or diversions). These important ecosystems require restoration because of the many benefits they provide ranging from providing habitat for diverse species to promoting water quality. Restoration practitioners, regulators, and researchers require riparian assessment methods and models to efficiently guide mitigation and restoration planning. This technical note (TN) compiles a subset of existing riparian tools and evaluates them relative to model objectives, modeling approach, and input variables. Findings are synthesized into a gap analysis of these models to inform future riparian model development and improve riparian assessment.

25 Sep 2023

Defining Levels of Effort for Ecological Models

BACKGROUND: While models are useful tools for decision-making in environmental management, the question arises about the level of effort required to develop an effective model for a given application. In some cases, it is unclear whether more analysis would lead to choosing a better course of action. This technical note (TN) examines the role of ecological model complexity in ecosystem management. First, model complexity is examined through the lens of risk informed planning. Second, a framework is presented for categorizing five different levels of effort that range from conceptual models to detailed predictive tools. This framework is proposed to enhance communication and provide consistency in ecological modeling applications. Third, the level of effort framework is applied to a set of models in the Middle Rio Grande River system to demonstrate the framework’s utility and application. Ultimately, this TN seeks to guide planners in determining an appropriate level of effort relative to risks associated with uncertainty and resource availability for a given application.

15 Sep 2023

Real-Time Forecasting Model Development Work Plan

Abstract: The objective of the Lowermost Mississippi River Management Program is to move the nation toward more holistic management of the lower reaches of the Mississippi River through the development and use of a science-based decision-making framework. There has been substantial investment in the last decade to develop multidimensional numerical models to evaluate the Lowermost Mississippi River (LMMR) hydrodynamics, sediment transport, and salinity dynamics. The focus of this work plan is to leverage the existing scientific knowledge and models to improve holistic management of the LMMR. Specifically, this work plan proposes the development of a real-time forecasting (RTF) system for water, sediment, and selected nutrients in the LMMR. The RTF system will help inform and guide the decision-making process for operating flood-control and sediment-diversion structures. This work plan describes the primary components of the RTF system and their interactions. The work plan includes descriptions of the existing tools and numerical models that could be leveraged to develop this system together with a brief inventory of existing real-time data that could be used to validate the RTF system. A description of the tasks that would be required to develop and set up the RTF system is included together with an associated timeline.

5 Sep 2023

Aquatic Ecosystem Restoration in the Texas Western Gulf Coast Plain / Lower Rio Grande Alluvial Floodplain Ecoregion: Resaca Boulevard Resaca Section 206—Vegetation Community Adaptive Management

Abstract: As part of the US Army Corps of Engineers (USACE) Continuing Authorities Program (CAP), Section 206 projects focus on restoring aquatic habitats for the benefit of fish and other wildlife. From 2017–2021, USACE Engineer Research and Development Center–Environmental Laboratory researchers in the Aquatic Ecology and Invasive Species Branch (ERDC-EL EEA) at the Lewisville Aquatic Ecosystem Research Facility (LAERF) collaborated with USACE Galveston District, The Nature Conservancy, US Fish and Wildlife Service, National Park Service, and local nonfederal sponsors—Brownsville (Texas) Public Utility Board and the City of Brownsville—to study restoration methods on former, naturally cut-off, channels of the Lower Rio Grande River. These aquatic ecosystems, locally termed “resacas,” are home to endemic plants and animals and are thus an important natural resource of national interest. This technical report documents the planning, design, construction, monitoring, and adaptive management activities throughout the Resaca Boulevard Resaca Section 206 Aquatic Ecosystem Restoration project. Methods and results for invasive species management—primarily Brazilian peppertree (Schinus terebinthfolia)—and aquatic and riparian vegetation establishment in endemic Texas ebony resaca forest, subtropical Texas palmetto woodland, and Texas ebony/snake-eyes shrubland habitats are discussed.

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.

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.

