H型超薄板防渗技术在卫生填埋场中的应用

上海某生活垃圾卫生填埋场运营过程中发生堤坝渗漏,对周围环境造成了污染。经比选采用H型超薄板防渗技术处理,防渗薄板墙深18m,墙厚100mm。竣工后经CSAMT法、现场开挖取样等方式检测,超薄板墙各项指标均满足要求。有效治理了渗滤液渗漏,提升了区域环境质量。     

淮河流域多闸坝河流COD综合衰减系数测算

提出在多闸坝河流上，利用枯水期断面化学需氧量同步监测数据测算COD综合衰减系数的方法，用该方法测算河南省辖河流域部分河流COD综合减系数在0．08－0．341/d。并用实际监测结果进行检验。     

The Cotingo Dam as a test of Brazil's system for evaluating proposed developments in Amazonia

The proposed Cotingo Dam in Brazil's far northern state of Roraima is examined with the objective of drawing lessons for Brazil's system of evaluating environmental, social, and financial consequences of development decisions. The Cotingo Dam illustrates the difficulty of translating into practice the principles of economic and environmental assessment. Examination of the financial arguments for the Cotingo Dam indicates that justifications in this sphere are insufficient to explain why the project is favored over other alternatives and points to political factors as the best explanation of the project's high priority. Strong pressure from political and entrepreneurial interest groups almost invariably dominates decision making in Amazonia. The analysis indicates the inherent tendency of the present system to produce decisions in favor of large construction projects at the expense of the environment and local peoples. The requirements intended to assure proper weight for these concerns, such as the report on environmental impacts (RIMA) and the public hearing, fail to serve this role. Cotingo also provides a test case for constitutional protections restricting construction of dams in indigenous lands.     

Angler survey contributes to socially acceptable modification of harvest regulations to preserve cutthroat trout fishery in Snake River,Wyoming, USA

This is a case study that describes a survey of anglers that was used to assist in modifying fishing regulations for indigenous trout in the Snake River, Wyoming. A mail survey of anglers who purchased 1991 Wyoming fishing licenses in the two counties adjacent to the Snake River was conducted during fall 1992. Differences in angler preferences were noted between anglers who purchased licenses in two adjacent counties with different socioeconomic structures, as well as between residents and nonresidents in each county. Anglers who purchased licenses in Teton County, where there is extensive tourism and immigration by relatively wealthy residents, tended to be more specialized and less harvest oriented. Anglers in Lincoln County, which is largely agricultural and has substantially less tourism and immigration of residents, tended to fish in many different ways and indicated more desire to harvest fish. Anglers from the two counties segregated themselves; those from Teton County primarily used the upstream portion of the study reach, and those from Lincoln County primarily used a short downstream portion of the reach. Modification of fishing regulations to reduce harvest of spawning-size cutthroat trout in the Snake River probably was acceptable to most anglers due to spatial segregation and their attitudes toward harvest.The unit is jointly supported by the University of Wyoming, the Wyoming Game and Fish Department, and the National Biological Survey.     

Can we take the pulse of environmental governance the way we take the pulse of nature? Applying the Freshwater Health Index in Latin America

Quantitative assessments have long been used to evaluate the condition of the natural environment, providing information for standard setting, adaptive management, and monitoring. Similar approaches have been developed to measure environmental governance, however, the end result (e.g., numeric indicators) belies the subjective and normative judgments that are involved in evaluating governance. We demonstrate a framework that makes this information transparent, through an application of the Freshwater Health Index in three different river basins in Latin America. Water Governance is measured on a 0–100 scale, using data derived from perception-based surveys administered to stakeholders. Results suggest that water governance is a primary area of concern in all three places, with low overall scores (Guandu-26, Alto Mayo-38, Bogotá-43). We conclude that this approach to measuring governance at the river basin scale provides valuable information to support monitoring and decision making, and we offer suggestions on how it can be improved.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01407-8) contains supplementary material, which is available to authorized users.     

Association of plutonium with sediments from the Ob and Yenisey Rivers and Estuaries

The present study applied sequential extraction techniques to investigate the binding and mobility of plutonium (Pu) in sediments from the rivers and estuaries of the Ob and Yenisey. As a study site, the Ob and Yenisey are particularly interesting as both rivers have weapons-grade Pu sources in their catchment areas, including the Russian Pu production and reprocessing plants at Mayak, Tomsk-7 and Krashnoyarsk, and the Semipalantinsk nuclear weapons testing site in Kazakhstan. Plutonium activity and ²⁴⁰Pu/²³⁹Pu ratios were determined using accelerator mass spectrometry (AMS). Sequential extractions showed that between 47 and 80% of the Pu in Yenisey River sediments and 35–53% of the Pu in soils around the Techa River are mobilized with weak oxidising agents, which can indicate that Pu is bound to organic material. In contrast, Pu in Ob and Yenisey Estuarine sediments was more strongly bound, with 60–100% being found in the HNO₃-extractable fraction. This change in speciation could reflect either that Pu bound to organic material in the Techa and Yenisey River sediments becomes more fixed to the sediments with time, or that organic-bound Pu is mobilized and released to the water when the sediments encounter the more saline water of the Ob and Yenisey estuaries. In general, ²⁴⁰Pu/²³⁹Pu ratios were relatively consistent between different extraction fractions, although, in whole sediments, an increase in ratio was observed with distance from the source. This reflects the increased influence of weapon fallout from catchment runoff within the river systems, as compared to the weapons-grade sources close to the production and reprocessing plants. Knowledge of Pu speciation in the Ob and Yenisey Rivers, and the processes controlling its behaviour in estuarine systems, can improve predictions of its transfer and subsequent environmental impact to Arctic Seas.     

