Monthly Variation

In some demand sites, such as industrial sites, water use may remain constant throughout the year, while other demands may vary considerably from month to month. If the demand is constant throughout the year, leave this line blank. Otherwise, enter the percentage of annual water used in each month. The percentages will also be used to convert the annual pollution generated into monthly amounts. The variation should reflect the weighted effects of all users within the demand site. In estimating monthly variations for a demand site, historical patterns can be reviewed. If such records are unavailable, the user can reference demand sites with similar properties. The twelve monthly coefficients must sum to one hundred percent. If demand does not vary, all months are assumed to use the same amount, according to the number of days in the month. For example, the default annual share for January is 31/365=8.49%, whereas February is 28/365=7.67%. Depending on the setting in Basic Parameters, either the monthly variation is the same for all branches underneath a demand site or each branch within a demand site can have a different monthly variation.

Annual water demands are the requirements for final water services in industry, agriculture, domestic and other purposes. WEAP allows for three adjustments--demand site losses and reuse, and transmission link losses--to reflect more accurately the actual supply requirement needed to meet the demand for water services.

Entered on: Data View, Branch: Demand Sites, Category: Water Use, Tab: Monthly Variation