Coquitlam Dam Seismic Upgrade Project ... - BC Hydro

1. INTRODUCTION
1.1. PROJECT OVERVIEW
Coquitlam Dam Seismic Rehabilitation
ENVIRONMENTAL MANAGEMENT PLAN
Version 4
The Coquitlam Dam is located on the Coquitlam River 15 km upstream from its confluence with
the Fraser River, as shown on Figure 1. The original dam was constructed to provide additional
storage and flow for the Buntzen Lake Generating Station. The Coquitlam Reservoir also
supplies drinking water to the Greater Vancouver Regional District (GVRD) via an intake and
tunnel on the eastern shore of the reservoir.
The Coquitlam River and Coquitlam Lake Reservoir also hold historical and cultural
significance for Kwikwetlem First Nation. BC Hydro is consulting with them directly in regard
to this project.
The Coquitlam Dam is a hydraulic earthfill embankment with a crest length of 290 m and a crest
elevation of 161.4 m. Facilities also include:
• an overflow spillway;
• an outlet tunnel which has been converted to a three-gate low-level sluice at el. 140.23
m;
• fish flow release valves (el. 140.76 m), which also convey water through the outlet
tunnel; and
• the Coquitlam-Buntzen tunnel at el. 132.0 m, which conveys water from Coquitlam
Reservoir into Buntzen Lake where it is stored for power production at the Buntzen
generating Station located on the east shore of the Indian Arm of the Burrard Inlet.
GVRD facilities include a drinking water intake structure at el. 132.65 m, a supply line
conveying water through the left abutment of the dam to the watermain located downstream and
a valve house located immediately downstream of the dam.
1.2. PROJECT BACKGROUND
Coquitlam Dam, as shown on Figure 2, was originally constructed to replace a smaller dam built
on the site in 1903. The dam was seismically upgraded in 1980 and 1984/85 by placing
buttressing fills on the upstream and downstream slopes. Studies completed in 1998/2000
Coquitlam Dam Seismic Rehabilitation Page 1
Environmental Management Plan – Version 4
June 15, 2004