CS(AR)-25/96-97 : Analysis of surface and ground water flow process in Western. Ghat of Dakshina Kannada district, Karnataka state

Abstract

Through the study area receives more than 4000 mm rainfall annually, the area faces acute shortage of fresh water during summer months. Besides, the river and the adjoining wells turns saline during summer months. These problems have a great impact on human settlement and their socio-economic conditions. In order to identify the cause for scarcity of water during dry months inspite of high rainfall in the area, geohydrological and geomorphological studies are the need of the hour. With this in view, a detailed study has been taken up for Sithanadhi and Nethravathi basins by the following analyses to identify the surface and sub-surface flow process of the study area.

The distribution of rainfall has been analysed and the importance in peak discharge and quantum of yield from the basin and also in recharging the groundwater aquifer is studied. The annual rainfall departure analysis has shown the deviation of the rainfall from the normal rainfall over a period of time. The probability analysis of annual rainfall is used to predict the relative frequency of occurrence in different group of intervals of annual rainfall.

The rainfall recharge and discharge condition of the study area is reflected by the relationships between the water level fluctuation and monthly rainfall.

Water balance components such as precipitation, surface runoff, baseflow. wetting. and vaporisation are estimated to analyse each components with respect to the annual precipitation using conceptual catchment water balance model and relationship between the components have been analysed.

Geomhorpological parameters which are influencing on movement of water and thereby the effect on volume of runoff is studied.

Land use and geology considered for the effect on runoff process of the basin as the variation of abstraction factors depend on the land use and its cover. The range of infiltration rate is correlated with surface runoff, recharge and drainage condition.