Fixes for Sunset Harbour to Prevent Flooding

Last year, during a heavy rain event, the City reported parts of the new stormwater system in Sunset Harbour were not working to their intended capacity, causing flooding in low lying areas. Following a “comprehensive evaluation” on the system’s capacity as constructed, Miami Beach City Manager Jimmy Morales wrote in a memo to Commissioners this past week that it is capable of handling the 5-year design storm, “however, some low lying properties, especially the properties below sea level will experience standing water for a short amount of time during rainfall events with intensities equal to or greater than 1.8 inches per hour.”
 
“As a result of this condition, the City and Lanzo [Construction, the contractor] reached an agreement” on improvements, Morales wrote. They include: installation of 16 backflow prevention devices, rerouting of roof drains at the southeast corner of 20^th Street and Purdy Avenue, and installation of three micro pump stations in the right of way.
 
In a letter to the City outlining the agreement, Lanzo COO Fred Tingberg and Holly Kremers for Engineer of Record Wade Trim wrote “The performance improvements identified above should provide a 5-year level of service within the ROW [right of way] and no water in the first floor of buildings for the 5-year, 24-hour SCS Type III design storm with 6-inches of total rainfall during a tidal outlet condition of 2.7 ft. at the outfalls.”
 
They also noted, “[I]t is recommended that property owners conduct additional improvements to address private drainage needs where the properites are lower than sea level.”
 
The total cost of the improvements in the amount not to exceed $475,000 was presented as a change order which was approved at the Commission meeting this week. Two thirds of the cost will be covered by Lanzo/Wade Trim and one third or $158,350 will be covered by the City.  
 
Sunset Harbour was the City's first resiliency project to combat flooding from sea level rise.
 
 
 Photo: City of Miami Beach