A glacial stone seawall is an alternative to a concrete or steel bulkhead seawall. During construction, a layer of geotextile or gravel is laid along the shoreline and then covered with layers of glacial stone, which slopes gradually to the lakebed and mimics the profile of a natural shoreline. The stones acts as structural protection, and the geotextile or gravel prevent erosion between the stones. The Indiana Department of Natural Resources has very specific requirements for what comprises “glacial stone”. To qualify as glacial stone, the rock used must be rounded stones that meet all of the following criteria:
- Produced by glacial activity
- No individual stone weighs more than 120 pounds
- At least 90% of the material should be able to pass through a 12-inch sieve
- Not more than 10% of the material should be able to pass through a 6-inch sieve
How does a glacial stone seawall help promote healthy lakes?
- Water can flow over and into spaces between the stones, which dissipates wave energy and helps prevent erosion.
- Less erosion results in clearer lake water.
- Glacial stones deter muskrats from damaging your shoreline and lawn.
- Glacial stone provides shelter for aquatic insects, which are food for young fish and in turn can increase fish diversity.
- Rooted plants can grow in the spaces between the stones, providing a natural and beautiful shoreline.
What special considerations are there with a glacial stone seawall?
- When constructing a glacial stone seawall where there was previously no seawall, you will need to apply for a permit and must abide by the restrictions of Indiana’s shoreline classification system (as described in the Permitting Information section).
Glacial stone seawalls must be installed properly to maintain long term protection.
You should contact a contractor if you plan to install a stone seawall.