Rx for ponds silting in.

[patrickg]

As ponds age they often "silt in". I've been told that it is frequently cheaper to just make a new pond than cleaning out an old one B U T I like the location and looks of several (most) of my ponds and want to do some sort of age reversal process. Something that came to mind was using a suction dredge to vacuum clean the silt deposits. Many of you have seen, I'm sure, the suction thingies that archeologists and treasure hunters use to remove sand and other overburden to get to the good stuff. I was thinking of going uphill from a pond and cutting some parallel to each other trenches similar to contour farming. Then fill the trenches with filter material (straw, woodchips,or similar biodegrading soil ammendment.

Then fire up the ole reliable engine driven water pump with a venturi effect suction nozzle and vacuum clean some silt deposits. The idea is to have the stuff that is sucked up go up a hose (2 in??) and pour out on the slope above the contoured ditches. Then according to my fond hopes (hopefully aided by physics - gravity) the silt will be filtered out as the water cascades from filter ditch to filter ditch. Much of the water, after filtration, flows downhill back to the pond, minus that which is trapped in the ditches and or is wetting the filters.

After the pond is restored then the ditches are plowed up/tilled and seeded. Oh yeah, but plowed up and tilled such that a residual saw tooth shape of contours is retained to ****** the water flow and ameliorate the slopes tendency to errode (caused the problem to start with). This saw tooth shape will be likek going down a flight of staire where the treads are tillted back so as to hold some water.

Please do not be gentle. If there are obvious difficulties, don't spare my ego, better to know before than find out after a lot of hard work (even if a lot of it will be from the seat of my tractor).

Patrick

 

[Boondox]

Funny you should mention that. When I check out the muck on the bottom of my pond all I can think of is those old Jacques Cousteau specials where his crew uses those air-driven suction things to suck the muck out of ancient Greek and Roman shipwrecks. As a modern corollary, I've often wondered if a powerful trash pump would accomplish the same thing. Only I never thought of the ditch. Figured I'd just spray it uphill and let the meadow grass filter it all out.

Finally I decided it would be easier to prevent silting than to fix it after the fact. So I installed a silt trap in the stream so only clean water enters the pond. Guess this doesn't really help you, though. Sorry.

Pete

www.GatewayToVermont.com

 

[Bird]

Patrick, of course I don't know; just guessing. I think the idea is good, but that you'd never get the job done with a 2" pump or line, and that you'd better have a really powerful pump or the line will just keep getting plugged up.

Bird

 

[RPM]

I think you'd be surprised ... you could probably get more done with a good trash pump than you'd imagine. It would probably wreck a regular pump though.

Design details and specifications of an 'airlift' as they call them can be found at:

http://www.weymouthdiving.co.uk/equipment.htm

You can do a search on 'airlift dredging' on Google or other fine search engines and get more information.

I guess it depends on what is at the bottom of the pond. If it's just silt, you're probably alright. If it's the usual detritus, then you may be in for some blockages.

Oh yes - one last tip - do it on a windy day. The muck that comes up stinks (and I've only had very limited experience of it!).

Another approach if you can do it is to just drain the pond by breaching the dam (if you have one). Let it dry for a couple of weeks and then get in there with your loader.

 

[MarkV]

Patrick,
One thought I had was to add silt fence to the leading edge of your filter trenches. That would make sure that if things got flowing to fast the silt would not end up back in the pond. You might even be able to get by without the straw in the trenches. Fill one trench with silt and then move to the next.

