Regional Analysis Low Flows in the Karkheh and Karoon Catchments

Analysis of low flow is one of the important considerations in any water resource project. Meanwhile, as a general idea it seems that flow control is more important than drought mitigation but it is necessary to pay more attention to drought problem in future projects. In this paper, available data for 28 selected watersheds were analyzed and then Flow Duration Curve was drew, and discharge of parameters includes , , ,  and were calculated. Also, hydroclimatic and geomorphologic parameters were considered to obtain the most effective factors on low flow. With using Principal Component Analysis from between 21 effective parameter on low flow, factors that showed lowest correlation was selected. The most effective factors were: average slop of the watershed, area, average altitude of the watershed, compactness coefficient and slop of main channel which illustrate 80.1 percent of variation of data. Meanwhile, obtain relation between low flow and watershed characteristics, regional analysis with multivariate regression was carried out. Results were compared with data of 9 control watersheds to evaluate accuracy of the model which showed these models were significant (at 99% level).