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The Qinling Mountains are located in a transition zone between (semi)-arid regions in north China and humid regions in south China. The water resource and water ecology of regional rivers are strongly affected by climate change and human activity. In this paper, the stochastic simulation of river water regulation was performed and an optimal water regulation scheme of rubber dam projects was developed by establishing a multi-objective stochastic constraint water regulation model of rubber dam projects based on the coupling of a distributed hydrological model and a water balance model. Results show that a 40% reduction of water occurred in the lower river channel due to the operation of water supply project in the upper reach and impoundment by rubber dam projects in the lower reaches. This water reduction was associated with decreased water environment selfpurification capacity and serious deterioration of water quality for smaller ecological basic flow and mean flow velocity. By establishing a multi-objective stochastic constraint programming model, the average velocity and the ecological basic flow at different adjusting heights of rubber dams are determined. The regulation scheme of rubber dam projects we propose in this paper may optimize the current river water management strategies and help to improve the river water quality environment in urban rivers. [ABSTRACT FROM AUTHOR]

Under changing environment, the feasibility and potential impact of an inter-basin water transfer project can be evaluated by employing the coincidence probability of runoff in water sources area (WSA), water receiving area (WRA), and the downstream impacted area (DIA). Using the Han River to Wei River Water Transfer Project (HWWTP) in China as an example, this paper computed the coincidence probability and conditional probability of runoff in WSA, WRA and DIA with the copulabased multivariate joint distribution and quantified their acceptable and unfavorable encounter probabilities for evaluating the water supply risk of the water transfer project and exploring its potential impact on DIA. Results demonstrated that the most adverse encounter probability (dry-dry- dry) was 26.09%, illustrating that this adverse situation could appear about every 4 years. The acceptable and unfavorable probabilities in all encounters were 44.83 and 55.17%, respectively, that is the unfavorable situation would be dominant, implying flood and drought risk management should be paid greater attention in project operation. The conditional coincidence probability (dry WRA & dry DIA if dry WSA) was close to 70%, indicating a requirement for an emergency plan and management to deal with potential drought risk. [ABSTRACT FROM AUTHOR]

Variations in a lake area constitute an important indicator of the modifications of the lake hydrology. This paper explores the inter-annual variations of the Poyang Lake area during the dry seasons occurring within the 1961 to 2010 period and further quantifies the severity of dryness recently endured during the 2000s. A physically based hydrodynamic model of Poyang Lake established the relation between the lake area and lake level. The lake areawas calculated using the observed lake water level. Results indicated the average lake area in the dry seasons was 1,015 km2. There was a considerable inter-annual variation of the minimumlake area that varied from702.8 km2 to 1,259.7 km2. Poyang Lake experienced the most severe dryness in the 2000s, resulting in an average lake area during 2001 to 2010 of 124 km2 less than that of the preceding period. During the dry seasons, the catchment of the river discharge is likely the primary cause of the changes in lake area. This study evaluated the inter-annual variations of the Poyang Lake over a period of 50 years. Our results may provide support for an integrated management of the lake-catchment system, securing the water supply. [ABSTRACT FROM AUTHOR]

With population increase and economic growth, the flow regime of the Yangtze River has been altered to some extent by human activities, particularly dam construction. Dam-induced alterations in the flow regime of the Yangtze River will unavoidably influence water allocation among different water users and instream ecological water requirements may not be guaranteed during some months, particularly during phases of reservoir storing water. To assess the impacts of the Three Gorges reservoir operation on the downstream minimum instream ecological water requirements, this paper selected the Three Gorges reservoir and Yichang hydrological station below the reservoir as case study sites. On the basis of long-term time series of daily discharge data, the reservoir outflow was simulated under two water storing schemes and the degree to which the downstream minimum ecological flow was satisfied was computed. The results of this paper could provide references for the integrated management of the Yangtze River water resources and the assessment of dam-induced impacts on the Yangtze River ecosystem health. [ABSTRACT FROM AUTHOR]

