Climate Warming-Driven Changes In The Cryosphere And Their Impact On Groundwater-Surface Water Interactions In The Heihe River Basin
Presenter: Amanda Triplett1
Advisor(s): Dr. Laura E. Condon
1Department of Hydrology and Atmospheric Sciences, University of Arizona
The Heihe River Basin in Northwestern China depends heavily on both manmade and natural storage (e.g. surface reservoirs, rivers, and groundwater) to support economic and environmental functions. The Qilian Mountain cryosphere in the upper Heihe River Basin is integral to recharging these storage supplies. Sustained climate warming is driving shifts in high elevation water storage that are expected to have significant impacts on water supply in lower reaches of the Heihe River Basin. To examine the impact of these shifts, we built a hydrologic model using ParFlow-CLM of the middle-basin, where the majority of water usage occurs. Using this model, we ran five simulations from 2001 to 2011 to model the watershed response to the loss of glaciers, advanced permafrost degradation and projected temperature increases. We accomplish this by altering streamflow inputs to the model to represent cryosphere melting processes, as well as by increasing the temperature in the climate forcing data. Results show enhanced groundwater discharge when flow from the cryosphere is reduced, and increased infiltration when flow is increased. The Glacier scenario has a net loss to groundwater storage while the Permafrost and Combined have net gains. This shows that permafrost degradation has more of an impact on the system than glacial loss. This is likely due to greater total water added to the system, especially during high-recharge, winter months. Seasonal differences in groundwater-surface water partitioning are also evident between the scenarios. The Glacier scenario has the highest fraction of groundwater in streamflow in early Spring. The Permafrost and Combined scenarios meanwhile have the highest fraction of streamflow entering the subsurface in late Spring and early Summer. Ultimately, this analysis can be used to examine the cascading impact of climate change in the cryosphere on the resilience of water resources in arid basins downstream of mountain ranges globally.