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.