Does anyone have knowledge of engineering/constructing a berm/ levee/bund/dike?

Question

I want to build a a flood protection barrier but I know you cant just make a mound of earth as this will still leak water.What depth should an impermable core be?Any engineering advice appreciated.

Answer 1

Not sure how high you want to build it. For a water depth greater than 2 feet you need something professionally done.

If you are building on soil, I would suggest digging a 4ft wide trench to a depth of about 2 feet. You must dig down into the impermeable clay layer if there is one. Hammer into the base of the trench 2 rows of 6ft wooden stakes to depth of 2 ft, rows about 2ft apart, stakes about 2 ft apart along the row. Construct 4 ft high wickerwork fence along each row. Infill with rubble to top. In the trench on the flood side of the wickerwork fence, the rubble should be mixed with clay. Then cover with soil over the tops of the posts, and filling the trench so that each side has angle of slope of less than 45deg. Seed slopes with grass so that the roots will bind the surface. You will now have a 2ft high flood protection barrier using natural materials (for temporary floods). If this barrier is permanently adjacent to the water it would crumble in time, you would need a stone or concrete dam.

If you haven't got an impermeable clay layer below the topsoil, you would have to dig even deeper. Leaks will develop if the pressure of the water seeping under your barrier can lift your barrier, so your barrier needs to be heavy. A lot depends on the soil profile, so you should first take core-samples to investigate.

If it fails, don't blame me. I am not a civil engineer.

Answer 2

Just watch the beavers!

Answer 3

http://www.usbr.gov/uc/feature/pv_dam.html

I hope this helps you...