Application of Yalin and da Silva’s Regime Channel Determination Method to The Middle Yangtze River.

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Zhifang Yan, Wenhong Dai

Tuesday 30 june 2015

12:42 - 12:45h at Oceania (level 0)

Themes: (T) Sediment management and morphodynamics, (ST) River morphodynamics, Poster pitches

Parallel session: Poster pitches: 5B. Sediment - River

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Assessment of river regime state is of great significance for river flood control, river regulation, wharf construction etc.. Sarah(2000) had pointed out that in contrast to rational regime channel determination methods of Yang(1976), Chang(1979), White et al.(1981), etc., Yalin and da Silva’s method is the only rational method which, for a given fluid and granular material, requires specification of only the flow rate, Q, for the determination of regime channel geometry (regime width BR, regime depth hR, regime river bed slope SR). In this paper, the effectiveness of Yalin and da Silva’s method was evaluated by using 323 sets of measured data of flumes and fields. The results show the rationality of the method. In order to assess the stability of the Middle Yangtze River, the calculated regime values by using Yalin and da Silva’s method versus the measured values of the key cross-sections were plotted in graphs with perfect agreement line. The results indicate that the measured channel widths are, in general, fairly close to the calculated regime ones, however, the calculated regime depth versus the measured depth points fall above the perfect agreement line while the calculated regime slope versus the measured slope points fall below the perfect agreement line. These mean that the river widths are nearly at their regime state, the river depths are smaller and the river bed slopes are much larger than the predicted regime ones, which also indicate that the invested river reach of the Middle Yangtze River has not reached its regime state yet.