The Simulation Forecasting And Study On The Management Model Of Groundwater In The Western Jilin Province

Groundwater as a resource, is not inexhaustible. as the rapid development of the industrial and agricultural and the people's living standards, the requirement of groundwater resource has risen rapidly in the whole society, particularly in the urban areas which take groundwater as the main sources of water supply, and the excessive extraction of underground water has led to a series of problems of environment geology, such as sustained decline of regional groundwater level, deterioration of groundwater quality, depletion of groundwater resources, Land subsidence and other environmental problems. Therefore, the scientific management of groundwater resources has become imperative. For the western of Jilin area with a semi-arid and semi-humid mainland monsoon climate,and transition zones between humid eastern monsoon and arid inland area, it is lack of water resources, with the increase of groundwater resources utilization year by year, and resulting land salinization, desertification and grassland degradation, soil erosion and other problems. Therefore, it has great significance in ecological construction and economic development to carrying out research in groundwater resources management and determining optimal mining scheme.This paper first reviewed the research trend of numerical simulation of groundwater and the domestic and abroad study progress on groundwater management model.Secondly, with the study area hydrogeology conditions, identifing the composition of the aquifer system, elucidating the dynamic characteristics of groundwater recharge, runoff, discharge in the study area,establishing the hydrogeological conceptual model. In the study area,vertically can be divided into four groups: shallow unconfined aquifer group, aquitard, middle-deep confined aquifer group, they have unified hydraulic connections, which constitute a unified three-dimensional flow system. At the same time, in the vertical and lateral borders , the study area is generalized treatmentSelecting the popular software MODFLOW to solve the simulate system of groundwater. During recognition period (January 1, 2001 to April 1, 2001, for a total of 90 days), in the first period, the average absolute error of phreatic observation well water level is 0.298 m, the observation well which fitting error is less than 0.5 m take account for 88.49% of the total observation wells,in the second period, the average absolute error is 0.327 m, the observation well which fitting error is less than 0.5 m take account for 91.36% of the total observation wells. During test period (July 1, 2004 to October 1, 2004, a total of 92 days), the average absolute error of the fitting of phreatic observation well water level is 0.344 m, the observation well which fitting error is less than 0.5 m take account for 94.57% of the total observation wells. the average absolute error of the fitting of confined observation well water level is 0.378 m, the observation well which fitting error is less than 0.5 m take account for 86.61% of the total observation wells.Using historical recurrence method to predict the precipitation and evaporation during the planning period from 2005 to 2009.the prediction of seepage irrigation is according with the amount of water used in agriculture and local agricultural development planning. Prediction of groundwater yield:From 2004 to 2008,the quantity of groundwater exploitation increase by the rate of 8.71 percent, and remain unchanged in 2009 .Taking predicting modle as background,serving the western of Jilin as study area,on the base of the comprehensive analysis of key research areas development planning, on condition that establishing the management objectives, groundwater level, water demand and other constraints, and then established the groundwater water management model which take largest mining as the objective function, through the solving of software LINGO, identifing the maximal source of water for the exploitation in 2008 is 296.573×105m3/a , 328.435×105m3 /a in 2009, At the same time, giving the optimal mining plan in the management area ,and serving as a reference to the region economic development program.