Evaluating Rain Barrel Storm Water Management Effectiveness across Climatography Zones of the United States

Storm water management is becoming increasingly important as communities seek to mitigate the problems of accelerated storm water runoff. Using rain barrels to capture roof runoff is one strategy being advocated, but to be effective, this requires a beneficial use for the captured water such as garden irrigation. A previous analysis of this strategy based on the meteorological conditions of Cleveland, Ohio indicated that this would only yield a modest runoff reduction. The results presented here extend analysis to the wide range of meteorological conditions experienced across the continental United States. Theoretical rain barrel performance at seventy locations was evaluated using 2000–2009 daily precipitation records and local growing season durations. Simulations indicated that rain barrel performance would have been highly variable. The use of 235 L (64 gal.) rain barrels would have achieved total roof service area runoff reductions of 3 to 44%. The largest reductions would have occurred in southwestern states. The smallest would have occurred in southeastern states. While accomplishing these reductions, the rain barrels would have satisfied 5 to 73% of the irrigation demand of $13.9{\mathrm{m}}^2$ ($150{\mathrm{ft}}^2$) gardens. The assessment method and results presented should help communities evaluate the potential effectiveness of rain barrels and help establish storm water management program priorities.