Dam
and Powerplant
In the generation
of power, water from the reservoir enters gate-controlled intakes into the
powerhouse, rotates the turbines, and discharges through draft tubes into the
river below the dam.
Generators, mounted on the same shafts with the turbines, produce the
electric current.
It is increased in voltage by transformers and carried from the power
plant by transmission lines leading from the switchyard.
The power plant is
operated so as to use as much of the water flow as possible for power
production: during
periods of high stream flow, the spillway gates are opened to pass the water in
excess of the capacity of the turbines and as necessary for retention and
regulation of floodwaters through surcharge operation.
The upper portion of the reservoir, corresponding to a five-foot depth
above the normal headwater level, is provided for surcharge storage.
This storage space is utilized by raising all of the spillway gates in
small equal increments, thus permitting passage of some water under them but
retaining or forcing into storage all inflow to the reservoir in excess of the
spillway discharge and power releases.
The
reservoir is essentially a run-or-river type without regulating storage other
than for incidental flood control through surcharge operation, and for pondage
for power generation and lockages; hence, low water flow of the river will be
increased only indirectly through the use and passage of discharges from
upstream plants.
Such releases, however, result in a more sufficient and higher quality of
water for domestic and industrial consumption and use are effective in pollution
abatement downstream.
Due to the fairly constant level maintained under normal operating
conditions, the reservoir is well suited for conservation and recreational
purposes.
