TLDR: Looking to build a Gold/Muck dredge using Venturi effect. I think I have the pump and nozzle set, looking for guidance on hosing sizes. Or at least confirm my thoughts.

I’ve been reading through the forum, trying to piece together the information I need, with a lot coming from Driver Cody’s posts.

This trash pump seems to have enough power and is affordable. Craistlist and FB marketplace didn’t seem to offer much better options.
https://www.harborfreight.com/3-in-212cc-gasoline-engine-semi-trash-water-pump-290-gpm-63406.html

Going to spend a little extra for a nozzle, I suspect I could make one cheaper, but I like these:
https://www.keene.store/mm5/merchant.mvc?Screen=PROD&Product_Code=SN3
or:
https://www.keene.store/mm5/merchant.mvc?Screen=PROD&Product_Code=SN32

Setup thoughts:
So, I’ll have a 3” trash pump that I’ll put on my floating dock so it can move with me as needed. I’ll probably only need a few feet of 3” intake hose. I’ll have a short 3” discharge hose from the pump that I’ll have to reduce to 1.5” or 2” to the suction nozzle. And then however long 3” hose I need to pump out over the pond bank. From the nozzle, I’ll probably have a 3 to 6 foot 3” pvc pipe to a T joint or something with a 1 to 2 foot pvc capped with about ¾ inch holes drilled for a sort of vacuum end.

Questions:
Does this setup sound feasible? Am I correct in reducing 3” to 1.5 or 2” to the nozzle. I’m guessing it won’t negatively impact the pump? Any difference between 1.5” vs 2” at the nozzle?

Pond details:
I have a little under a ½ acre pond. I’ve been aerating (two bottom diffused) the past 5 years since we bought the property and using bacteria, it has cleaned up a lot. We live in an area with a lot of flat rock, you can find it in all the nearby creeks, and in our ditch by the road. I think the pond has a flat rock bottom. It is very, very solid probing with a measure stick, and is pretty consistently 8 feet deep all way around the pond. It has about a foot or so of loose muck/silt that I think will suck up pretty nicely. I plan to do most of the work in spring/fall when we have excess water and just pump over the bank towards the woods. I’m planning for a several year project. Perhaps later I’ll look at some sort of de-watering. The pond is roughly a triangle shape, so I’ll start at the swimming area point and work my way out over a handful of years.

Kids love the pond, it is right near the house. Would love to clean it up more and get rid of the leeches.

Last edited by blaroche; 07/18/22 11:35 AM.