7 Oct 2025

Gravel Investigations Informing Resource Management Within the Lower Mississippi River

Abstract: This report integrates available information about gravel deposits within the Lower Mississippi River (LMR) from previous studies coupled with new analysis to identify reoccurring observed gravel locations. This study also summarizes spatial and temporal trends of bed material sediment characteristics, focusing primarily on gravel. Moreover, selected data sets from previous studies, and field and aerial observations have been added to a geographic information system (GIS) database housed in ArcPro to illustrate observed gravel locations. Last, a literature review documenting the ecological importance of gravel bars to riverine fauna and a brief discussion of potential technologies to support conservation efforts are included. Major findings summarized herein are (1) the presence of gravel deposits tend to decrease in a downstream direction along the LMR; (2) qualitative analyses of aerial videos suggest that gravel-predominant bars are more common between River Miles 953 and 681; (3) past investigations have documented gravel sizes at rivers bars ranging from pebbles to boulders; (4) the gravel content in LMR bed material samples has decreased since 1932; and (5) more detailed surveys are needed to better delineate the spatial extents and depth of gravel bars and identify suitable technology to detect potential buried gravel.

27 Aug 2025

Evaluating Transport of Stockpiled Mississippi River System Sand for Beach Nourishment and Other Uses

The US Army Corps of Engineers (USACE), Rock Island and St. Paul Districts, maintain 876 miles of shallow-draft navigation channels, dredging approximately 2 million cubic yards of clean, fine- to medium-grained sands from these waterways annually. Due to system constraints and certain state regulatory policies, most of this dredged material (DM) is placed in upland and island facilities. As these dredge placement areas fill with sediment, the districts need to remove sediment to create additional storage or seek new land acquisition. While a significant amount of this DM is being locally used beneficially, the current uses are opportunity driven and dictated by proximity. As such, the districts continue to seek alternative beneficial use practices. One major limiting factor to increased beneficial use is the cost of material transport. Per the Federal Standard, USACE will use the least costly DM placement alternatives that are consistent with sound engineering practices and meet federal environmental requirements. Transport beyond traditional placement sites typically costs much more. The analysis described in this report reviews nontraditional transportation modes and routes to match distant needs with river sediment.

21 Apr 2025

Potential Benefits of Subaqueous Soil Data on Department of Defense Installations

Purpose: Many domestic and international US Department of Defense (DoD) installations are located in coastal areas. Recent advances in the classification and mapping of subaqueous soils, which occur in shallow freshwater and marine environments, has the potential to benefit US military operations in several different ways. This technical note communicates the importance of subaqueous soil classification and describes how subaqueous soil information can inform the management of natural resources, infrastructure and transportation, mitigation of coastal storm risk, protection of the coast from natural threats, and the understanding of nearshore environments in the US and abroad.

25 Aug 2020

PUBLICATION NOTICE: Fine-Grained Sediment within Olcott Harbor, Eighteenmile Creek, NY

Abstract: Olcott Harbor, located at the mouth of Eighteenmile Creek and Lake Ontario, and a Great Lake Area of Concern, provides a temporary sink for contaminated, fine-grained sediment transported downstream from the Superfund site near Lockport, NY. The volume of fine-grained sediment currently stored in Olcott Harbor and Eighteenmile Creek is unknown, complicating remediation efforts. The US Army Corps of Engineers (USACE), Buffalo District (LRB), has partnered with the New York State Department of Environmental Conservation to address the mitigation of contaminated sediment accumulating within Eighteenmile Creek. As part of this effort, researchers from the US Army Engineer Research and Development Center (ERDC) collaborated with LRB to delineate fine-grained sediment regions from coarse-grained regions in Olcott Harbor and Eighteenmile Creek via a geophysical survey in July 2017. Where possible, ERDC also estimated the thickness of the fine-grained sediment areas to determine overall fine-sediment volume. Sidescan sonar was used to map the surface transition from the coarser-grained sediment in the outer harbor to the finer-grained sediment in the inner harbor. Chirp sub-bottom profiles successfully imaged the subsurface transition from coarse- to fine-grained sediment in some areas but provided only limited thickness data. This technical note summarizes the field effort, data processing, and final interpretations.

20 Aug 2020

PUBLICATION NOTICE: Sediment Sorting by Hopper Dredging and Pump-Out Operations: Sampling Methods and Analysis

Abstract: Hopper dredging operations for beach and nearshore placement typically include periods of overflow, which produces some degree of separation between the size fractions of the dredged sediment. The degree of separation and the controlling factors are presently poorly known. This report focuses on laboratory experiments aimed at determining (1) suitable sampling methods on a dredge, (2) composite sampling techniques to reduce analysis cost, (3) associated sampling intervals to achieve suitable sediment representation of a hopper load, and (4) a hydraulic means of sample splitting. Results showed that no statistical difference exists among the three methods used to sample the hopper weir overflow. The method used to sample deposited hopper sediment identified a bias in the percent fines that resulted from flow sheltering. Further, it was found that composited samples were able to quantify the concentration and percent fines accurately, although an analytical data experiment showed that the accuracy of a composited sample is dependent on the sampling intervals. The accuracy of the fines and concentration from a hydraulic sample splitter was found to be dependent on median grain size, with fine sediment being evenly distributed and coarser sediment increasing the error in concentration and grain size distribution.

25 Jun 2020

PUBLICATION NOTICE: Characterization of eroded mud aggregates with the Flume Imaging Camera System (FICS) and its added value to sediment management projects

Abstract: The goal of this technical note (TN) is to describe the functionality and added research value of the Flume Imaging Camera System (FICS), a US Army Engineer Research and Development Center (ERDC)-developed system designed to measure the size of sediment particles immediately following erosion.