合流制排水系统降雨径流初期冲刷效应

通过对昆明主城区3个集水区合流制排水系统10次降雨径流过程水质水量的监测,计算了污染物的次降雨平均浓度(EMC),并采用无因次累积负荷体积分数曲线(M(V)曲线)和初期冲刷系数方法对初期冲刷现象进行了探讨。结果表明:(1)对于同一个常规污染指标,不同集水区的EMC平均值没有较明显差异,但都表现出较高浓度的污染特征。不同集水区总悬浮颗粒物(TSS)、COD、TN和TP的EMC平均值分别为140.18~174.11、144.65~161.78、21.44~23.18、1.80~2.35mg/L。(2)3个集水区所有观测降雨事件中,TP、TN、COD和TSS的初期30%径流量所对应的污染物累积负荷量(FF30)平均值分别为38.7%、37.1%、40.7%、44.6%;TSS和COD的初期冲刷强度明显较TP和TN变化更剧烈,不同污染物初期冲刷强度依次为TSSCODTPTN。(3)对于合流制排水系统,在区域特征相近情况下,汇水面积越小则初期冲刷效应越显著。而当汇水面积大到一定程度时,不同集水区之间初期冲刷强度没有显著差异。(4)降雨量、平均雨强和最大雨强与合流制排水系统的初期冲刷强度呈显著的正相关性,是影响其初期冲刷的重要水文参数;降雨历时和前期晴天与其初期冲刷强度没有显著相关性,两者对初期冲刷无明显影响。     

Reconnecting Cities to the Biosphere: Stewardship of Green Infrastructure and Urban Ecosystem Services

Within-city green infrastructure can offer opportunities and new contexts for people to become stewards of ecosystem services. We analyze cities as social–ecological systems, synthesize the literature, and provide examples from more than 15 years of research in the Stockholm urban region, Sweden. The social–ecological approach spans from investigating ecosystem properties to the social frameworks and personal values that drive and shape human interactions with nature. Key findings demonstrate that urban ecosystem services are generated by social–ecological systems and that local stewards are critically important. However, land-use planning and management seldom account for their role in the generation of urban ecosystem services. While the small scale patchwork of land uses in cities stimulates intense interactions across borders much focus is still on individual patches. The results highlight the importance and complexity of stewardship of urban biodiversity and ecosystem services and of the planning and governance of urban green infrastructure.     

基于群集动力学模型的密集场所人群疏散问题研究

密集场所人群疏散问题直接关系到大型公共场所的安全保障能力.应用群集动力学理论方法,在密集人群群体流动过程和个体流动过程分析的基础上,对已有的人群疏散数学模型进行改造,使之更加符合实际意义.以实际人群密集场所为例,进行数值仿真,寻求一定人流密度和疏散时间约束下的最佳疏散通道宽度以及关于开放疏散出口数量的最佳疏散策略,以达到最佳的疏散效果.为有效解决应急环境下密集场所人群疏散问题提供了理论依据,可用于指导密集场所建筑物的结构设计改进,以及疏散过程中的调度管理优化等.     

夯实三大工作体系基础开拓防震减灾事业新局面

本文围绕建设防震减灾三大工作体系,向大家展示了在建设地震监测预报体系、震灾预防体系、地震应急体系方面的具体做法与启示.     

IMPACTS OF AGRICULTURAL DRAINAGE WELL CLOSURE ON CROP PRODUCTION: A WATERSHED CASE STUDY1

ABSTRACT: Much of north-central Iowa is characterized by flat topography, shallow depressions, and poor natural surface drainage. Land drainage systems comprising of tile drains and agricultural drainage wells (ADWs) are used as outlets for subsurface drainage of cropland under corn and soybean production. Studies have shown that these drainage systems, mainly the ADWs, are potential routes for agricultural chemicals to underground aquifers. To protect the region's vital groundwater resource, researchers are evaluating alternative outlets ranging from complete closure of existing ADWs (and creation of wetlands) to continued use of ADWs and chemical management in a comprehensive policy framework. This paper presents the results of a study designed to provide government jurisdictions, farmers, and land managers information for assessing the impact of closing ADWs on crop production. The study couples a geographic information systems database for a 471-hectare watershed in Humboldt County, Iowa, with a groundwater flow model (MODFLOW) and an empirical crop yield loss model to predict long-term effects of complete closure of ADWs on crop production. The cropland areas inundated and the relative crop yield loss due to ADW closure are determined as a function of long-term climatic data. The results indicate that elimination of drainage outlets in the watershed could result in ponding of low-lying areas and poorly drained soils, making them unsuitable for crop production. Such wetness also decreases the efficiency of production in the no-ponding areas by isolating fields, and the crop yield loss can be reduced by an annual average of about 18 percent.     

