FIU Study Has Recommendations for Updating Building Codes

The university’s Sea Level Solutions Center in the Institute of Water and Environment received a grant from the Florida Building Code Commission to look at groundwater levels and consider sea level in building planning.

by Jim McKay / November 15, 2019

A study by Florida International University on the flooding risks in Florida could help that state update its buildings codes to reflect sea level rise and climate change in the future, something the codes don’t account for now.

The university’s Sea Level Solutions Center in the Institute of Water and Environment was awarded a grant from the Florida Building Commission to evaluate groundwater level, taking sea level rise into account, and changes in extreme rainfall in Miami-Dade County to measure potential implications for the building codes.

The study looked at potential flood levels, rain loads on buildings, and rising water tables that affect infrastructure. The science of predicting future rainfall and sea level rise is tricky and not as accurate as predicting temperature rise, but the study offered new data and some suggestions, including increasing flood elevation for buildings by one to two feet.

“We recommend some potential changes that should be incorporated into future planning,” said Jayantha Obeysekera, director of the Sea Level Solutions Center and associate director of the Institute of Water and Environment. “Go through the building codes and identify on this new research where the code itself should be modified.”

Elevating is taking place in other places, but Obeysekera said whether to elevate is not the question but how much elevation is needed, as Florida is unique in this regard. “A lot of other places they are elevating because the storm surge will be higher, but in Florida, flooding could be affected by the water table and increased rainfall, so there are no standards.”

Obeysekera explained that in Florida, sea level rise in South Florida will cause saltwater to push fresh water inland and up, inundating some parts of the coastal areas because the water table is only three to five feet below the surface. Also, saltwater creeping up can ruin the foundations of infrastructure.

“We get the ‘sunny day’ flooding where you don’t have to have any rainfall; just the groundwater tables coming up can cause flooding,” said Michael Sukop, Florida Climate Institute executive board member and part of the study team. “This particular model we used covers the entire county and captures long-term effects of sea level rise over a 50-year period.

Obeysekera and his team ran groundwater computer models incorporating higher sea level and future rainfall and produced maps that local governments and the Building Commission can use for future building permits and infrastructure systems.

In some areas of Florida, like Miami, elevating buildings may be problematic, and the study recommended retrofitting buildings as a possible remedy. “Retrofitting the building may be leaving the first floor open or for parking so you don’t have to worry about it being flooded,” Obeysekera said.

Other possibilities including raising the crown elevation on roads, using saltwater-resistant materials when retrofitting or constructing buildings and elevating appliances and electrical utilities.

The solutions obviously aren’t without costs. Elevating a 2,000-square-foot home could cost anywhere between $900 and $5,000 per foot, according to a report in the Miami Herald. “For an additional one foot, that’s a considerable increase,” Truly Burton, government affairs director for the Builders Association of South Florida, told the Herald. “We just did it 18 months ago.”


 

Platforms & Programs