Moving to silted ponds... help!!!

[Tula]

Gorgeous piece of property and glad to see you posting again

 

[johan]

My wife and I maintained a very remote property that had 6 ponds, the largest was 13 acres. There was a ditch feeding it, about 1/4 mile long and it was not accessible with any large equipment. Along the way was a pond that silted up badly, one we used for rearing fingerling trout, before release into the ponds. About 50 feet away, but only a foot or less higher was a large flat grassy area. We used a 4" gold dredge to suck out the silt. It did move a lot of water though. The dredge had no problem moving large quantities of silt and plants with a small lift, to distances of over 50'. Running back into the hole, after 50 feet of grass filter, pretty much settled the silt out of the water.

If you dig out in one area at first, till you run low on water, then let it fill and do it again, in a few hours of off and on work, you'll have a large reservoir of water to work from.

A settling pond ahead of the inlet would make things simpler, someplace where the silt could be easily cleaned out as needed.

That's already a beautiful spot, you're very lucky to have it!

Steve

Ahhhhh, brilliant, thanks Steve, just the sort of experience/advice I'm after... looks like what I have in mind might be roughly doable by myself and some bought gear, rather than hiring externals! Maybe I should designate that top pond just as a settling pond for the main one, although it does seem churlish to waste an entire pond. But hey ho, as needs...

Yes, I keep pinching myself, I'm very lucky to live where I do, it's an absurdly pretty spot. We have nightingales in the garden, badgers and foxes at night and usually there are owls hooting away every winter (babies calling in the nest). Believe it or not the county just south of London whee I am - Surrey - is actually the most forested county in the UK, and we live in a tiny village in the middle of it.

Like many villages here in the Surrey Hills, it a grand old Victorian mansion up on the hill, and the house we've bought was once one of the four lodges for that mansion (lodges are typically the gate house where the servant lives). Bottom line these ponds were formal ponds lining the grand old driveway a century ago. For sure, there's lots of work to do on this place, it'll take a while and it'll cost us a pretty penny, but it's our 'forever' home so lots of time to make and do lovely things!

 

[johan]

Gorgeous piece of property and glad to see you posting again

Aww that's nice, thank you. It's a nice community this - I just got very distracted by my other passion and my pond was doing fine at the old house. Must take some nostalgia photos of it before I go!

 

[Jhn]

Another approach is to put in stepped settling pools in the streams between your ponds, especially the upstream portion leading from the neighbors properties. Then you would just need to stay on top of pumping the smaller pools out. (kind of what Stephen T. mentioned)
This is a typical stream restoration technique, where streams have become severely restricted from silt. Downside is it usually takes machinery to do this on large scales, as you are changing around the way the stream flows.

Also, if you use an agitator or trash pump to suck the silt out of the ponds, install a reinforced silt fence on the downhill side of the pump outlet. The silt fence will catch the sediment and let the water pass through, helping to keep the sediment from ending up back in the pond.

Sounds like fun restoring the ponds.

 

[johan]

Another approach is to put in stepped settling pools in the streams between your ponds, especially the upstream portion leading from the neighbors properties. Then you would just need to stay on top of pumping the smaller pools out. (kind of what Stephen T. mentioned)
This is a typical stream restoration technique, where streams have become severely restricted from silt. Downside is it usually takes machinery to do this on large scales, as you are changing around the way the stream flows.

Also, if you use an agitator or trash pump to suck the silt out of the ponds, install a reinforced silt fence on the downhill side of the pump outlet. The silt fence will catch the sediment and let the water pass through, helping to keep the sediment from ending up back in the pond.

Sounds like fun restoring the ponds.

More useful advice, thanks!

Yes, should be fun. It'll be nice to make it all beautiful

 

[MitchM]

Sounds like you're getting some good advice.
My concern about placing the silt in the forested area is that if it is placed all in one spot, it could suffocate some of the surrounding tree roots.
What a lovely area.

 

[johan]

Sounds like you're getting some good advice.
My concern about placing the silt in the forested area is that if it is placed all in one spot, it could suffocate some of the surrounding tree roots.
What a lovely area.

Yes, I don't think putting it all in one spot would be great. Thankfully I have a couple of acres top spread it over

 

[Eric Blair]

Ahhhhhhhhh - good maths, thanks. Yes you've exposed an obvious problem! That said, I suspect I'll need to overengineer the pump because I want to be able to pump the silt out onto our land, some distance away from the stream. Can't have the stuff going back into the water at the first sign of rain



Combined

I hope this is not a stupid point but could the silt be used by a garden centre or something? It might be nutrient rich (I don't) so maybe someone would want to take it away for you.

 

[johan]

Does anyone have any experience with a small lake and using an aquasweep to circulate water so that silt is carried off downstream?

 

[Meyer Jordan]

Does anyone have any experience with a small lake and using an aquasweep to circulate water so that silt is carried off downstream?

Why would you want that to occur. The core of an earthen-bottom body of water is the Benthic layer, which is the accumulation of silt and organic matter at the bottom of pond. It is the home of many aquatic organisms that will reside in no other part of a pond and is part of the base of the aquatic food chain.

 

[johan]

I maybe have too much of a Benthic layer - 130 years worth of silt buildup has turned my half a mile of stream into half a mile of silt with some water meandering over the top...

 

[Meyer Jordan]

Sorry, I forgot that your situation is somewhat unique. In fact I believe that I originally recommended dredging.
I am not familiar with this aquasweep device, but I have had experience with similar devices and unless these devices can be kept in constant movement across the bottom of a pond they will quite quickly excavate a hole in the bottom of the pond. If set to close to the pond edge and cause erosion issues.

The above photo is from a project that I worked on several years ago. The customer had let someone place a device in the pond that stirred up the bottom sediment which was then removed through the use of an overflow. The device was stationary and had excavated a 10 foot deep x 10-12 foot wide hole in an area of the pond that otherwise averaged 3 feet in depth. This resulted in major erosion along the entire pond perimeter but most dangerously on the North side where electrical and irrigation conduit was exposed.
If a pond is to be dredged properly.it must be drained first. Only then can the amount of sediment removal be controlled and removed in an even amount across the floor of the pond. In addition, any areas of possible erosion can be addressed and stabilized.

 

[johan]

Eeek, so it does work but maybe a little too well. My plan is not to let it stay in the water permanently but to don waterproof waders and to manage sessions to clear up the silt. There's no way I can clear the lakes because there's a living stream feeding them and exiting from them. Hmmmmm, and ... thanks

 

[Meyer Jordan]

My plan is not to let it stay in the water permanently but to don waterproof waders and to manage sessions to clear up the silt.

Given the size of these ponds, what you are proposing above may turn out to be an exercise in futility. Without a fairly large flow traversing the pond, most of the stirred up silt and debris will just resettle elsewhere on the pond's bottom before reaching any overflow. And this would only upset the biological ballance established over the years with no benefit derived.

 

[Usman]

https://www.youtube.com/watch?v=Q6qkG2UOxyI


https://www.youtube.com/watch?v=-LZGj9GfQzE