MarkV

 

[jdkid]

Hi ya
How big is ya pond?? and when is it ment to rain next ?
like another posting maybe let it dry out and then dig it out with a FEL /backhoe or ya may think this sounds funny but what about a sepic tank cleaner more suited to moveing stuff like that . like bird, i don't know if 2 inch would handle it .hang on in Oz they used to clean out farm dams with a drag kinda like ya box blades one tractor on each end (like a cross cut saw) big tractor to pull load out of dam and smaller to pull drag back maybe thats another way to do it ,big digger maybe other way too ok it will silt the water up but that will clear only thing is if there is any fish in pond the silt blocks the gills and well "it's eazy fishing with a 30 tonne digger"is all i'll say about what happens
catch ya
JD Kid

 

[JohnS]

Hi Patrick, As only a pond dreamer, I envy your problem with your SEVERAL ponds. My dad and I considered a similar approuch a few years ago, at our camp. About 1/3 of the water front is nice sandy/gravel bottom, the other 2/3 is muck bottom. In our case, there were not many options on where pump the water/silt to. After we did the rough volume calculations, we realized the futility. Never tried it to see how well it would have pumped. We also found out that we would have broke numerous DEC rules in the process.

I have seen an earthern dam pond that was fully silted fixed by digging a trench on the outide edge and breaching the dam in the corner. It was allowed to dry, and bulldozed out, and dam repaired. Partialy silted pond would require draining. And depending on the water supply if it could actually dry out enough to get equipment in there.
If these are dugout ponds, there might not be many options.

Its probably worth getting a local experienced pond contractor out to take a look. Get his recommendations and suggestions. I had one out to my place to help scope possible pond locations. Even though I had read a few books on pond building, his local exp and knowledge was invaluable. This guy has done all my friends hatchery and fee-fishing ponds, and just about all larger ponds (2+ acres) in our area.

One of my possible sites will require a smaller silting pond ahead of the main pond. Additional cost, but it will also serve as a fathead minnow breading pond. Good bait supply and will keep the bass below nice n big!

I will be interested in how well the pumping works out.


PS: Now if I can just get that contractor back to get those test holes done!

Dreaming of ponds full of bass and cats.....
JohnS

 

[JohnS]

Re: Opps, just figured out how to smile here!

/w3tcompact/icons/smile.gif

JohnS

 

[JATO_RaT]

Patrick, ahh yes, a dredge is a fantastic way to move material. Your talking to a guy who lives a few miles from where James Marshall discovered gold that eventually led to the 1949 gold rush. Here in Northern California, (not to be confused with the freaky Southern California, except maybe for the Bay area around San Francisco), gold dredges have been used for quite some time. I used to use a 6" dredge on the North Fork of the Yuba River. It had a 16HP pump that sat on floats which also contained an air pump for divers (hooka). The pump powered water through a 2 1/2" hose down to the venturi that ran the 6" dredging hose. You can still get all the equipment out here in the local dive shops. I'll have to look some up on the web to see what they carry.

I have a tremendous pond silting problem. Trouble is, its fed by a year round stream. Someone above me had a dam that broke which sent the bulk of what is now my problem. I think I can divert the stream, drain the pond and excavate. I have built a sediment pond at the mouth where hopefully the bulk of the sediment will lodge and could be removed more easily. I'm still working on the strategy of this pond that is sitting in the valley of 2 hills with a small earth dam on the one end. Let me know if you need some info from a local shop on dredges, perhaps I can dig it up. I'm sure they have pump/hp info as well as material volumes you can move with a given size. Rat...

 

[ERNIEB]

Here in Texas ponds are usually called tanks. I know of a few that have been cleaned out, none were done by pump or dredge. One that I got involved with, a guy just drove a large backhoe down into the thing when the water was low. He called me up to see if I could haul off the stuff that he had taken out. He had tried to haul it off himself, but there were water lines he had broke, not enough room for his backhoe, and so on. I was busy at the time, but the guy said it had been six months, and the owner was bugging him to get the stuff out of there. So, I swung by to take a look at it. It looked like about 40 yds of dirt, fairly dried out. I figured me and the TC29, along with my 6 yd dump would make short work of it. I should have known better, and looked closer. I called the guy back, and gave him a price. He said go for it.
When I pulled out my first bucketfull, I saw I had made a mistake. Only the top 4 inches was dry, underneath was a wet sticky black goop, that I can only say was like trying to load and haul axle grease. I got it done, but it took about twice as long as I thought.

Ernie