Seawater Intrusion-Retreat Processes and Groundwater Evolution in Intruded Coastal Aquifers with Land Reclamation: A Case Study of Eastern Jiangsu, China
Key Laboratory of Surficial Geochemistry of Ministry of Education School of Earth Sciences and Engineering Nanjing University Nanjing 210023 China nju.edu.cn
Key Laboratory of Marine Sedimentology and Environmental Geology First Institute of Oceanography Ministry of Natural Resources Qingdao 266061 China mnr.gov.cn
Key Laboratory of Surficial Geochemistry of Ministry of Education School of Earth Sciences and Engineering Nanjing University Nanjing 210023 China nju.edu.cn
Tengfei Fu
Key Laboratory of Marine Sedimentology and Environmental Geology First Institute of Oceanography Ministry of Natural Resources Qingdao 266061 China mnr.gov.cn
School of Earth Sciences and Engineering Hohai University Nanjing 210098 China hhu.edu.cn
Xingyong Xu
Key Laboratory of Marine Sedimentology and Environmental Geology First Institute of Oceanography Ministry of Natural Resources Qingdao 266061 China mnr.gov.cn
Xiaobin Zhu
Key Laboratory of Surficial Geochemistry of Ministry of Education School of Earth Sciences and Engineering Nanjing University Nanjing 210023 China nju.edu.cn
Hongjun Yu
Key Laboratory of Marine Sedimentology and Environmental Geology First Institute of Oceanography Ministry of Natural Resources Qingdao 266061 China mnr.gov.cn
Shengfa Liu
Key Laboratory of Marine Sedimentology and Environmental Geology First Institute of Oceanography Ministry of Natural Resources Qingdao 266061 China mnr.gov.cn
Maosheng Gao
Qingdao Institute of Marine Geology CGS Qingdao 266071 China grid.ac
Guohua Hou
Qingdao Institute of Marine Geology CGS Qingdao 266071 China grid.ac
AbstractThe hydrogeochemical analysis and numerical simulation were conducted to explore the impact of land reclamation on submarine groundwater discharge and groundwater evolution in the seawater intrusion-retreat processes in eastern Jiangsu, China. The hydrogeochemical results indicated that the origin of salt in most groundwater is saltwater mixing, and weathering-dissolution of minerals enriches the salt in fresh groundwater. The evolution path of coastal groundwater in Jiangsu is Ca-Na-HCO3-Cl → Ca-Na-Cl-HCO3 → Na-Ca-Cl-HCO3 → Na-Mg-HCO3 → Na-Mg-HCO3-Cl → Na-Cl-HCO3 → Na-Cl, and the difference in groundwater evolution in different regions is obvious. The numerical simulation revealed that the land reclamation has blocked groundwater exchange and restrained the seawater intrusion. The sensitive analysis indicated that the permeability and the slope of the land reclamation have dominated the salinity distribution. And the aquifer heterogeneity promotes groundwater evolution and leads to the irregular salinity distribution of the groundwater. Moreover, the groundwater evolution in the shallow aquifer with the land reclamation shows that the residual seawater is gradually desalinating and discharged into the sea. The land reclamation is salinized by saltwater discharge and seawater intrusion together and then subsides into a stable saltwater wedge. The groundwater salinity distribution in Jiangsu is not fit seawater intrusion, which is caused by the coastline changes due to anthropogenic land reclamation and natural activities.
