Study of Lehman Creek Watershed's Hydrologic Response to Climate Change Using Downscaled CMIP5 Projections

This study focuses on the climate change impact on the hydrologic processes at watershed-scale in a snow-dominant watershed, with bias-corrected climatic data from Coupled Model Intercomparison Project phase 5 (CMIP5). Lehman Creek, a typical snow-dominant watershed, located in Great Basin Nation Park, eastern Nevada, was studied. Quantile-Quantile (Q-Q) mapping technique was applied to three climatic variables, precipitation, maximum temperature and minimum temperature, from 12 Global Climate Models (GCMs), from CMIP5 data (BCCA, RCP6.0), with reference data of historical PRISM observations for 1981-2010 as baseline period. In order to study the hydrologic impacts brought by climate change, a physical-based distributed parameter hydrologic model was developed using Precipitation-Runoff Modeling System (PRMS). The bias-corrected climatic data of 12 GCMs for baseline period (1981-2010) and projected period (2011-2099) are the forces to drive the calibrated PRMS model to simulate the hydrologic processes. Results show that compared to historical period, both positive and negative changes could occur in long-term streamflow; decreasing trends were observed in summer season (June to October) and increasing trends in spring season (January to May). The greatest streamflow increase is noticed in April (6%) and decrease in June (5%). The results of the study may help water resources management with better understanding of climate change influence on the streamflow in Lehman Creek watershed.