Study On Groundwater Regulation Of The Bohu County Based On Ecological Security In Arid Area

Groundwater is an important resource in arid area, with the increase in Bohu Kaidu River Irrigation water demand, irrigation water use gradually changed. The lack of unified planning and management of water resources lead to excessive exploitation of groundwater, groundwater level dropped significantly,have a major threat to the ecological safety of Kaidu River and Bosten Lake Basin.Taking IrrigationArea oftheKaidu River in Bohu County as thestudyarea, through data analysis and calculation, the groundwater numerical model was established by means of Processing MODFLOW. Analysis and forecast scheme,put forward the suitable groundwater regulation scheme.(1) In view of the researchareapresent situation of groundwater level declining, analysis ofthe ecological environment elementsrelated to groundwater integratedly, in order to protect the ecological security as the foundation, proposed three groundwater regulation indices initially, namely,Suitable groundwater exploitation scale(GroundwaterWorkableReserve is 3766.4 × 104m3), ReasonableGroundwaterBuriedDepth2.5~4.5m, The Kaidu River water leakage 1537×104m3.(2)Status quo of groundwater budget calculation results show, Kaidu River water leakage and channel leakage, the two accounted for 78.8 percent of the total supply,in which the Kaidu River water leakage account for 38.5 percent of the total supply. Groundwater exploitation accounts for 67.5 percent of the total discharge,the main excretion items. Use Processing MOFLLOW to build three-dimensional numerical model of groundwater flow. With measured data to fit and validate the model, and the relative error is less than 5 percent.the model simulation results basically reflect the actual movement of groundwater, more credible.(3)Combined with the actual development characteristicsof the study area and the "three red line" water management indices, drafting three programs.Namely, present situation of groundwater exploitationprogram, the implementation of "three red lines" indices program, reducing the amount of groundwater exploitation programs on the basis of. the red indices. Scheme one,continue to 2014 groundwater exploitation conditions,to the end of 2030, the largest underground water level down to 13 m.Scheme two,to 2030 groundwater exploitation amount compared with the current year reduced 35.3 percent,groundwater level continued to decline trend eased,but there is still a large gap between the rational buried depth of groundwater, the amount of Kaidu River water leakage and the control index of groundwater. scheme three, thegroundwaterlevelrisestogreatextent in different degrees,by 2030 the maximum groundwater level drawdown reduced to 9m, the range is also reduced a lot,but the area of 2.5~4.5m drawdown is still less than 50 percent, less than 2m drawdown area of more than 30%, strengthenthe threat generated soil salinization, while Kaidu River leakage are still large, higher than the index of groundwater regulation 75.2 percent.(4)Suitable groundwater control scheme first to reduce the amount of groundwater exploitation,but also withcombined the adjustment wells exploitation layout, from the overall study area, Scattered groundwater extraction, reduce the range of the buried depth of less than 2m, from the overall regulate the groundwater drawdown in a reasonable range, and gradually restore groundwater recharge and drainage characteristics, thus reducing the amount of Kaidu River water leakage.