Comparison of the Statistical Regression and Fuzzy Methods for Estimating Sediment Load for Telvar River

Subject Areas : Geopolitic

Baharak Motamedvaziri ¹ , Hasan Ahmadi ² , Mohammad Mahdavi ³ , Forood Sharifi ⁴

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Received: 2014-11-29 Accepted : 2014-11-29 Published : 2009-03-21

Keywords: suspended sediment load, USBR, FAO, Fuzzy Logic, Telvar river,

Abstract :

Estimation of rivers sediment load is one of the most important problems for designof hydraulic structures, investigating water quality, conserving fish habitate, estimatingerosion and determining watershed management effects.There is two metheod for estimating sediment load: empirical and regressionmethods. Existence of numerous empirical methods for estimation of river sedimentload, a wide range of calibration coefficients shows that a suitable analytical orempirical method does not yet exist to accurately estimate the sediment load.Therefore, the measured discharges and sediment concentrations in hydrometrystations are statistically analyses for an accurate estimation of sediment loads in rivers.In usual statistical methods a power function is generally fitted on the data sets of flowand sediment discharge and thus the total sediment load could be calculated using thisfunction. These methods are not able to recognize and separate the specific datameasuring conditions. Therefore, they are not only able to accurately estimate thesediment load, but also can not show the temporal variation of sediment loads. In spiteof this problems, researcher are using Artificial Intelligence methods such as FuzzyLogic, nowadays.In this study, the measured suspended sediment load at hydrometry stations ofTelvar River is analyzed using USBR and FAO methods (usual statistical methods).Furthermore, Sediment suspended load are estimated with a model developed based onFuzzy Logic rules. Then the results of these mothods are compared. This researchstudy has shown that the temporal variation of sediment loads can be analyzed using afuzzy method. Also the, results obtained using the fuzzy method in comparison withthe corresponding values obtained using the usual statistical methods shows a bettercorrelation with the observed values. In all stations the fuzzy method estimated thesediment loads between ones obtained using statistical methods.