New Member: Constructing a Natural Swimming Pond - 09/08/14 01:03 AM
Hi!
I am new to the forums here. I've been doing a ton of research because my hubby and I are renovating a farm pond to create a natural swimming pond. While a search here yielded nothing on this topic, the basic goal of a natural swimming pond is clear water via a healthy balanced ecology, so I figure there's lots that you all can tell us!
We bought our farm in 2011. It had been abandoned for thirty years and has two large ponds (both spring fed) as well as three spring boxes (one of which is our water supply for the house). In 2012, we had the upper pond breached and dredged with heavy machinery and then, in 2013, we bought sheep so we put a fence around it. (Sheep will drown in ponds with clay sides that are steeply sloping, and besides, we really wanted to make the upper pond into a family swimming hole, since we have such an abundance of water, and the lower one into a fishing pond.)
We were advised to put ONE grass carp in each pond, to help keep pond weeds down. We did that. Then, in 2013, we decided (before fencing both ponds) to dredge the lower pond as well. It was February, and our excavator found the large grass carp in the mud and put it into the upper pond, so it would live. Our understanding was that both fish were sterile.
But, of course, they weren't. As a matter of fact, it seems that we have two kinds of fish in this pond: some kind of orange, koi-like kind and some silvery ones: more like grass carp. Whatever they are, they do eat all the weeds but they also churn up the mud constantly. So, last summer and this summer, there have been baby fish in our upper (erstwhile swimming?) pond. The water snakes came in after the fish, and the multiple fish also constantly stirred up the bottom so the thing looked like muddy green yuck this summer. Added to that, two years of sedimentation without much clean up or care on our parts (we've been busy with other things) and stagnant water have resulted in a place that is none too inviting for swimming!
We kicked around the idea of not fighting nature, but just making it a real fishing pond, and building a modern, chlorine swimming pool, but the costs are way beyond our reach. I did some 'net surfing and would up researching natural swimming ponds--very common in Europe, but little known here.
This article is a good start in case you wonder what I'm jabbering about here: Mother Earth News: DIY Natural Swimming Pool .
The idea is that you create an internal barrier in the pond, which reaches vertically from the bottom of the pond to within 2" of the surface, using something rigid like stone or wood and a liner (if you aren't lucky enough--as we are--to have a clay-bottomed, established pond that is spring fed and therefore never lacks water at a level set by the overflow). This central zone for swimming is connected to (and usually rimmed by) a "regeneration" zone, reserved for plants, which because they are planted on crushed rocks, naturally clean the water by removing nutrients and thus starving algae into submission. You also rely on aeration, and some swimming ponds have circulation pumps, UV sterilizers, and skimmers. (In fact, purists among the NSP advocates get pretty shirty with these later additions, saying that they are no longer natural, but that's outside the scope of this post. :D)
The pond's internal barrier both defines the swimming area and keeps the plants in check, since you grade the gravel in the plant area from the shore downward on a slope to meet the barrier at a depth of about 18"-2'. The gravel is supposed to provide lots of surface area for aerobic bacteria. If you aren't going to augment circulation with an electric pump, then you need a 50-50 surface ratio between your swimming and regeneration zones; those with more technology can get along with a 65-35 ratio. Our pond will have the 50-50 ratio, since we don't have electricity near the pond.
However, we have decided to purchase a windmill-driven aeration system from Koenders. It will have two air stones, which we'll place at extreme ends of the elliptical swimming zone of our pond. Our plan is that the plants and the aeration (along with possibly some muck-eating pellets added this winter to help the aerobic bacteria clean up the 6" of muck that's accumulated in the past two years) will result in a clean, fish-free swimmin' hole next summer.
Note that I said "fish free." We have had a long, dry summer, and it seemed like it was "now or never" for this project, so we've been draining the pond for a week using siphons. Our pond measures 80' X 50'. We're down to about 18" of water, and this week it's "catch all the little fishies."
Which leads me to my first question of this thread.
One disagreement that my hubby and I have is whether or not it's reasonable to think that we can catch all the fish? (Full disclosure: hubby thinks that we can drain all the way down to the muck, and leave them high and dry, and I think that our siphon will give out before then, and want to put enough table salt into the few inches of water that I'm sure will remain so that all fish that we can't catch--and any eggs--die from too much salinity.) Sad for the fish... but I can't help it. We'd love to hear what others think of our chances of catching all the fish/fish eggs, and how you'd go about it if you were us. (Would minnow traps work, for instance?) I'd love to be humane about this!
The second opening question is this: we have some piping through out dam: it's a 2" PVC that we had put there when we breached/redid the pond, and (miraculously) it doesn't leak. My hubby wants to plumb this into a sump of sorts at the lowest part of the pond by buying a plastic tub (large), sinking it to the lowest spot in the pond, running shallow ditches to it, and bulkheading it and then plumbing it such that we can, next time, drain the pond faster than the current method of having three 3/4" hose siphons running. He would plan to cover the tub with 1/4" mesh to keep it from getting clogged, and plumb PVC (glued) on the other side of the dam down our hill so that it's outlet is below the pond bottom, with a ball valve, so that he would have a simple siphon. Anyone tried anything like this with a pond as big as ours? Mistakes made and lessons learned? Cautions?
I have many pictures to share: this is a fun project and I'm doing a photo essay on it. I'll put up a few here on my next post.
