68 



From the data so far available for floods in the Ohio River \'alley, Fuller 

 proposes as the maximum 24 hour flow: 



Q equals 150 M, where M is the eatchment area in scjuare miles and Q is 

 total cubie feet per second. 



As a result the maximum expected flood How here would be 180,000 cubic 

 feet per second. 



The average flood is given as, Q ecjuals 75 M, which ecjuals the recorded 

 discharge of last March. 



Another method of discussing the question 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 Hood dis- 

 charge may be expected about once in 40 years. 



