Predicting the migration of dissolved toxic substances from catchments by a collective model

In the present paper a collective model for predicting the migration of dissolved toxic substances through drainage areas is described. The model has been validated using data for ¹³⁷Cs and ⁹⁰Sr concentrations in water of some European contaminated rivers following the atmospheric fall-out from the accident at the Chernobyl power plant. It has been demonstrated that the migration rate λ (s⁻¹) of a dissolved toxic substance from a catchment may be evaluated by the following approximate formula: λ=(c ln t+d)/t, where t is the time from a pulse deposition event and the coefficients c and d depend on the characteristics of the substance. It has been shown that the mathematical form of the transfer function (flux of dissolved substance at time t following a single pulse deposition of a pollutant onto the catchment) of a toxic substance from a drainage area is very simple. Moreover, the values of the transfer function parameters are slightly variable despite the large range of characteristics of the catchments here examined. Indeed, the statistical aggregation of competing migration processes can lead to ‘stable’ collective behaviours that are less variable than each single process.     

Adoption of Stream Fencing Among Dairy Farmers in Four New Zealand Catchments

The effect of dairy farming on water quality in New Zealand streams has been identified as an important environmental issue. Stream fencing, to keep cattle out of streams, is seen as a way to improve water quality. Fencing ensures that cattle cannot defecate in the stream, prevents bank erosion, and protects the aquatic habitat. Stream fencing targets have been set by the dairy industry. In this paper the results of a study to identify the factors influencing dairy farmers' decisions to adopt stream fencing are outlined. Qualitative methods were used to gather data from 30 dairy farmers in four New Zealand catchments. Results suggest that farm contextual factors influenced farmers' decision making when considering stream fencing. Farmers were classified into four segments based on their reasons for investing in stream fencing. These reasons were fencing boundaries, fencing for stock control, fencing to protect animal health, and fencing because of pressure to conform to local government guidelines or industry codes of practice. This suggests that adoption may be slow in the absence of on-farm benefits, that promotion of stream fencing needs to be strongly linked to on-farm benefits, and that regulation could play a role in ensuring greater adoption of stream fencing.     

沘江流域环境保护综合治理措施探讨

阐述了沘江流域环境现状,分析了存在的主要问题及其成因。在坚持“保护、治理、开发”三结合的原则下,提出了要建立全方位的污染控制体系,对受污染影响的生产生活用水提出替代方案,对受到污染影响的土地进行治理,完善监控体系。兴建工业点源治理、矿区生态恢复、城镇污染源控制、河道内源疏浚及生态建设、污染土壤恢复、饮用水环境保护与水污染影响水源替代工程等建设项目,通过采取生态、工程和管理的综合措施,确保沘江流域水环境安全,维护沘江流域水生态系统平衡,促进该流域上游与下游、经济与环保协调发展。     

澜沧江流域矿产资源开发的环境保护对策

在澜沧江流域矿产资源开发过程中，已出现了一系列环境问题。随着流域经济的发展，污染物排放量还将不断增加，２０００年“三废”排放量将是现在的２倍左右。必须采取相应的环境保护对策，合理利用资源，减少污染，以利于经济的持续发展。     

小流域可持续发展能力的生态足迹法分析--以重庆市万州区五桥河流域为例

以三峡库区五桥河流域为例,将生态足迹理论与方法运用于小流域尺度的可持续发展研究中,采用问卷调查的数据获取方式,保守地估算了该区居民的生态足迹需求和生态足迹供给,并与其他国家(地区)作比较,分析了该区的资源利用效益.结果表明,五桥河流域人均生态足迹需求为1.020 7 hm2·人-1,而生态承载力仅为0.465 2 hm2·人-1,生态赤字达到-0.555 5 hm2·人-1;生态足迹需求及亏缺主要源于林地和草地类产品的消费;五桥河流域生态足迹赤字已经高于全球水平(-0.4 hm2·人-1),资源利用效率仅为世界平均水平的12%,该区发展呈相对不可持续状态.     

Framework and Tools for Agricultural Landscape Assessment Relating to Water Quality Protection

While many scientific studies show the influence of agricultural landscape patterns on water cycle and water quality, only a few of these have proposed scientifically based and operational methods to improve water management. Territ’eau is a framework developed to adapt agricultural landscapes to water quality protection, using components such as farmers’ fields, seminatural areas, and human infrastructures, which can act as sources, sinks, or buffers on water quality. This framework allows us to delimit active areas contributing to water quality, defined by the following three characteristics: (i) the dominant hydrological processes and their flow pathways, (ii) the characteristics of each considered pollutant, and (iii) the main landscape features. These areas are delineated by analyzing the flow connectivity from the stream to the croplands, by assessing the buffer functions of seminatural areas according to their flow pathways. Hence, this framework allows us to identify functional seminatural areas in terms of water quality and assess their limits and functions; it helps in proposing different approaches for changing agricultural landscape, acting on agricultural practices or systems, and/or conserving or rebuilding seminatural areas in controversial landscapes. Finally, it allows us to objectivize the functions of the landscape components, for adapting these components to new environmental constraints.     

