Touraj Sabzevari; Mehdi Karami Moghadam
Abstract
Time-area hydrograph and Clark’s methods are commonly used for prediction of runoff in catchments. In the both methods, the Time-Area Diagram (TAD) of the catchment is needed. In this study, two methods for estimation of Dimensionless Time-Area Diagram (DTAD) are introduced. In the first method, ...
Read More
Time-area hydrograph and Clark’s methods are commonly used for prediction of runoff in catchments. In the both methods, the Time-Area Diagram (TAD) of the catchment is needed. In this study, two methods for estimation of Dimensionless Time-Area Diagram (DTAD) are introduced. In the first method, called geometric method, a hyperbolic function for the geometry of the catchment is assumed. Furthermore, travel time is assumed to be proportional to an exponent ( ) of flow distance to outlet. It was shown that the resultant DTAD equation is equal to USACE (1990) equation when is one. In another method, called Nash-TA, DTAD equation was derived as a function of Nash model parameters. The two developed methods were applied to Ajay catchment, in India, and Kasilian, Jafarabad, Shourandika catchments, located in Iran, and the results were compared to those obtained from the kinematic wave method. The efficiency coefficients for geometric method with being 0.6 and for the Nash-TA method were 0.971 and 0.955, respectively. The efficiency coefficient for geometric method in cases of =1, 1.5, 1.67 were 0.824, 0.484 and 0.161, respectively. The efficiency of the geometric method ( =0.6) and the Nash-TA method was satisfactory.
Seyed Hamid Reza Sadeghi; Seyedeh Laleh Razavi; Mohammad Mahdavi
Volume 1, Issue 2 , July 2009, , Pages 78-86
Abstract
Many different runoff prediction methods are being used among which SCS model has been applied throughout the globe. It is therefore very important to evaluate the circumstances and input specifications under which such models could be applied. The present study was conducted to investigate the role ...
Read More
Many different runoff prediction methods are being used among which SCS model has been applied throughout the globe. It is therefore very important to evaluate the circumstances and input specifications under which such models could be applied. The present study was conducted to investigate the role of rainfall main characteristics on accuracy of SCS model in runoff prediction for Kasilian and Darjazin watersheds. For this purpose, the simultaneous rainfall-runoff data were selected and the storm runoff was estimated using determining rainfall characteristic, providing Curve Number map and calibrating the model. In order to determine the effects of rainfall characteristics on model output, the standardized values of regression coefficient (β) of the best fitted multiple regression, developed between rainfall circumstances and maximum storage index coefficient, were determined. The results of the study showed the depth, maximum rainfall in concentration time, maximum 30 minutes intensity, 2nd quartile and 1st quartile have the highest rate of effectiveness on model output respectively.
