Simulation of groundwater dynamics in the North China Plain by coupled hydrology and agricultural models

We simulated the effects of irrigation on groundwater flow dynamics in the North China Plain by coupling the NIES Integrated Catchment-based Ecohydrology (NICE) model with DSSAT-wheat and DSSAT-maize, two agricultural models. This combined model (NICE-AGR) was applied to the Hai River catchment and the lower reach of the Yellow River (530 km wide by 840 km long) at a resolution of 5 km. It reproduced excellently the soil moisture, evapotranspiration and crop production of summer maize and winter wheat, correctly estimating crop water use. So, the spatial distribution of crop water use was reasonably estimated at daily steps in the simulation area. In particular, NICEAGR reproduced groundwater levels better than the use of statistical water use data. This indicates that NICE-AGR does not need detailed statistical data on water use, making it very powerful for evaluating and estimating the water dynamics of catchments with little statistical data on seasonal water use. Furthermore, the simulation reproduced the spatial distribution of groundwater level in 1987 and 1988 in the Hebei Plain, showing a major reduction of groundwater level due mainly to overpumping for irrigation. Copyright  2006 John Wiley & Sons, Ltd.