Theme 4-15-Hydrological characteristics of arid zone drainage basins in Western Rajasthan, India.

Abstract

Hydrological characteristics of Guhiya basin, a typical drainage basin of arid zone of Rajasthan (India) and consists of various type of landform and landuse was studied during 1988-94. Temporal and spatial rainfall variability of daily and annual rainfall were found to be very high. Data suggests that one wet spell once in five year has 98% probability, whereas, stormwise one wet spell of >200 mm annually has 50% probability. The probability of normal rainfall (75-125%) is nearly 34%. The typical depth-area curves for 1-day, 2-days and 3-days storms developed suggests that the maximum rainfall depth has decreasing trend with increase in basin area for each duration. Rainfall intensity-duration-frequency relationship developed predicts the rainfall intensity for different recurrence intervals and different duration storms with perfect accuracy. The correlation coefficient computed for the good fit between observed and computed values is 0.98.

Estimation of runoff and sediment yield is the prime need for planning, designing and management of any water resources project. Linear and multiple regression models have been developed for all the basins. The rational method has been used for computation of peak discharge and value of runoff coefficient (C) has been predicted. Synthetic hydrograph has been employed to estimate the runoff. The relationship between basin lag and physical parameters for mountainous, foothill and plain alluvial drainage areas has been established with considerable accuracy. Runoff, peak discharge and sediment yield have been modelled using linear and multiple regression models. Relationship between sediment concentration and antecedent dry period suggests that the first seasonal flow generates comparatively high sediment concentration than the subsequent flows.