It has been going on for a couple months, and seems to get worse after heavy rain.The area around the road to the National Park dock (close to Red Hook), is somewhat of a wetland environment. So, how about a possible alternate source for the smell: decay of organic material in a water logged environment due to increased rainfall in recent months?
"Why do swamps sometimes smell like rotten eggs?...all wetlands are oxygen-deprived environments where microscopic anaerobic bacteria break down organic matter and—in the process—produce hydrogen sulfide: the source of the stink."
"Anaerobic decomposition takes place in nature, as in the decomposition of the organic muds at the bottom of marshes and in buried organic materials to which oxygen does not have access. Intensive reduction of organic matter by putrefaction is usually accompanied by disagreeable odors of hydrogen sulfide and reduced organic compounds which contain sulfur, such as mercaptans (any sulfur-containing organic compound)."