Investigating natural relationships: Tracing water pathways in the Snowy Range Mountain

Wil Chapple with the distillation system at UW

Challenging traditional thought is part of what science is all about. For one EPSCoR undergraduate fellow, challenging historical assumptions about the natural water system is the focal point of his research.

 “We’re trying to understand plant-water relationships and determine if the water that trees are consuming is also the water that contributes to stream flow,” says Wil Chapple, one of the first undergraduate researchers for WyCEHG.

Wil started at the University of Wyoming as a history major, but today he is studying the history of glacial events in order to better understand the water system in the Snowy Range Mountains. There were three glacial events which shaped the types of soil in the Snowies. Wil believes that these different types of soil are part of the key to understanding the water system. His motive for studying the water system comes from a discrepancy between traditional thought and recent discoveries.

“There’s a traditional thought that current precipitation mixes with old precipitation and that trees consume this and that it is part of the stream flow,” says Wil.

Recent research from another university indicates that this may not be the reality. This research shows that plants may consume water stored in soil pores from past precipitation while new precipitation goes to stream flow.

“So, some of the water that comes in as precipitation might fill up that small pores in the dry soil earlier in the season and sit there, and later snow melt events might just rush right past the trees,” says Dr. Dave Williams, Wil’s mentor for the project. “During the summer, when the plants are taking up water, they might be slowly drawing on that water from soil pores and not from the snow melt.”

In order to study this phenomenon in the Snowies, Wil is collecting samples of snow to analyze the isotope signature of the precipitation.

One of Wil's research sites

“We’re using isotopes to trace water and how that water partitions differently depending on the history of the glacial events that created the soil,” says Dr. Williams. “If the soils have no effect on the way the water moves, then water that the trees are taking up and their isotope signature is going to be the same as what the signature is downstream.”

Isotopes are useful tracers because the origin, type and temperature of precipitation determines the isotope composition, thus precipitation events have different isotope configurations. The configuration of isotopes follow some patterns in that heavy water molecules characterize summer and fall precipitation compared to that of the winter and spring. The isotope composition of a compartment of water is determined by the ratio of heavy to normal atoms, which Wil will be analyzing to determine isotope signatures.

Wil will determine the isotope ratios using the Laser Spectroscopy Isotope Analyzer in the Stable Isotope Facility at UW. This equipment vaporizes water samples and measures the absorption of different wave lengths of light. Different isotopes absorb different light frequencies. By going back and forth between frequencies, it is possible to determine the ratio of heavy to normal isotopes in the water. Wil is preparing to analyze snow samples from the last few months, which have been collected every morning there is new snowfall.

As his research continues, Wil is also busy working on the proposal for this next stage of his project. This summer he aims to collect and analyze samples of soil, water from streams and lodgepole pine. With the deadline for the summer fellowship one week away, Wil is focused on showing what he has learned and where he wants to take his work.  

“It’s been a good experience so far,” says Wil. “I feel like I’ve only kind of dipped my toes in and hopefully this summer I will really get a taste of this research and field work.”

This project has given Wil a glimpse into the life of a water scientist and helped him get a feel for what graduate school might be like, but it has also allowed him to go beyond the theoretical knowledge of the classroom and into the application of science.

A second research site

“It feels good to apply my knowledge,” says Wil. “Last semester I felt like I really came out with a lot of tangible knowledge and it was refreshing.”

Part of this knowledge came from Dr. Larry Munn, who, as Wil says, is the soil guru of UW. Dr. Munn has spent most of his life studying and developing the knowledge about the distribution of soils from the different glacial events in the Snowies. His research has been instrumental in Wil’s understanding of the Snowies.

“We’re quite fortunate that Wil has been able to work with Larry,” Dr. Williams says.

As is the goal of all WyCEHG research, Wil’s project is a collaborative process. It brings together knowledge from various fields and experts, looks at the complexities of the natural water system and aims to shed light on how historical events shape the present.

“I think this project is really cool because it brings forth this long history of glacial events and how that’s shaping how water moves in the landscape,” says Dr. Williams.

Wil’s research will shed light on the water movement and add to the body of research challenging traditional assumptions about water systems.