68 



From the data so far available for floods in the Ohio River Valley, Fuller 

 proposes as the maximum 24 hour flow: 



Q equals 150 ]\I, where M is the catchment area in square miles and Q is 

 total cubic feet per second. 



As a result the maximum exi^ected Hood flow here would be 180,000 cubic 

 feet per second. 



The average flood is given as. Q eqvu\ls 7o M, which equals the recorded 

 discharge of last March. 



Another method of discussing the ciuestion of future floods is by their 

 expected frequency. For those eastern streams where data has been col- 

 lected for some time it appears that a flood of twice the average flood dis- 

 charge may be expected about once in 40 years. 