Feasibility of geographic information systems approach for natural resource management

Geographic information systems (GIS) technology is altering the work environment for planning and decision-making tasks. This article is an account of a resource application that make use of the GIS technology. It provides some cost estimates and reasons for the fairly slow development toward an integrated resource data base for environmental planning and management. It tries to identify some of the constraints of such an integrated data-base approach toward environmental assessment.     

环境空气自动监测子站委托管理的质量控制

介绍了深圳市环境监测中心站在环境空气自动监测子站委托管理模式下采取的质量控制措施,包括根据要求安排人员、明确托管工作职责、修订相关管理制度、重新制定工作计划、确立考核及控制办法、制定托管合同中的制约条件等,以保证托管工作的顺利开展和子站的正常运行.提出将在考核界定和运行经费核算等方面作进一步探索和完善.     

轻型车燃用费托柴油的实际道路排放特征

利用便携式车载排放测试系统,对某款采用增压中冷和高压共轨技术的国Ⅳ轻型柴油车进行实际道路排放测试,研究其分别燃用石油基柴油、费托柴油和混合柴油（费托柴油与石油基柴油按一定比例混合而成）时,不同车速下的CO、THC、NOx和CO2排放特征和油耗变化情况。实验结果表明：对于3种柴油,所测4种气态物的排放均随着车速的增加而降低,当速度达到一定程度后趋于稳定;与石油基柴油相比,费托柴油和混合柴油的CO、NOx和CO2排放分别降低23%和5%,30%和24%,20%和20%,但THC排放均略有增加;通过碳平衡计算,费托柴油和混合柴油的体积油耗相对石油基柴油分别降低12%和17%。总的来说,燃用费托柴油和混合柴油时的气态污染物排放与石油基柴油具有相似的速度变化趋势,但费托柴油和混合柴油的整体尾气排放和油耗要低于石油基柴油。使用费托柴油或混合柴油是降低轻型柴油车实际道路排放的一个有效途径。     

Social-ecological system analysis of an invertebrate gleaning fishery on the island of Unguja,Zanzibar

Invertebrate gleaning is a small-scale fishery that commonly occurs in the intertidal zone across the tropical Indo-Pacific. In this study, we investigated and analyzed several components of this fishery on the island of Unguja, Zanzibar by employing the social-ecological systems framework from Ostrom 2009. In doing so, we conducted ecological surveys, catch assessments, interviews with gleaners, household surveys, focus group interviews and analyzed the governance structure. This social-ecological systems analysis showed that gleaning is important for food security, local culture and livelihood. Yet, the multiple approaches in our study revealed that the local intertidal zone is degrading and that the gleaned catch is changing. Local narratives indicate that economically important bivalves (Modiolus spp.) and gastropods (Strombus spp.) are in decline, which was paralleled with low abundances of both genera within the ecological survey of the intertidal and catch landing assessment. We recommend that invertebrate gleaning, a fishery mainly comprised of women should be included in fisheries management.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-022-01769-1.     

双金属系统还原脱溴降解多溴联苯醚(PBDEs)研究进展

多溴联苯醚(PBDEs)是一类新型持久性有机污染物。双金属系统催化还原脱溴技术作为一种处理环境中PBDEs的方法,具有出较好的应用前景。综述了双金属系统催化还原PBDEs脱溴的研究进展,详细阐述了双金属系统催化PBDEs脱溴降解的机理、途径以及不同双金属系统的脱溴效能。提出了利用双金属系统降解PBDEs存在的问题和发展前景。