OIL-SPILL/The oil is no longer gushing into the Gulf of Mexico from the broken BP well, and a final “bottom kill” is in prospect — though delayed by an iffy weather forecast. That means the environment’s on the mend along the Gulf Coast, right?

Not really. There’s the little problem of subsidence to deal with.

Because the Mississippi River has been channeled to control flooding, coastal wetlands have been starved of sediment. Without fresh sediment coming down the river, wetlands can’t keep up with erosion and protective marshes can turn into open water. Subsidence is what this phenomenon is called.

This sinking is already occurring near Venice, where marinas cluster around the toe of Louisiana’s boot shape. Take a look at a road that looks like a stream in a video clip I took in mid-July:

The rhythmic clicking sound is the hazard blinker on the car.

Photo credit:  REUTERS/Sean Gardner (Oiled crane on a tree limb on a small island in Bay Barataria near Grand Isle, Louisiana June 12, 2010)