Impacts of the North Atlantic Oscillation on Scandinavian Hydropower Production and Energy Markets

Dramatic swings in the North Atlantic oscillation (NAO) during the 1990s motivated the authors to build a statistical model of NAO impacts on hydropower production and energy markets in Scandinavia. Variation in the NAO index is shown to explain 55% of the variance of streamflow in Norway and up to 30% of the variance in Norway's hydropower output. It is also possible to identify the influence of NAO anomalies on electricity consumption and prices. Government liberalization allowed a financial market to grow around the international trading of electricity, which in Norway is produced almost entirely from hydropower. The model offers a possible tool for predicting the effects of future NAO movements on hydropower production and energy prices in Scandinavia. The potential influence of skillful climate prediction is discussed.     

近50年中国不同气候区典型流域降雨径流变化趋势

应用近50年中国4个不同气候区典型流域重点控制站的降雨、径流观测资料,采用线性回归法和M-K检验法分别分析了各个流域的降雨、径流量变化情况。结果表明,南方湿润气候区石角站以上流域的降雨、径流量均表现出了增加的趋势,而处于其他气候区典型流域的降雨及径流量呈现出了下降的趋势,特别是处于半湿润半干旱气候区的邢家窝棚站以上流域的降雨、径流下降趋势明显,这严重影响了我国经济社会的发展。     

Colonization of the Laurentian Great Lakes by the Amphipod Gammarus tigrinus,a Native of the North American Atlantic Coast

Gammarus tigrinus, whose natural distribution is restricted to the North American Atlantic coast, has been found at numerous localities across the Laurentian Great Lakes. This amphipod was first discovered in Saginaw Bay of Lake Huron in 2002. However, analysis of archived samples and new material collected during 2001–2004 revealed that G. tigrinus is present in all of the Great Lakes. During August 2002, it occurred at an average density of 283 individuals·m⁻² in Saginaw Bay, where it was outnumbered by the resident amphipods G. fasciatus and Hyalella azteca. In terms of frequency of occurrence, G. tigrinus was the second most numerous amphipod in beds of Typha in lower Great Lakes coastal wetlands during July 2004, being outnumbered only by native G. pseudolimnaeus. Gammarus tigrinus has a history of ballast water transfer in Europe and it likely exploited this transport vector during its recent colonization of the Great Lakes.     

Risk-Based Assessment of Drought Mitigation Options: the Case of Syros Island,Greece

Drought-related risk estimation is widely acknowledged as a tool towards enhancing drought preparedness and minimizing impacts on people, the economy and the environment. In this paper a method is proposed for the risk-based assessment and prioritisation of long-term drought mitigation options in order to support decision making for drought planning. The assessment combines water balance modelling, hazard analysis, and risk and cost effectiveness analysis. The proposed approach allows an improved understanding of drought-related risks by following a probabilistic analysis of drought impacts under different mitigation options. The method is applied in a drought-prone area with water scarcity problems, the Greek island of Syros. The assessment focuses on agriculture and domestic water use, the two main water using sectors in the island. Six mitigation options are cross-compared in terms of contribution to future drought risk reduction using three criteria: risk, vulnerability and benefit-cost ratio. The results validate the use of risk-based assessment of mitigation options as a valuable tool for improved drought management.     

温家宝副总理视察南水北调工程北京段

中共中央政治局委员、国务院副总理温家宝于5月11日视察了南水北调工程北京段,在现场听取了工程介绍,主持召开了汇报会,发表了重要讲话。水利部部长汪恕诚等国务院有关部门负责人陪同视察,北京市市长刘淇等领导参加了视察和汇报。     

关于南水北调西线工程资本运作模式的思考

南水北调西线工程是国家的一项大型跨流域的重大水利和环境保护工程，投资巨大，如何进行西线工程的资本运作是工程建设中的关键问题。本文从西线工程的性质分析了如何进行工程资本运作的几种模式，探讨了在我国现行货币政策和金融体系下的工程资本融资，提出了建立国资公司、发行市政债券或企业债券和银行贷款模式的思考，供商榷。     

Relating Trends in Streamflow to Anthropogenic Influences: A Case Study of Himayat Sagar Catchment,India

Catchment development has been identified as a potentially major cause of streamflow change in many river basins in India. This research aims to understand changes in the Himayat Sagar catchment (HSC), India, where significant reductions in streamflow have been observed. Rainfall and streamflow trend analysis for 1980–2004 shows a decline in streamflow without significant changes in rainfall. A regression model was used to quantify changes in the rainfall-runoff relationship over the study period. We relate these streamflow trends to anthropogenic changes in land use, groundwater abstraction and watershed development that lead to increased ET (Evapotranspiration) in the catchment. Streamflow has declined at a rate of 3.6 mm/y. Various estimates of changes in evapotranspiration/irrigation water use were made. Well inventories suggested an increase of 7.2 mm/y in groundwater extractions whereas typical irrigation practices suggests applied water increased by 9.0 mm/y, while estimates of evapotranspiration using remote sensing data showed an increasing rate of 4.1 mm/y. Surface water storage capacity of various small watershed development structures increased by 2 mm over 7 years. It is concluded that the dominant hydrological process responsible for streamflow reduction is the increase in evapotranspiration associated with irrigation development, however, most of the anthropogenic changes examined are interrelated and occurred simultaneously, making separating out individual impacts very difficult.     

