64 N. J. Agricultural Experiment Station, Bulletin 348 



and the natural drainage water is removed by tide-sluices or even by 

 pumps, and require on that account a larger amount of drainage the 

 extra amount being necessary in cutting outlets for the primary 

 system. 



The estimated requirements range from 90 to 600 linear feet of 10 

 by 30-inch ditching, or its equivalent, per acre. As a matter of fact, 

 only rarely is the former figure practicable and then under especially 

 favorable conditions, and never on the New Jersey salt marsh has 

 the latter figure been reached. It seems probable that between 200 

 and 300 feet is the real average. To this must be added an amount 

 of hole filling and shallow spurring which will add about 10 per 



Fig- 33- Small salt holes are filled with sod taken from the ditches. 



cent to the acre cost. Fortunately, large portions of the salt marsh, 

 particularly in the southern part of the state, are so low-lying and 

 open to the tide as to be swept by every tide which is a little higher 

 than the ordinary, and are on that account so free from breeding as 

 to require no drainage. In a given area which includes a consider- 

 able amount of this kind of land, the required number of feet of 

 drainage per acre will be materially reduced. 



The plan of trenching has not undergone marked changes. By 

 1912 two general plans were in use — the first of which might be 



