Project consisted of constructing a concrete spillway, grouted riprap
spillway channel, a riprap-lined fish conveyance channel and mechanical
and electrical upgrades to an existing diversion dam located on the
Truckee River east of Sparks, Nevada. Anderson Dragline, Inc. worked as a
grading and riprap subcontractor to S.D. Carmack Dirtmoving.
To accomplish installation of a new spillway and fish conveyance
channel, cofferdams were installed in a segment of the Truckee River
adjacent to the work sites. Pumping behind the cofferdams was continuous
during construction to keep the work areas dry. Pumped water was
discharged into stilling tanks prior to draining back into the
river. Floating turbidity curtains were also installed to maintain water
clarity downstream of the work area. Daily water quality sampling was
conducted to confirm compliance for turbidity and settleable solids
downstream of the work site.
A new concrete gate structure and spillway were constructed at the
upstream ends of the fish conveyance channel and spillway channel,
respectively. The fish conveyance channel and spillway channel were
excavated with some spoils being disposed on site. Remaining spoils were
screened and used in placement of new embankment and a stockpile for
future use by the agency.
Approximately 5,000 tons of riprap was placed to line the slopes and
invert in the 1,100 foot long fish conveyance channel. Two-ton and
four-ton boulders were placed across the channel at regular intervals in
the shape of a chevron to slow the flow velocity to enhance fish
passage. "Tuning" of the boulders was accomplished by adjusting the
position of the center boulders as directed by a fisheries biologist to
optimize the pooling of the water flow behind the boulders.
Approximately 20,000 tons of riprap were placed and grouted with concrete to face the spillway channel slopes.
Existing slide gate stems were removed and replaced at the dam. New
electric actuators were furnished and installed on the slide gates, with
a standby generator as emergency power source. Lead-based paint was
removed from an existing radial gate and the gate was re-painted.