assessment of empirical methods of runoff estimation by statistical test (case study: banadaksadat watershed, yazd province)

runoff estimation resulted from precipitation is the basis of more study in various develop and exploit design from water resource, then its measure and calculation due to environmental bottlenecks, always have a plenty problem. as a result of the importance of output runoff estimation and flood volume in watershed for the sake of country integrated watershed management in this study tried to 9 empirical methods of runoff estimation implemented in banadaksadat and this provided result with observation runoff from hydrometric station in watershed outlet have been evaluation by paired t-test, md, bias, re and rmse tests then selected best model in banadaksadat watershed to runoff height estimation that it’s have a most efficiency and precision. after preparation of necessary maps in gis environment and statistical test implementation in spss software, result showed that lacey method with md, bias, re and rmse value 0.016, 0.007, 4.36 , 0.026 respectively and also no significant difference with observation data in 95%confidence level, with runoff height equal to 1.53 cm, 2.29 mcm runoff volume and 18.79%runoff coefficient , determine the best empirical model to runoff estimation in the case study. the sensitivity analysis using excel software was used for lacey model to determine the influential reachs, according to the get result, f/z parameter in 6-8, 8-10 and 18-20 reachs have a most effect in the model output.