Sediment loads from the Yangtze River into the sea experienced a major increase in the late Holocene when sand beaches along the deltaic coast changed into tidal-flats. Sediment transport averaged about 472 million tons a year between the 1950s and the mid-1980s and decreased by 124 million tons a year after the mid-1980s, followed by a dramatic drop since the closure of the Three Gorge Dam (TGD). This paper discusses the major processes for the decline of sediment discharge since the 1950s and discusses the method for evaluating its future development over the Post-TGD Period. Sediment loads in the Post-TGD Period will be mainly determined by the major processes that may significantly contribute to the following three components, i.e. (1) the sediment input from the upper basin into the Three-Gorge Reservoir (TGR); (2) the ratio of sediment export from the TGR relative to the input and (3) the amount of sediment recovery downstream the TGD restrained by available sediment sources. An integrated evaluation shows that the annual sediment loads over the Post-TGD Period will possibly vary from 1.12 to 1.32 million tons a year or less in ordinary years.

依据长期系统观测资料，研究了长江进入河口段床沙粒径的变化、原因及其未来发展趋势.研究揭示出大通断面1月份床沙粒径d<0.100mm的百分含量较7月份多,而0.100mm≤d<2.00mm之间的含量较7月份少.床沙与悬沙之间交换是导致这一季节变化的主要原因.1976年以来,长江进入河口段的床沙粒径（d50）显示出显著的粗化趋势,与同期长江入海悬沙量下降密切相关.入海悬沙量下降增大本河段侵蚀能力、减少淤积量和促进粗细床沙交换.1976年以来最大床沙粒径没有出现相同的变化趋势，且变化幅度显著变小，这一现象与葛州坝有密切关系.未来人类活动对河流系统的影响将使长江输入河口段的床沙继续向粗化的方向发展.

Sand extraction from the mid-lower Yangtze has increased rapidly since the 1980s, in contrast to a rapid decrease in sediment discharge from the Yangtze River into the sea. In-channel sand extraction poses great risks to flood protection, navigation channels and railway bridges. This paper reviews the recent history of in-channel sand extraction, discussing the present status and potential problems in legislation and management. It is concluded that the share of interests, the involvement of local criminal gangs and official corruption were the main difficulties for the ban on illegal sand extraction. It is proposed that the sites and amounts permitted for in-channel sand extraction should be re-evaluated under the new sediment budget after closure of the Three-Gorges Dam. It is necessary to explore the use of alternative materials in order to reduce the demand for natural sand while meeting the market needs for socio-economic development.

回顾总结了我国近来在水资源本国方面的理论研究和工作进展，论述了我国水资源配置的特点及其与联合国倡导的水资源综合管理的相互关系，阐述了长江流域水资源综合管理在我国的重要地位。提出我国开展的水资源配置在重视公众参与基础上，与水资源综合管理是一致的。长江流域水资源综合管理是一个多学科的研究课题。流域层面的水资源综合管理是国家层面和行业层面水资源配置的基础。长江水资源综合管理应该遵循水文系统优先的原则，使水资源利用和管理在流域层面上道达到优化状态。环境用水需求是一个很需要课题，它是流域层面水资源配置的基础，急待开展　量的研究。在流域系统优先原则下，各行政区与水用户参与者在讨论和协商的基础上，确定共同的准则、目标和具体措施，在不损害它方利益的前提下都能取得自己的利益。具体细化新《水法》中提出的流域管理与行政管理相结合的原则是开展长江资源综合管理的关健。《长江法》的制定与应该为水资源综合管理提供具体的法律依据。流域与地方水利机构的体制改革是十分重要的，它应该为开展水资源综合管理创造条件。在我国国情条件下，水资源综合管理中的用户参与应该如何开展，需要研究和实践。