Before we explore how long it took to close the Bly Tunnel, I hope whoever reads this, closely examine the above photograph. The tunnel was in its early stages of construction. If one looks closely, you can see the lake level has already dropped, though it would be another two years before water flowed through the tunnel.
By the late 1960s, no one really paid that much attention to the abandoned Bly Tunnel at Eagle Lake. By 1970, the level of lake kept rising, threatening some lake shore improvements. In November 1971, D. Dean Bibles, District Manager of the Susanville Bureau of Land Management (BLM) announced that it would take action to revoke the Bly Tunnel right-of-way which was on BLM lands. Bibles noted that there were would be public hearings on the process. He noted there were some that wanted to keep the tunnel open to stabilize the lake level. There was the other camp, that wanted to permanently seal the tunnel to allow the lake level fluctuate naturally.
On February 6, 1973, BLM gained control of the Bly Tunnel for lack of non-use and water rights. The following year, BLM declared the tunnel a safety hazard. At that time, the BLM had the tailing piles used to make a temporary plug of the inlet, which greatly reduced water flow into the tunnel.
In 1981, Murrer Ranch filed a quiet title action over the granted right-of-way for a canal for distribute the water from the tunnel. After all, this is was first water connection from the tunnel. The following year, Murrer’s neighbor, Barron Ranch also filed a quiet title action, thus rendering project as done. In 1986, BLM had a permanent concrete plug constructed at the inlet.
However, water still flowed through the tunnel. In 2011, a valve inside the tunnel to regulate flow was finally shut and the water stopped flowing. While the tunnel was originally somewhat functional for a period of eleven years, it took BLM forty years to close it.