Slope/Sheet Erosion

[butch1954]

Problem is sheet erosion on lake front property. House is 140 feet from sea wall. Sheet erosion is undermining the seawall. Lot is 128 feet wide and on a 30% slope toward lake. What is the best way to manage the sheet erosion. I am in Middle Georgia where the soil is clay, so little absorption is taking place. I have thought about french drains, but believe I would have to leave them open as the clay covering would let little surface water penetrate. Any ideas would be appreciated. At this time, no idea is a bad one !

 

[gbam]

Couple of Questions:
Is the R/O from onsite or offsite source? If offsite can it be diverted and/or captured then conveyed in open channel towards the lake?

Is the slope highly Vegetated at this time? If not would adding or densifying the veg help?

Or would Terracing with retaining walls be economically viable? This would decrease that 30% slope ecentially slowing the velocity and may be appealing to the owner. If a number of drops are not economically viable then maybe use larger drops. But that 30% grade can be tough to work with.

First, a discharge will be needed to conduct any calculations in either onsite or off site condition. Then calc a stable slope for the specific soil type, d50 etc... Stable slope analyses can be found in many sed transport texts.

Possible a combination may solve your problem.

 

[bussp]

If you would have to use a french drain system, consider filling the trench above the drain tile with gravel, toped by a filter fabric, and then some top soil on the top 4".