water saving thoughts

so it is clear that it is not going to rain enough here to get the water table back up,
so I have been thinking of other ways to deal with water savings,
I remembered about that sealed green house out in new mexico,
they called it Biosphere 2,
http://en.wikipedia.org/wiki/Biosphere_2
and they only had to add water once,
I like that idea,
but on closer reading, they spent 3 times the energy that fell into the structure from the sun just on cooling,
and that is lots of energy, so maybe I could use heat pipes to get rid of the extra heat energy,
but it sounds expensive
even if I can't make my own version, there are all kinds of fun lessons they learned with the project,
like Calcium carbonate forming and taking the oxygen and carbon out of the air

maybe making the water holding capacity of the soil and flat stones or cardboard to keep the sun from evaporating the water is going to be enough,

big farmers use drip systems, will have to look into them next,
and look at heat pipes to see if they will be possible to setup for greenhouse cooling.