TR(BR)-148 : Regional low flow analysis using morphological factors for upper Narmada

Abstract

The term low flow is broadly used to describe stream flows that are significantly below average or normal flow levels. Reliable estimation of low stream flows is necessary to investigate drought characteristics of the basin. The important variables in the study of low stream flows are the magnitude, frequency and duration. Regional models are developed relating the flow characteristics with climatic, hydrogeological and morphological factor for estimation of low flow variables.

In the report a regional hydrological model is developed for estimating flow duration curve at ungauged sites of upper Narmada basin using only morphological variables. The model is developed by relating the low flow characteristics with basin characteristics of six sub-basins of upper Narmada. The analysis of variance and correlation analysis suggested that the characteristics related to total length of channel, drainage area and slope of the catchment could be the main morphological variables in the model. Based on the correlation analysis, the variable as total length of channels, drainage density and slope of the main channel length are used in the development of hydrological model. It is also observed that the variable, the total length of the channel explains the maximum variance in the model followed by drainage density and slope of main channel length. The models developed explains the adjusted coefficient of determination greater than 0. 90.