25 Sep 2025

Effects of Suspended Sediment on Aquatic Organisms: A Literature Review and Database Effort

Abstract: The US Army Corps of Engineers (USACE) acknowledges that uncertainties and public perceptions regarding the effects of suspended sediment on aquatic organisms, particularly the concentration thresholds associated with harmful effects, present an ongoing challenge to its dredging mission. USACE is actively working to address these challenges through improved monitoring, research, and collaboration to support safer and more sustainable dredging practices. To help mitigate this uncertainty, 159 field- and laboratory-based studies describing the effects of sediment on aquatic organisms were reviewed and compiled in a database. No- and low-effect ecotoxicity data from this review were further analyzed to determine percentiles of effects data and species sensitivity distributions. The analysis indicated corals and freshwater crustaceans were most sensitive, followed by fish, while bivalves and marine crustaceans appeared to be the most tolerant of suspended sediment. This literature review provides a foundational framework for visualizing site-specific suspended sediment thresholds for effects concentrations associated with potential effects on aquatic species. It serves as a starting point for identifying critical data gaps for future research, layering in additional data, refining thresholds, and supporting more informed, site-specific decision-making moving forward.

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.

1 Dec 2020

Formulation of a Multi-Scale Watershed Ecological Model Using a Statistical Approach

Abstract: The purpose of this special report is to provide a statistical stepwise process for formulation of ecological models for application at multiple scales using a stream condition index (SCI). Given the global variability of aquatic ecosystems, this guidance is for broad application and may require modification to suit specific watersheds or stream reaches. However, the general statistical treatise provided herein applies across physiographies and at multiple scales. The Duck River Watershed Assessment in Tennessee was used, in part, to develop and test this multiscale, statistical approach; thus, it is considered a case example and referenced throughout this report. The findings of this study can be utilized to (1) prioritize water-sheds for restoration, enhancement, and conservation; (2) plan and conduct site-specific, intensive ecosystem studies; and (3) assess ecosystem outcomes (that is, ecological lift) applicable to future with and without restoration actions including alternative, feasibility, and cost-benefit analyses and adaptive management.