Study On Impact Of Huaneng Tongchuan Power Plant On Groundwater Environment

Huaneng Tongchuan power plant, as one of the three dominant industry of Potou town,which located in the southwest of the planning area of Tongchuan, now is planning to startits second phase construction. According to related policy and laws, the impact of projectduring construction and operation on groundwater environment needs to be assessed. Thisresearch makes a thorough investigation of groundwater environment current situation instudy area on the base of previous research accomplishments and wild hydrogeology survey.The impact of Huaneng Tongchuan power plant on groundwater environment in thecondition of normal operation and accident was simulated and predicted by means ofestablished the groundwater flow and quality model. The main conclusions are as follows:(1) The unconfined aquifer in the study area is mainly occurred in eolian loess.Affected by terrain, the buried depth of aquifer increases from loess tableland center togully in both sides, meanwhile the aquifer thickness decreased. The phreatic water flowsfrom northwest to southeast, in the meantime flows from loess tableland center to the gully,discharged in Zhuoyu river and Zhao river, respectively.(2) The main recharge sources of groundwater in the study area are precipitationinfiltration and irrigation infiltration, which account for more than90%in total recharge.Other recharge sources include canal seepage and lateral seepage. The main discharge waysinclude artificial mining and gully runoff, which account for about72%in total discharge.Other discharge ways include lateral runoff and evaporation.(3) Monitoring results of groundwater environment shows a well water quality in studyarea. The high fluorine concentration is impressed by the fact that study area is located inhigh groundwater fluorine concentration area. Cluster analysis is used to analyze the impactof constructed first stage construction on groundwater environment, the results shows thatthe first stage construction hasn’t polluted nearby groundwater by far. Soil environmentmonitor shows a superior grade result in study area, which means the soil is free from heavymetal pollution.(4) Groundwater flow and quality model was established by Visual MODFLOW, and used to predict the impact of Huaneng Tongchuan power plant during operation ongroundwater environment, by chosen fluorine as predictor. In the prediction model,assuming contaminant infiltrate through the seepage control membrane with concentrationof1.5mg/L. Prediction results indicate that no over standard phenomenon appears aroundash yard and coal yard whether the background concentration is in average level or highestlevel. The simulation results showed no bad affection on groundwater of the villages nearcoal yard and ash yard.(5) Assuming contaminant fluorine infiltrate into aquifer with a concentration of1.5mg/L when seepage control membrane destructed or no seepage control ways.Simulation results show no fluorine over standard phenomenon in groundwater near coalyard and ash yard in the case of set background fluorine concentration with average level.When set background fluorine concentration with highest level, groundwater fluorine overstandard phenomenon appears in Lanjia ash yard with a range of0.0780km2. Thecircumstance of contaminant fluorine infiltrate into aquifer with a concentration of3mg/Lwhen seepage control membrane destructed or no seepage control ways was also simulated.Results shows no groundwater fluorine over standard phenomenon appears near coal yardand ash yard when the background fluorine concentration was set as average level. Whenthe background fluorine concentration was set as highest level, groundwater fluorine overstandard phenomenon appears near Lanjia ash yard, with a range of0.13km2. Simulationresults indicate that in accident conditions, coal yard and ash yard imposed less affection ongroundwater environment, won’t cause serious influence on groundwater as soon asmonitored and disposed timely.