scholarly journals Hydrological evidence and causes of seasonal low water levels in a large river-lake system: Poyang Lake, China

2016 ◽  
Vol 47 (S1) ◽  
pp. 24-39 ◽  
Author(s):  
Jing Yao ◽  
Qi Zhang ◽  
Yunliang Li ◽  
Mengfan Li

Seasonal variations in local catchments and connected rivers lead to complex hydrological behaviours in river-lake systems. Poyang Lake is a seasonally dynamic lake with frequent low levels in spring and autumn, which may be triggered by the local catchment and Yangtze River. Based on two typical years, a hydrodynamic model combined with long term hydrological observations was applied to quantify the spatiotemporal impacts of the local catchment and Yangtze River on spring and autumn low water levels in Poyang Lake. As a first attempt, this study explored the spatial differences of the two influences. Simulation results showed that the contributions of the catchment and the Yangtze River were approximately 70% and 30% in spring 1963, and 5% and 95% in autumn 2006, respectively. The area of catchment influence was mainly distributed in channels and southern floodplains, with relatively uniform water levels. The area impacted by the Yangtze River mainly spanned from the northern portion of the waterway to the central lake, with strong spatial variability. This study focused on two typical years; however, the results can be extended to explain common hydrological phenomena and improve future strategies of water resource management in this river-lake system.

2017 ◽  
Vol 76 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Huai Chen ◽  
Lijun Zhu ◽  
Jianzhong Wang ◽  
Hongxia Fan ◽  
Zhihuan Wang

This study focuses on detecting trends in annual runoff volume and sediment load in the Yangtze river-lake system. Times series of annual runoff volume and sediment load at 19 hydrological gauging stations for the period 1956–2013 were collected. Based on the Mann-Kendall test at the 1% significance level, annual sediment loads in the Yangtze River, the Dongting Lake and the Poyang Lake were detected with significantly descending trends. The power spectrum estimation indicated predominant oscillations with periods of 8 and 20 years are embedded in the runoff volume series, probably related to the El Niño Southern Oscillation (2–7 years) and Pacific Decadal Oscillation (20–30 years). Based on dominant components (capturing more than roughly 90% total energy) extracted by the proper orthogonal decomposition method, total change ratios of runoff volume and sediment load during the last 58 years were evaluated. For sediment load, the mean CRT value in the Yangtze River is about −65%, and those in the Dongting Lake and the Poyang Lake are −92.2% and −87.9% respectively. Particularly, the CRT value of the sediment load in the channel inflow of the Dongting Lake is even −99.7%. The Three Gorges Dam has intercepted a large amount of sediment load and decreased the sediment load downstream.


2014 ◽  
Vol 30 (4) ◽  
pp. 321-330 ◽  
Author(s):  
Xijun Lai ◽  
Qun Huang ◽  
Yinghao Zhang ◽  
Jiahu Jiang

2015 ◽  
Vol 46 (6) ◽  
pp. 912-928 ◽  
Author(s):  
Y. L. Li ◽  
Q. Zhang ◽  
A. D. Werner ◽  
J. Yao

Lake hydrological simulations using physically based models are cumbersome due to extensive data and computational requirements. Despite an abundance of previous modeling investigations, real-time simulation tools for large lake systems subjected to multiple stressors are lacking. The back-propagation neural network (BPNN) is applied as a first attempt to simulate the water-level variations of a large lake, exemplified by the Poyang Lake (China) case study. The BPNN investigation extends previous modeling efforts by considering the Yangtze River effect and evaluating the influence of the Yangtze River on the lake water levels. Results indicate that the effects of both the lake catchment and the Yangtze River are required to produce reasonable BPNN calibration statistics. Modeling results suggest that the Yangtze River plays a significant role in modifying the lake water-level changes. Comparison of BPNN models to a 2D hydrodynamic model (MIKE 21) shows that comparable accuracies can be obtained from both modeling approaches. This implies that the BPNN approach is well suited to long-term predictions of the water-level responses of Poyang Lake. The findings of this work demonstrate that BPNN can be used as a valuable and computationally efficient tool for future water resource planning and management of the Poyang Lake.


