276 THE MOSQUITOES OF NEW JERSEY 



these parallel ditches or filled with sod or other material. In the hole- 

 connecting scheme ditches were run from one hole to another and finally 

 into one or more outlets. It was held that such a plan was most prac- 

 ticable where the marshes were very full of salt holes. Experience since 

 that time has clearly indicated the superiority of the parallel ditching, 

 and the hole-connecting plan has been practically abandoned. 



Fig. lxxxiv. Map showing hole-connecting scheme of ditching. 



Since 1912 Eugene Winship, of the New York City Department of 

 Health, has devised and caused to be installed a large amount of a still 

 different system of salt marsh drainage. It is known as the "Checker 

 Board System" and consists essentially of two parallel systems one 

 superimposed at approximately right angles to the other. Mr. Winship 

 claimed that with so many outlets it is practically impossible for the 

 drainage of one area to become blocked and that the maintenance prob- 

 lem is therefore less difficult. This system has not found favor in New 

 Jersey for three reasons: (1) the cost of the system is much greater; 

 (2) on the meadows treated in this way, the ditches interfere with the 

 use of equipment employed in harvesting hay; (3) mosquitoes are not 

 materially reduced. 



Early in the ditching program it was recognized that the type of 

 outlet was of supreme importance, and recent experience has served to 

 confirm this notion. The greater the tide drop and the shorter the ditch 



