8 Dec 2025

Assessing Fish-Passage Rates

Abstract: Riverine fragmentation by dams, culverts, and other barriers has led to the precipitous decline of migratory fishes nationwide. Accordingly, fish-passage restoration has emerged as a significant issue for resource agencies, restoration professionals, and fisheries managers. This special report addresses the key scientific challenge of measuring fish-passage rates before and after restoration. A variety of techniques for both forecasting (preproject) and monitoring (postproject) fish-passage rates are reviewed. A set of guiding questions are presented to help practitioners select a method appropriate to their site, resources, and time line. Four case studies are then presented to demonstrate a subset of these methods in practice: fish community movement through floodgate structures in Missouri, movement patterns through river restoration structures in Colorado, fish movement around a low-head weir in Mississippi, and watershed-wide passability estimation using professional judgment in Nevada. These projects represent a range of conditions and are intended to provide practitioners with real-world examples to use as models for their own studies.

8 Dec 2025

Modeling Tools for Proactive Ecosystem Restoration and Assisted Migration Planning: A State of the Science Review and Synthesis

Abstract: Decision-support modeling tools are needed to help aquatic ecosystem restoration (AER) planners understand how habitat footprints and species distributions will change in response to future changing conditions. Specifically, environmental projections and predictive model outputs that inform proactive AER planning and investments. This report provides a literature synthesis of resources and tools to create such a decision support tool. Select models identified were evaluated for applicability to AER planning using prediction confidence, user-friendliness, and suitability. This uncovered several existing, primarily terrestrially, predictive models that could be adapted to inform proactive AER planning efforts. Research efforts are still needed to fill gaps for aquatic data to train and validate predictive models, refine key drivers, and build and pilot aquatic-focused tools. Future condition vulnerability screening tools could be used to identify which proposed AER project sites are best suited for proactive AER measures, such as assisted migration, and determine if investments in more rigorous, spatially explicit, or species-specific models are needed. Species-specific assessments of habitat suitability changes and adaptive capacity can then inform restoration targets and enable end-users to achieve AER planning objectives. Such a decision support tool would improve planner ability to restore key aquatic habitats resilient to future conditions.

8 Dec 2025

The Trajectory of Iron Sulfide Oxidation and Production in Marshes Created from Dredged Sediments at Poplar Island: Implications for Wetland Plant Establishment

Abstract: The following report provides a summary of the effects of iron sulfide dynamics (e.g., oxidation and formation) on the establishment of plant communities in wetlands created from fine-grained dredged sediments at Poplar Island in Maryland’s mid-Chesapeake Bay. The challenges associated with handling sulfide-rich sediments are discussed using examples from dredged channels and subsequent placement in a created wetland setting in the upper Chesapeake Bay. Information is synthesized from multiple previous peer-reviewed publications as well as unpublished studies, all conducted by the Horn Point Laboratory (University of Maryland, Center for Environmental Science), on the trajectory of sulfur constituents in Poplar Island created wetlands. The implications for vegetation trajectories are discussed and the knowledge base of sulfide mineral biogeochemistry in managed coastal wetland systems is expanded.

29 Aug 2025

Monitoring of Understudied Wetlands: State of Knowledge

Abstract: Some wetlands can present unique challenges for mapping and monitoring due to their size, location, foliage architecture, and spectral characteristics. For instance, assessing ecological condition and restoration success using traditional remote-sensing systems in forested and ephemeral wetlands is onerous. Therefore, the purpose of this technical note is to evaluate the state of knowledge and technology related to the use of remote sensing in assessing vegetation dynamics in understudied and hard to monitor wetlands. Ultimately, this exercise will identify data gaps and recommend improvements for analyzing and modeling wetland systems and trends, quantifying disturbance impacts, and assist efficiencies of data collection to improve management decisions, which in turn will help in reaching restoration goals.

20 Aug 2025

Trade-offs Between Field and Remote Geomorphic Monitoring of Coastal Marsh Restoration Sites

Abstract: Coastal marsh restoration presents geomorphic monitoring challenges because these sites are often remote or inaccessible, and time and financial resources for field data may be limited. Yet, elevation and shoreline characteristics contribute to the overall health and longevity of coastal marshes. The expansion of Uncrewed Aircraft System (UAS) technology and new satellite platforms offer opportunities to complement ground-based geomorphic monitoring and overcome the challenges of traditional field methods. Here, we compare field-based and remote-sensing approaches to monitor two restored coastal wetlands in Louisiana. At Spanish Pass, methods for measuring site elevation, shoreline position, and shoreline geomorphic types were compared. Ground surveys strongly correlated with UAS-lidar digital elevation model (DEM) elevations (R2 = 0.97. UAS and satellite imagery were accurate to within 3 meters of field-shoreline positions, and UAS-lidar-derived shorelines had the lowest error. At LaBranche, UAS-lidar DEM data were paired with airborne lidar and legacy ground surveys to track temporal changes in elevation, indicating minimal elevation change. The study demonstrates the accuracy and utility of satellite and UAS remote sensing for monitoring shoreline positions and elevations but notes that shoreline classifications could be improved with additional quantification. These findings help practitioners assess the trade-offs and benefits of various monitoring methods.

