Rational Groundwater Exploitation Plan Based On Groudwater Level In Irrigation District

Groundwater level dynamic is the external expression of groundwater balance, it is also an important indicator of groundwater exploitation and utilization. So this research will use groundwater level as a way to develop a rational groundwater exploitation plan(RGEP) in a typical northern irrigation district in China. This research is very important to both realize the high efficient utilization of water resources in irrigation districts and the sustainable development of irrigation agriculture.By taking Jinghuiqu irrigation district as an example, this research will adopt both theoretical analysis and numerical simulation to develop a rational groundwater exploitation plan. GMS(Groundwater Modeling System) will be adopted considering its powerful andgreat features. The main conclusions are:(1)A groundwater system has been acquired based on groundwater cycle conditions, based on which the annual, monthly and spatial variation of groundwater table in unconfined aquifer was also obtained. The trend line of groundwater depth has two peaks, the minimum values are observed from March and April while the maximum values are August and September. The groundwater table has been declining in the last thirty years with a speed of 0.412m/year and 12.87 m in total. The ground water table is higher in the northwest corner than the southeast corner. The declining of groundwater table has seriously hindered the high efficient utilization of water resource.(2)A literature review on rational groundwater table in irrigation district has been finished, after which the maximum and minimum value of groundwater table in different hydrogeological area has been proposed.(3)Based on structures of the unconfined aquifer a concept model of hydrogeology in Jinghuiqu irrigation district has been developed, and a two dimensional transient groundwater model was constructed. GMS was adopted to develop a solid model and the model was also solved by mudflow module of GMS. After the calibration and verification the model has been well adjusted, so it could be used later in this research.(4) Based on the average irrigation water diversion and groundwater exploitation, four scenarios were developed by increase the irrigation water diversion by 5 to 10 percent while the groundwater exploitation decrease by the same amount or in a totally opposite way(decrease the irrigation water diversion by 5 to 10 percent while increase the groundwater exploitation by the same amount). By comparing the results from the model, a rational groundwater exploitation plan and a groundwater management plan were proposed.