Evaluation Of Groundwater Vulnerability In Songyuan Qianfu Oilfield Development Zone

The Qianfu oil-field area of Songyuan city, Jilin province, is a newly economy development area, where the petroleum industry has been taken as one of the main industry. And the groundwater is an important water resource for the local industrial and agricultural development and living. In the oil-field developing processes, the groundwater has played an extremely important function. In recent years, as a result of the mine of petroleum resources and the extensive exploitation of the groundwater resources, the groundwater pollution and water quality deterioration have led to many environmental problems. So, it is of momentous significance to studying the groundwater vulnerability of the oil-field area currentlly, that will provide some scientific evidence for rational utilization and protection of groundwater.Owing to this, based on the investigation of natural geography, geologic and hydro geological conditions in this area, this paper analyzed the mechanism of groundwater vulnerability. According to the analysis of influencing factors on inherent vulnerability, the assessment index system of inherent vulnerability of groundwater has been established. Moreover, we used the DRASTIC Index method and the Fuzzy Comprehensive Evaluation method to synthetically assess the groundwater inherent vulnerability, combining with the GIS technique. In evaluation systems with Fuzzy Set theory, the weights of the assembled factors are determined by using the AHP method. At last, by means of the MAPGIS software, this paper mapped the inherent vulnerability maps of the Qianfu oil-field area.The studying result indicates that the groundwater vulnerability assessment results using the above two methods are nearly consistent. Simultaneously, it verifies the rationality of groundwater vulnerability regions. The groundwater vulnerability class of the most regions in the Qianfu oil-field area belong to the medium vulnerable area and the higher vulnerable area, and the lower vulnerable area is little.The causes for the assessment results of the groundwater vulnerability, and the relationship between the groundwater vulnerability and the groundwater pollution degree, has also been analyzed systematically. Moreover, for the groundwater vulnerability assessment carrying out in this paper belong to the groundwater inherent vulnerability, which has not considered the influence of special factors such as human activities and so on. The assessment results of the groundwater vulnerability is not according with the actual groundwater pollution condition absolutely, even the groundwater of some lower vulnerable area evaluated has been polluted severely. So, the polluting situation should also be taken as an important indexe for the groundwater vulnerability assessment.