A year and a half of construction time and $53 million later, Ameren is completing the finishing touches on its project to reinforce Bagnell Dam.

A year and a half of construction time and $53 million later, Ameren is completing the finishing touches on its project to reinforce Bagnell Dam.

The first major structural update of the clean energy source in more than 30 years, the project to enhance dam safety is finishing a little ahead of schedule, originally slated to be done in the fall.

Ameren Missouri secured the dam with new anchor points and concrete within the dam’s structure on the downstream side. In 2017 it produced more than 624,000 megawatt-hours of energy, enough to supply approximately 52,000 homes for the year.

Ameren officials are confident that this work will improve theintegrity of the 85-year old structure for many decades to come.

"For nearly a century, the Bagnell Dam has reliably powered homes and businesses across the region,” said Warren Witt, director of hydro operations at Ameren Missouri. “These upgrades ensure the dam will continue to be a top producer of clean, renewable energy for Missouri’s communities for the next 100 years.”

Witt says that the process to complete the work was divided into four main segments.

Beginning work in March 2017, the crew installed new anchor points along the dam that more securely stationed it into the bedrock below. Sixty-seven holes were drilled 75 feet into the bedrock to house the metal anchors and firmly sit the foundation. These anchor now provided two million pounds of tension to the structure. This was the main project among the entire set of construction.

New technology installed with the new anchors, which are mechanically tightened and sealed, will allow them to be unsealed and tightened in future years as needed.

The last major structural update at Bagnell Dam was completed in the late 1980s when 277 post-tension anchors were installed to hold the dam into the bedrock. The anchors were the best technology at the time and have performed well since they were installed, according to Ameren Missouri. However, officials understood at the time that the 1980s-era anchors would not hold forever due to corrosion.

That wasn’t occurring yet, but according to Ameren, they won’t hold another 100 years, necessitating the current project.

For additional stabilization, construction crews needed to simply add more total weight to the dam. Concrete was poured between the piers below the main roadway. Once dried, the concrete added around 66 million pounds of weight to the structure.

A smaller project included increasing weather resistance to the existing concrete in order to better the overall quality. Crew members spent time blasting off inches of existing, poor quality concrete in order to lay a new set that will be more capable of withstanding poor conditions throughout the year.

The final step, which Witt says is rarely see by the common spectator, was new drains drilled in. These drains are positioned at the base of the bedrock below the dam. These are used to allow for the removal of any water that may try to move under the dam and cause up-lifting. Witt says these drains move the water directly into the river and are crucial to long-term structural integrity.

Before construction began, Ameren Missouri hired Missouri-based MC Industrial as the project’s on-site general contractor. Plans were reviewed and certified by independent engineers as well as the federal government.

“The Lake of the Ozarks is beloved by residents and tourists alike – and we wanted to be sure our project wouldn’t impede enjoyment of the lake or surrounding areas,” said Witt. “We are grateful to the Lake community and its visitors for their flexibility and patience as we complete this significant project to continue to ensure clean, reliable energy to our customers.”

During the first 16 months of the project more than 220 construction jobs were created for the local trades and vendors in the area, according to Witt, translating to an estimated $40 million impact on the region through additional spending.

As part of Ameren’s Federal Energy Regulatory Commission license they’re required to conduct regular safety inspections. In addition to daily, weekly and quarterly inspections by Ameren experts, Bagnell Dam is inspected annually by an independent safety engineer.

Bagnell Dam was originally completed in 1931.