[Talk-us] [Talk-us-newyork] LAST CALL: Looking to start on reconciling New York City admin boundaries

[Kevin Kenny]

On Sat, May 21, 2022 at 5:46 PM Marcel Dejean <mrd79 at case.edu> wrote:

> Are you sure that the boundaries follow "the east shore of the East River
> as it stood in 1898"? The New York City Administrative Code says
>
> The borough of Manhattan shall consist of the territory known as New York
>> county which shall contain all that part of the city and state, including
>> that portion of land commonly known as Marble Hill and included within the
>> county of New York and borough of Manhattan for all purposes pursuant to
>> chapter nine hundred thirty-nine of the laws of nineteen hundred
>> eighty-four and further including the islands called Manhattan Island,
>> Governor's Island, Bedloe's Island, Ellis Island, Franklin D. Roosevelt
>> Island, Randall's Island and Oyster Island, bounded by the following
>> described line: Beginning at the northerly United States bulkhead line of
>> the Harlem river at the junction of the Hudson and Harlem rivers; thence
>> along the northerly and easterly *United States bulkhead lines of the
>> Harlem river* to the l*ow-water mark on the westerly bank of the Spuyten
>> Duyvil creek as it existed prior to its being filled in*; thence along
>> said low-water mark of Spuyten Duyvil creek to the easterly United States
>> bulkhead line of the Harlem river; thence southerly along the *easterly
>> United States bulkhead line of the Harlem river* to a point where said
>> United States bulkhead line of the Harlem river intersects the northerly
>> United States bulkhead line of the Bronx kills; thence along the*
>> northerly line of the United States bulkhead line of the Bronx kills* to
>> the intersection of the northerly United States bulkhead line of the East
>> river; thence *across the East river* to the low-water mark on the shore
>> of Long Island, so as to include Randall's Island and Ward's Island; thence *along
>> the low-water mark on the shore of Long Island* to the southerly side of
>> Red Hook; thence across the Upper bay to the westerly boundary of the
>> state; thence northerly along such westerly boundary of the state to a
>> point where a perpendicular drawn from the point or place of beginning
>> intersects such westerly boundary of the state; thence easterly along such
>> perpendicular to the point or place of beginning; including all the islands
>> or parts thereof situated within the aforedescribed bounds.
>>
>
> Which seems to imply that the Queens/Brooklyn boundaries move as the shore
> is filled in to wherever the low water mark is, and the Bronx boundaries
> change when the bulkhead line is redefined. The Brooklyn piers are, of
> course, in Manhattan. Sometimes it's not obvious what's a pier and what
> isn't so I just worked with what was already mapped.
>

As I explained in another channel, I was aware of this, and I'm reasonably
certain that there are many events that would alter the shoreline without
altering the boundary. Riparian law is complex, and whether a boundary or
property line moves depends on the process by which the water advanced or
receded.  The law abounds with terms like 'erosion', 'accretion',
'reliction', and 'avulsion', all of which have specialized meanings in
context. In a great many cases, a description like this will be interpreted
according to how the shoreline stood at the time the boundary was agreed
upon. The description does _not_ in general imply that construction at the
shoreline will alter the boundary, any more than a river's changing course
would alter the land ownership on its banks.

Supporting this claim, all the city, State and Federal sources (NYC GIS,
NYS GIS, TIGER 2021) show a jog in the city line  near 40.8898 N, 73.8231 W
where a tiny strip of Westchester County penetrates on shore, following a
former shoreline.  The dredging of the HUtchinson River and filling of the
east bank did not affect the boundary, which was described as following the
river.  Before a day or two ago, OSM did not have this feature, because a
mapper had corrected the "obvious" failure to follow the river and then
conflated the Borough of the Bronx with the shoreline.
https://kbk.is-a-geek.net/attachments/20220522/mount-vernon-corner.png
shows the area in question on OSM.  THe heavy black line shows the admin
boundaries from state and city GIS systems (which agree).  The dashed red
line is the 2021 version of TIGER/Line.  The somewhat drunken wiggling of
the boundary is fairly common in TIGER/Line files; somehow, the process
that produces them introduces a tremendous amount of noise in boundaries.
In virtually all cases, where the two differ and I have a third source for
verification, or have a boundary visible on orthoimagery, the NYSGIS data
follow physical and cultural features associated with boundaries (fence and
field lines, courses of stable streams, and so on) while TIGER files run
astray.

I would probably have to travel to NYC to verify the history of the law in
question, although I might be able to find the materials at University of
Albany. I strongly suspect that the language "as it existed prior to its
being filled in" was added in 1914, and that all the rest of the
description dates from the Great Consolidation that established the City of
Greater New York.  (I've been told that at some point prior to 1898, the
Cities of New York and Brooklyn engaged in protracted litigation over where
the boundary lay in the Brooklyn Navy Yard, since it affected the
compensation that each received from the Federal government for the taking
of land.)

In any case, the OSM definition of 'coastline' refers to mean spring-tide
high water, while the legal definition shown here refers to the 'low water
mark'.  I'd have to do more research to interpret whether the 'low water
mark' refers to the mean daily range of tide, to the spring-tide low water,
or to some sort of extremum - the lowest point to whcih the water has ever
receded.  It's indisputable, though, that the border between the boroughs
will differ by at least the range between daily low water and monthly high
water, so the legal definition of the boundary and OSM's definition of the
coastline differ by at least that much tidal range. You can see this in a
high-tide image at
https://kbk.is-a-geek.net/attachments/20220522/hell-gate.png - the line
clings to the bulkheaded shoreline (ducking inland of a wharf built after
the line was laid down) but follows the low water mark along the tidal
shoreline.  The OSM coastline tracks the high tide line fairly accurately
in here., and the line labeled 'Queens' (referring to the borough rather
than the county) is glued to the coastline.

Moreover, OSM shows the Borough of Manhattan ending a little bit offshore
from the west banks of the East and Harlem Rivers, while the Boroughs of
the Bronx, Queens and Brooklyn follow the east banks. In all cases the
boroughs are coterminous with the counties, and the line of New York County
is over on the east side of the rivers.  I don't see a strong reason not to
conflate the two, nor to extend the borough lines along the coastline where
the East River joins the Long Island Sound or along New York Harbor, the
outer New York Bay, or the back bays of Long Island and Staten Island.  All
the maritime boundaries extend to the three-mile limit.  The current OSM
definition of the Borough of Queens, for instance, fails to encompass the
community of Broad Channel in Jamaica Bay. (The OSM line for Queens County
does include this island.)

-- 
73 de ke9tv/2, Kevin
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