Autographic rain-gage networks are designed to provide the density and distribution of stations so that characteristics of rainfall events both in time and over the region concerned can be determined with sufficient precision. The conventional rain-gage network design is simple random sampling, correlation of functions, and regression thechniques. All procedures in generalized and theoretical approaches require some knowledge for spatial correlation of rainfall processes. In this regard, Kriging method, may fully define this spatial correlation. Therefore, the location(s) of the additional rain-gage(s), in an existing network, can be optimized on the basis of the estimated variance. The intensity- duration- frequency (IDF) curves from 64 autographic rain-gage stations in Iran were used in this study. One-hour (60 min) duration, ten-year recurrence P60,10, a key entry to IDF curves, was used to analyze the adequacy of the present autographic rain-gage network. The results showed that at least six more rain-gages are needed for reducing the relative CV from the initial value of 100% to 40%. Three of them must be added in Isfahan, two in Kerman, and the last one in Sistan-Baluchestan provinces. Application of this procedure for the other entry of P60,100 verified the adequacy of the new proposed network. However, the performance of these six additional rain-gages needs to be evaluated over time, using their real IDF curves.

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