I am new to the forums here. I've been doing a ton of research because my hubby and I are renovating a farm pond to create a natural swimming pond. While a search here yielded nothing on this topic, the basic goal of a natural swimming pond is clear water via a healthy balanced ecology, so I figure there's lots that you all can tell us!
We bought our farm in 2011. It had been abandoned for thirty years and has two large ponds (both spring fed) as well as three spring boxes (one of which is our water supply for the house). In 2012, we had the upper pond breached and dredged with heavy machinery and then, in 2013, we bought sheep so we put a fence around it. (Sheep will drown in ponds with clay sides that are steeply sloping, and besides, we really wanted to make the upper pond into a family swimming hole, since we have such an abundance of water, and the lower one into a fishing pond.)
We were advised to put ONE grass carp in each pond, to help keep pond weeds down. We did that. Then, in 2013, we decided (before fencing both ponds) to dredge the lower pond as well. It was February, and our excavator found the large grass carp in the mud and put it into the upper pond, so it would live. Our understanding was that both fish were sterile.
But, of course, they weren't. As a matter of fact, it seems that we have two kinds of fish in this pond: some kind of orange, koi-like kind and some silvery ones: more like grass carp. Whatever they are, they do eat all the weeds but they also churn up the mud constantly. So, last summer and this summer, there have been baby fish in our upper (erstwhile swimming?) pond. The water snakes came in after the fish, and the multiple fish also constantly stirred up the bottom so the thing looked like muddy green yuck this summer. Added to that, two years of sedimentation without much clean up or care on our parts (we've been busy with other things) and stagnant water have resulted in a place that is none too inviting for swimming!
We kicked around the idea of not fighting nature, but just making it a real fishing pond, and building a modern, chlorine swimming pool, but the costs are way beyond our reach. I did some 'net surfing and would up researching natural swimming ponds--very common in Europe, but little known here.
This article is a good start in case you wonder what I'm jabbering about here: Mother Earth News: DIY Natural Swimming Pool .
The idea is that you create an internal barrier in the pond, which reaches vertically from the bottom of the pond to within 2" of the surface, using something rigid like stone or wood and a liner (if you aren't lucky enough--as we are--to have a clay-bottomed, established pond that is spring fed and therefore never lacks water at a level set by the overflow). This central zone for swimming is connected to (and usually rimmed by) a "regeneration" zone, reserved for plants, which because they are planted on crushed rocks, naturally clean the water by removing nutrients and thus starving algae into submission. You also rely on aeration, and some swimming ponds have circulation pumps, UV sterilizers, and skimmers. (In fact, purists among the NSP advocates get pretty shirty with these later additions, saying that they are no longer natural, but that's outside the scope of this post. :D)
The pond's internal barrier both defines the swimming area and keeps the plants in check, since you grade the gravel in the plant area from the shore downward on a slope to meet the barrier at a depth of about 18"-2'. The gravel is supposed to provide lots of surface area for aerobic bacteria. If you aren't going to augment circulation with an electric pump, then you need a 50-50 surface ratio between your swimming and regeneration zones; those with more technology can get along with a 65-35 ratio. Our pond will have the 50-50 ratio, since we don't have electricity near the pond.
However, we have decided to purchase a windmill-driven aeration system from Koenders. It will have two air stones, which we'll place at extreme ends of the elliptical swimming zone of our pond. Our plan is that the plants and the aeration (along with possibly some muck-eating pellets added this winter to help the aerobic bacteria clean up the 6" of muck that's accumulated in the past two years) will result in a clean, fish-free swimmin' hole next summer.
Note that I said "fish free." We have had a long, dry summer, and it seemed like it was "now or never" for this project, so we've been draining the pond for a week using siphons. Our pond measures 80' X 50'. We're down to about 18" of water, and this week it's "catch all the little fishies."
Which leads me to my first question of this thread.
One disagreement that my hubby and I have is whether or not it's reasonable to think that we can catch all the fish? (Full disclosure: hubby thinks that we can drain all the way down to the muck, and leave them high and dry, and I think that our siphon will give out before then, and want to put enough table salt into the few inches of water that I'm sure will remain so that all fish that we can't catch--and any eggs--die from too much salinity.) Sad for the fish... but I can't help it. We'd love to hear what others think of our chances of catching all the fish/fish eggs, and how you'd go about it if you were us. (Would minnow traps work, for instance?) I'd love to be humane about this!
The second opening question is this: we have some piping through out dam: it's a 2" PVC that we had put there when we breached/redid the pond, and (miraculously) it doesn't leak. My hubby wants to plumb this into a sump of sorts at the lowest part of the pond by buying a plastic tub (large), sinking it to the lowest spot in the pond, running shallow ditches to it, and bulkheading it and then plumbing it such that we can, next time, drain the pond faster than the current method of having three 3/4" hose siphons running. He would plan to cover the tub with 1/4" mesh to keep it from getting clogged, and plumb PVC (glued) on the other side of the dam down our hill so that it's outlet is below the pond bottom, with a ball valve, so that he would have a simple siphon. Anyone tried anything like this with a pond as big as ours? Mistakes made and lessons learned? Cautions?
I have many pictures to share: this is a fun project and I'm doing a photo essay on it. I'll put up a few here on my next post.