Challenges with Sedimentation
Sustaining the viability of a maritime recreational and industrial activity depends upon maintaining navigation channels, including depths of approach channels, and berths at marine terminals and marinas. Natural movement of sediment, as well as human activities such as dredging, are an ongoing engineering concern.
Solutions Provided by EEMS
EEMS is frequently used to simulate sediment resuspension and transport. Two sediment models are available in the EFDC+ model. The first is the conventional EFDC sub-model developed at Virginia Institute of Marine Science which accurately simulates cohesive and non-cohesive transport. Alternatively, the user may select to use the state-of-the-art SEDZLJ sub-model developed by Sandia National Labs. This is an increasingly favored approach and an improvement on previous models because it may directly incorporate site-specific data (flume studies), while maintaining a physically consistent, unified treatment of bedload and suspended load.
Examples of Studies Done with EEMS
The US Army Engineer Alaska District has been assessing hydrodynamic and port sedimentation issues associated with proposed phased expansion and deepening of the Port of Anchorage. A series of numerical model simulations were performed to assess the impact of the proposed expansion configurations on sedimentation rates within the port. The EFDC surface water modeling system was used to perform these simulations.
A multidimensional hydrodynamic model of the Little Lake Butte des Morts (LLBdM) was developed in order to support studies of sediment transport dynamics. The insights gained in the modeling provided an enhanced conceptual understanding of sediment and PCB dynamics in LLBdM. This in turn impacted the interpretation of historical and ongoing studies.
A high resolution curvilinear model of the Novato Creek, including basins/floodplain was developed, with masks to represent the levee system, and multiple weir/overflow sections to simulate levee overtopping. This grid was combined with this a coarser domain wide model of the Novato Creek below Hwy 37 and above the tidal mud flats on San Pablo Bay. A suite of practical and self-mitigating alternatives to the flood management system within Novato Creek and its tributaries were modeled. Goals included maintaining and improving the existing level of flood protection, reducing dredging costs and associated impacts, improving the efficiency of flood control operations and maintenance, utilizing and supporting natural processes, and adapting to climate change.
Newtown Creek Hydrodynamic and Sediment Transport Studies
“Newtown Creek was designated a Superfund National Priority Site in 2010/2011 under the guidance of the USEPA. A complete condition survey, last performed in 1991, was performed in April 2009 by the USACE New York District. Sampling and testing for possible future upland placement will be coordinated with the NYSDEC, NYCDEP and other stakeholders. The entire channel was last dredged in 1951 with the removal of 80,000 cys of material. In the 1950s and 1960s, portions of Dutch Kills and English Kills were dredged. The channel has been subject to various industrial contaminant inputs along the river over the past several decades. As a result, the material to be removed may be too contaminated to dredge and place in approved upland sites. New York City Department of Environmental Protection is the local sponsor. Economic re-development of the area is planned. Coordination with the NYCDEP is maintained.” Source
EFDC is being used extensively in hydrodynamic and sediment transport models that will be applied to Newtown Creek, New York. It is selected due to being open source and being linked to a sediment transport model that has the capability to utilize erosion rate data obtained from Sedflume testing (i.e., SEDZLJ capabilities). Section 4, Modeling Memo 1
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