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18 1982 to present. The Yampa River record at Deer Lodge Park was extended by summing daily flows from the Yampa River at Maybell and Little Snake at Lily. The mean error between calculated and measured daily discharges at Deer Lodge Park was -1.5%. Errors were normally distributed, with over 70% of the calculated daily discharges within ± 15% of the measured value for each day. For comparisons of long-term changes in flow regime we partitioned the periods of record for both streams into pre-Flaming Gorge and post-Flaming Gorge segments. The pre-Flaming Gorge period was defined from water years 1947 to 1962, and post- Flaming Gorge from water years 1964 to 2000. The years 1962 and 1963 were omitted from the series because the reservoir was being filled, resulting in atypical hydrographs during that period. Our goal was to select from each of the pre- and post-Flaming Gorge series, annual daily flow hydrographs that represented wet, normal, and dry water years, respectively. This partitioning made it possible to examine differences in daily flow patterns, pre- and post-Flaming Gorge, during years having comparable water supplies. The partitioning process was conducted in the following manner. Recurrence intervals (Dunne and Leopold 1978) of mean annual flows from 1947 to 2000 for both gages were determined. Normal water years were defined by the median of the ranked data (having a 2-year recurrence interval). Water years having mean annual discharges closest to the long-term median were then selected from the pre-1962 and post-1964 subsets to represent normal or near-normal years. Above-normal water years were determined by ranking the mean annual discharges from highest to lowest and calculating the recurrence intervals for each year. Years having a 6-year recurrence interval were selected to represent above-normal water supplies. A similar process was used to select