Below are a list of key terms and definitions related to the HydroPASSAGE project.

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The rate of change of velocity per unit time. The Sensor Fish records three-dimensional acceleration as it passes through the hydropower turbine environment to indicate where live fish may be colliding with physical structures. Measured in meters/second squared (m/s2).

The design of hydropower turbines to reduce impacts of hydropower on the environment, while also using advanced engineering and technology to make hydropower more efficient.

The physical damage to body tissues caused by a rapid change in pressure. Commonly observed barotrauma injuries for fish include swim bladder rupture, hemorrhaging, and gas embolism and emphysema.

A relative measure of the impacts that hydropower structures will have on fish injury and mortality. Improved biological performance indicates that fish experience fewer adverse effects during passage.

The relationship between a stressor that a fish may experience during turbine passage with the predicted response (injury or mortality). Biological response relationships inform biological design criteria for turbine design and operation.

The Biological Performance Assessment (BioPA) toolset uses CFD simulations of the turbine design and operations to quantify the exposure of passing fish to rapid decompression, blade strike, shear forces and turbulence. Simulations are combined with fish dose-response relationships to objectively compare turbine designs and operations. BioPA is a Microsoft Excel-based program that integrates the exposure probabilities of stream traces and combines them with laboratory measurements of fish impacts. 

The ability to go from a non-operational (shutdown) configuration to an operational configuration without the use of external electrical power. 

The physical contact between a fish and turbine blade during hydropower turbine passage. This can result in injury and/or mortality for fish passing through the turbine environment. Fish can collide with many different structures in the turbine environment during passage, however, HydroPASSAGE Dose-Response testing has primarily focused on the impacts of blade strike. 

Computational fluid dynamics (CFD) models numerically simulate the flow of water through turbines in accordance with equations of fluid motion that are based on physical properties such as velocity, pressure, temperature, density and viscosity.

The physical contact between a fish and physical structures (e.g. wicket gates, turbine blades) during hydropower turbine passage. This can result in injury and/or mortality for fish passing through the turbine environment. BioPA and HBET measure the occurrence and magnitude of collisions for fish in the environment. 

The movement of fish into a hydropower facility due to the flow of water.

Operational and engineering modifications to dams that improve the survival rate of fish as they travel through hydropower structures. This includes juvenile bypass systems, fish screens, and changes in flows to reduce exposure to elevated total dissolved gas.

A structure, on or around a dam or other artificial barrier, that facilitates upstream passage of fish. 

A fish can encounter shear stresses when it passes through the interface of two water masses that are moving at different velocities or directions. This can result in injury and/or mortality for fish passing through the turbine environment.

A specific type of of hydropower turbine. Designed based on water-wheels, modern Francis turbines can be operated in a variety of head and flow environments. In general, Francis turbines have more blades than Kaplan turbines, and water enters the turbnie perpendicular to the rotational axis of the turbine. 

Hydropower Biological Evaluation Toolset (HBET) is an integrated suite of software tools designed to characterize hydraulic conditions of hydropower structures that can affect fish passage. HBET provides quantitative estimates of fish injury and mortality rates due to various physical stressors including strike, pressure, and shear.

  • HydroPASSAGE: the HydroPASSAGE project represents the Department of Energy’s Water Power Technology Office’s long-term efforts to develop tools that optimize hydropower turbines for improved downstream fish passage.

The harnessing of flowing water—using a dam or other type of diversion structure—to create energy that can be captured via a turbine to generate electricity.

A specific type of hydropower turbine used to generate power. The Kaplan Turbine is a propeller-type turbine that can operate efficiently over a large range of flows and head levels. In general, Kaplan turbines have fewer blades than Francis turbines and water flows both in and out of the turbine along the rotational axis. 

The capability of a power generating system to respond quickly to changes in electricity demand and generation. As compared to other types of renewable energy (e.g. solar, wind), hydropower has a superior operational flexibility.

A score that indicates the relative biological performance of a turbine design or operation. The PQI is calculated as a function of both the probability of exposure and the probability of adverse response to that level of exposure and is the main result output from BioPA. A PQI of 500 assumes that passage is expected to have no effect on the fish. The lower the PQI, the larger the adverse effect. 

The continuous physical force exerted against an object. CFD models and Sensor Fish provide estimates of pressure through the hydropower turbine environment to indicate where live fish may be subjected to rapid pressure changes. Measured in pascals (Pa).

The rapid (< 0.5 sec) decrease in pressures that are observed as water moves past the hydropower turbine blade. This can result in barotrauma for fish passing through the turbine environment.

The amount of rotation that a spinning object undergoes per unit time. The Sensor Fish records rotational velocity as it passes through the hydropower turbine environment to indicate where live fish may be encountering turbulence. Measured in radians/second (sec-1)

An autonomous sensor package used to gather information to characterize downstream passage conditions for fish. The Sensor Fish are deployed in turbines, spillways, and sluiceways and to measure changes in pressure, rotational velocity, temperature, orientation, and linear acceleration during passage.

A structure used to provide the release of flows from a dam into a downstream area. 

An external stimulus that can cause injury or mortality to fish (e.g. changes in pressure).

Enhancement of installed turbines to improve operational efficiency and biological response.

A low head dam.