Watch your step: People are removing manhole covers when streets flood in Miami

When Miami-Dade County’s mayor stepped to the microphones Tuesday with a plea for residents to prepare for Hurricane Ian flooding, the first topic she mentioned was manhole sabotage.

“You can help. Each and every one of you,” Mayor Daniella Levine Cava said at a press conference in the county’s Emergency Operations Center in Doral. “By keeping the manhole covers closed. Do not pry them open.”

County water managers partly blame missing manhole covers for a sewage spill into Biscayne Bay during a tropical downpour that hit Miami-Dade in June.

Faced with flooded streets, parking lots and even backyards, some people allegedly created makeshift and illegal drains with the county’s sewer system. Removing the mostly watertight metal discs gives the rainwater a place to go but also can inundate sewage pipes leading to sewer facilities that can only handle so much water.

“Our team probably found a dozen that were removed,” Roy Coley, the county’s Water and Sewer director, said of missing manhole covers after the tropical system that soaked Miami-Dade in the first week of June. “One open manhole can flood out a whole system. With a dozen of them open, it’s totally flooded.”

Water and Sewer doesn’t track open manhole covers, and a spokesperson said the agency couldn’t provide a list of where the covers were breached in June. Coley said at the time multiple missing manhole covers were discovered in downtown Miami.

READ MORE: The water ‘has no place to go.’ Cutler Bay streets flooding as rain continues to fall

Coley also said manhole flooding was only one element that led to a failure at Miami-Dade’s Virginia Key sewage treatment plant on June 4, which sent about 750,000 gallons of sewage into the bay and prompted several days of no-swim advisories.

Leaky sewer pipes can also help overwhelm sewage plants during heavy rain, with groundwater seeping into the sewer system. Equipment failures or maintenance keeping pumps and other machinery off line have led to sewage spills in the past, but agency spokesperson Jennifer Messemer-Skold said the Virginia Key plant was operating properly when the deluge hit.

“There was no equipment or process failure at the plant during the June 4 storm,” she said Tuesday. “It was a capacity issue. Too much rainfall in too short a period of time for our plant to be able to accommodate.”

READ MORE: ‘I have no parts for these pumps.’ The anatomy of a sewage spill in Miami-Dade County

Miami-Dade’s code prohibits “tampering with utility fixtures,” a civil offense that can bring fines up to $1,000. Loose or missing manhole covers also produce hazards, with the possibility of someone stepping into a pit that can lead to a drop nearly two stories below.

“It creates a major safety issue,” said Miguel Sorria, assistant director of Miami-Dade County’s Transportation and Public Works Department, which manages the storm-water system.

The county’s storm-water system, along with municipal systems inside city limits, are designed to collect rainwater into underground pipes and run-off areas into canals. Those eventually flow into Biscayne Bay and underground aquifers that supply drinking water.

During heavy rain, the ground can become saturated enough that drainage systems no longer function. High tides can back up stormwater outlets linked to the bay. And clogged drains and malfunctioning pumps can also lead to failures.

With the National Weather Service expecting Hurricane Ian to drench Miami-Dade through Thursday with up to 6 inches of rain, county administrators are preparing for flooded streets and stormwater challenges. In her press conference, Levine Cava suggested residents reduce water usage during peak times in the morning and evenings to relieve pressure on the sewer system.

Even so, that may not lead to the spree of manhole removals Miami-Dade saw in June. Josiel Ferrer-Diaz, chief of operations and maintenance in Public Works, said the June tropical system brought as much as 12 inches of rain in a single 24-hour period. He said the county’s forecasts are predicting up to 10 inches from Ian through Thursday.

“Ten inches over three days is something our system should be able to handle,” he said.