Numerical simulations for ground water withdrawal inversion in Beijing plain

Accurate measurements of groundwater withdrawal are essential for water resource
management. Measurement errors are unavoidable in Beijing plain areas due to human factors. A method was
proposed in the present study to inverse ground water withdrawal by groundwater flow numerical simulations.
A ground water numerical model for Beijing plain areas (minus Yanqing plain) was developed with the popular
 finite-element software FEFLOW. Sensitivity of ground water withdrawal to average groundwater level in each
 administrative county was used to adjust ground water withdrawal. Groundwater withdrawal was inversed
through artificial trials and errors by matching simulated and measured ground water levels, which were
obtained from 111 observation wells. With this method, estimated annual groundwater withdrawal in Beijing
 Plain was found to be 23.16×108 m³, 21.77×108 m³ and 23.44×108 m³ respectively in 2012, 2013 and 2014.
Simulated groundwater level fitted well with measured values in each county after inversion and the numerical
model could be used to simulate ground water dynamics in Beijing plain. The relationship between regional
 ground water level and groundwater withdrawal was analyzed for Shunyi County. These results will provide
decision support for county-based groundwater management in Beijing plain.