DRAINAGE 



143 



water in a meandered lake without consent. Where the 

 area of low land lies along the stream through which 

 the lake discharges its supply of water, it is often prac- 

 ticable to construct surface or tile drains which will dis- 

 charge their water at some point down the stream. 

 Where low areas lie on the side of the lake opposite 

 the outlet, and higher land rises behind them, there is 

 usually no chance for an outlet away from the lake, and 

 owing to these difficulties many of these lands cannot 

 well be drained. Where such areas are large and valu- 

 able, however, they may be drained by a system of 

 dikes, drains and pumping machinery, conducting the 

 water through ditches to a low point near the lake, and 

 then elevating it over the embankments by pumps oper- 

 ated by steam or other power. Large areas of land in 

 Holland have been thus reclaimed from the sea, and 

 much more is now being reclaimed at great expense. 

 The streams which pass through these " Netherlands " 

 are conducted to the sea by means of large embankments, 

 called dikes, and not allowed to overflow their banks 

 and thus spread out over the fields, even in times of 

 floods, so that all of the water that it is necessary to 

 pump out over the embankments is that which actually 

 falls upon the land. These flat lands are so rich that 

 this trouble and expense have well repaid the thrifty 

 people of Holland. As our country becomes more 

 densely populated, the areas which we will thus reclaim 

 will increase. The great irrigation projects of the West 

 are bringing us, also, to see that very large diking and 

 draining projects are feasible and may be profitable. 



Springy hillsides. Since the earth composing hills is 

 often deposited in layers, the water which penetrates the 

 soil on higher portions of the land is often arrested in 

 its downward course by an impervious layer of clay or 

 rock. If above the dense stratum there is a layer of sand, 

 gravel or mixed earth, through which the water can seep 



