Autographic rain-gage networks are designed to provide the density and
distribution of stations so that characteristics of the 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
techniques. All procedures in generalized and theoretical approaches require some knowledge
for the 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 intensityduration-
frequency (IDF) curves from 64 autographic rain-gage stations in Iran were used in
this study. One-hour (60 min) duration, ten-year recurrence 60
P10 , 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 60
P100 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.