Exploring the impacts of warming induced cryosphere changes on surface and groundwater storage in the Heihe river basin

Amanda Triplett1, Laura Condon1
1Department of Hydrology and Atmospheric Sciences, University of Arizona

The Heihe River Basin (HRB) in Northwestern China depends heavily on manmade and natural storage like surface reservoirs, rivers, and groundwater for economic and environmental functions. The Qilian mountain cryosphere is integral to recharging these storage supplies. Climate change driven shifts in high elevation precipitation patterns and storage are expected to have significant impacts on water supply in the HRB. For example, the strengthening East Asian monsoon has caused a slight increase in the amount of rainfall. Additionally, warming temperatures have raised the snow line and accelerated the melting of glaciers and permafrost, altering the characteristics of runoff. To address the impacts of these cryosphere changes, we built a hydrologic model using ParFlow-CLM of the middle HRB, which encompasses over 90% of all water usage. Using this model, simulations were run to test how storage changes in the mountains impact the storage reservoirs in the valley. First, we used historic streamflow times series and increased and decreased flow into the middle HRB by factors of 5, 10 and 15% to represent the possible range of runoff fluctuations. These flow alterations were performed alongside warming and drought perturbations to domain climate forcings. The scenario results will then be examined for the magnitude of impact that these changes in cryosphere storage have on surface and groundwater storage in the middle part of the basin. Ultimately, this analysis can be used to examine the impacts of climate change in the cryosphere on the drought resilience of arid valley regions such as the HRB.

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