scholarly journals Coupling mechanism of volume strain and water level in the Fuxin well located in a geothermal area before and after the 2011 Mw 9.1 Tohoku earthquake

2016 ◽  
pp. 61-71
Author(s):  
Yan Zhang
Keyword(s):  
Water Level ◽  
Tohoku Earthquake ◽  
Coupling Mechanism ◽  
Geothermal Area ◽  
Volume Strain ◽  
Before And After

Effects of the Belo Monte hydro-electric-dam complex on crocodilians in the Xingu River, Brazilian Amazonia

2021 ◽  
pp. 1-8
Author(s):  
Zilca Campos ◽  
Fábio Muniz ◽  
William E. Magnusson ◽  
Guilherme Mourão
Keyword(s):  
Water Level ◽  
Xingu River ◽  
Hydroelectric Dam ◽  
River Reservoir ◽  
Before And After ◽  
Collateral Effects ◽  
Generating Capacity ◽  
Reservoir Filling ◽  
Belo Monte

Abstract The Belo Monte hydroelectric dam on the Xingu River has the third largest generating capacity of any hydroelectric dam in the world. We conducted surveys of crocodilians (Caiman crocodilus, Paleosuchus trigonatus) by boat in the Xingu River at the site of the dam prior to (2013-2015), and after filling (2016-2017). While the number of C. crocodilus sighted decreased with increasing water level, there was no difference in numbers prior to, and after reservoir filling. The number of P. trigonatus was unaffected by both water level prior to and after reservoir filling. Reservoir filling had little effect on the number of crocodilians using the forest around the Xingu River reservoir. Most crocodilians seen in forest surveys were P. trigonatus, both before and after reservoir filling, but C. crocodilus was recorded occasionally in the forest. It seems that most Amazonian crocodilians are sufficiently generalist to adapt to the new conditions created by the construction of dams, at least in the short-term. However, there may be long-term collateral effects on crocodilian populations from dams, due to as deforestation and improved access for hunters.

scholarly journals Precipitation Changes in the Three Gorges Reservoir Area and the Relationship with Water Level Change

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6110
Author(s):  
Qin Li ◽  
Xiuguo Liu ◽  
Yulong Zhong ◽  
Mengmeng Wang ◽  
Manxing Shi
Keyword(s):  
Water Level ◽  
Three Gorges Reservoir ◽  
Precipitation Anomaly ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Reservoir Area ◽  
Precipitation Concentration ◽  
The Three Gorges ◽  
Before And After ◽  
Precipitation Changes

As the largest hydroelectric project worldwide, previous studies indicate that the Three Gorges Dam (TGD) affects the local climate because of the changes of hydrological cycle caused by the impounding and draining of the TGD. However, previous studies do not analyze the long-term precipitation changes before and after the impoundment, and the variation characteristics of local precipitation remain elusive. In this study, we use precipitation anomaly data derived from the CN05.1 precipitation dataset between 1988 and 2017 to trace the changes of precipitation before and after the construction of the TGD (i.e., 1988–2002 and 2003–2017), in the Three Gorges Reservoir Area (TGRA). Results showed that the annual and dry season precipitation anomaly in the TGRA presented an increasing trend, and the precipitation anomaly showed a slight decrease during the flood season. After the impoundment of TGD, the precipitation concentration degree in the TGRA decreased, indicating that the precipitation became increasingly uniform, and the precipitation concentration period insignificantly increased. A resonance phenomenon between the monthly average water level and precipitation anomaly occurred in the TGRA after 2011 and showed a positive correlation. Our findings revealed the change of local precipitation characteristics before and after the impoundment of TGD and showed strong evidence that this change had a close relationship with the water level.

scholarly journals Contrasting Hydrodynamic Responses to Atmospheric Systems with Different Scales: Impact of Cold Fronts vs. That of a Hurricane

2020 ◽  
Vol 8 (12) ◽  
pp. 979
Author(s):  
Wei Huang ◽  
Chunyan Li
Keyword(s):  
Water Level ◽  
Cold Front ◽  
Volume Transport ◽  
Water Volume ◽  
Cold Fronts ◽  
Barataria Bay ◽  
Before And After ◽  
Frequent Exchange ◽  
The Right ◽  
Mexico Coast

