According to the report of the Thai Meteorological Department presented the annual rainfall totals in 2011,
this study determined that the flood frequency analysis using annual maximum daily flows for the three
periods as the historical (1980–2004), near future (2015–2039), and late future (2075–2099) periods, was
investigated by the three flow stations at Nakhon Sawan and upstream of Sirikit and Bhumibol dams [10].