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Fuzzy unit hydrograph
Author(s) -
Bárdossy András,
Mascellani Gianluca,
Franchini Marco
Publication year - 2006
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2004wr003751
Subject(s) - hydrograph , fuzzy logic , runoff model , mathematics , vagueness , surface runoff , fuzzy number , transformation (genetics) , hydrology (agriculture) , fuzzy set , computer science , flood myth , geology , geography , geotechnical engineering , artificial intelligence , archaeology , ecology , biochemistry , chemistry , gene , biology
The unit hydrograph method, frequently used for representing the rainfall‐runoff transformation, is subject to a number of uncertainties related both to the model assumption and data acquisition, despite them usually being disregarded. A methodology to account for these uncertainties based on the fuzzy approach is proposed and illustrated. It is assumed that the unit hydrograph can be represented through a fuzzy schematization, and effective precipitation is also considered a fuzzy series; by applying the extension principle to the convolution integral a fuzzy runoff is obtained. In particular, the Nash cascade parametric form of the unit hydrograph is used, and its parameters are considered fuzzy numbers. The general methodology and the assessment of the parameters are explained using a case study relevant to the subcatchments of the Neckar catchment (southwest Germany). The proposed procedure enables bands to be calculated that describe the range of possible hydrographs for predefined h levels. The uncertainty in the runoff calculation is thus represented in terms of fuzzy vagueness by the width of these bands. The bands decrease with the increase of the h level. The calibrated parameters are then used with the extension principle for calculating the vagueness of different runoff characteristics, such as flood peak discharge and time to peak, as fuzzy numbers.