In this paper, subtidal responses of Barataria Bay to an atmospheric cold front in 2014 and Hurricane Barry of 2019 are studied. The cold fronts had shorter influencing periods (1 to 3 days), while Hurricane Barry had a much longer influencing period (about 1 week). Wind direction usually changes from southern quadrants to northern quadrants before and after a cold front’s passage. For a hurricane making its landfall at the norther Gulf of Mexico coast, wind variation is dependent on the location relative to the location of landfall. Consequently, water level usually reaches a trough after the maximum cold front wind usually; while after the maximum wind during a hurricane, water level mostly has a surge, especially on the right-hand side of the hurricane. Water level variation induced by Hurricane Barry is about 3 times of that induced by a cold front event. Water volume flux also shows differences under these two weather types: the volume transport during Hurricane Barry was 4 times of that during a cold front. On the other hand, cold front events are much more frequent (30–40 times a year), and they lead to more frequent exchange between Barataria Bay and the coastal ocean.

scholarly journals A numerical geotechnical model for computing soil slides at banks of water reservoirs

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Nils Reidar B. Olsen ◽  
Stefan Haun
Keyword(s):  
Numerical Model ◽  
Water Level ◽  
Stokes Equations ◽  
Limit Equilibrium ◽  
Three Dimensional ◽  
Field Measurements ◽  
Navier Stokes ◽  
Adaptive Grids ◽  
Groundwater Levels ◽  
Before And After

AbstractSoil slides can occur when the water level in a lake or a reservoir is lowered. This may take place in situations when a reservoir is flushed to remove sediments. The current study describes a three-dimensional numerical model used for the simulation of reservoir flushing that includes the slide movements. The geotechnical failure algorithms start with modelling the groundwater levels at the banks of the reservoir. A limit equilibrium approach is further used to find the location of the slides. The actual movement of the sediments is computed by assuming the soil to be a viscous liquid and by solving the Navier–Stokes equations. The resulting bed elevation changes from the slides are computed in adaptive grids that change as a function of water level, bed erosion and slide movements. The numerical model is tested on the Bodendorf reservoir in Austria, where field measurements are available of the bank elevations before and after a flushing operation. The results from the numerical simulations are compared with these observations. A parameter test shows that the results are very sensitive to the cohesion and less sensitive to the E and G modules of the soil.

Health Identification of Water Resources-Ecological-Socioeconomic System of Baiyangdian Wetland

2011 ◽  
Vol 183-185 ◽  
pp. 2340-2345
Author(s):  
Xin Yi Xu ◽  
Mei Liu ◽  
Feng Wang
Keyword(s):  
Water Resources ◽  
Water Level ◽  
North China ◽  
Social Economy ◽  
Freshwater Wetland ◽  
Coupling Mechanism ◽  
Coordinated Development ◽  
Ecological Balance ◽  
Socioeconomic System ◽  
Baiyangdian Wetland

As the largest freshwater lake in north China, Baiyangdian Wetland plays an important role in ecological balance of the north China plain. Besides the high ecological value, Baiyangdian Wetland retains a health development of social economy. According to this special shallow freshwater wetland, based on the concept of coordinated development of resources, environment and social economy, the relativity of water resources subsystem, ecological subsystem and socioeconomic subsystem has been explained in detail, and a hierarchy that has three layers has been built up, and what’s more, the health index (HI) has been calculated using analytic hierarchy process (AHP). The results showed that the water resources-ecological-socioeconomic system of Baiyangdian Wetland was at the status of sub-health even at the high frequency water level (7.9 m). When the water level is higher or lower than 7.9 m, the health condition will be worse. Every subsystem is a chain of the coupling system, whichever of the subsystems changes will affect other chains. Thus, it is necessary to implement management measures according to the coupling mechanism of different subsystems; it can provide theoretic and practical guidance to the coordinated development of ecological balance and social economy of Baiyangdian Wetland.

scholarly journals Hydrodynamic Influence Dabanhu River Bridge Holes Widening Based on Two-Dimensional Finite Element Numerical Model

