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The Flood Studies Report, published in 1975, is used in relation to rainfall events in the United Kingdom.〔http://nora.nerc.ac.uk/5964/1/IH_094.pdf〕 It has since been replaced by the Flood Estimation Handbook, but the method can still be used. ==Calculation procedure== It is possible to use the FSR to predict the depth of rainfall from a storm of a given duration and return period. The FSR includes values for two key variables mapped across the UK: the M5-60 minutes rainfall, and the ratio "r". *M5-60 minutes rainfall is the expected depth of rainfall in millimetres (mm) from a storm lasting 60 minutes (1 hour) with a return period of 5 years (hence M5). *M5-2 days rainfall is the expected depth of rainfall from a storm lasting 2 days (48 hours) with a return period of 5 years. *The dimensionless ratio "r" is the M5-60 minutes value divided by the M5-2 days value. *Factor Z1 is found from the values of M5-2 days and "r". *Factor Z2 (the growth factor) is found from the M5 rainfall depth, and depends on the return period. *The Areal Reduction Factor (ARF) takes the catchment area into account. For small catchments (below 1 km2) the ARF is not required. To find the depth of a rainfall of duration D and return period T at a given location in the UK, the following should be carried out: # Find M5-60 minutes rainfall depth and "r" for the location using FSR maps. # Divide this rainfall depth by "r" to get the M5-2 days depth. # Multiply the M5-2 days depth by factor Z1 to find the M5-D depth. # Multiply the M5-D depth by factor Z2 (the growth factor) to find the MT-D depth. # Multiply the MT-D depth by the Areal Reduction Factor (ARF). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Flood Studies Report」の詳細全文を読む スポンサード リンク
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