Pond overflow

[Durris Dave]

we are in process of building a new steading and need a 50000 litre " fire fighting " pond . We have an old dam which fed a mill back in the day which I'm going to reinstate and wandered if anyone had any good ideas for overflow/ drainage the dam is fed with a mill laid which runs all year so has to be reliable and if it blocks my new steading is flooded !!

 

[Derky]

Now then, hope all is good with you ?
Job to picture but any ponds we have done which need an overflow we always put in a 12 pipe just below ground surface running to a ditch or brook, so it sets the level. We did one once with a v bucket and put paving slabs in the bottom. The client wanted it and once it greened up looked good.

 

[Steevo]

Make sure the pipe you put in is big enough. Not so much for flow of water, but to stop any leaves etc. floating on the top from blocking the entrance of it.

 

[Landy Nick]

We put in two six inch plastic waste pipes in, side by side on our 3 acre lake as an overflow. In 25 years plus they have never blocked. The pipes are about 12ft long. So if they ever did block, then it's only a short run to clear. If we wanted to raise the water. Then we just push on two 90 degree bends facing upwards to act as standpipes.

 

[renewablejohn]

Our dam gave way in last winters storms so just getting round to repairing it. We have two 4 inch pipes set under the dam draining down the original stream. 90 degree elbows on each into the pond then a standpipe on each topped with a stainless steel washing machine drum. Each pipe staggered at different heights so normally 1 pipe running all the time and when the pond rises 1 foot the other pipe starts running. On top of dam is 12 x 6 inch pipes and spillway for the occasional flash flood.

 

[Andrew1983]

Did/do u need to get permission to reinstate a pond? Iv a similar mill pond above steading that's been left to fill in with silt, its just got a narrow channel running through it.

 

[renewablejohn]

Did/do u need to get permission to reinstate a pond? Iv a similar mill pond above steading that's been left to fill in with silt, its just got a narrow channel running through it.

Depends on the size a lot of old mill ponds will now be caught under the reservoir act when I last looked it had been reduced down to 10,000 m3 which is not very big.
If its below 10,000 m3 I would just crack on and reinstate it but do your research first as many mill ponds have a plug to drain the pond.

 

[glow worm]

we are in process of building a new steading and need a 50000 litre " fire fighting " pond . We have an old dam which fed a mill back in the day which I'm going to reinstate and wandered if anyone had any good ideas for overflow/ drainage the dam is fed with a mill laid which runs all year so has to be reliable and if it blocks my new steading is flooded !!

Hard to picture layout but on our pond, the overflow is only a few yards from the inlet. A ditch in, a ditch out. No pipes. A solid dam wall the other end with no outlet. Works a treat. Except for very dry times, there is a steady flow of water year round. Has never blocked with leaves ... yet!!

 

[chaffcutter]

Have you got enough drop height on the overflow to be able to fit a turbine for cheap electricity? Just a thought, saw one on a mill leat years ago in s. Wales

 

[Durris Dave]

Depends on the size a lot of old mill ponds will now be caught under the reservoir act when I last looked it had been reduced down to 10,000 m3 which is not very big.
If its below 10,000 m3 I would just crack on and reinstate it but do your research first as many mill ponds have a plug to drain the pond.

My mill pond is 9,999 m3 phew !!

 

[Durris Dave]

Hard to picture layout but on our pond, the overflow is only a few yards from the inlet. A ditch in, a ditch out. No pipes. A solid dam wall the other end with no outlet. Works a treat. Except for very dry times, there is a steady flow of water year round. Has never blocked with leaves ... yet!!

Sounds a good idea . With the outlet so close to the inlet do you not get any bother with the pond going stagnant at the other end ?

 

[Durris Dave]

Now then, hope all is good with you ?
Job to picture but any ponds we have done which need an overflow we always put in a 12 pipe just below ground surface running to a ditch or brook, so it sets the level. We did one once with a v bucket and put paving slabs in the bottom. The client wanted it and once it greened up looked good.

Good thanks how's you ? Digger going great. Started a bit of site clearance with it but it will be steady digging for the next few weeks! Yes was thinking something along those lines . As its a mill pond it has a 12" mill laid feeding water all the time so will need a reliable outlet. The current outlet runs under the old steading and will have to be done away with due to changing levels in the new build.

 

[glow worm]

Sounds a good idea . With the outlet so close to the inlet do you not get any bother with the pond going stagnant at the other end ?

Had wondered if we would but all seems ok. Its a fairly open site and has a fair swell on it a lot of the time. Certainty saves a lot of faffing around with pipes and slucies!

 

[renewablejohn]

Anyone know what thickness of puddled clay is required to achieve a waterproof membrane.