Hurricane Debby Rainfall & River Information

Posted on 08/15/2024
Braden River at River Club Blvd Station Stage Reporting:

Max Stage 19.62 ft @ 18:00 08/05/24

Notes:  Max Stage surpassed 100-year flood stage 18.26 ft. Stage referenced with respect to North American Vertical Datum (NAVD)

Braden River at River Club Blvd Station Rainfall Reporting:

Event Rainfall Total:  14.02 inches

Note:  Hurricane Debby Event Rainfall Accumulation Total (04:00 08/03/24 – 04:00 08/06/24)

24-Hour Rainfall Maximum Total:   11.57 inches (08:00 08/04/24 – 08:00 08/05/24)

Note:  NOAA Atlas 14 Storm Frequency:  Surpassed 50-year (10.20 inches); Below 100-year (12.00 inches)

48-Hour Rainfall Maximum Total:   13.49 inches (08:00 08/04/24 – 08:00 08/06/24)

Note:  NOAA Atlas 14 Storm Frequency:  Surpassed 50-year (12.00 inches); Below 100-year (14.20 inches)

Station Location (Refer to Attached Snippet):

Google Map - Braden River at River Club Station

Braden River at 44th Avenue East Station Stage Reporting:

Max Stage 4.10 ft @ 14:45 08/05/24

Notes:  Combination Storm Surge and Flood Inundation.  Max Stage surpassed 100-year flood stage 18.26 ft.  Stage referenced with respect to North American Vertical Datum (NAVD)

Braden River at River Club Blvd Station Rainfall Reporting:

Event Rainfall Total:  12.44 inches

Note:  Hurricane Debby Event Rainfall Accumulation Total (04:00 08/03/24 – 04:00 08/06/24)

24-Hour Rainfall Maximum Total:   9.86 inches (08:00 08/04/24 – 08:00 08/05/24)

Note:  NOAA Atlas 14 Storm Frequency:  Surpassed 25-year (8.77 inches); Below 50-year (10.40 inches)

48-Hour Rainfall Maximum Total:   10.57 inches (08:00 08/04/24 – 08:00 08/06/24)

Note:  NOAA Atlas 14 Storm Frequency:  Surpassed 25-year (10.30 inches); Below 50-year (12.20 inches)

Station Location (Refer to Attached Snippet):

Google Map River Club Braden River 2

Hurricane Debby Event Rainfall Accumulation Totals (04:00 08/03/24 – 04:00 08/06/24)

Note: Stage referenced below with respect to North American Vertical Datum (NAVD).

Aztec Cove @ DeSoto Memorial Highway Station:

Max Stage 2.80 ft @ 12:15 08/05/24 (Storm Surge)

Rainfall Total: 9.07 inches

Bowlees Creek at 44th Avenue East Station:

Max Stage 27.73 ft @ 02:15 08/05/24

Rainfall Total: 9.88 inches

Bowlees Creek at 63rd Avenue East Station:

Max Stage 12.99 ft @ 05:30 08/05/24

Rainfall Total: 11.40 inches

Bowlees Creek at Magellan Drive Station:

Max Stage 4.57 ft @ 02:00 08/05/24 (Combination Storm Surge and Flood Inundation)

Rainfall Total: 10.22 inches

Braden River at 44th Avenue East Station:

Max Stage 4.10 ft @ 14:15 08/05/24 (Combination Storm Surge and Flood Inundation)

Rainfall Total: 12.44 inches

Braden River at River Club Blvd Station:

Max Stage 19.62 ft @ 18:00 08/05/24

Rainfall Total: 14.02 inches

Buffalo Canal at Fort Hamer Road Station:

Max Stage 29.67 ft @ 05:15 08/05/24

Rainfall Total: 8.45 inches

Canal Drain at 17th Street West Station:

Max Stage 9.81 ft @ 11:00 08/05/24

Rainfall Total: Not Reporting

Carr Drain at 17th Street West Station:

Max Stage 7.47 ft @ 19:30 08/04/24

Rainfall Total: 9.86 inches

Cedar Hammock South at Bayshore Gardens Parkway Station:

