Modelling of spring discharge in mid hills of north-west Himalayas

The discharge data of a perennial spring (Fakua) located in mid hills of North-West Himalayas was recorded for the period of 6 years (1999–2004). The maximum and minimum daily observed discharges were found to be 115.20 x 10³ litres in September (2000) and 1.24 x 10³ litres in July, respectively. Under high variability of daily discharge, two models (namely, model-1 and model-2) have been developed using Sigma-Plot and Curve Fitting softwares to simulate the daily spring discharge. The models were calibrated with daily discharge data collected during 2001 -2002 and validated with daily discharge data collected during 2003 -2004. The hypothesis for goodness of fit, tested by Kolmogorov-smirnov, was found significant for both the models. Coefficient of determination of Model-1 was 97.73 per cent having higher agreement with discharge dataset of validation period (2003), while coefficient of determination of Model-2 was 96.02 per cent having good agreement with datasets of both the validation periods (2003 & 2004). The coefficient of efficiency, RMSE & PI for the model-2 have been found in satisfactory range. For predicting/generating missing data of daily discharge of perennial springs, these models could be a powerful tools.