Prection And Regulation Of Salinity In Estuarine Reservoirs

The international and domestic practices show that the construction of Estuarine Reservoir in coastal cities can effectively alleviate the shortage of local water resources.However,Estuarine Reservoirs are generally built in the bays where rivers enter the sea.The pore water in Estuarine Reservoirs is salty water with high salinity.After the impoundment of the reservoirs,the salt in the pore water diffuses into the reservoir water.So that the reservoir water is threatened by salinization.Therefore,the research of the measures to prevent salinity could be guidance for the construction of the Estuarine Reservoir and its operation after constructed.Laboratory soil column experiments and laboratory flume experiments were carried out.The experimental results show that:(1)Pumping out the intersititial water can effectively mitigate the salinization of the Estuarine Reservoirs.And the more pore water was released from the sediment,the greater the effect.(2)Draining out the initial impounding can effectively reduce the salinity of the water in reservoir.The measure can inhibitory the abrupt salinization of reservoir water.(3)Compared with the draining out the initial impounding,the "comprehensive" measures to prevent salinity,which are combined with pumping intersititial water and draining out the initial impounding,can effectively mitigate the salinization of reservoir water and restraining the abrupt salinization of the reservoir.(4)During the operation of Estuarine Reservoir,pumping out the salt water in bottom boundary layer can effectively reduce the overall salt concentration of the reservoir water and reduce the thickness of the bottom boundary layer.The timing to pumping out the salt water in bottom boundary layer is particularly important.AQUASIM software was used to perform one-dimensional modeling.The temporal and spatial distribution of salinity in reservoir water under different conditions was simulated to further confirm the effectiveness and necessity of measures to prevent salinity.Comparing the simulation results of different water inflow and outflow conditions,it was found that the salinity taken by the daily water supply in the Mugudao Reservoir did not have a significant impact on the salinization of the reservoir water without considering the change of the water level(mainly the water level drop process).The disturbance caused by strong wind is one of the important reasons for the abrupt mixing of meromictie reservoirs.On the basis of the quantitative relationship between the Wedderburn number and the vertical displacement scale of the bottom boundary layer,this paper predict the critical wind speed for abrupt mixing in Muguandao estuarine reservoir combined with the topography and layered location of the Muguandao reservoir.Offering the conclusion that:(1)Reducing the thickness of the bottom boundary layer of the reservoir could effectively reduce the probability of abrupt salinization of the estuarine reservoir water.(2)According to the real-time statistics of salt concentration and temperature in the upper and lower layers of the Estuarine Reservoir,determine the location of the stratification,and then calculate the critical wind speed of the abrupt mixing of the Estuarine Reservoir.Pumping out the bottom salty water until the wind speed forecasted reaches the critical speed value of abrupt mixing can increase the utilization rate of funds.