1400 (2) - Laserfiche WebLink

Home Browse Search

It is obvious from the geology of the area that these meanders are en~renched meanders different from the conventional meanders in alluvial plains. This contention was also supported by the finding that the observed meander characteristics did not show any correlation with the dominant discharge at Deer10dge Park. The hydrograph at Deerlodge Park was prepared by adding the mean monthly discharges of the corresponding months from the Little Snake River and the Yampa River, and the dominant discharge was taken as 8900 cfs. The meander data were then compared with some of the available relationships for entrenched meanders. According to Bates, MB is given by Equation 1 while Inglis suggested the use of Equation 2 for MB. Me = 30.8 Ws Me = 27.30 Ws (1) (2) The relationships for ML given by Inglis and Dury are given by Equations 3 and 4 respectively. ML = 11.45 Ws ML = 7 to 10 Ws (3) (4) In the above equations Ws is the bankful width of the river. In estimating the values of Me and ML from the above relationships, the value of Ws was taken as the width of the river. The values of MB obtained from Equations 1 and 2 were in general 3 to 4 times larger than the actual values; on the other hand, the values of ML obtained from Equations 3 and 4 were. comparable with the actual values only for a few meander loops. Figure 2 shows the variation of ML with R for the obser~ed values. On this figure, the relationship between ML and R for entrenched meanders proposed by Young (1974) has also been plotted for comparison. It can be seen that, on the average the Yampa River data follow Young's relationship. The study of the topographic features of the Yampa River a 150 indicates the presence of cliffs more than a thousand feet high espe- cially on the inside bends of the entrenched meanders. Thus, the meanders are more or less confined within the high vertical walls of the river with little possibility of their lateral migration. The general meander pattern is, therefore, unlikely to be affected by any variations in discharge. 31 . 14 "'-lfl "~-,,,- ~~ (;, ,---" ~..,~~~<:. Y-;/to,..-; :" ., I!'> L;~ ~..: "~",- ",~:, "'"" L,I,H,;~ ~~~ ""~"" t" 'f 'I} " , ~,." " r _