Analysis On Control Countermeasures Of Seawater Intrusion In The Beachfront Of Haihe River Basin

ABSTRACT Seawater intrusion is one of natural hazards not to be ignored in the coast zone.The high salt degree seawater invade and permeate the inland along some coast areasand river, as a result, the groundwater quality and the degree of soil secondary salinityis deteriorated. The emergence and development of seawater intrusion cause negativeeffect on the environment and economy of beachfront. The influence of seawaterintrusion on the ecological environment and human life is discussed in detail in thispaper. Some conclusions with regularity are summarized after analysis on thesituation of beachfront in Shandong province. The current situation and origin ofseawater intrusion is investigated in the coastal area of Yellow Sea and Bohai Sea.The occurrence and development trend of seawater intrusion is presented due to theinfluence of natural factors and human factors. Groundwater quality monitoring is an important mean to estimate seawaterintrusion. The contaminated degree of coastal aquifers in a specific area is a " fuzzy "issue. Considering the characteristic of seawater intrusion, a comprehensive fuzzymathematics model is deduced to evaluate seawater intrusion by applying the Fuzzytheory. Based on the principle of subordinate degree, the ranking of intrusion degreeis obtained. This mathematics model is carried on in the beachfront of Laizhou Gulfto estimate the degree of seawater intrusion successfully. The mechanism and dynamical reasons of seawater intrusion are studied. Thehorizontal width and obliquity of intermediate zone is obtained by mathematicsdeducing. Coupling with the flow equation and advection-dispersion equation, anumerical model for density-dependent groundwater is developed and solved withGalerkin finite element method. Finally, Henry model and the solute transport of saltwater in riverway are simulated by this numerical model. In order to prevent the beachfront in Haihe River Basin from seawater intrusion,management countermeasures are discussed in details, and the theories of somecountermeasures are emphatically analyzed in this paper. Considering the feasibilityof recharging groundwater by utilizing flood and urban wastewater in Haihe RiverBasin, some methods and theories of recharging freshwater in preventing seawaterintrusion are investigated. The fundamental conception of flood resources is givensummarily,and an idea is proposed to prevent and cure seawater intrusion byimposing flood on recruiting groundwater and irrigation.