The high water in the Great Lakes, particularly Lake St. Clair, was washing earth off my property. I have a steel seawall installed 10 plus years ago that was several feet above lake level back then. However the Great Lakes have a fluctuation in water level that cycles over 5’ from maximum low to maximum high.
The water level was 1 inch from the top of my steel seawall which is not water proof in any manner. The steel is ribbed for strength with a 4” angle iron bolted to the top to cap and strengthen it all together. The gaps between the wall and the angle iron allow waves to splash up and onto the yard it is protecting.
To prevent the loss of soil through the cap of the seawall in this high water I have removed a shovel full or so of earth from the inside of the wall to expose about 8” of steel. Then I inserted heavy duty visqueen against the steel and backfilled with earth to trap the visqueen. The visqueen and the earth now make the voids in the steel almost waterproof.
I used 3’ strips of visqueen about 30’ long and overlapped them 2’ as I worked my way across the property. I used 3’ wide strips and after backfilling with earth I rolled the excess, about 2’, up and with bricks secured the material on top of the wall. Now if the lake rises again next year I can take some soil, form a berm across the edge of the seawall and wrap the earthen berm with the excess visqueen preventing it from washing away.
Plastic against a mound of earth forms a quick, inexpensive dyke against high water. This is easier, quicker and cleaner than sand bags. Then it’s easier to dispose of when the high water subsides and the berm is no longer needed.