Shoreline Erosion Techniques: Riprap



shoreline erosion techniques, riprapWhen you invest in lakefront real estate on a large lake with a lot of boat traffic you may be seeing some signs of shoreline erosion. There are many different methods of addressing shoreline erosion, and the one we're going to focus on in this posting is riprap.
Riprap is rock, plain and simple. There are large rocks at the toe of the riprap wall on the lake bed and a variety of smaller size rocks that make up the rest of the riprap wall going to the top of the shoreline. It's definitely an effective method of preserving your property, and if done right, can be aesthetically pleasing. If done inadequately, it can be a real eye sore. The most common types of rock used are granite and limestone, but I've seen contractors and homeowners use field stone, too. Usually the contractor will taper the shoreline.

riprap, shoreline erosion
You don't want to have a 90-degree wall, obviously. It needs to be tapered not only so the rocks stay in place, but also because it will do a better job of absorbing and deflecting the energy coming from the waves.  It's getting to be more difficult to get state permits to apply riprap because most environmental/natural resource agencies believe the rock can destroy spawning beds for certain fish and disrupt the overall micro-ecosystem existing there.
Riprap can prevent ice upheaval. I've seen it effectively used on Geneva Lake in Wisconsin where ice upheaval causes serious property damage every spring. The rocks used throughout the wall have spaces between them. They don't exactly fit like pieces to a puzzle, and that's good. Those spaces trap the water that comes crashing up against the wall and slows the flow, weakening the impact. In the next shoreline erosion techniques post we will cover biologs.