Breakwater

A breakwater is a offshore structure made to protect harbors and marinas from waves. Protects from wave erosion. It is made by rocks and ruble then big rocks so it doesn't wash away.

"What is Civil Engineering ?." Civil Engineering. N.p., n.d. Web. 8 Jan. 2013. <http://whatiscivilengineering.csce.ca/coastal_breakwaters.htm>

The negative effects of a breakwater is that the protection the walls gives is limited.

"Detached breakwaters - Coastal Wiki." Main Page - Coastal Wiki. N.p., n.d. Web. 10 Jan. 2013. <http://www.coastalwiki.org/coastalwiki/Detached_breakwaters>