PROGRESS IN GEOGRAPHY ›› 2021, Vol. 40 ›› Issue (8): 1371-1385.doi: 10.18306/dlkxjz.2021.08.010

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A coupled surface water-groundwater model and its application in a large-scale hill-plain region

SUN Qingyan1(), LU Chuiyu1, GUO Hui2, YAN Lingjia1, ZHANG Bo1   

  1. 1. State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China
    2. Heilongjiang Provincial Water Conservancy and Hydroelectric Power Investigation, Design and Research Institute, Harbin 150080, China
  • Received:2020-12-10 Revised:2021-03-03 Online:2021-08-28 Published:2021-10-28
  • Supported by:
    National Key Research and Development Program of China(2016YFC0401404);Applied Technology Research and Development Program of Heilongjiang Province(GA19C005);National Natural Science Foundation of China(51509264);National Natural Science Foundation of China(51879066)

Abstract:

The complex physical geography and human activities in large-scale hill-plain regions increase the difficulty of hydrologic cycle research and water resources evaluation and management. As an important tool for basin or regional hydrologic cycle simulation, the coupled surface water-groundwater model provides convenience for solving many hydrologic and water resources problems in large regions. To address the conflict between precision and efficiency of modeling, a new semi-loose coupled mechanism was proposed in the study, which embeds the 3D finite difference groundwater flow numerical model into a semi distributed hydrologic model (MODCYCLE). The mechanism abandons the current popular spatial and information conversion method between hydrologic response units (HRUs) and groundwater grid cells, but establishes the spatial association of subbasins and grid cells and the real-time information exchange between surface water and groundwater systems. The model was built and applied in the Sanjiang Plain. The calibration and validation of the model show that it has the ability to simulate the past and predict the future of the hydrologic cycle. Finally, the relationship of surface water and groundwater in the Sanjiang Plain from 2002 to 2014 was analyzed by using the model output. The results show that the increase of precipitation and agricultural irrigation led to an increase of 651 million m3/a of soil water storage in the whole region, but reduced the reserves of surface water and groundwater by 99 million m3/a and 303 million m3/a respectively. The increase of precipitation did not improve the attenuation trend of water resources caused by the rapid increase of water consumption. There were significant differences in the precipitation recharge coefficient and base flow index in different regions, which were the result of the combined action of natural and human factors. The results can provide references for the research of hydrologic cycle and the evaluation of water resources in this region.

Key words: coupled surface water-groundwater model, semi-loose coupled mechanism, large-scale region, hydrologic cycle, MODCYCLE, Sanjiang Plain