Prediction of water resources change trend in the Three Gorges Reservoir Area under future climate change

Abstract

In this study, the water intake module and the confluence module were added to the Community Land Model version 4.5 (CLM 4.5), forming the Community Land Model-Dualistic Water Cycle (CLM-DWC) model (land surface hydrological model). It solved the problem that the influence of human activities was not considered in the existing hydrological coupling simulation process, which so as to the inaccuracy of the simulation process. The CLM-DWC model was driven by the average results of five Global Climate Models (GCMs) ensemble to form the “atmosphere-land-hydrology” fully coupled model to predict the temporal and spatial variation trends of water resources in the Three Gorges Reservoir Area (TGRA) from 2021 to 2050 under Representative Concentration Pathway (RCP) 2.6, RCP4.5 and RCP8.5. In the future scenarios, in terms of spatial distribution, the runoff, surface water and groundwater all indicated the high at the belly of the reservoir and low at the head and tail of the reservoir, which were in good consistency with the baseline period. In terms of intra-annual distribution and inter-annual variability, runoff depth increases by 20.8 mm at RCP4.5 compared with the baseline period, and it tended to decrease under RCP2.6 and RCP8.5. At the same time, under the three scenarios, the average increase of surface water was 3.44 %, groundwater decreases by an average of 11.72 %. Accurately predicting the change trend of water resources in the TGRA under climate change has great significance for future water resources management and planning in the reservoir area.