Abstract: Urban water systems are significant elements for human settlements related to water supply, flood safety, shipping, waterfront landscape and economic development. In the Chinese context, a Blue-line Plan is always used by different water sectors, as well as the spatial planning sector, to regulate urban development and organise waterfront ecologicalisation, water resources protection and flood prevention. However, departmental segregation and vague policy documents often lead to the mismatches of blue lines across vertical layers and horizontal sectors, which create long-term institutional disputes in water governance. Those disputes come with uncontrolled urban sprawl and environmental problems, for instance, the erosion of water bodies, the degradation of hydrological connections, and the weakness of waterways' discharge capacity. 
　　To resolve these water problems and improve water governance, this paper, firstly, compares water-related policy documents in the field of spatial planning and water management, which clarifies their conflicts in the process of blue lines drawing. Secondly, the study proposes a five-component approach to mitigate institutional mismatches, namely, 'Three Lines Two Zones'. It consists of (1) bank control lines, (2) surface water control lines, (3) central water lines, (4) waterfront/shoreline areas, and (5) flood stage areas. This tool, as a way out of traditional planning, is helpful to clarify the responsibilities of spatial planning and water management spatially and offer joint-work opportunities in water affairs. Thirdly, this paper explains how this approach fits in the newly renovated territorial spatial planning system in a mainstreaming way and how this tool enhances the involvement of planning sector in water affairs.
 　　The paper concludes with the future of this new approach in implementation, for instance, combining it with detailed water resource assessment at the early stage of planning, with comprehensive public participation to build the common knowledge of historical water systems, and with policy determination concerning economic and ecological benefits.

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摘要： 城市蓝线划定及相应的规划治理是贯彻生态文明理念、落实水体资源保护、协调城水发展关系的重要措施。然而，现有的蓝线治理模式存在层级管理体系模糊、权责部门交叉管理、多部门规划编制标准不一等问题。在落实国土空间规划体系、寻求精细化城市治理的新时代，涉水区域的蓝线划定与开发管控亟待深入研究以指导实践。通过解读水利与规划专业对于城市蓝线定义的差异，引介国外水系管理经验，提出“三线两区”的城市蓝线编制方法，以明确涉水部门的管理权责，强化国土空间规划涉水事务的统筹能力，形成统一的管理规范，从而实施更积极、有效的城市蓝线治理模式。

关键词: 城市蓝线划定, 国土空间规划, 水利管理, 治理模式