Indicates heavy shipping traffic ahead.

Two channels are coming together.  You should pass to the left of this buoy as y ou travel upstream

Marks the right channel limit.  You should pass to the left of this buoy as you travel upstream.

Means the channel crosses a wide stretch of the reservoir from the left bank to the right bank as you travel upstream

Marks the right secondary channel limit.  You should pass to the left of this buoy as you travel upstream.