In this study, using a two-dimensional hydraulic analysis model at the confluence of the rivers RMA-2 variables were analyzed with respect to the topographical characteristics of the confluence. Compare the results of velocity change of flow characteristics was an average increase of 4.5% compared to the frequency in 100 years 200 years frequency, end point of the maximum flow rate caused by the flow rate was analyzed to shorten the average level of 13.4%. In the analysis of the geomorphological factors and flow characteristics the ratio of the width of the river was high correlation to 0.98. Most of the flow characteristics and factors were analyzed to exhibit high correlation than 0.96. The maximum flow rate of the confluence is high and the correlation of approximately 85% of the flow rate , the flow rate area are found to exhibit a correlation of 86% in the flow ratio. Multiple regression analysis correlation crossing the street caused a maximum flow rate results from higher to 0.997. Inflow angle and width ratio, curve ratio, using the argument of the bent flow characteristics of the flow rate of correlation and multiple regression analysis revealed merging portion end distance is lowest with 0.805.