'JXfiti BiU on i^i (Bodke 



if they are stored full during rainy days, the leak- 

 ing helps to maintain the stream-flow in dry 

 weather. A beaver-dam thus tends to distribute 

 to the streams below it a moderate quantity of 

 water each day. In other words, it spreads out 

 or distributes the water of the few rainy days 

 through all the days of the year. A river which 

 flows steadily throughout the year is of inestima- 

 ble value to mankind. If floods sweep a river, 

 they do damage. If low water comes, the wheels 

 of steamers and of manufactories cease to move, 

 and damage or death may result. In maintaining 

 a medium between the extremes of high and low 

 water, the beaver's work is of profound impor- 

 tance. In helping beneficially to control a river, 

 the beaver would render enormous service if al- 

 lowed to construct his works at its source. Dur- 

 ing times of heavy rainfall, the water-flow carries 

 with it, especially in unforested sections, great 

 quantities of soil and sediment. Beaver-dams 

 catch much of the material eroded from the hill- 

 sides above, and also prevent much erosion along 

 the streams which they govern. They thus catch 

 and deposit in place much valuable soil, the cream 



64 



