关於“对照”存在的条件──与陈发祖同志商榷

陈发祖同志推导出来的模式，经过热量平衡法测定结果的验证，但陈同志忽略了“对照”存在的条件。施剂地与对照地蒸发差异很大，在无水份补给条件下，对照地土壤水份较小，“对照”已不存在。热量平衡法测定的抑制率偏小，其原因为综合了试验区外环境影响，测的仅是蒸发差比率，而不是抑制率。     

关於“对照”存在的条件（1）：与陈发祖同志商榷

陈发祖同志推导出来的模式，经过热量平衡法测定结果的验证，但陈同志忽略了“对照”存在的条件。施剂地与对照地蒸发差异很大，在无水份补给条件下，对照地土壤水份较小，“对照”已不存在，热量平衡法测定的抑制率偏小，其原因为综合了试验区外环境影响，测的仅是蒸发差比率，而不是抑制率。     

基于WebGIS水利信息系统的设计与实现

通过对比分析目前WebGIS的常用开发方法和软件平台的特点，结合实际需求选择．NET和AreIMS技术，利用ArcIMS中的Serdet连接器和ArcXML语言的优点，在．NET环境下对ArcXML的生成进行封装，并结合ASP．NET技术设计了通用的WebGIS控件。该控件较好地实现了WebGIS中表现层与服务层的分离，可以方便地进行二次开发和与其他．NET系统集成，从而大大降低了WebGIS在．NET平台下的实现难度，并使系统具有了更好的可扩展性，通过在博州水利信息系统的应用实例介绍了实现过程。     

北京绿创声学工程设计研究院在京成立

2009年6月10日，北京绿创声学工程设计研究院成立大会在京举行。北京绿创声学工程股份有限公司自2004年底创办以来，在绿创集团、首钢特钢、劳保科研所、中科院声学所、上海联创永宣及信中利等股东的支持下，在政府和客户的扶持和信任下，得到了快速地发展，成为了行业领先企业。为了更好地服务社会，由绿创声学公司全资投入，建立了中国第一个由企业创办的从事噪声与振动控制的专业设计院——北京绿创声学工程设计研究院。     

一路环保伴我行

地球妈妈痛苦地呻吟着。烦恼的她，只要轻轻将手一挥，2009年的1月，西藏同胞们就遭受到了冷酷无情的大雪灾。懊恼的她，只要轻轻吹口气儿，雨就像发疯似的，不停地下，淹没了多少农田和庄稼。现在天气暖和了许多，北极的冰山快速融化，只见北极熊坐在冰上一动也不动。正是因为这样，我们才更要环保、低碳。     

化学质量平衡模式的复共线性问题及岭回归估计

讨论了岭回归在解决化学质量平衡模式的复共线性问题中的应用，结合成都市大气颗粒物的实测数据，对数据作标准化与不作标准化时的岭估计结果进行了比较，表明，不作标准化处理的岭回归方法较之经典方法（标准化处理），其岭迹能较快地趋于平稳，从而在较小的岭参数下得到较好地岭估计结果。     

切实抓好环境教育，提高学生素质

切实抓好环境教育，提高学生素质上海市延安中学我校是所市重点中学，１９９１年被授予“上海市环境教育特色学校”光荣称号”。从那时以来，在区教育局领导下，在市、区环保局和少科站的指导、帮助下．环境教育在原有基础上，不断地取得了新进展，它已成为我校教育和教学...     

环保部部长周生贤对2012年“六·五”世界环境日纪念宣传活动总结作出重要批示

2012年的世界环境日宣传纪念活动，在部领导高度重视和有关方面的大力支持下，圆满地落下了帷幕。“六·五”期间，环保部主办的8项活动以服务环保中心工作为宗旨，     

市场经济条件下的企业环境管理

一、市场经济条件下企业环境管理的意义我国正全面地进行经济体制的改革，其目标是建立社会主义的市场经济体制。这一目标，给企业环保工作带来了动力也带来了压力。一方面，在市场经济条件下，企业受到市场竞争的压力，企业在进行生产经营活动中必须全面考虑各种因素，包括污染物的排放给企业造成的影响。一个企业如果排放的污染物越多，表明其原材料浪费越大，结果必然是提高了产品成本，降低了企业竞争力。所以，社会主义市场经济体制的建立，为企业加强环境管理提供了内在动力；另一方面，在市场经济条件下，企业成为自主经营，自负盈亏…     

