This model simulates the reduction of water deliveries under a water conservation implementation plan. It is assumed that conservation measures are funded by the water supplier using funds driven by water demands, which creates a feedback loop in the model. Water demands drive the income for the supplier to provide the conservation measures. Increases in conservation also causes the net revenues used to pay for conservation to decrease. There are 4 components to this algorithm:
- Estimate housing growth
- Estimate cash flow for a conservation program
- Estimate the amount of water conserved
- Estimate the resulting water demand after conservation
Estimate housing growth
This subroutine estimates growth in population as a measure of housing units, which are divided into types of dwellings like single family houses and various sizes of apartment buildings. The growth is estimated using a History Generator, which generates stochastic time histories of variables. A stochastic time history is a random time history that is generated according to a specified set of statistics. This history generator is set to use a "random walk" to generate a random time history of housing demand, which influences the growth of units.
Estimate cash flow for a conservation program
This subroutine keeps track of the cash flow for a governing entity that is providing conservation vouchers to the populace at a cost to the entity. It is assumed that revenues are generated using a tax structure on the population and is supplemented by a 3rd party (to further promote conservation). If the cash flow approaches zero, conservation measures are reduced in the water conservation routine.
Estimate the amount of water conserved
This subroutine simulates the rate of implementation of conservation measures, which is partially a function of the cash flow of the governing entity that oversees conservation. It is assumed that these measures have an expiration, which means that eventually, a home owner could revert back to a non-conservation type facility in the future causing the total number of accumulated measures to be reduced in the population. Additional measures must be added to overcome the expiration losses. This is done using a reservoir element.
Estimate the resulting water demand after conservation
This subroutine estimates the total water demand before and after conservation measures are applied. Water demand is a function of an assumed unit demand rate and the current population size.