Limnological monitoring on the UMRS, 1993 1996: Lake City Field Station Soballe, D. M., R. Burdis, and W. Popp. 1999. Limnological monitoring on the Upper Mississippi River System, 1993 1996: Lake City Field Station. U.S. Geological Survey, Upper Midwest Environmental Sciences Center, La Crosse, Wisconsin, October 1999. LTRMP 99-P003. 17 pp. + Appendixes A F (NTIS #PB2000-103228) ABSTRACT Since 1988, the Long Term Resource Monitoring Program (LTRMP) has 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. Monitoring by the Lake City Field Station reported here shows water quality differences among the tributaries to Pools 4 and 5, spatial and temporal patterns within these pools, and the sediment and nutrient trapping effects of Lake Pepin, a natural impoundment of the Mississippi River. KEYWORDS Annual report, limnology, LTRMP, Mississippi River, water quality