24 Sep 2020

South Atlantic Division (SAD) Regional Sediment Management Optimization Pilot

Purpose: The US Army Corps of Engineers (USACE) South Atlantic Division (SAD) Regional Sediment Management Optimization Pilot (RSM-OP) Tool was developed and implemented under a pilot effort to help define sustainable solutions across USACE missions and to support regional implementation strategies across project business lines. The goals of the RSM-OP are to (1) develop and provide an actionable and optimized Regional Sediment Management (RSM) strategy on a USACE division scale that will most efficiently execute the Navigation (NAV) and Flood Risk Management (FRM) Business Line budgets and (2) maximize the amount of dredging while also increasing the amount of RSM opportunities implemented to create value to the nation. Value created and funding saved as identified through the RSM-OP will allow the USACE to execute a greater number of projects under flatlined or reduced budgets. While RSM principles and strategies have been explored and implemented in many USACE districts, the RSM-OP is the first comprehensive approach to define and optimize RSM opportunities for coastal NAV and FRM projects and to quantify economic benefits across a USACE division.

1 Sep 2020

PUBLICATION NOTICE: Contribution of Two Eroding Banks to Multipurpose Pool Sedimentation at a Midwestern Reservoir

Abstract: This US Army Corps of Engineers (USACE) National Regional Sediment Management Technical Note (RSM-TN) documents the sediment contribution of two eroding banks to multipurpose pool sedimentation at Kanopolis Lake, KS. The analysis is based on a 2009 LIDAR and an August 2019 unmanned aircraft systems (UAS)-based structure from motion survey.

25 Aug 2020

PUBLICATION NOTICE: New York/New Jersey Harbor Sedimentation Study: Numerical Modeling of Hydrodynamics and Sediment Transport

Abstract: The New York/New Jersey Harbor (NYNJH) is a vital economic resource for both the local economy and the entire US economy due to the vast quantity of imports and exports handled by the numerous ports in this waterway. As with most ports, there is a significant, recurring expense associated with dredging the navigation channels to the authorized depths. In an effort to determine the impact of channel enlargements (“the project”) on dredging volumes, a numerical model study was performed. The advantage of a numerical model study is the ability to isolate individual system modifications and associated impacts in terms of dredging volumes. Five years (1985, 1995, 1996, 2011, and 2012) were simulated for both the with- and without-project conditions to determine the impact of the channel deepening on the dredging requirements for a wide range of meteorological conditions including storm events. The numerical model results were analyzed to provide insight into which locations will experience increased/decreased deposition and quantify the amount of increase/decrease for a given channel reach. The model results indicate a relatively minor increase in the total dredge volumes for the NYNJH with the increase being insignificant in comparison to the natural variability in dredge volumes across years.

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.

30 Jul 2020

PUBLICATION NOTICE: Investigation of Shoaling in the Federal Navigation Channel, Waukegan Harbor, Illinois

Abstract: Persistent and excessive shoaling occurs in the Outer Harbor and Approach Channel of the Waukegan Harbor, Illinois. This report describes a numerical modeling study performed for the US Army Corps of Engineers, Chicago District, to evaluate the existing harbor and 11 structural alternatives for three crest elevations. This report provides details of numerical modeling study, analysis of field data, and estimates of shoaling. The focus of the study is the investigation of a variety of structural solutions intercepting and/or diverting sediments to reduce shoaling in the navigation channel. These include breakwaters, groins, spurs, and structural extensions with varying length and crest elevation connecting to the north beach and existing north breakwater. Estimates of both shoaling volume and height are developed with and without project using an integrated wave-flow-sediment transport numerical modeling approach. Quantitative reduction estimates are provided for each structural alternative investigated.

9 Jul 2020

PUBLICATION NOTICE: Hydrodynamics of a Recently Restored Coastal Wetland: Hamilton Wetlands, California

Abstract: Hamilton Wetlands is a recently restored tidally influenced basin located along the northwest coast of San Pablo Bay, California. Instruments to measure waves, currents, and wind were deployed for a period of up to 2 years shortly after tidal flow was re-introduced to the wetland to examine the sediment and hydrodynamic response. The results indicate that local re-suspension is relatively rare owing to the weak interior tidal currents and the limited fetch within the 3 km long basin. Asymmetries in the acoustic backscatter intensity combined with the much higher flow speeds measured at the entrance suggest a net import of fine sediment. The basin also experiences a distinct seasonal variation that likely contributes to sediment re-distribution. During the summer months, higher wind speeds correlate with turbidity suggesting local re-suspension of fines that are distributed by winds. Overall, the measurements suggest that the sediment dynamics in this shallow water system are controlled by two main factors: (1) net sediment import through the inlet entrance and (2) mixing of interior sediment through a combination of intermittent wind and wave stirring.

