Since an acre-foot is about 1200 m^3, then 75 000 000 x 1200 = 90 000 000 000 m^3 = 90 km^3.
In other words, an acre-foot is about 80 % as large as a cubic dekameter. Jerry ________________________________ From: John M. Steele <jmsteele9...@sbcglobal.net> To: U.S. Metric Association <usma@colostate.edu> Sent: Sunday, April 12, 2009 10:36:11 AM Subject: [USMA:44616] Re: Water, teraliters, was FPLA 2010 While I agree that would be better, the American West manages water rights in acre-feet. Here is a typical "managed river" report (Lower Colorado) in terms of water elevation in feet at each dam, release in cubic feet per second and water storage in thousands of acre-feet, all as hourly averages. . http://www.usbr.gov/lc/region/g4000/hourly/yester.html The Colorado is managed as upper and lower basins, and averaged over ten years, the upper basin must deliver 75 million acre-feet per annum to the lower basin. At the level of micromanagement above, I'm not sure the river can be described as "flowing" though, more a matter of "released." --- On Sun, 4/12/09, STANLEY DOORE <stan.do...@verizon.net> wrote: From: STANLEY DOORE <stan.do...@verizon.net> Subject: [USMA:44611] Re: Water, teraliters, was FPLA 2010 To: "U.S. Metric Association" <usma@colostate.edu> Date: Sunday, April 12, 2009, 9:06 AM You all state very well the difficulty in NOT using the SI. Acre-feet describes volume by area and depth. Although commonly used in hydrology, it is disconnected with the SI and not an understandable volume unit except for a few. River flow volume is not stated in acre feet but in gallons per second or cubic metres per second; so there is a disconnect. Use of the SI would solve the problem.. Software packages can determine the volume in a contoured lake periphery and lake bottom and therefore can compute the volume in cubic metres. It doesn't make sense to continue to use acre-feet for volume. Stan Doore ----- Original Message ----- From: John M. Steele To: U.S. Metric Association Sent: Sunday, April 12, 2009 7:57 AM Subject: [USMA:44610] Re: Water, teraliters, was FPLA 2010 I had never heard of that usage, but it is apparently true. If I append the word "oil" to a Google search on acre foot, I only get 7.6% as many hits. But many relate to barrels per acre-foot. Several calculate the "barrels" of rock in an acre-foot and calculate porosity. Without the word "oil," water use dominates and I can't find the wheat for the chaff. --- On Sun, 4/12/09, Martin Vlietstra <vliets...@btinternet.com> wrote: From: Martin Vlietstra <vliets...@btinternet.com> Subject: [USMA:44609] Re: Water, teraliters, was FPLA 2010 To: "U.S. Metric Association" <usma@colostate.edu> Date: Sunday, April 12, 2009, 7:19 AM I understand that the US oil industry uses barrels per acre-foot (where the “foot” refers to the thickness of the oil-bearing strata). If this is reduced to rational units, we get a dimensionless number which can be expressed as a percentage! ________________________________ From:owner-u...@colostate.edu [mailto:owner-u...@colostate.edu] On Behalf Of John M. Steele Sent: 12 April 2009 12:07 To: U.S. Metric Association Subject: [USMA:44608] Re: Water, teraliters, was FPLA 2010 Dear Pat, Let me guess. Before metrication, they used acre-feet (at least we do in the US ). 1 acre-foot = 43560 ft³ x (0.3048 m/ft)³ = 1233.5 m³ or 1.2335 ML or 1.2335 dam³. So it is an "almost familiar" size unit. The agricultural section of SAE recommends the cubic dekameter wherever acre-foot is now used (although I have never heard anyone in the US actually use it). --- On Sun, 4/12/09, Pat Naughtin < pat.naugh...@metricationmatters.com > wrote: From: Pat Naughtin < pat.naugh...@metricationmatters.com > Subject: [USMA:44604] Re: Fw: Re: Water, teraliters, was FPLA 2010 To: "U.S. Metric Association" <usma@colostate.edu> Date: Sunday, April 12, 2009, 3:03 AM Dear John, Thanks for the correction. I simply cut and pasted the article without reading it carefully. I will watch the 'Geelong Advertiser' more closely in future. By the way, the few water engineers that I know have developed a mindset where the unit megalitre is used for capacities and they have a sense of how big the dams in our system are, see http://www.barwonwater.vic.gov.au/index.cfm?h2o=services.water_levels , and they don't see a need to convert between megalitres and cubic measures of any kind; they just develop their megalitre mindset and then base their reference values using that unit. Another aspect to the use of megalitres is that there is no fear of large numbers. Water engineers, like many others, have simply chosen a unit where almost all, if not all, of the values they use daily are in whole numbers, which is one of the great strengths of the metric system. It is possible to choose prefixes for units so that there is never any need for fractions at all. See http://www.metricationmatters.com/docs/WholeNumberRule.pdf for some further thoughts on this issue. Cheers, Pat Naughtin Geelong , Australia On 2009/04/12, at 12:22 