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Mean monthly discharges for October, 1986 through March, 1987 were higher than historic means (1917-1988), while mean monthly discharges for October, 1987 through March, 1988 were lower than historic means (Figure 11). Wick and Hawkins (1989) used regression analysis to determine the relationship between river stage and discharge at RM 81.1 of the Yampa River. Two data sets were compared; one from the coldest portion of the winter--mid-December to mid-February--and the second from the warmer, high- discharge period of early March. Both data sets showed a stage change of about 0.2 feet (6 cm) for every 20 cfs (0.6 cros} reduction in discharge. This relationship predicted that discharge reduced from lowest measured flow of 142 cfs to 75 cfs (4.0 ems to 2.1 cros) would result in a stage reduction of about 0.7 feet (21.3 cm). During Winter 2, Wick and Hawkins (1989) further investigated the relationship between stage and discharge by comparing water surface elevation change to changes in discharge in the main channel and in an embayment, with and without ice cover. The lowest main channel discharge measured was 142 cfs (4.0 ems) on December 15, 1987, and the highest was 340 cfs (9.6 cros) on March 3, 1988. Similar comparisons were made for an embayment, where ice thickness increased from 0.85 feet (25.9 cm) on December 15 to 2.12 feet (64.6 cm) on March 15. Water surface elevations increased throughout winter, compensating for a corresponding increase in ice thickness, and resulting in relatively stable effective depth. Effective depth varied only 0.1 feet (3.0 cm) between December 15 and February 17. In early March, effective depth increased 0.3 feet (9.1 cm) in response to a discharge of 340 cfs, then decreased dramatically by March 15, just prior to ice-out. This decrease in effective depth was caused by a drop in stage and bed changes resulting from increased water velocities along shorelines. These stage-discharge relationships demonstrate effects of different ice conditions on flow and river stage.- As surface ice began to form, shoreline ice formed along the edge of the river, effectively reducing discharge while increasing water surface elevation (cross sectional area was reduced by ic;e mass controls). For example, relative stage height under ice-free conditions at a main channel cross section was 90.61 feet at a discharge of 236 cfs (6.7 cros). Relative stage height under ice on February 7, 1988 was 91.77 feet at 229 cis (6.5 cros)--a change oC 1.16 feet for only a 7 cfs change in discharge. Another set of measurements showing ice cCl'ect was a comparison o£ identical stage height at two drastically different discharges. Maximum relative stage height under ice was 92.14 feet 18