Sump tank design and pump?

[GaryMoz]

I'm really please with my new pond it's a hybrid pond using both bottom drains and a bog filter. The only problem I have is the amount of water I get through, I'm using a drum filter and it and with evaporation I must be using 500 up to 1000 ltrs a day and with UK water costs it mounts up. I'm already using rain water tank from 30m2 of roof but that's no where near enough ( that's about 21000 ltrs a year, if the pond uses 500ltrs a day that's 182000 ltrs a year (blimey that's more than I thought). At the moment if the water tank fall below a certain level, it automatically adds a some tap water.

So I'm thinking of sinking a a hole and trying use water from the water table. When will built the pond 1500mm deep, the bottom 300mm filled with water. So I'm thinking of just digging a deep hole, say 2000mm deep, line it with inspection chamber risers with holes cut in, and drop something like an on demand pump like this borehole pump, then use this to feed the rainwater tank, which feeds the pond.

The borehole pump could go directly to the pond, but I'm worried if the water table lowers and dries up (note: water is strangely high where I live, I think it is because a spring water is being trapped on a clay layer). so no water to top up pond.

I should mention the pond does need it's water level automatically maintained.

Cost is another issue, it all mounts up.

Anyone with experience of doing this and the most cost effective way?

 

[GBBUDD]

As you know i have a cistern 3000 gallons and only vocational do i need to help out luke now I don't think we have had any rain in two months now.
But your idea of a well is a good one but I question if shallow well we be a problem. With introducing organic or polution. But you know your area better than I do . Here in the states there's no undisturbed land left. And God only knows what was where a hundred years ago . I know to you 100 is nothing but you get the point.

Nothing ventured nothing gained.

I know you travel a lot and are worried about how much the well may deliver before it runs dry . So why not leave your tap water float. Just have it activated a a point when the water drops to where you know the well has failed.