I participate in CoCoRaHS (http://www.cocorahs.org/), an organization
that collects daily precipitation observations from a rapidly growing
network of nearly 10 000 volunteers in the U.S. (Please consider
joining!) After the daily report has been submitted the acknowledgment
page appears and it contains some sort of anecdote, which changes
periodically. Below my signature is the one that appeared today.
It's nice to see that this anecdote is entirely metric (with but one
exception), as is our National Weather Service. Ironically, CoCoRaHS
requires non-metric values from its volunteers; everything is measured
in inches on their reports.
I have my Davis Vantage PRO 2 weather station set up to read out in
metric units and must then do a conversion to submit my precipitation
reports. Since NWS keeps its records in metric units, it would be nice
if CoCoRaHS migrated in that direction. They could start by allowing
metric data submission as a option and then migrating their volunteers
toward using metric rain gauges, etc.
The anecdote reproduced here then would be immediately relevant to the
volunteers, since one liter is the same as a millimeter of rain falling
on one square meter of surface. And of course one cubic meter is the
same as 1000 liters.
My records show that my 100 hectare farm received 1208.3 mm of rain last
year, a droughty year since the normal for this area is closer to 1500
mm. Still, that means that 1.2 million cubic meters of rain fell on my
farm in 2008, enough to "support" 1200 people. That's the beauty of the
metric system -- ease of calculation. So one can calculate the area of
some location in square kilometers and then look at the annual rainfall
there. Every millimeter of rain that fells on each square kilometer of
that location is the amount needed by one person -- one to one!
My mode of getting that water to them was provision of timber, eggs, and
cattle as well as potable runoff (downstream and via aquifers).
Jim
Water Footprint
The minimum water that each person requires, on average, for drinking,
hygiene and growing food is about 1,000 cubic meters per year. That's
about 2/5 of an olympic size swimming pool. Because the distribution of
global water resources varies widely, some people get much more than
this and some people get less.
Researchers have recently developed the concept of a "water footprint".
As indicated on the water footprint web page
(http://www.waterfootprint.org), “The water footprint of an individual,
business or nation is defined as the total volume of freshwater that is
used to produce the goods and services consumed by the individual,
business or nation.”
You can figure out your own water footprint using the calculator (quick
and more extensive versions) on this site as well learn the total water
required to produce various products. Some interesting facts about our
water use from the water footprint web site:
* *The production of one kilogram of beef requires 16 thousand
litres of water.
* *To produce one cup of coffee we need 140 litres of water.
* *The water footprint of China is about 700 cubic meter per year
per capita. Only about 7% of the Chinese water footprint falls outside
China.
* *Japan with a footprint of 1150 cubic meter per year per capita,
has about 65% of its total water footprint outside the borders of the
country.
* *The USA water footprint is 2500 cubic meter per year per capita.
In addition to the water footprint web site, check out the August
2008 issue of Scientific American to learn more about the global
variability of fresh water.
--
James R. Frysinger
632 Stony Point Mountain Road
Doyle, TN 38559-3030
(C) 931.212.0267
(H) 931.657.3107
(F) 931.657.3108
