عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Due to the low number of hydrometry stations in Iran and the lack of continuity of sediment smapling and measuring in many existing stations, on one hand the exact amount of sediment load in many rivers in the country is not available and because of differences in climatic, hydrological and topographical conditions in the country, on the other hand, the preparation and calibration of sediment rating curves for different regions, is unavoidable. The current study was therefore carried out for preparing and improving the accuracy of the suspended sediment rating curve in hydrometry stations located on Telvar and Cham Shor Rivers in a part of the Sefidrood Watershed in Kurdistan Province. To achive the study purpose, sediment rating equation was used as a base equation and then the data were separated using effective factors on sediment transport including hydrological and climatic factors. The models were then extracted from the data series and finally 12 statistic indicators were applied to select the optimal models. The results showed that the M6-9 model (based on separated data considering high/low flows and hydroclimatic seasons) in Hasan Khan and Shadi Abad Stations and the M9-4 model (based on separated data considering hydroclimatic seasons and classified flows) in Dehgolan Station were selected as the best models. The suspend sediment loads based on total and optimal models were estimated by an average 73.32 and 34.20% lower than observed values in three studied stations. Referring to the results, the data set separation for different conditions of precipitation and flow leads to data homogeneity to the extent required to preparing sediment rating curve with a higher accuracy. Results also confirmed that the natural delays in rainfall and flow conditions with the complexity of temperature and vegetation, causes the data separated into hydroclimatic seasons may be more effective than those separated into the main seasons on increasing the accuracy of sediment rating curves.