194 



LAND DRAINAGE 



255. Muck or swamp areas. The muck soils vary 

 greatly in depth, the range being from a few inches to 



FIG. 87. To show how springs may occur on slopes, as mentioned in 

 paragraph 254. Water sinking through soil S is deflected by the 

 layer of clay or hard-pan /, and caused to appear at the surface at 

 a, and to saturate the surface as far at least as 6. 



many feet. When the area does not exceed forty to eighty 

 acres, and when it lies adjacent to a fairly deep natural 

 waterway or to a good open ditch, the drainage needs and 



FIG. 88. Sectional view of soil and rock formation, showing the under- 

 ground movement of water and the position of resulting wet areas 

 on the surface. In addition to the springy places, the soil is kept 

 wet by the seepage of water along the top of the compact subsoil. 

 This figure also illustrates the reason for locating a cross drain above 

 the springy area in order to effect drainage. This method cuts off 

 the water supply. (Fippin, Cornell Reading Course.) 



