Analysis of movements and behavior of smolts swimming in hydropower reservoirs
Authored by Marcela Politano, Mark Timko, Antonio Arenas, Larry Weber
Date Published: 2015
DOI: 10.1016/j.ecolmodel.2015.05.015
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Abstract
Hydroelectric dams can be a barrier to migrating fish. An understanding
of smolt swimming behavior in reservoirs is of importance to effectively
design bypass systems and protect downstream migration. In this paper, probability distributions that describe smolt swimming behavior are
derived based on the combined analysis of measured fish locations and
Computational Fluid Dynamics (CFD) simulations. Acoustic tags were used
to record three-dimensional positions of Chinook salmon (Oncorhynchus
tshawytscha) in the forebay of Rocky Reach Dam and sockeye salmon
(Oncorhynchus nerka) and steelhead (Oncorhynchus mykiss) in the forebay
of Priest Rapids Dam. CFD simulations were used to determine flow
velocity and acceleration at the measured fish locations. Fish swimming
behavior in relation to flow field variables was assessed by solving
Newton's Second Law at each individual measured fish location.
Probability distributions of swimming orientation and thrust for
selected values of flow acceleration were obtained. Both fish drifting
with the flow and actively swimming were considered. According to this
study, as flow acceleration increases, smolts tend to orient themselves
against the flow and are less likely to drift. Out of the three species, steelhead show the strongest tendency to avoid flows with significant
vertical accelerations. The percent of fish drifting in low flow
acceleration zones (<2.0 x 10(-4) m/s(2)) was between 16 and 24\%.
However, for flow accelerations in the order of 2.0 x 10(-3) m/s(2), less than 8\% of fish were drifting. For fish actively swimming, increasing flow acceleration results in larger fish thrust. (C) 2015
Elsevier B.V. All rights reserved.
Tags
Performance
Chinook salmon
Salmon salmo-salar
Rainbow-trout
Lateral-line
Columbia river
Juvenile salmonids
Accelerating
flow
Fish movement
Dam