The River Basin Model is a man-machine simulation model used to delineate the interactions taking place, within a real or hypothetical area, between the local water system and the economic, social and governmental activities of that area; it is a model of an entire regional system, with water a subsystem realistically interacting with all the other major subsystems, such as housing and transportation. The local Assessment Department is given the opportunity and responsibility for determining assessed values of property within the local dynamic system. The largest percentage of the revenues raised by local governments is from the real property tax. The value of real property in the model is determined by the normal workings of supply and demand. The Assessment Department may assess land and /or developments at any rate from zero to one hundred percent of their market value.