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Feng L.,Wuhan University | Feng L.,University of South Florida | Hu C.,University of South Florida | Chen X.,Wuhan University | And 5 more authors.
Remote Sensing of Environment | Year: 2011

Using MODIS 250-m resolution data, we developed a novel approach to derive the bottom topography of Poyang Lake, the largest freshwater lake of China (> 3000 km2 at maximum inundation) for every year between 2000 and 2009. The approach differs from other traditional methods (sonar, Lidar, optical inversion, and Radar) but takes advantage of the fast-changing nature of the lake's inundation area. On every image, the water/land boundary is effectively a topographic isobath after correction for the water level gradient. Thus, the ~10/year carefully selected MODIS images provided incremental topographic isobaths, from which bottom topography was derived every year. Such-derived topographic maps were validated using limited historical data and other consistency checks. Most of the lake bottom showed an elevation of 12m to 17m (referenced against the elevation reference of the Woosung Horizontal Zero). Significant inter-annual variability of the bottom topography from 2000 to 2009 was found for some of the lake's bottom, with more areas associated with bottom elevation increases than decreases. The changes and inter-annual variability in the bottom topography were attributed to the combined effect of human activities (e.g., sand dredging and levee construction) and weather events. One example was the increased bottom elevation from 2002 to 2003, which was apparently due to the excessive precipitation in 2002 and the impoundment of the Three-Gorges Dam in 2003. The 10-year record of the bottom topography of this highly dynamic lake provides baseline information to monitor the impact of future engineering and management activities, to estimate the lake's water and sediment budgets, and to aid ship navigation. © 2011 Elsevier Inc.

Hu C.,Nanchang University | Hu C.,Jiangxi Provincial Institute of Water science | Froehlich K.,Viktor Wittner Gasse 36 7 | Zhou P.,Nanchang University | And 3 more authors.
Isotopes in Environmental and Health Studies | Year: 2013

Based on the monthly δ18O value measured over a hydrology period in precipitation, runoff of five tributaries and the main lake of the Poyang Lake Basin, combined with hydrological and meteorological data, the characteristics of δ18O in precipitation (δ18OPPT) and runoff (δ18OSUR) are discussed. The δ18OPPT and δ18OSUR values range from -2.75 to -14.12‰ (annual mean value = -7.13‰) and from -2.30 to -8.56 ‰, respectively. The seasonal variation of δ18OPPT is controlled by the air mass circulation in this region, which is dominated by the Asian summer monsoon and the Siberian High during winter. The correlation between the wet seasonal averages of δ18OSUR in runoff of the rivers and δ18OPPT of precipitation at the corresponding stations shows that in the Poyang Lake catchment area the river water consists of 23% direct runoff (precipitation) and 77% base flow (shallow groundwater). This high proportion of groundwater in the river runoff points to the prevalence of wetland conditions in the Poyang Lake catchment during rainy season. Considering the oxygen isotopic composition of the main body of Poyang Lake, no isotopic enrichment relative to river inflow was found during the rainy season with maximum expansion of the lake. Thus, evaporation causing isotopic enrichment is a minor component of the lake water balance in the rainy period. During dry season, a slight isotopic enrichment has been observed, which suggests a certain evaporative loss of lake water in that period. © 2013 Copyright Taylor and Francis Group, LLC.

Gao J.,Tianjin University | Chen Y.,Jiangxi Provincial Institute of Water science
Advanced Materials Research | Year: 2012

Closed concrete cut-off wall has been widely used in the reinforcement projects of earth-rock dam. However, the research on the cut-off wall was rare. In order to discuss the stress state of the wall under different engineering conditions, a coupled numerical model was established by considering coupled interaction, including contact between wall and dam, and coupling of stress and seepage. Taking the earth-rock dam which built on common foundation for example, the stress distribution of the wall and influencing law of different factors were mainly researched, including elastic modulus of the wall, deformation modulus of the dam filling materials, permeability coefficient of the dam foundation, etc. The conclusions had reference significance for the application and design and calculation method of concrete cut-off wall in the reinforcement projects of earth-rock dam. © (2012) Trans Tech Publications, Switzerland.

Xiao L.-Y.,Nanchang Institute of Technology | Lan Y.-Y.,Nanchang Institute of Technology | Zhong A.-M.,Jiangxi Provincial Institute of Water science
Advanced Materials Research | Year: 2014

In recent years, a large proportion of reservoir works in Jiangxi province have emerged different kinds of new diseases, which not only hold back the benefit but also affect the safety of these projects, to some extent. Based on investigating the present situation of dams in Jiangxi province and analyzing the reasons for deterioration condition in reservoir works, the main disease for hydraulic concrete structure of ill-dangerous dams is divided into several typical types and the characteristics of the existing problems are given as well as some control measures. © (2014) Trans Tech Publications, Switzerland.

Liu J.-T.,Jiangxi Provincial Institute of Water science | Yang Y.-S.,Jiangxi Provincial Institute of Water science | Jiang J.-H.,CAS Nanjing Institute of Geography and Limnology | Gao J.-F.,CAS Nanjing Institute of Geography and Limnology
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2011

Based on the risk analysis of cynaobacteria bloom hazard in Taihu Lake, the index system for the cynaobacteria bloom risk evaluation was constructed. Combined with the concept of risk evaluation, the risk evaluation method was established. On the basis, the hazard risk, exposure risk, vulnerability risk, and comprehensive risk of the nine lake regions in Taihu Lake were evaluated taking 2008 as the base year. The largest risk regions were in northern part of Taihu Lake, especially the Gonghu Lake was the most serious as the water source area. The risk in Zhushan Lake, Meiliang Bay and western coastal was middle for the large hazard risk. In the other regions, the risk in Xuhu Lake, southern coastal and big Taihu Lake was light risk, and there were almost no cyanobacteria bloom outbreak risk for the light eutrophication and large vegetation cover in the southwest regions of Taihu Lake.

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