You know you are a total nerd when the highlight of your day is a brief rainstorm that fills your rain barrel half way. With the new (actually 20+ years old and re-used) gutter all the rain is now directed to the barrel and our five minutes of heavy rain just now filled it to half. Sweet. I can't wait to get the others and hook them up into a proper series. I'd like to put in 10 but I may only be able to fit 8 or 9 which would still be a nice bit of water to have around. Given that this barrel would have filled in just 10 minutes I'd estimate that 8 barrels will easily fill in less than two hours with a fairly hard rain, much less if the rain were as heavy as what we just had. Maybe I need 20 barrels?
My expectations of a future shaped by climate change and peak energy is that we must become very efficient at harvesting and using/conserving fresh water. It seems to me that we can expect increasingly erratic weather with periods of extreme drought and wet far beyond what we've seen in the past. Combine that with the myriad issues related to agriculture and peak energy and you have lots of trouble in regards to a steady food supply.
If I can harvest and store 1650 gallons of water for use during drought then I will... guess I need 30 barrels!