Estuary Bay Reservoir Sediment The Salt Release Of Water Salinization And Its Prevention And Control Measures

Water resources insufficiency has become an main constraints to social and economic development in our country, especially in coastal areas. The construction of polder reservoirs which can accumulate river water flowing into the sea is an important way to alleviate the water shortage in coastal areas. But after the completion of a polder reservoir, the impoundment salinity and the whole overlying water' seasonal mixing or meromixing will affect water quality and normal function of the reservoir, according to the data of original source, tidal deposits rich in high-salinity interstitial water at the reservoir bottom is the major causes. Therefore, the study on influence factors of endogenous salt migration and predict the migration trends of the endogenous salt in sediment, has significance in theory and practice.We have done a lot of laboratory experiments to study the factors of influence salt release from sediment to the impoundment such as different kinds of sediment, temperature, wind, to study the prevention and treatment measure for water salinization of polder reservoir. Some conclusions were obtained as follows:1)in column experiment the salt flux from different sediment decrease in the order of silty clay, medium-fine sand and pelitic silt; 2) when temperature is higher, the speed of water salinization is faster, in another words, the salt release from sediment to the overlying water is proportional to the temperature; 3) wind can accelerate the speed of water salinization and water mixture, the salt concentration homogeneous above the high-salt concentration gradient layer near sediment-water interface; The overlying water salt concentration obviously decrease by extracting nearly interface high salinity water or sediment pore water, the salt flux near sediment-water interface decreases with the increment of water infiltration rate.A simple mathematical model is developed to describe the saline distribution of interstitial water in sediment, the model was tested for steady-state conditions, the results indicate that the predicting value is more coherence to experiment dates. We estimated the time that salt concentration of interstitial water at bottom sediment began to change based on the model and the real data of proposed polder reservoir at Henghe estuarine in jiaonan. Finally, we supplied the prevention and treatment measure for water salinization of proposed reservoir project on the basis of experience data and the reason that lead to impoundment salinization of other polder reservoirs.In conclusion, the implement of operational measures such as digging ditch rows before the impoundment can effectively weaken the salinization of the fresh water, and the effect will be stronger if the high-salinity overlying water is removed.