2018 ◽  
Vol 38 ◽  
pp. 03042
Author(s):  
Dong Feng Li ◽  
Fu Qing Bai ◽  
Hui Nie
Keyword(s):  
Water Level ◽  
Network Flow ◽  
Water Surface ◽  
Two Dimensional ◽  
Surface Gradient ◽  
Before And After ◽  
Dimensional Finite Element ◽  
Vector Distribution ◽  
Hydrodynamic Factors ◽  
Range Of Influence

In order to analyze the influence of bridge holes widening on hydrodynamic such as water level, a two-dimensional mathematical model was used to calculate the hydrodynamic factors, river network flow velocity vector distribution is given, water level and difference of bridge widening before and after is calculated and charted, water surface gradient in seven different river sections near the upper reaches of bridges is counted and revealed. The results of hydrodynamic calculation indicate that The Maximum and the minimum deducing numerical value of the water level after bridge widening is 0.028m, and 0.018m respective. the seven sections water surface gradient becomes smaller until it becomes negative, the influence of bridge widening on the upstream is basically over, the range of influence is about 450m from the bridge to the upstream. reach

Spatial and seasonal distribution of phosphorus in the mainstem within the Three Gorges Reservoir before and after impoundment

2015 ◽  
Vol 73 (3) ◽  
pp. 636-642 ◽  
Author(s):  
Baofeng Lou ◽  
Shiyong Yin
Keyword(s):  
Water Level ◽  
Three Gorges Reservoir ◽  
Suspended Solids ◽  
Seasonal Distribution ◽  
Three Gorges ◽  
Target Level ◽  
Wet Season ◽  
The Three Gorges Reservoir ◽  
The Three Gorges ◽  
Before And After

The Three Gorges Reservoir (TGR) began to store water in 2003. The water level reached 135 m in 2003, 156 m in 2006, 172 m in 2008 and 175 m (target level) in every year from 2010 through 2013. Impacts of dams on the environment are a concern all over the world. A major concern for reservoirs is phosphorus and possible eutrophication. Therefore, total phosphorus (TP) in the TGR mainstem was determined at five stations (S1–S5) from 1998 through 2013 to investigate variations of phosphorus with water level elevations. Results revealed that a new spatial and seasonal TP distribution has occurred after the impoundment. TP levels in the reach between S3 (nearly 300 km from the dam) and S5 (near the dam) have decreased sharply compared with those before the impoundment. The reduction degree of TP in wet season was greater than in dry season. Additionally, TP spatially decreased from upstream to the dam after the impoundment. The reduction of TP levels was mainly attributed to the settling of suspended solids and adsorbed phosphorus. These findings will inform research about transport and fate of phosphorus in TGR and Yangtze River. The challenge remains to implement measures to limit the release of phosphorus from sediments.

The Riverbed Evolution and its Influence on Channel in Tunaozi Reach after Three Gorges Water Storage

2012 ◽  
Vol 226-228 ◽  
pp. 2323-2327
Author(s):  
Hua Fu ◽  
Xu He ◽  
Yao Chang Ma ◽  
Yun Yun Yang
Keyword(s):  
Water Level ◽  
Longitudinal Section ◽  
Three Gorges Project ◽  
Three Gorges ◽  
Channel Condition ◽  
Flood Season ◽  
The Three Gorges ◽  
Smooth Channel ◽  
Before And After ◽  
The Three Gorges Project

Tunaozi reach is one of the three famous sediment depositing reach on the Sichuan section of Yangtze River. It’s on the fluctuation backwater area when the Three Gorges Project is operated at the level of 135 m. According to the measured data before and after impoundment, this paper analyzes and calculates the sediment of the reach, and discusses the variation of silting and scouring of the reach after impoundment. Thus, this paper will have a study on the reason that silting and scouring lead to channel condition change. The result as follow: after impoundment, the bank-up water level of the reach has been head up 2 m during the flood season, sediment deposition becomes heavier than before impoundment; in post-flood season, the water level is 139m in November, it has been head up 7 m, compared with low water level in natural, current slowly flow further, the silt lack of enough scour in flood season, it leads to cumulative deposition. Until December 2005, thalweg plane position move left 200 m after impoundment. The maximum silting height of the thalweg longitudinal section is 30 m. The prime channel has been basically silted flat, year. Since the Three Gorges reservoir began to store water for three years, in low water level periods, ship tank is out of shallow, some timely dredging measure should be taken and make sure the smooth channel.

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