Regional Analysis of Low Flow by Hybrid Method in Mazandaran Province

Drought is one of the oldest natural calamities which has been known by human. Analysis of low flows is a method for estimating the hydrologic drought in the reigns which don’t have enough data. This study evaluates hybrid method for estimating low flow with index low flow method. The first, all the stations in case study reign was investigated and 24 suitable hydrometric stations were chosen. Then, low flow series with duration 7 days were estimated and was fitted distribution function suitable (log pyrson III) and calculated different return period. Case study was divided in index low flow based cluster analysis and in the hybrid method based area. Then low flow regional method was determined based both method and compared using train and error. Result show that hybrid method enjoys high degree as a compared to index low flow and is recommended in station that haven’t suffusion data.