Modelling of N-movements on catchment scale - a tool for analysis and decision making

The modelling system described by Styczen and Storm (1993) simulates nitrogen transformation as well as water and nitrogen transport on a regional scale and can be used to evaluate effects of changes in the land use or in agricultural practices on the water quality in the groundwater and in the streams. It may be used to evaluate variations in time and space, and to predict the time lag from new strategies are implemented until measurable results are obtained. A case study was carried out on the 425 km² large Karup River catchment in Denmark for the period 1968–88, and the paper presents the data required to set up the model and results from the simulations. Most of the data and information required could be extracted from existing databases, reports, and statistical yearbooks while information on changes in management practices came from local agricultural advisers. The simulations are compared to measurements in part of the Karup River catchment.     

Integrated Catchment Modelling as a Water Resources Management Tool

Groundwater models are becoming increasingly important in water resources management. Most aquifers in the UK are closely linked with river systems, to which they contribute baseflow from seepages and springs. As a result, major groundwater abstractions almost inevitably affect river flows. To assess with confidence the effect of utilizing ground-water resources, an aquifer and river system has to be linked within an integrated model which can simulate varying hydrogeological conditions throughout the catchment.
The main features of an integrated catchment management model, which links aquifer and river systems, are described in this paper. The model has been applied to a number of catchments in southern England including the River Darent in Kent, which is probably the most well-known and worst-affected of all rivers identified nationally as suffering from over-abstraction.
The process of model preparation and calibration is illustrated with reference to the River Darent. Twenty years of river flow and groundwater hydrograph records were used in producing a close simulation of modelled and actual hydrological conditions. The model was then operated to assess a large number of possible options for restoring flows to the river. Examples of various management strategy simulations are given, leading to formulation of a water resources management plan for the Darent. This involved (a) reductions in selected abstractions, (b) flow augmentation using river support boreholes, and (c) meeting peak groundwater supply demands in drought periods.     

城市集雨工程--防水技术又一用武之地

介绍了发达国家城市雨水收集利用方面采取的措施，分析了我国城市雨水收集利用的现状、潜力和紧迫性及应采取的措施，指出我国将要开展的城市集雨工程将为防水技术提供新的用武之地。     

含大规模屋顶光伏电站接入农村配电网多目标优化配置方法

针对大规模屋顶光伏电站接入农村配电网无序分布带来的分布式发电资源浪费等问题,本文以屋顶光伏电站建设投资成本最小化和系统网络损耗最小化为优化目标,综合考虑农村地区安装面积限制和配电网运行约束,构建了含大规模屋顶光伏电站接入农村配电网多目标优化配置模型,采用针对高维度解改进的带精英策略的非支配排序算法(NSGA-II)对配置模型进行优化,针对算法求解得到的Pareto解集,应用模糊贴近度进行筛选,得出最优方案。通过IEEE-33节点配电系统算例仿真分析,结果表明：所提出的配置方法可以在提高屋顶光伏电站投资经济性的同时,利用屋顶光伏电站的优化配置提高系统的供电可靠性。     

Microbial quality of water in Barekese reservoir and feeder streams in Ghana

Concern is growing in Ghana about the high incidence of water‐related diseases and deaths resulting from use of water contaminated with microorganisms. This water often remains unsafe for human consumption because of inadequate decontamination of microbially infected water. Data are presented in this study on the microbial quality of Barekese reservoir, which is the main drinking water reservoir for the city of Kumasi and its environs (population = 2, 5 million), and nine feeder streams in its catchment. Water samples were collected from 13 sampling sites and analysed for Escherichia coli, total and faecal coliforms. Furthermore, 18 faecal coliform isolates were randomly selected from all sampling sites and confirmed as E. coli using Analytical Profile Index 20E system. Escherichia coli, total and faecal coliforms were enumerated using the most probable number method. Mean bacterial indicator numbers from all sampling sites ranged from 1.45 × 10⁴ to 9.50 × 10⁷ 100 mL^?1 for total coliforms, 1.60 × 10³ to 9.00 × 10⁵ 100 mL^?1 for faecal coliforms and 1.50 × 10¹ to 9.50 × 10³ 100 mL^?1 for E. coli. Indicator numbers exceeded the World Health Organization (0.100 mL^?1) for E. coli and Ghana Water Resources Commission‐Target Water Quality Range of 5–100 100 mL^?1 for total coliforms and 0.100 mL^?1 for faecal coliforms in water used for domestic purposes. The identified isolates in Barekese Reservoir and its feeder streams belonged to Serratia, Enterobacter, Citrobacter, Salmonella and Klebsiella genera. Bacterial numbers were significantly (P < 0.05) higher in the feeder streams, compared with Barekese Reservoir water. This finding indicates the feeder streams pose health risks to local communities that withdraw water from them. The results of this study highlight the urgent need to raise public awareness on the adverse effects of water‐quality degradation through improper waste disposal methods in order to decrease the cost of treating the reservoir water.     