ADJUSTMENT OF STREAM CHANNEL CAPACITY FOLLOWING DAM CLOSURE,YEGUA CREEK,TEXAS1

ABSTRACT: In Yegua Creek, a principal tributary of the Brazos River in Texas, surveys of a 19 km channel reach downstream of Somerville Dam show that channel capacity decreased by an average of 65 percent in a 34 year period following dam closure. The decrease corresponds with an approximately 85 percent reduction in annual flood peaks. Channel depth has changed the most, decreasing by an average of 61 percent. Channel width remained stable with an average decrease of only 9 percent, reflecting cohesive bank materials along with the growth of riparian vegetation resulting from increased low flows during dry summer months. Although large changes in stream channel geometry are not uncommon downstream of dams, such pronounced reductions in channel capacity could have long‐term implications for sediment delivery through the system.     

Modeling Pre‐ and Post‐Dam Removal Sediment Dynamics: The Kalamazoo River,Michigan1

Abstract:  The state of Michigan is interested in removing two low‐head dams in an 8.8 km reach of the Kalamazoo River between Plainwell and Otsego, Michigan, while minimizing impacts locally and to downstream reaches. The study was designed to evaluate the erosion, transport, and deposition of sediments over a 37.3‐year period using the channel evolution model CONCEPTS for three simulation scenarios: Dams In (DI), Dams Out (DO), and Design (D). The total mass of sediment emanating from the channel boundary, for the DI case, shows net deposition of 4,100 T/y for the study reach, with net transport (suspended and bed load) of 10,500 T/y passing the downstream boundary. For the DO case, net erosion is 19,200 T/y with net transport of 30,100 T/y (187% increase) passing the downstream boundary. For the D case, net deposition is 2,570 T/y (37% decrease) with transport of 14,200 T/y (35% increase) passing the downstream boundary. The most significant findings were: (1) removal of the low‐head dams will cause significant erosion of sediments stored behind the dams and increased sediment loads passing the downstream boundary and (2) sediment loads for the proposed channel design are similar to existing conditions and offer reduced fine‐sediment loadings.     

山水林田湖草生命共同体的科学认知、路径及制度体系保障

山水林田湖草生命共同体是对人与自然和谐统一关系的新认知,是生态文明理论的重要组成部分。以建立一个山水林田湖草生命共同体的研究范式为目的,系统剖析了山水林田湖草生命共同体理论与应用在基础探索、快速发展和多元繁荣三个阶段的研究重点与特征;再次审视了山水林田湖草生命共同体的内涵、阐明了概念新认知、基本特征、人与生命共同体关系;最后提出面向山水林田湖草生命共同体的“问题—目标—时空策略—目的”的实施路径,及构建以自然资源监测监管体系、自然资源资产产权体系、国土空间规划体系、国土空间用途管制体系、国土空间生态修复体系、法律法规体系等为主的制度体系,进而提升其科学性和实用性,为构建国土空间治理体系及治理能力现代化提供决策支撑。     

西藏"一江两河"地区人口空间分布的动态演变

人口分布的空间演变是人口发展过程中在时间和空间上的表现形式,人口的集聚与扩散是诠释区域人口空间分布格局与形态的重要方面.对其研究有助于揭示人口分布现状的本质、理解区域空间结构特征及演变趋势.本研究运用局部空间自相关方法,并结合GIS技术,以县域为基本单元,人口密度为衡量指标,对西藏"一江两河"地区1990-2008年间人口分布空间格局的演变进行了分析.分析结果表明,"一江两河"地区各县市(区)人口总量和密度均有明显增长,人口分布总体上呈现出不断集中的态势.局部自相关分析揭示"一江两河"地区开始显现以拉萨市和日喀则市为中心的两个显著的人口高密度区,显示出该区域人口分布的多中心空间结构特征.对以拉萨市、日喀则市和乃东县为中心的区域密度函数进行拟合.多中心区域密度函数的估计结果显示,"一江两河"地区空间发展正逐步由20世纪90年代单中心(拉萨市城关区)阶段,向目前的多中心向心集聚阶段转变,除拉萨市城关区外,日喀则市和乃东县集聚能力开始显现.