New York City Department Of Transportation via Community Board 6.
On Saturday, February 15th and Saturday, February 22d, from 7 am to 1 pm, one lane of the Third Street Bridge over the Gowanus Canal will be closed. Traffic will alternate directions during the closure.
Delays may result, so you may want to avoid the area during those hours.
The closure will allow NYC DOT to remove parts of the bridge that were damaged during Hurricane Sandy so that they may be repaired off site.
Incidentally, the Carroll Street Bridge and the Union Street Bridge were also damaged during the storm in October 2012 and currently can not be swung open to allow boats or barges to pass.