28 N. J. Mosquito Extermination Association 



This^ of course, does not apply to main channel and storage ditches 

 leading to pumps and tide gates. 



Some of the ditches installed last season drain the marsh for the 

 unusual distance of 700 feet each side, a total of 1400 feet, which 

 would seem to justify the plan adopted. Ditches cut in the cedar 

 stump meadows in 1921 will all be thirty inches in width and the 

 distance between them will average 1,000 feet. 



Ditch specifications of straight sides, parallel at top and bottom, 

 continuing to be found best suited to the purpose, are being main- 

 tained in Hudson County in both stump and clear meadow. As such 

 specifications can be obtained in no other way than by cutting, 

 proposals to use dynamite, received from time to time, have been 

 rejected. 



The new work done in 1920 amounted to 34,523 feet at a cost 

 of $2,504.42. The cost per foot in the cedar stump meadow was 

 10.6 cents and in the clear meadow 2.84 cents, both classes of the 

 work being done by contract. 95,600 feet of old ditches and culverts, 

 of various widths, were cleaned by contract at a cost of $3,496.50 

 or 3.06 cents per foot. 35,000 additional feet of old ditches were 

 cleaned by our own men. 



The operation of two electric centrifugal pumps, one of twelve 

 inch diameter, serving 800 acres, and one of six inch diameter, serv- 

 ing 150 acres, installed in the low-lying Frank Creek territory several 

 years ago, was continued with the same degree of efficiency that has 

 marked their use from the beginning. They were run twenty-four 

 hours per day at the beginning of the season to draw off the winter 

 accumulation of water, after which they were operated from day to 

 day as required to maintain a sufficiently low level of water in the 

 ditches. 



The commission's experience with the use of pumps justifies the 

 recommendation of such equipment for the control of low-lying and 

 diked areas not served by tide gates or in the case of tide gates not 

 functioning for a long enough period on the ebb-tide to sufficiently 

 lower the head to satisfactorily drain the distant sections of a territory 

 and, in fact, on any area where the action of a drainage system is not 

 rapid enough to remove all the water from the surface and pools 

 in time to prevent emergence. The twelve inch pump referred to, 

 running full time will discharge 7,500,000 gallons in forty-eight hours 

 at the average load, which would mean safety in the case of breeding 

 approaching the pupal stage over an area containing 1,000,000 cubic 

 feet of water. 



