Effects of hydraulic cues in barrier environments on fish navigation downstream of dams.

Understanding how hydraulic cues in the barrier environment affect fish navigation is critical to fish migration in dammed rivers. However, most of the current research on the effects of hydraulic cues on fish navigation focuses on the effects of a single hydraulic parameter on fish migration and usually ignores fish sensory perception and swimming ability. This study presents an effective approach that combines a computational fluid dynamics model of a river with a model of fish behaviour to elucidate the effects of hydraulic cues in the barrier environment on fish migration paths and strategies by simulating the fish's perception of flow direction and their regulation of multiple hydraulic parameters.

Differences in the Natural Swimming Behavior of Individual and Schooling in Spatially Heterogeneous Turbulent Flows.

Spatially heterogeneous turbulent flow refers to nonuniform flow with coexisting multiple flow velocities, which is widely distributed in fish natural or husbandry environments, and its hydraulic parameters affect fish swimming behavior. In this study, a complex hydrodynamic environment with three flow velocity regions (low, medium, and high) coexisting in an open-channel flume was designed to explore volitional swimming ability, the spatial-temporal distribution of fish swimming trajectories, and the range of preferred hydrodynamic parameters of individual and schooling (three fish). The results showed that the swimming speed of individual fish during upstream migration was significantly higher than that of fish schools ( < 0.

Evaluating the impact of power station regulation on the suitability of drifting spawning fish habitat based on the fuzzy evaluation method.

Ecological regulation is an important means of reservoir adaptive management, but its effective evaluation faces two major difficulties: the response mechanism of fish spawning behavior is not completely clear, and how to establish a feedback regulation relationship of hydrological processes to improve the river environment is unknown. Based on a long-term series of early fish resources, hydrology, water temperature, and meteorology data, this research clarifies the fish spawning habitat requirements in the power station regulation environment, determines a habitat suitability evaluation index system and evaluation criteria, reveals the temporal and spatial variation characteristics of fish habitat suitability under power station regulation based on the fuzzy logic method, provides feedback to the existing regulation scheme, and proposes suggestions for sustainable adaptive management of the reservoir. The temporal and spatial variation characteristics of the spawning river sections habitat suitability are the comprehensive differences among multiple objectives and factors.

Evaluation of Volitional Swimming Behavior of Using an Open-Channel Flume with Spatially Heterogeneous Turbulent Flow.

Effective fishway design requires knowledge of fish swimming behavior in streams and channels. Appropriate tests with near-natural flow conditions are required to assess the interaction between fish behavior and turbulent flows. In this study, the volitional swimming behavior of S.

Identifying three-dimensional swimming corridors for fish to match their swimming characteristics under different hydropower plant operations: Optimization of entrance location for fish-passing facilities.

Fish that require migration are often diverse in the dam-built river, and some of them are benthic. For fish to pass efficiently across the dams, it is necessary to identify the swimming corridors and possible cluster areas of the target fish. However, previous studies have only predicted the two-dimensional swimming corridors of a single species.

Hydraulic characteristics of stepped spillway dropshafts for urban deep tunnel drainage systems: the case study of Chengdu city.

Cities in southwestern China experience urban drainage and overflow pollution after extreme rainfall events, which are major problems. In this study, a type of stepped spillway dropshaft suitable for drainage by deep tunnels in Chengdu was proposed and the hydraulic characteristics were investigated experimentally. The results showed that the nappe flow and strong turbulent deflected jet flow in the stepped spillway allowed the dropshaft to greatly dissipate energy.

Comparative study on the bioaccumulation of lead, cadmium and nickel and their toxic effects on the growth and enzyme defence strategies of a heavy metal accumulator, Hydrilla verticillata (L.f.) Royle.

The current hydroponic experiment investigated differences in the uptake, physiological response and defence mechanisms of Hydrilla verticillata (L.f.) Royle in response to three representative toxic heavy metals.

Mechanism Underlying Flow Velocity and Its Corresponding Influence on the Growth of , a Dominant Bloom Species in Reservoirs.

