The first Coquitlam Dam, built to raise the water level of Coquitlam Lake by five feet, was begun in April 1904, and completed in 1905. It was built to protect the water supply to powerhouses on Indian Arm, via a tunnel to Buntzen Lake, and also supplied water to New Westminster. By 1906 the original dam was discovered to be leaking, and while repairs were made the leak continued through 1908, until a second dam was completed in 1914. At the time of the tunnel's completion, it was the longest power diversion tunnel in the world. Due to seismic concerns, an embankment dam was built on the downstream side of the original rockfill dam in 2008.