Go With the Flow: USU Researcher Examining Water Flow to Support Ecosystems in Great Salt Lake Basin

The terminal Great Salt Lake basin is a complex water system comprising rivers, wetlands and the Great Salt Lake. Meeting water needs requires collaboration among researchers and water managers to coordinate efforts to facilitate deeper understanding of systems while accounting for all the water users in the basin.

One important “user” is the environment itself. River and wetland ecosystems throughout the basin rely on water at certain times, with specific magnitudes, to support all the species that call them home. However, many places don’t have the data required to fully understand the relationship between streamflow and wetland and river ecosystem health.

Belize Lane, an associate professor at the Utah Water Research Laboratory, is leading a research effort to leverage ongoing Great Salt Lake water conservation efforts to also support river and wetland ecosystem health throughout the Great Salt Lake basin. A Functional Flows Framework has been developed for the Great Salt Lake basin to characterize how often, how much, for how long, when, and where flow is necessary to support aquatic ecosystem health.

Functional Flows Framework

Five metrics are used to describe natural streamflow: frequency, magnitude, duration, timing and rate of change. These are all pieces of a streamflow hydrograph (or streamflow over time). Streamflow changes naturally with the seasons, and this variability supports specific river processes, including biogeochemical, geomorphic and ecological processes.

In highly seasonal climates like Utah, many aquatic organisms are adapted to the natural seasonal and interannual variability in hydrologic patterns. Fish like the Bonneville cutthroat trout are cued to the timing and rate of change in streamflow that tells them when to move upstream to spawn. The flows upstream provide the best habitat conditions for spawning and rearing.

The functions a river provides depend on the flow, but when it comes to managing water to protect these functions, water managers don’t always have the data they need for a specific site. This is particularly important where diversions or dams have altered streamflows and ecological processes are no longer natural.

“The idea of functional flows is that, if we can summarize which parts of the flow hydrograph are most important for keeping ecosystems healthy, we can set management goals in the absence of more detailed, intensive studies,” Lane said.

Lane and her team began by meeting with stakeholders across federal, state and local groups invested in environmental water management. They laid out their proposed framework and asked for feedback. Then they developed algorithms to calculate the annual functional flow metrics from gages that measure natural flow regimes over a range of wet to dry years.

The next step involved machine learning to predict functional flow metrics at all the stream reaches in the Great Salt Lake basin. The purpose is to get estimates in places where data or gages aren’t in place.

By linking ecological processes to the natural flow, the project connects water quality, water quantity and wildlife. This will help managers assess tradeoffs among ecological and societal needs as water makes its way to the lake.

“I think it’s one of those amazing opportunities in research where there is real potential to achieve a win-win,” Lane said.

Real Numbers for Real Wildlife Needs

One of those wins comes from a fisheries lens.

“As a fisheries biologist, we can do all sorts of habitat work. We can go out and sample and monitor the populations, but without water, we don’t have a fishery,” said Paul Thompson, the assistant chief of habitat with the Division of Wildlife Resources.

Many times, he goes to the table with water managers knowing the fisheries need more water but not knowing how much.

“This project will actually identify the flow amounts in all of the streams in the Great Salt Lake basin considering different aspects of the hydrograph,” Thompson said. “This will allow water managers to understand what amounts are needed to maintain healthy fisheries.”

Utah fisheries play an important role in both the statewide and local economy. Blue ribbon or destination fisheries bring in millions of dollars, according to Thompson. He also emphasized the importance of maintaining healthy native fish populations.

“If we can work cooperatively with these numbers that the functional flow project is going to generate for us, we can highlight fish needs as well and try to maintain adequate water to maintain healthy populations,” Thompson said.

The data from the functional flows framework will show water needs from all different areas of the Great Salt Lake basin’s ecosystem, which excites Thompson.

“A lot of times when water decisions are made, wildlife are not part of the consideration,” Thompson said. “So, we’re trying to highlight that a little bit more.”

Building on the Framework

The project is a result of many heads and hands coming together across Utah State University campus and state agencies, including the Utah Department of Natural Resources and Division of Water Quality.

This collaboration is vital to achieving water management goals, Thompson said, emphasizing the importance of discussing state needs with university experts.

“Without partners,” Thompson said, “none of us in the state system would be successful in doing our jobs.”

Lane’s project is part of the Great Salt Lake Basin Integrated Plan, which was created by the Utah Division of Water Resources to understand the human and ecosystem water needs throughout the Great Salt Lake basin, including rivers and wetlands.

She hopes the outcomes from this project can encourage managers to think about the timing and rate of water releases to the Great Salt Lake so additional environmental benefits to rivers and wetlands can be achieved along the way.

“By considering water for the environment as another important water user,” Lane said, “we could do a huge amount of additional good with the same resource.”

More information can be found in the UWRL Annual Report.