Abstract:
Experience and observations of flood flows in river show that the flood peak attenuates as it travels downstream. Although lateral flow and flow from tributaries may add up to the flow and lead to some increase in the peak. The reduction in peak is caused by irregularities in the width of the cross section of the flow and storage effect of the reach. Methods quantifying this attenuation have been tried in the past. Cunge evolved a method for estimation of these. He started with the well known Muskingum method which works on wedge and prism storage concept. The Muskingum method uses linear storage equation which is another form of stage discharge relationship. Cunge observed that the above equation will not allow the attenuation, ( reduction in peak), but Muskingum method produces attenuation. Cunge explained that finite difference formulation of continuity equation, in the case of Muskingum method, produces truncation errors when compared with Taylor series expansion.
Cunge derived equations to find the routing parameter 'x' of Muskingum method in terms of average slope, and width. R.K.Price, improved upon this work. He incorporated variations in the width and slope instead of using average, since
these are the features that produce attenuation.
The user manual describes the stepwise computations involved and the computer programme The input specifications. and output descriptions are explained with example. An example application to a flood observed in 1978, at Mortakka on river Narmada, is also included.
