Hydraulic interaction between groundwater and surface-water at Zengpiyan site in Guilin, China

Zengpiyan is located in the Guilin Peak forest plain. The stability of this site is threatened by groundwater scouring due to the change of hydrodynamic conditions of karst groundwater. In order to examine the characteristics of groundwater leakage process, and to reveal the transformation process of groundwater and surface water in the protected areas of the site, this study analyzed the dynamic characteristics of water level. The tank model and water level decay equation were constructed according to the water balance elements of karst water system. Then the difference between the simulated water level and the actual water level was compared to explain the relationships between rainfall, surface water and groundwater. The results show that there are various differences between the pond and the groundwater, such as the water level, the start rising point, the decay rate and the lag time of the peak. The difference in dynamic processes reflects the strong communication capacity of karst media. The leakage process of the pond is controlled by seepage capacity. Groundwater recharging to surface water reservoirs is dominated by concentrating supplies through main runoff zones. The hydraulic interaction between groundwater and surface water shows strong dynamic patterns, especially in the high-permeability karst areas. The hydraulic interaction of groundwater and surface water is beneficial to alleviate the erosion and damage of groundwater to the cover layer.