This article on the same topic is worth reading: How the demand for sand is killing rivers http://www.bbc.com/news/magazine-41123284 http://www.bbc.com/news/ma

This article on the same topic is worth reading: How the demand for sand is killing rivers http://www.bbc.com/news/magazine-41123284 http://www.bbc.com/news/magazine-41123284