In 2000 the Surfrider Foundation constructed an artificial surfing reef in El Segundo, CA as mitigation for a lost surfing resource. Because it did not improve surf quality and had begun to deteriorate, plans were initiated to remove the reef in the fall of 2008. Phase I of the reef removal process took place during the Fall of 2008 and Phase II of the removal process took place during the Fall of 2010. Read more about this here and here. Also see:
Surfrider Foundation has developed a Policy on Artificial Surfing Reefs.
Surfider Foundation's former CEO Jim Moriarty has written several articles about various aspects of artificial surfing reefs, including this article for The Inertia.
Also see Can artificial surf reefs reduce crowds? by Surfrider's current CEO Chad Nelsen.