国家重点环境保护实用技术推荐地区情况分析

十年来，国家重点环保实用技术推广工作在国家环境保护总局的领导下，健康、深入地发展，呈现出旺盛的生命力。它有力地推动了环保科技成果向现实污染治理能力的转化，调动了社会各界推广应用环保实用技术的积极性，推动了环境保护科研开发的深入开展，带动了环境治理工程设备的更新换代，促进了环保实用技术产业化、工程化、集团化，取得了显著的环境效益、社会效益和经济效益。为环境保护科技体制改革和科技与环保的结合，为我国环保产业的发展做出了重要的贡献。２００３年国家重点环境保护实用技术评审工作已经结束，从全国各地方各部门…     

Estimating the Benefits of Environmental Enhancement: A Case Study of the River Darent

The provision of leisure facilities is usually assessed on their value to users. This paper outlines the use of contingent valuation methods in an ex ante appraisal of the costs and benefits of enhancing river flow for recreational purposes in a low flow river. A number of rivers in England and Wales experience low flows, especially during summer months, due to over abstraction of water, creating a trade-off between leisure uses and the demands of water consumers. The sequential benefits of enhanced flows are estimated from those associated with abstraction up to licensed limits: to river flow at 70% of licensed abstraction levels; to flow levels required for an environmentally acceptable flow regime, which would permit leisure activities such as fishing, enhanced scenic walking and wildlife encounters. These benefits are compared to the costs which would be incurred to achieve these enhanced flow regimes. The study illustrates the importance of including non-user benefits in benefit-cost analysis, if leisure provision is to be provided in certain areas.     

水流概念与水资源概念的法学抉择

我国法律有关所有权的规定将"水资源"与"水流"等同,学者也持此观点。在中国大百科全书中,水资源是比水流更为常见的概念。《水法》中的水资源是指地表水和地下水资源,不包括大气降水。水流是水力学上的一个概念,强调人们利用水资源流动而产生的动力。《宪法》之所以选择"水流"而非"水资源",源于人们从水力学角度看待水资源,强调利用水资源因流动而产生的能量。在水资源短缺的当下,随着雨水工程设施的广泛利用,以及水生态功能的凸现,都要求使用比"水流"外延更大的"水资源"概念,以实现水资源的持续利用。     

Minimizing disruptions caused by damming and ensuring the health of downstream ecosystems

In view of the Brazilian Ten‐Year Energy Expansion Plan 2021, this article presents a discussion on environmental flow (e‐flow). The authors analyze the literature to show the evolution of publications concerning e‐flow releases from the perspective of ecosystems services preservation considering results from different case studies from throughout the world. Finally, two main recommendations are drawn regarding e‐flow are: (1) performing a holistic approach to e‐flow planning, including hydrological, hydraulic, water quality, habitat, and riparian zone considerations; and (2) installing in new structures adequate bottom outlets to allow a range of adjustable e‐flow from reservoir dams to reproduce natural flow variations.     

Impacts of Dams on Flow Regimes in Three Headwater Subbasins of the Columbia River Basin,United States1

Moore, Johnnie N., Alicia S. Arrigoni, and Andrew C. Wilcox, 2012. Impacts of Dams on Flow Regimes in Three Headwater Subbasins of the Columbia River Basin, United States. Journal of the American Water Resources Association (JAWRA) 48(5): 925‐938. DOI: 10.1111/j.1752‐1688.2012.00660.x Abstract: We compared long‐term changes in flow regimes resulting from climate change with those resulting from dams in three matched pairs of natural and modified headwater subbasins of the Columbia River. Based on the analysis of 12 flow‐regime metrics, we found that damming had minimal effect on most quantity of flow metrics, but major effect on timing of flow metrics, especially those representing “spring runoff.” In all modified subbasins, “spring runoff” metrics occurred much earlier than natural flow (up to ～44 days earlier for April‐July flows). Storage capacity modulated the magnitude of timing of flow‐metric changes, with the largest storage capacity leading to the most change. However, even in subbasins with low storage capacity, we found significant change in most timing of flow metrics. We also found that damming, especially in subbasins with higher storage capacity, overwhelmed climate variability in all basins for most flow metrics. This shows that reservoir operations need to be modified to more closely match the natural timing of flow regimes to promote positive ecologic response in modified rivers, even in basins where quantity of flow metrics have not changed substantially as a result of damming.     

Analysis of the Effect of the Beavers‐Joseph Interface Condition on Flow in Karst Conduits1

