Thankful on 37 gallons of water a day
November 24, 2011 § 11 Comments
You know how everyone always says there’s no way Angelenos could live on local water alone?
I had to test this assumption as my warm-up to a standard Thanksgiving exercise, naming something I’m grateful for: freshwater and all the lovelies it supports, in the myriad chain of life descending from the availability of freshwater.
There are obvious lovelies – cottonwood, willow and sycamore trees along riparian corridors.
And the well-known extirpated and endangered freshwater species – steelhead trout, salmon…
Or the less obvious – cuties like the turbid-delta-dwelling vaquita porpoise, who are squeezed to less than 250 individuals in the Gulf of California, thanks initally to habitat loss and now more hazardously, gillnet/trawler entrapment. Of course there’s skepticism regarding the loss-of-habitat angle, after all the Colorado River Delta only shrank when Mexico lost 90-95% of Colorado River flows, or as the Center for Biological Diversity says: “the (vaquita) also suffers by living in a habitat that is today a shadow of its former self. The Colorado River, once a raging torrent that fed a lush floodplain at the delta, has been reduced to a trickle by dams and water diversions to neighboring southwestern states.”
So yes, I am grateful for these wonders – and wonder about our assumptions of need, and the impacts we make to watersheds near and far, and to their beings. Which brings me back to that original question: can Angelenos do without imported water?
Just for chuckles I added up the “native safe yield” of urbanized Los Angeles County water basins. (You can find data in the Groundwater Assessment Study at the MWD.) They pencil out at 413,287 Acre-Feet/Year of withdrawals. Native safe yield is based on precipitation/runoff-based recharge – not imported water banking. It’s what we could reasonably use based on available recharge*. This number doesn’t exclude contaminated groundwater and also doesn’t include the potential gain of reused/recharged treated wastewater.
I then got figures for Los Angeles County population, and subtracted the cities that aren’t in the urbanized basin covered by the groundwater basins I added up. Sorry, Malibu, Palmdale et al, you’re out. My adjusted population number was 9,889,546.
413,287/9,889,546 = 0.04 AF/person/year
When adjusted to gallons/person/day (g/p/d), that comes to:
“Whoa, Nellie!” you might be thinking. After all, the average Angeleno uses between 96-150 gal/person/day, according to whose figures you use. And, I grant you, this doesn’t factor in agricultural or industrial uses of water, which are also essential.
But for domestic water use, I say yes. Or at least, we can get pretty damn close. As at least half of our consumption goes to lawns, the average Angeleno can right away cut down to 48-75 gal/p/day just by converting to native landscaping, a point brought out in many blogs, including Chance of Rain and Wild Suburbia.
Now I’m a renter and don’t see my water bill, so I can’t tell you how virtuous, or viceful, my consumption habits are (I do like long baths). But my mother’s high is 40 gal/p/d – and I’ve seen her water bill – her low has been as low as 20 gal/p/d. What can I tell you? She is an ardent practitioner of drought-tolerant landscaping and a child of the New Mexico desert. Yet she grows apricots and blackberries, and even has a small pond in her yard.
Anyone thinking this is a freakish anomaly should see the statistics for personal water consumption world-wide. More fun facts accumulated from trolling the internet:
|Daily Per Capita Consumption (Average)|
|Israel||56-64||(based on two cities)|
|SE Queensland, Australia||43||(high-55, low-29)|
|Barcelona||29||(down from 35 in 1999)|
|Palestine (West Bank)||10-12|
Note that Spain, particularly Barcelona, Queensland, and Israel/Palestine are relatively comparable in climate to us. Especially Barcelona.(Sources: Israel & Palestine, Spain, England-Germany, India, Barcelona, Australia)
Here’s how your average Englishman/woman pulls off this low water lifestyle:
|England Per Capita Consumption||g/day|
|Kitchen & Other||16.6|
|Baths & Showers||8.7|
(Same source as link to England-Germany above)
Know what made me laugh – besides the nervous laugh contemplating the discipline of a 9-gal shower? The UK agency that published this report took the tone of, how is it that our water consumption is so much worse than other countries in the European Union? Meanwhile here in the US, Albuquerque in 2001 described its per capita reductions in consumption - to 135 gal/p/d – as a cheering achievement (“Progress: Better”). And in Los Angeles, water managers write of demand and need, promoting desalination(1,2) and those inexorable water deliveries that are a major player in putting salmon and vaquita porpoises on the endangered species list. And next up: the Mojave River aquifer(links 1,2). But why do we define need by this apparently overstated “demand” and not the finite stuff, the “native safe yield?”
Indeed, it’s as if we have no concept of reasonable use, of accounting for our impacts. As if lawns that seem to be more labored over than enjoyed matter more than the possible extinction of entire species. For that, I’m sure we can find a way to live with 9-gallon showers.
*And I’m thinking that if we zoned lot coverage limitations for development based on the presence of higher permeability soils, and restored floodplains(you knew I had to say it somewhere, right?), we probably could recharge more – increasing our native safe yield, but that’s math for another day.