Current and Past iUTAH Research Projects
iUTAH’s research portfolio is extensive and spans a diverse array of disciplines and interdisciplinary collaborations. Learn more about iUTAH research. Below are some highlights of current and past research efforts carried out by our participants:
Where is the Nitrogen in Utah’s Streams Coming From?
Air pollution that is in rain, snow, and dry particles can affect the biology and quality of stream ecosystems. iUTAH postdoctoral researcher, Dr. Steven Hall’s work confirms that both urban and mountain snow in Northern Utah contains the same components that are in PM2.5, the fine particulate matter that is of the greatest health concern with respect to air pollution. This demonstrates that local air pollution has a widespread environmental impact. Despite differences in air pollution in the Salt Lake, Cache, and Heber valleys, similar amounts of nitrogen were deposited in those areas during the winter of 2013-14.
Dr. Hall has found there is ample nitrogen in Utah’s urban streams, but air pollution isn’t the main culprit. Hall’s data show that only a small amount of the nitrogen in precipitation actually ends up in streams. Most of the nitrogen is taken up or removed by plants and microorganisms. Rather, other urban sources appear to be the dominant contributors of nitrogen in streams. In Salt Lake City's Red Butte Creek, stream nitrogen peaked following inputs of urban groundwater. Measurements of nitrogen isotopes in streamside plants showed differences in nitrogen composition between plants in the mountains and those in urban areas. This suggests a shift in nitrogen sources and cycling as streams enter urban areas. The amount of nitrogen being measured is not directly hazardous, but can contribute to numerous changes in our aquatic ecosystems. These include shifts in biological communities (the identity and abundance of species) and the increased growth of algae.
New Computer Software Helps Scientists See How Everything in Nature is Connected
Water touches everything. Farms, households, businesses, and nature all depend on water – and each of these also affects how water reaches the other entities that depend on it. As society makes greater demands on Utah’s water resources, scientists increasingly are asked to predict how the natural water cycle and our engineered water systems will respond to pressures such as population growth and climate change. What must Utah do to adapt to changes in snowfall or stream flows? How can we meet the needs of a population that could double in the next 35 years?
To make these predictions and begin to work toward solutions, scientists use mathematical “models” that account for the various factors that influence water flows and uses. These models – actually sophisticated computer programs – must be complex enough to describe how scientists believe that natural and built water systems behave, yet simplified enough that they can be useful to decision makers who must make choices with data that may be limited or incomplete. These data, called input variables, are processed in mathematical equations to predict the consequences for desired outputs, i.e., the products and services that society and nature need from water. For instance, a hydrologic model might take in data on rain and snowfall, air temperature, solar radiation, etc., as input variables to produce outputs such as river flows, evaporation, and plant uptake.
Scientists who study different domains of the water system develop unique models that can answer the questions that matter to them. For example, a hydrologist may want to predict how stream flows will decrease over the summer after the snow melts, while an industrial engineer might want to predict how a new technology can reduce the amount of water needed daily to cool an electrical plant. Their respective models both rely on information about water availability and desired outputs, but they probably won’t account for all of the factors that are part of the other’s model. To answer the larger questions about how Utah can respond to changes in water supply and demand, more holistic models are needed that cover multiple domains of the water system.
That’s the problem Caleb Buahin is working on. Caleb, a postdoctoral researcher with the iUTAH project at Utah State University, has developed a flexible software framework called HydroCouple (Figure 2) that allows scientists to bring together models from different domains and scientific disciplines. This approach, called component-based modeling, allows for the communication and exchange of information during calculations. It allows scientists to test and refine hypotheses about how water systems behave by experimenting with different models using the same framework.
Caleb’s current work involves coupling together models that simulate the natural and built portions of urban water systems. By working with the City of Logan and using aquatic and climate data from iUTAH’s Gradients Along Mountain to Urban Transitions (GAMUT) network, he is able to examine present and future water capacity related to the cities’ stormwater system. An example output from his work shows the interactions between the canal system and the engineered stormwater infrastructure.
By demonstrating how this framework can be useful for bringing together models and data for different aspects of Utah’s water system, Caleb is creating software tools and guidance that can help other researchers evaluate not just water systems but other natural resource systems. In so doing, scientists will be able to avoid the pitfalls of studying parts of a problem independently, without considering the important ways that different resources affect each other and our future.
How Thirsty are the Trees we Plant in Our Own Front Yards?
Trees provide welcome shade and can reduce the need to water lawns in the hot Utah summer. But trees also need water themselves. Understanding how mature urban trees use water can help give municipal land and water managers a better idea of how to conserve water. Quantifying water use by the most common tree species may prove particularly valuable because forests do not naturally occur in Utah’s urban areas. Planted trees within the city are maintained by irrigation, requiring large amounts of water. iUTAH researcher Dr. Richard Gill and his graduate student, Michael Bunnell, are studying urban tree sites in the Heber Valley of Wasatch County, Utah. This valley is a rapidly developing landscape where populations are projected to grow 90% by 2030. With this urban expansion and human population growth, more trees are expected to be planted within the region, placing a greater demand on the valley’s water resources.
Bunnell’s initial findings show a trend in planting deciduous tree species such as maple in new developments within this region. These species inherently use more water than conifer species such as blue spruce. Looking at particular tree species, Bunnell’s findings suggest that the biggest determinant of water use for a single tree is the anatomy of the sapwood tissue. For example, some trees conduct water through all living tissue, while in others, water movement is constrained to the current year’s growth only.
In a region where water resources are limited, it is important to understand the influence of planted forests on water use. To achieve this goal Gill and his students are collecting sap-flux measurements to quantify daily and seasonal patterns of transpiration in dominant landscape trees occurring within suburban reaches of the Heber Valley. Ultimately, this research will assist urban land managers in better identifying water-efficient tree species and aid in making decisions about planting densities.
Breakthroughs in Aquatic Microbiology Advance iUTAH Research
Streams are teeming with many different kinds of bacteria, but until recently the technology has not existed to let scientists understand how the species composition of microbial communities is linked to water quality. Researcher Zachary Aanderud and his PhD student, Erin Jones, are studying the importance of bacteria in stream environments and their role in water quality for iUTAH. Breakthroughs in DNA sequencing technique allow iUTAH to be part of a new wave of aquatic ecology studies now taking place. Previously, scientists could describe stream bacterial activity only in terms of total carbon – basically measuring the amount of bacteria, but not which kinds are present. Identifying the species present is useful because different types of bacteria are able to create different biochemical compounds, including ones that are considered pollutants. We now are able to analyze a stream's capacity to produce any number of pollutants, based on molecular activity represented in bacterial genomes.
Their first study involved collecting water samples from pristine, high-elevation sites sites to low urbanized, low-elevation sites in the Logan, Red Butte, and Provo watersheds. In the past, their lab had measured levels of a single bacterium, E. coli, at these sites, and recorded a definite increase in this species from high elevation to low elevation. The more urbanized sites showed a decrease in bacterial diversity – there were fewer species, and certain species tended to grow more dominant as they looked further downstream. Upon closer examination, the shift in bacterial community happened above heavy urbanization in all three watersheds. Instead, the shift corresponded to sites immediately downstream of dams (First Dam in Logan, Red Butte Reservoir in Red Butte, and Jordanelle Reservoir in Provo). This change occurred before there were significant changes in E. coli levels.
This data, paired with water chemistry data collected by iUTAH researchers, will give huge insights to how bacterial communities interact with other water quality variables. By collecting samples during different seasons of the year we can see if these trends are consistent across different weather and flow patterns.