Laboratory Simulation Of Solute Transport And Characteristics Of Freshwater-saltwater Interface In The Artificial Coastal Zones

With the industrialization and urbanization process accelerated, the landdevelopment intensity of coastal areas was expansive developing. In order to meet thedemands of land resources, the coastal cities set off a crazy wave of land reclamationfrom sea. the artificial coastal zones of land reclamation changed the natural beauty ofthe original natural coastlines, while changed the equilibrium state of seawater and thenear shore groundwater interactions, due to such human activities may reducedinshore groundwater level and formed seawater intrusion, and a large number ofindustrial activities on the land may formed potential pollutants of land-based sources.Groundwater and seawater interactions entered the offshore marine causing marineenvironmental pollution and other severe problems, therefore, study the dynamiccharacteristics of artificial shore fresh-saltwater interface by reclamation land, and themigration of interface solute have a great significance.The paper made a detailed test of the particle size, structure, composition,permeability by combined on-site sample testing with indoor supplementaryexperiment. Through analyzed above-mentioned variety of factors studied thecharacteristics and distribution laws of the dredger fill potential contaminants in thestudy area. After get the data of the geological and hydrogeological conditions of thestudy area, a certain proportion simulation the coastal groundwater system modeldevices were build in the laboratory based on the large sand tank model. The waterhead and the salt solution conductivity of the different sampling holes in verticaldirection were measured by changing the boundary conditions of the sea water head,and transformed the conductivity into the corresponding salt concentration, sodetermined the position of the freshwater-saltwater diffusion zones.When the indoor physical models and boundary conditions have beengeneralized, and the hydrogeological parameters and their source and sink termsconditions were get, the corresponding vertical two-dimensional coastal groundwaterflow equation and the convection-dispersion equation mathematical model were build,and numerical solving the mathematical model using the finite difference method.And the process used Visual MODFLOW software to achieve visualization. Themathematical model identification and verification by using experimental data of the water level and the concentration of solute in the process. Application of the model tosimulate freshwater interface on the migration of solute after determine a high degreeconsistent the simulation results with the experimental results. The coastalfreshwater-saltwater interface characteristics and the solute transport mathematicalmodel will provide important theoretical basis to reveal the interaction mechanisms ofthe regional artificial shore groundwater system and near coastal seawater, and will beestablish theoretical foundation to build the ecotype artificial coast.