Town in catastrophe’s path?

More than 1 billion gallons of contaminated water -- enough to fill about 1,500 Olympic-sized swimming pools -- is trapped in a mountain tunnel above the historic town of Leadville and threatening to blow.

Lake County commissioners have declared a local state of emergency for fear that this winter’s above-average snowpack will melt and cause a catastrophic tidal wave.

The water is backed up in abandoned mine shafts and a 2.1-mile drainage tunnel that has partially collapsed, creating the pooling of water contaminated with heavy metals.

County officials have been monitoring the rising water pressure inside the mine shafts for about two years. An explosion could inundate Leadville and contaminate the Arkansas River.

“It could come out. We just don’t know where,” County Commissioner Carl Schaefer said. “We’re seeing changes and we’re very concerned. We’re not crying ‘Chicken Little’ here.”

State and federal officials agreed last week to conduct a risk assessment before taking action. Critics said something should be done immediately to relieve the pressure.

Peter Soeth, a spokesman for the Bureau of Reclamation, which acquired the drainage tunnel in 1959, said there was no immediate threat to Leadville’s 2,700 residents.

The tunnel normally drains water that seeps into some of the hundreds of abandoned mine shafts and other workings in the mountains east and south of Leadville and deposits it into the East Fork of the Arkansas River about a mile north of town.

The Environmental Protection Agency raised concerns about the situation in letters to the Bureau of Reclamation. “Due to the unknown condition of the tunnel blockage and the large volume of water behind the blockages, we are concerned that an uncontrolled, potentially catastrophic release of water to the Arkansas River from [the tunnel] is likely at some point,” said one EPA letter sent in November.

Stan Christensen, an EPA expert on the tunnel, said the likelihood that something catastrophic could happen increases the longer nothing is done.

A water treatment plant at the foot of the tunnel removes toxins and heavy metals such as zinc, cadmium and manganese before discharging the water into the Arkansas River.

New springs and seepages have appeared at California Gulch, which sits below the plant.