338 



FIRST YEAR SCIENCE 



downstream side of one curve approaches the upstream 

 side of another and even cuts into it, thus causing the 

 river to desert its curved path and 

 straighten itself at this point. The 

 old deserted winding looks something 

 like an oxbow, and when filled with 

 water, is called an oxbow lake. Some- 

 times the meanders are artificially 

 straightened, as has been done in the 

 lower Rhine valley, and much arable 

 land reclaimed. 



In time of flood, when a river 

 spreads over its flood plain, the ve- 

 locity of the water is checked outside the channel and 

 some of the sediment it carries is deposited. The most 

 sudden check in velocity occurs where it leaves the 



THE MISSISSIPPI AND 



SOME OF ITS ABANDONED 



MEANDERS. 



LEVEE ALONG THE LOWER MISSISSIPPI. 



channel, so more material will be deposited hexe than 

 elsewhere on the flood plain. The banks of the channel 

 will thus be built up more rapidly, and the flood plain near 



