Analytical Solution Of Groundwater Submarine Discharge Through Horizontal Fracture Aquifer

Slubmarine groundwater discharge(SGD)is recognized as a major pathway of groundwater to coastal ocean environments.It could affect water quality and marine ecosystems due to pollu-tants and trace elements transport..Although hydrogeologists have investigated relations between different characteristics of aquifers and SGD,the role of fracture in SGD still remained unknown.To better understand the mechanism of groundwater propagation through fractures in SGD,one-dimensional analytical solutions of hydraulic head and velocity of groundwater through a synthetic horizontal fraeture was derived using the Laplace transform technique.Then a.numerical solution of solute transport associated with groundwater through the fracture was derived using a char-acteristic difference method.The results indicated that the groundwater propagation and solute transport associated SGD were mainly controlled by sea level periodic fluctuation,which altered the hydraulic head and the hydraulic head gradient in the fracture.As a result,the velocity of groundwater in the SGD fluctuated periodically.Consequently,through advection and dispersion,the pollutant concentration in the SGD oscillated around a constant concentration value,and could not reach a steady state,in particular,close to the seashore.This finding of the role of fracture in SGD will assist pollation remediation and marine conseniation in coastal regions.