Watershed Symposium 2022

What are the observed trends and future projections of the climate signals? And how would the snowpack, soil moisture, and streamflow change in the future? Let's discuss results using climate and hydrologic models (i.e., VIC, and RAPID) for the Jordan river basin (i.e., Spanish Fork, Provo, Utah Lake, and Jordan River).

In the recent years, we have witnessed mega-drought events and stresses on precious water resources and the environment. The observed climate and hydrologic data show changing patterns in rain and snowpack, record high summer temperatures, variation in soil moisture contents, very low water reservoir levels, lowered groundwater, and resulting streamflow. The consequences of events have resulted in observed historical low water levels in the Great Salt Lake. For policymakers and water professionals, it is important to answer some of the key questions such as (1) what are the observed climate change signals in water basins in the state of Utah, and (2) what are the potential future projections of the climate change and hydrological responses, (3) how resilient are our water resources against changing climate and extreme events, and (4) what are potential adaptation strategies to achieve the goals of water resilience.

This presentation attempts to answer part of those questions in two parts. The first part of the presentation will include an analysis of historical data on the observed temperature, precipitation, snowpack, and streamflow in several parts of Utah. The analysis results will reveal the rate and trends in the changes of climate stressors on water resources. The second part of the presentation will cover future climate projection and impacts on water resources, including precipitation, snowpack, soil moisture, and streamflow. The analysis will be based on multiple Global Climate Model results statistically downscaled in the finer resolutions of 6.25 km, forced run the Variable Infiltration Capacity model (VIC), and Routing Application for Parallel computation of Discharge (RAPID) models.

This presentation covers the larger Jordan river basin (includes Spanish Fork, Provo, Utah Lake, Jordan River), one of the most populated basins in the state and one of the primary sources of water supply to the Great Salt Lake. The models were calibrated from 1980 to 2004 and validated for 2005 to 2020. It includes continuous daily simulations of multiple climate projection inputs until the end of the 21st century. This presentation is based on one of the ongoing and in-house modeling projects of the Utah Division of Water Resources to evaluate the impact of climate change in GSL watersheds. Water policy professionals will have an opportunity to get informed about signals and trends of climate change and its impact on water resources at the regional level. Technical water professionals will have an opportunity to learn the type and sources of data, methods, and models that can be applied to large basin-level water resources assessment.

The following are learning objectives from these presentations: 1. Basic understanding of main climate signals and trends considered in water resources assessment. 2. Become informed about climate model projections at the basin level. 3. Gain an understanding of how large-scale hydrological models are developed to simulate climate change impact at the basin level. 4. Understand how resilient our local water bodies are against the changing climate.