Wednesday, February 24, 2010
What water?
Where’d the Water Go?
There are some legendary “wasters” of water. How about Celine Dion using a whopping 6.5 million gallons of water in 2007 at her home on Jupiter Island, Fla., according to a study done by the Palm Beach Post. Cry me a river! There’s also the estate of wealthy Atlanta investor Chris G. Carlos whose property consumed 440,000 gallons (1.67 million liters) in September 2007 alone. After a public outcry, Carlos dramatically reduced his monthly usage to just 12,000 gallons.
Some of our biggest and most unusual “wasters” of water aren’t all that glamorous. The Scientific American recently compiled a list of some interesting water sucks. Here they are:
1. Doing the Dishes: By Hand or Dishwasher?
A typical by hand session will go through about 20 gallons or so. But if you leave the water running while scraping at those last grisly bits on your fine china, you may use more than twice that amount. Modern electric dishwashers, in contrast, need less than 10 gallons (38 liters) per average load.
2. Washing the Car (and the Driveway)
According to a west coast chain, a home car wash can go through 80 to 140 gallons of water, whereas a wash at one of its garages will take about 30 to 45 gallons. Many professional car washes also utilize methods that recycle water.
3. Slipping Through the Cracks
A swimming pool naturally loses about 1,000 gallons a month to evaporation, although the local climate and the pool's overall surface area determines the amount that's actually lost. A bigger problem arises from the leaks that pools often develop during their lifetimes from cracks in a pool’s foundation, liner tears and pipe damage.
4. Lawn Sprinklers: Fountains of Backyard Verdure or Pernicious Aquifer Guzzlers?
The water sprinklers that keep our grass green and flowers growing can consume 265 gallons an hour. Landscaping usage generally rivals or exceeds estimates of what an average U.S. household uses daily. A good tip: unless you’re going to eat what you grow, don’t plant that which needs copious amounts of water to live.
5. Well-Watered Desert Resorts
You don’t see a lot of water around Las Vegas. The Venetian canals of the Bellagio, as well as the Mirage's water-and-fire volcano, seem to be on the “most wanted” list of water wasters. This is not as bad as it seems though. Apparently the Las Vegas Strip accounts for just three percent of local water use. Nearly 70 percent of the Las Vegas water supply goes toward irrigating the 60-plus golf courses and the many residential lawns in the area. Grow rocks; they don’t need so much water.
6. Biofuels' Hidden Downside
Just because biofuels burn cleaner than fossil fuels and therefore emit less carbon dioxide into the air doesn’t mean that there’s a dark side. Plant-power sucks up ridiculously large quantities of water compared with oil and natural gas production. For example, producing a gallon (3.79 liters) of corn ethanol consumes 170 gallons of water in total, from irrigation to final processing. Soybean biodiesel manufacture needs some 900 gallons of water per gallon of fuel. On the other hand, the water requirement to make a gallon of regular gasoline is just five gallons.
7. Agriculture in the Arid Southwest
much of the U.S. Southwest is a desert and about 90 percent of the Colorado River's water is today diverted into the Southwest for agricultural irrigation. It’s been estimated that almost half of the water could be lost through evaporation and seepage. Many farmers rely on flood irrigation, which, though inexpensive, is a highly inefficient means of delivering water to crops. The Colorado's dwindling water flow threatens the supplies of at least seven states; water rights are the new range wars.
8. Alfalfa Farming Woes
many think of alfalfa mainly in terms of the sprouts that end up on sandwiches, but most of the alfalfa crop feeds livestock. The relatively low-value crop uses up about a quarter of California’s irrigation water but contribute only 4 percent to the state's total farm revenue. The main issue is that farmers grow alfalfa year-round in what is essentially a desert climate in the southwestern U.S.
9. The Ruin of the Aral Sea
The Aral Sea in central Asia was once the fourth largest body of freshwater on the planet. Where did it go, did they drink it. Well sort of… But by siphoning off waters from the massive lake for irrigation, local farmers and governments in Uzbekistan and Kazakhstan have drained the Aral Sea to about 10% of its original size. The Aral has split into three parts, two of which are so salty that all the fish in them died!