This paper analyses the present condition of the water shortage in north China where annual rainfall is low and per capita water resource is below the line of regular water stress, or even the line of absolute water scarcity. Of the available water resources, the percentge of water withdrawal in all the north basins is high - the Yellow River and Huai River basins being greater than 80% and the Hai River basin mainly depending on interbasin water transfer. Over-withdrawal of water also results in serious water environmental problems including ‘flow cut-off’ of the Yellow River main channel and water pollution of many rivers. The paper also analyses the potential of wastewater as a resource and the demand for treated wastewater re-use. In north China, due to low rainfall and high potential evaporation environmental re-use, gardening, afforestation, etc. is considered as the main usage of the treated wastewater. Considering the economic restrictions in the less developed area, a decentralised system can be taken as an important option in formulating water re-use strategies. [ABSTRACT FROM AUTHOR]

Stakeholder involvement in drinking water supply systems is crucial for the successful management and improvement of drinking water supply systems. However, there is no agreement on stakeholders, their interests, and levels of importance, especially in drinking water supply systems. To achieve efficient stakeholder management, the first step is to understand who the major stakeholders are and what their interests, influence, and relationships are. This paper discusses the role of stakeholders in drinking water supply systems through the consideration of the results of a stakeholder analysis. The primary data were collected from interviews and questionnaires with representatives of stakeholders in Shenzhen, China. The findings indicate that water companies, governments, consumers, and polluting companies are the most important and definitive stakeholders in drinking water supply systems in China. However, their interests, attitudes, and influence on drinking water supply systems are quite different. [ABSTRACT FROM AUTHOR]

The quantity of available water resources has been recognized as the key limiting factor for development of most of the arid regions. This paper focuses on the simulation-optimization for conjunctive use of surface water and groundwater on a large scale. In this study, Hetao Irrigation District in China, one of the largest irrigation districts in the Yellow River basin, is selected as a representative study area. The conjunctive management model of water resources is developed by means of dynamically coupling a large-scale hydrological model with an optimal allocation model. A groundwater level is adopted in the coupled model as the constraint condition and the optimal conjunctive utilization quantity of surface water and groundwater is set as the objective function. Finally, the coupled model is applied to calculate the optimal water supply quantity of surface water and groundwater and sustainable utilization scheme of water resources for 2020 and 2030 in Hetao Irrigation District. The modeling results demonstrate the conjunctive management model of water resources is an effective tool for appraising water resources in large-scale arid regions. [ABSTRACT FROM AUTHOR]

Due to the surface water in the upper reaches of Yangtze River in China containing large amounts of silt and algae, high content of microorganisms and suspended solids, the water in Yangtze River cannot be used for cooling a heat pump directly. In this paper, the possibility of using Yangtze River, which goes through Chongqing, a city in southwest China, as a heat source-sink was investigated. Water temperature and quality of the Yangtze River in the Chongqing area were analyzed and the performance of water source heat pump units in different sediment concentrations, turbidity and algae material conditions were tested experimentally, and the water quality standards, in particular surface water conditions, in the Yangtze River region that adapt to energy-efficient heat pumps were also proposed. The experimental results show that the coefficient of performance heat pump falls by 3.73% to the greatest extent, and the fouling resistance of cooling water in the heat exchanger increases up to 25.6% in different water conditions. When the sediment concentration and the turbidity in the river water are no more than 100 g/m³ and 50 NTU respectively, the performance of the heat pump is better, which can be used as a suitable river water quality standard for river water source heat pumps. [ABSTRACT FROM AUTHOR]

With population increase and economic growth, the development of water resources and hydropower resources of the Hanjiang River has been intensified by dam building, and consequently the sediment regime of the Hanjiang River has been altered to some extent. To assess dam-induced alterations in the sediment regime of the Hanjiang River quantitatively, we selected three key hydrological stations (Baihe, Huangzhuang and Xiantao) as case study sites above and below the Danjiangkou reservoir respectively, and the whole study period was divided into two sub-periods according to the year when the reservoir started to store water. On the basis of time series of daily sediment data from the three stations, the alterations in their annual, seasonal, monthly and daily sediment load, and the relationships between water quantity and sediment load in different sub-periods were investigated, and the driving forces for the alterations were also explored. The output of this paper could provide reference for the assessment of the impacts of human activities on the long-term health and stability of the Hanjiang River ecosystem. [ABSTRACT FROM AUTHOR]