Max Stage 10.27 ft @ 01:30 08/05/24

Rainfall Total: 9.90 inches

Clay Gully Tributary at Clay Gully Road Station:

Max Stage 20.40 ft @ 14:15 08/07/24

Rainfall Total: 9.13 inches

Cooper Creek at University Pkwy.  Station:

Max Stage 19.96 ft @ 21:00 08/05/24

Rainfall Total: 14.36 inches

Coquina Beach Patrol Station:

Max Stage 3.23 ft @ 13:45 08/04/24 (Storm Surge)

Rainfall Total: 7.89 inches

Cow Pen Slough at Lindrick Lane Station:

Max Stage 63.92 ft @ 16:00 08/05/24

Rainfall Total: 13.77 inches

Cow Pen Slough at Panther Ridge Trail Station:

Max Stage 71.47 ft @ 08:45 08/05/24

Rainfall Total: 11.88 inches

Curiosity Creek at Buckeye Road Station:

Max Stage 24.43 ft @ 16:15 08/05/24

Rainfall Total: 9.78 inches

Cypress Strand at Kay Road Station:

Max Stage Not Available - Station Damage

Rainfall Total: Station Damaged

Frog Creek at Buffalo Road Station:

Max Stage 15.08 ft @ 23:15 08/05/24

Rainfall Total: 9.46 inches

Frye Canal at CR 675 Station:

Max Stage 25.78 ft @ 11:15 08/05/24

Rainfall Total: 14.20 inches

Gamble Creek at Jim Davis Rd Station:

Max Stage 21.28 ft @ 21:45 08/05/24

Rainfall Total: 13.93 inches

Gamble Creek at Mulholland Road Station:

Max Stage 3.38 ft @ 00:00 08/06/24 (Combination Storm Surge and Flood Inundation)

Rainfall Total: 13.13 inches

Gap Creek at 45th Street East Station:

Max Stage 7.10 ft @ 10:30 08/05/24 (Combination Storm Surge and Flood Inundation)

Rainfall Total: 12.33 inches

Government Hammock at 60th Avenue East Station:

Max Stage Not Available - Station Not Reporting

Rainfall Total: 9.42 inches

Lake Manatee at Verna-Bethany Road Station:

Max Stage 41.30 ft @ 19:15 08/05/24 \

Rainfall Total: 14.81 inches

Long Creek at Wauchula Road Station:

Max Stage 45.34 ft @ 14:00 08/05/24

Rainfall Total: 8.11 inches

Manatee River at Fort Hamer Park Station:

Max Stage 6.30 ft @ 18:30 08/05/24 (Combination Storm Surge and Flood Inundation)

Rainfall Total: 12.58 inches

McMullen Creek at 28th Avenue East Station:

Max Stage 4.61 ft @ 10:15 08/05/24 (Combination Storm Surge and Flood Inundation)

Rainfall Total: 9.21 inches

McMullen Creek at Bayshore Road Station:

Max Stage 3.22 ft @ 12:45 08/05/24 (Combination Storm Surge and Flood Inundation)

Rainfall Total: 8.32 inches

Mill Creek at Mill Run Station:

Max Stage 23.73 ft @ 11:30 08/05/24

Rainfall Total: 13.46 inches

Myakka City Road Maintenance Yard Station (Rainfall Only):

Rainfall Total: 7.47 inches

Palma Sola Drain at 75th Street West Station:

Max Stage 4.92 ft @ 13:45 08/05/24 (Combination Storm Surge and Flood Inundation)

Rainfall Total: 8.52 inches

Pearce Drain at 63rd Avenue East Station:

Max Stage 14.83 ft @ 11:00 08/05/24

Rainfall Total: 9.77 inches

Pearce Drain at Tallevast Road Station:

Max Stage 15.97 ft @ 14:15 08/05/24

Rainfall Total: 11.76 inches

Public Works Department Station (Rainfall Only):
Rainfall Total: Not Reporting

Rattlesnake Slough at Honore Avenue Station:

Max Stage 6.70 ft @ 11:15 08/05/24

Rainfall Total: 12.92 inches

Slaughter Drain at Erie Road Station:

Max Stage 21.08 ft @ 22:45 08/05/24

Rainfall Total: 9.36 inches

Sugarhouse Creek/Glen Creek at 27th Street East Station:

Max Stage 8.63 ft @ 05:00 08/05/24

Rainfall Total: 8.25 inches

Wares Creek at 9th Street West Station:

Max Stage 12.15 ft @ 01:45 08/05/24

Rainfall Total: 10.06 inches

Wares Creek at 12th Avenue West Station:

Max Stage 3.47 ft @ 02:15 08/05/24

Rainfall Total: 9.89 inches

FAQs

What does Manatee County have to say to those whose homes have been flooded?
Manatee County observed rainfall totals reaching that of 100- and 500-year levels. This substantial amount of rainfall led to widespread flooding in many areas, some of which had never experienced flooding in the past.

What caused the flooding at Lakewood Ranch?
See previous response.

How much water was released out of Lake Manatee?
approximately 15 billion gallons of water was released from the reservoir due to Debby. This is about 2.5 times the total volume of the reservoir. 

How much water is stored at Lake Manatee?
Lake Manatee is 6-billion-gallon reservoir.

Was the release of water from Lake Manatee a one-time emergency event release or multiple?
Controlled releases to maintain manageable lake levels began on Aug. 1, 2024, and continued during the duration of the storm.

Was the release automatically triggered or was it a decision to release?
It was a decision to begin drawdown prior to the arrival of the storm per our standard practice.

Why was the release done?
The release was done to protect the structural integrity of the dam and our drinking water supply; there was not a concern of the dam being overtopped. We are preparing rainfall comparisons between Debby and other major rainfall events.

Are there any repairs or upgrades planned for the dam? How will they address issues seen during Debby?
While the dam performed as expected during Debby, there are ongoing repair/maintenance/resiliency updates that we make on continual basis.

How long will it take to rebuild the plugs?

It will take less than a week to replace the earthen “plug” gates. These earthen gates will only be replaced once the repairs to the center gate at the primary spillway are completed.  Material and equipment are onsite to complete the earthen gate replacement.

When will the center gate become operable?

The work on the center gate is ongoing, with a contractor onsite the week of August 26. Until the contractor is able to identify the underlying cause of the mechanical issue, there is no way to speculate how long repairs may take to complete.

If the center gate was operable during Debby, would it have been necessary to use the secondary spillway?

The operation of the gates was guided by National Weather Service predictions regarding expected rainfall. In anticipation of Tropical Storm Debby, Lake Manatee was lowered to 36 feet. Had the third mechanical gate been operable, it is likely that the secondary spillway would not have been used. It is important to note that staff observed peak flows through the two mechanical gates of about 9,000 cfs (4,500 cfs each gate) and a total flow of about 13,500 cfs between the primary and secondary spillways. Therefore, we would have expected peak flow through the three mechanical gates of about 13,500 cfs.

The actual condition versus a condition with three operational mechanical gates would have been nearly identical with no observable difference water moving through the gates or downstream impacts.

If we have another significant rain event before plugs are rebuilt or center gate becomes operable, what are the options for controlling the flow of water downstream from the reservoir?

The Lake Manatee Dam has 11 gates (3 mechanical and 8 earthen) that maintain lake levels to provide continuous potable water supply throughout the county.  We do operate the lake to provide very limited stormwater retention if it does not conflict with the function of providing potable water supply throughout the county.  During the remainder of the rainy season and while repairs to mechanical center gate are being completed, the County is operating at a lower lake elevation through use of the primary spillway to provide limited stormwater retention.  As we approach the dry season, we will have to increase the elevation of the lake to ensure adequate water supply throughout winter and spring.

Comparison of Debby Rainfall Totals vs. Ian and Irma
Rainfall Charts

Paragraph locked by Anonymous user
Note: BG = billion gallons

Debby total rainfall: 17.95 billion gallons

Ian total rainfall: 12.34 billion gallons

Irma total rainfall: 10.71 billion gallons