| Peninsula is an important channel of material transmission,energy transfer and information exchange between land and sea.Its environmental changes have a profound impact on the surrounding regions.Reclamation is a common way to alleviate human-land conflict.There are some oil spills in coastal areas in recent years,which is a serious hazard to the surrounding environment,especially groundwater resources on island.As one of national development zones and a special cross-strait exchange window,Gulei Peninsula has many petrochemical factories.Therefore,it is necessary to research the potential impacts of different reclamation materials and reclamation mode on regional groundwater and pollutant transport,as well as the appropriate groundwater pollution control measuresTaking Gulei Peninsula as the research object,this paper systematically analyzed hydrogeological conditions,used Groundwater Modeling System(GMS)to build the three dimensional groundwater flow model,and simulated groundwater flow field and pollutant transport in two reclamation sceneries,including sand-filling reclamation(scenario 1)and sand-clay-filling reclamation(scenario 2).Last but not least,the effect of pumping capacity on groundwater pollutants was predicted by conducting pump and treat technology based on scenario 1.The results are as follows:(1)Gulei Peninsula is mainly distributed with loose rock pore water and weathering zone pore fissure water.The climatic condition is the main factor affecting the fluctuation of groundwater level.Precipitation infiltrates into the aquifer,then flows from the north and south sides to the middle of the peninsula.And north-south ridge watershed forms in the peninsula axis.Lastly,groundwater flows into both sides of the east and the west,respectively Precipitation and inflow runoff are the main recharge,and evaporation and outflow runoff are the main discharge.(2)The reclamation of the west side in Gulei Peninsula will increase the groundwater recharge in reclamation area,but the basic direction and patterns of terrestrial groundwater flow had no significant change after reclamation.There was a regional increase of water table,which scenario 2 is stronger than that of the scenario 1.(3)Without considering the chemical and biological conditions of soil contaminants,the main factors of pollutant migration were reclamation material,stratigraphic lithology and reclaimed groundwater flow field.Contaminant transport of scenario 1 was significantly faster than that in scenario 2,but contaminant concentration was lower than the latter.(4)Under the background of pollution accident with the leak-off time of 90 days in scenario 1,the pollutant removal of 6 pumping wells,located at 50 m downstream of the leak and perpendicular to the groundwater flow,with a single well pumping capacity of 400m3/d is highest within 5 years.(5)Comprehensive consideration based on pollution prevention and control,reclamation materials and emergency treatment costs,it is suggested that reclamation in scenario 2 should be recommend.Under the pollution condition of scenario l,the optimal solution to emergency treatment of the groundwater pollution is 6 pumping wells with a single well pumping capacity of 400m3/d and perpendicular to the groundwater flow.(6)To enhance the credibility of the model and prevent groundwater pollution,it is suggested to build the groundwater monitoring network consist of 86 water level monitoring wells with monitoring frequency of 3 times per year and 3 water quality monitoring wells with monitoring frequency of once in a quarter in Gulei Peninsula.The factory to be built can visualize the chemical raw material tank area,carry out Anti-seepage standard of key pollution prevention and control area,and formulate detailed emergency treatment plan. |
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