一种改进的分水岭图像分割算法

分水岭算法在医学图像分割中有着广泛的应用。针对传统分水岭分割算法对噪声敏感和严重的过分割问题．本文提出了一种基于数学形态学的改进的分水岭图像分割算法。通过前期的预处理和汇水盆地的选取，有效地抑制了过分割现象。实验表明，该算法能够对血细胞图像进行快速、准确的分割，边缘定位精确，并且能够较好的克服噪声对图像的影响。     

基于流域水资源承载力的动力学模型

在探讨流域水资源承载力理论内涵的基础上,根据影响流域水资源承载力的资源、环境、人口和科技等主要因素,将水资源承载力的分析置于生态—经济—社会的复合巨系统的背景下,制定了流域水资源承载力的分析框架,揭示了水资源承载力的内部逻辑关系,并将这种内部逻辑关系用函数关系表征,最后根据水资源承载力的分析框架和内部关系建立了流域水资源承载力的动力学模型.     

流域湿地的景观生态特性分析与景观特征指数的运用——以杭州沿山河流域和西溪湿地为对象

以杭州市沿山河流域为例，应用景观生态学与碎片几何学的理论，采用景观特征指数的量化评价方法，分析了城市化对流域湿地原有景观地貌的干扰和破坏，以及水涝灾害发生的景观生态机理.城市化导致了系统形态结构的巨大改变，严重影响了流域的生物多样性、水文生态过程和视觉美学特质.景观结构的巨大改变引起了流域湿地贮、排水功能的衰退，主要表现为滞洪、消能空间的丧失，径流量的增加和汇水时间缩短等.探讨了量化分析景观特征、维护流域水文平衡的景观生态保护的新途径.     

洱海流域用地变化的智能体建模与非点源污染响应模拟

洱海流域水环境污染具有显著的人类活动-土地利用/覆被变化-非点源污染链式驱动效应,有必要分析其驱动机制,模拟和预测流域的用地变化及其非点源污染响应过程。本文利用智能体模型模拟人地交互作用过程,预测洱海流域未来土地利用/覆被动态变化的结果,进而利用SWAT模型计算不同用地情景下流域主要非点源污染指标(氮和磷)的产出量和时空分布,最后,利用统计学分析方法与GIS技术,对综合模拟结果进行了精度验证、敏感性检验以及空间分析与可视化表达。结果表明:(1)流域过去和未来10年的土地利用/覆被变化表现为耕地的持续性减少(-19.28%)与建设用地的不断增长(35.27%);(2)氮和磷在时间与空间上具有相对一致性,说明流域土地利用/覆被变化对氮、磷具有相似的水环境效应;(3)未来10年流域非点源污染主要来自于农耕区,建议在保护耕地的同时,优化农耕区的种植结构和生产模式,以减少农业生产的非点源污染贡献率;(4)未来10年流域耕地面积持续性缩减,农业非点源污染呈现逐年降低趋势;同时随着建设用地不断增加,不透水表面的快速增长可能导致的城市非点源污染风险需要引起足够的重视。     

基于系统聚类的鄱阳湖流域水功能区划研究

水功能区划是水环境管理和水污染物总量控制的重要基础。以县级行政区划为最小划分单元,根据选定的社会经济指标,采用系统聚类的方法,将鄱阳湖流域内各县进行分类。结合流域内水质状况、各县的其它社会经济条件和历史的水功能区划成果,确定各县的主导用水功能,生成鄱阳湖流域水功能区划图。结果表明:鄱阳湖流域主要水功能为农业用水,而工业用水区主要分布在江西省北部,渔业用水区主要分布在环鄱阳湖区。该区划结果兼顾了水资源的流域和区域管理的优点,能较好的适应目前水资源区域管理的现状,对水资源的合理开发与有效利用提供科学依据。     

西北内陆典型流域水环境风险源识别研究

着重研究了风险源评价体系中行业类别、距离流域最短距离、距敏感目标流程等企业特性指标,构建了风险源识别体系。在各指标权重赋权方法方面,采用AHP法和熵权法组合赋权的新方法,建立了风险源指标的权重评价方法。应用模糊综合评价方法对西北内陆典型流域风险源进行了综合分析评价。初步建立起适合该流域水环境风险识别技术,为该流域的水环境保护提供有力的技术支撑。     

Impacts of water surface area of watershed on design flood简

In order to analyze the impact of the water surface area of a watershed on the design flood, the watershed was classified into a land watershed and a water surface watershed for flood flow calculation at the same time interval. Then, the design flood of the whole watershed was obtained by adding the two flood flows together. Using this method, we calculated design floods with different water surface areas of three reservoirs and analyzed the impact of water surface area on the flood volume and peak flow. The results indicate that larger water surface areas lead to greater impacts on the flood volume and peak flow. For the same watershed area, the impact of water surface area on the flood volume and peak flow is positively proportional to the flood frequency, i.e., the higher the frequency, the greater the impact becomes.     

结合聚类与改进分水岭算法的彩色图像分割

针对传统分水岭算法产生严重的过分割问题,提出了一种聚类和改进分水岭算法结合的彩色图像分割算法.该算法首先利用聚类算法在HSV颜色空间将特征相似的像素归为一类,然后对分水岭算法产生的分割区域进行种子区域生长,并利用区域合并将剩余的小区域进行合并,从而完成了对彩色图像的分割.实验证明该算法减少了分水岭算法的过分割现象,提高...     

北京市生态清洁小流域与美丽乡村建设

美丽乡村是党的第十六届五中全会提出建设社会主义新农村的重大历史任务时强调的,是促进农村经济社会科学发展、提升农民生活品质、加快城乡一体化进程的重大举措,是推进新农村建设和生态文明建设的主要抓手。生态清洁小流域建设与美丽乡村建设目标一致,是推进美丽乡村建设的重要抓手。2003年以来,北京市的水土保持工作以水源保护为中心,采取21项措施,实施五同步治理,大力开展生态清洁小流域建设,截至2013年年底,北京市建成了253条生态清洁小流域,有力促进了美丽乡村建设。     

Institutional arrangements for managing the great lakes of the world: Results of a workshop on implementing the watershed approach

The conceptual framework for lake management has evolved at an accelerating rate in recent years to include the basic principles of a watershed approach: (i) citizen and stakeholder involvement is important throughout the planning and management process; (ii) the geographic focus for management activities includes the lake and its entire watershed; and (iii) mechanisms need to be in place to promote cooperation among different government jurisdictions and organizations in the watershed. Creating effective institutional arrangements for implementing this watershed approach in lake regions is perhaps the most challenging and important issue facing the world’s lakes. LakeNet organized a workshop at the 8th International Conference on the Conservation and Management of Lakes in May 1999. This article is a synthesis of the results of the workshop and the eight case reports prepared by the workshop participants published in this special issue. Seven major threats to lakes were identified: (i) accelerated eutrophication; (ii) invasive species; (iii) toxic contamination; (iv) overfishing; (v) water diversion, (vi) acidification; and (vii) climate change. Institutions and institutional arrangements for addressing these issues and for implementing a watershed approach are just beginning to emerge on lakes around the world. All of the institutions described in the case reports were established or formalized during the 1980s and 1990s. The legal mechanisms creating these institutions range from cooperative agreements among jurisdictions for purposes of policy and planning to national laws and international treaties with full regulatory powers. The knowledge base, political will and financial resources for these activities were very small in comparison with the complexity of the task at hand.