It's a bit hard to make out what's going on in the picture, but that's because it was hard to make out in reality, too. It's a picture of one of the countless canals cutting across Bangkok, but this one has a big hole in it. Specifically, steel walls were erected in a box and then pumped dry, presumably to work on the riverbed (canalbed?) beneath. This created a big traffic jam for the water taxis, which normally run at extreme speeds through the narrow canals.