The potential effects of propeller-induced velocities (propeller wash or propwash) on the erosion, transport, and re-suspension of contaminated sediments can be significant. EEMS uses an integrated propeller wash sub-module that can utilize the automated information system (AIS) telemetry from vessels regarding their position and orientation every few minutes or any user-defined ship track information.

Propeller Wash Setting in EE Forms.

The Propeller Wash module has been developed to simulate the impact of ship propeller jet on bed erosion and suspended solids. It is an important element in the development of plans for improvement and optimum utilization of waterways. It should be noted that the propeller wash does not have an impact on the model hydrodynamics by default. When simulating sediment this module will affect the movement of sediment, but propeller momentum must be turned on by the user to impact the model hydrodynamics.

To activate this module, RMC on Modules from the Model Control form, then check on the box of Propeller Wash as shown in the Figure 1. RMC on the Propeller Wash module under the Modules option in the Model Control as shown in the Figure 2. The Propeller Wash form will be displayed as shown in the Figure 3. This shows the total number of ships, tracks, and ship track points. The Propeller Wash form has three tabs consisting of: General, Ships, and Tracks tabs.

Figure 1. Activate Propeller Wash Module.

Figure 2. Edit Propeller Wash Module.

Figure 3. Propeller Wash Form: General tab.

Import AIS Data

The high-resolution, real-time AIS (Automatic Identification System ) ship traffic data collected by the U.S. Coast Guard for large vessels in the U.S. and international waters and is provided free on websites such as MarineCadastre.gov; Shipfinder.com and Vesselfinder.com. The ship track data in a specific time and location can be downloaded from websites and prepared in advance. The file can be imported to Propeller Wash form by using the Import AIS Data button as shown in Figure 4. Once clicking the Import AIS Data button, the Import AIS Ship Tracking Data window will pop up, as shown in Figure 5. Click on the Browse button to browse the data file. The example AIS ship track data file in CSV format is shown Figure 6. EE can search keywords in the column name of the data file to match the prop wash parameters. Once the AIS data is loaded, the Import Ship Tracks interface will update the Track Field Settings fields and display all available data values as shown in Figure 7. The user should pay attention to the ship speed unit (i.e., column 4 in this case) in the data file because EFDC+ uses the meter per second unit for ship speeds for model simulations. Time Shift is used to convert the AIS data time from Universal Time Coordinated (UTC) to Pacific Daylight Time. Check on the box Clear Current Track Data Before Importing to erase all the existing ship tracks. Click OK button to start importing ship tracks, and when the process is complete the total ships and total tracks will be updated as shown in Figure 8.

Figure 4. Import AIS Data.

Figure 5. Import AIS Ship Tracking Data.

Figure 6. AIS Ship Track Data File (CSV Format).

Figure 7. Import Ship Tracks Interface After Loading AIS Data.

Figure 8. Ship Information After Importing AIS Data.

General tab

The General tab consists of four frames: Propeller Momentum Linkage to EFDC+ Hydrodynamics, "Mass" Erosion Options for Cohesive Sediments, Jet Velocity Regions (based on Propeller Diameter), and Sub-Grid Setting frames as shown in Figure 9. Each of these frames is described below:

1. Propeller Momentum Linkage to EFDC+ Hydrodynamics

If the Propeller Momentum Factor is set to 0 the model will neglect the momentum effect. If it is >0 the model will add propeller momentum to the EFDC+ flow field

2. "Mass Erosion Options for Cohesive Sediments

Fraction Eroded as Mass Erosion: will split the mass into the base and "mass" eroded material of the total mass of the cohesive class eroded
Multiplier for "Fast" Settling of Eroded Mass: is a multiplier to increase the source cohesive settling velocity

3. Jet Velocity Regions (based on Propeller Diameter)

Efflux Zone: the efflux zone multiplier
Zone of Flow Establishment: the flow establishment zone

4. Sub-Grid Setting

Number of Axial Elements
Number of Radial Elements
Sub-Grid Length Multiplier
Sub-Grid Width Multiplier

Figure 9. Propeller Wash Form: General Tab.

Ship tab

The ship tab is shown in Figure 10. The list of ships is displayed on the left of the tab. The Add button below the list of ships is used to create a new ship and and Delete button will remove a ship from the list. Search for a ship by entering the ship name in the search box, then the ship will be highlighted in the list.

Figure 10. Propeller Wash Form: Ships Tab.

When you right-mouse click (RMC) on a ship, there are a number of options provided, including:

Remove Selected Ship(s): LMC on a ship (or press the Ctrl + LMC to select multiple ships) then RMC to select Remove Selected Ship(s) to delete the selected ships from the ship list
Remove All Ships: will delete all ships in the list
Move Up: LMC on a ship to select then use this option to move up the selected ship up in the list
Move Down: is the opposite to the Move Up option
Sort Ship Names in Ascending Order: will sort ship names from the smallest to largest, 0 to 9, and/or A to Z
Sort Ship Names in Descending Order: will sort ship names from the largest to smallest, 9 to 0, and/or Z to A
Add New Ship: adds a new ship to the list

Figure 12. RMC's Ship Options.

The missing ship information can be filled in based on the MMSI code by using open-source online data or the EEMS Ship Database. Clicking Update button as shown in Figure 13 .The online downloading process will apply to each ship in a step-wise manner. After updating a pop-up message will appear to inform the download process is completed as shown in Figure 14.

Figure 13. Update Ship Info.

Figure 14. Complete Update Ship Info.

EEMS also supports importing of ships from EEMS ship information database by clicking the Import Ships button. The EEMS ship information database will pop up as shown in Figure 15. Search either by name or ship information such as length, gross tonnage, deadweight tonnage, or year built. After checking the number of ships that meet the requirement will be listed as shown in Figure 16. Select the checkbox and then import to the ship list or close to exit the form. When the result of searching returns, if we check on the checkbox Clear Existing Ship Data Before Importing then, click the Import button, the old ship data will be deleted. If the checkbox Clear Existing Ship Data Before Importing is not checked. The new ship will be added, even though the new ship has the same name as the existing one. It means that overwrite is not happened.

When there are two ships with the same name, we can check their information and extract information from them to update to only one ship and remain it, and we should remove the other one.

Figure 15. Import Ships from EEMS Ship Information Database Form (1).