U.S. patent application number 11/999831 was filed with the patent office on 2008-09-04 for structure and method for facilitating safe downstream passage of migrating fish around hydroelectric projects.
Invention is credited to Paul Tappel.
Application Number | 20080213045 11/999831 |
Document ID | / |
Family ID | 39733148 |
Filed Date | 2008-09-04 |
United States Patent
Application |
20080213045 |
Kind Code |
A1 |
Tappel; Paul |
September 4, 2008 |
Structure and method for facilitating safe downstream passage of
migrating fish around hydroelectric projects
Abstract
Structure and method for safe downstream passage of juvenile
fish of any species around hydroelectric dam projects using a
combination of deeply submerged extended turbine intakes and
surface-oriented bypass flows near the dam structure. The turbine
intakes are extended upstream from the dam face.
Inventors: |
Tappel; Paul; (Brier,
WA) |
Correspondence
Address: |
DOWREY RICKARDS
19119 NORTHCREEK PARKWAY, SUITE 106
BOTHELL
WA
98011
US
|
Family ID: |
39733148 |
Appl. No.: |
11/999831 |
Filed: |
December 6, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60873895 |
Dec 8, 2006 |
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Current U.S.
Class: |
405/81 |
Current CPC
Class: |
E02B 8/085 20130101;
Y02A 40/60 20180101 |
Class at
Publication: |
405/81 |
International
Class: |
E02B 8/08 20060101
E02B008/08 |
Claims
1. In a dam installation for holding a reservoir of water and
including at least one turbine with an opening on the upstream face
of the dam, a downstream passage system for migrating fish
traveling in an instinctive fish passage area in said reservoir,
comprising; an intake conduit extending from said turbine opening
in an upstream direction a distance exceeding random reverse
upstream travel of migrating fish said conduit terminating in an
extended turbine intake remote from the face of the dam and closely
adjacent the reservoir bottom beneath the instinctive fish passage
area, and a dam bypass system in the area of the dam creating flow
in the reservoir in the area of the dam face to maintain passive
fish movement toward the dam face and into the downstream passage
system.
2. The downstream passage system of claim 1 wherein; said intake
conduit extends upstream an approximate distance of between 20 to
2000 feet.
3. The downstream passage system of claim 2 wherein said extended
intake is located an approximate distance of between 50 to 100 feet
below the upper surface of the reservoir.
4. The downstream passage system of claim 3 wherein the bypass flow
rate is within approximately 5%-15% of the maximum turbine flow
rate.
5. The downstream passage system of claim 4 wherein said bypass
system is located within the top 50 feet of the reservoir water
column.
6. In a dam installation for holding a reservoir of water in a
flowing stream or river course and including a turbine structure
with a turbine opening in the upstream face of the dam for
channeling water through the turbine, said reservoir providing a
hydraulic head for driving said turbine, a safe instinctive
downstream passage system providing avoidance of said turbine
structure by migrating fish traveling in an instinctive fish
passage area located in the upper levels of said stream or river,
comprising; an intake conduit extending from said turbine opening
in an upstream direction away from the dam face, said intake
conduit having a bottom wall portion located closely adjacent the
bottom of said reservoir and a top wall portion downwardly inclined
from the upper portion of said turbine opening toward the bottom
wall portion and configured to form an extended turbine intake
remote from the face of the dam and below said instinctive fish
passage area, said extended intake being located a distance from
the upstream dam face that exceeds the observed random reverse
upstream travel of migrating fish of a targeted species and deep
enough to avoid intake of migrating fish instinctively sensing and
seeking to avoid the capture water velocity, turbulence and
vibrations associated with the intake, said extended intake being
of maximum width according to hydraulic modeling and dimensioned to
provide sufficient flow characteristics according to turbine intake
requirements, a dam bypass system in the upper level of said
reservoir in the area of the dam face for guiding fish around the
dam and into the project tailrace, said bypass system creating a
smooth flow in the reservoir in the area of the dam face to
maintain fish movement toward the dam face and into the bypass
system for all fish avoiding the deep extended turbine intake, said
bypass system presenting the only route for continued instinctive
downstream migration travel.
