Hurricane Ian may drop as much rain on Central Florida as during a typical summer month, the National Hurricane Center is warning.
But the center also hedged its prediction: local downpours may be greater than expected.
Anticipating a deluge, the City of Orlando said Monday it would drain as much as a foot of water from lakes Ivanhoe, Concord, Adair, Lurna, Greenwood, Davis, Spring, Cherokee, Rabama, Eola and Lancaster.
City spokesperson Ashley Papagni said lower levels should take as many as two days.
The National Weather Service is forecasting that rainfall chances will jump to 70% to 80% by daybreak Tuesday and remain in that range until nightfall Thursday, when potential will begin to taper off.
The St. Johns River Water Management District, a state agency that monitors and manipulates waters in much of Central Florida, reported that its dams and flood controls in the upper reaches of the St. Johns River south of Orlando have enough capacity to hold Ian’s forecasted precipitation.
The St. Johns district’s forecasts call for about 6 inches of rain in Orange and Osceola counties, 8 inches in Volusia County’s interior and in south Brevard County, 10 inches in Marion County, more than 11 inches in coastal Flagler County and nearly 10 inches in the Gainesville area.
But the water district also warned that it has no means to regulate ditches, canals, rivers and runoff within much of the Orlando area. Property owners should deal now with expected rains by getting debris out of storm drains and ditches and reporting clogged ditches to local governments, the agency said.
Jeff Charles, a project manager with Orange County’s stormwater division, said crews have been inspecting 95 miles of canals, 74 wells that drain excess waters into underground aquifers and pump stations.
“We’re preparing all year long to be honest with you,” Charles said. “All year long we’re actually doing maintenance so we’re ready for storms, as ready as we can be.”
Seminole County government began to issue sandbags last week not only because of Ian’s approach but also because of recent heavy rains taxing drainage systems.
The city of Orlando also reminded residents to be wary of power outages and their impacts to sewage handling, including to electric pump or “lift” stations that force wastewater through pipelines to treatment plants.
“If a resident loses power they should assume there is a potential that the lift station that serves their residence may have also lost power,” Papagni said.
Orlando and other local governments generally urge residents to limit flushing and showers until power returns or until they know that their sewage system is still operable.
Local governments routinely equip many but not all lift stations with emergency generators.
Hurricane Irma in 2017 brought power outages and flooding to much of Florida’s peninsula. Sewer systems were overwhelmed by the loss of power and by storm water that invaded manholes and sewer pipes, making it all the more difficult to handle sewage flows.
The South Florida Water Management District, responsible for waters spanning from south Orlando, through Osceola County and down through the the Miami area, is warning that the rain in Osceola County could cause the Kissimmee River to flood.
But the district’s executive director, Drew Bartlett, said staff is prepared to respond to Ian.
“We are all ready for this storm, we are all preparing for it,” Bartlett said. “That’s from scientists to control room operators to permit compliance folks to field operations centers. We are all banding together to make sure we can manage this storm.”
Steve Hudak contributed to this story. kspear@orlandosentinel.com
