Based on the method combining statistical analysis with the compilation of historical archives

this article makes an investigation of the temporal and scale properties of flood disasters that occurred in the Guanzhong reach of Weihe River during the last 400 years. According to the related historical archives

99 flood events were recorded during the period

with an approximate frequency of 4 years. 52 of these floods are classified into small-scale flood

35 into medium-scale flood

8 into large flood

and 4 into catastrophic flood. Three main flood sub-periods are also distinguished. The period from 1600 to 1669 and the period from 1670 to 1859 were characterized by low-frequency floods

with a rising and a relatively level tendency

respectively

while the period from 1860 to 1995

by high frequency floods. Periodical analysis indicates that quasi 3-year is a most prominent cycle and 7.14-year

a secondary cycle

which are supposed to correspond to the 2～7 year cycle of ENSO.