[Stonehenge]

Sorry about the blurriness of this pic - must've jiggled the camera....

So here's the scenario - the client has a spring-fed pond. It's current dimensions are approx. 240' x 90'. At one end he wants a big waterfall. Right now the water level is about 2-3' below the surrounding grade, and he wants the waterfall 5-6' above grade, constructed of stone. And he wants the waterfall partway into the pond, where the water level right now is about 12-18" deep, with a layer of soft mud beneath (unknown how far down it's soft mud - it was only recently dug).

What would a recommendation be for a footing or base for a stone structure large enough to make a waterfall like this? I'm thinking the structure will need to be at least 10-12' in diameter at the bottom, to have a decent sized waterfall at the top.

[Stonehenge]

Ooops. Forgot the pic...

[Paul]

You must be ready for lots of digging

There are a couple of ways to support this, I would start with excavating and damming til I hit good soils or dig 3' -5' wider than the base of the falls. Then using heavy fabric(woven) I would install 12" of 3" stone compacted in 6" lifts. You could build the falls from there if soils are good If not I would use gabion baskets, say 3'x6'x1.5' wired so they would extend 3' past the structure. That should hold up even a solid boulder falls.

[Stonehenge]

Cool. I'm worried about hitting good soil - I may hit water before I hit firm soil. If that is the case, can the gabion baskets be used like a floating footing? Hooked together, able to shift and settle as they need to?

[Paul]

The gabions should hold up even under not so firm soils, they will spread the load out better than footings.