Earlier this month, a short video about the Montauk Lighthouse was on NOVA, on PBS, Public Television. It details the process and the people who created a terrace structure to stop erosion of the bluff.
Interestingly, a claim is made in the video that due to the terrace, "We have not lost a wheelbarrow full of sediment off this project."
We find it interesting then that the Army Corps of Engineers claims the bluff is severely eroding and in dire need of a massive new rock revetment. Both things can't be true.
See the video for yourself here:
http://www.pbs.org/video/2365746001/