7. The downstream passage system of claim 6 wherein; said intake
conduit extends upstream an approximate distance of between 20 to
2000 feet.
8. The downstream passage system of claim 7 wherein said extended
intake is located an approximate distance of between 50 to 100 feet
below the upper surface of the reservoir.
9. The downstream passage system of claim 8 wherein the bypass flow
rate is within approximately 5%-15% of the maximum turbine flow
rate.
10. The downstream passage system of claim 9 wherein said bypass
system is located within the top 50 feet of the reservoir water
column.
11. The downstream passage system of claim 10 wherein the targeted
fish are migrating juveniles.
12. The downstream passage system of claim 11 wherein the targeted
fish species are salnonids.
13. The downstream passage system of claim 10, including; a
plurality of said turbines, intake conduits and extended turbine
intakes.
14. The downstream passage system of claim 13 wherein each said
extended turbine intakes include a trashrack across the opening
thereof, said system including; a pier system for supporting said
extended turbine intakes, and a gantry crane system for serving
said extended intakes and trash racks.
15. A method for safe downstream passage of migrating fish around a
dam project including at least one turbine comprising the steps of;
extending the turbine intake upstream from the dam a distance
exceeding observed random reverse upstream travel of migrating
fish, placing said turbine intakes below migrating fish travel in
the upper level of the dam reservoir to create deep intake
turbulence and vibration whereby migrating fish instinctively avoid
captive water velocity flow, creating a bypass flow to maintain
passive fish movement toward the dam face and into a safe
downstream passage system.
16. A method for providing safe downstream passage of migrating
fish around a dam installation for holding a reservoir of water;
said installation including at least one turbine having a turbine
intake on the upstream face of the dam and a downstream passage
system for migrating fish traveling in an instinctive fish passage
area in said reservoir comprising the steps of; extending said
turbine intake in an upstream direction a distance exceeding random
reverse upstream travel of migrating fish, locating said turbine
intake adjacent the reservoir bottom beneath the instinctive fish
passage area, and creating a bypass flow in the area of the dam to
maintain passive fish movement toward the dam face and into the
downstream passage system.
17. The method of claim 16 wherein said extended turbine intake is
extended upstream a distance of between 20 to 2000 feet.
18. The method of claim 17 wherein said extended turbine intake is
located an approximate distance of between 50 to 100 feet below the
surface of the reservoir.
19. The method of claim 18 wherein the bypass flow has a flow rate
within approximately 5%-15% of the turbine flow rate.
20. The method of claim 19 wherein said bypass flow is created
within the top 50 feet of the reservoir water column.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit under 35 U.S.C. 119(e)
of U.S. Provisional Patent Application Ser. No. 60/873,895 filed
Dec. 8, 2006.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The present disclosure relates to structure and method for
facilitating safe downstream passage of migrating fish around
run-of-the-river hydroelectric projects which include turbine
structures, by utilizing natural fish instincts to avoid entrance
into the turbines and which promote natural fish movement into safe
bypass flows around the dam project.
[0004] 2. Description of the Prior Art
[0005] Hydroelectric projects normally involve a large dam
structure with multiple electrical generator turbines which include
turbine intakes on the upstream face of the dam to channel water
flow through the turbine using the "head" or water pressure from
the reservoir on the upstream side of the dam. Many of these
hydroelectric dam projects are located on major river systems such
as the Snake and the Columbia River systems in the Northwest United
States. These streams or rivers are the natural habitat and
migration routes for fish, such as but not limited to salmon. The
mature fish return to travel upstream to spawn in the river and
tributaries of the river system and juvenile fish from hatcheries
or natural spawning grounds then instinctively travel downstream to
return to ocean habitats. As can well be appreciated, the problem
of providing for safe passage, of not only the upstream swimming
salmon but downstream migrating juvenile fish, is tremendous.
