An analysis of the stress effects and methods of the shallow groundwater quality in the Hutuo River alluvial fan

Taking the Hutuo River alluvial fan as an example, this study uses the inferior and deterioration water evaluation method, based on the groundwater background values, to differentiate the type of external stress effect on groundwater and to divide the distribution range of different types of water. The reliability of the evaluation results is verified by human activities. The evaluation results show that the first grade deteriorated water area accounts for 65.9% of the total area, and the second grade water area accounts for 15.7%, which indicates that the groundwater quality of most areas in the study area tends to deteriorate under the influence of human activities. In order to further summarize the specific stress modes of groundwater quality, the main factors extraction are carried out in the factor analysis. The results show that the main stress of the first grade deteriorated water is the change in hydrogeochemical field due to ground water over-exploitation, which caussd an overall increase in salt content in groundwater. The second grade deteriorated water is mainly affected by the input of pollutants such as domestic and industrial wastewater, farms and landfill leachate. In addition, ion is the natural inferior component in the study area, which is affected by the natural factors such as lithology and hydrogeological conditions, and its concentration exceeds the upper limit of the background value in some areas under the influence of human activities, and further deterioration has occurred.