Canadian Dam Association Bulletin - Spring 2018 - 12

1. INTRODUCTION
The Peace River hydroelectric system in British Columbia consists of
two existing projects, G.M. Shrum
Generating Station at the W.A.C.
Bennett Dam and Peace Canyon
Generating Station at the Peace Canyon
Dam. The Site C Clean Energy Project
which is currently under construction
would be the third facility in the Peace
River hydroelectric system.
The Site C Clean Energy Project's
60 m high, 1 km long earthfill dam
is located 83 km downstream of the
Peace Canyon Dam and 7 km southwest of Fort St. John. The reservoir,
with a surface area of approximately
9,310 hectares, will extend back to the
tailrace of the Peace Canyon Dam. The
powerhouse and spillway located on
the south bank are constructed on top
of a roller compacted concrete buttress. The spillway and power intakes
will be fed by an approach channel
around the south end of the dam

(see Figure 1). The project will have six
generating units with a total capacity
of 1,100 MW, producing an average
of 5,100 GWh of electricity annually.
A description of the other hydraulic
features of the project can be found in
a related paper on general hydraulic
features (Croockewit et al. 2017).
Site C will take advantage of regulation of the Peace River that is provided
by the W.A.C. Bennett Dam, generating
electricity from water discharged by
the G.M. Shrum Generating Station
and the Peace Canyon Generating
Station. Most of the inflow into the
Site C reservoir will come from the
Peace Canyon Dam. Unregulated
inflows coming from the Halfway
River, Moberly River and other small
tributaries downstream of Peace
Canyon Generating Station comprise
approximately 6% of average annual
Site C inflow.
The capacity of the two 10.8 m diameter submerged diversion tunnels was

governed by design flood conditions
during construction. To fill the Site C
reservoir with average inflows from
upstream while maintaining minimum downstream environmental
flow releases, one tunnel will be
closed and the capacity of the other
diversion tunnel needs to be reduced.
The 1980's historic design of the
Site C diversion tunnels (unconstructed) proposed that the first stage
of reservoir filling be done by closing
one tunnel and using the regulating
gates at relatively small gate openings
in the other diversion tunnel inlet
structure to restrict capacity while
maintaining the minimum required
downstream flow. The energy of the
rising reservoir would be dissipated
by a hydraulic jump that would form
downstream of the regulating gates
within the tunnel. The hydraulic
jump would travel down the tunnel
as the reservoir elevations rose. The
relatively poor rock conditions and

Reservoir

Access Road
Diversion Tunnel Inlet

Earthfill Dam
Transmission Lines

Approach
Channel
Overflow
Auxiliary Spillway

Generating
Station

Diversion Tunnel Outlet

RCC Foundation for
Concrete Structures Above

Spillway

Access Road

Figure 1 - Site C Project General Layout (final layout may differ from what is shown)
12

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Table of Contents for the Digital Edition of Canadian Dam Association Bulletin - Spring 2018

Board of Directors
President’s Message
Site C Clean Energy Project Diversion Tunnel Orifices for Energy Dissipation During Reservoir Filling
Application for 2018 CDA Scholarships
CDA Presents 2017 Scholarships
ICOLD Corner
CDA Conference 2018
EIC Awards Gala
Buyers’ Guide and Trade List
Canadian Dam Association Bulletin - Spring 2018 - 1
Canadian Dam Association Bulletin - Spring 2018 - cover1
Canadian Dam Association Bulletin - Spring 2018 - cover2
Canadian Dam Association Bulletin - Spring 2018 - 3
Canadian Dam Association Bulletin - Spring 2018 - 4
Canadian Dam Association Bulletin - Spring 2018 - 5
Canadian Dam Association Bulletin - Spring 2018 - 6
Canadian Dam Association Bulletin - Spring 2018 - Board of Directors
Canadian Dam Association Bulletin - Spring 2018 - President’s Message
Canadian Dam Association Bulletin - Spring 2018 - 9
Canadian Dam Association Bulletin - Spring 2018 - Site C Clean Energy Project Diversion Tunnel Orifices for Energy Dissipation During Reservoir Filling
Canadian Dam Association Bulletin - Spring 2018 - 11
Canadian Dam Association Bulletin - Spring 2018 - 12
Canadian Dam Association Bulletin - Spring 2018 - 13
Canadian Dam Association Bulletin - Spring 2018 - 14
Canadian Dam Association Bulletin - Spring 2018 - 15
Canadian Dam Association Bulletin - Spring 2018 - 16
Canadian Dam Association Bulletin - Spring 2018 - 17
Canadian Dam Association Bulletin - Spring 2018 - 18
Canadian Dam Association Bulletin - Spring 2018 - 19
Canadian Dam Association Bulletin - Spring 2018 - 20
Canadian Dam Association Bulletin - Spring 2018 - 21
Canadian Dam Association Bulletin - Spring 2018 - 22
Canadian Dam Association Bulletin - Spring 2018 - 23
Canadian Dam Association Bulletin - Spring 2018 - 24
Canadian Dam Association Bulletin - Spring 2018 - 25
Canadian Dam Association Bulletin - Spring 2018 - Application for 2018 CDA Scholarships
Canadian Dam Association Bulletin - Spring 2018 - 27
Canadian Dam Association Bulletin - Spring 2018 - CDA Presents 2017 Scholarships
Canadian Dam Association Bulletin - Spring 2018 - 29
Canadian Dam Association Bulletin - Spring 2018 - ICOLD Corner
Canadian Dam Association Bulletin - Spring 2018 - 31
Canadian Dam Association Bulletin - Spring 2018 - CDA Conference 2018
Canadian Dam Association Bulletin - Spring 2018 - 33
Canadian Dam Association Bulletin - Spring 2018 - EIC Awards Gala
Canadian Dam Association Bulletin - Spring 2018 - 35
Canadian Dam Association Bulletin - Spring 2018 - 36
Canadian Dam Association Bulletin - Spring 2018 - 37
Canadian Dam Association Bulletin - Spring 2018 - Buyers’ Guide and Trade List
Canadian Dam Association Bulletin - Spring 2018 - cover3
Canadian Dam Association Bulletin - Spring 2018 - cover4
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