DEAIISTAGE OF lEEIGATED LAND. 



17 



always be provided. This device costs little and occupies but small 

 space. If desired; the top section may be removed at any time, a cap 

 provided, and cultivation carried on directly over the top. Such a 

 device may also be installed between regular manholes, for inspection 

 purposes. Figure 17, page 22, illustrates the application of observa- 

 tion wells. 



SURFACE INLETS AND FLUSHING WELLS. 



A vertical stack of tile is also useful as a surface nilet and flushing 

 well. Figure 10 shows how it should be installed. The bottom 



Grave/ 



3iee/ Cho/n orZ/vn Bandw/M /fi'ngs 

 t^ssseoes^S and fhdiock 



Surface 



Fig. 9.— Observation well and sand trap con- 

 structed of tile. 



Fig. 10.— Standpipo, built of tile, for flushing 

 drain or to act as surface inlet. 



should be paved with coarse gravel and the top provided with an iron 

 grating and a mound of gravel or crushed stone. Such an inlet should 

 be installed wherever a drain crosses a depression or flat, so that the 

 waste water or storm water may not pond for a suflicient length of 

 time to puddle the soil or "bum" the crop. One of these should 

 also be placed at the i]y)per oii<l of each branch line as is indicated 

 in figure 17, y)uge 22. 



FLUMES. 



Flumes should be providc^d for all canals and ditches that cross 

 iiudcrilrains, and caro should b(5 taken to prevtmt largo quantities of 

 water from flowing across these; drains, ])articularly during the fii-st 

 two seasons after the installation of the latter. 

 7773.3" -Hull. 190—15 3 



