With the drought and all of the talk about conservation, rain barrels hooked up to the down spouts are getting a lot of attention. I had an idea yesterday and would like some opinions. I was imagining a huge tank located underground that was fed by all of the down spouts. Sporadic rainfall could be collected and used for irrigation at a later time. It could also be set up to divert if full. There's a lot of unanswered questions, so I pose them to you.