10. Saving the Saddest for Last
Ah beer! It may be refreshing and cool but it's likely to leave you less hydrated than you were before you started. Alcohol is a diuretic, which means it makes you want to go. And when you go, you have to drink more water to make up for that which was spent. Alcohol suppresses an antidiuretic hormone called vasopressin that tells our kidneys to reabsorb and conserve water. The more you drink, the more the hormone level falls, and thus the more water you lose. Don’t blame the beer, it’s the dehydration.
Friday, February 5, 2010
Should there be a cistern in your future?
Cisterns on Sanibel
Cisterns have been used in many areas for centuries, predominantly in places where ground water is scarce, such as the Virgin Islands, Bermuda, etc. Even though Sanibel’s Island Water Association (IWA) appears to have access to abundant aquifer water, does it not make sense anyway to conserve rain water as much as possible? On Sanibel, wells into the aquifers are not allowed and many island homes use more water for landscape irrigation than they do for potable uses. So we’ve done a brief study of cisterns that could be used locally.
Since many homes on barrier islands, such as Sanibel and Captiva, are elevated on pilings or raised stem walls, they provide ideal areas for water storage. Cisterns come in many forms, so estimating the cost is difficult. Most literature I’ve come across refers to the cost of a cistern as being about $1.00/gallon. Cost for cisterns in the USVI, built as part of the home’s foundation, appear to run about $1.25-$1.50/gallon.
I’ve looked at a product called “Rainpillow”, which is essentially a plastic bag. These come in a variety of sizes (1,000-40,000 gal) and are lightweight (a 3000 gallon kit weighs a little over 100 lbs.). The costs appear to run from $2.50/gal (1,000 gallon kit) to $.60/gal (10,000 gallon kit).
This is based on the use of a 10000-gallon “Rainwater Pillow” (size is 23’ x 23’x 3’) as a storage device, as a model for our Sea Glass project, for example, since information is readily available for all required equipment, i.e. tank, filters, pumps, etc. Also, this size tank would most likely fit and could be set up under a raised stem wall foundation. I’ve been told from the company that it can be accessed through a 4’ x 4’ access hole. This projection is also based on the use of stored water for landscape purposes only. Accurate information on the cost of equipment necessary to make cistern water potable was not readily available.
While stored water can be easily treated to be used for “greywater” devices, it would appear that landscaping might be the most directly beneficial since there is light treatment involved and irrigation water, on Sanibel, has to come from the IWA. The IWA has stated that a typical Sanibel home with a “conservation” landscape package would use approximately 9,000 to 14,000 gal/month to support the landscaping. A key problem with water storage for landscaping is that during the “dry” half of the year, when irrigation is most important, the average monthly (November through April) rainfall is only 1.9 inches/month, according to UF extension service tables. One inch of water is collected at the rate of .6 gallons per square foot of roof area. So a 3,000 sq. ft. roof area will collect 1800 gallons of water at the rate of 1”/month.
Since the landscape area for a typical home in Sea Glass would most likely be smaller than a typical Sanibel lot, I’ve taken the liberty to estimate the landscape water demand at 6,000 gal/month. Under this scenario, it appears that the 10000-gallon storage tank would need replenishment water from the IWA for about 5 months of the six-month “dry” season. This replenishment would not be required during the months of the average “wet” season since the s month average is approximately 7.0 inches/month.
This is the 20 year projection for this system:
Total gallons of water collected from cistern: 1498400 gallons
Total supplemental irrigation water purchased: 188000 gallons for $752.00 (present cost)
Total system cost: $13,759.00
Cost of system per gallon/stored: $1.37
Cost of water per 1000/gallon: $9.18
The cost of water is approximately twice what the cost of the IWA would be as it is now. This could be easily offset if any type of rebate or tax credits were to be involved if forward thinking law makers were act as they should.
Jeff Good
Benchmark General Contractors, Inc.
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Cisterns on barrier islands
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