The effects of hydrodynamics on algae growth have received considerable attention, and flow velocity is one of the most frequently discussed factors. For , which aggregates resources and is highly resistant to environmental changes, the mechanism underlying the impact of flow velocity on its growth is poorly understood. Experiments were conducted to examine the response of algae growth to different velocities, and several enzymes were tested to determine their physiological mechanisms.

An Approach Based on the Protected Object for Dam-Break Flood Risk Management Exemplified at the Zipingpu Reservoir.

Dam-break flooding is a potential hazard for reservoirs that poses a considerable threat to human lives and property in downstream areas. Assessing the dam-break flood risk of the Zipingpu Reservoir in Chengdu, Sichuan Province, China, is critically important because this reservoir is located on the Longmen Shan fault, which experiences high seismic activity. In this paper, we develop an approach based on the protected object for dam-break flood risk management.

The Ecological Water Demand of in Tibet Based on Habitat Area and Connectivity.

Water resource regulation is convenient for humans, but also changes river hydrology and affects aquatic ecosystems. This study combined a field investigation and two-dimensional hydrodynamic model (MIKE21) to simulate the hydrodynamic distribution from 1 March to 30 April of 2008-2013 and establish the HDI (habitat depth suitability index) and HVI (habitat velocity suitability index) based on static hydraulic conditions at typical points. Additionally, by using MIKE21 to simulate the hydraulic state in the study area under 20 flow conditions from 530-1060 m/s, and combining these states with the HCI (habitat cover type suitability index), HDI, and HVI, we simulated the WUA (weighted usable area) and habitat connectivity under different runoff regulation scenarios to study the water requirements of during the spawning period in the Yanni wetland.

Identifying operation scenarios to optimize attraction flow near fishway entrances for endemic fishes on the Tibetan Plateau of China to match their swimming characteristics: A case study.

Attracting fish at fishway entrances is vital for ensuring fish passage efficiency, which requires consideration of the swimming characteristics of fish. The objective of this case study was to propose optimized flow conditions downstream of a dam on the Tibetan Plateau to attract fish into fishways. Six local endemic species of Cyprinidae: Schizothoracinae were considered as protection targets.

Effects of water depth on GBD associated with total dissolved gas supersaturation in Chinese sucker (Myxocyprinus asiaticus) in upper Yangtze River.

Spillway water falling from hydroelectric power plant dams in the upper Yangtze River creates a high pressure in plunge pools below the dams allowing gasses to be dissolved at high rates. The resulting supersaturation persists many miles downstream the dam which may elicit mortality in river fishes associated with gas bubble disease (GBD). We have in a two-year study (2014-15) evaluated the effect of water depth on development of GBD in an endemic and endangered fish species, the Chinese sucker Myxocyprinus asiaticus, 24 km downstream of Xiangjaiba dam.

Defense Mechanisms of Two Pioneer Submerged Plants during Their Optimal Performance Period in the Bioaccumulation of Lead: A Comparative Study.

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Ecohydraulogical Characteristic Index System of during Spawning Periods in the Yarlung Tsangpo River.

To address the species decline in aboriginal fish in the Yarlung Tsangpo River Basin and the lack of research on the habitat characteristics of fish spawning grounds, this paper studied the changing trends in runoff in spawning grounds and the habitat conditions characteristics of during the spawning period. In conventional approaches, inaccurate statistical results are obtained when a full river section is taken as the region to be assessed, so a new method for determining the statistical boundaries of characteristic indexes was proposed. By combining hydrological analyses, mathematical statistics, and numerical simulations, the statistical boundary of the index was determined, and a suitable range for the habitat characteristic indexes for the spawning field was finally obtained.

Effects of Total Dissolved Gas Supersaturation on the Swimming Performance of Two Endemic Fish Species in the Upper Yangtze River.

Total dissolved gas (TDG) supersaturation has been identified as one of the possible negative environmental effects of the construction of dams in the upper Yangtze River. Juvenile Chinese sucker and Prenant's schizothoracin fish were selected to evaluate the impact of TDG supersaturation on the swimming performance of fish in the Upper Yangtze River. The critical swimming speeds (U) of Chinese sucker were 4.