Laboratory Studies of Screens for Diverting Juvenile Salmon and Trout from Turbine Intakes

Adams

Transactions of the American Fisheries Society

et al. 2000

In spring 1996 and 1997, we studied the prototype surface bypass and collector (SBC) at Lower Granite Dam on the Snake River in Washington. Our objectives were to determine the most efficient SBC configuration and to describe smolt movements and swimming behavior in the forebay. To do this, we used hydroacoustic and radiotelemetry techniques. The SBC was retrofitted onto the upstream face of the north half of the powerhouse to test the surface bypass method of diverting smolts from turbines. The SBC had three entrances, with mean velocities ranging from 0.37 to 1.92 m/s, and it discharged 113 m 3 /s through its outlet at Spill Bay 1, which was adjacent to the powerhouse. Different SBC configurations were created by altering the size and shape of entrances. During spring 1996 and 1997, river discharge was well above normal (123 and 154% of average, respectively). Powerhouse operations caused a strong downward component of flow upstream of the SBC. Many smolts (primarily steelhead and secondarily chinook salmon) were observed actively swimming upward in the water column. There were four times as many smolts diverted from turbines per unit volume of water with SBC flow than with spill flow, which indicated that the SBC may be an especially important bypass consideration in moderate-or low-flow years. The highest SBC efficiency (the proportion of total fish passing through the north half of the powerhouse by all routes that passed through the SBC) for any configuration tested was about 40%. Although no single SBC configuration stood out as the most efficient, the horizontal surface and maximum area configurations, or some combination of the two, are worth further investigation because they were moderately efficient.

Section: Discussionsupporting

confidence: 66%

Evaluation of the Prototype Surface Bypass for Salmonid Smolts in Spring 1996 and 1997 at Lower Granite Dam on the Snake River, Washington

Adams

Transactions of the American Fisheries Society

et al. 2000

“…Numerous investigations have provided evidence that in the open river channel the primary route of migrating juvenile salmon is within the bulk flow (thalweg), which usually contains the highest water velocities (Dehart 1991;Moser et al 1991;Nelson et al 1994). Studies also show, however, that juvenile salmon alter their behavior as they encounter structures such as a hydropower dam, where they tend to actively search for surface routes and are reluctant to sound with the bulk flow to pass via turbine routes (Andrew and Green 1960;Marquette and Long 1971).…”

Section: Flow and Fish Distributionmentioning

confidence: 99%

The Distribution and Flux of Fish in the Forebay of The Dalles Dam in 2003

Faber¹,

Hanks²,

Zimmerman³

et al. 2005

In spring and summer 2003, the Pacific Northwest National Laboratory led a team that conducted mobile and fixed hydroacoustic surveys in the forebay of The Dalles Dam for the U.S. Army Corps of Engineers-Portland District. This research was part of the Corps' Anadromous Fish Evaluation Program. The surveys provided information on the distribution and movement of smolt-sized fish relative to ambient factors such as flow, bathymetry, or diel cycle in the forebay at The Dalles Dam. A proposal for the use of a guidance structure in the forebay at The Dalles Dam, a modified version of a similar structure located at Lower Granite Dam, has recently been suggested by the U.S. Army Corps of Engineers and regional resource managers as a potential approach to improve the passage survival of juvenile salmon at the dam. The structure would be designed to divert fish from the powerhouse to the spillway. This project provided baseline data for the development of a behavioral guidance structure and surface bypass alternatives for juvenile salmon at The Dalles Dam. We sampled the forebay of The Dalles Dam one day and night each week for six weeks in the spring and another six weeks in the summer. Two research vessels were used. Each pushed a raft outfitted with sampling gear consisting of two split-beam transducers, four single-beam transducers, one acoustic Doppler current profiler (ADCP), a pitch-roll-heading indicator, and a differential global positioning system (GPS). The split-beam transducers provided information on the location, size, and movement of fish. The ADCP sampled the flow environment in which each fish was detected. One 12° split-beam transducer was aimed downward. The other split-beam transducers and the four single-beam transducers were all forward-looking 6° beams that were aimed to provide intensive sampling in the upper 9 m of the water column. The rafts were secured 7.5 m forward of the bow of the research vessels (15 m from the vessel's outboard motor) to minimize fish avoidance behavior. Mobile sampling was conducted from a research vessel and raft moving in a zigzag pattern extending from 180 m above the spillway to 1.8 km upstream of the spillway along 26 transects during each sampling period. A second research vessel sampled at 15 fixed-point locations for ten minutes at each point. From the fixed sampling we determined the rate and the direction of fish movement past those points (flux). Using the combined mobile and fixed sampling methods we were able to determine the distribution of smolt-sized fish and their movement patterns in the forebay. Smolt-sized fish were defined as those with a return signal of greater than-56 dB re||1µPa and less than-34 dB for spring fish (90-320 mm) or less than-45 dB for summer fish (90-105 mm). The species of smolt-sized fish that were targeted for springtime samples were juvenile steelhead trout (Oncorhynchus mykiss), juvenile yearling Chinook salmon (O. tshawytscha), juvenile coho salmon (O. kisutch), and juvenile sockeye salmon (O. nerka). Summertime samples were ...