2022 ◽  
Vol 30 (6) ◽  
pp. 0-0

The Yangtze River Economic Belt (YREB) is one of the most economically active regions in China, where an imbalance between the demand for land and the non-renewable is increasingly prominent. We present the patterns of land use in the YREB, then construct an evaluation index based on the Pressure-State-Response model. The TOPSIS model is used to evaluate sustainable land development in the YREB, and the spatial deductive characteristics of sustainable development levels are analyzed using three aspects: global spatial correlation, local spatial correlation, and regional difference. The results about the YREB show that: (1) The comprehensive sustainable land development score is average, indicating moderate sustainability with a fluctuating upward trend and good prospects. (2) The sustainable development levels of land have strong positive spatial correlation and agglomeration; the agglomeration characteristics follow a pattern similar to that of the status of economic development. (3) Sustainable development levels of land in the provinces and cities show great spatial differences.


Microbiome ◽  
2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Jiawen Wang ◽  
Qingxiang Liu ◽  
Xianfu Zhao ◽  
Alistair G. L. Borthwick ◽  
Yuxin Liu ◽  
...  

Abstract Background Diatoms are of great significance to primary productivity in oceans, yet little is known about their biogeographic distribution in oligotrophic rivers. Results With the help of metabarcoding analysis of 279 samples from the Yangtze River, we provided the first integral biogeographic pattern of planktonic and benthic diatoms over a 6030 km continuum along the world’s third largest river. Our study revealed spatial dissimilarity of diatoms under varying landforms, including plateau, mountain, foothill, basin, foothill-mountain, and plain regions, from the river source to the estuary. Environmental drivers of diatom communities were interpreted in terms of photosynthetically active radiation, temperature, channel slope and nutrients, and human interference. Typical benthic diatoms, such as Pinnularia, Paralia, and Aulacoseira, experienced considerable reduction in relative abundance downstream of the Three Gorges Dam and the Xiluodu Dam, two of the world’s largest dams. Conclusions Our study revealed that benthic diatoms are of particular significance in characterizing motile guild in riverine environments, which provides insights into diatom biogeography and biogeochemical cycles in large river ecosystems.


2019 ◽  
Vol 36 ◽  
pp. 1-5
Author(s):  
Moacyr Serafim-Júnior ◽  
Gilmar Perbiche-Neves ◽  
Fabio Lansac-Toha

Zooplankton exhibit several trends of variation in space and time, and these trends can be more evident in natural environments without anthropic perturbations. Examples of anthropic factors are climate change, eutrophication and construction of reservoirs. This study evaluated the influence of three factors – seasonality, type of environment and the presence of aquatic macrophytes – on various ecological attributes of rotifers in a river-lake system located in the Paraná River floodplain. Monthly samplings were conducted during 1993 and 1994. The mean species richness per sample was 60 species. The seasonality and the type of environment influenced the ecological attributes of rotifer assemblages, while the presence or absence of aquatic macrophytes did not. Species richness was highest in the lake system and during the months when water levels were low. Multivariate analysis indicates a small group of species associated with the low water-level phase. In contrast, many species were associated with high water levels or increasing water levels. The seasonal variation of hydrological cycle and the type of environment are the most important factors for rotifer structure in natural conditions.


Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2542 ◽  
Author(s):  
Mufeng Chen ◽  
Zengchuan Dong ◽  
Wenhao Jia ◽  
Xiaokuan Ni ◽  
Hongyi Yao

The multi-objective optimal operation and the joint scheduling of giant-scale reservoir systems are of great significance for water resource management; the interactions and mechanisms between the objectives are the key points. Taking the reservoir system composed of 30 reservoirs in the upper reaches of the Yangtze River as the research object, this paper constructs a multi-objective optimal operation model integrating four objectives of power generation, ecology, water supply, and shipping under the constraints of flood control to analyze the inside interaction mechanisms among the objectives. The results are as follows. (1) Compared with single power generation optimization, multi-objective optimization improves the benefits of the system. The total power generation is reduced by only 4.09% at most, but the water supply, ecology, and shipping targets are increased by 98.52%, 35.09%, and 100% at most under different inflow conditions, respectively. (2) The competition between power generation and the other targets is the most obvious; the relationship between water supply and ecology depends on the magnitude of flow required by the control section for both targets, and the restriction effect of the shipping target is limited. (3) Joint operation has greatly increased the overall benefits. Compared with the separate operation of each basin, the benefits of power generation, water supply, ecology, and shipping increased by 5.50%, 45.99%, 98.49%, and 100.00% respectively in the equilibrium scheme. This study provides a widely used method to analyze the multi-objective relationship mechanism, and can be used to guide the actual scheduling rules.


Author(s):  
Shaoda Liu ◽  
Dunxian She ◽  
Chao Gao ◽  
Giuseppe Amatulli ◽  
Luqing Wang ◽  
...  

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