Evaluation of modified CN methods for watershed runoff estimation using a GIS-based interface

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• 作者：J.P. Patil ; A. Sarangi ; A.K. Singh ; T. Ahmad
• 关键词：Prey– ; predator model ; Positive solutions ; Existence ; Multiplicity ; Bifurcation ; Stability
• 刊名：Biosystems Engineering
• 出版年：2008
• 出版时间：May 2008
• 年：2008
• 卷：100
• 期：1
• 页码：137-146
• 全文大小：490 K

文摘

The procedure is based on three modules: a stochastic rainfall generator module, a hydrologic loss module and a flood routing module. In the rainfall generator module the rainfall storm, i.e. the maximum rainfall depth for a fixed duration, is assumed to follow the two components extreme value (TCEV) distribution whose parameters have been estimated at regional scale for Sicily. The catchment response has been modelled by using the Soil Conservation Service-Curve Number (SCS-CN) method, in a semi-distributed form, for the transformation of total rainfall to effective rainfall and simple form of IUH for the flood routing. Here, SCS-CN method is implemented in probabilistic form with respect to prior-to-storm conditions, allowing to relax the classical iso-frequency assumption between rainfall and peak flow.

The procedure is tested on six practical case studies where synthetic FFC (flood frequency curve) were obtained starting from model variables distributions by simulating 5000 flood events combining 5000 values of total rainfall depth for the storm duration and AMC (antecedent moisture conditions) conditions. The application of this procedure showed how Monte Carlo simulation technique can reproduce the observed flood frequency curves with reasonable accuracy over a wide range of return periods using a simple and parsimonious approach, limited data input and without any calibration of the rainfall-runoff model.