7316

• UCREFRP Catalog Number: 7316
• Author: U.S. Army Corps of Engineers.
• Title: Redlands Dam Fishway Feasibility Study, Gunnison River, Colorado.
• USFW Year: 1986.
• USFW - Doc Type: Walla Walla.
• Copyright Material: NO

• to a junction pool. From this pool, the ladder structure turns down-
stream, for nine pools, to gain elevation, and then turns upstream again
to raise the last 10 pools. Upstream of the last pool, the fishway exit
extends for more than 20 feet into the forebay. The slope of the ladder
floor is 1 foot vertical to 20 feet horizontal. The ladder also has pro-
visions to adjust the length and number of pools. The pool length is
adjusted by placing or removing lightweight weir boards (refer to
paragraph 3, Operational Flexibility).
b. The fishway exit area is large enough to accommodate an
8-foot-wide, 16-foot-long, 5-foot-high trap. The fish are guided into
the trap through a V-shaped notch in the trap structure. Fish easily
find their way into the trap but do not easily find their way out through
the notch. The trap allows for exiting or trapping of fish by means of
an upstream gate. The downstream end of the notch can be closed and the
fish can be crowded to the water surface for observation or tagging.
Fish can also be removed from the ladder, while being contained in the
trap, by means of a hoist on the work platform.
c. This alternate provides vertical bar screens upstream
from the headgates to prevent migrating fish from entering the power
canal, if necessary. A trash shear boom is also provided to reduce
debris problems at the fish ladder and screens.
d. The ladder also has provisions for auxiliary attraction
water supply at the fish entrances and at the junction pool. Water enters
from the forebay through a trashrack under the ladder exit and is piped
to the diffusers. A valve is provided at each diffuser to adjust the
quantity of attraction water. The maximum velocity into the trashrack
and from the diffusers is 0.5 fps. The drop in water surface at the
fishway entrance is regulated by side-opening slide gates across the
entrance opening adjacent to the diffuser.
e. Security fencing will be installed across the west side
of the sluice gate area. Also, grating will be installed to cover the
fish trap and provide access over the ladder. For additional security
measures, provisions for future grating installation will be made to
cover the entire ladder, if necessary.
2. Description of Standard Operation.
a. The vertical placement of the fish ladder entrances and
exit accommodates low flow conditions as well as higher flows. A minimum
3-foot water depth i s desired i n the entrance pool and al 1 1 adder pool s
• during normal operation. From preliminary tailwater computations, low
tailwater was calculated as elevation 4,563.0 feet. This elevation was
11