146 IIIBIGATIOX. 



ter of the vegetation they bear be totally changed. An 

 undrained meadow may be thus, by irrigation, changed 

 into a marsh, and good, though scanty grass be replaced 

 by useless marsh sedges and rushes. Sloping lands may 

 need drainage as much as level lands. Hillsides that have 

 been brought under irrigation, have sometimes discharged 

 their surplus waters at a lower level, where they have 

 gathered and changed a portion of the surface into a 

 quagmire, until drains have been constructed to remedy 

 the evil. 



Again, there are cases in which, by a judicious system 

 of drains, a swamp may be reclaimed, and the water, 

 which had been previously a hindrance to cultivation, 

 may be gathered into ditches and used to irrigate a 

 meadow, and yield bounteous crops. Such a case, which 

 actually occurred, may be profitably described. It was a 

 hill-side of fertile clay soil, resting upon a clay slate, 

 from which the soil of a level flat at its foot had been 

 originally derived. Abundant springs broke out upon the 

 hill-side, and after forming marshy spots around them, they 

 disappeared until they again broke out at the foot of the 

 hill, where they gathered and formed a dangerous and im 

 passable swamp. Here were 30 acres of land rendered 

 worthless, and a dangerous trap for any stock that might 

 be tempted to trespass upon its treacherous surface. Hun 

 dreds of similar tracts exist where there are hills and 

 valleys. 



The reclamation of this tract was a very simple mat 

 ter. Its outlines are shown at figure 73. A drain was 

 cut near the foot of the hill. See a. It was necessary 

 to take this drain to a depth of seven feet before the 

 heaviest springs were cnt. At this depth, a flow of water 

 was reached which nearly filled the ditch, and furnished 

 a large stream. The drain was placed, with a view to ir 

 rigation of the meadow, a few feet above the level of the 

 flat. It then formed a supply canal from which the flat 



