Closure to “Reservoir Level Rise under Extreme Driftwood Blockage at Ogee Crest” by Loïc Bénet, Giovanni De Cesare, and Michael Pfister

2021 ◽  
Vol 147 (12) ◽  
pp. 07021013
Author(s):  
Loïc Bénet ◽  
Giovanni De Cesare ◽  
Michael Pfister
Keyword(s):  
Reservoir Level

scholarly journals The hydraulic management of the Barra Bonita reservoir (SP, Brazil) as a factor influencing the temporal succession of its fish community

2007 ◽  
Vol 67 (3) ◽  
pp. 433-445 ◽  
Author(s):  
ML. Petesse ◽  
M. Petrere Jr. ◽  
RJ. Spigolon
Keyword(s):  
Fish Species ◽  
Fish Community ◽  
Abundant Species ◽  
Anthropogenic Stress ◽  
Reservoir Level ◽  
Species List ◽  
Adaptation Capacity ◽  
Reproductive Structures ◽  
Temporal Succession ◽  
Reproductive Compensation

The temporal succession of fish communities allows evaluating the environmental conditions and the adaptation capacity of the fish species to anthropogenic stress in reservoirs. The fish community at Barra Bonita reservoir was sampled in two different periods of the year (dry and rainy) and in three different areas of the reservoir (fluvial, transition, and lentic). The species list was compared to another four lists, trying to detect the transformations of the fish community for the last 15 years. In order to evaluate the adaptation of the present fish community to the hydraulic management of reservoir, the trophic and reproductive structures were studied. Temporal succession analysis shows little change in fish richness of the communities. The number of fish species varies between 23 and 39 for a total of 68 registered species. From this, 27 can be considered constant, 14 accessory and 27 accidental; the main differences observed were for Anostomidae, Loricariidae and Characidae families. In relation to the hydraulic management, we found a fish community stabilized and adapted to environmental stress. This is characterized by the dominance of small-sized fish species of opportunistic diet and high reproductive compensation (r-strategists). The overlap of biological cycles of the most abundant species with the reservoir level fluctuations points to the period from September to March-April as critical for reproductive success and only the species with partial reproductive strategy or parental care are best succeeded. These results, interpreted in the context of the reservoir aging process, indicate that Barra Bonita reservoir is entering a transition phase, between the colonization and aging stages.

Quantitative investigations of the hydraulic connection between a large reservoir and a buried valley aquifer in southern Alberta

2005 ◽  
Vol 42 (5) ◽  
pp. 1461-1473 ◽  
Author(s):  
B D Smerdon ◽  
C A Mendoza ◽  
A M McCann
Keyword(s):  
Groundwater Flow ◽  
Flow Model ◽  
Hydraulic Head ◽  
Water Levels ◽  
Groundwater Flow Model ◽  
Reservoir Level ◽  
Hydraulic Connection ◽  
Southern Alberta ◽  
Approximate Location ◽  
Pumping Rates

Quantitative investigations, including two aquifer tests and development of a three-dimensional (3D) groundwater flow model, were required to determine the hydraulic connection between an irrigation reservoir and a buried valley aquifer in southern Alberta. Evidence of seepage was detected in the buried valley aquifer 10 km east of the Pine Coulee reservoir at the onset of filling in 1999, when the reservoir level exceeded an elevation of 1035 m above sea level (a.s.l.). Concern for an increase in the local water table and the creation of artesian conditions in the aquifer prompted this study to determine the approximate location of a seepage window that appeared to be connecting the reservoir and aquifer. Observations of hydraulic head in the aquifer during the pumping tests revealed a barrier boundary when the reservoir level was at an elevation of 1035 m a.s.l. and a recharge boundary condition when the elevation exceeded 1039 m a.s.l. These data were used to calibrate a 3D groundwater flow model, which was needed to determine the hydraulic properties and approximate location of the leakage zone. The quantitative investigation showed that seepage likely occurred through the sideslopes of the flooded coulee, rather than through the low-permeability coulee floor sediments or the embankment dam. Further simulations illustrated the expected seepage rates at various reservoir supply levels and the pumping rates required for relief wells installed in the buried valley aquifer to maintain historic aquifer hydraulic head. A brief postanalysis indicated that the forecasted pumping rates were only 15% lower than have been required to maintain preconstruction water levels in the buried valley aquifer.Key words: dams, seepage analysis, groundwater modelling, buried valley aquifer, pumping test.

scholarly journals Temporary turbine and reservoir level management to improve downstream migration of juvenile salmon through a hydropower complex

2021 ◽  
pp. 4
Author(s):  
Stéphane Tétard ◽  
Romain Roy ◽  
Nils Teichert ◽  
Jocelyn Rancon ◽  
Dominique Courret
Keyword(s):  
Residence Time ◽  
Downstream Migration ◽  
Substantial Proportion ◽  
Juvenile Salmon ◽  
Reservoir Level ◽  
Flexible Approach ◽  
Hydropower Plants ◽  
Good Potential ◽  
And Migration ◽  
Level Lowering

Developing management rules to improve downstream migration of salmon smolts in large hydropower plants is essential to limit mortality and migration delay. A 2-year telemetry study was conducted to assess the efficiency of temporary measures to enhance the safety and speed of juvenile salmon passage through the Poutès dam (Allier River, France). 124 smolts were tracked through the reservoir and downstream of the dam, during implementation of turbine modulation and/or shutdown during night and reservoir level lowering. Level lowering significantly reduced median residence time from 3.4 days to 4.4 hours. However, even with high spill during turbine modulation, the risk of smolt being drawn toward the turbines was increased at low reservoir level due to the site's configuration, greater proximity to the surface and weak repulsive effect of the rack. Moreover, results revealed that a substantial proportion of smolts can migrate during daytime and twilight during floods, even at the beginning of the migration period. Thus targeted turbine shutdown has a good potential to protect smolts, but implementation requires studies taking account of site specificities and a flexible approach.

