Numerical Simulation Of Groundwater Movement In The Yellow River Delta Wetland Ecosystem

Both the biological resources and the scenic resources are extremely rich in the Yellow River delta wetland, which have the significant scientific research value and the ecology significance. At Present, the ecological environment of the Yellow River delta wetland becomes worsen and worsen, the wetland area decreases continually, the quality drops and the ecology service function of the wetland degenerates obviously, influenced by both the human factor and the natural factor such as the increasing population, the development of industry and agriculture and so on.In this dissertation, the numerical simulation method was used to establish the shallow layer groundwater movement model in the Yellow River delta wetland thereby forecasting subsoil water level changing tendency in all kinds of conditions in the future and analyzes the effects on the Yellow River delta wetland ecosystem, which can provide the basic information for the reasonable development use and the scientific management of the Yellow River delta wetland. Before the numerical simulation, we carried on the hydrologic geological prospecting work to the Yellow River delta wetland, then established the shallow layer groundwater movement conceptual model in order to make a mathematical model which could represent this local groundwater movement. We used the Modflow module in GMS for the solution of the mathematical model. After the recognition and the confirmation, we established the water quality model of research area and carried on the model forecast.The research area of mathematical model which we made was border and the influencing factors which we considered were more comprehensive than others. After the adjustment and the confirmation, the error of computation conformed to the national standards, therefore this model could reflect the movement characteristic of the groundwater system. We could divide hydrologic geological parameter of the research area into 10 areas after the recognition of parameter. The water quantity of the research area achieved balance when we computed, in which the precipitation and the evaporation were main sources in the groundwater system.In view of the groundwater quality characteristic in the Yellow River delta wetland, MT3D was used to establish the migration model of the chloride ion, we also simulated the chloride ion changing tendency. The result indicated the density of the chloride ion was increasingly high both in the spatial change from the interior to the seashore and along with the time passing in the research area. The main causes of the situation above were the invasion of the seawater and the evaporation.We had made a 5-year long-term forecast through the model firstly, after then we forecasted the influence of the Yellow River water volume change and the precipitation change as well as the storm tide to the groundwater in the research area. In the hydrologic changes, it was obviously that continuous block of the Yellow River and the storm tide influenced heavily to the groundwater level, which could destroy the ecological environment of the Yellow River delta wetland. In the same hydrologic change, the increasing of the precipitation could reduce the density of the chloride ion, the storm tide could increase the density of the chloride ion along the coast. Finally, we proposed the corresponding measure according to the possible factors which could destroy the ecosystem of the Yellow River delta wetland.