Evaluation of Isorainfall Curves Derived from Geostatistical and Correlation Methods in Kohgiloyeh va Boyerahmad Province

In arid and semi-arid regions due to a lack of rainfall and high scattering of rainfall stations, the rainfall distribution estimation among the stations is necessary for the water, soil and flood in this research to study the spatial variations of maximum and pervasive rainfall in Kohgiloyeh va Boyerahmad Province the observational storms (in 35 stations) were collected and studied. In this study 45 storms were selected. To investigate the spatial distribution of rainfall amounts in the methods studied, the observational storms spatial pattern with 4 methods such as kriging, cokriging, inverse distance and precipitation gradient equation were analyzed. The results were evaluated using the comparison of the estimated error of each method. The maximum rainfall were determined using models derived from depth area duration relationships in durations 2,3,6,9, 12, 18, 24, 36 and 48 hours in Kohgiloyeh va Boyerahmad Province. According to the results, correlation coefficients are provided the appropriate values for durations 6, 18, 36, 48 hours. The DAD relationships derived from this method show lover values of percipitation to geostatistical method. This study indicated that the most of storms in cokriging method have lower errors.