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

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