Measures target flooding
Drainage rules affect Broward developers
Broward County is taking steps to keep climate change from turning future summer rainstorms into major flooding events.
While much attention has focused on how rising sea levels threaten barrier islands and coastal communities, climate change will also raise groundwater levels further inland, leaving less ground to absorb South Florida’s heavy downpours.
The county is requiring new building projects to be able to drain larger amounts of water to prevent the flash floods.
“We are aware that rising seas require changes in our planning and design standards, to ensure that our communities remain safe and livable,” Commissioner Beam Furr said.
The drainage requirements are tied to new groundwater level maps that are modeled on a projected 2-foot sea level rise by 2060.
Jennifer Jurado, Broward’s chief resilience officer, said the new regulations keep the county at the forefront of efforts to address climatechange. The new rules rely on maps that predict future conditions, instead of past practices of basing regulations on current or historical data, she said.
Palm Beach County officials said they have not undertaken any large remapping efforts related to climate change.
Broward’s requirements, which take effect July 1, won’t force developers to do things differently but would require drainage systems to be able to handle greater amounts of
storm water and not flood nearby properties. That could mean more French drains — a gravel-trench with a perforated pipe that carries water away from a structure — additional drainage wells or larger water retention areas on site, Jurado said.
The analysis the county has done indicates the new rules could raise total construction costs by no more than 1.5 percent, she said.
"This isn’t going to cease development," Jurado said.
Broward commissioners approved the new average wet season groundwater level maps Tuesday. Thewet season is when ground water is at its highest level. Existing maps are already outdated in terms of how high the groundwater level is, Jurado said.
The new rules won’t have a significant impact in western Broward communities, where the groundwater level rise is not predicted to be as great, or in areas where high ridges still leave plenty of space between the surface and groundwater. The most affected communities will be in southeast Broward, around cities like Fort Lauderdale and Hollywood, where groundwater is closer to the surface, Jurado said.
Commissioners have also agreed to update the county’s 100-year flood elevation maps to take into account expected sea level rise. Those maps are used to establish base elevations for new buildings and other structures.
The new maps are expected to showmore potential flooding areas than federal emergency management flood maps, which would require developers to do more to protect against flooding.