It's a chilly February day as we set out from the Arkansas side of the Mississippi River. We're in a 24-foot cypress canoe, paddling south, with John Ruskey guiding in the stern.
The first stretch of journey, just south of Helena, Ark., is far from wild. We paddle past lots of industry lining the riverbanks: Along the shore, we see grain being pumped from a giant grain elevator into barges on the river. We pass coal and petrochemical docks, too, supplying or offloading the barges that ply this river up to Minnesota, and down to the Gulf of Mexico.