Withlacoochee River Conditions Update - 8/12/2024

Update on Withlacoochee River Conditions

 

River levels are still rising in most areas and the Withlacoochee could reach flood stage in the coming weeks at certain locations, depending on future rainfall.

 

Note: In the update below, I’ve included links to the USGS gauge conditions so you can keep an eye on what the river is doing in different areas.

 

Little Withlacoochee River (Sumter/Hernando Counties):

• The Little Withlacoochee River at US 301 remains in minor flood stage.
• River levels crested last Wednesday (8/7) and have dropped about a foot over the past 5 days.
• The Little Withlacoochee River continues to slowly drop but could rise again if the area receives heavy rainfall.

 

 

Withlacoochee River (Green Swamp to the Gulf of Mexico):

 

Green Swamp

• The Withlacoochee River at SR471 in the middle of Green Swamp is increasing again.
• River levels had peaked last Wednesday, but heavy rainfall in the Green Swamp over the weekend has the river rising once again.
• At the Dade City gauge on the west side of the Green Swamp, river levels are close to their peak last Friday, but expected to rise again in the coming days.

 

Trilby and Ridge Manor

• Downstream of the Green Swamp, the Withlacoochee River’s floodplain narrows, and all the flow is forced between high banks near Lacoochee and Trilby. Because of this natural topography, the river can rise very high here.
• The Withlacoochee River at Trilby (US301) has already risen nearly 7 feet over the past week and continues to rise. Over the last 24hrs, Trilby rose 11 inches.
• The National Weather Service is now predicting Trilby to come within 6 inches of minor flood stage by this weekend.
• At this point it is unknown when Trilby will peak, with levels currently 7.2 feet lower than the peak of Hurricane Irma in 2017.
• Near Ridge Manor (SR50) the river has also risen 11 inches in the past 24hrs and continues to rise sharply.
• Currently, river levels there are about 7 feet lower than the peak in 2017 (Irma) but will continue to rise for at least the next several days.

 

Nobleton and Hwy 48

• Downstream of Silver Lake, the river’s floodplain widens again, and river levels don’t fluctuate as drastically as they do near Trilby and Ridge Manor.
• At Nobleton (CR476), the Withlacoochee River also continues to rise from rainfall associated with Hurricane Debby.
• The river has already risen 2.5 feet in the past week, including about 2 inches in the last 24hrs.
• The Withlacoochee at Nobleton is currently about 2 feet lower than the peak from Hurricane Irma (2017) but is expected to continue to rise for at least another week.
• At Hwy 48 (between Floral City and Bushnell), river levels are also still rising and likely won’t peak for at least another week or two.
• River levels at Hwy 48 are currently 2.5 lower than the peak from Hurricane Irma in 2017.

 

Wysong, Lake Panasoffkee, and Tsala Apopka Lake Chain

• The Wysong structure is now completely lowered as river levels/flows continue to increase.
• The boat barriers (orange buoys) should be removed this week, allowing boat traffic to pass over the Wysong structure while levels remain high.
• Lake Panasoffkee remains at a high level due to strong flows entering the lake from Shady Brook and Little Jones Creek.
• As of now, no river flow is entering the Tsala Apopka Chain of Lakes as crews work to expedite construction at the Golf Course Structure.

 

Hwy 44 and Hwy 200

• River levels continue to slowly rise at Hwy 44, a trend that will likely continue for the next couple weeks.
• At Hwy 200 (Holder), where river levels can rise substantially due to a narrow channel and high banks, the Withlacoochee is also still rising.
• Currently river levels are about 4 feet lower than the peak from Hurricane Irma.
• How high the river will rise at Hwy 200 is difficult to predict, but it will continue to rise for the next few weeks at least.
• The National Weather Service is not showing any flood predictions yet for Hwy 200, because its too far out, but I recommend monitoring the forecast site for this location over the next couple weeks.

 

Dunnellon and Lake Rousseau

• At Dunnellon (Hwy 41), the Withlacoochee River is back down below flood stage, but remains about 8-12 inches above is normal level.
• The Inglis Dam remains open, keeping the west end of Lake Rousseau lowered about 7 inches below normal.
• This also helps keep Dunnellon below flood stage by discharging excess water from Lake Rousseau into the Gulf of Mexico.
• Once the threat of high water at Dunnellon passes, Lake Rousseau will return to its normal level.
• Keep in mind, the Inglis Dam has no effect on river levels upstream near Hwy 200. Any flooding in that area, or farther upstream, is caused by natural river conditions.

 

Lower Withlacoochee River

• The Inglis Bypass Spillway also remains fully open, discharging maximum flows to the Lower Withlacoochee River.
• The Lower Withlacoochee is back to its normal tide cycle.

 

 

Have a great week and I’ll do my best to keep you updated.

 

-Mark

 

 

 

Mark Fulkerson, Ph.D., P.E.

Chief Professional Engineer

Southwest Florida Water Management District

 (352) 269-6073 (office)

(352) 279-4493 (cell)

Mark.Fulkerson@WaterMatters.org

 Withlacoochee River Watershed Initiative