Let it snow, let it flow, let it slow

What does all this year’s snow mean for water managers?

The Boca dam is used to control outflow to Boca Reservoir along the Truckee River system. Photo credit Richard Bednarski.

Ski resorts all around the Lake Tahoe region recently finished off the season strong with the latest closing date in years thanks to the record snowpack. But as summer (and summer heat) arrives, the region’s snowpack is now melting and heading downstream – and all that water needs to be managed somehow and by someone.

Meet Dave Wathan, Reno’s chief deputy watermaster. He works in the Federal Water Master’s Office, which manages the rights and regulations of the Carson and Truckee river systems, as well as operations at Lake Tahoe. 

“We determine how much water should be released or stored based on the operating rules in the system,” Wathan explained.

The operating rules he mentioned are outlined in the Truckee River Operating Agreement, which spells out how much water gets used for what purposes and where. For the Truckee River system, that means managing a system of lakes, reservoirs and canals that are used for everything from fisheries and agriculture, to municipal growth and hydroelectric power generation.

If it sounds like a big job, it’s because it is.

“We manage all the water in Lake Tahoe and [the] Truckee River system: storage, releases – managing water from all the reservoirs. Sometimes that means having to shut off some waterflow in drier years, because there’s just not enough to meet everyone’s demands. And in big years like this one, being careful not to overfill, while still trying to store up to the fullest capacity.”

History and indigenous implications

The Reno Water Master’s Office was created in 1926, in response to White settlers who began irrigating the land for agricultural use.

“There was a lot of unchecked water use,” Wathan said, “So the federal government filed a quiet title action to get an understanding of what water rights existed on the Truckee River system.”

That was one reason. The other, according to the U.S. Water Master’s Office website, was “as a means to help end rancorous legal disputes over water supplies.”

Engineers and surveyors penciled out how much water landowners could siphon out of the Truckee, but it wasn’t long before water levels began falling downstream at the Pyramid Lake Paiute reservation.

The Paiute tribe were granted senior “legal” rights to Truckee River water in a 1908 U.S. Supreme Court decision, known as the Winter’s Doctrine, giving the tribe the most senior claims on the Truckee.

“It’s basically the best priority, and it predates all the other rights on the system,” Wathan explains.

Relevant Reading: ‘Prove it or lose it.’ How tribes are forced to fight to secure senior water rights

While Native American tribes are entitled to some of the nation’s oldest water rights, they also have to legally quantify how much they need. Most tribes have never had their rights quantified, however, and that means federal law can undermine these rights, as we’re seeing in the Colorado River Basin. The U.S. Supreme Court last month ruled 5-4 against the Navajo Nation, throwing out a lawsuit from the tribe that tried to force the government to assert their water rights.

Since Native Americans claim senior priority over the water, every entity that comes after them consequently is granted junior rights. According to the University of Nevada, Reno’s Western Water Law: Understanding the Doctrine of Prior Appropriation, junior rights are often associated with municipal, environmental or recreational uses, and are fulfilled only after all senior rights have been met. Wathan said these are the entities whose water flow must be shut down in drier years.

“If there’s insufficient flow in the river to satisfy everybody’s demand, we shut off most junior rights first… that’s one of the hardest part of the job,” he said.

Daily operations

So, how does Wathan and other water managers take all this information into account? It all starts with a morning report that shows the amount of water residing in each reservoir, the category of the water, and where it will go.

Most years, that means monitoring weather reports, forecasting snowmelt and managing flood controls. During years of drought, it becomes more about making sure the watershed is healthy with sufficient levels across the board.

But this doesn’t mean an excess of water makes the job of the watermaster any less tricky, like we’re seeing with this year’s historic levels of Sierra snow.

“This year, we went from empty reservoirs to reservoirs spilling over. Managing reservoir operations can be a little more difficult in the big years,” Wathan said.

In a perfect world, Wathan said they’d fill each reservoir with the very last possible drop – but this is difficult, if not impossible, to achieve.

“That, combined with meeting downstream demands, staying within flood control criteria and depending on who you are and what you want, sometimes you’re not happy. It’s hard,” Wathan said.

A complex system, and the “education problem”

As to be expected, Wathan said increased development and users on the system make water rights more complicated still.

“Water is becoming less for agriculture and more for municipal uses. Then we have to consider things like habitats and fisheries, which is another big part of the job. Managing flows for fish and for the Paiute tribe, meeting everyone’s flow regimes is another thing added to the system.”

Managing the competition for a limited resource with various purposes is as difficult as it sounds. It feels in some ways, almost like a game – and partly, because it is.

A screenshot of the Missouri River Basin Balancer game, developed by the U.S. Army Corps of Engineers.
A screenshot of the Missouri River Basin Balancer game, developed by the U.S. Army Corps of Engineers.

In 2013, a team at the US Army Corps of Engineers created an online flood control game, called the River Basin Balancer Game. The user controls river operations with various objectives in mind, including flood control, hydropower, irrigation, water supply, recreation, wildlife, and water quality.

After a particularly snowy and wet winter (sound familiar?) the Missouri River Basin experienced major flooding in 2011, causing substantial damage, and the loss of many homes and farms. 

“Releases from the reservoir had to be made, and people just didn’t understand,” said Army 

Corps Engineer spokesperson Eileen Williamson. “There was an education problem. We wanted to tell people that managing the system is hard, but we’re doing it with a purpose.” 

This is where Williamson and her engineering team came up with the idea of presenting risk communication within the context of a game.

 “This allows us to communicate with the public about the complexities of the system, and the options available for mitigating risk,” Williamson said.

You can play the game online and see for yourself how tricky these management decisions can be – especially when you consider not just the various uses, but also the multiple operating agreements that must be followed.

“It’s not that we’re making decisions on a whim or on a guess,” said Dave Wathan, Reno’s chief deputy watermaster. “It might not make everybody happy, how we operate, depending on who you are and what you want, but our answer is always, ‘Well, this is how we’re required to operate.’”


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