Investigation of the Efficiency of the Fuzzy Regression Method in Reconstructing Monthly Discharge Data of Hydrometric Stations in Great Karoon River Basin.

There are different methods of reconstructing hydrologic data. depending on theconditions of the station a particular method can produce the best results. generally, inorder to estimate the lost data in a station and its surrounding stations, hydrologic,climatologic and/or physiolographic similarities are used. recently, the fuzzy regressionmethod has been used to reconstract the hydrologic data. in this research, the efficiencyof this method in reconstructing the montly discharge data of hydrometric stations incomparison to other methods was investigated. the credited omission method was used inthis investigation, then by omitting the observed data deliberately, their values wereestimated using the different methods. afterwards, by the use of the statistical index ofroot mean squared error (rmse) the best method of reconstruction was determined. theresults showed that the best methods of reconstructing monthly discharge data for thehydrometric stations in the great karoon river basin in order of accuracy are artificialneural network, simple linear regression, multiple linear regression, normal ratio, fuzzyregression, autoregresive and graphical methods.