TN-33 : Hydrologic models for mountainous areas

Abstract

Estimation of runoff in Mountainous areas is required for the design, development and management of Water Resources Projects. Since the mountainous catchments have a complicated hydrological behaviour, the hydrological response would be controlled by a large number of climatic and physiographic factors which vary both in space and time. The complexity of the flood producing process in Mountainous regions makes the modelling difficult even by the most rigorous model. The limited availability of data makes it necessary to make adequate approximation and simplification to use them for mountainous catchments.

Several Watershed models are available and most of them were developed taking into account the component processes of the runoff formation as the basis of their development. These include the models for snow covered areas, non snow covered areas and catchments with both types of areas. Some models have capabilities to make use of the remotely sensed data as well.

A general review of hydrologic models was carried out with emphasis on studying the capabilities of models, the data requirement for them, techniques of evaluating model parameters their application to mountainous areas and associated difficulties and limitations are discussed. Tabulated information of some of the above models are appended.

Most of the models have been developed and applied abroad under prevailing conditions and assumptions. It is essential to test these models for Indian Mountainous catchments and modify where necessary to suit the hydrometeorologi- cal and physiographical conditions of Indian mountainous area.

Based on the review it is concluded that such of the models which are distributed in their approach and physically based are most suited for application to Indian mountainous catchments. SHE, UBC and Leavsley are some such models. Besides SRM and Sacramento could also be applied.