TALLAHASSEE — Heavy rainfall over North and Central Florida from Hurricane Irma has swelled 23 rivers and creeks to beyond flood stage Wednesday, threatening homes along their banks and potentially forcing a massive re-routing of drivers along I-75, state officials warned.
According to water level sensors maintained by the U.S. Geological Survey, the biggest threat appeared to be the Santa Fe River, which stretches 75 miles through the heart of the state in northern Florida. The river was recorded at 56,39 feet on Wednesday, according to the USGS gauging station, and is 13 feet above flood stage estimates of the National Weather Service.
What's worse: the water is still rising and is expected to continue through the weekend, as water levels from upstream move southward down the river, the agencies said.
The USGS is working with the Florida Department of Transportation to monitor the safety of a small bridge on I-75 at mile marker 408 crossing the Santa Fe River on the northern border of Alachua County.
FDOT said in a statement that the interstate, clogged with evacuees from the storm trying to return home to South Florida, is still passable. But, they warned, the river levels could rise and force them to close the bridge and re-route traffic, creating even more headaches for the road weary.
Because the USGS monitoring station of the Santa Fe River at O'Leno State Park is inaccessible due to the flooding, FDOT and the Florida Highway Patrol controlled traffic Wednesday morning to allow USGS engineers Mark Stephens and Joshua Sundberg to measure the river levels from the shoulder of the highway, said Mark R. Dickman, one of the agency's hydrologic data section chiefs in its Davie office.
"We were informed that if the water level reached 58 feet they would have to shut down this stretch of the interstate and reroute traffic," he said.
The measurements will be used to help the NOAA Southeast River Forecast office to help emergency managers forecast the river's peak and help with decisions concerning road closures in the area.
According to the USGS real-time water monitors, situated in dozens of waterways across the state, six other rivers that were already at flood stage in Florida continued to rise Wednesday, and 17 others that are at flood stage had leveled or dropped in the last day.
Santa Re River is at 56.39 feet, above the flood stage of 43 feet, and is projected to continue rising.
Ocklawaha River at Eureka is three feet above flood stage and still rising.
The Peace River is swelling in several places. At the USGS monitor in Bartow, it was more than a foot above flood stage and was rising Wednesday. In Arcadia, the river measured seven feet above flood stage and had risen since Tuesday, but, between those monitoring points, the river was five feet above flood stage at Zolfo Springs. It had dropped slightly since Tuesday.
Cypress Creek at Worthington Gardens is nearly three feet above flood stage and continues to rise.
The Withlacoochee River at Croom, east of Tampa, continues to rise and is at flood stage of nine feet. Further south at Trilby, the river is two feet above flood stage and rising.
The St. John's River at Astor, south of St. Augustine, is two feet above flood stage and is rising. At DeLand, northeast of Orlando, the river is less than a foot above flood stage but continues to rise. In Cocoa, the St. John's is at flood stage and continues to rise.
The Little Wekiva River near Altamonte Springs is slightly below the 30-foot flood stage and on Wednesday appeared to level.
There is good news, however, in other parts of the state.
The Hillsborough River at Morris near Thonotosassa is nearly two feet above flood stage and continues to rise. Further north near Zephyrhills, however, the river was recorded at 3.7 feet above flood stage early Wednesday but has dropped since Tuesday.
The Manatee River continues to drop. At the monitor point near Sarasota it was at 2.8 feet above flood stage and at the Myakka Head monitor, it remained at flood stage of 11 feet but dropped dramatically from the 18 feet it reached Monday.
The Alafia River at Lithia, east of Tampa, was 11 feet above flood stage Wednesday but had dropped more than a foot since Tuesday.
The Anclote River, near Elfers, north of Clearwater is at four feet above flood levels and but has dropped since Tuesday.
The North Fork of Black Creek at Middleburg, west of Jacksonville, crested at 30 feet Tuesday and has since dropped to 21 feet, still above the 14-foot flood stage.
The St. Mary's River near Macclenny, west of Jacksonville, remains at 11 feet above flood stage but has dropped slightly since Tuesday.
The Suwannee River at White Springs, west of Lake City, is at flood stage of 76 feet and leveling.
Fisheating Creek in Palmdale, in Glades County, was more than three feet above flood stage and appeared to be leveling.
The Ocklawaha River at the Rodman Dam near Orange Springs is four feet above flood stage but has dropped almost a foot since Monday. Farther south, in Ocala, the river is also at flood levels but is also dropping.
Deep Creek at Spuds, a community in St. John's County, is still nearly three feet above flood stage but has dropped two feet since Monday.
Contact Mary Ellen Klas at email@example.com. Follow @MaryEllenKlas