17 Aug 2026

Habitat Classification of the St. Marys River Near the Soo Locks, Michigan

Abstract: In June and October 2019, the US Army Corps of Engineers, Detroit District, collected over 130 linear miles (215+ km) of side-scan sonar data on the St. Marys River—from the northern lock region to the Lower Little Rapids—to map benthic habitats. In 2020, 56 bottom samples and 24 remotely operated vehicle (ROV) videos were collected to validate the sonar data. Although mapping the same regions twice to assess seasonal variability was mostly unachievable due to environmental and operational factors, four regions were successfully repeated. Crucially, the dataset includes the newly restored Little Rapids and a previously unmapped area downstream of the main rapids. Results revealed abundant submerged aquatic vegetation across the St. Marys River, likely driven by a highly variable sediment matrix ranging from clay to boulders. These data will be invaluable for planning and assessing habitat diversity and health in this vital ecological system.

12 Aug 2026

Introduction of Three Cryptic Lineages of Invasive Crested Floating Heart (Nymphoides cristata) in the Southeastern United States

Abstract: Crested floating heart [Nymphoides cristata (Roxb.) Kuntze] is an invasive aquatic plant in the southeastern United States. For clonal plants like N. cristata, clonal diversity may influence response to control tactics and/or evolutionary potential. However, little is known about the diversity of introduced N. cristata. In this study, we used genotyping by sequencing to quantify N. cristata diversity in the southeastern United States and determine how that diversity is distributed across the invaded range. Our results show that at least three distinct genetic lineages of N. cristata are present in the southeastern United States. Geographic distribution of the lineages varied, with one widespread lineage identified across several states and others only found in a single water body. There is also evidence of extensive asexual reproduction, with invaded water bodies often host to a single genetic lineage. The genetic diversity reported in this study likely results from multiple introductions of N. cristata to the southeastern United States and should be considered by managers when assessing control tactics, such as screening for biocontrol agents or herbicide testing. The extent and distribution of genetic diversity should also be considered by researchers studying the potential for invasive spread of N. cristata within the United States or hybridization with native Nymphoides species.

11 Aug 2026

Establishing Native Submersed Aquatic Vegetation at Times Beach, Buffalo, New York

Purpose: Establishing native submersed aquatic vegetation (SAV) in reservoirs, lakes, and ponds involves several considerations, including sources and types of transplant propagules, fluctuating water levels, and herbivory (Smart et al. 1998). Over the past 20 years, US Army Engineer Research and Development Center (ERDC) Environmental Lab researchers have developed methods for establishing native SAV that address these issues. While consistently and successfully applied in the southern United States (Dick et al. 2005), their applicability to northern waterbodies remains untested. This two-part demonstration study evaluated several SAV establishment techniques in a constructed wetland adjacent to Lake Erie, Buffalo, New York.

4 Jun 2026

Efficacy of UVC Treatment on Hydrilla verticillata and Trapa spp.

Abstract: Hydrilla verticillata and Trapa spp. are invasive aquatic plants that pose serious challenges to freshwater ecosystems. In search of a nonchemical method to eradicate H. verticillata and Trapa spp., this study explores the application of UVC light to target the adult plant forms and the dormant turions of H. verticillata as well as the seedlings of Trapa spp. Contrary to our expectations, the experimental results demonstrated that UVC exposure had no significant effect on reducing the viability of either adult hydrilla plants or their turions. Despite treatment with a range of UVC doses, the plants remained viable and the turions were able to germinate successfully. UVC exposure did, however, cause a significant reduction in biomass for both Trapa species tested. These findings suggest that UVC light, at least under the conditions tested, is not an effective standalone strategy for controlling hydrilla but may be a useful nonchemical tool for controlling Trapa spp. Further research is required to explore alternative nonchemical methods or to refine the application parameters of UVC if it is to be further considered for eradication of these two invasive aquatic plants

10 Sep 2025

Light Availability Calculator for Identifying Suitable Habitat for Light-Limited Aquatic Vegetation

Purpose: The purpose of this Ecosystem Management and Restoration Research Program Technical Note (EMRRP TN) is to introduce a geospatial Light Availability Calculator, designed to inform suitable habitat selection for light-limited, submerged aquatic vegetation (SAV) species. The need and intended use for the Light Availability Calculator is first described. Then, the scientific and mathematical formulations underpinning the calculator are explained. Finally, recommendations for calculator inputs reflective of various user needs (simple and rapid versus complex and time intensive) are described.

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.

