In this study, flow duration curves with regression analysis method in the Eastern Black Sea Region by using available some flow observation station data, in the physical meaning, on the earlier unmeasured points, to make flow rate estimation, finding of them were studied. Initially, flow rates relative to monthly and yearly 5%, 50 and 95 exceedance probabilities from flow continuity values in
... [Show full abstract] all available daily data for 16 flow observation stations were found by using developed MS Excel Macro code. After that, the indicators of the characteristics of the region, average catchment area (A), average precipitation of area (P), average elevation (H) and average slope (S) independent variables were calculated for each station by geographic information system software. The determination of these independent variables originated from the study made by Risley et al. (2008) for the State of Oregon in USA. Regression equations were developed to show the effects of monthly and yearly 5%, 50 and 95 exceedance probability of for each determined independent variable on the dependent variables that flow rates which against to them. Equations only produced for 14 stations of 16 stations and other two stations have been left for validation. These regression equations gave the flow duration curve values that estimate monthly and yearly 5%, 50 and 95 exceedance probability in the regional perspective. In some regression equations, the slightly effective independent variables extracted. Finally, regional flow estimation was made from the obtained equations and the estimations compared with earlier studies by different methods in the literature. Upward determination coefficients obtained from one of two stations which used for validation has a higher number of years with daily measurement that caused the opinion obtained that by increasing numbers of years with data could be present better representation of equations for the region.