Su H.,Hohai University |
Su H.,State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering |
Wen Z.,Nanjing Institute of Technology |
Wu Z.,Hohai University
Water Resources Management | Year: 2011
With systems engineering and artificial intelligent methods, an early-warning system of dam health (EWSDH) is developed. This system consists of integration control module, intelligent inference engine (IIE), support base cluster, information management and input/output modules. As a central processing unit of EWSDH, IIE is a decision support system for monitoring the operation characteristics and diagnosing unexpected behaviour of dam health. With the time-frequency domain localization properties and self-learning ability of wavelet networks based on wavelet frames, IIE builds some new monitoring models of dam health. The models are used to approximate and forecast the operation characteristics of dam. The methods of attributions reduction in rough sets theory are presented to diagnose adaptively the unexpected behaviour. The proposed system has been used to monitor dam health successfully. © 2011 Springer Science+Business Media B.V.
Chen Y.D.,Chinese University of Hong Kong |
Zhang Q.,Sun Yat Sen University |
Zhang Q.,State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering |
Lu X.,National University of Singapore |
And 2 more authors.
Quaternary International | Year: 2011
Monthly precipitation data covering 1956-2002 at 36 rain stations are analyzed to explore the spatio-temporal variability of the seasonal precipitation in the Dongjiang River basin, south China, using a continuous wavelet transform method, Mann-Kendall trend test, and simple regressive technique. The results indicated that: (1) increasing precipitation is observed in spring and winter; while decreasing precipitation is identified in summer and autumn. The increasing/decreasing precipitation trend mostly occurred near the lower/upper parts of the Dongjiang River basin; (2) the spatial distribution of the precipitation anomaly between 1956-1989 and 1990-2002 is similar to that of precipitation trend; (3) in general, 4 time periods are identified: 1956-1961 and 1975-1985 are featured by increasing areal average annual precipitation; while 1962-1974 and 1986-2002 are characterized by decreasing areal average annual precipitation. The areal average annual maximum precipitation has a decreasing trend; (4) the precipitation changes in the Dongjiang River basin are mainly controlled by the south-east Asian monsoon activities. Intensity of the south-east Asian monsoon carrying excess moisture is the main driving factor for precipitation changes in this study. This result will be greatly helpful for further research on availability and management of the water resources in the Dongjiang River basin, the main focus of an on-going research project. © 2010.
Li Y.,State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering |
Li Y.,Desert Research Institute |
Li Y.,Hohai University |
Acharya K.,Desert Research Institute |
And 2 more authors.
Ecological Engineering | Year: 2011
To improve water quality and alleviate eutrophication in Lake Taihu, the third largest freshwater lake in China, a Yangtze River water transfer project was initiated in 2002 to bring water from the Yangtze River to Lake Taihu to dilute and divert pollutants out of the lake. We used a three-dimensional numerical model, Environmental Fluid Dynamics Code, to study the impacts of water transfer on the transport of dissolved substances in the lake by using the concept of water age. In particular, the influences of inflow tributaries and wind forcing on water age were investigated. Model results showed that the effect of water transfer on transport processes in the lake is strongly influenced by hydrodynamic conditions induced by wind and inflow/outflow tributaries. During the simulation year (2005), the water ages in Lake Taihu were highly variable both spatially and temporally, with a mean of approximately 130 days in summer and 230 days in the other seasons. Southeasterly winds-dominant in the summer-could improve the quality of water by reducing the water age in the eastern areas of the lake, which are used as a drinking water source, and in Meiliang Bay, the most polluted bay. In terms of dilution, the most efficient flow rate for transferred water was predicted to be approximately 100m3/s. The spatial distribution of water ages showed that water transfer may preferentially enhance exchanges in some areas of the lake unless nutrient concentrations in the transferred water are reduced to a reasonable level. This study provides useful information for a better understanding of the complex hydrodynamic and mass transport processes in the lake, which is important for developing and implementing effective ecological restoration strategies in the region. © 2010 Elsevier B.V.
Shen Z.,State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering |
Ren H.,Hohai University
Advanced Materials Research | Year: 2012
According to the practical situation, the 3-D finite element model of Sandaowan underground powerhouse caverns on Taolai River is set up for analyzing the behaviors under earthquake action. Based on static stress field of the surrounding rock mass, and with the selection of appropriate seismic waves for dynamic time-history analysis method, the dynamic responses of underground powerhouse caverns are analyzed. It is shown that the time-history waveform of dynamic displacement of given points has a very similar variation regularity with that of acceleration, and the wave phases of both are almost synchronous. The dynamic displacements and principal stresses of the given points on rock walls are with the vibration of low-frequency characteristics, the acceleration response is with the vibration of high-frequency characteristics.
