Quick Fire Guide to Cascades

Submitted by mrravello on Mon, 09/07/2007 - 6:47pm.

I need to re-line an old garden pond(3mx2.5m) and replace the waterfall. Your article is great and as I have lots of stone from the old waterfall I intend to follow your design and plan. I would just like to ask 2 questions:
The pond will not have fish in it and there is an exisiting header pond (1.5m x 0.5m) which will feed the 3 "cascade" ponds I am building. So, does the flow rate mentioned in your article apply "Try not to circulate more than the total volume of the pond every hour. This will damage the eco-system. Once every 2 hours is more desirable". I think my pump would take 12 hours to move the pond through the cascade. Is that OK?
Secondly, is ther any point in taking out the old liner? I had intented to lay the proper underlay over the exisiting liner and then the new (Butyl)one on top.
If you have the time to answer that would be very much appreciated.

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Re: the questions relating to the 'Quick fire guide to cascades'

Submitted by Peter May on Mon, 09/07/2007 - 7:56pm.

The flow rate mentioned is really a maximum to avoid. Anything less is ok.
A lot of people incorporate a biological filter at the top of a waterfall - which incidentally I dont think is a very good idea, but that's another topic - and since many bio-filter manufacturers specify that you turn over half the volume of the pool every hour then you have this ideal that seems to be set up in people's minds. If fact, if the stream/waterfall is not too turbulent there is a certain amount of biological filtration/breakdown of organic matter that goes on.

With regard to the old liner - if it is clean and pebble free, there is no reason why that cannot work as an underlay to the new liner, especially if it has its own underlay beneath that.

By the way, even if your pond is 1metre deep, it is only going to be a maximum of 7500litres(1500gallons). That means if you were aiming to turn over the pond water every 2hours, you would only need a 4000litre per hour pump (as long as the waterfall was not too high. That's not a lot more powerful than the pump I used in the 'Quick Fire Guide'.

Another 'by the way'- it would be great if you send in a picture of it when you've finished it!


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Quick fire guide to cascades

Submitted by Peter May on Thu, 18/09/2008 - 8:25am.

Sorry about my late reply mrravello. Your posting slipped my net somehow.
The turn over of water by a cascade relative to the volume of water in the pond is irrelevant unless it is more than the total volume of the pond - that is what I should have said. You can have a cascade or water fall just as a trickle. The only thing that dictates the flow is how it looks - the aesthetics.
If there was a filter system incorporated in with the waterfall then whatever the filter system requires would the dictate the parameter of the flow. With many modern biological filter systems, this is usually the total volume of the pond every two hours. I do know a designer of some very good and special filter syastems that recommends only filtering the total volume of the pond every 12 hours.

And yes it would be fine to put the new liner on top of the old one especially with an underlay.

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