Propeller Wash
Propeller wash is the flow generated behind a rotating propeller. In areas with significant ship traffic, propeller wash impacts the sediment bed. It can cause resuspension and redistribution of contaminated sediments in urban waterfronts. EFDC+ contains a fully integrated propwash module that predicts bottom velocities, bed shear, and sediment resuspension using ship information, position, and speed that dynamically couples to the three-dimensional hydrodynamics of the waterbody (Craig, 2023). Furthermore, the propeller energy can be incorporated into the three-dimensional flow field behind the ships, as described in our EFDC+ Propeller Wash White Paper.
The EEMS propwash module has applications for contaminated sediment remediation sites where ship traffic and associated propwash impacts are observed. This feature allows more integrated propwash assessments for port and harbor engineers when performing stability analysis, engineering design, harbor management, and sediment management. It is essential when evaluating the impacts to a foundation or bulkhead due to propeller action, as well as harbor maintenance dredging. Propeller wash simulations are increasingly regarded as a critical component of Remedial Investigations/Feasibility Studies, as well as Remedial Design.
Import & Process AIS Data
Quickly load, process, and visualize the Automatic Identification System (AIS) data from U.S. government agencies such as MarineCadastre.gov or commercial operators. AIS data provides vessel time, position, course, heading, and speed, for the EFDC+ model. This can which can be efficiently imported into EEMS for editing and adjustment so that vessel tracks reflect the historical or theoretical movement of vessels in the waterbody. Such information is essential for litigation support and forensic studies.
Configure Vessel Properties
Load the physical characteristics of ships from many online databases to populate the EEMS ship database with information such as the dimensions and tonnage of each vessel. If data is unavailable, EEMS helps estimate these values so they can be entered into the system manually. This provides an accurate understanding of the active ships in the waterway and allows the impact of ships on sedimentation or erosion to be quantified.
Sediment & Toxics Fully-Coupled
The propwash module implemented in EFDC+ dynamically links the hydrodynamic grid representation of a water body of interest with ship paths, the hydrodynamic velocity field calculations, the propwash approach based on a combination of Maynord (1990, 2000) and Hamill (2016), the modules for bottom shear calculations, erosion flux, sediment transport, and sediment bound toxics transport. Contaminated sediment may be entrained and then further transported by currents induced by vessel traffic. This means propwash impacts the cleanup of contaminated sediment sites which may include a combination of dredging, capping, or in-situ treatment.