“…The fish pass into the trash sluiceway and thence into the tailrace (Bentley & Raymond, 1969; Liscom, 1971). The majority of fish entering the turbine intakes are found near the ceiling as they pass the gatewell entrance (Long, 1968) and some zg % enter the gatewells, apparently swimming upwards in response to pressure (Bentley & Raymond, 1969; Marquette & Long, 1971). Tests with expanded metal plates that modify the flow pattern at the ceiling suggest that this proportion could be significantly increased by extending the time that fish can remain in the intake and inducing them to swim upstream (VanDenvalker, 1970).…”

Section: (A) Downstream Migrantsmentioning

confidence: 99%

Rheotropism in Fishes

1974

Summary (1) The fluid properties of air and water enable animals to orientate to flow and this behaviour in water is termed rheotaxis. Fish, however, have a wide range of responses to currents, extending beyond simple orientation, and the term rheotropism is therefore used as a ‘portmanteau’ word to describe all such reactions. (2) Fish detect currents directly by flow over the body surface or indirectly by other stimuli. Indirect responses are more common and occur in response to visual, tactile and inertial stimuli resulting from displacement of the fish by the current. Reactions to displacement of visual images are called optomotor reactions. The lateral line is not involved except in the detection of small localized jets of water. It has not been demonstrated that any fish can detect the current by electrical stimuli, although it is theoretically possible for some to do so. (3) In the basic form of rhotaxis the fish heads upstream and maintains station by stemming the current. Current detection thresholds fall within the range 0.4 to 10 cm/s for tactile stimuli but may be as low as 0.03 cm/s for visual stimuli. (4) Visual responses have been studied by simulating displacement by the current in optomotor apparatus. Fish respond to a rotating black‐and‐white‐striped background by compensatory movements of the head and eyes ‐ optokinetic nystagmus ‐ or by the optomotor reaction, in which the fish swims with the background. (5) Fish show an orthokinesis in optomotor apparatus, their mean swimming speed increasing with the speed of rotation of the background. The precise form of the relationship varies between species and there is also considerable individual variation in performance. Fish accelerate and decelerate relative to the background, fixating on a particular stripe for short periods. (6) Factors limiting the appearance of the optomotor response are contrast, illuminance, acuity, critical flicker fusion frequency and spectral sensitivity. (7) Fish tolerate retinal image movements equivalent to those received when they are carried forwards by the current but not to those received when they are carried backwards. There are ganglion cells in the optic tectum which are sensitive to the direction of movement of targets across the visual field. In the goldfish there are significantly more units sensitive to movements in the temporo‐nasal than in the opposite direction. (8) There are close parallels between the behaviour of fish in schools and in an optomotor apparatus. The optomotor response is apparently innate, occurring in newly hatched fry. (9) Physical and chemical factors can modify rheotaxis. Temperature and olfactory stimuli affect both the sign of the taxis and the kinetic component of the behaviour. (10) Thyroid hormones which are involved in the control of migration have been shown to affect the kinetic component of rheotaxis. (11) Fish show a number of hydrodynamic adaptations to life in currents. Morphological modifications are greatest in fish from torrential streams, which show extreme dorsoventra...