Help understanding the potential of a gravity dredge

[Superdum]

I have come to the realization that I need to move more dirt. But I'm one guy with limited resources. I was looking at high bankers and dredges. The cost and time and energy of hauling pumps and fuel or batteries are not appealing to me at all. So I was looking into building a gravity dredge.

Any ideas on how efficient they are compared to other options? Can I move as much dirt as a high bankers or traditional suction dredge? What are the pitfalls involved with a gravity fed system?

 

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[Jason in Enid]

They're not...no...no, and you can only suction from the high point. Dont think of it like dredging, think of it like stream sluicing, without shovels, and with much less freedom of movement. You also need a fairly significant elevation drop, a few feet wont cut it. How much hose are you willing to haul vs motorized dredges?

 

[Superdum]

They're not...no...no, and you can only suction from the high point. Dont think of it like dredging, think of it like stream sluicing, without shovels, and with much less freedom of movement. You also need a fairly significant elevation drop, a few feet wont cut it. How much hose are you willing to haul vs motorized dredges?

There is a pretty significant drop in the stream at this location but it's in the 5 to 10ft range I would guess. I've seen people using 100ft of hose on YouTube but that seems excessive. Do you need that much hose for good suction?

Depth of the water and volume/speed of current is going to dictate the suction power but if I gotta haul 100ft of hose...I'm out. I'll just save up for a self classifying sluice like the keen A52s or a fluid bed.

 

[arizau]

Now that you have decided to save for a "store bought" sluice you might as well build one to use in the interim...many of us have and still use home made sluices, etc. The basic design is simple straight forward and perfectly suited to be built from salvaged materials, etc...building site rolloffs come to mind as a free source for wood.

Good luck what ever you do.