If Irene hits with sufficient force, a flood of the human waste quaintly known as combined sewer overflow (CSO) is almost a certainty. What is less certain is how much of the heavier, more dangerous contaminants will be churned up by the storm surge and heavy winds and deposited by the flood waters.
The 50-odd blocks that surround the canal — known lately for open-air dance parties and hipster houseboats — are in Zone A and are subject to mandatory evacuation. The two neighborhoods that border the Gowanus, Park Slope and Carroll Gardens, are both uphill from the canal. But whether those hills are steep enough to turn back a toxic shitstorm won’t be known until Irene passes through.