A flood frequency derivation technique based on kinematic wave approach
Date
1987
Authors
Cadavid, Luis Guillermo, author
Obeysekera, J. T. B., advisor
Salas, Jose D., committee member
Schumm, Stanley Alfred, 1927-, committee member
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Abstract
The present study deals with the derivation of a methodology to obtain a flood frequency distribution, for small ungaged watersheds, where the overland flow phase is considered to be an important timing component. In the hydrological literature, this technique comprises three components: a rainfall infiltration model, an effective rainfall-runoff model and the probabilistic component. The study begins with a review of the Geomorphological Instantaneous Unit Hydrograph (GIUH), in order to establish its applicability to the aforementioned type of watersheds. Some effective rainfall-runoff models currently used in the practice of hydrology, like the GIUH and models based on Kinematic Wave approach, lack the required features or do not consider all possible responses within the watershed. Therefore, a new model is developed and calibrated, based on Kinematic Wave approach, for a first order stream with two symmetrical lateral planes. The model is conformed by analytical and approximate solutions, the latter improved via regression analysis. The formulated model is used along with a statistical distribution for the effective rainfall intensity and effective duration, in order to derive the flood frequency distribution technique through the probabilistic component. The structure of the equations considered in the different components imposes a numerical algorithm to compute the flood frequency distribution curve for a given watershed. The derived technique is proved for hypothetical and real watershed configurations, showing its capability to forecast flood frequency curves for ungaged watersheds and to account for the influence of parameters on the physics of flood formation. Actual watersheds are conceived as first order streams with two symmetrical planes.
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Subject
Flood forecasting -- Mathematical models
Runoff -- Mathematical models