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Zhou J.,Huazhong University of Science and Technology | Song L.,Huazhong University of Science and Technology | Song L.,Pearl River Hydraulic Research Institute | Kursan S.,Hrvatske Vode Legal Entity for Water Management | Liu Y.,Huazhong University of Science and Technology
Environmental Research

A two-dimensional coupled water quality model is developed for modeling the flow-mass transport in shallow water. To simulate shallow flows on complex topography with wetting and drying, an unstructured grid, well-balanced, finite volume algorithm is proposed for numerical resolution of a modified formulation of two-dimensional shallow water equations. The slope-limited linear reconstruction method is used to achieve second-order accuracy in space. The algorithm adopts a HLLC-based integrated solver to compute the flow and mass transport fluxes simultaneously, and uses Hancock's predictor-corrector scheme for efficient time stepping as well as second-order temporal accuracy. The continuity and momentum equations are updated in both wet and dry cells. A new hybrid method, which can preserve the well-balanced property of the algorithm for simulations involving flooding and recession, is proposed for bed slope terms approximation. The effectiveness and robustness of the proposed algorithm are validated by the reasonable good agreement between numerical and reference results of several benchmark test cases. Results show that the proposed coupled flow-mass transport model can simulate complex flows and mass transport in shallow water. © 2015 Elsevier Inc. Source

Zhou J.,Huazhong University of Science and Technology | Zhao Y.,Huazhong University of Science and Technology | Song L.,Pearl River Hydraulic Research Institute | Bi S.,Huazhong University of Science and Technology | Zhang H.,Huazhong University of Science and Technology
Ecological Informatics

The Chinese sturgeon (Acipenser sinensis), a kind of maricolous anadromous migratory fish species, is endangered and protected in China. Historical spawning habitats were distributed in the lower reaches of Jinsha River and the upper reaches of Yangtze River. Since the establishment of the Gezhouba water conservancy pivot in 1981, the migratory route of Chinese sturgeon spawning was blocked. Therefore, the fish was forced to propagate in a new spawning ground which was mainly distributed in the 4-km-long mainstream from Gezhouba Dam to Miaozui in the middle Yangtze River. After water storage and power generation of the Three Gorges reservoir (TGR) in 2003, the propagation of Chinese sturgeon has been impacted gradually. According to field surveys, the fish used to spawn twice a year before TGR impoundment, but only once happened after that. Besides, the spawning scale is also declining with each passing year.In order to simulate and evaluate the effect of TGR impoundment on spawning habitats of Chinese sturgeon, with consideration of their reproductive characteristics, an eco-hydrodynamic model was established by coupling a two-dimensional hydrodynamic model and a fuzzy fish habitat module based on fuzzy logic inference. Flow fields at the studied site in an impoundment scenario and an assumed no impoundment scenario were simulated with the 2D hydrodynamic model. Afterwards, by linking hydrodynamic conditions to the expert knowledge base, the fuzzy habitat model used fuzzy logic inference to compute habitat suitability of the Chinese sturgeon. In addition, the approach was used to propose a suitable instream flow range during the propagation period for Chinese sturgeon. The results indicated that the suitable instream flow needed for Chinese sturgeon spawning in middle Yangtze River should be between 10,000m3/s and 17,000m3/s and it also showed that after TGR was put into pilot impoundment operation at the designed water level of 175m, the habitat suitability has decreased significantly in October. Besides, the water temperature of spawning habitat increased to a higher level in propagation period due to the impoundment of the TGR. All these alterations have had imposed tremendous impacts on the propagation of Chinese sturgeon. Therefore, adjusting impoundment schedule of the TGR to recover the water flow over spawning habitat in October is a crucial way to improve the habitat suitability. Furthermore, the presented method also provides a theoretical basis for further research on the assessment of habitat suitability of aquatic species at a micro-habitat scale. © 2014 Elsevier B.V. Source

Liu B.,Sun Yat Sen University | Chen J.,Sun Yat Sen University | Chen X.,Sun Yat Sen University | Lian Y.,University of Illinois at Urbana - Champaign | Wu L.,Pearl River Hydraulic Research Institute
Journal of Hydrology

Extreme precipitation events are rare and occur mostly on a relatively small and local scale, which makes it difficult to set the thresholds for extreme precipitations in a large basin. Based on the long term daily precipitation data from 62 observation stations in the Pearl River Basin, this study has assessed the applicability of the non-parametric, parametric, and the detrended fluctuation analysis (DFA) methods in determining extreme precipitation threshold (EPT) and the certainty to EPTs from each method. Analyses from this study show the non-parametric absolute critical value method is easy to use, but unable to reflect the difference of spatial rainfall distribution. The non-parametric percentile method can account for the spatial distribution feature of precipitation, but the problem with this method is that the threshold value is sensitive to the size of rainfall data series and is subjected to the selection of a percentile thus make it difficult to determine reasonable threshold values for a large basin. The parametric method can provide the most apt description of extreme precipitations by fitting extreme precipitation distributions with probability distribution functions; however, selections of probability distribution functions, the goodness-of-fit tests, and the size of the rainfall data series can greatly affect the fitting accuracy. In contrast to the non-parametric and the parametric methods which are unable to provide information for EPTs with certainty, the DFA method although involving complicated computational processes has proven to be the most appropriate method that is able to provide a unique set of EPTs for a large basin with uneven spatio-temporal precipitation distribution. The consistency between the spatial distribution of DFA-based thresholds with the annual average precipitation, the coefficient of variation (CV), and the coefficient of skewness (CS) for the daily precipitation further proves that EPTs determined by the DFA method are more reasonable and applicable for the Pearl River Basin. © 2013 Elsevier B.V. Source

Yang G.,China Institute of Water Resources and Hydropower Research | Yang G.,South China University of Technology | Li D.,China Institute of Water Resources and Hydropower Research | Guan D.,Pearl River Hydraulic Research Institute
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering

The tangent modulus method of undisturbed soil is used to calculate the nonlinear settlements of soil foundation and pile foundation separately; and the nonlinear relation P-S (load-settlement) curves of the soil foundation and pile foundation are obtained. Supposing that the soil foundation and pile foundation are acted independently, simultaneously considering that the settlements of soil foundation and pile foundation are equal, then we can obtain the load acting on the soil and pile by the P-S curves. Then, by controlling the settlement value and adjusting the thickness of cushion, the relative stiffnesses of soil and piles can be matched to make the best use of the bearing capacities of soil and pile foundation; and the settlement of the composite foundation can reach the desired aim. Consequently, the design of combination foundation can reach the perfect optimized condition. Finally, the implementation process of the method is explained by the case study. Source

Ying M.,North China University of Water Conservancy and Electric Power | Hehai X.,Pearl River Hydraulic Research Institute | Tianyu Z.,Tsinghua University
Nature Environment and Pollution Technology

With the development of urbanization and the improvement of the people's living standards, the contradiction against water supply and water demand is becoming more and more serious. And the development of the economy led to serious pollution of water, so it is essential to understand the water quality. This paper discussed the choice of the evaluated factors, the operations of the weight value, and compares with the status of the water quality in course of the evaluation. The conclusions indicated that the result of the fuzzy mathematics evaluation represented the water quality of surface waters. The evaluation result was compared with that of the traditional method and the reported results. It is indicated that the performance of the proposed model is practically feasible in the application of water quality assessment and its application is simple. Source

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