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19 above the mouth of the Yampa River. Vanicek (1967) concluded that the Yampa River sufficiently ameliorated the cold temperatures of the Green such that fish populations below that point were little affected by the dam in 1963-1966. Figures 9-13 show the hydrographs for the 6reen River during 1962- 1966 at Jensen and Greendale. All years show a fairly normal seasonal flow pattern at Jensen, high in Mayor June, receding flow levels in July to lows in late summer. Flows from the Green River (6reendale) were fairly erratic and did not generally affect the seasonal pattern. The 1965 data does not show abnormal flows but rather appears to be a fairly normal flow year for the Yampa River, except that the highest peak oc- curred late in June, rather than during the more typical mid-late May period. This suggests that 1965 was a colder year than normal. Very high flows from Flaming Gorge Dam in March and April of 1965 produced an abnormal pattern for the Green River at Greendale, which also could have affected temperatures. Table 3 shows the mean monthly temperatures of the Green River at Jensen for 1962-1966. These data indicate that (Robert Kramer, unpublished field notes, Utah Coop. Fish. Res. Unit, it I il ~i il I. !,I q r! i'l .i ~! i ~.I ! ~ ' ~ !L I': II :11 ~I il ~l ~ h: ;1 j' April, May, and June temperatures in 1965 were colder than 1963,1964, or 1966, other post-impoundment years. The 1965 temperature pattern was probably created by the cold, ambient conditions causing the late runoff, as well as the large releases from Flaming Gorge Dam in April. Several researchers have studied the Green and Yampa rivers from 1967 almost continuously to the present. Young-of-the-year squawfish have not been found commonly in Dinosaur National Monument since 1966. Kramer ~ " ~