9 Jun 2025

Review of Remote-Sensing Methods for Mapping Riparian and Submerged Aquatic Vegetation: Support for Ecosystem Restoration Monitoring and Flood Risk Management

Abstract: Riparian vegetation, defined as multilayered herbaceous and woody plant communities along river margins or bank edges, and freshwater submerged aquatic vegetation (SAV), described as rooted aquatic plants in shallow rivers, lakes, and estuaries, are key factors influencing the connection between river and floodplain systems. These vegetation types are often used as indicators of riparian health. Current data on riparian vegetation and SAV are essential for addressing future water resource needs, particularly for restoration monitoring and flood risk management. The US Army Corps of Engineers (USACE), as the federal government’s largest water resources development and management agency, requires updated monitoring and assessment methods to support the development, utilization, and conservation of water and related resources. Assessing large riparian corridors involves characterizing baseline conditions, habitat extents, vegetation patterns, and health. Vegetation and habitat data are critical for evaluating the effects of project operations, resource management, and restoration outcomes downstream from USACE dams. However, obtaining such data across large, dynamic, and inaccessible river reaches is challenging. Integrating field-based techniques with remote-sensing technology offers opportunities to map larger areas comprehensively and adapt to future water resource needs. This report reviews re-mote sensing methods for mapping riparian and SAV habitats with emphasis on vegetation characteristics.

4 Apr 2025

Field Evaluations of Diquat for Controlling Submersed Flowering Rush in Lake Pend Oreille, Idaho

Abstract: The invasive plant flowering rush (Butomus umbellatus L.) was first observed in Lake Pend Oreille, Idaho, within the Columbia River basin in 2008, and it covered several hundred hectares by 2016. Dense infestations of this perennial weed destroy native plant communities and seriously degrade fish and wildlife habitat. Sometimes growing as an emergent on saturated soils or in shallow water, the plant also forms persistent submersed stands in deeper water, which is the typical growth form in Lake Pend Oreille. In 2016, field trials evaluated the herbicide diquat dibromide, formulated as the product Reward, for controlling submersed flowering rush. A 4 ha plot in Oden Bay was treated with diquat at a rate of 18.7 L/ha in late summer 2016 and again in 2017 using a subsurface injection method by boat. Water exchange processes were measured in treated plots in 2017 with rhodamine WT dye mixed with the herbicide. Flowering rush shoots were reduced by 87% in 2016 and 29% in 2017. No adverse effects were measured on water quality (temperature, dissolved oxygen, pH, and conductivity). Diquat should be added to the project’s operational management strategy for controlling flowering rush in Lake Pend Oreille.

4 Feb 2025

Beneficial Use of Dredged Material for Submerged Aquatic Vegetation Habitats: Overcoming Challenges and Seeking New Opportunities

Purpose: There is a critical need to maintain and create conditions that are conducive for long-term survival of submerged aquatic vegetation (SAV) habitats, which provide multiple ecosystem services, using dredged material. This technical note (TN) was developed by the US Army Engineer Research and Development Center (ERDC)–Environmental Laboratory (EL) to address the specific challenges US Army Corps of Engineers (USACE) practitioners at the district and division level face that impede the development of beneficial use of dredged material (BUDM) projects to restore, conserve, and expand SAV habitats. Different ways to overcome these challenges and opportunities that should be further explored are also addressed. The information in this TN was synthesized from discussions at a virtual workshop for USACE practitioners.

15 Oct 2024

Vegetation Establishment and Management in USACE Floodwater Detention Basins: Greens Bayou Flood Risk Management Mitigation Project

Abstract: This report documents efforts by the US Army Engineer Research and Development Center (ERDC) in assisting the US Army Corps of Engineers (USACE) Galveston District (SWG) in native vegetation establishment design, propagation, installation, monitoring, and adap-tive management for the mitigation requirements of the Greens Bayou Flood Risk Management Project. Specifically, to provide (1) a vegetation establishment design ensuring development of sustainable native plant communities compatible with flooding and drought events; (2) suitable native aquatic, wetland, and woody plants for project use; (3) implementation of plantings; (4) monitoring and adaptive management; and (5) vegetation establishment reports and an operations and maintenance manual for long-term vegetation management of the project site. The Greens Bayou Project included approximately 3.7 miles of channel conveyance improvements and 138 acres of storm-water basin detention storage to reduce flooding damage by safely storing excess stormwater during heavy rain events and slowly releasing it back into the bayou. The completed basin was designed to hold approximately 1,400 acre-ft, or 538 million gal., of stormwater. Vegetation establishment, monitoring, and adaptive management efforts in the mitigation features discussed herein occurred between 2019 and 2023.