Adaptive management for mitigating Cryptosporidium risk in source water: A case study in an agricultural catchment in South Australia

Water-borne pathogens such as Cryptosporidium pose a significant human health risk and catchments provide the first critical pollution ‘barrier’ in mitigating risk in drinking water supply. In this paper we apply an adaptive management framework to mitigating Cryptosporidium risk in source water using a case study of the Myponga catchment in South Australia. Firstly, we evaluated the effectiveness of past water quality management programs in relation to the adoption of practices by landholders using a socio-economic survey of land use and management in the catchment. The impact of past management on the mitigation of Cryptosporidium risk in source water was also evaluated based on analysis of water quality monitoring data. Quantitative risk assessment was used in planning the next round of management in the adaptive cycle. Specifically, a pathogen budget model was used to identify the major remaining sources of Cryptosporidium in the catchment and estimate the mitigation impact of 30 alternative catchment management scenarios. Survey results show that earlier programs have resulted in the comprehensive adoption of best management practices by dairy farmers including exclusion of stock from watercourses and effluent management from 2000 to 2007. Whilst median Cryptosporidium concentrations in source water have decreased since 2004 they remain above target levels and put pressure on other barriers to mitigate risk, particularly the treatment plant. Non-dairy calves were identified as the major remaining source of Cryptosporidium in the Myponga catchment. The restriction of watercourse access of non-dairy calves could achieve a further reduction in Cryptosporidium export to the Myponga reservoir of around 90% from current levels. The adaptive management framework applied in this study was useful in guiding learning from past management, and in analysing, planning and refocussing the next round of catchment management strategies to achieve water quality targets.     

气候变化对西苕溪流域未来洪水影响研究——Ⅰ.VIC模型评估

可变下渗能力模型VIC是基于单元网格的分布式水文模型,易于与气候模式进行耦合,从而揭示气候变化对水循环的复杂影响,为分析气候变化情景下流域洪水的响应特征提供技术支撑。作为研究工作的第一步,构建了基于5 km×5 km网格分辨率的西苕溪流域VIC径流模拟模型。利用流域出口横塘村水文观测站1990~2000年日流量观测数据并结合西苕溪流域的汇流特点,采用Dag Lohmann汇流模型进行参数率定和验证。模拟结果表明：VIC模型对西苕溪流域日、年径流量的模拟值与观测值吻合良好,率定期和验证期的多年平均年径流相对误差Er分别为077%和343%,模拟日或月流量的确定性系数和Nash Suttcliffe系数都大于075,特别是对洪水年汛期流量过程的模拟,确定性系数均大于080,模型对洪水的模拟可信性较高     

Behaviour of arsenic in forested catchments following a high-pollution period

Due to high availability of adsorption sites, forested catchments could be net sinks for pollutant arsenic both during the period of increasing and decreasing pollution. We tested this hypothesis along a north-south pollution gradient in spruce die-back affected areas of Central Europe. For two water years (2007-2008), we monitored As fluxes via spruce-canopy throughfall, open-area precipitation, and runoff in four headwater catchments (Czech Republic). Since 1980, atmospheric As inputs decreased 26 times in the north, and 13 times in the south. Arsenic export by runoff was similar to atmospheric inputs at three sites, resulting in a near-zero As mass balance. One site exhibited a net export of As (2.2 g ha⁻¹ yr⁻¹). In contrast, the preceding period (1995-2006) showed much higher As fluxes, and higher As export. Czech catchments do not serve as net sinks of atmospheric As. A considerable proportion of old industrial arsenic is flushed out of the soil.     

The development and application of water management sustainability indicators in Brazil and Scotland

This paper reports the formulation and application of a framework of catchment-level water resource management indicators designed to integrate environmental, economic and social aspects of sustainability. The framework of nine indicators was applied to the River Dee and River Sinos catchments in Scotland and Brazil, respectively, following an indicator selection process that involved inputs from water management professionals in both countries, and a pilot exercise in Scotland. The framework was found to capture a number of key sustainability concerns, and was broadly welcomed by water resource managers and experts as a means of better understanding sustainable water resource management. Issues relating to poor water quality and public water supply were particularly prominent in the findings for the Sinos, while findings for the Dee suggested that more attention might be focused on building institutional capacity and public participation in catchment management. The use of some proxy indicators was required in both catchments due to poor data availability, and this problem may hinder the further development of indicator frameworks that attempt to better integrate environmental, economic and social dimensions of sustainability.