Implementing the requirements of the Water Framework Directive for rural water supply schemes in Scotland

In a project pioneering the implementation of the European Union Water Framework Directive in Scotland, a programme of local stream flow gauging in Lochaber demonstrated that low flow yields in the sources were greater than predicted by standard methodologies for ungauged catchments in the UK. This meant that the abstraction required for the water treatment works represented an acceptable proportion of the yield, and complied with Scottish Environment Protection Agency guidance for maintaining good ecological status in the catchments. Development of new sources with dams, pumping stations and pipelines was avoided, thus reducing costs and environmental impacts. A programme of stakeholder consultations was carried out throughout the Water Order application process and agreement on proposed abstractions was reached with over 20 stakeholders.     

基于Matlab与VB混合编程的流域降水预报系统

利用研究区获得的水文观测资料,采用模块开发和系统集成方式,研制了研究区流域降水预报系统。介绍了系统的体系结构、主要功能、运行情况及开发的关键技术。叙述了流域降水预报的各种预报方法,并建立了基于遗传算法的降水预报神经网络模型（GA-BP网络模型）。结果表明,GA-BP网络是一种精度较高的降水预报模型,提高预测精度,增长有效预见期。该系统能根据流域观测数据、高空数据、卫星云图、数值产品等数据,实现不同数据源的信息处理和不同时效的降水预报制作,为洪水预警预报和防洪决策服务。     

存量更新背景下综合公园-周边社区 步行可达性评估及微更新分析——以 石家庄市长安公园为例

城市中心区的综合公园是提升周边社区生活品质的关键场所,也是城市生态和文化基础设施的重要节点。步行可达性对综合公园的日常使用至关重要,也是理解其潜在供需及周边中小绿地级配合理性的途径之一。直观、尽量精确且顾及尺度层级的步行范围评估有助于理解公园-社区可达性,并为确定具体干预位置和策略提供参考。以石家庄市长安公园为例,首先使用泰森多边形工具划分综合公园就近服务范围,然后抓取范围内所有住宅建筑至综合公园入口的百度地图规划路径,并根据不同距离阈值划分步行范围,发现综合公园周边的社区之间存在显著的空间差异。研究结果表明：在距离长安公园1 500m步行范围内,居民人口达14.28万人,占长安公园就近服务范围居民总人口的65.7%;周边中小绿地可以补偿服务4.58万人,但仍有2.88万居民位于合理的步行距离外。建议结合微更新理念,增设或调整公园和小区入口等以扩大现有综合公园的有效服务范围,在服务盲区内增建中小绿地以增加受惠居民的数量。     

雨强和土地利用对豫西南山区氮磷流失的影响

为了掌握雨强和土地利用方式对丹江口水库水源区养分流失的影响,通过室内人工模拟降雨试验,对从豫西南山区采集的5种常见土地利用类型的表层土壤,开展了6种雨强下TN(总氮)、TP(总磷)的流失规律研究。结果表明:1地表产流中,雨强对TN的平均含量影响显著,雨强大于1.0 mm/min时才会对TP的含量产生影响;不同用地产生的泥沙中,雨强大于等于3.0 mm/min时才会对TN、TP的含量产生显著影响。2土地类型对TN、TP的流失量也有极大的影响,乔木林、灌草地因其具有较坡耕地、梯田与荒草地更好的土壤结构,TN、TP的流失量相对较少,但前两者之间与后三者之间的差异不大。3对径流中TN、TP的含量与雨强作回归分析,除乔木林地和灌草地略有不同外,其他各用地类均为对数拟合的效果最差,多项式拟合的决定系数较高;不同用地产沙中TN、TP含量与雨强的关系,均以多项式拟合的效果为最好。     

Towards better water security in North China

Water shortages and related environmental degradation in North China are major issues facing the country. As runoff from the mountainous parts of the region steadily decrease and water resources become overcommitted, serious water and environmental problems have resulted. These include drying-up of rivers, decline in groundwater levels, degradation of lakes and wetlands, and water pollution. Thus, 4000,km of the lower reaches of the Hai River – some 40% of its length – has experienced zero flows and, as result, parts of this river have become an ephemeral stream. The area of wetland within the Basin has decreased from 10,000,km² at the beginning of 1950s to 1,000km² at present. Over-extraction of groundwater occurs beneath 70% of the North China Plain, with the total groundwater over-extraction estimated at 90,billion m³. Thus, problems of water shortage and related environmental issues in North China have become the most significant limiting factors affecting sustainable development in this important region of China. This paper addresses the water security issues facing North China in the 21st Century using the Hai River basin as an example. We describe hydrologic cycles under changing environments, water-saving agriculture, assessment of water resource security, and efforts towards achieving integrated catchment management.