Spatial distribution of reference evapotranspiration (ET0) is essential in water resources planning and management, especially in semi-arid areas. In this paper, a digital elevation model is used in an `interpolate-then-calculate' approach to calculating the spatially distributed ET0 using the physically based Penman-Monteith equation in the Taoer river basin in China. The results show the following. (1) Of 11 interpolation methods, the Inverse Distance Weighting (IDW) method was found to be best for interpolating wind speed and a tn-variate secondary trend surface method was found most suitable for interpolating mean air temperature and relative humidity. Spatial modelling of the radiation environment considered the effects of elevation, slope and aspect. (2) Monthly values in January for the three meteorological variables showed larger spatial variations than in July, and just the reverse of net surface radiation. (3) The resulting ET0 calculated at each grid cell with 200m resolution and its spatial variation showed strong seasonal variation. Lower ET0 was found in high-elevation southern Great Xingan mountains in the northwest basin, while higher values were located in the plains adjacent to the lower reach. (4) The ET0 distribution by the `interpolate-then-calculate' approach better reflected the effects of topography than that of the `calculate-then-interpolate' approach. [ABSTRACT FROM AUTHOR]

This paper has compared the legal frameworks supporting water management in Europe and China, with special focus on integrated river basin management (IRBM) to identify synergies and opportunities in policymaking and implementation. The research shows that China has committed to the efficient management of water resources through various policy tools during the current period. This commitment, however, has often been interrupted and distorted by politics, resulting in the neglect of socioeconomic and environmental priorities. The European legal framework supporting water management underwent a complex and lengthy development, but with the adoption of the Water Framework Directive provides a policy model on which to develop an integrated and sustainable approach to river basin management, elements of which may help to meet the demands of the emerging 21st century Chinese society on these critical natural resources. [ABSTRACT FROM AUTHOR]

This article presents a letter from the editor, which discusses the fifth World Water Congress of the International Water Association, which was held in Beijing, China. Manuscripts submitted to the convention are discussed, which include 183 papers that were selected for publication in five issues of "Water Science and Technology," and three issues of "Water Science and Technology: Water Supply."

This article discusses the Fifth World Water Congress of the International Water Association (IWA) which was held in Beijing, China on September 10-14, 2006 and was attended by around three thousand delegates. More than a hundred papers have been selected for publication in five issues of Water Science and Technology and three issues of Water Science and Technology: Water Supply. A further group of sixty high-quality articles focusing on practitioner-oriented work have been selected and published in IWA Publishing's new online journal Water Practice and Technology (www. Iwaponline. Com/wpt). IWA's World Water Congresses provide water professionals with a forum to meet and discuss key issues of science, engineering, business and policy relating to water and the water environment.

This article discusses the Fifth World Water Congress of the International Water Association (IWA) which was held in Beijing, China on 10-14 September 2006 and was attended by around three thousand delegates. More than a hundred papers have been selected for publication in five issues of Water Science and Technology and three issues of Water Science and Technology: Water Supply. A further group of sixty high-quality articles focusing on practitioner-oriented work have been selected and published in IWA Publishing's new online journal Water Practice and Technology (www. Iwaponline. Com/wpt). IWA's World Water Congresses provide water professionals with a forum to meet and discuss key issues of science, engineering, business and policy relating to water and the water environment.

This article discusses the Fifth World Water Congress of the International Water Association (IWA) which was held in Beijing, China on 10-14 September 2006 and was attended by around three thousand delegates. More than a hundred papers have been selected for publication in five issues of Water Science and Technology and three issues of Water Science and Technology: Water Supply. A further group of sixty high-quality articles focusing on practitioner-oriented work have been selected and published in IWA Publishing's new online journal Water Practice and Technology (www. Iwaponline. Com/wpt). IWA's World Water Congresses provide water professionals with a forum to meet and discuss key issues of science, engineering, business and policy relating to water and the water environment.