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US Army Corps of Engineers Lock Performance Monitoring System

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Definition of Terms


Definition of Terms


Lockage Information

Barge: Generally, a boat without its own power used for transporting commodities. For reporting purposes the term barge also includes self-propelled vessels carrying commodities, e.g. a filled Dry Cargo Vessel would be counted as one vessel and one barge.

Barges Processed: The number of barges in a flotilla that have traversed the lock. For a cut-based report, this is the number of barges that have passed through the lock in one cut. For a flotilla-based report, this is the total number of barges in the flotilla that have passed through the lock so far.

Chamber: Each of the one or more structures at a lock providing the equipment necessary to move a vessel between differing water levels on a waterway. For more information on the characteristics of locks and chambers, please see http://www.navigationdatacenter.us/lpms/pdf/lkgenrl.pdf

Cut: Generally, a traversal of a lock in a single direction. For flotillas entering a smaller lock, where a chamber is too narrow to fit the vessel and its barges through, the flotilla is separated in to several trips through the lock, with each carrying a portion of the total barges; each of these trips is called a cut.

Direction: An indication of whether the traffic is traveling upstream (towards the maximum mile marker), or downstream (towards mile marker zero) on the waterway.

Flotilla: A tow with barges or a self-propelled vessel that is carrying a commodity.

Lock: The site, consisting of one or more chambers, that is used for raising and lowering watercraft between differing water levels on a waterway. For more information on the characteristics of locks and chambers, please see http://www.navigationdatacenter.us/lpms/pdf/lkgenrl.pdf

Vessel Name: The official name of a vessel as entered in the Coast Guard vessel database. The names from this database are periodically synchronized to ensure updates to names are captured. The USCG database can be found here: http://cgmix.uscg.mil/PSIX/PSIXSearch.aspx

Vessel Number: The identification number from the Coast Guard vessel database, which can be searched here: http://cgmix.uscg.mil/PSIX/PSIXSearch.aspx

Timining Events

Each discrete timing event as captured when a vessel or flotilla traverses a lock. A delay is the time between the first Start of Lockage and the Arrival Time. Processing Time is difference between the last End of Lockage and the first Start of Lockage.

Arrival Time: The date and time when a vessel nears the lock and signals that it is ready to use the lock. At this time, lock personnel designate a vessel as having joined the queue. For a lock with a long queue, the call to the lock may still place the vessel several miles away.

Start of Lockage Time (SOL): The date and time when the lock is ready to chamber a vessel; signal to enter is given by the lock operator.

End of Lockage Time (EOL): The date and time when a vessel has completed traversing a lock, and the lock can be dedicated to serving another purpose.

Delay: The time in minutes spent in queue awaiting lockage, i.e. the difference between the first SOL and Arrival Times.

Processing Time: The time in minutes taken for a vessel to completely traverse the lock with all of its barges, i.e. the difference between the final EOL Time and the first SOL Time.