Do you live in a community that is pushing rain barrels to help with the environment? I do. How much help is a rain barrel? Kansas City's 10,000 rain barrels and rain gardens sounds like they will save the old part of town's aging sewer system, prevent flash flooding, allow the home owner to save a bundle on the water bill, and turn the city into a lush summer time garden. The benefits listed on the local rain barrel site also lists as a prime benefit, the feeling of doing something for the environment and the visible rain barrel will also let the neighbors know that you are environmentally conscious. Our former mayor, Emanuel Cleaver III, now a US congressman, also touts the rain barrels in a TV ad that appears several times a week.
Put some numbers to the rain barrel binge, and the only significant result is likely to be the warm fuzzy feeling one gets believing they are doing something for environmental protection. On the other hand, the rain garden, if it collects a thousand gallons of water or more, might be significant in helping to control water runoff and allow your yard to absorb enough water to make your trees' roots happy for a week. The little 20 to 50 square foot rain garden at the end of the downspout will harm the environment more than help it. The extra 60 seconds it takes to mow around the miniature rain garden will do more harm by polluting the atmosphere with your smoky lawnmower than the 30 to 50 gallons of rain water absorbed will help.
Decide for yourself the benefits to yourself and the environment by knowing the facts instead of feeling pressured by ads, neighbors, or environmentalists' uninformed guilt motivation. Here are some numbers to consider for the 30 to 50 gallons of runoff saved or stored by a typical rain barrel or mini rain garden.
A quarter inch of rain will fill a 50 gal. Rain barrel. (¼ inch of rain = 36 cu. in. per square foot of area covered by a roof. 316 sq. ft. of covered area will provide 6.6 cu. ft. of water, X 7.5 gal. Per cubic ft. = 50 gal. ) Typically, each home downspout will drain 300 to 500 sq. ft. of house area. Unless the ground of your community is already rain soaked, the ¼ inch of rain will be absorbed by the ground with little runoff, so the only value of the rain barrel is the value of the 50 gal. of water that you can use later. This amount of water will adequately water about 100 sq. ft. on a dry day or fill your watering can about 25 times to water pots and flower boxes.
If you live in an area that restricts outdoor use of water, this amount of water might be significant, so put in two or more rain barrels if you can. If you are never or seldom water restricted, make your choice based on the economic value of the water to you.
My water costs me 1.2 cents per gallon. My sewer charge, figured by my water meter is 1.4 cents per gallon. This makes the value of a full rain barrel $1.30. (2.6 cents X 50) If it fills four times each month, the monthly value is $5.20. ( If it fills more than four times a month, there is probably enough rain so I don't need a rain barrel.) If I use the water eight months during the year, the total value is $41.60 per year. Churches in the area are creating a social event making rain barrels. The charge to participate is $35 resulting in a fine rain barrel with a hose bib faucet and a covered top complete with mosquito netting. Ad my $2.00 for gas to drive the 10 mile round trip and the value of my 4 hours of time which I have bought for myself by paying my neighbor boy $40 to mow my yard, and I am now at a two year break even on my investment vs value. Don't even think of recovering the value of pre-made rain barrels I've seen advertised for $85 to $250. Then there is the cost to the community for TV and news paper ads.
The time it takes to properly use the recovered water can either be added to the cost if the task is burdensome, or it can be added to the value, if the routine of dipping or slow draining the barrel is a pleasant gardening pastime.
Now to evaluate the environmental impact beyond your cedar privacy fence. Let's assume that the rain barrel is made from a recycled barrel. If a new barrel is used, the negative impact of the manufacture of the barrel must also be considered. So we will work only on the value or problem of the rain water itself.
