Questions continue to swirl as to why the Brown River Dam removal process on Grand Traverse County’s Boardman River resulted in a breach earlier this month.

The breach nearly drained the river above the dam, caused flood-damage to an estimated 53 homes downriver, deposited untold amounts of contaminated sediment downriver and, for some, called into question the wisdom of removing the dam in the first place.

The drawdown of the Brown Bridge Pond occurred on Saturday, Oct. 6. The two engineering firms contracted to remove the dam — AMEC and Traverse City's Molon Excavating — constructed a "dewatering structure" adjacent to the dam to drain the water upstream gradually over two weeks.

"Instead, the entire pond rushed into the river in a few hours, raising the water level five feet and swamping at least 53 properties," according to the Traverse City Record-Eagle.

The Brown River Dam was built in 1921 and is the first of three dams slated for removal on the 26-mile-long Boardman. The dams were originally built to serve the area's logging industry in the nineteenth-century, and hosted hydroelectric generating plants to serve the county's energy needs until the late 1960s.

Opponents of removing the three dams point out that the structures provide necessary flood protection for Traverse City, citing the Boardman (also called Keystone) dam holding back torrential flooding after 10-inches of rainfall in 1961.

The decision to remove the dams has generated significant controversy between the Traverse City, Grand Traverse County and special interests groups on one side and residents of the dam impoundments on the opposing side. Grand Traverse County and Traverse City claim removing the dams will return the river to its original free-flowing state and will better serve residents and attract tourists wishing to fish, canoe and kayak the Boardman.

Opponents assert the process will devastate their waterfront property values and the ecosystems that have evolved between the dams over the past 150 years, including a massive 370-acre nature preserve that was dedicated by the county in 1976, as well as increase the potential for flooding. Additionally, opponents say a rapid flowing river will release toxins released from tanneries and other industries formerly conducting business on the river.

Grand Traverse County health officials warned that wells flooded as a result of the breach might be contaminated, and recommended homeowners boil water before use.

"If the well water was contaminated by chemical toxins from the river sediment, there's no way boiling the water will make it safe to drink," said Bruce Carpenter, a wildlife artist who is also a homeowner on the Boardman Dam impoundment. "Boiling would only kill bacteria and would effectively concentrate toxins such as mercury rather than eliminate them."

Byron Lane, chief of the Hydrologic Studies and Dam Safety Unit at the Michigan Department of Environmental Quality's Water Resource Division, said the DEQ is investigating the cause and impact of the dam breach.

"The city of Traverse City were the applicants for the dam removal permit [issued by the DEQ on Aug. 8, 2012], and I suppose it's a fair statement that it was the city's responsibility to ensure its contractors were in compliance with the permit," Lane said.

The dam removal Implementation Team awarded a $2.9 million contract to AMEC and Molon Excavating to proceed with the Brown River Dam removal. Molon representatives directed this reporter's inquiry to Sandra Sroonian, a senior principal engineer with AMEC. Sroonian directed the call to Charles Lombardo, IT spokesman, who noted the "project team is optimistic the dam removal will still be completed on-budget by the end of this year" and emphasized "it's not really known what caused the breach, whether it was the dam, equipment failure or an individual's fault. It was an unforeseen circumstance," he said.

"Our engineers from the program were onsite for the drawdown and returned to the site to begin their investigation of what caused the uncontrolled drawdown, and we're continuing our investigation," Lane said, adding a DEQ biologist has been investigating the Boardman River downstream from the breeched dam, but not upstream.

In a follow-up email, Lane said: “The investigation of environmental impacts is ongoing but our biologists report that during their survey of the river last Wednesday they observed large deposits of new sediment material seven miles downstream of the dam. That is as far as they have surveyed to date."

Lane said the DEQ's investigation will require a further drawdown of water above the Brown River dam to examine the dam structure. "We have told the city to not disturb the structure itself until our investigation is completed and they receive an OK from us."

Charles Peterson, president of Peterson Machinery Sales, and a property owner on a dam impoundment, had submitted a letter of intent to Grand Traverse County in 2008 offering to return hydroelectric generating capacity to the Sabin and Boardman dams. The county rejected his proposal and moved forward with its dam removal agenda.

"Accidents happen,” Peterson said. "But this accident was entirely preventable. New weight needs to be brought against those groups responsible, and the buck stops with the IT committee, the DEQ and the DNR who all need to be held responsible legally. This is a breach of public trust. These groups have shown that they don't have the control over the situation they assured the public they possessed. This calls into question what's going to happen when the county proceeds with the removal of the next two dams."

Bruce Edward Walker is editor-at-large and former science editor and property rights communications manager for the Mackinac Center.