Questions linger over Lake Manatee Dam release

Joanne Derstine Curphey watched the Manatee River rise on Aug. 5 through three-story plate glass windows at the Christian Retreat, just north of Upper Manatee River Road in Bradenton. 

“It was going so fast,” she said. “We saw boats without anybody in them and docks and all kinds of debris coming down the river.” 

The Christian Retreat property flooded, but Curphey said the housing facility remained dry. Not everyone was so lucky. 

After streets and homes in East County flooded along the Manatee River and along the Braden River in Lakewood Ranch, residents have been questioning the events that led up to 15 billion gallons of water being released from the Lake Manatee Dam during Hurricane Debby, the bulk of which was released on Aug. 5.

Part of those questions stem from an article written by Michael Barfield and published by the "Florida Trident" on Aug. 15. 

The article alleges the county knew the dam threatened public safety; and if water hadn’t been released, the reservoir could have suffered a “catastrophic collapse." The article said the dam is "aging and problem-plagued."

Manatee County added a page to its website, “Hurricane Debby Rainfall and River Information,” that was also published on Aug. 15. It states that the release was necessary to “protect the structural integrity of the dam and our drinking water supply.” 

“Three times the total volume of the reservoir was released during the rain events,” said Bill Logan, a spokesman for Manatee County, in an email. “There is no way that amount of water could be stored in the reservoir. The water was released as needed, and the dam functioned as designed.”

Manatee County Commissioner Mike Rahn spoke with Barfield and is quoted in the article. He said Barfield got it wrong. 

“The dam has probably another good 50 years of life left to it,” Rahn said. “We’re not the only ones who inspect it. The state and the federal government inspect the dam, too.” 

Manatee County has spent $41,887,202 on the dam since 2021 to repair internal erosion and piping that, according to the project sheet, “threatened uncontrolled release of the reservoir if left untreated.” The repairs are on schedule to be completed in December. 

“The construction work on the dam is functionally finished on this project on the downstream primary spillway,” Logan said. “There are some additional repairs needed upstream of the dam, but there is no immediate need for that work at this time.”

Manatee County's staff members added a project to the FY 2025-2029 Capital Improvement Plan to replace the dam’s spillway. The spillway is what controls the release of water. 

The overall project is estimated to cost over $136 million, but the staff requested $17,581,000 be set aside in 2028. Staff is recommending a replacement because past repair attempts have failed. 

East County's Chris McGuinness can see the water treatment plant from his front yard. 

In over 30 years living there, he’s never seen the kind of activity at the plant that he saw on Aug. 5. He saw men in fatigues, helicopters, cargo trucks and Humvees surrounding the property.

He thought the National Guard had come to assist residents, but he said the men only guarded the entrance to the plant. 

“It was very noticeable,” McGuinness said. “The week before, we all knew (the extra release of water) was coming, and I didn’t hear the (spillway) open more than at 6 p.m. when it’s the routine time.”

Normally, he hears the dam open more frequently on a daily basis up to a week before a major storm. He questions why more water wasn’t released ahead of time in preparation for Debby. Since he didn’t hear the extra alarms signaling that water was being released, he didn’t think Debby would cause so much flooding and damage. 

According to the initial situation report on Aug. 3, neither did Manatee County. Director of Public Safety Jodie Fiske wrote that the main threat would be heavy rainfall with storm totals between 5 to 8 inches.

“We had everything ready for a 10-inch rainstorm,” Rahn said. “This thing comes and sits over us for two days and dumps 21 inches of water on us. I think we did everything we could do.” 

Logan wrote in an email that Lake Manatee was, indeed, lowered from 39.5 feet to 36 feet in advance of Debby.

"“This was a massive rain event that simply overwhelmed all of our streams and tributaries," said Charlie Hunsicker, Manatee County's director of natural resources. "In some areas, the rainfall amounts were up to five times greater than the built systems were designed to handle."

Waterline Road resident Mark Vanderee said the county could have done more to be prepared. He wants to see the protocol for reducing lake levels updated to account for the new developments upstream and downstream of the dam. 

Vanderee said by waiting, the county was forced to dump most of the water at the same time a king tide was coming in, and that made all the difference between Debby and past storms.

"You're dumping that much water out of the river and lake upstream of the dam, all the tributaries downstream of the dam have no place to drain, so they're going to back up," he said.

The backed-up Braden River is what concerns residents who live along that river in East County. They believe that contributed to flooding in areas that haven't previously flooded.

Manatee County estimates storm damage at $57 million to homes, including 173 homes with major damage, 89 with minor damage and another 54 homes that were "affected" by the storm.

“The watersheds of these two rivers are separated by their own basin geography and controlled in part by two reservoir dams until they flow together (west of I-75)," Hunsicker said in a county release. "Water released downstream of the Manatee River Dam at Lake Manatee cannot travel upstream to the Braden River and over the City of Bradenton’s reservoir dam into the freshwater side of the Braden River. The dam release did not affect those situations on the Braden River.”

East County residents are not convinced and they have let county commissioners know it. The commissioners have instructed county staff members to initiate a third-party investigation into the response to (the storm) and the recovery.
“That inquiry is already under way,” said Manatee County Deputy County Administrator Evan Pilachowski in a release. “We are gathering data and information from our monitoring points and gauges all over the county to create a complete overview of what happened, when and how.”

The first Lake Manatee water level to be reported on Aug. 3 was 37.88 feet with an inflow of 220 cubic feet per second and an outflow of 1,510 cubic feet per second. 

One cubic foot is equal to about 7.5 gallons of water. As noted in one of the situation reports, water flowing out of the dam at less than 3,500 cubic feet per second has no effect downstream. 

By Aug. 4 at 8 a.m., the county had lowered the lake level to 36.1 feet, but it rose to over 41 feet the following day because of the storm. 

Before 5 p.m. on Aug. 5, the water flowing into the reservoir was about 60% more than the water flowing out. 

During the rainy season, the standard operating procedure is to release what comes into the lake to keep the lake level at 38 feet because that keeps the water level under the plugs.

There are 11 plugs within the emergency system that dissolve on their own when the water rises too high. 

Logan said three plugs were dislodged during Debby. A backhoe removed the first one. The second one eroded as the backhoe was attempting to remove it, and the third dissolved as it was designed to do. 

“The question in my mind is 'Did that need to happen (Lake Manatee rising to a level where the plugs were needed)?'” Commissioner George Kruse said. “Were there steps that could have been taken, based upon a reasonable expectation from people with enough experience, to have avoided that necessity?”

Kruse said the Inspector General should take over any study of the county's reaction to the storm because that office has no vested interest in looking good at the end of the report.