25 



In the summer of 191 4, the Commission decided to do future 

 ditching with its own forces and to build a ditching machine 

 after the plans of the Chief Inspector. The machine was com- 

 pleted in the fall and after some trial was moved to the east side 

 of the Great Egg Harbor River, where 48,800 lineal feet were 

 dug at a cost of % cents per lineal foot. In the preceding spring 

 the Commission had adopted the policy of digging its spur 

 ditches, clearing ditches and filling depressions with its own 

 laborers instead of by contract. It was found that ditches 20 

 inches deep and 7 inches wide were as suitable for spurs as the 

 ditches 30 inches deep and 10 inches wide. One-man spades 

 were accordingly built and a material saving affected, as the cost 

 of these ditches is only y 2 to cents per foot against 2 to 2^2 

 cents per foot paid to the contractor for the larger ditches. The 

 cost of this supplementary drainage must always be included, as 

 drainage is seldom effective without it. The amount of supple- 

 mentary drainage necessary for complete safety varies greatly, 

 depending on the kind of meadow, number and depth of holes, 

 etc. A meadow with few or no holes and depressions but on 

 which the water stands in large shallow pools, requires very little 

 "spurring," as the main ditches satisfactorily drain the meadow. 

 Where depressions are numerous and deep a large amount of ad- 

 ditional ditching is required, as seepage and evaporation are 

 not sufficiently rapid to dry them up completely. Even a sixteenth 

 of an inch of water left in a pool is sufficient to preserve life in 

 the mosquito larvae for several days, and all pools must therefore 

 be drained absolutely dry. 



The amounts given here and in our reports, therefore, as 

 being expended on salt-marsh drainage, include not only the main 

 10 x 30 inch ditches but also a large amount of 7 x 20 inch 

 ditching, the filling of depressions and the cleaning of ditches. 



Last summer a second ditching machine was built and started 

 on the meadows north of Absecon. Up to December 1st, 191 5, 

 a total of 874,000 lineal feet of ditches 10 inches wide and 30' 

 inches deep had been dug by the machines, partially draining 

 an area of 5,150 acres at an average cost of $2.33 per acre, in- 

 cluding repairs and depreciation of equipment. Of this 5,150 



