Flooding in Cheraw (copy)

Some homes in lower lying areas of Cheraw in the Pee Dee had significant flood damage in the wake of Hurricane Florence in September. Andrew Brown/Staff

During the worst of Hurricane Florence, the Great Pee Dee River dumped more than a half-million gallons of water — enough to fill a 5-foot-deep swimming pool the size of a football field — every single second.

It was the largest flow ever recorded at the river's stream gauge at Galivants Ferry. It was also among 10 record flows in the state, along with 10 flood depths that also broke records.

The numbers were released in a preliminary study released Tuesday by the U.S. Geological Survey. All 84 gauges surveyed in South and North Carolina— where the heaviest rain fell — had flow or flood totals in the top five highest. In all, 28 records were set.

"One thing we discovered while compiling this report was many of the new peaks of record set by Hurricane Florence broke previous records set by Hurricane Matthew in 2016,” said Toby Feaster, USGS hydrologist and lead author of the study.

“Since several of the stream gauge sites we analyzed had more than 30 years of historical data associated with them, it was interesting that a majority of the No. 1 and 2 records were from back-to-back flooding events,” he said.

The study will join other analyses the S.C. Emergency Management Division is reviewing in the wake of the Florence, officials said.

The swath of flooding was so widespread South Carolina is still digesting what it might mean for future storm preparations. More than 20 inches of rain fell in some spots in South Carolina alone.

Florence additionally intensified concerns in the Charleston area already affected by back-to-back years of river overflows, the historic flood associated with Hurricane Joaquin in 2015 and Matthew in 2016.

Nearly all the flooding was to the north of the city. But a nudge of steering winds was all that kept the storm from swamping Charleston-area rivers, too.

"Any time it rains you have a different feeling," said Bill Cahill, of Huger, who lives off French Quarter Creek in Berkeley County.

The heaviest rains from Florence to approach Charleston fell within 20 miles of the creek. The 2015 flood swallowed homes there to the point that the National Guard airlifted some residents.

In Hurricane Florence, agencies such as USGS gave the Emergency Management Division some of the best predictions the division ever had, said Director Kim Stenson, helping residents make their evacuation decisions more quickly.

"We’ve found no systemic issues with the state’s emergency management program both locally and statewide. We will continue to refine our emergency plans based on best practices and lessons learned as we review the entire response to Hurricane Florence and the ongoing recovery efforts, ” Stenson said.

At a minimum, more stream gauges are needed to augment the 192 in place across South Carolina, said John Shelton, USGS associate director for data.

"The need for additional monitoring stations has been evident four years in a row: Joaquin, Matthew, Irma and Florence (hurricanes or tropical storms). Efforts need to be focused on preparing rather than reacting," he said.

"Rain from Hurricane Florence set a new state record for precipitation from a tropical event. These extreme events seem to be becoming the norm rather than the exception," Shelton said.

Reach Bo Petersen Reporter at Facebook, @bopete on Twitter or 1-843-937-5744.

Science and environment reporter. Author of Washing Our Hands in the Clouds.