Spatio-temporal variations of salinity and analysis of desalination factors in a Chinese coastal storage reservoir

Abstract

Coastal reservoirs could be used to store freshwater in coastal cities, but the conversion of coastal reservoirs to freshwater reservoirs is relatively time-consuming, and coastal reservoirs are facing a risk of salinization. Taking Zhuyu Lake as the research object, the Spatio-temporal variations of water salinity under different seasons were investigated using the field survey and modeling. The influencing factors of the water salinity of the reservoir were analyzed to discover the variation mechanism. The results showed that the disturbance of overlying water is the most significant factor affecting the salt release of sediment, and salt release was increased by 63.3% with the disturbance. The depth of the overlying water and the salt content of bottom sediment also significantly affected the release of salt, with maximum enhancement by 23.1% and 45.6%, respectively. The microbial content in the bottom mud played an essential role in maintaining the salt, and inhibiting the microbial activity could enhance the release of salt by 35.7%. Therefore, disturbing the sediment by using disturbance ships or aeration devices, and the establishment of a long-term periodic plant harvesting belt could be used in the coastal fresh reservoirs desalination and slowing down the salinization of fresh reservoirs.