Although many different and even bizarre approaches have been
taken, the common approach is that of "juvenile fish attraction" as
concerns the downstream migration. To date, none of the efforts to
provide safe passage of the juvenile fish around these
hydroelectric projects have been satisfactory. Each season a highly
significant number of juvenile fish are entrained into the turbine
intakes where there are "capture water velocities" and these fish
are injured or killed by the turbines or associated hydraulic
forces. There is thus a tremendous need for a new approach in terms
of method and structures which will allow the juvenile fish to
bypass the turbine systems and to enter safe bypass flows from the
upper levels of the reservoir, around the dam, through a safe
bypass route(s) to be discharged into the project tailrace. The
present disclosure provides turbine intake structures for utilizing
the natural instincts of the downstream migrating juvenile fish
such as salmonids (or other fish species) to provide a safe passage
of the fish into a surface bypass flow around the dam. The present
concept, instead of utilizing the conventional "juvenile fish
attraction" approach, presents a fish guidance philosophy
180.degree. from conventional thinking, presenting fish with "the
lesser of evils".
SUMMARY
[0006] Structure and method for downstream passage of juvenile
salmonids and other fish species utilizes a combination of deeply
submerged extended intakes to hydroelectric projects, i.e. intakes
extended upstream from the dam face, and surface oriented bypass
flows near the dam structure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The drawing FIGURE illustrates the typical profile for a
turbine intake on a dam installation.
DETAILED DESCRIPTION
[0008] It will be understood that the hydroelectric project
schematically shown in the drawing is by way of example and not
limitation as a typical system and is not meant to represent any
particular project. It will also be understood that the bypass
system (not shown) may be any one of many known designs and
normally provides a smooth surface flow path near the upstream dam
face which is considered to be "conventional" and usually designed
to convey 5% to 15% (more or less) of the maximum turbine flow
downstream along with the safe passage of the juvenile fish. The
bypass normally provides smooth acceleration of transport
velocities in a downstream direction and the fish are captured by
the accelerating velocities toward the safe bypass route(s). These
fish end up safely discharged into the project tailrace. The
details of the bypass system, while necessary for safe passage, are
not a part of the present guidance system for the migrating
juvenile fish.
[0009] Referring to the drawing, a schematic cross section of the
dam structure is illustrated at 1. The typical turbine intake 2
will normally be provided with a slotted trashrack or the like
which is usually cleaned and maintained by a gantry crane (not
shown). The reservoir or pool area 4 backed up by the dam provides
the hydraulic head for the turbines, the normal pool level being
indicated at 6 and an existing reservoir bottom at 7. According to
the present system, an extended intake in the nature of a closed
conduit 8 extends the turbine intake upstream and will include a
lower or floor wall 9 extending along or closely adjacent the
reservoir bottom and an inclined upper or ceiling wall 10. The
ceiling wall 10 extends from the top of the conventional turbine
intake downwardly toward the floor wall 9, forming an intake
opening which is submerged as deeply as possible at the bottom of
the reservoir. The direction of flow is, of course, as indicated by
the arrows in the body of the reservoir 4. In the new intake
structure, the conventional trashrack, shown in dotted lines at 3,
would be moved to the new position shown at 11. It is of course
contemplated that a pier structure 12 of concrete or the like
would-be installed to support the relocated trashracks 11 and also
a gantry crane 13 provided to operate the trashrack in a
conventional manner.
[0010] The extended turbine intake 8 may range in length, in an
upstream direction, from 20 to 2000 feet from the dam face. The
choice of distance for the intake extension will be dependent upon
what is "significant" to the targeted juvenile fish species, i.e.
the distance the fish would not swim upstream randomly from the
face of the dam to the intake extension distance. This choice would
thus depend upon the behavior of the targeted fish species. The
extended turbine intake opening would be submerged with the tops of
the intake openings being as deep as practical considering
hydraulic modeling, structural and hydraulic calculations, entrance
and friction losses (head losses) and practical experience such as
maximum water velocity for intake trashracks. The deepest possible
setting for the tops of the turbine intakes or openings would, of
course, be the best. The extended intakes 8 would be constructed
using cast-in-place concrete, pre-cast concrete sections, metal, or
any other suitable materials. It is contemplated that the intake
openings 14 would be submerged in the range of 50-100 feet below
the surface 6 of the reservoir.
