Hydraulic and earth engineering – Fluid control – treatment – or containment – Flow control
Reexamination Certificate
1999-12-18
2002-02-19
Bagnell, David (Department: 3673)
Hydraulic and earth engineering
Fluid control, treatment, or containment
Flow control
C405S082000, C405S083000, C119S219000
Reexamination Certificate
active
06347908
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to bypass guidance systems for conducting anadromous fish (e.g. salmon, American shad, blueback herring) as well as catadromous fish (e.g. eels) through dams and other man-made obstructions with maximum throughput and minimum stress to the migrating fish, as well as other migratory “silver underbodied” fishes, such as smelt, including Delta Smelt found in California's watercourses.
2. Description of the Prior Art
Through the world, land use associated with the development of dams and man-made lakes has adversely effected migrations of anadromous and catadromous fish. Where possible, for example at dams and their associated man-made lakes, bypass facilities have been built on the surface, overhead and submerged to facilitate migration particularly for anadromous fish, both for juveniles in the downstream direction and for adults in the upstream direction.
However, since there usually exist many such dams and lakes separating the ocean from spawning and rearing habitat, the time table of natural migration can be unduly prolonged by the presence of these obstacles. The bypass facilities constructed both at low-head and high-head dams to mitigate their adverse effect on migrating fish include but are not limited to the following: trapping and hauling, bypass or fishways, ladders or locks and fish elevators. More often than not, these bypass facilities inadvertently frighten fish, preventing the fish, particularly juveniles, from approaching the bypass facility in large numbers, and thus lead to little or no benefit despite the large costs involved. As a result, not only are many of the existing bypass facilities ineffective, but in addition most are also time consuming thereby unduly prolonging fish migration. Moreover, migrating juveniles and adults often fall easy prey to overhead and/or submerged predators at the termini of bypass facilities due to the means or methods employed. That is to say, no single fish bypass facility has yet been demonstrated to be biologically effective, practical to install and operate, and acceptable to environmental groups, or State or Federal agencies under the variety of site conditions outlined above.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide an effective method and system for guiding anadromous fish (e.g., salmon, steelhead, American shad, blueback herring) as well as catadromous fish (e.g. eels and as well Delta Smelt and similar fish) past dams, cooling and irrigation intakes, and other man-made obstructions.
Another object of the present invention is to guide such fish using their previously unrecognized natural responses to environmental stimuli.
One aspect of the invention enhances passage through dams and other man-made obstructions by artificially recreating at the water surface conditions associated with safe and/or hazardous aspects of the aquatic environment to entice migrating fish along a pre-selected and desired path.
Another aspect of the present invention is that it is capable of operating synergistically with presently existing systems for aiding fish migration, including but not limited to angled barracks positioned at entry basins, fixed screens of various shapes and orientations, velocity limiters, sluiceways, spillways, traveling screens, barrier nets and other facilities presently known to those skilled in the art, which are employed to reduce entrainment of the migrating fish in hydraulic turbines. The present invention can be advantageously combined with such conventional bypass facilities. For example, an existing fish ladder or bypass which may be combined with the present invention to safely transport the fish downstream. Trash sluiceways may also serve to transport screened fish downstream if associated with a bypass guidance system in accordance with the present invention.
Artificial environments that mimic naturally occurring conditions are surprisingly useful in eliciting a response that guides fish along a selected three-dimensional (3D) path around an obstacle in a relatively swift and low cost practical manner. It has been established that the selection criteria used by fish in choosing a path is based, inter alia, on a learned response that occurs usually during schooling in the fishes' natural (not artificial) habitat.
ANADROMOUS FISH
The present invention guides anadromous fish with a series of disturbed (or rippled) air-water interface regions contiguously arranged in a selected first direction across the air-water interface at a bypass entry basin adjacent to an obstruction such as a dam or lake. The ripples are preferably directed along the desired guidance path. The last disturbed interface region preferably has a narrowed exit that leads to the bypass facility. At each of these disturbed interface regions, artificial or natural light, diffusely refracted as it passes through the disturbed surface of the water, elicits a learned response from fish by establishing an aura-dominated passage which “silver underbodied” fish generally perceive as being safe because diffuse refracting light obscures their presence from any predator that may be present below or above the disturbed interface region. At the outlet of the bypass facility, another series of disturbed (or rippled) air-water interface regions is again established along a second direction at the exit basin together with artificial or natural light refracting from the disturbed surface of the water to again elicit the learned response described above. However, the size of the entry to the bypass guidance system at the outlet from the bypass facility reverses from that previously described at the entry thereto. That is, the entry to the bypass guidance system at the outlet from the bypass facility is narrow while the exit is large.
In one embodiment, the present invention includes a series of shower assemblies arranged in the selected first direction for the purpose of spraying fluid in a pre-selected pattern to creates the above-mentioned series of disturbed air-water interface regions. This creates a 3D path which “silver underbodied” fish usually perceive as being safe because they are hidden from view by diffuse refraction of light at the disturbed air-water interface regions. Thus nearly all “silver underbodied” fishes can be guided by systems in accordance with the present invention. The shower assemblies can be provided in various different arrangements and in associations with various artificial and natural elements as described in greater detail below.
LINEAR
For example, if the entry and exit basins at an obstruction such as a dam or lake is narrow, an overhead cable can be stretched across the basin in a selected direction starting at a bank adjacent to the bypass facility and ending at an opposite bank. This cable carries a series of lamp and shower assemblies cantilevered from the cable at selected locations. In operation, the lamp and shower assemblies create the above-mentioned series of disturbed air-water interface regions across the entry basin leading to the bypass facility. The area of the spray and illuminated regions can vary, preferably with them being largest at the entryway and smaller at the exit end or vice versa depending upon whether the bypass guidance system is located at the bypass facility's entry or exit basin, respectively. The combined disturbed interface regions can be arranged to establish a tapering or triangularly-shaped outline for the contiguous disturbed regions when they are viewed from above. In the entry basin, the triangularly-shaped outline has an apex near the entrance to the bypass facility. In the exit basin, the triangularly-shaped outline of the bypass guidance system reverses with its entrance being at the apex of a triangularly-shaped outline near the outlet from the bypass facility. Preferably the fluid applied to disturb the air-water interface regions is water, but could be compressed air.
In another embodiment, a series of buoys are anchored to the bottom of
Bagnell David
Lagman Frederick L.
Schreiber Esq. D. E.
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