162 



FARM DEVELOPMENT 



Chains, tapes, rods, stakes, etc. The surveyor's chain, 

 folded, is shown in Figures 63 and 64. Chains are usually 

 four rods (66 feet), sometimes 100 feet in length. 

 The surveyor's band chain of steel is shown in Figure 

 62. It is now commonly used by engineers, being made 

 lighter and more accurate than the steel chain. 



Note books and blank forms. All measurements and 

 surveys should be accurately recorded in such form that 

 they will not only be useful in 

 planning and constructing the 

 drain, but will serve as a per- 

 manent record. If the drain does 

 not work properly, some fault in 

 the figuring or calculations may be 

 found, in which case the records 

 will be useful. Should the drain 

 at any time get out of repair, the 

 original notes may be useful in its 

 repair or reconstruction. Notes of 

 the location of underdrains are 

 especially valuable as permanent 

 records for u se when wishing to 

 the m e u?l ttis te StoS Iocate obstructions in tile drains. 



necessary, corrected. 



Figure 81 gives a form to be used 

 in recording the levels taken in 



rate, even serving as a standard / j , i i r 1 



with which to compare the link nndinfif the DCSt COUrSC for the OrO- 



chain, that its length may oc- ., , . 



be tested, and, if posed drain, as well as the date 

 used in making calculations for its 

 grade and depth. Furthermore, in making the drain, 

 the level is used in checking for the depth of the ditch at 

 various points along its course. An indexed notebook, 

 4x6 inches, ruled as in Figure 82, is a good place to keep 

 the original notes, including the calculations. 



Drainage plats show methods of making drainage 

 maps. A drainage map of a portion of the valley of the 

 Red River of the North is shown in Figure 70. The 



