# Cistern to use seasonal creek to irrigate lawn



## Bondo (Dec 8, 2007)

> 1] If I put a cisten in below ground level how do I prevent the cistern from 'popping up' during periods of high water level?


Ayuh,... I'll admit,... I've never Tried what you're proposing,....
But,...
I'd Think that you'd keep the cistern absolutely Full,.. Whenever there's *Any* flow from the creek,.. 
And when it's Full, it shouldn't try to lift up.....

I'd also Think that if you Bottom fill the tank, You'd have what's known around here as a "Shore Well".... Not a cistern at all....
And I can tell you that when the water goes down, or in your case the creek stops flowing,....
Shore Wells usually go Dry.....
But, if the water table is as High as you say,... It just might work...

Btw,....
No Matter What you do,... Tree Roots will follow the Water.....


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## Jeff in Poway (Jul 28, 2008)

*Probably best to top fill....*

Thanks for your input Bondo - anyone else care to share experience or knowhow here?

I think I'll buy a 850 gallon tank, but limit usage to 500 gallons (i.e. limitsprinkler use @ 18GPM for 25 minutes and set the float switch height in the tank accordingly). I'll need to make bouyancy force calculations to see if the residual weight will off set the BF, but i need to factor in the weight of gravel or dirt on top as well, and could drop the tank low enough to put 1-2 fett of dirt on top.


Comments anyone?


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