Regional flood frequency analysis

Design flood estimation in various projects such as watershed management plans, flood control, design of structures such as river water, overflowing dams and paragraphs dirt roads and underpasses of major importance. One of the common methods to estimate the flow rate, is the regional analysis. The aim of this research evaluating regional flood analysis inNorthern and Razavi Khorasan provinces. The Stations was used to fit the data with a timeperiod of 30 years, homogeneity test statistics test was performed. Results indicate that best statistical distribution was pearson typeIII distribution. Then Physiographic characteristics ofthe basin were collected and determined. Then homogeneity test for the basin in eachprovince and once for entire study area was used by method of cluster analysis. method Multiple regression was used to determine the relationship between the pick flood at differentreturn periods and predicators. Ward method showed better results compared with nearest neighbor and it give two groups, that regression cofficients for zone1, 0.99, zone2,1 and entire zone was between 0.89- 0.95. In general, the overall results show that the correlation coefficient between the rate of return in different physiographic characteristics of selected stations in Zone 1, Zone 2 and the whole of the area, perimeter, main channel length and focus time are important factors affecting in the basin.

کلیدواژه ها:

Regional flood analysis ، regression methods ، Spss software ، northern and Razavi khorasan Provinces