Reservoirs and resources: Stewarding Utah’s waterways

Utah’s reservoirs are more than just scenic bodies of water — they are the lifeblood of the state’s agricultural industry, drinking supply and overall sustainability.   

Utah’s diverse geographic landscape is home to 137 reservoirs, each one playing a vital role stewarding the state’s water resources, including supporting its 10.5 million acres of agricultural land.

Patrick Belmont, professor of hydrology and geomorphology in the Department of Watershed Sciences at Utah State University, said reservoirs offer a buffer for agriculture.

“It’s hard to have a population anywhere near this size and be growing this amount of food if you don’t have access to water all throughout the year,” Belmont said.

Managing Utah’s water resources is a unique challenge due to the state’s diverse climate, spanning from the mountainous Wasatch Range to the arid desert.

“There’s a big gradient in terms of where our water is, and that also relates a fair bit to where our population is,” Belmont said. “We’ve got a lot of our population centers around the Wasatch Front, and that’s where a lot of our reservoirs are. A lot of other places — we just can’t have a large population because there’s no water to even dam up.”

Candice Hasenyager is the director of the Utah Division of Water Resources.

“Water in Utah is hyperlocal,” Hasenyager said. “It really depends on where you’re at, what your water resources are and what storage reservoirs you have. It has to be managed at the individual and local level.”

Utah reservoirs are currently 80% full on average, according to Hasenyager. This excludes some of the larger reservoirs such as Lake Powell, which is at approximately 35% capacity.

“We’re seeing really good reservoir levels because of the previous wet years that we’ve had,” Hasenyager said. “This is about 20% higher than normal due to that additional carryover from those earlier wet years.”

Snowpack, a metric that directly impacts reservoir levels, makes up 95% of the state’s water supply.

“Right now, our current snowpack statewide is about 92% of normal for this time of year, so definitely below where we’d like to see it,” Hasenyager said. “But if you look at the broader picture of the state, there’s definitely some regional impacts that are going on.”

According to Hasenyager, snowpack levels in Northern Utah are normal, ranging from 90% to 108%. In the central part of the state, snowpack is between 55% and 82% normal and is even lower in Southern Utah, ranging from 29–31%.

According to Belmont, there has been a greater fluctuation between delivery and melting of snow due to warmer temperatures, changing how reservoirs are managed throughout the year.

“Reservoir operators are starting to think earlier in the winter about how much water they should be diverting to fill the

eservoirs versus how much they should be passing downstream,” Belmont said.

During the spring, reservoir operators attempt to find the balance between storage and passage of water. In the summer, their focus shifts to responding to calls for water, using meters to ensure there is an adequate amount for the current year and a base fill amount for the next year.

“That can be a tricky game to play because if you go into a sequence of dry years, it’s not guaranteed you’re going to get the reservoir refilled the next year,” Belmont said. “So, they may scale things back a little bit if they see that they’re starting to run low.”

A key part of water resource management is mitigating the impact of inevitable fluctuations — conserving water usage allows for more water storage in reservoirs that creates a holdover for dry years and a greater reserve of groundwater.

“One of the best things that we can do is use less water,” Hasenyager said. “If we use less water, we’re making ourselves more resilient to any sort of fluctuations that occur.”

While reservoirs serve an important purpose, Belmont is concerned with potential risks they can cause.

“As humans, we’re really good at setting really narrow goals and achieving those goals,” Belmont said. “We wanted to store water. We’re really good at that goal, but then we often don’t think of a lot of the unintended consequences.”

According to Belmont, soil erosion caused by wildfires can lead to sediment entering reservoirs, which can have detrimental impacts on water quality.

“When that fills up the reservoirs, it can cost tens of millions of dollars to clean that sediment back out,” Belmont said. “Sometimes, it also just completely removes a reservoir from being able to be used for a while.”

Reservoirs have also been found to produce large amounts of methane, a strong greenhouse gas, due to carbon that gets stored and broken down in the reservoirs. They can also disrupt aquatic ecosystems and be expensive to maintain.

“The costs for that are starting to add up,” Belmont said. “I’m afraid we’re handing those costs off to younger generations without really dealing with them.”

From Hasenyager’s perspective, the mindset around water usage has changed significantly.

“In the past, we’ve seen a lot of effort to create new dams and reservoirs, and now it seems like we’re trying to figure out how to use our water as widely as possible,” Hasenyager said. “I’ve seen more of an emphasis on how we can conserve and use the water as best we can today.”

Such conservation happens at an infrastructural level.

“Looking at our housing types and our property, looking at how landscaping goes in and doing it right the first time to make sure we’re using low water use plants and drip systems,” Hasenyager said. “There’s been a significant investment into water and trying to help us create a more resilient water supply for our future.”

Belmont hopes to see a philosophical change in how humans steward the earth’s natural resources.

“The number one thing would be to tread much lighter and steward our environment with a much greater sense of humility — recognizing that we’re part of this ecological system and anytime we alter that system, there are going to be ramifications and some unintended consequences,” Belmont said.