My county requires rainwater management to be incorporated into lot plans for new construction if a certain percentage of the lot is impervious. This seems a sensible measure.
We are under the impression that rain gardens are the only approved method for managing runoff (if a percolation study determines that the site's soil can support one). Rain gardens benefit the community by reducing erosion and filtering pollutants.
It seems to me that rain barrels can achieve the same benefits. The only significant differences between the mechanisms that I can think of are
- the storage capacity and
- retention time.
Rain gardens "store" water temporarily and have a much higher capacity; rain barrels store only about 55 gallons but can hold that water indefinitely.
Because I'm an avid gardener, I'd much rather have rainwater available for watering my garden and reduce my reliance on municipal water. There is also some concern that rain garden performance degrades over time unless well-maintained. I don't think there's a similar risk to rain barrels, but if there were I imagine it'd be much easier to rectify a failing rain barrel than a failing rain garden.
Can rain barrels be considered to be suitable substitutes for rain gardens? Why or why not? Under what conditions?