The assessment of rill irrigation and perforated pipes for Lowland paddy rice under the system of rice intensification (SRI)

Paddy and Water Environment - Irrigated paddy rice needs new strategies and tools to improve water use efficiency and productivity by applying just enough to sustain production with huge savings on...     

Calculation of bed load based on the measured data of suspended load

This paper proposes a method for establishing both the velocity profile and concentration profile for suspended sediment based on measured data consisting of average velocity and average suspended sediment concentration in the river and the irrigation channel. In addition, a numerical model for computing suspended load and bed load was also developed for computing bed load transport rate when measurable load is available. In this study, bed loads for published laboratory and field sediment data were computed using the presently developed numerical model based on four different bed layer thicknesses. The computed bed loads were found to be in reasonable agreement with the values from Einstein’s bed load function when the thickness of the bed layer was taken at 10θd or 0.05D. The numerical model developed in this study may be used to evaluate the validities of other bed load formulas.