Continuous Hydrological Modeling using Soil Moisture Accounting Algorithm in Vamsadhara River Basin, India

Abstract

In this study, a continuous soil moisture accounting (SMA) algorithm was used in a Hydrologic Engineering Center- Hydrologic Modeling System (HEC-HMS) to model stream flow in the Vamsadhara River Basin in India. The spatial domain of the catchment was discretised into smaller sub-basins to account for catchment heterogeneity in terms of topography, land use and soil. The SMA algorithm in HEC-HMS was calibrated using data from 1984 to 1989, and has been validated for the period from 1990 to 1993 on a continuous time scale. Statistical and visual evaluation was conducted to determine the performance of the HEC-HMS model in the Vamsadhara River Basin. For the calibration period, the performance of the model ranges from good to very good with a coefficient of determination R 2 =0.71, Nash-Sutcliffe Efficiency EFF=0.701, percentage error in volume PEV=2.64%, percentage error in peak PEP=0.21%, and index of agreement d=0.94. Similarly, the model performance for the validation period ranges from good to very good with R 2 =0.78, EFF=0.762, PEV=12.33%, PEP = -15.2%, and d= 0.93. Sensitivity analysis of model parameters has also been conducted and the ranking of different parameters have been assigned based on their sensitivity in terms of percent change in simulated runoff volume. Sensitivity analysis helps to understand the behaviour of the model. Overall, the SMA procedure in the HEC-HMS conceptual model performed satisfactorily and can be used for long-term runoff modeling in the Vamsadhara River Basin.