My waterfront was eroding. Although I can't say for sure, I would guess that I have lost close to 1' in the last five years. There are very few acceptable methods available for erosion prevention. Concrete block, railway ties, large cut stone etc are all prohibited, as well as ugly. While the preferred environmentalist method is to just leave the shore to naturally stabilize (it wont), they don't pay my taxes or my mortgage, so I have chosen to use rip-rap rock on a 1 to 3 grade.
For more information see this link from the University of Minnesota.
I started by putting down geo-textile fabric. I used the heaviest grade of landscape fabric available at the local hardware store (Quest Plastics Limited - Platinum 400 Weed Barrier 5.15 oz/yd2). I got the stone for free. A construction company was renting a piece of land close to my house and using it to sift (remove rocks) from top soil. They allowed me to take as many pickup loads of rocks as I wanted. I used 18 pickup loads in all.
The rest of the fun was getting the truck full of rocks (~ 5-6000 lbs) down the hill. I backed down with the winch hooked to a large birch tree. I was able to drive up when the soil was dry.
The next picture is an example of the erosion. You can see that the waves have undercut the shore line, creating a hole. Eventually the soil at the top will collapse. I've since filled in the hole and added rocks on the 3/2 slope.
...develop, race, win!