1 68 



ENGINEERING FOR LAND DRAINAGE. 



supposed to have been run first and computed and the 

 necessary blank lines left for the subsequent cross- 

 section work. 



FORM OP NOTE-BOOK FOR OPEN-DITCH SURVEYS. 



Sta. 



+ s. 



H.I. 



~S. 



Elev. 



G.L. 



C. 



Cut. 



R. 

 Cut. 



L. 



Cut. 



Distance 

 Out. 



Cu. 

 Yds. 





R. 



L 







Right. . . 



Left 



I- 





... 





. . 



. . . 



Knowing grade, center cut, bottom width, and side 

 slopes, set up the instrument and obtain the H. I. from 

 center hub or from the nearest bench-mark. If the 

 ground is level each side of the center, the distance out 

 from the center for slope of i to i will be J bottom 

 width plus center cut, for slope of i|r to i will be ^ 

 bottom width plus i| times center cut, etc. For 

 ground higher or lower than the center, take a level 

 at an estimated distance, find elevation, subtract from 

 it the grade-line elevation and obtain cut. Use this 

 cut instead of the center cut as above described, and if 

 the computed distance out corresponds with that meas- 

 ured, drive the slope stake and record the cut and 

 distance out in their proper place in the book. If not, 

 move the rodman out or in until the proper point has 

 been found. The rodman measures the distance out 

 with his rod and drives the stakes as directed. It is 

 good practice to set a side hub on the right-hand side 

 for the use of the contractor while constructing the 

 ditch, since the centers must all be destroyed, but a side 



