While the best-case scenario for the Lake Alice dam breach is to have the repairs handled within a year, the issue likely is far from over.
Residents living on or near the Lake Lanier cove clouded by sediment and debris since the May incident expect the focus to shift to other mitigating factors — largely the continued retail development along the Market Place Boulevard corridor.
When Jim Hixon moved to his lakefront home the Market Place area “used to be farmland.”
Over the years, however, it has steadily evolved into a retail hub. Hixson said as new development opens, more and more silt enters the cove, which is shared by about 50 residents.
He cites water runoff from an area extending by where Market Place meets Highway 20, east to where a new car dealership is going in, and “all the way through to down here was going into Lake Alice.”
“Now it’s covered in impervious surface and so the water has to come somewhere,” he said.
Hixson blames the dam collapse on all the development without “allowing for adequate runoff protection.” And he’s not alone.
Michael Carvalho, attorney for the Mashburn family trust, which owns the dam, said it was overtopped.
“And that was a direct result of the dramatic increases in stormwater entering into Lake Alice, which are a direct result of the development around Lake Alice,” Carvalho said. “The development has had a dramatic impact on the watershed that resulted in the Lake Alice Dam overtopping.”
Carvalho’s information comes from a Golder Associates study the family commissioned to investigate the cause of the dam break.
The study shows commercial development from 1992 to 2010 grew from 41 to 295 acres. During that span, there was a decrease of nearly 200 acres of wooded area, as well as residential land dropping from 108 to 34 acres.
The study shows predevelopment conditions produced a high water elevation of nearly 2 feet less than conditions in 2010, which the survey said was just enough to overtop the dam.
The city, which reached an agreement with the family this week to assess the damage from the dam breach and come up with a solution to the issue, received results of the study last week.
Through its attorneys at Miles Patterson Hansford Tallant, Cumming released a statement Wednesday saying it was “confident that the cause of the dam failure is not related to any city activities, but rather was the result of an unprecedented season of rainfall combined with one particularly heavy rain event over an extremely short period of time that directly impacted Lake Alice.”
According to both the study and Carvalho, further assessment is needed, specifically involving stormwater detention, as well as the lake and watershed stormwater controls.
Still, Carvalho said he’s convinced the 4.4 inches of rain shown by the study to have occurred in the 48-hour period on May 18 and 19 was not enough to overtop the dam that was built more than 70 years ago.
In addition to the Mashburn family, two cove residents are working with attorneys.
Hixson said while he’s not party to a potential lawsuit, he’s siding with his fellow residents.
“I think people should come together and take responsibility,” he said. “They made that soil impervious and they did not allow adequate runoff protection, so when the lake reached that point, the dam burst.”
“Lake Alice dam was holding back a lot of water ... and Sanders Road is basically a dam with a 36-inch hole in it.”
In its statement, the city contends it “does not admit to any liability or responsibility for the failure of the Lake Alice Dam.”
“There has been an effort to try and blame the city for the failure of the Lake Alice dam. It is truly unfortunate that such efforts to pass blame have been put forward when the focus should be on remediation, and the city declines to engage in similar activities,” the statement said.
“Instead the city of Cumming will remain focused on working with the Georgia [Environmental Protection Division] and the [U.S. Army] Corps of Engineers on the resolution of the impact from the failure of the dam.”