The Science & Politics Behind the Game - Water Rights
This is the first of a series of in-depth posts on the scientific and political background behind the game.
In California, water rights grant permission to divert water for "beneficial use". In the earliest days of the state, one major use was hydraulic gold mining, a process where high pressure water is sprayed from 6"+ diameter pipes to turn mountains into muddy water from which tiny gold particles could be filtered out.
The amount of gold yielded from hydraulic mining in 19th-century California would fill a small room, the amount of earth moved was large enough to cause small earthquakes. Today, some of the former mine sites such as the Malakoff Diggins are state parks.
Water rights were also granted for agricultural, industrial, hydroelectric, and urban uses. Today, the amount of water rights granted exceeds the average rainfall. To determine who gets water and who is left high and dry, California's complex system of water rights weighs many factors, the most common of which is age, or “first in time, first in right.” Water rights can be bought and sold, which is what Los Angeles did in the early 1900s to divert water from the Owens Valley.
The New California Water Atlas, a series of online interactive maps, has a map showing all water rights in the state. http://projects-ca.statewater.org/water-rights
More information is also available via UC Davis Center for Watershed Sciences' California WaterBlog.
In the Game
To keep things simple while conveying the basic ideas behind the system, in California Water Crisis, the twelve water rights are simply ranked 1-12 in order of seniority. During wet years all get water, but during dry ones only the lower numbered ones get them. Someone holding a low-numbered right will have a reliable source of water even in a drought, while those with many junior rights will have an unpredictable supply.
What about groundwater?
You're probably thinking, if California uses more water than there's rain, where does the shortfall come from? A lot of it is groundwater, which will be covered in a future update.