AM, John M. Steele wrote: Indeed, there is a prefix error. This "facts & figures" page http://www.barwonwater.vic.gov.au/cms/serveDoc.cfm?docId=24911 indicates Barwon water supplies 32000 ML of water annually, processes 21000 ML of sewage, and serves 270000 customers (that is apparently population, as household connections is less than half that, 131000). Thus average household use is therefore around 244 m³ per year. A thousand-fold error should cause a "whoa, wait a minute" response. I believe the fact that it didn't is adequate evidence that megaliters, gigaliters, and teraliters (even with "re" spelling) are not very intuitive units and throw a great cloud of confusion over any attempt to visualize or sanity check the amount. Any form of proper cubic measure, from 32 x 10^6 m³, 32 million cubic meters, 32000 dam³, 32 hm³, would be a more suitable way to convey this information, and be less likely to obscure a thousand-fold error. Teraliters are frightening. --- On Sat, 4/11/09, John M. Steele <jmsteele9...@sbcglobal.net> wrote: From: John M. Steele <jmsteele9...@sbcglobal.net> Subject: Re: [USMA:44564] Re: FPLA 2010 To: "U.S. Metric Association" <usma@colostate.edu>, pat.naugh...@metricationmatters.com Date: Saturday, April 11, 2009, 8:59 AM You have proven megaliters, gigaliters, and teraliters are used. That is a staggering amount of water given Geelong 's population. Where does it all go? Irrigation? If I compare with Detroit , private consumption and industry can't account for much. A volume of 32 TL/annum meant absolutely nothing to me, a completely incomprehensible number. Some manipulation led me to it being 32 km³ per year, giving me some sense of what you do to the river. It also works out to a withdrawal of 1015 m³/s. It still seemed large, so I compared it to the Detroit River (part of the connection between Lake Huron and Lake Erie , and the Detroit Water Dept, which serves a metro region of about 5 million people. The Detroit River flow varies typically from 4500 m³/s in low lake level years to 6500 m³/s in high lake level years. The Detroit Water department handles an average of 673 million gallons per day, by their figures. Converting, this is 0.93 TL (or km³) per year (29.5 m³/s) for 5 million people. That figure is reasonably consistent with my household use of 273 m³/year) As we use less than 1/32 the water for about 25X the population (is Geelong under 200,000?), I wonder if there isn't a prefix error in that news article. (If it isn't an error, you guys need more conservation effort!) --- On Sat, 4/11/09, Pat Naughtin <pat.naugh...@metricationmatters.com> wrote: From: Pat Naughtin <pat.naugh...@metricationmatters.com> Subject: [USMA:44564] Re: FPLA 2010 To: "U.S. Metric Association" <usma@colostate.edu> Date: Saturday, April 11, 2009, 12:00 AM On 2009/04/11, at 1:35 PM, Jeremiah MacGregor wrote: I can see where the terms megalitre, gigalitre and teralitre would be less cumbersome for the public then their equivalents of cubic dekametres, cubic hectometres and cubic kilometres. Dear Jerry and Stan, Here is an example of the use of gigalitres from our local paper, The Geelong Advertiser, from October last year. Barwon Water is our local water supply organisation as we get most of our water from the Barwon river.. http://www.geelongadvertiser.com.au/article/2008/10/24/26151_news.html Cheers, Pat Naughtin PO Box 305Belmont3216, Geelong, Australia Phone: 61 3 5241 2008 Metric system consultant, writer, and speaker, Pat Naughtin, has helped thousands of people and hundreds of companies upgrade to the modern metric system smoothly, quickly, and so economically that they now save thousands each year when buying, processing, or selling for their businesses. Pat provides services and resources for many different trades, crafts, and professions for commercial, industrial and government metrication leaders in Asia, Europe, and in the USA . Pat's clients include the Australian Government, Google, NASA, NIST, and the metric associations of Canada , the UK , and the USA . See http://www.metricationmatters.com/ to subscribe. Pat Naughtin PO Box 305Belmont3216, Geelong, Australia Phone: 61 3 5241 2008 Metric system consultant, writer, and speaker, Pat Naughtin, has helped thousands of people and hundreds of companies upgrade to the modern metric system smoothly, quickly, and so economically that they now save thousands each year when buying, processing, or selling for their businesses. Pat provides services and resources for many different trades, crafts, and professions for commercial, industrial and government metrication leaders in Asia, Europe, and in the USA . Pat's clients include the Australian Government, Google, NASA, NIST, and the metric associations of Canada , the UK , and the USA . See http://www.metricationmatters.com for more metrication information, contact Pat at pat.naugh...@metricationmatters.com or to get the free 'Metrication matters' newsletter go to: http://www.metricationmatters.com/newsletter to subscribe.
