Currently, there are 2 reporting methods being used. The LPMS (Lock Performance Monitoring System) and Vessel Operating Reports (VORs), which are required by law to be submitted to the Institute of Water Resources (IWR), a division of the US Army Corps of Engineers.
The lock performance measurement system (LPMS) is collected at the Corps lock by the Lock Operator. The main purpose of this data is to track number of lockages by types of vessels. It is reportedly not accurate for determining commodity flow to include product type and volumes. For accuracy we reportedly should look to the IWR which, by law is reported by the owner or operator of the vessels (barges). Because this is the reporting system used to determine the metric used, it is important all users are reporting.
Using the lock performance measurement system (LPMS) is not an accurate metric system to determine the amount of cargo shipped on the waterways. The LPMS is an attractive tool because it is the most up-to-date information available, but it is the data from the IWR Statistics Center that is used in the annual U.S. Waterborne Freight reports. Cargo shipped in between the locks where measurements are being taken are not being captured.