Pond dredging with a trash pump

unimog_jason · Feb 17, 2009

Hello Everyone,

My father inlaw wants to deepen his pond and doesn't want to pay for a dragline. His pond isn't very big but has 2-3 feet of dead organic sludge on the bottom, if you step off the boat you'll be up to your waist in goop.

Has anyone here ever tried doing this with a trash pump? Just curious if anyone has any recommendation on the pump size. I was thinking 4" minimum and maybe 6" but I see even a 4" can move a lot of water in a very short period of time.

One issue we'd be up against is that the pond if the lowest point in the area and it's very likely we couldn't pump it far enough away to keep at least some of the sludge from running back into the pond. One solution I was thinking of was to dig a big pit away from the pond and pump everything in to it and let the heavy stuff settle out. I'd dig a ditch to drain back into the pond and lay down some straw bails with filter cloth to keep some of the finer dirt and debris that didn't settle out from getting back into the pond.

Does anyone have an experience or wisdom they'd like to offer?

Thanks in advance,

Jason

aczlan · Feb 17, 2009

My grandfather dredged a bay out (many years ago) with a 3" trash pump that had a 16hp Wisconsin engine on it. He said that it worked well, but a 3" trash pump with a smaller motor that he rented a few years back didnt work at all, he spent more time cleaning it out than he did pumping. So, a smaller engine or pump is not recommended.

Aaron Z

Airic · Feb 17, 2009

Now, I have a small pond but, used a 3" and siphoned to clean out of silt. No pump. It worked far better than expected. The pond sits about 8' above where I had the discharge. The only thing is to not get to aggressive with the silt. I had times that I had to clean out the pipe but, I removed approximalty 3' and it went pretty quick. I would think a trash pump would do far better than siphoning.

GT2 · Feb 17, 2009

unimog_jason said:
Hello Everyone,

My father inlaw wants to deepen his pond and doesn't want to pay for a dragline. His pond isn't very big but has 2-3 feet of dead organic sludge on the bottom, if you step off the boat you'll be up to your waist in goop.

Has anyone here ever tried doing this with a trash pump? Just curious if anyone has any recommendation on the pump size. I was thinking 4" minimum and maybe 6" but I see even a 4" can move a lot of water in a very short period of time.

One issue we'd be up against is that the pond if the lowest point in the area and it's very likely we couldn't pump it far enough away to keep at least some of the sludge from running back into the pond. One solution I was thinking of was to dig a big pit away from the pond and pump everything in to it and let the heavy stuff settle out. I'd dig a ditch to drain back into the pond and lay down some straw bails with filter cloth to keep some of the finer dirt and debris that didn't settle out from getting back into the pond.

Does anyone have an experience or wisdom they'd like to offer?

Thanks in advance,

Jason

Depending on how abrasive the silt is you may find you will wear out the impeller in the pump.
If you have a large quantity it would be better to make a siphon "Y" and use the pump to suck clean water only ( like a gold dredge).

unimog_jason · Feb 17, 2009

The pump would be a rental unit, likely a 4" trailer mount so I wouldn't be overly concerned about the silt working on the impeller plus these pumps would be built to withstand a little abuse.

I could see the silt being a problem if you were to try to do the job with a gas drive Chinese pump, I could see the mechanical seal being the first thing to go.

It seems that 3" hose is big enough to do the job and the more hp you throw at the problem the quicker it will be finished. Certainly good to know these things before jumping in.

Jason