TR-89 : Hydrological studies of Parda spring in Nainital

Abstract

The spring flow models which are hitherto available are based on the assumption of lumped recharge in the recharge zone of a spring. But in reality recharge to a spring is variable with time. With the -help of the existing models of the spring flow, the prediction of volume of live reserve inside the spring is only possible for lumped recharge A mathematical model for analysing the unsteady flow from a spring has been developed accounting variable recharge. The spring flow domain has been hydrologically decomposed into two domains,-i)recharge zone, and ii)transition zone. The spring's threshold point lies at the end of the transition zone. In the recharge zone, the flow has been assumed to be only in the vertical direction and in the transition zone the flow has been assumed to follow Dupuit-Forchheimer assumptions and the flow is in the horizontal direction. For solving the problem, the unsteady state has been assumed to be succession of steady states.

With the help of the present model. recharge to the spring flow domain, and live storage in the spring and springflow can be predicted for time variant recharge.

The model developed is applied\to Parda spring, Nainital for which several years of springflow and rainfall data are available. These data have been used to calibrate and test the model.