International journal of agricultural invention, Jun 30, 2017
A geomorphological instantaneous unit hydrograph (GIUH) model was developed for a watershed of Da... more A geomorphological instantaneous unit hydrograph (GIUH) model was developed for a watershed of Damodar valley corporation, Hazaribagh, using Nash (1959) and Itrube (1982) methods to compute peak discharge (qpeak) and time to peak (tpeak). The model was calibrated and validated for five storm events, i.e. June 24-25 (1992), October 12-13 (1993), November 2-3 (1993), June 28 (1994) and August 6 (1996) by comparing their ordinates with the ordinates of instantaneous unit hydrograph (IUH). The GIUH was tested with absolute prediction errors (APE) of the ordinate of peak discharge. On comparison, it was found that, most of the GIUH models overestimated the runoff at initial stage, while underestimated at the latter stage in comparison to the IUHs, which was mainly due to consideration of const ant value of ะค-index, for computation of effective rainfall. The absolute prediction errors (APE) were computed to be 5.97, 18.09, 23.32, 9.64 and 7.52% of the ordinates of peak discharge for the storm events
In recent years, geomorphological instantaneous unit hydrograph (GIUH) approach to estimate the r... more In recent years, geomorphological instantaneous unit hydrograph (GIUH) approach to estimate the runoff from a watershed due to different storm patterns has gained wide acceptability for watersheds with scanty data. In this study, a user-friendly event based computerized GIUH model, GIUH_CAL, was developed. GIUH_CAL model incorporates an infiltration component. Depending on the availability of soil and infiltration data, the model offers a choice among three methods of infiltration calculation, viz., Richards' equation, phi-index method and Philip two term model. The graphical user interface (GUI) of the model is based on mouse-driven approach with pop-up windows, pull-down menus, sub-menus, toolbar, statusbar and button controls including comprehensive context-sensitive help file. GIUH_CAL model displays generated instantaneous unit hydrograph (IUH), unit hydrograph (UH) and direct runoff hydrograph (DRH) of the watershed graphically and processes statistically. Modelling efficiency (ME), coefficient of residual mass (CRM), root mean square error (RMSE) and coefficient of determination (r 2) are used as the performance criteria. The model was tested for two distinctly different watersheds, i.e., a 4th order Guptamani watershed in tropical sub-humid region and a 3rd order Upper Chhokeranala watershed in semi-arid region of India. The results show that model performs satisfactorily for both test watersheds and performance is much better with Richards' equation option of infiltration calculation as compared to phi-index method and Philip two term model.Thus, GIUH_CAL model can be adopted as a standard tool for modelling rainfallerunoff transformation process in scantily gauged watersheds.
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