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AGRICULTURAL ENGINEERING 



Bulletin 78 of the Iowa experiment station. A coefficient of 

 roughness of .03 has been used and they are for ditches having 

 the sides with slopes of one foot horizontal to one foot vertical . 

 The ditches are not to run more than 8-10 full, where the 

 capacity is mentioned. Above the upper heavy lines in 

 the table the % inch standard of water for 24 hours is used ; 

 between heavy lines the J^ inch standard; and below the 

 lower heavy lines the }/ inch standard. 



Number of acres drained by open ditches. 

 Depth of water 5 feet. Depth of ditch at least 6^ feet. 