[0011] It will be understood, of course, that stop gates for the
turbine intakes would remain at the existing location or at any
other convenient stop gate location. The fish passage concept
includes the consideration that maximum practical width of the
turbine intake openings 14 would provide the deepest submergence
depth which would be the best for juvenile fish passage
reasons.
[0012] The present concept and guidance method presents the
juvenile fish with the "lesser of evils" for fish passage
downstream instead of relying on "juvenile fish attraction"
according to presently practiced methods. The fish migrating
downstream in groups or schools such as indicated at 16 in the
reservoir 4, regardless of their vertical position in the water
column, will detect a deep, dark flow movement into the turbine
intake opening 14 accompanied by a relatively rapid flow
acceleration, turbulence, noise and some vibration of the trashrack
structure. Multiple observations of downstream migrating salmonids
for example show that juvenile fish will be "repulsed" by these
conditions and will instinctively gradually swim away. The initial
detection of these adverse conditions by the fish will be at some
distance from the intakes, before "capture water velocities" are
present. All the fish instincts will be to swim away and this will
be easily possible at juvenile fish cruising speeds, the "burst
speed" not being necessary. The juvenile fish swimming away from
the deep, dark intake openings 14 will volitionally and
incrementally move into water volumes that are slowly moving toward
the dam face by maintenance of the aforementioned 5% to 15% (more
or less) surface-oriented fish passage systems at or near the dam
face. In short periods of time, fish avoiding the deep, dark
intakes would be surrounded by water heading toward the dam face.
Once within these water volumes the fish will be randomly "milling"
about, swimming short distances without a clear destination
discernible or intended. They will stay within water volumes
generally moving slowly toward the dam face and away from the deep
turbine intakes 14 upstream.
[0013] Bypass flows within 50 feet vertical of water surface, near
or at the dam face will maintain passive (i.e. fish milling
randomly) juvenile fish movement towards the dam face for all fish
avoiding the deep extended intake openings 14. This is so even
though the avoidance may be relatively short term. Surface bypass
flows of 5% to 15% of maximum turbine flows are initially
considered adequate, and this range of flows can only be refined by
multiple tests of juvenile fish passage with full-scale facilities.
Once at or near the face of the dam the fish will probably refuse
any outlet provided (based on past observations), and will mill
about randomly for hours, days or weeks. They will mill about
across the entire water width and depth accessible near the dam
face with no apparent pattern(s) to their movements. It is not
expected that they would randomly swim upstream as far as the
upstream turbine intake openings 14 because this movement would
defy their downstream migration instinct. They will mill about near
the dam face as currently observed at many hydroelectric projects.
Eventually, their instincts to migrate downstream is expected to
overcome their reluctance to enter whatever bypass system is
offered, and they enter the bypass system. By reason of instinct,
there would not be any other route for downstream passage except
the safe route offered near the dam face. The upstream turbine
openings 14 would no longer be perceived. Fish then entering the
bypass system(s) encounter a smooth acceleration of transport
velocities in a downstream direction, and are captured by the
accelerating velocities toward the safe bypass route(s). These fish
end up discharged safely into the project tailrace. It will be
understood, of course, that the bypass facilities may include
modified spill gates, normal spill gates, upward or downward acting
weir gates, Obermeyer gates, rubber dams, surface bypass spills,
orifice passages, ice and trash sluiceways (modified for fish
passage), sluice gates, and/or any surface-oriented (within top 50
feet of water column) downstream fish passage systems that have
been successfully implemented to date.
[0014] Although the present structure, system and method have been
described in considerable detail with reference to certain
embodiments or method steps, other embodiments and method steps are
possible within the purview of this disclosure. Therefore, the
spirit or scope of the present application should not be limited to
the description of the embodiments contained herein.
* * * * *