Duty of Water in Cranberry Culture 221 



When it is protection against frost which is required, the 

 marsh must be given as much as 4 to 6 inches of water on the 

 level in nearly as many hours. To do this will require a stream 

 of 1 to 1.3 cubic feet per second per acre. But when the flood- 

 ing is to destroy insects, the haste need not be so great ; while 

 for winter flooding, a relatively small stream will answer the 

 needs, as six weeks, if need be, may be taken in the flooding, 

 and as the ground-water surface around the marsh is usually 

 above the marsh itself, the loss from seepage is small, as must 

 also be that by evaporation during the winter. 