Huang Y.,Hohai University |
Yu Z.,University of Nevada, Las Vegas |
Yu Z.,State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering |
Zhou Z.,Hohai University
Journal of Hydrologic Engineering | Year: 2013
Groundwater inflow during tunnel excavation is a common problem in practice. How to accurately predict its occurrence during the construction is still a challenging problem for tunnel designers. A numerical method, basedon the coupled model involved in artery fractures described by a discrete fractured network model and ramification fractures and rock matrix describedby the equivalent continuum medium model, is developed to calculate the groundwater inflow of underground tunnel. The model is calibrated with the observed groundwater levels in the study domain. The results in the model calibration show that calculated and measured groundwater inflows agree well. Sensitivity analysis indicates that groundwater inflow increases with the increase of precipitation rate, hydraulic conductivity of rock matrix and fracture aperture. The effect of fracture aperture on groundwater inflow is predominant, owing to the occurring of many artery fractures around the tunnel, which leads to much groundwater flowing to the tunnel through these fractures. © 2013 American Society of Civil Engineers.
HUANG y.,Hohai University |
ZHOU Z.-f.,Hohai University |
YU z.-b.,State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering
Journal of Hydrodynamics | Year: 2010
The discrete version of solute transport equation for porous matrix depicted with the continuum model and the discrete fractured-network model are derived for fractured rocks with the Finite Volume Method (FVM). The two models are coupled according to the continuity condition of hydraulic head and concentration and the conservation of flow flux and mass flux in the contact plane between porous matrix and fractures. Numerical results show that the simulated concentration of the coupling model based on the FVM agrees well with that from analytical solution, which demonstrates that the coupling model can effectively be applied to the simulation of solute transport in fractured rocks. © 2010 Publishing House for Journal of Hydrodynamics.
LU Y.,State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering |
ZUO L.,State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering |
JI R.,Nanjing Hydraulic Research Institute |
LIU H.,Nanjing Hydraulic Research Institute
International Journal of Sediment Research | Year: 2010
The construction of hydropower projects, such as Xiluodu and Xiangjiaba Reservoirs, in the upper Yangtze River will lead to variations of the incoming water and sediment conditions and in turn changes in the deposition and erosion processes in the fluctuating backwater reach of the Three Gorges Project (TGP). In this paper, based on the water and sediment characteristics, a 2D mathematical model in the boundary-fitting orthogonal curvilinear coordinate system has been employed to predict the space-time changes of sedimentation in the Chongqing reach, part of the fluctuating backwater reach of TGP, in a period of 100 years with repetition of the 1961-1970 hydrological series with and without the construction of upstream reservoirs. The results show that in the case of natural hydrological series (NHS) without upstream reservoirs, severe deposition occurs in bays with concave bank lines, recirculation flow areas and wide-shallow reaches. In the case with the adjustment of upstream reservoirs, only a little deposition exists in bays with concave bank lines, and the amounts of deposition in the Yangtze River and Jialing River reaches are about 10-20% of those in the case of NHS. Therefore, this is helpful to maintain the effective capacity of the TGP Reservoir and utilize the bank lines of the Chongqing reach. © 2010 International Research and Training Centre on Erosion and Sedimentation and the World Association for Sedimentation and Erosion Research.
Ying Q.,Nanjing Hydraulic Research Institute |
Ying Q.,State key laboratory of hydrology water resources and hydraulic engineering
Advanced Materials Research | Year: 2014
Base on the mechanism of surge tank and measuring weir, an internal flat-pool measuring weir has been developed which can be applied in flow rate measuring area such as the hydraulics labs, the hydraulic engineering model labs and the river regulation project model labs. This new device functions well even with site limitation and unstable current. This passage introduces the mechanism of measuring weir with a few examples. © (2013) Trans Tech Publications, Switzerland.
Liu Y.,State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering |
Liu Y.,CAS Nanjing Institute of Geography and Limnology
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2012
Water body can be extracted from a satellite image with normalized difference water index (NDWI). It is commonly known that the index varies if extracting water body using multi-temporal images. This study selected 33 cloud-free scenes of MODerate-resolution Imaging Spectroradiometer (MODIS) data over the Poyang Lake region located in a subtropical area of China. Both the data with and without radiometric correction were used to extract lake water surface. The NDWI thresholds varied from date to date for the cases using either corrected or uncorrected data. Comparison showed that there were large differences between the two kinds of thresholds. Approximate 90% of the difference could be explained by the temporal influences including sun-target-satellite geometry and atmospheric conditions. © 2012 IEEE.
Chen J.,State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering |
Zhao S.,State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering |
Wang H.,State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering
Energy Procedia | Year: 2011
This paper uses fuzzy clustering analysis which is based on fuzzy equivalent relation to analyze the flood disaster of 30 provinces in China in 2008. The four indexes including affected area, number of deaths, housing collapse and direct economic losses is selected to carry on fuzzy cluster and grade division. The fuzzy equivalent matrix is extracted through transitive closure method and the cluster graph which classifies various degrees of severity of disaster areas clearly is obtained. The results show that fuzzy clustering analysis method is suitable for the grade division of flood disaster. © 2011 Published by Elsevier Ltd.