Groundwater Numerical Simulation Of The Middle Reaches Of Heihe River Basin

Heihe River is the second longest inland river in the northwest China. It flowsacross three provinces, namely Qinghai, Gansu and Neimenggu, which constitutes aespecially important strategic location. However, the middle and lower reaches of HeiheRiver Basin are extremely dry, where the local water resources can hardly cover thedemand of economic development and ecological balance. Conflicts between differentdistricts and different kinds of water demands have long existed in the region. Thenational water diversion plan conducted in July,2000has greatly relieved the conflicts,but was not enough to settle all the disputes. Also, the national water diversion plan maycause new challenges. So it is important to build a groundwater simulation model of theHei River Basin for further supporting water allocation studies.This study explores the conversion relationship between the river water andgroundwater in the middle reaches of Heihe River Basin after the national waterdiversion plan was conducted. An all-around conceptual model of hydrogeology is builtafter analyzing the natural geology, economic development, hydrology, water utilizationbackground of the Hei River Basin.Visual MODFLOW2011is used to build the groundwater numerical simulationmodel of the middle reaches of the Heihe River Basin. The middle reach of the HeiheRiver is simulated using the STR package, which can soundly depict the real conversionrelationship between the river water and groundwater. The model can also simulate theoutflow of Zhengyixia, which enables further studies on the water allocation of theHeihe River Basin.The simulation results of the model accord with measured results. The calibratedmodel is used to simulate the water diversion situation. The results indicate thatdifferences in groundwater transferred to river water between wet years and dry years isa major cause that lead to the phenomenon “It’s harder to reach the water diversion goalin wet years than in dry years”. The efficiencies of the three existing water diversionplans are compared, which offers scientific support for improving the water allocationof the Heihe River Basin.