Mining companies were the first big water users in many of the western states, and much of the West’s water law today is based on dividing up mountain streams to run the high altitude mills that separated rock from ore. Water rights were allotted on a first-come, first-serve basis, which worked for miners and ranchers both: the oldest claims got their water first. Prior appropriation is one basic tenet of western water law. The second tenet is beneficial use–if you don’t actually use your water, you’ll lose your rights.
In Colorado, the water courts were set up shortly after statehood to adjudicate water rights. The Tribes had been moved onto reservations, so the miners, ranchers and ditch companies filed for water rights and claimed nearly all of the surface water.
Fast forward a hundred years. Mining claims played out and the mines closed. Since water rights specify a location, amount and date, those high altitude rights couldn’t be sold and were abandoned. Today only a few percent of the population lives on ranches, but ranchers and ditch companies still own most of the water. Cities grew later, and are having a heck of a time finding adequate water supplies because the surface water was claimed long ago, and owned by people who use the same irrigation systems their great grandfathers used. Thanks to the beneficial use clause, there’s little incentive for people who own early rights to conserve water. (If you don’t use your rights, you lose them, and a water right is a terrible thing to lose.)
When we go back to our total water use chart, you’ll notice that most of our water is used for irrigation. It’s the green bars.
Most of the irrigated acreage lies west of the Mississippi, so part of what these green bars reflect is what happens when the right to use water is privately owned and based on prior appropriation (where the earliest rights get their allotment first). In the West, the irrigators got the water and the political power both: the senate and congress of western states are packed with ranchers and old ranching families. And yet you can see from the chart, if irrigators (green) became 15% or 20% more efficient, it’d be the same as if every city (purple) cut its water consumption by 50%.
My, what a web we weave, when water management is governed by politics and law instead of science.
The water consumption seems very high for thermoelectric power generation. I wonder if you meant hydroelectric power?
Oddly, it’s thermoelectric. Hydroelectric is strictly non-consumptive. AO