Duck pond - bottom drain?

[lidiam]

Hello

I'm new to this forum and am a bit overwhelmed with all the information here. I'm building a two pond system: a small above ground pond, roughly 3' x 5' and in the ground pond, yet to be dug out, roughly 10' x 5'. I have ducks and the larger pond is mainly for their use. I've had an above ground hard shell pond and in the ground kiddie pool for several years, till the hard shell pond developed a crack in the bottom a few months back. I decided to replace it with something more permanent. The upper, hard shell pond was holding WH as filtration, and mosquito fish (although they pretty much all migrated to the duckie pool).

I'm attaching photos of the above ground pond construction (cinder blocks with steel stakes and rebar). I filled it with some soil to make it two level and added sand. I have underlayment and EPDM liner ready, however, now I'm considering two things:

1. Should I make a hole in the bottom of the upper pond for draining? I did not consider this till finding some posts/photos in this forum with bottom drains. I had an issue with lots of black muck accumulating in the upper hard shell pond. I added a felt filter and a second pump that was taking water from the upper pond to the yet higher felt filter, but, much to my surprise, that didn't help much. Perhaps I need to drain the upper pond on regular basis to avoid this problem? That would be a hassle. I'm hoping that perhaps I can add some small water bugs that would eat the muck.

2. What is the best way to top off the lip of the pond? I want to use a somewhat flat stone to have water fall off it and over the rocks to the lower pond. I'm thinking of adding a layer of about 3" of mortar everywhere around, apart from the "waterfall" section. I would then put the underlayement and liner over the lip of the pond. The "waterfall" rock would also go over the liner, although I'm not sure how it would be attached to it. I've seen posts that mortar won't hold it. Would I need to glue it in place? Any other options? I presume liner has to go over the lip of the waterfall so that water does not seep in. Am I correct here?

I found some posts suggesting embedding pieces of wood in the mortar at the top, so that liner can be nailed to them. I like the idea. I presume there is no issue with this upper layer of mortar holding water (without any reinforcement) - there would probably be about an inch of water held by the mortar wall (that's how thick the "waterfall" stone is). Is there something else I should use instead?

Thanks for any pointers.

Lidia

 

[lidiam]

Forgot to mention, I'm California - no worry about freezing.

Lidia

 

[Lisak1]

Hmmm... I guess I'm unclear about your construction questions but someone who has more experience with that will hopefully pop in here. I think you may be asking though if mortar holds water - the answer is no. Water will seep through mortar.

And you may be asking about being able to back flush your pond. It sounds like you are using this almost as a planter filter. How deep with the water be in this portion? If the muck is from the ducks I think you will always have this problem. If the muck is from organic material breaking down in the pond, then more frequently removing dead leaves and plants would probably reduce the muck.

Or maybe you're asking about a bottom drain in the duck portion of the pond? Will you have a filtration system on the pond? Quite honestly ducks in a pond is a whole other kind of animal than a fish pond. Ducks are notoriously dirty and will produce a lot of waste in a pond - far more than fish would. I think you may need to drain and clean a pond like this on a regular basis. But again, no actual experience... just thinking out loud!

 

[j.w]

@lidiam
I think for a duck pond one would need a much larger pond and a very good filter to somehow keep it clean and a bottom drain might help. Some here do allow ducks in their ponds so hopefully they will speak up to help you.

 

[lidiam]

Hmmm... I guess I'm unclear about your construction questions but someone who has more experience with that will hopefully pop in here. I think you may be asking though if mortar holds water - the answer is no. Water will seep through mortar.

And you may be asking about being able to back flush your pond. It sounds like you are using this almost as a planter filter. How deep with the water be in this portion? If the muck is from the ducks I think you will always have this problem. If the muck is from organic material breaking down in the pond, then more frequently removing dead leaves and plants would probably reduce the muck.

Or maybe you're asking about a bottom drain in the duck portion of the pond? Will you have a filtration system on the pond? Quite honestly ducks in a pond is a whole other kind of animal than a fish pond. Ducks are notoriously dirty and will produce a lot of waste in a pond - far more than fish would. I think you may need to drain and clean a pond like this on a regular basis. But again, no actual experience... just thinking out loud!

Thank you Lisak1 for the pointers. Yes, ducks create enormous amounts of dirt in the water. I don't let them eat in the pond, that helps somewhat.

Regarding mortar - I don't expect it to be waterproof. There will be pond liner against and over the mortar. I'm just wondering if it's ok structurally.

I was considering flush plug in the upper pond, where water hyacinth is going to live - about 3 feet deep in the deepest part. That's where the muck accumulation was happening before. A year ago or so, I added a barrel with felt as a filter but that didn't help much. Basically I had a two pump system: one pump from lower pond to upper pond, then second from upper pond to a half barrel up high with felt (NOT holding water) and then water was flowing back to the lower pond. With adding some pond zyme, pretty much nothing was accumulating in the lower pond that ducks use, but upper pond would fill with black, stinky muck within 6 months. I'm hoping to find some water bugs/creatures that would slow down the muck accumulation. I found 'sawbug' (asellus aquaticus) in my search online. No idea if it would survive, make a difference, not where to get it from. Perhaps there are other, better ones.

Lidia

 

[Lisak1]

I think you're going to have to accept that this isn't a natural situation and needs to be maintained. Theres no bug or creature that I know of that will keep the muck at bay. In nature, you'd have interaction at the bottom of the pond with the sub-soil. In a liner pond, you don't have that. So you may just have to keep cleaning it out. I'm guessing the muck accumulates in the top pond because the bottom stays stirred up by duck activity. It can settle in the top pond, so it does. A more sophisticated filtering system might help - I'm not sure felt pads are the way to go, as they would just clog up quickly I would assume. Most filters of that type would have a variety of filtering material to catch everything from the largest to the smallest particles.