A STUDY OF TURBIDITY MAXIMUM IN THE CHANGJIANG ESTUARY
长江河口最大浑浊带研究

Turbidity Maximum widely exists in various estuaries. It is a typical phenomenon reflecting the transporting process of fine sediments in estuaries. In the processes of estuarine sedimentation it play an important role in aggregation and sedimentation of fine particles. It also significantly affects the chemical behavior of heavy metal elements and organic materials as well as their transportation and deposition. As early as the early 1960's the Chinese sci ntists have paid attentions to the problems related to the Turbidity Maximum in the Changjiang Estuary. However, it is not until the 1970's that the specific studies began to be carried out. On the basis of previous studies, this paper considers the Turbidity Maximum as a system and therefore makes a systematic and comprehensive study on its environmental background, patterns of temporal and spatial variation, sediment source, the effect of flocculation on sedimentation of suspended sediments, the characteristics and distribution of fluid-mud and enrichment mechanism of suspended sediments. Problems that require further study have been proposed at the same time, such as a quantitative analysis of sediments with different sources, the relative importance of each mechanisms for the development of Turbidity Maximum and its temporal-spatial variation, the mechanism of deposition and re-suspension of medium to fine-grained sediments in the system of suspended sediments, fluid-mud and bottom sediments, the mineral composition and structure of fluid-mud, its rheological characteristics, application, flux as well as its behavior in the estuarine biogeochemical processes. The improvement of waterway associated with the study of Turbidity Maximum, especially the water depth and the practical approaches, are also important problems to be further studied.