Tuesday, January 10, 2006
Saving rain
I bought a rain barrel for the front yard. It was from a seasonally existing garden store that mostly featured rain barrels- dozens of them. My 60 gallon barrel had "cut carrots" written on the side with grease pen. The store added two spigots, one low and one high on the barrel. I cut a hole in the screw lid that the downspout fits into.
Our city allows rain barrels without a building permit, so long as they are on the ground, height to width ratio less than 2, and under 4000 gallons (!). (Now that is saving for a non-rainy day!)
I got it too late in the season to do much useful watering with. So far, I have used it mostly for rinsing out the compost bucket. The kids will have fun with it this summer, sporadically over-watering the garden.
How long will it take to save enough domestic water to off-set the ecological footprint of a plastic rain barrel?
Ecological footprint analysis:
(footprint values from “Radical Simplicity” by Jim Merkel)
20 pound, plastic barrel, used previously as food packaging
Estimated benefit: 400 gallons/year, or 33 gallons per month (about 10 barrels full of useful garden watering per year, water that would have come from a domestic water supply otherwise)
Water cost: $0.0031/gallon (water in + sewer out [which one has to pay whether it went down the sewer or not])
Economic benefit: $0.105 per month
Footprint benefit: $0.105 * 157 sq.yd/$ = 16.4 sq.yd
(alleviates the need for that much resource to provide domestic water)
Economic cost: $50
Economic pay back: $50/($0.105/month) = 476 months, about 40 years (!)
Footprint “payback”: 20 lb plastic * 331 sq.yd/lb / 16.4 sq.yd = 404 months, about 33 and a half years (roughly equal to the economic payback, so the economics are roughly in line with the footprint)
The footprint “payback” could be less if the barrel is credited as used (about half the footprint, so payback in half the time)
Intangibles: Eyesore? Status symbol (acquired for the “wrong” reasons)? Educational/fun for kids? A measure of independence from the grid? Emergency backup water supply?
Like many of the things that I have considered to reduce impact, this has a long payback time (however, not quite to the seventh generation), which some may consider marginal, or negative. The only measure sure to have a smaller footprint is to use less.
copyright 2006 by Milliwatt
Our city allows rain barrels without a building permit, so long as they are on the ground, height to width ratio less than 2, and under 4000 gallons (!). (Now that is saving for a non-rainy day!)
I got it too late in the season to do much useful watering with. So far, I have used it mostly for rinsing out the compost bucket. The kids will have fun with it this summer, sporadically over-watering the garden.
How long will it take to save enough domestic water to off-set the ecological footprint of a plastic rain barrel?
Ecological footprint analysis:
(footprint values from “Radical Simplicity” by Jim Merkel)
20 pound, plastic barrel, used previously as food packaging
Estimated benefit: 400 gallons/year, or 33 gallons per month (about 10 barrels full of useful garden watering per year, water that would have come from a domestic water supply otherwise)
Water cost: $0.0031/gallon (water in + sewer out [which one has to pay whether it went down the sewer or not])
Economic benefit: $0.105 per month
Footprint benefit: $0.105 * 157 sq.yd/$ = 16.4 sq.yd
(alleviates the need for that much resource to provide domestic water)
Economic cost: $50
Economic pay back: $50/($0.105/month) = 476 months, about 40 years (!)
Footprint “payback”: 20 lb plastic * 331 sq.yd/lb / 16.4 sq.yd = 404 months, about 33 and a half years (roughly equal to the economic payback, so the economics are roughly in line with the footprint)
The footprint “payback” could be less if the barrel is credited as used (about half the footprint, so payback in half the time)
Intangibles: Eyesore? Status symbol (acquired for the “wrong” reasons)? Educational/fun for kids? A measure of independence from the grid? Emergency backup water supply?
Like many of the things that I have considered to reduce impact, this has a long payback time (however, not quite to the seventh generation), which some may consider marginal, or negative. The only measure sure to have a smaller footprint is to use less.
copyright 2006 by Milliwatt
# posted by Theepdinker @ 7:42 PM 
