Study On The GIS Based Irrigation District Groundwater Resources Evaluation System

The exploitation and utilization of groundwater resources provides high quality and reliable water source for irrigation district and promotes sustainable development of irrigation district. But because of the deficiency of scientific reasonable planning and effective supervision in some irrigation district, there have been some groundwater problems in some area, such as groundwater level decreased greatly and groundwater pollution, which has affected the development of irrigation district. However, it is a pity that groundwater resources evaluation in irrigation district has not yet received enough attention at present, which causes the deficiency of powerful scientific guiding in rational exploitation and utilization of groundwater resources in irrigation district.With the development of computer technology, the development of groundwater resources evaluation has become increasingly information-oriented. This paper analyzed the necessity and the feasibility of the integration of GIS technology and groundwater resources evaluation in irrigation district thoroughly and constructed spatial database of groundwater resources evaluation, studied the application of GIS technology in the acquisition of hydrogeology parameters, the computation of groundwater equilibrium elements, the analysis on groundwater equilibrium, the groundwater quality evaluation and the evaluation of groundwater utilization potentiality, then take Baojixia irrigation district as an example, developed the irrigation district groundwater resources evaluation system which is based on VB and SuperMap Objects and carried on groundwater resources evaluation in Baojixia irrigation district.The results showed that as a burgeoning high and new technology, GIS technology has overriding advantages in spatial information processing, the integration of GIS technology and groundwater resources evaluation in irrigation district could realize the visualized groundwater resources evaluation and reflect the spatial variation of quantity and quality of groundwater in irrigation district objectively. The Spatial database of irrigation district groundwater resources evaluation could provide strong and overwhelming support for GIS based irrigation district groundwater resources evaluation, the spatial database is the prerequisite of GIS based irrigation district groundwater resources evaluation at the same time. By means of GIS technology and the spatial database of irrigation district groundwater resources evaluation, acquired correlative hydrogeology parameters and realized the spatial spreading and visualization of the computation of groundwater equilibrium elements. Developed GIS based irrigation district groundwater resources evaluation system, which is capable of quantity evaluation of groundwater resources, quality evaluation of groundwater resources and the evaluation of groundwater utilization potentiality and fully supply the demand of irrigation district groundwater resources evaluation. The results of Baojixia irrigation district groundwater resources evaluation show that allowable groundwater withdrawal quantity in normal rainfall year is 267 million m3, in low rainfall year it is 234 million m3, in extremely low rainfall year it is 207 million m3. In 2002, groundwater quality is good enough for farmland irrigation water and source of water supply. In the northern part of Wugong country, southern part of Qian country, southern part of Xingping city, there is a balance of exploitation and supplement of groundwater resources. In the southern part of Liquan country, central part of Xingping city and southern part of Xianyang city, the exploitation quantity of groundwater resources is much bigger than supply amount. In the result part of the Baojixia irrigation district, the exploitation quantity of groundwater resources is less than supply amount.