Presenter: Dr. Hang Zhao
Co-author(s): Dr. Guoxin Huang, Dr. Jian Chen
Organisation: Chinese Academy of Environmental Planning
Sub-theme
4. Supporting Aquatic Ecosystem Health and Functions
Topic
4-8. Water quality improvement
Body
Groundwater is the main source of drinking water in northern China. Environmental risks around pumping wells can be effectively prevented through the delineation and management of drinking groundwater source protection zones. Whereas understanding and assessing the impact of pollution sources on the water source within the recharge zone (mostly larger than the protection zone) is critical to make drinking water management decisions. In this case study, hydrogeological analysis and particle tracking method were combined to delineate the recharge zone of a representative groundwater source in Yellow River Basin firstly. Random forest method was implemented to quantitatively identify the contribution of primary pollution sources within the recharge zone. Multiple spatial environment factors were taken as predictor variables. MODFLOW and MT3DMS numerical models were utilized to simulate the groundwater flow and solute transport process and evaluate the influence of major pollution sources on groundwater system. The main influencing factors were recognized based on the simulation results of different scenarios. Countermeasures for water source risk prevention were proposed according to analyzing the relationship between source and sink in three dimensions. The results show that (1) The consequence obtained from applying of random forest indicates that the contribution of industrial pollution source is higher than other sources in the groundwater recharge zone; (2) The influence of industrial pollution on water sources is affected by the migration of contaminants, anti-seepage conditions, and permeability of aquifer, especially the distribution of local low-permeability interlayer; (3) The demarcation and management of groundwater source recharge zone is the premise of ensuring water source security. Combining the prevention of surface industrial pollution sources and groundwater monitoring within the recharge zone is an alternative sustainable strategy of recharge zone protection. The results presented in this study will be beneficial for the long-term safety and effective quality improvement of drinking groundwater sources.