The Coquitlam watershed is the largest of the three Metro Vancouver watersheds having an area of 20,461 hectares. It is north of the city of Coquitlam, east of Indian Arm and Buntzen Lake, and west of Coquitlam Mountain. Coquitlam Lake, a natural lake, is the reservoir for the Coquitlam watershed. It receives inflow of water from the Coquitlam River whose headwaters are situated north at Disappointment Lake. Many creeks and streams drain into the Coquitlam River and Coquitlam Lake from the surrounding mountains. Coquitlam Lake was dammed in 1905 by the BC Electric Railway Company. The Coquitlam River extends south of the dam, passing through the Coquitlam Town Centre and eventually meeting the Fraser River.