Watershed Symposium 2024

Summary:
Great Salt Lake is shrinking, yet cities along the Wasatch Front and in the lake's drainage basin continue to grow unabated. Both the lake and cities need water to prosper, setting up an existential crisis. Is it possible for the needs of the lake AND Utah's growing population to be met? The answer is YES, and this presentation will explore how.

Full Abstract:
In a world experiencing rapid population growth and limited water supplies, many cities have successfully eliminated the need to develop additional supplies as their population grows. This is known in academic circles as “decoupling” or breaking the traditional link between urban water demand and population growth. Successfully decoupling municipal and industrial (M&I) water demand from population growth has allowed these cities to continue to grow and prosper despite diminishing water availability and climate change stresses. In order for Utah to continue to grow and not cause further harm to the GSL and other aquatic ecosystems, Utah’s communities need to follow the proven decoupling model. This presentation will explore successful examples of decoupling in the Southwestern United States and assess how cities in Utah measure up and what needs to be done to ensure a bright future for all who rely on the state’s precious water resources.

Summary:
Dust blowing from dry lakebeds annually darkens the snowpack of the Great Salt Lake Basin. The darkened snow absorbs more sunlight, resulting in earlier snowmelt. Here, we have used a combination of fieldwork, satellite observations, and modeling to quantify the impact of dust snowmelt, in hopes of improving water supply forecasts in the region.

Full Abstract:
Seasonal snow in the Great Salt Lake Basin (GSLB) provides critical water resources for human infrastructure and local ecosystems alike. The GSLB snowpack has a first order influence on water availability to 2.7 million Utahns and provides the main surface inflows to the Great Salt Lake. Snowmelt rates are primarily controlled by snow albedo, which is impacted by surface darkening from light absorbing particles (LAPs). In the Wasatch Mountains, the primary LAP constituent is dust originating from dry lakebeds across the eastern Great Basin. Dust accelerates snowmelt, adding uncertainty to streamflow forecasts. Despite this, the impact of dust on snowmelt timing is not well known in the GSLB and is not directly accounted for in operational models. Here we present three years of research targeted at quantifying the spatial and temporal distribution of dust on snow and its impacts on snowmelt rates and timing across the GSLB. Our work includes a time series of point-based field observations, analysis of 23 years of satellite remote sensing retrievals, and basin distributed process-based snowmelt modeling. Results reveal that dust impacts snowmelt annually, but with high variability year-to-year, and with no strong temporal trends in the last two decades. The annual impact of dust on snowmelt was quantified over two distinctly different water years (2022 and 2023) by running two model implementations with different albedo representations: 1) A standard time decay relationship representing clean snow albedo evolution, and 2) daily remotely sensed observed snow albedo from MODIS. Differences between model runs, evaluated by melt rates, surface water inputs, and snow depletion timing, reflect the influence of snow darkening on snowmelt across the basin. This approach has allowed us to parse out physical drivers of snowmelt and is the first study to quantify snowmelt acceleration due to dust over the GSLB.

Summary:
How much water is Utah actually delivering to the imperiled Great Salt Lake? Are we heading toward a healthy Lake or costly mitigation? In this workshop, we explore a new report showcasing sobering findings exploring the consequences drying up the Great Salt Lake could have on Wasatch Front residents’ health and the state’s pocketbook.

Full Abstract:
If the Great Salt Lake is in peril, Utah is in peril. Great Salt Lake water levels are on a long-term decline – due to decades of upstream water diversions and climate change-driven aridification in the basin – exposing a vast expanse of dry lakebed that contains a number of toxic components. This creates a looming public health and economic crisis for residents of Northern Utah and the Wasatch Front. What are the financial and public health impacts to the millions of Utahns living adjacent to the Lake if we fail to deliver enough water to address current lakebed exposure issues and prevent continuing decline? In this session we will explore findings from a year of research that has culminated in a revelatory new report showcasing sobering findings concerning the consequences that drying up the Great Salt Lake could have on the health of Wasatch Front residents and the costly mitigation measures that could be required to suppress dust if Utah doesn’t succeed in raising Lake levels. We will present findings from what is, to our knowledge, the largest and most comprehensive review of the medical science of public health impacts from Great Salt Lake lakebed exposure. We will summarize what hundreds of papers show are the many and serious health implications associated with exposure to lakebed dust, discuss the possible presence of overlooked toxins in Great Salt Lake dust and their likely impact, and compare this emerging health emergency to that of other desiccated lakes around the world. In an analysis of efforts to deliver water to the Great Salt Lake, we will explore how effective Utah has been in meeting targets to deliver an additional 500,000 to 1 million acre feet of wet water each year to the Lake – the amounts needed to raise the Lake to a minimum healthy level and prevent catastrophic dust storms. Finally, we will examine whether we are headed toward a future of mitigation, like Owens Lake, and provide an updated and more detailed estimate of the costs associated with keeping dust from a desiccated Great Salt Lake on the ground.