6 Apr 2023

Eelgrass Functions, Services, and Considerations for Compensatory Mitigation

Abstract: Coastal-marine eelgrass habitat is a critical resource within New England and throughout the world. Eelgrass habitat provides functions and services including providing structure, biogeochemical cycling, erosion reduction, habitation provision, and water quality improvement. Declines in eelgrass distribution are often due to anthropogenic processes impacting temperature and water quality. Declines in distribution and abundance highlight the importance of protecting the existing eelgrass, improving environmental conditions allowing for ecosystem restoration, and identifying viable in-kind and out-of-kind compensatory mitigation measures. Considering the limited availability of New England sites for in-kind compensatory mitigation, additional approaches for out-of-kind compensatory mitigation should be considered. These include (1) creation of alternative plant or kelp habitat, (2) using a multi-pronged, multi-habitat and structure approach, (3) contributing to the development of water quality improvement initiatives to encourage current eelgrass bed expansion over time, (4) reduce physical impacts to eelgrass habitat, (5) and identifying locations for future eelgrass habitat suitability based on climate predictions and investing to create future compensatory mitigation habitat in these locations.

6 Oct 2022

Incorporating Social and Environmental Outputs in Decision-Making: Workshop Outcomes

PURPOSE: This document summarizes the notable outcomes of the workshop “Quantifying and Incorporating Social and Environmental Outputs in Decision-Making—Research and Development Needs and Strategy Workshop.” The workshop was held 24 and 25 July 2019 in Alexandria, Virginia, at the US Army Corps of Engineers’ (USACE) Institute for Water Resources (IWR). The workshop sought to identify gaps in knowledge, methods, data, and tools and to identify types of subject matter experts who would be needed for the research team. A total of 22 participants attended the facilitated workshop, representing a broad array of expertise: economists, scientists, planners, social scientists, project managers, and researchers from a number of USACE organizations and partnering academics across the United States. Together, these attendees reviewed existing policy and research and prioritized future work to fill gaps in methods and procedures for incorporating social and environmental inputs across a broad range of USACE projects.

29 Sep 2022

Birds of the Craney Island Dredged Material Management Area, Portsmouth, Virginia, 2008-2020

Abstract: This report presents the results of a long-term trend analyses of seasonal bird community data from a monitoring effort conducted on the Craney Island Dredged Material Management Area (CIDMMA) from 2008 to 2020, Portsmouth, VA. The USACE Richmond District collaborated with the College of William and Mary and the Coastal Virginia Wildlife Observatory, Waterbird Team, to conduct year-round semimonthly area counts of the CIDMMA to examine species presence and population changes overtime. This effort provides information on the importance of the area to numerous bird species and bird species’ groups and provides an index to those species and group showing significant changes in populations during the monitoring period. We identified those species regionally identified as Highest, High, and Moderate Priority Species based on their status as rare, sensitive, or in need of conservation attention as identified by the Atlantic Coast Joint Venture (ACJV), Bird Conservation Region (BCR), New England/Mid-Atlantic Bird Conservation Area (BCR 30). Of 134 ranked priority species in the region, the CIDMMA supported 102 of 134 (76%) recognized in the BCR, including 16 of 19 (84%) of Highest priority ranked species, 47 of 60 (78.3%) of High priority species, and 39 of 55 (71%) of Moderate priority species for BCR 30. All bird count and species richness data collected were fitted to a negative binomial (mean abundance) or Poisson distribution (mean species richness) and a total of 271 species and over 1.5 million birds were detected during the monitoring period. Most all bird species and species groups showed stable or increasing trends during the monitoring period. These results indicate that the CIDMMA is an important site that supports numerous avian species of local and regional conservation concern throughout the year.

23 Sep 2022

Literature Review: Macrohabitat Metrics to Identify Presence of Chiroptera on the Landscape in the United States

Abstract: This special report reviews current scientific literature to identify the most commonly cited metrics used to describe the macrohabitat criteria important for Chiroptera presence in the United States. The review evaluates 69 scientific articles from 1994 to 2018. The most commonly cited metrics were divided into four main categories: tree-species-level metrics, landscape-level metrics, distance metrics, and topographic and atmospheric metrics. Of all metrics found, the top six most common metrics noted across all articles were percent canopy cover, diameter at breast height (DBH), forest type, distance to water, distance to roads or other urban features, and tree density. In addition, 27 of the 47 (57%) bat species located within the United States were represented. These metrics provide important insight into the regional or national species-level distribution and assist with modeling the relationship between species distribution and habitat change.