تحلیل منحنی فروکش اصلی دبی روزانه جریان در رودخانه نیرچای اردبیل

Analysis of river flow master recession curve is a way to assess the occurrence of hydrological drought. The purpose of this study was to inverstigate the master recession curve preparation of daily flow discharge. The master recession curve represents the nature of flow discharge, flow contribution sources and flow recission through the river. The shape of master recession curve used to analyse the hydrologic regime, watershed response and groundwater contribution in river flow discharge. The daily flow river of Nirchai watershed have been used in this study through a 36-year of recorded data. The MRCs in different regression equations (Linear, Exponential, Logharithmic, and Multinominal types) were extracted using a Visual Basic program (Posacev 2006) in excel environment, The constant coefficients and curve slope were defined and then, the coefficient of determination of different MRCs were calculated. Based on the results, the best MRC regression were selected (R²=0.91). The curve slope and constant values were estimated to be -0.07 and 0.443, respectively. These coefficients and indicates and its comparisons in different rivers can be used to investigate the hydrologic regime of the watersheds in different conditions.