Limnological Monitoring on the Upper Mississippi River System, 1993-1996: Long Term Resource Monitoring Program. Havana Field Station

摘要

Since 1988, the Long Term Resource Monitoring Program (LTRMP) staff have performed basic limnological field measurements in the Upper Mississippi River System. The period of this report (1993-96) includes a major revision of the LTRMP sampling design in 1993 that added randomization, broader spatial coverage, and increased monitoring of tributaries and locations that allow monitoring of material transport. Two significant floods (1993 and 1995) occurred in the reporting period. In 1993, the La Grange reach of the Illinois River was above the 1940-96 mean river stage for most of the year and was below flood stage for only three brief periods. The flood in spring 1995 receded sooner than in 1993; however, the 137 m (450.66 feet) peak on May 31, 1995, was the third highest river elevation recorded at Havana, Illinois. Low dissolved oxygen levels in the main channel were also notable in 1993-96, with concentrations at or below 5 mg/L observed each year.