Shobhit Maheshwari

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The transport effectiveness of a stream flow event of a certain magnitude in carrying a sediment load is defined as the product of the effect of that event and the frequency with which it occurs. This approach is famously known as Magnitude-Frequency Analysis (MFA). MFA has been commonly used to calculate “effective discharge” which is considered as the stream flow that is responsible for transportation of the majority of the sediments from a river basin over a long period of time. In MFA, the stream flow at a location is assumed to follow a continuous probability distribution whereas the sediment transport is described by a rating curve between stream flow and sediment load. Despite the apparent good fit to the data, there are problems using a rating curve to predict sediment load. The sediment load carried through a stream network can be affected by the variability in stream flow occurring during different months or seasons (i.e. time scales) and consequent hysteresis phenomenon. Prediction of sediment load can be improved by constructing separate rating curves for various time scales. In this study, daily stream flow was assumed to follow the log normal distribution, and rating curves (between stream flow and sediment load) have been developed for total, monsoon, individual months data and considering hysteresis phenomenon for total and monsoon data in transport of sediments. Finally, MFA based effective discharges were calculated at 16 stream gauges in the Godavari River basin, India. The results of this study can find use in the effective planning and functioning of dams/reservoirs.