Study of groundwater using visual MODFLOW in the Manas River Basin, China

For effective groundwater management of a basin, it is essential that a careful water balance study be carried out. A three-dimensional transient-state finite difference groundwater flow model is used to quantify the groundwater fluxes and analyze the dynamic changes of groundwater level. After monitoring groundwater levels for 43 typical observation wells through a simulation study of the groundwater flow model with a depth of 300 m, results reveal that the study area has a lateral recharge of about 3.57 × 109 m3, which makes up 79.08% of the total recharge; total evaporation is about 1.81 × 108 m3, which makes up 3.77% of the total discharge. The balance of groundwater is negative, with a recharge and discharge difference of −2.81 × 108 m3. The correlation coefficient between the observed head and the calculated head for the simulation period is greater than 0.81, indicating the simulation results are satisfactory. The maximum groundwater drawdown is 26.59 m and the rate of the groundwater drawdown is 0.15 m/d during normal operation of the pumping well.