Effects of Tidally Varying Salinity on Groundwater Flow and Solute Transport: Insights From Modelling an Idealized Creek Marsh Aquifer

Xiao, Kai1,2; Li, Hailong1; Xia, Yuqiang3; Yang, Jinzhong2; Wilson, Alicia M.4; Michael, Holly A.5; Geng, Xiaolong5; Smith, Erik6; Boufadel, Michel C.7; Yuan, Ping1; Wang, Xuejing1

2019-11-23

10.1029/2018WR024671

WATER RESOURCES RESEARCH   影响因子和分区

0043-1397

1944-7973

Most existing numerical research on tide-induced groundwater dynamics assumes a constant surface water salinity on the seaward boundary (constant salinity case). Few studies have investigated the influence of tidally varying salinity on shallow groundwater dynamics in coastal aquifers (tidal salinity case). We compiled field observations of tidally varying salinity in multiple estuaries across the eastern coast of China and a tidal creek in North Inlet-Winyah Bay, United States. Numerical simulations were then conducted to explore the effect of tidally varying salinity on groundwater flow and salt transport in an idealized creek marsh aquifer. Results showed that the upper saline plume and classical saltwater wedge appeared in all cases, but the salinity in the saltwater wedge was diluted in the tidal salinity cases. Notably, groundwater transit times were shorter in the tidal salinity case than in the constant salinity case, especially under the creek bottom. Quantitative analyses indicated that tidally varying salinity significantly enhanced surface water-groundwater exchange, increasing submarine groundwater discharge by 10% and the total inflow of surface water across the water-sediment interface by 7%. As the density of groundwater differs from that of the overlying surface water, fingered saltwater flow formed in sediments under the creek bottom, leading to some small local water circulation cells. These small cells reduced groundwater transit times and almost doubled the water exchange rate. Coupling the density-dependent flow to a simplified nitrogen reaction network revealed that the tidally varying salinity may have the potential to influence nitrogen biogeochemical transformations that modify nitrogen loads prior to discharge.

submarine groundwater discharge numerical simulation tidal creek upper saline plumes coastal wetlands

SCI ; EI

英语

第一 ; 通讯

National Basic Research Program of China ("973" Program)[2015CB452902]

Environmental Sciences & Ecology ; Marine & Freshwater Biology ; Water Resources

Environmental Sciences ; Limnology ; Water Resources

WOS:000501338300001

AMER GEOPHYSICAL UNION

20194807746470

Aquifers ; Computer simulation ; Discharge (fluid mechanics) ; Groundwater flow ; Groundwater resources ; Hydrogeology ; Nitrogen ; Numerical models ; Solute transport ; Submarines ; Wetlands

Surface Water:444.1 ; Groundwater:444.2 ; Geology:481.1 ; Combat Naval Vessels:672.1 ; Computer Applications:723.5 ; Chemical Products Generally:804 ; Mathematics:921 ; Classical Physics; Quantum Theory; Relativity:931

ENVIRONMENT/ECOLOGY

Web of Science

1.Southern Univ Sci & Technol, Sch Environm Sci & Engn, Guangdong Prov Key Lab Soil & Groundwater Pollut, Shenzhen, Guangdong, Peoples R China
2.Wuhan Univ, Sch Water Resources & Hydropower Engn, Wuhan, Hubei, Peoples R China
3.Minist Water Resources, Changjiang Water Resources Commiss, Changjiang River Sci Res Inst, Wuhan, Hubei, Peoples R China
4.Univ South Carolina, Sch Earth Ocean & Environm, Columbia, SC 29208 USA
5.Univ Delaware, Dept Geol Sci, Newark, DE USA
6.North Inlet Winyah Bay Natl Estuarine Res Reserve, Georgetown, SC USA
7.New Jersey Inst Technol, Dept Civil & Environm Engn, Ctr Nat Resources Dev & Protect, Newark, NJ USA

Xiao, Kai,Li, Hailong,Xia, Yuqiang,et al. Effects of Tidally Varying Salinity on Groundwater Flow and Solute Transport: Insights From Modelling an Idealized Creek Marsh Aquifer[J]. WATER RESOURCES RESEARCH,2019,55(11):9656-9672.

Xiao, Kai.,Li, Hailong.,Xia, Yuqiang.,Yang, Jinzhong.,Wilson, Alicia M..,...&Wang, Xuejing.(2019).Effects of Tidally Varying Salinity on Groundwater Flow and Solute Transport: Insights From Modelling an Idealized Creek Marsh Aquifer.WATER RESOURCES RESEARCH,55(11),9656-9672.

Xiao, Kai,et al."Effects of Tidally Varying Salinity on Groundwater Flow and Solute Transport: Insights From Modelling an Idealized Creek Marsh Aquifer".WATER RESOURCES RESEARCH 55.11(2019):9656-9672.