Hydrodynamic Change and Failure Mechanism of Qianjiangping Landslide, the Three Gorges Reservoir

2012 ◽  
Vol 170-173 ◽  
pp. 1938-1943 ◽  
Author(s):  
Jin Bing Wei ◽  
Hong Chun Zheng ◽  
Yu Long Cui
Keyword(s):  
Pore Water ◽  
Three Gorges Reservoir ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Three Gorges ◽  
Reservoir Level ◽  
Excess Pore Water Pressure ◽  
The Three Gorges ◽  
Qianjiangping Landslide ◽  
Excess Pore

Reservoir landslide is a severe geological hazard which is caused by the hydrodynamic change due to rainfall and fluctuation of reservoir level. The hydrodynamic change and its influence on landslide stability of Qianjiangping landslide before and after impoundment of the Three Gorges Reservoir are studied combining with its hydrogeological structure. There are two relatively independent hydrogeological units on both sides of the slipband. Before impoundment, the outlet of groundwater under slipband is above the river level, the supply and discharge of groundwater is in equilibrium, and the excess pore water pressure at the bottom of slipband is smaller or not exists. After impounding, the outlet of groundwater is under reservoir level and the discharge of groundwater is hindered, so the excess pore water pressure at the bottom of slipband will rises and the safety factor of the landslide will decreases. Combing with other factors, the stability of the landslide will further decreases and lead to landslide failure finally.

scholarly journals Movement of the Donglingxin landslide, China, induced by reservoir inundation and rainfall

2015 ◽  
Vol 3 (4) ◽  
pp. 2537-2564
Author(s):  
J. Yu ◽  
R. B. Wang ◽  
W. Y. Xu ◽  
L. Yan ◽  
J. C. Zhang ◽  
...  
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Level Fluctuation ◽  
High Mountains ◽  
Reservoir Level ◽  
Rainfall Events ◽  
West China ◽  
Groundwater Movement ◽  
Hydropower Plants ◽  
Depth Study

Abstract. With numerous high mountains, deep valleys and turbulent rivers, many hydropower plants have been constructed in the south-west China. Reservoir bank slopes are very common in this area, these slopes are widespread and quite often involved in deformation that can result in serious damage and casualties. In case of the Donglingxin landslide, for an in-depth study of processes that can trigger these events, the deformation characteristics and the failure mechanisms of the slope were performed on a detail scale, based on an intensive monitoring of rainfall events, reservoir level fluctuation and groundwater movement. The deformation of the upper part of slope is mainly induced by rainfall events, reservoir level fluctuation affects the deformation of the lower part of slope. The increase of pore water pressure may result in the failure of slope. The filed investigation suggest that the slope is unstable. Drainages is the only stabilization measure which can be implemented, due to very complex geological and geomorphology condition.

scholarly journals Flood Control Versus Water Conservation in Reservoirs: A New Policy to Allocate Available Storage

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 994
Author(s):  
Ivan Gabriel-Martin ◽  
Alvaro Sordo-Ward ◽  
David Santillán ◽  
Luis Garrote
Keyword(s):  
Return Period ◽  
Water Conservation ◽  
Flood Control ◽  
Global Optimum ◽  
Joint Optimization ◽  
Reservoir Level ◽  
Extreme Flood ◽  
Control Versus ◽  
Hydrological Safety ◽  
Reservoir Yield

The aim of this study is to contribute to solving conflicts that arise in the operation of multipurpose reservoirs when determining maximum conservation levels (MCLs). The specification of MCLs in reservoirs that are operated for water supply and flood control may imply a reduction in the volume of water supplied with a pre-defined reliability in the system. The procedure presented in this study consists of the joint optimization of the reservoir yield with a specific reliability subject to constraints imposed by hydrological dam safety and downstream river safety. We analyzed two different scenarios by considering constant or variable initial reservoir level prior to extreme flood events. In order to achieve the global optimum configuration of MCLs for each season, we propose the joint optimization of three variables: minimize the maximum reservoir level (return period of 1000 years), minimize the maximum released outflow (return period of 500 years) and maximize the reservoir yield with 90% reliability. We applied the methodology to Riaño Dam, jointly operated for irrigation and flood control. Improvements in the maximum reservoir yield (with 90% reliability) increased up to 10.1% with respect to the currently supplied annual demand (545 hm3) for the same level of dam and downstream hydrological safety. The improvement could increase up to 26.8% when compared to deterministic procedures. Moreover, dam stakeholders can select from a set of Pareto-optimal configurations depending on if their main emphasis is to maintain/increase the hydrological safety, or rather to maintain/increase the reservoir yield.

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