THE WORK OF RUNNING WATER 



93 



extends to cities and villages as well. Terrible illustrations of the 

 havoc wrought by floods are furnished by many rivers. In the 

 spring of 1897, many thousand square miles of the flood plain of 

 the Lower Mississippi were covered with water, and 50,000 to 60,000 

 people suffered serious loss. In 1881 and 1882 the floods of the 

 same stream and of the Ohio are estimated to have caused a' loss of 

 $15,000,000 and 138 lives. The losses occasioned by the floods of 

 the Ohio alone were estimated at $10,000,000 in 1884, and at $40,- 

 000,000 in 1903. There was a disastrous flood in the valley of the 

 Wabash, and another in the valley of the Susquehanna, in 1904, 

 each causing the destruction of property to the extent of several 

 million dollars. Other similar illustrations are unfortunately too 

 numerous. 



At debouchures. Where a swift stream flows into the sea, or 

 into a lake, its current is checked promptly, and soon destroyed 

 altogether. Its load is therefore dropped, and if not washed away 



Fig. 97. Delta of Lake St. Clair. (Lake Survey Chart.) 



by waves, etc., makes deltas (Figs. 97-101). The delta has some 

 points in common with an alluvial fan. In both cases, the principal 

 deposit is made at the point where the velocity is checked suddenly. 

 In the case of the delta, however, the current is checked more com- 



