Calculation of Municipal Demand

The total municipal demand (expressed in m3) is the product of specific municipal demand in l/capita/day, the numbers of days per month and the population of the settlement.

Both specific demand and population are developing over time and are thus subjects to forecasts.

The calculation of the development of specific municipal demand uses the following formula:

MWDn = MWDb* (1+G/100)N + S


MWDn = projected future municipal water demand in l/day per capita
MWDb = municipal water demand per capita for reference year
G = yearly Growth rate in %
100 = factor to convert from percentage to fraction
N = N = (2005 - reference year), for the next steps: N= 5 ( 2010, 2015 etc.)
S = sudden increase/decrease in l/day per capita

The monthly results of the absolute municipal demand figures are stored in table STP_MUNICIPAL.

Notes on Parameters:

Timestep N. Usually 5 years except for 2005. For that year, N is the difference between 2005 and the reference year for which billing data are applied.

Sudden increase/decrease refers to the period between the years for which demands are to be calculated. Since the time between the balancing years is of no interest, it is sufficient to enter S only for the balancing years. Usually this value does not apply to a large selection of Demand Centers!

The general concept of growthrate and migration is widely applied in the pre-processing module.