186 LAND DRAINAGE 



long stake to mark the proper height of bar at that stake. 

 In this position the bar should be nailed to the two stakes. 



245. Checking the bars. After the bars are in place, 

 one should sight over them to see that their tops are in 

 line. The drainage work proceeds from this point in the 

 ordinary way, except that in opening the ditch its edge 

 should not be cut nearer than one foot to the tall stakes. 



246. Grade stakes and finders not needed. As is 

 readily seen, in using such a scheme as that above de- 

 scribed, the grade stake is of little service, and may be 

 dispensed with. When the grade stake is dispensed with, 

 care should be exercised to have the long stakes stand in 

 fair alignment, and one foot back from where it is desired 

 to have the edge of the ditch. The finder is also unneces- 

 sary. Any data may be recorded on the long stake. 



247. For more extensive work. For drains of con- 

 siderable length, and on lands of considerable roughness 

 of contour, the leveling may be done with the hose-level, 

 without rods, but some modifications must be introduced. 

 Under such conditions, it might be necessary to divide the 

 drain, into sections and to level for each section separately. 

 The fall (in surface) for each section might be determined 

 separately. This would most likely result in a break in 

 grade between sections, and it would be necessary to ob- 

 serve the precautions previously indicated regarding the use 

 of silt basins at breaks in grade. It is entirely practical, 

 however, to level and find the fall for each section sepa- 

 rately, and to combine the falls and establish a constant 

 grade for the entire drain or to establish breaks in grade 

 at other than section points to conform grade to the 

 contour of the line of the drain, as in any other case. 

 In establishing grade, proper corrections must be made in 

 passing from one section to another. 



