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Guan C.M.,Beijing Institute of Water
Applied Mechanics and Materials | Year: 2014

The project of substituting small hydropower for fuel (SHPF project in short) in China has been implemented for ten years and has achieved significant economic, social and ecological benefits. The construction, completion situations, results and major experience of the SHPF project are summarized. The existing problems are analyzed. Some suggestions are given for the construction and management of similar projects in future. © (2014) Trans Tech Publications, Switzerland. Source

Wang F.,Shanghai University | Wang B.,Chinese Academy of science | Liu C.-Q.,Chinese Academy of science | Wang Y.,Beijing Institute of Water | And 2 more authors.
Atmospheric Environment | Year: 2011

Recently, controversies about whether hydropower is still a clean energy have been arisen up with the studies about high CO2 emission flux from hydroelectric reservoirs in boreal and tropical regions. In this study, four subtropical reservoirs and their related reaches, draining on karstic area in southwest of China, were investigated to understand their CO2 emission, with monthly sampling strategy from July 2007 to June 2008. pCO2 values in the surface water of these reservoirs ranged from 38 to 3300 μ atm, indicating that reservoir surface could be not only source but also sink to atmosphere CO2 in different seasons. In Hongfeng reservoir, the flux of CO2 from surface water varied from -9 to 70 mmol m-2 d-2 with an average of 15 mmol m-2 d-2, and in Baihua reservoir, it had a range from -8 to 77 mmol m-2 d-2 with an average of 24 mmol m-2 d-2. Hongyan reservoir had similar average flux of CO2 to Baihua reservoir. Xiuwen had the highest average flux of CO2 with a value of 47 mmol m-2 d-2 among the studied reservoirs. Downstream the dams discharged by hydropower generation from these reservoirs generally had quite high flux of CO2, with an average of 489 ± 297 mmol m-2 d-2, which is close to those from tropical rivers. This means that water releasing from these reservoirs would be an important way for CO2 emission into atmosphere. The results showed that dam construction has significant impacts on the river water chemistry, with abrupt changes in pCO2, DO, T, pH and SIc in surface water and their outlets. In addition, with the development of thermal gradient in warm seasons, water chemistry along the water column of reservoirs also showed seasonal variations, except in Xiuwen reservoir which only has daily storage capacity. © 2011 Elsevier Ltd. Source

Huang J.,CAS Nanjing Institute of Geography and Limnology | Gao J.,CAS Nanjing Institute of Geography and Limnology | Liu J.,Beijing Institute of Water | Zhang Y.,China National Environmental Monitoring Center
Ecological Modelling | Year: 2013

Kalman filter has been successfully used in assimilating observations into the existing models, and has been continually adjusted for its wider use. In this study, one of the Kalman filter techniques (ensemble Kalman filter) was used to assimilate measured data into a spatial hydrodynamic-phytoplankton model for predicting dynamics of phytoplankton biomass in Lake Taihu. In order to investigate the effects of the initial conditions (chlorophyll a) and the model parameter on the model fit, we carried out three simulations with different update strategies of parameter and variable using ensemble Kalman filter. Two simulations updated both of model parameter and state variable once and twice a week, respectively. Another simulation updated the state variable once a week, respectively. The simulation results show that the model fit was improved when the state variable (chlorophyll a) was updated by measured data in a shorter term, and was slightly improved with time-varying parameter. In this respect, good estimates of initial chlorophyll a conditions are critical to achieve good predictions of chlorophyll a dynamics in Lake Taihu. This study demonstrates the success of the ensemble Kalman filter technique in improving models' predictive skill, and implementing time-varying parameters for ecological models. © 2013 Elsevier B.V. Source

Hu C.,Beijing Institute of Water
Shuili Xuebao/Journal of Hydraulic Engineering | Year: 2016

Sediment deposition in a reservoir constructed in a sediment-laden river has a direct impact on the reservoir's lifespan and its comprehensive benefits of flood control, power generation, navigation and water supply. In 1970s the reservoir operation mode of 'Storing Clear Water and Discharging Muddy Flow' was put forward by Chinese scientists for coping with serious sedimentation problem in the Sanmenxia Reservoir, and further applied and developed in several key water control projects such as the Xiaolangdi Reservoir on the Yellow River and the Three Gorges Reservoir on the Yangtze River. This operation mode successfully solves the problem of the conflict between sedimentation and benefits of a reservoir on a sediment-laden river by reducing its sediment deposition and maintaining its effective storage capacity for long-term use. It gives full play to the comprehensive benefits of a reservoir and presents an effective new way to cope with reservoir sediment problem for a sediment-laden river. The operation mode of 'Storing Clear Water and Discharging Muddy Flow' will be constantly optimized and improved in practice along with the knowledge deepening on reservoir sediment problems. Base on the actual situation of changes on runoff and sediment loads of rivers, the paper puts forward suggestions on further optimizing operation mode for the Three Gorges Reservoir and Xiaolangdi Reservoir to ensure the projects'safety and comprehensive benefits and to provide scientific support for promoting development on the theory and technology of reservoir sedimentation. © 2016, China Water Power Press. All right reserved. Source

Yang X.H.,Beijing Normal University | Zhang X.J.,Beijing Normal University | Hu X.X.,Beijing Normal University | Yang Z.F.,Beijing Normal University | Li J.Q.,Beijing Institute of Water
Nonlinear Processes in Geophysics | Year: 2011

There is much uncertain information which is very difficult to quantify in the water resource renewability assessment (WRRA). The index weights are the key parameters in the assessment model. To assess the water resource renewability rationally, a novel nonlinear optimization set pair analysis model (NOSPAM) is proposed, in which a nonlinear optimization model based on gray-encoded hybrid accelerating genetic algorithm is given to determine the weights by optimizing subjective and objective information, as well as an improved set pair analysis model based on the connection degree is established to deal with certain-uncertain information. In addition, a new calculating formula is established for determining certain-uncertain information quantity in NOSPAM. NOSPAM is used to assess the water resource renewability of the nine administrative divisions in the Yellow River Basin. Results show that NOSPAM can deal with the uncertain information, subjective and objective information. Compared with other nonlinear assessment methods (such as the gray associate analysis method and fuzzy assessment method), the advantage of NOSPAM is that it can not only rationally determine the index weights, but also measure the uncertain information quantity in the WRRA. This NOSPAM model is an extension to nonlinear assessment models. © Author(s) 2011. Source

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