Numcrical Simulation Study Of Groundwater By Feflow In Baojixia Irrigation On Loess Plateau

Located in the central of Wei Bei loess mesa, Baojiaxia irrigation on loess plateau is arelatively shortage of water resource area. With the development of the research area,groundwater extractions also increase year by year and the status and future trends ofgroundwater resources become widespread concerned. Therefore,the study of dynamic typesand numerical simulation and prediction of groundwater in Baojiaxia irrigation on loessplateau has great theoretical and practical value for the sustainable use of groundwaterresources.This study made a summary of the development of numerical simulation and numericalsimulation software of groundwater at home and abroad. By collecting the hydrological andmeteorological data, geological and geomorphological data, hydrogeological data,groundwater monitoring data of the research area, the dynamic characteristics of groundwaterwas analyzed. According to the adoption of generalized hydrogeological conditions, thehydrogeological conceptual model of the study area was established. As a platform, theFEFLOW and GIS software technology were used to establish numerical simulation model ofthe groundwater flow. The main conclusions of the study contain:(1) Through analysis of the general characteristic of groundwater flow field, month andannual variation characteristic of changes and regional change characteristic of the study area,we know that the groundwater level is between367.69m and603.20m as a whole. In addition,the groundwater level in the northern part is higher than the counterpart in the south. Thegroundwater flows essentially from north to south and also to east and west. The groundwaterlevel dynamic change is distinct in different geomorphic units and regions, but the overalltrend is rising between February and March. More importantly, the peak can be found duringthis period. Then it drops to minimum within July and August. After that, the groundwaterlevel becomes to rise but is significantly lower than the drop increases. Annual change ofdynamic groundwater level also has the larger difference but the overall tendency increases atfirst, then decreases in the following. In general, the effect of natural factors of groundwaterdynamic changes is less. By contrast, human factor is the main influence factor for groundwater dynamic changes.(2) Based on hydrogeological conceptual model and GIS technology, FEFLOW softwarewas utilized to set up the corresponding numerical model. Through making adjustment formodel parameters, operation and identification, the accurate hydrogeological parameters aredetermined finally. The simulation result of the model is good. Specifically, the simulated andactual groundwater flow field has the same tendency basically. As for representative well ofsimulated and measured values, the average correlation coefficient is0.8293, average rootmean square of typical wells is0.5948m and the relative error is less than20%.(3) According to the socio-economic development and the12th Five-Year Plan ofXianyang City, water consumption, water supply capacity and water-saving potential of thestudy area, different scenarios of groundwater exploitation program were assumed and thepredicted groundwater source sink term was added as well into FEFLOW numerical modelwhich has been verified and identified to forecast the trend of groundwater level in2015. INprogram1,groundwater level decline1.32m;and in program2,groundwater level decline2.03m,thereby providing a certain reference for exploitation optimization and managementof groundwater in the study area.