Monthly data, not seasonally adjusted
For reporting rivers, inland commercial traffic in 2008 spent 238,997 hours in lockage and 193,964 hours waiting for lockage. The greatest total delay in 2008 was at Lock 52 on the Ohio River, with 32,137 hours; this lock will be replaced by the currently under-construction Olmsted Lock. Tonnage at Mississippi River locks has decreased from 708 megatons in 1998 to 442 megatons in 2008, while locked tonnage at the Ohio River locks has remained relatively steady, with 1,025 megatons in 1998 and 1,033 megatons in 2008.
Monthly data, 12-month centered moving average
A moving average facilitates analysis of trends in highly variable data series.
|Commercial Vessel and Tow Delay||Jul-08||Jul-09|
|Total Ohio River System Hours of Delay||9,265||8,446|
|Percent change from same month previous year||-45.04||-8.83|
|Total Upper Mississippi River System Hours of Delay||9,775||9,055|
|Percent change from same month previous year||-25.88||-7.36|
|Total Other Waterway System Hours of Delay||2,254||2,270|
|Percent change from same month previous year||-1.44||0.71|
NOTES: Data for the Upper Mississippi River System includes the Mississippi (north of the Ohio confluence), Illinois, Chicago, and Kaskaskia Rivers. Data for the Ohio River System includes the Ohio, Cumberland, Green, Barren, Kanawha, Allegheny, and Monongahela Rivers. Other rivers for which data are available are the Arkansas River, which has a confluence with the Mississippi below the Ohio, and the Tennessee and Clinch Rivers, which ultimately flow into the Ohio, but also feed traffic to the Tennessee-Tombigbee Waterway.
SOURCE: U.S. Army Corps of Engineers, Navigation Information Connection, Operations and Maintenance of Navigation Installations Report 10W, available at http://www2.mvr.usace.army.mil/nic2/default.cfm as of August 2009.