17 Jun 2020

PUBLICATION NOTICE: Sediment Sorting by Hopper Dredging and Pump-Out Operations: Conceptual Model and Literature Review

Abstract: Dredged sediment placed on beaches or nearshore environments is customarily evaluated for compatibility with the native beach sediment to avoid unintended impacts to economic, environmental, or recreational resources. Consequently, some state regulatory authorities establish limits upon the fine-grained content for sediment designated for placement on certain beaches and nearshore environments. Hopper dredging operations for beach and nearshore placement typically include periods of overflow, which is recognized to produce some degree of separation between the size fractions of the dredged sediment. The degree of separation and the controlling factors of separation are presently poorly known and are the subject of this research. This report provides a conceptual model of the hopper dredging and placement processes, including the relevant processes associated with hopper dredge-associated sediment dynamics, generation and transport of the overflow sediment plume, and sediment winnowing at the beach outflow. Prior research is described, and knowledge gaps are identified. Finally, a research plan to validate prior research and to address knowledge gaps is presented. An annotated bibliography of relevant literature is given in an appendix. Documentation of the planned research presented herein will appear in future publications associated with this study.

10 Jun 2020

PUBLICATION NOTICE: Nearshore Placement Workshop 2019: Sediment Nourishment of the Nearshore Environment

Abstract: The Coastal Inlets Research Program and the Regional Sediment Management Program co-sponsored the 2019 Nearshore Placement Workshop. Thirty-four participants from the US Army Engineer Research and Development Center (ERDC) and numerous districts met in Vicksburg on January 29–30, 2019, as a part of the workshop. This workshop was convened to facilitate discussions on concerns districts face regarding nearshore placements from resource agencies and stakeholders, challenges to placing sediment in the nearshore, and future research needs. The workshop included ERDC presentations on the state of the science regarding nearshore placements; specific implementations of nearshore placements within various US Army Corps of Engineers districts; break-out-style discussions on nearshore placement challenges and potential paths forward; and group discussions on metrics for success, quantification of benefits, Statements of Need (SON), and research priorities. A few of the major recurring themes throughout the workshop were the importance of monitoring, concerns over the fate of fine-grained sediment, and difficulties conveying the benefits of nearshore placements to a wide range of audiences. The workshop culminated in a discussion of possible SON to be put forth to the ERDC research and development community. This special report describes the discussions and outcomes of the 2019 Nearshore Placement Workshop.

30 Apr 2020

PUBLICATION NOTICE: Seamless Integration of Lidar-Derived Volumes and Geomorphic Features into the Sediment Budget Analysis System

Abstract: This Regional Sediment Management Technical Note provides a workflow and case study documenting the process to integrate lidar-derived volume changes and changes quantified from geomorphic features into the Sediment Budget Analysis System. Sediment budgets provide an understanding of a region’s sediment sources, project needs, processes, data gaps, engineering actions, and ecological considerations. Elevation data from profiles or lidar, sediment characteristics, dredging and placement information, along with other coastal datasets, are used to understand sediment pathways and develop sediment budgets for a region. Workflows and tools have been updated or modified to integrate sediment budget tools, volume change tools, and remote sensing data for the creation of comprehensive regional sediment budgets. 

30 Apr 2020

PUBLICATION NOTICE: Geochemical Fingerprinting of Sediment Sources Associated with Deposition in the Calcasieu Ship Channel

Abstract: This Regional Sediment Management Technical Note (RSM-TN) demonstrates how geochemical fingerprinting techniques were used to distinguish probable sediment sources to the Calcasieu Ship Channel (CSC). These methods were applied to sediment samples collected from suspected source areas identified in past sediment budget studies. The techniques can be used by managers and stakeholders to make more informed decisions on best practices for managing sediment and mitigating sediment deposition within the channel.