As we enter hurricane season, it’s helpful for residents to understand how Grandezza’s stormwater system is designed to protect our homes and manage heavy rainfall.
HOW THE SYSTEM WORKS
Grandezza’s stormwater system was designed more than 20 years ago in accordance with strict civil engineering and regulatory standards. Its primary purpose is to safely collect, store, and gradually discharge stormwater during heavy rain events.
• Our 24 lakes are the backbone of the system. They collect and store rainwater throughout the community.
• Most lakes are interconnected. 22 of the 24 lakes are linked by large underground pipes, which also connect to street drains. This ensures that water levels remain equal across the system.
• Street drains reflect lake levels. When you see water in a street drain, it is not a blockage. It simply means the lakes have reached that same level.
• Streets provide temporary storage. During significant storms, when the lakes reach capacity, water is intentionally stored on roadways until it can safely drain.
CONTROLLED WATER RELEASE
Grandezza has three regulated outfalls—two along the Ben Hill Griffin berm and one near the Corkscrew Road maintenance exit. These structures release water at a controlled rate approved by the South Florida Water Management District.
This controlled discharge is critical. It ensures that surrounding roads and neighboring communities are not overwhelmed during major storm events.
KEY DESIGN ELEVATIONS
The system is carefully engineered using specific elevation benchmarks:
• Lake control level: 17.0 feet above sea level
• Road elevation (minimum): 19.0 feet
• Perimeter berm elevation (minimum): 19.2 feet (constructed higher in practice)
• Home finished floor elevation (minimum): 20.5 feet
Once lake levels exceed 17 feet, water begins flowing out through the controlled outfalls.
WHY FLOODING CAN OCCUR (AND WHY THAT’S OK)
The system is designed to meet the standard for a “100-year storm” which is defined as approximately 13.5 inches of rain over a three-day period. Under these conditions:
• Temporary street flooding is expected
• Water may take up to 12 days to fully recede
This is not a failure. It is exactly how the system is designed to function to protect homes.
POST-HURRICANE IRMA IMPROVEMENT
Following Hurricane Irma, Grandezza added an important enhancement:
• A 12-foot-wide emergency spillway was constructed along Corkscrew Road
• Elevation: 19.2 feet above sea level
• Purpose: To accelerate drainage during extreme events when water levels exceed berm height
While this spillway helps reduce drainage time, it does not eliminate temporary street flooding during severe storms.
NOTE REGARDING SAVONA
The Savona neighborhood follows the same stormwater design principles described above, with one key difference—its overall elevation is approximately one foot higher than the rest of Grandezza. As a result, Savona’s road elevations, home finished floor elevations, perimeter berm height, and lake control levels are all correspondingly higher. Savona also includes an overflow feature functionally equivalent to the community spillway, which provides additional capacity to discharge excess water during extreme storm events. While the elevations differ slightly, the system operates in the same manner and provides the same level of protection.
KEY TAKEAWAYS FOR RESIDENTS
• The lakes are designed to store stormwater
• Water levels are equal throughout the system
• Streets are intended to serve as temporary overflow storage
• Water in drains means the system is working—not clogged
• Outflow is intentionally restricted to prevent regional flooding
• The spillway helps drain water faster, but flooding during major storms is still expected
CONCLUSION
Grandezza’s stormwater infrastructure has performed as designed through multiple major storm events. While residents may observe temporary street flooding during heavy rains or hurricanes, the system’s primary goal of protecting homes from flooding has been successfully achieved.
STORMWATER SYSTEM – AT A GLANCE
Grandezza’s lakes are designed to store stormwater, with lakes interconnected and maintained at the same level. During heavy rain, streets temporarily hold excess water once lakes reach capacity and this is by design. Water drains out at a controlled rate to protect surrounding areas. Homes are built above road level for protection. Savona follows the same design, with elevations approximately one foot higher.
STORMWATER FACTS
• Lakes store stormwater
• Lakes are interconnected
• Street flooding is temporary and expected
• Water levels in streets = lake levels (not clogged drains)
• Outflow is controlled to prevent regional flooding
• Homes are built above road level
• Savona operates the same system at slightly higher elevations
