Effect of Reclamation on the Groundwater-Lake Water Interaction in Chen Lake

Chen Lake has been seriously modified by reclamation to expand the residential and agricultural area. Lake reclamation can decrease water quantity, cause water quality problems, and degrade water ecological function. To clarify the interaction between groundwater and lake water influenced by reclamation, water level and hydrochemical characteristics of five groundwater nests and three lake sites were monitored. Results emphasize that the seasonal fluctuations of lake water level is an important factor for both recharge and maintaining groundwater levels in study area. Groundwater in reclaimed farmland have seasonal patterns following lake water with a lag time. Noteworthy, the lag time of porewater in reclaimed farmland is one month longer than confined water. HCA showed that lake water and groundwater samples in same cluster were characterized by high δD, δ18O, Cl- and K+, suggesting the provision of lake to groundwater systems and the transfer of chemical signature. Other Cluster was dominated by reclaimed farmland groundwater samples and enriched in Ca2+, HCO3-, Si. This finding interpreting that water-rock interaction is the predominant process in reclaimed farmland. As a result, there is a high degree of connectivity between lake water and underlying groundwater. However, porewater hydrodynamic conditions gradually weaken and groundwater recharge in reclaimed farmland is modified after large-scale reclamation.