Hydrologic modification for habitat improvement in the Finger Lakes Barko, J. W., R. F. Gaugush, W. F. James, B. L. Johnson, B. C. Knights, T. J. Naimo, S. J. Rogers, J. S. Sauer, and D. M. Soballe. 1994. Hydrologic modification for habitat improvement in the Finger Lakes: Pre-Project Report Number 3, 1994. Report by the National Biological Survey, Environmental Management Technical Center, Onalaska, Wisconsin; the U.S. Army Corps of Engineers, Waterways Experiment Station, Vicksburg, Mississippi; and the National Biological Survey, National Fisheries Research Center, La Crosse, Wisconsin, for the National Biological Survey, Environmental Management Technical Center, Onalaska, Wisconsin, September 1994. LTRMP 94-T002. 56 pp. (NTIS #PB95-166823) ABSTRACT The Finger Lakes Habitat Rehabilitation and Enhancement Project (HREP) is intended to improve winter habitat conditions for fish in a series of interconnected backwater lakes of the Mississippi River near Alma, Wisconsin. Winter habitat requirements (temperature, flow velocity, and dissolved oxygen) for the target fish population in the Finger Lakes have been defined and limnological efforts have been aimed at quantifying the spatial-temporal patterns and interrelationships among water movement, oxygen, and temperature. The progress to date (preconstruction) has included detailed investigations into (1) system hydrology (including dye-tracer studies), (2) oxygen supply and depletion, (3) temperature regime, (4) aquatic vegetation distribution, composition, and abundance, (5) macroinvertebrates, and (6) target fish species movements and food base. This report is the third in a series addressing preconstruction conditions. The report summarizes results of studies conducted during 1993. KEYWORDS aquatic habitat, rehabilitation, Upper Mississippi River, fish, backwater lakes, limnology, hydrology, sedimnetation, macroinvertebrates, aquatic vegetation