Tragedy of the commons

Tragedy of the Commons is one of system archetypes. It is an economic theory describing a system with shared resource where the actors act independently according to their self-interest. Draining of the resource can cause their actions to behave contrary to the common good.

Introduction

You live in a smaller city where you own some land. As a landowner, you have the rights to use the water pumped up from wells on your land. Whenever you are in a need of water, you go and get it. As your family grows, you naturally need more water. But it's just few more people and there is enough water in your well. There are many other landowners in your city and each one manages his own water consumption. As your city and its population is growing, water usage rises as well. What you may not realize is the fact, that all the water from different wells throughout the whole city is part of a regional groundwater aquifer, so each landowner is pulling water from the same pool. After continual long-term growth of the water consumption, the city’s water supply reached levels that left the aquifer vulnerable to saltwater intrusion from the nearby ocean. Now the city is facing potential water shortages and possible destruction of the renewable water resource the city depended on.