1 Hi MOSQUITO ERADICATION 



posed dike; the purpose of this is to get a good bond with the 

 earth. Sods are then laid on either side of this core ditch, and 

 the interval between them tamped with mud. Another layer 

 of sods is then placed on top of the first, only a few inches closer 

 together, and more mud tamped in. This procedure is continued 

 until the necessary height is reached. The whole may then be 

 capped with sod or plastered with mud. 



The sods and mud generally are obtained from a ditch parallel- 

 ing the inside of the dike. Sometimes, this ditch receives the 

 flow from the laterals and conducts it to a convenient tide-gate. 

 Sometimes, a supply ditch is dug outside the dike, but, if this is 

 done, care should be taken that it is properly connected with 

 adequate outlets. In order to prevent caving, no ditch, either 

 inside or outside the dike, should be located less than 8 or 10 

 feet from the dike. 



"Some dikes," says Headlee, 1 "have been constructed entirely with 

 mud, but always in places where sod was not available. In such 

 instances, the mud has been scooped from a trench back of the dike 

 (forming a ditch paralleling the work and giving useful drainage), and 

 piled up until a dike of requisite height, with due allowance for shrinkage, 

 had been built, which was 2 feet wide at the top and as broad at the base 

 as was demanded by the normal angle of repose. This type of dike does 

 not withstand the weather or the water as well as the sod type, but is 

 efficient if carefully looked after." 



Dikes vary in size, of course, with the height of the tides. 

 Usually, along the Atlantic coast, they average from 2 to 4 feet 

 high, 2 feet wide at the top and 4 to 6 feet wide at the bottom. 

 The cost varies with the size. Fuchs 2 reports construction of a 

 dike averaging 2 feet high, 2 feet wide at the top and 4 feet wide 

 at the bottom at a cost of 35 cents a lineal foot. 



To protect the dikes against muskrats, brown rats and other 

 rodents which may burrow through and undermine the dikes, 

 it is customary in New Jersey, to insert a piece of chicken wire 

 vertically in the middle of the core of the dike letting it extend 

 down as far as 2 to 4 feet below the surface of the marsh. 



1 "Some Recent Advances in Knowledge of the Natural History and the 

 Control of Mosquitoes," New Jersey Agricultural Experiment Stations, 

 Bulletin 306, 1916. 



2 Transactions of the First Annual Conference of Sanitary Engineers, 

 U. S. Public Health Service, 1919. 



