RN-35 : Flood foresting models

Abstract

A hydrological forecast is the prior estimate of the future state of hydrological phenomena based on the knowledge of underlying physical laws and the modifying effects of specific geographic conditions. The report gives various elements of flood forecasting i.e. necessity of flood forecasting and flood warning, types of river forecasts, development of hydrological forecasting, data requirements for forecasting etc.

The report briefly describes and reviews various flood forecasting models. The available models for flood forecasting can be broadly classified in three categories i.e.(i) The models that make use of equations of continuity, energy and momentum to describe the movement of water in the hydrological cycle (ii) conceptual models or watershed models which represent component processes in the hydrological cycle and (iii) Input-output models or black box models which identify a relationship between the input and output without attempting to describe the transformation process.

The review of literature reveals that models based on unit hydrograph and ARMAX type models are very simple to use and have shown good potential for online flood forecasting. The suitability of these models should be tested on broader data base.