Aha,
I finally re-found this thread. I recalled seeing the pictures before but couldn't recall the details.
Since I have a great project, raising all types of veggies in a 4'x50-80' raised bed, I need to set up a water collection system. I figure I need about 150 gallons of water to cover 240 sq. ft. of space and provide what equals roughly an inch of rain. Six barrels would give me enough for two weeks, three weeks if we get an inch of rain to replenish the barrels.
But questions about your design: did you find that the hose that runs from the highest barrel to the next one was large enough to handle a short, heavy downpour. I'm hoping, if I can find some company to add gutters to the building or something similar, to have 60 feet long by probably 15 feet wide of roofing area. That's a lot of water to run through what looks to be about a 2" pipe. Last year was an aberration, and we had slow, steady rainfalls in July and August (plus it was far wetter than normal). Usually, though, we get downpours for a few minutes and then no rain for another week or two. I'm wondering what size "spillover" hose I would need.
Of course, I can always hope that someone just donates a 500 gallon tank and let all the water run into it (wouldn't that be sweet!) but I'm not counting on it.
Mike