雨水情自动遥测系统在防汛测报中的应用

对雨水情遥测处理系统在泰安市防汛测报中的应用进行了分析,结果表明：该系统取代了近50年来的人工信息采集和手工报汛,大大提高了防汛信息采集传递的时效性、准确性、决策性;系统工作稳定、安全可靠,节省了大量的人力、物力和财力;实现了雨水情信息的自动化、规范化和现代化;推广应用前景广阔。     

浅谈崇明岛河道整治中生态护岸的应用

生态护岸是现代河道整治的发展趋势,该文结合崇明岛作为生态岛的定位,着重介绍了石笼护岸及绿化混凝土护岸两种生态护岸的设计应用。     

关于南水北调有关管理问题的思考

该文阐述南水北调调水后的科学管理，合理地处理好上游与下游、外调水与本地水、清水与污水、直供与蓄供、统一管理与分级管理等各种关系问题。     

Application of Multinomial Logistic Regression to Model the Impact of Rainfall Genesis on the Performance of Storm Overflows: Case Study

Water Resources Management - In this study, a mathematical model was proposed to analyze the performance of storm overflows. The model included the influence of rainfall genesis on the duration of...     

Mobility of contaminants in relation to dredging operations in a mesotidal estuary (Tagus Estuary,Portugal)

During the construction of a New Bridge over the Tagus estuary 2.5 million tons of sediments were dredged, part of this quantity being contaminated material. The extension and intensity of the water turbidity associated with dredging operating varied with the tidal conditions but the resuspended material collected near the bucket dredger did not present a concnetration increment in metals and PCB, when compared to the estuarine suspended sediments. The calculated distribution coefficients suggest that some contaminants in solids near the dredger were not in equilibrium with the water. A 24-hour laboratory experiment demonstrated the complexity and quickness of anoxic sediments oxidation. In such a short period of time metals in the solids change their fractionation. A second laboratory simulation showed that mussels accumulate metals and PCB congeners when placed in turbid aerated water.     

A groundwater perspective on the river basin management plan for central Portugal - developing a methodology to assess the potential impact of N fertilizers on groundwater bodies

The Water Framework Directive establishes that the river basin management plans must have a summary of the pressures and impacts of human activities, such as agriculture, on the chemical and quantitative status of groundwater bodies. In order to identify those areas where a potential impact from agricultural activities on groundwater bodies exists, but currently lacking groundwater monitoring data, a methodology was developed that combines the use of gross nitrogen balance values with the results of a specific vulnerability assessment index. A farm management efficiency parameter is added, to identify the factors that contribute to nitrogen use efficiency and to assess the near-future scenarios. This methodology allows the identification of significant pressures that may be responsible for a groundwater body failing good status where there is no representative monitoring network.     

中小型水电站蜗壳外围钢筋混凝土结构简化计算

水电站厂房下部结构蜗壳的外围混凝土结构几何形状不规则,内部应力也较复杂。内力分析时,结构可近似简化为平面框架计算,计算结果较可靠,设计效率可大大提高。     

南水北调中线京石段隧洞工程设计浅议

南水北调中线工程属特大型远距离跨流域调水工程,其工程等别为一等,主要建筑物为1级建筑物。南水北调中线京石段内共设置7座隧洞,隧洞总长为9642m,其中隧洞洞身长8626m,其共同的特点是：长距离、大流量、低水头。设计中创造性地提出了一些新观点,如通过采用双洞线布置、合理降低进口底高程、减糙混凝土的应用、进出口涵洞段的布置等措施,提高了总干渠的输水保证率,节约了投资,节省了水头,提高了工程的安全度,并为以后类似工程提供参考。     

南水北调东线调水对长江河口水资源的影响

根据长江河口区水文水资源勘测资料,分析了长江河口区水流变化、盐水入侵的现状及其基本规律.认为南水北调东线工程实施后,丰水年与常水年对长江河口水资源无明显影响;枯水年的枯水期,即使限制抽江流量,对河口淡水量也会有一定影响;工程建成运行后潮流界将上移约3 km,盐水入侵长度有所增加,其增加幅度小于潮流量上移幅度,即小于3 km.为此,应尽早进行系统监测、研究,在进一步弄清基本资料的基础上,提出工程优化调度的工程和非工程对策与措施,以趋利避患.     

