Hydraulic Capture Optimization and Risk Assessment of Polluted Groundwater Based on Kriging Surrogate Model

Building a hydraulic capture system through simulation–optimization methods has become an effective measure to control and eliminate groundwater pollution. However, there is a problem of large calculation load in the process of solving the simulation–optimization models, and the uncertainty of hydrogeological parameters is often not considered in the constructed models, which leads to some risks in the constructed hydraulic capture system. This paper proposed to use the hydraulic head differences at the boundary line of the pollution plume to constrain the groundwater flow direction to achieve pollutant capture, and proposed a hydraulic capture optimization system for the polluted groundwater based on the Kriging surrogate model. What is more, the hydraulic conductivity’s uncertainty was introduced into the simulation–optimization model, and a stochastic simulation–optimization model was constructed to evaluate the risk of the optimal scheme. The results of the case study showed that the Kriging surrogate model based on the optimal Latin hypercube sampling method can achieve a better replacement of the simulation model. Taking the hydraulic head differences at the boundary line of the pollution plume as a constraint can effectively control the groundwater flow direction. The optimal hydraulic capture system derived from the simulation–optimization model was two pumping wells, mainly concentrated downstream of the central axis of the pollution plume, and the scope of the capture zone was larger than that of the pollution plume. With the hydraulic conductivity following a log-normal distribution within the site, the optimal hydraulic capture scheme has a high-risk rate of 30.55%.