Search Results (2)

The appropriate division of underground drinking water source protection zones is a low-cost method of preventing water source pollution and ensuring a supply of safe drinking water. Based on FEFLOW, a groundwater flow model of large water sources was established for Luan River, North China. Trace lines of particle reverse migration for 100 and 1000 days were obtained by random walks. According to the trace morphology, the water sources in the riverside water source area were divided into four categories. The first- and second-grade protection areas were delimited by ArcGIS, with areas of 0.375 and 1.20 km². The local and global sensitivity of the permeability coefficient (K) and effective porosity (n_e) effects on the area of groundwater protection zones were calculated. The area of the protection zones was positively correlated with K and negatively correlated with n_e. The variation in the protected zone caused by the simultaneous changes in K and n_e is the same as that of n_e alone, and the global sensitivity is closer to the local sensitivity of n_e. This indicates that n_e has a greater impact than K on the scope of groundwater protection zones. Moreover, global sensitivity is not simply a superposition of local sensitivity, and the interaction between parameters can reduce the effect of a parameter acting alone on the delineation of protection zones. This also shows that the global sensitivity is closer to the actual situation than the local sensitivity, thus providing a scientific basis for the delimitation and monitoring of water source protection zones. Full article

Groundwater quality in the Muling–Xingkai Plain (MXP) is closely related to food security and human health. The chemical composition of groundwater in MXP has attracted great attention. A total of 168 groundwater samples were collected in MXP, and principal component analysis, chemical ion analysis and stable isotopic analysis were used to explore key factors affecting the chemical composition and hydrochemical evolution process of groundwater. Results show sources of chemical ions in groundwater are silicate minerals, carbonate minerals and domestic sewage. Domestic sewage is responsible for groundwater with high levels of Cl⁻, SO₄²⁻ and NO₃⁻, but a reduction environment can lead to groundwater with a high level of NH₄⁺ due to nitrification. Human activity and soil media together influence groundwater chemical composition. Groundwater with a high level of chemical ions is mainly collected from wells near river channels, where coarse-textured soils are overlying aquifers. The black soil far away from river channels can retard the infiltration of wastewater. Agricultural activities do not directly lead to deterioration of groundwater qualities, and agricultural non-point-source pollution does not occur in MXP. Nearly 70% of the population in MXP is living in the southern plain, where the influence of sewage on groundwater chemical composition is obvious. Thus, shallow groundwater far away from river channels is the best choice for irrigation. Some measures should be implemented to control the discharge of domestic sewage for the protection of groundwater. In addition, it is necessary to avoid the transformation of the redox environment of groundwater in the northern plain. Full article