AN INTEGRATED HYDROLOGIC MODEL OF THE NORTH CHINA PLAIN AND IMPLICATIONS FOR SUSTAINABLE WATER RESOURCE MANAGEMENT

North China Plain (NCP) is the largest alluvial plain of eastern Asia covering an area of 320,000 km2 with a population over 200 million. Groundwater overdraft has caused rapid water level declines in the NCP. Although a number of hydrologic models have been developed in the past for the NCP, they either focus on the groundwater component only or are at local scales. Integrated hydrologic modeling encompassing all major hydrologic processes in the land phase of the hydrologic cycle has never been attempted for the entire NCP. For a large region such as the NCP, an integrated hydrologic modeling approach considering all the hydrologic components will reflect the hydrologic system more realistically and also provide an internally consistent means of calculating groundwater recharge to the aquifer. This study applied the integrated hydrologic modeling software – MIKE SHE coupled with MIKE 11 – to explore the hydrologic system in the NCP. The model successfully reproduced the observed groundwater levels, surface water discharges, and several other indicators, and provided the total water budgets of the entire system. Sensitivity of the integrated flow model to several key parameters, including subsurface hydraulic properties and boundary conditions, was investigated. The results indicated that the model is sensitive to hydraulic conductivity and river-aquifer exchange leakage coefficient. More than 80% of the total inflows leave the system through evapotranspiration (ET), and more than 20% are pumped out of the system. There is a deficit in the total water budget which is compensated by aquifer storage depletion. For sustainable water development, ET must be effectively reduced since it is the most significant outflow and depletion component. As for the pumping, more emphasis should be put on the optimization and redistribution of pumping locations and strengths. The integrated modeling approach incorporating both surface water and groundwater allows for impact assessment of a wide range of water resource management options in the NCP.