Utah State Engineer | 2023

Water Resources
Water Intelligence:
Connecting the Dots Between Snowpack and Streamflow
in Mountainous Watersheds
The Logan River is fed by a combination of surface
water and water stored in underground structures
known as karst hydrology. In the spring, snowmelt
feeds the river; but for the rest of the year, it is primarily
fed by groundwater that enters the river channel via
karst conduits.
The dilemma is that there is no clear understanding
about how varying snowpack levels affect karst
storage and how that storage influences streamflow.
With climate variability and growing demand on
water supplies, experts agree that we need a better
understanding of how karst watersheds feed the rivers
and streams that provide our drinking water and
irrigation supply.
“Snowmelt-driven, karst-fed watersheds are not
well understood because conventional groundwater
modeling techniques do not work in mountainous, karst
terrain,” says Dr. Bethany Neilson, a professor of civil
and environmental engineering and a leading expert on
cold-weather watersheds.
Measuring how much of the river’s total flow originates
as karst storage is not a simple task. Neilson and her
colleagues are working to change that. For nearly a
decade, they have been collecting streamflow data
throughout the Logan River watershed. But streamflow
only tells part of the story. So in the fall of 2022,
they began collecting additional data derived from
chemically analyzing water samples from the Logan
River and its headwaters. Identifying chemical tracers
in the samples allows researchers to predict where the
water comes from and get a rough estimate of how long
it has been in storage.
By combining historical snowpack data and streamflow
data with the new hydro-geological data from the
chemical analyses, the researchers can develop a new
modeling tool that establishes connections between
snowpack variability and the amount of groundwater
and streamflow available for use in the Logan River.
These new modeling tools will help bridge the gap in
our knowledge of karst watersheds and give water
managers tools to make data-informed decisions.
Experts at the Utah Water Research Laboratory are searching for ways to decrease drought
and adapt to water depletion.
Streaming Wars
Historic drought and a chronic overuse of resources
is depleting the flow of the Colorado River. Utah,
along with six other states, depend on the river for
drinking water and daily use. Experts at the Utah
Water Research Laboratory are searching for ways to
decrease drought and adapt to water depletion.
UWRL Director Dr. David Tarboton and his student
Homa Salehabadi published a paper in the Journal of
American Water Resources Association on plausible
severe drought scenarios in the Colorado River
basin. The drought scenarios were updated to reflect
recent years by considering historical flows, treering
constructions, and climate change. The models
indicated that more severe droughts are likely to occur.
“Our generation will be defined by how we adapt,
how we experiment, how we jointly learn, how
we collaborate, how we cope with numerous
uncertainties, and how we pursue goals,” Rosenburg
said. “We want to find more sustainable and equitable
river management. To do this, we are working with
managers, stakeholders, and experts to adapt Colorado
River operations to declining basin flows and reservoir
storage.”
Professor Bethany Neilson is leading an NSF-funded study to better understand the water sources that supply the Logan
River Watershed in Northern Utah. Her research will help define how a changing climate will affect watersheds that
depend on seasonal snowmelt.
“These results indicate a need to rethink Colorado
River management and operation to be prepared for
future droughts,” said Tarboton.
Associate Professor David Rosenberg has also
dedicated years of his career to Colorado River
research. He studies ways to adapt basin depletions
to available water by using models of the Upper and
Lower Basin depletions as well as how to adapt to
low river flows. Rosenberg is also finding new ways
to conserve water used from the Colorado River in
irrigation and everyday life.
Dr. David Tarboton (left) Director, Utah Water Research Laboratory
Dr. David Rosenburg Associate Professor, Civil and Environmental
Engineering
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