Rainfall is one of the meteorological parameters which plays an important role in developmental projects.
Three, twenty seven, and three recording rain-gauge stations were selected for North, Razavi, and
South Khorasan provinces, respectively. These stations had more than 8 years of record length, end to
2002. All of the recorded storms were digitized. Minimum and maximum storms were 182 and 525 for
Sangan-Khaf and Mashhad stations, respectively. However, all storms were not recorded completely. Yet
no acceptable method could be utilized for re-construction of such storms. Gumble distribution, among the
common distributions, better fitted the rainfall intensities of all stations. Considering 10 year-hourly rainfall
between rainfalls over the vast geographical territory of 3 provinces under study. Nonetheless, no significant
relationship could be derived for (p
map for (p
desired ungaged-point. It was shown that the bias for estimation of rainfall corresponding to any time duration
and frequency for all stations, except one, was negligible.