Li, Guangquan, Yuan Cheng, and Bei Zhao, 2012. Analysis of the Effect of the Beavers‐Joseph Interface Condition on Flow in Karst Conduits. Journal of the American Water Resources Association (JAWRA) 1‐8. DOI: 10.1111/j.1752‐1688.2012.00683.x Abstract: In this study, we derive an approximate analytic solution for the distribution of flow velocity in a cylindrical conduit and the surrounding media, and analyze the effect of differing parameters (e.g., conduit radius) on the velocity of conduit flow. The solution is then employed to estimate the thickness of the boundary layer inside the media. The results reveal that when conduit radius is large, the Beavers‐Joseph condition has only a minor effect on the velocity of conduit flow (such that the nonslip condition on the conduit wall still works pretty well), and the boundary layer is so thin that the wall can still be treated as the interface between fast water in the conduit and slow water in the media. The solution indicates that the velocity of conduit flow is the superposition of the velocity profile in the nonslip situation onto the slip velocity on the wall. Our study theoretically shows that the coupled continuum pipe flow model in MODFLOW‐2005 constructed by the U.S. Geological Survey is reasonable in that there is no need to consider the Beavers‐Joseph condition when simulating flow in karst conduits. The role of the boundary layer in transport and its effect on the hyporheic zone is not clear, which is a suitable topic for future study.     

Impact of nonuniform reactant flow rate on the performance of proton exchange membrane fuel cell stacks

ABSTRACT

In this study, a proton exchange membrane (PEM) fuel cell stack composed of five cells in series is numerically investigated to study the impact of the nonuniform reactant flow rate on the performance of the stack. A comparison of the water concentration, temperature, reaction heat source, and current density of change rule of two groups of fuel cell stacks with uniform and nonuniform reactant flow rate reveals the performance degradation mechanism caused by nonuniform reactant flow. The results indicate that while operating under low-voltage conditions, the nonuniform reactant flow rate will cause the accumulation of excess liquid water near the PEM that is near the cathode exhaust outlet, and the local area reacts strongly on the catalyst, whereas the local area reacts slowly. When the average voltage of the stack is 0.55 V, the current density under the nonuniform reactant flow rate condition is 12.9% lower than that of the uniform reactant flow rate condition. In the case of uniform and nonuniform reactant flow rate at low current densities, the performance difference is not evident, but it is expected to be pronounced with the increase in current density. The simulation results are compared with the experimental data reported in the literature through a polarization curve, and they turn out to be well correlated with the experimental results.     

Application of the ELOHA Framework to Regulated Rivers in the Upper Tennessee River Basin: A Case Study

In order for habitat restoration in regulated rivers to be effective at large scales, broadly applicable frameworks are needed that provide measurable objectives and contexts for management. The Ecological Limits of Hydrologic Alteration (ELOHA) framework was created as a template to assess hydrologic alterations, develop relationships between altered streamflow and ecology, and establish environmental flow standards. We tested the utility of ELOHA in informing flow restoration applications for fish and riparian communities in regulated rivers in the Upper Tennessee River Basin (UTRB). We followed the steps of ELOHA to generate univariate relationships between altered flows and ecology within the UTRB. By comparison, we constructed multivariate models to determine improvements in predictive capacity with the addition of non-flow variables. We then determined whether those relationships could predict fish and riparian responses to flow restoration in the Cheoah River, a regulated system within the UTRB. Although ELOHA provided a robust template to construct hydrologic information and predict hydrology for ungaged locations, our results do not suggest that univariate relationships between flow and ecology (step 4, ELOHA process) can produce results sufficient to guide flow restoration in regulated rivers. After constructing multivariate models, we successfully developed predictive relationships between flow alterations and fish/riparian responses. In accordance with model predictions, riparian encroachment displayed consistent decreases with increases in flow magnitude in the Cheoah River; however, fish richness did not increase as predicted 4 years after restoration. Our results suggest that altered temperature and substrate and the current disturbance regime may have reduced opportunities for fish species colonization. Our case study highlights the need for interdisciplinary science in defining environmental flows for regulated rivers and the need for adaptive management approaches once flows are restored.     

Management of the Spring Snowmelt Recession in Regulated Systems

In an effort to restore predictable ecologically relevant spring snowmelt recession flow patterns in rivers regulated by dams, this study defined a methodology by which spring flow regimes can be modeled in regulated systems from the quantifiable characteristics of spring snowmelt recessions in unregulated rivers. An analysis of eight unregulated rivers across the Sierra Nevada mountain range in California found that unregulated systems behaved similarly with respect to seasonal spring patterns and recession limb curvature, and thus prescribed flows could be designed in a manner that mimics those predictable characteristics. Using the methodology to quantify spring recession flows in terms of a daily percent decrease in flow, a series of flow recession scenarios were created for application in an existing hydrodynamic model for the regulated Rubicon River. The modeling results showed that flow recessions with slow ramping rates similar to those observed in unregulated rivers (less than 10% per day) were likely to be protective of native aquatic species, such as the Foothill yellow‐legged frog, while flows that receded at greater rates would likely result in desiccation of egg masses and potential stranding of tadpoles and fry. Furthermore, recession rates of less than 10% per day provided the most spatially diverse hydraulic habitat in the modeled domain for an appropriate duration in spring to support all native species guilds and maximize aquatic biodiversity.