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The tragedy of a common resource: Water

How can engineers help reconcile short-term needs with the long-term common good?

Next to a town there’s a lake. People in the town rely on fish from the lake for food. So lots of people go fishing, and numerous professional fishermen make their living catching fish to sell in the town. Anyone can access the lake and can take as many fish as they like. But over time it seems the fish population has been dwindling. The fish are being caught at an unsustainable rate. So how does this play out?

Every individual and every professional fisherman has a strong incentive to meet his own short-term need. Families need to eat, and professional fishermen need income. So they each have an incentive not only to keep fishing but to catch as many fish as quickly as possible before they’re all gone. If they don’t, others will anyway. There’s no incentive for any individual fisherman to incur personal sacrifice when they know that their sacrifice alone will produce no meaningful change. So everyone keeps serving their immediate needs and eventually the lake is fished out, the resource is depleted, people are forced to move away, businesses close, etc.

It’s called the Tragedy of the Commons, the commons referring to the common resource, not commoners. It’s when people's short-term interests are at odds with the long-term common good.

So where is the Tragedy occurring with a common resource that we care something about? An obvious example is depletion of our groundwater.

If you run a farm, or an industry, or a city, and your surface water supply is getting unreliable, what are you going to do? More people, more water-dependent businesses, an increasingly unreliable surface water supply, droughts. Everyone’s thinking the same thing: We need to tap the groundwater aquifer. Like the fish in the lake, aquifers all around the western United States are being over-pumped. Short-term individual need is trumping the long-term common good.

And the damage can be permanent. When you over-pump groundwater, aquifers collapse and permanently lose storage capacity, which of course diminishes their ability to serve and sustain the population on the surface.

Many studies have shown that the way to avoid the Tragedy of the Commons is to privatize the resource. Why? Because to make a resource sustainable you need two things: 1) control and limited access, and 2) an economic incentive to operate the resource sustainably (i.e., to maximize wealth). A legitimate argument could be made that this should be the role of government, with the counter being that government has already presided over creation of the problem.

In any case, unlimited, uncontrolled access to a critical, shared, but diminishing resource sets the stage for the Tragedy of the Commons to play out. How do we make groundwater basins sustainable when there are already more straws in the ground than anyone can count, much less regulate….more fishing poles in the lake than anyone can count, much less regulate?

I don’t know the answer but I do know this: Anyone involved in any way with solving water and environmental challenges in the West in the decades ahead has the opportunity to enjoy about as meaningful, challenging, relevant and ultimately fulfilling a career as anyone on the planet. Where do you think the answers are going to come from if not from you?

Dave Bennett leads Stantec’s Water practice in the Western US.

Earth stripped of its water (left), all of the water on Earth (middle) and all of its fresh water (right), each accurate to scale. Image via Dave Gallo/WHOI.

It’s called the Tragedy of the Commons, when people's short-term interests are at odds with the long-term common good.

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