THE MONTHLY BULLETIN. 461 



before locating drains the subsurface conditions must be looked into 

 with great care. This simple fact is mentioned here because according 

 to those who have been conducting drainage investigations it is very 

 frequently overlooked. On the other hand, if the injury comes directly 

 from below, by the rise of ground water, it is plain that drains must 

 be large enough and deep enough, and, if of tile, so carefully laid as to 

 both alignment and grade, that they will not clog, but will hold the 

 ground water low enough to give ample feeding room for plant roots, 

 and generally to prevent the rise of water by capillarity and the conse- 

 quent accumulation of alkali on the surface. In damaged irrigated 

 fields experience has shown that 6 feet is about a minimum depth for 

 tile drains. 



"Where the adverse condition of excessive moisture has obtained suffi- 

 ciently long to result in an excess of alkali, it is evident that in addition 

 to drainage, assuming the natural precipitation is not sufficiently heavy 

 to accomplish reclamation within a reasonable time, surface flooding is 

 necessary to wash out the excessive salts. Sometimes both drains to 

 intercept lateral percolation and drains to lower the ground water 

 coming up from below are necessary in the same field. Again, where 

 it is not practicable to place drains deep enough to collect water press- 

 ing up from below, drainage engineers consider it feasible to excavate 

 pits 4 feet or more deep at intervals directly beneath the drains, which, 

 when filled with gravel, readily carry the water up to the level of the 

 drains. Occasionally, when water seeps laterally through gravel before 

 reaching and causing injury to a field, collecting or "relief" wells in 

 the gravel are sunk and connected to the drainage system. Where 

 drainage waters can not readily be discharged by gravity it has been 

 found feasible to collect them into sumps, from which they can be 

 pumped into irrigation canals or other surface channels lying above the 

 level at which it is desired to maintain the ground water. 



Drainage Experiments in Other States. 



Since about 1901 the Irrigation and Drainage Investigations of the 

 Department of Agriculture have been conducting drainage experiments 

 in the western states, until recently mostly under the immediate direc- 

 tion of Mr. C. G. Elliott, who for some years was Chief of Drainage 

 Investigations. Experiments conducted near Fresno under the direc- 

 tion of Dr. Samuel Fortier, Chief of Irrigation Investigations, will form 

 a later subject in this paper, but before taking them up it may be of 

 interest to cite some of the results obtained elsewhere. Only brief 

 mention will be made of such results as are cited, because the experi- 

 ments are described in detail in Farmers' Bulletin No. 371 and in a 

 reprint from the annual report of the Office of Experiment Stations for 

 1910, entitled "Development of Methods of Draining Irrigated Lands." 



Eleven separate drainage experiments were carried on in Utah from 

 1904 to 1908, with some of them still in progress. A few of these only 

 will be mentioned. 



