Application of the Stream Evolution Model to a Volcanically Disturbed River: The North Fork Toutle River,Washington State,USA

In this study, a recently revised version of the channel evolution model, named the Stream Evolution Model (SEM), was applied to the upper North Fork Toutle River disrupted by the deposition of a 2.5‐km³ debris avalanche during the catastrophic eruption of Mount St. Helens in 1980. The results show that, in the first few years following the eruption, upstream channel reaches generally incised, evolving in SEM Stage 4 (i.e. degradation and widening), while downstream reaches aggraded, evolving in Stage 5 (i.e. aggradation and widening). However, starting in the late‐1980s, this simple pattern was disrupted by incision in the downstream reaches, which seemed to propagate upstream. Since the 1990s, lateral channel adjustments have become predominant as rates of vertical adjustment have slowed and river valley top widths relaxed to asymptotic values. Spatial and temporal sequences of channel evolution have tended to follow the sequences of stages expected according to the SEM, although these sequences have been frequently disrupted by renewed incision, secondary cycles of adjustment and the impacts of local geologic, geomorphic and hydraulic conditions. Within the quasi‐full SEM cycles, stages 4 and 5 were sometimes repeated, while stage 6 (quasi‐equilibrium) was sometimes omitted, and stage 8 (anabranching) only occurred in the downstream braided/anabranching reaches. According to the SEM, degradation, widening and lateral activity (stages 4 and 7) are forecast to continue until transverse valley profiles and channel planforms stabilize and floodplain and terrace surfaces are fully colonized by vegetation. Copyright © 2017 John Wiley & Sons, Ltd.     

Sharing Rivers for Peace,Development, and Security

Abstract

Water is a finite resource, and with the considerable upsurge in population, urbanization, and industrialization, it is also becoming an increasingly scarce resource. Many countries in the world rely on river waters, and many of those rivers are shared by two or more countries. Dams on those rivers have been a major source of tensions, disputes, and, in some cases, even conflict between riparian countries because dams could result in massive diversion of river flows. Those developments have, inter alia, highlighted the relevance and importance of the principles of international water law, as reflected in the United Nations Convention on the Law of the Non-Navigational Uses of International Watercourses. The World Commission on Dams has also underscored the importance of, and elaborated on, those principles with regard to dams on shared rivers. This article discusses and analyzes the recommendations of the Commission in this area, and compares them with the principles of international water law as enunciated in the United Nations Convention     

我国锦纶帘子布市场前景预测与应对措施

文章从国内外帘子布行业的现状及其格局的重新调整，汽车、公路运输业、轮胎相关行业的现状及发展前景，加入WTO和国家宏观政策变化对帘子布行业的影响等方面进行全面、深层次的分析，应用两种数学公式模型对未来15年的国内帘子布市场需求量的上下限进行预测，并提出应对措施。     

An improved parameter estimation procedure in lake modelling

This paper proposes an alternative parameter estimation procedure. Usually the parameters that yield the highest sensitivity are calibrated by trial and error or by an automatic calibration procedure. If the number of parameters to be calibrated is more than 3-5, this procedure is very time consuming. The presented procedure is based on the assumption that the biological components in an ecosystem model attempt to develop such properties that they become best possible survivors, i.e. develop as much biomass as possible. It has previously been proposed that the survival of the entire ecosystem can be measured by use of the thermodynamic function exergy, which measures the distance from thermodynamic equilibrium and accounts for the biomass and its information content. If these assumptions are correct, it should be possible to determine the combination of parameters which gives the highest exergy. The paper presents the use of this idea in combination with a normal calibration. The parameters, which are less known from the literature and still yield a relatively high sensitivity, are determined by use of the above-mentioned exergy principle. The parameters that are known within relatively narrow ranges from the literature are calibrated by the normal procedure. The method has been used on a concrete lake modelling study and given good results. This combination method seems therefore to offer clear advantages, particularly for models with a relatively high number of sensitive parameters (> 5), which otherwise would require a very cumbersome calibration.     

大朝山水电站工程招标工作的思考

大朝山电站建设实行招标承包制，坚持“公开、公平、公正”原则，择优选中承包单位，并通过经济合同来规范合同双方的责任和义务，为有效控创工程建设的造价、进度、质量，实现投资效益，提供了基本保障．     

国内湖泊水质污染及富营养化治理

湖泊水质污染及生态恢复是我国当前水环境保护所面临的主要问题。在国内湖泊富营养化防治调研的基础上,对我国重点治理的“三湖”水环境状况及治理对策进行了总结与分析,提出国内湖泊治理存在的问题和对策,以及官厅水库水污染防治应注意的问题。     

太湖西苕溪流域环境流量评价分析

针对丰水地区河道外取水量过多与河道内污染严重的现状,环境流量研究可为其水环境的改善和资源优化配置提供更加直接有效的支持。区别于生态需水量等侧重研究自然状态下流域植被、土壤、河道内生物以及降雨径流的过程研究,本文从人类活动强烈干扰下的河流健康角度出发,以水量丰富的太湖西苕溪流域为例,采用客观熵权法赋多指标权重对综合水质标识指数法进行合理性修正,并将水资源利用率和回污系数引入水量计算,定量分析东部地区环境流量的"质"与"量"。结果表明:除浒溪和西苕溪干流外,西溪、南溪和龙王溪的环境流量均达标。而基于熵权求权法修正后的水质评价使得西溪的评价结果从不达标转为达标,说明水质作为环境流量综合评价中的优先级限制因素,对应选取的主要污染因子指标权重大小对评价结果是否达标起到决定性作用。修正后的评价方法有效避免了最差因子对结果产生的越级性影响,为探讨水质水量条件组合下丰水地区环境流量评价提供新思路。     

太湖流域水事违法案件查处工作实践与思考

太湖流域经济发达,河湖开发利用程度高,未批先建等违法行为时有发生。水利部太湖流域管理局以直接查处水事违法案件为抓手,创新体制机制,深化流域与区域执法合作,不断加大执法力度,有效遏制了水事违法行为上升势头,维护了水事秩序,为流域水生态文明建设提供法治保障。     

桂林桂湖浮游藻类种群组成及水质生物学评价

根据2013年1～12月对桂湖浮游藻类的调查和监测结果,分析藻类种群组成和优势种、细胞密度、马卡列夫（Margalef）和香农—韦弗（Shannon-Weaver）生物多样性指数等生物特征参数的变化,从生物学角度对桂湖水质进行评价,为桂林两江四湖水环境的综合治理和生态保护提供基础资料和理论依据。     

城区穿河隧道工程安全施工关键技术探究

随着城市地下空间的开发,盾构穿越已有河道的现象越来越普遍。如何合理地安排施工过程,确保河道上建筑物和施工安全尤为重要。以南京地铁四号线某区间盾构穿越秦淮河线路工程为例,总结克服施工过程中盾构隧道下穿河道和侧穿桥墩技术难题的经验,保证其安全、顺利地通过秦淮河河段。