29 Jul 2025

Engineering Practice Guide for Floodplain Benching: A Natural Infrastructure Approach for Riverine Systems

Abstract: Floodplain benches are a potential solution for inland river systems where out-of-bank flooding generates unacceptable flood risk and access to riverine floodplains has become restricted over time. Benches are a naturally forming geomorphic feature between the riverbed and a higher floodplain or terrace. In addition to reducing flood risk, benches reduce erosion risk, improve aquatic ecosystems, enhance plant and wildlife diversity, expand recreational opportunities, and may be places of cultural and tribal value. This document informs engineering activities related to site investigation and design of floodplain benches. It is intended to be used by engineers and ecologists to inform the design of floodplain benches in a manner that is consistent with and augments other planning, design, and engineering guidance. A well-designed floodplain bench can improve ecological and biological functions while also reducing flood risk by creating a channel in geomorphic equilibrium with current conditions and resilience to anticipated changes in hydrology and sediment supply rates. This publication is among a series of planned technical reports providing guidance on how to identify, conceptualize, and design natural infrastructure solutions for riverine and coastal systems. It has been produced by the US Army Corps of Engineers (USACE) Engineering With Nature® Program.

14 Jul 2025

Submerged Aquatic Vegetation Monitoring for Process-Based Model Development

Purpose: Submerged aquatic vegetation (SAV) habitat conservation and restoration are necessary actions to counteract the loss of these critical habitats and their associated ecosystem services, such as habitat provisioning and water quality improvements. Process-based numerical models are essential for planning effective and enduring SAV management strategies but require robust datasets to realistically represent processes at high spatial and temporal resolutions. This technical note (TN), developed by the US Army Engineer Research and Development Center–Environmental Laboratory (ERDC-EL), describes an SAV data collection framework that is being applied at freshwater pond mesocosms to better capture intra-annual SAV growth and mortality processes needed to parameterize process-based models.

11 Jul 2025

Lower Mississippi River Resource Assessment: Library of Aquatic Habitat Models

Abstract: Six ecosystem models were developed to evaluate restoration measures for the Lower Mississippi River Resource Assessment that considered connectivity between river and floodplain, substrate quality in riverine habitats, and targeted species of special interest including Paddlefish and wetland fish assemblages. A total of 85 restoration measures in the Hatchie to Loosahatchie reach were identified by the Project Delivery Team that had different modeling requirements. Field data collected by the Engineer Research and Development Center–Environmental Laboratory in the Lower Mississippi River and floodplain identified ecological guilds of fish and aquatic invertebrates representative of different fluvial habitats. Regression and frequency bar chart models developed from this database predicts a biotic response as a function of habitat quality. Six models applicable to either riverine (unidirectional flow) or floodplain (bidirectional flow) environments were used to evaluate measures for enhancing benthic substrates, reestablishing woody debris, and formation of eddies to diversify habitat. Outputs were normalized as a Habitat Suitability Index on a 0–1 scale and a spreadsheet developed to calculate and annualize Habitat Units for selected restoration measures. Models were certified by US Army Corps of Engineers National Ecosystem Restoration Planning Center of Expertise for regional use in the Lower Mississippi River.

4 Jun 2025

Developing an Ecosystem Goods and Services Assessment Framework: Products and Resources

Purpose: The Environmental Research Area Review Group has long recognized a need to understand the role of Ecosystem Goods and Services (EGS) in US Army Corps of Engineers (USACE) civil works planning. An EGS Work Unit, funded by the Ecosystem Management and Restoration Research Program (EMRRP), has collaborated for more than a decade to develop many products and resources useful to USACE planners and policy makers. This technical note reviews the body of work produced by this large, diverse, and dedicated team.

6 May 2025

Technical Recommendations for the Identification and Management of Potential Acid Sulfate Soils in an Ecological Restoration Context

Abstract: Restoration projects are being implemented to address natural and anthropogenic threats to coastal wetlands, including increased inundation and historic land use alterations. The US Army Corps of Engineers (USACE) and other organizations introduce dredged sediments into coastal environments to increase elevation and stabilize marsh platforms. However, some dredged sediments either contain iron sulfide compounds (i.e., iron monosulfide [FeS] and pyrite [FeS₂]) or form them after application. Under aerobic conditions, FeS and FeS₂ can rapidly oxidize, which generates acidity that can dramatically lower the soil pH, impacts plant establishment, and threatens the success of wetland restoration projects. Recommendations are needed to properly manage iron sulfide containing materials through project design, screening, monitoring, and adaptive management. Tools and techniques exist to evaluate dredged sediments for the presence of FeS and FeS₂ prior to and following marsh sediment applications, and project design and construction approaches can minimize associated acidification risks. This report provides a framework for properly identifying and managing sediments containing iron sulfide minerals during wetland restoration projects. These technical recommendations provide dredged sediment beneficial use practitioners a decision support tool for the successful management of iron sulfide containing dredged sediments to increase the ecological function and sustainability of coastal wetlands.