Anthropogenic and climatic influences over the past three centuries on characteristics of an Adirondack lake,Eastern North America

Fourth Lake is a drainage lake at 43°N, 74°W, from which a 37‐cm long mud‐water interface core was recovered. ²¹⁰Pb dating indicates the core spans ≈340 years, from the Little Ice Age through modern global warming. Diatom accumulation responds to anthropogenic watershed disturbances, declining slightly up‐core until a peak in the late‐1800s attributable to sediment and nutrient influx from logging and enlargement of the outlet dam. A dramatic decrease occurs ≈1900 as logging and lake filling ceased, and a smaller peak ≈1960 accompanies residential development. Similar changes occur in organic carbon accumulation, which ranges from 0.0038–0.024 mg cm^?2 year^?1, with generally decreasing values up‐core, punctuated by maximum values in the late‐1800s. Expressing diatoms as concentration, however, reveals a doubling up‐core that positively correlates with changes extending beyond the watershed, including Northern Hemisphere temperature, atmospheric CO₂ concentration and solar irradiance (R = 0.627, 0.675 and 0.400, respectively). A >50% increase in % organic carbon, from 3.8% to 5.9%, also positively correlates with these larger‐scale environmental conditions (R = 0.828, 0.830 and 0.832), while negative correlations with the extrabasinal records are exhibited by magnetic susceptibility (R = ?0.654, ?0.496, and ?0.660) and clay (R = ?0.770, ?0.762, and ?0.737). These changes are consistent with decreased sediment influx and reduced dilution of biogenous sedimentary components. In contrast to total diatoms, the accumulation of planktonic genus Asterionella displays a long‐term increase up‐core. Potential explanations include increasing duration of the ice‐free season or a shift in the timing of the spring bloom and a mismatch with abundance of predator(s). Asterionella also increases as a percentage of total diatoms, being positively correlated with extrabasinal conditions (R = 0.827, 0.774 and 0.674). This change occurs at the expense of many benthic genera and, over the past century, at the expense of tychoplanktonic genus, Aulacosiera. Heavily silicified, Aulacosiera requires strong mixing to remain within the epilimnion. Thus, its decline might result from increasing stratification caused by warming.     

Application of Monte Carlo Simulation Technique to Design Flood Estimation: A Case Study for North Johnstone River in Queensland, Australia

The traditional rainfall-runoff modelling based on the Design Event Approach has some serious limitations as this ignores the probabilistic nature of the key flood producing variables in the modelling except for rainfall depth. A more holistic approach of design flood estimation such as the Joint Probability Approach/Monte Carlo simulation can overcome some of the limitations associated with the Design Event Approach. The Monte Carlo simulation technique is based on the principle that flood producing variables are random variables instead of fixed values. This allows accounting for the inherent variability in the flood producing variables in the rainfall-runoff modelling. This paper applies the Monte Carlo simulation technique and hydrologic model URBS to a large catchment with multiple pluviograph and stream gauging stations. It has been found that it is quite feasible to apply the Monte Carlo simulation technique to large catchments. The Monte Carlo simulation technique has much greater flexibility than the Design Event approach and can provide more realistic design flood estimates with multiple scenarios, which is likely to replace the Design Event Approach. The method developed here can be applied to other catchments in Australia and other countries.     

Drought Forecasting Using Neural Networks,Wavelet Neural Networks,and Stochastic Models: Case of the Algerois Basin in North Algeria

Drought forecasting is a major component of a drought preparedness and mitigation plan. This paper focuses on an investigation of artificial neural networks (ANN) models for drought forecasting in the algerois basin in Algeria in comparison with traditional stochastic models (ARIMA and SARIMA models). A wavelet pre-processing of input data (wavelet neural networks WANN) was used to improve the accuracy of ANN models for drought forecasting. The standard precipitation index (SPI), at three time scales (SPI-3, SPI-6 and SPI-12), was used as drought quantifying parameter for its multiple advantages. A number of different ANN and WANN models for all SPI have been tested. Moreover, the performance of WANN models was investigated using several mother wavelets including Haar wavelet (db1) and 16 daubechies wavelets (dbn, n varying between 2 and 17). The forecast results of all models were compared using three performance measures (NSE, RMSE and MAE). A comparison has been done between observed data and predictions, the results of this study indicate that the coupled wavelet neural network (WANN) models were the best models for drought forecasting for all SPI time series and over lead times varying between 1 and 6 months. The structure of the model was simplified in the WANN models, which makes them very convenient and parsimonious. The final forecasting models can be utilized for drought early warning.

     

广东:安全为本狠抓落实努力推动小水电管理上新水平

近年来,围绕小水电安全管理问题,广东省相继开展了违规小水电站清理整顿、小水电站安全核查和分类定级、隐患小水电站整治、小水电站年检以及安全管理长效机制建设等工作,并取得了较好成效.全省小水电站没有因为工程问题而出现重大事故,经受住了台风暴雨的严峻考验,有效地保护了人民群众的生命财产安全.