Nonnavigable area on chart

I have an idle curiosity: when looking at a chart of Boston Harbor (#13272) there's a violet-shaded section where some piers are located which says to see note B. Note B says that an act of congress, public law 90-312, declares the shaded area nonnavigable. Finding the actual law, passed in 1968, that's pretty much all it says: "...declared to be not a navigable water of the United States within the meaning of the laws of the United States..." along with a precise description of the boundaries.

What's the effect? There are wharves and piers sticking out almost to the extent of the shaded area, so it's not like there'd be much navigating going on there otherwise, except for boats coming and going (which still has to happen since those piers, from the satellite view, are very much in use). What happens if there's an incident (like a collision) between two boats that are authorized to be there? What rules apply in nonnavigable waters where there are boats nonetheless?

That is interesting.

Obviously it is navigable, as it is full of boats. A little digging indicates that it a legal clause making that area out of the Army Corp of Engineers jurisdiction and responsibility of Section 10 of the rivers and harbor act.

Might be more to it than that. I don't really know. Just a little Google sleuthing on my part.

Yea, I'd guess it was a maneuver back in '68 to get some sort of local control over that section of waterfront. Maybe there was an argument over what could and couldn't be done there, so someone got it declared as outside of federal jurisdiction.

Across from the bar Ted Kennedy frequented

I wonder what's up with this? The brilliance and sagacity of our congress is, of course, well known and respected. Page down to article II:

http://www.nae.usace.army.mil/Porta.../JurisdictionalLimits/US_Navigable_Waters.pdf

In looking at it, that's basically the ENTIRE downtown Boston waterfront. I'll have to ask my friends who are one of the old time nautical families along there to see what they know

From what I found, it was the way to guarantee that development stayed solely in the hands of the City of Boston bs any input from the Army Corps of Engineers or others. What I found is a 2016 document by the Boston Redevelopment Authority....

Thanks all, very interesting!

Notice that the entire area are the Wharf's from Pier 4 all the way to India Wharf. The Act lists Fort Point channel, but non of that is marked in purple. This is all commercial area anyway.