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All Topics | Topic "Losses"
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Author Message
Sandra Lanini

Subject: Losses   
Posted: 12/8/2006 Viewed: 23379 times
Losses Sandra Lanini Lanini <a href="mailto:s.lanini@brgm.fr">s.lanini@brgm.fr</a>Hello,

My WEAP model computes a Water Demand of 44.8 M.M3 and a Supply Requirement of 81.3 M.M3, although I set the losses in Demand site to 45 (percent). How does the option "Losses" work ? What number should I enter to have a Supply requirement equal to Demand*1.45 ?

Thanks for your help

Sandra
Jack Sieber

Subject: Losses   
Posted: 10/11/2007 Viewed: 23374 times
Losses Jack Sieber jsieber <a href="mailto:jack.sieber@sei-us.org">jack.sieber@sei-us.org</a>Sandra,

With Demand Site losses in WEAP, the formula for Supply Requirement is

Supply Requirement = Demand / (1 - Loss Rate)

With a loss rate of 45% and Demand of 44.8,

Supply Requirement = 44.8 / (1 - 45%)
= 81.45

In other words, if only 55% of the supply will reach the demand site, then 81.45 * 55% = 44.8 will reach the demand site.

If you want

Supply Requirement = Demand * 1.45

this means that 1.45 = 1 / (1 - x). Solving for x, you find that a loss rate of 31% will cause the Supply Requirement to equal 145% of the Demand.

Jack
Topic "Losses"