【作者】 杨凯；

【导师】 俞立中；

【作者基本信息】 华东师范大学 ， 自然地理学， 2006， 博士

【摘要】 水网是无价的自然遗产，具有重要的遗产价值和历史价值，河网水系通过水系分叉、河流分级、河网密度、河流频度、河流数目以及河流长度等自然因素，影响着河流形态、水系结构、调蓄能力、水循环过程以及区域景观特征，具有鲜明的地域特点。发达国家在基本完成水环境质量控制后，已开始逐步恢复河流的自然状态。近年来国际上逐步开始将河流形态应用于河流健康评价，澳大利亚、美国、英国、南非等都将河流形态因子加入到河流健康状况评估程序中，河流水系的形态及结构已经成为河流管理和健康评价的重要内容。 河流生态系统是地球上受人类影响最为深刻的生态系统之一，千万年来，按照自然规律形成的水系自有一定的规律形态。但是由于人类活动的长期影响，部分河流水系的自然形态及结构已受到影响乃至破坏，河网水系在人为影响下一定程度上偏离了自然发育规律，这也是导致水灾加剧和水环境恶化的重要原因之一。 长江三角洲平原河网地区水网发达，江南水乡的自然与人文景观典型，保持河网水系的健康以及近自然的河网水系结构，对平原水网地区的生态环境建设至关重要。但为了争夺有限的土地资源，平原河网地区在城市化以及社会经济发展进程中，将河道排水改为管道排水，河流水面被人为侵占、河网末端大量村镇级小河流被填埋，河网水系自然的调蓄功能萎缩，高度城市化地区非主干河道不断减少，河网结构趋于简单，河网有单一化以及主干化的趋势，导致平原河网地区河流水系结构破坏以及功能退化的状况比较突出。 20世纪90年代以来，长江三角洲平原河网地区以上海为代表，已陆续开始实施城市河网水系的规划与整治修复工作，开展平原河网地区水系结构以及城市化响应的研究，是合理恢复和保护河网水系的重要基础工作。在城市化进程的不同阶段，受自然因素和人为干扰双重影响的平原河网地区，如何在河流自然分级的基础上，探讨平原河网地区高密度水系结构特征以及Horton规律表现，从景观、形态、结构、功能等方面界定河网水系结构类型，研究平原河网地区水系结构对调蓄效应的影响，以更好地把握平原河网地区河流水系结构可能出现的演变趋势，是平原河网地区在城市化过程中所面临的重要理论与实践课题。 论文依托国家自然科学基金项目、教育部高校博士点基金项目以及上海市水务局相关研究课题，以长江三角洲城市化的平原河网地区—上海为研究区域，基于自然地理学、河流地貌学以及生态水文学等学科有机联系的综合研究方法，对城市化深刻影响下的平原河网地区水系结构特征开展细致研究，以期为恢复和保护平原河网地区的水面率，保护河网水系的良好结构以及近自然的等级发育规更多还原

【Abstract】 Rivers are invaluable natural heritage. River networks have their effects on river style, stream structure, flood-control capacity and water cycling process through the factors such as stream bifurcation, stream order, river density, river frequency, stream number and length. After water quality having been extremely improved in developed countries, people now have taken it as important target to restore rivers to their natural situation. River style and structure have now becoming the key contents for river management and river health assessment. River systems are one of the most deeply modified eco-systems in the world. Based on natural laws, river systems have their regular features formed in the evolution process. Under the human modification, part of the natural style and structure of river systems have been affected even been destroyed. This is one of the main courses that caused more and more serious flood and water environment pollution.Yangtze Delta is a plain with well-developed river networks. To keep the health of river networks and natural-like stream structure, that is the precondition for eco-city construction in such regions. However, urbanization changed the landuse. A large amount of branches were engineered out, the natural flood-control capacity of river systems were weakened, stream structure is becoming more and more simple and the diversity of natural river style is seldom observed in urbanized area. Since 1990s, cities in Yangtze delta had begun to replan and restore urban river systems. Therefore, studying the characteristics of river systems and its urbanization response in Ynagtze Delta, that is academic base for restoring and protecting river systems. The following questions have been faced and need to be answered for realizing health urbanization in river network regions, (a) How to define river basin and stream order? (b) The characteristics of stream structure situation and river systems development;(c) the correlation between stream structure and flood control capacity of a river system; (d) How to classify river systems? Are there any regulations that may guide the evolution of river systems?更多还原