74 N. J. Agricultural Experiment Station, Bulletin 348 



When the construction of the dike began, a trench 10 inches wide 

 by 20 inches deep was cut along the Hne to be occupied by the struc- 

 ture, and the sods taken out utilized in making the dike. A row of 

 sods composed of pieces approximately 10 inches wide, 12 inches 

 high and 26 inches long was laid in each side of this trench with the 

 grassy ends out, enclosing a space 20 inches wide. Mud was then 

 tamped into the trench until its surface was flush with the upper sur- 

 face of the sod layer. Then another layer of sod composed of pieces 10 

 inches wide by 12 inches high by 24 inches long was placed on top 

 of each of the other two layers. Again the grassy ends were out 

 but the ends of the upper layer were 6 inches nearer the dike center 

 than were the ends of the lower layer. The central cavity thus 

 formed was tamped full of mud. Then a third layer of sod was 



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Fig. 41. Tide-gate construction. (Courtesy of the Essex County Mosquito 

 Extermination Commission). 



placed on the second in a similar fashion with a similar approach 

 to the center. The space formed between the two parts of the lay- 

 ers was tamped full of mud. In some cases the dike thus constructed 

 was covered with a layer of sod while in other cases the crest was 

 simply rounded up with mud. 



The sod and the mud for making the dike came from the prelim- 

 inary trench and from a supply trench which was dug inside the pro- 

 tected area about 8 feet from the base of the dike. In some cases 

 a supply trench was dug on each side of the dike. In every case the 

 supply trench was of uniform width, did not exceed 3 feet in depth 

 and was properly connected with adequate outlets. 



