Subject: Re: [BoundaryPoint] world class border arc census was Re: real bjneng try afoot
Date: Jul 16, 2004 @ 05:33
Author: Michael Kaufman (Michael Kaufman <mikekaufman79@...>)
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> Michael,__________________________________
>
> See my insertions below.
>
> Lowell G. McManus
> Leesville, Louisiana, USA
>
>
> ----- Original Message -----
> From: "Michael Kaufman" <mikekaufman79@...>
> To: <BoundaryPoint@yahoogroups.com>
> Sent: Wednesday, July 14, 2004 10:55 PM
> Subject: Re: [BoundaryPoint] world class border arc
> census was Re: real bjneng
> try afoot
>
>
> > Thanks for these maps:
> > For 1. Is the arc the one which faces north with
> the
> > "HUA" of CHIHUAHUA under it and the "S" of TEXAS
> above
> > it? Or the tighter one facing south just to the
> right
> > of it? Or the real wide one facing northeast to
> the
> > right of that?
>
> The arc in this map ( http://tinyurl.com/6msfp ) is
> the really wide curve. The
> others are bends in the natural channel above the
> beginning of the artificial
> channel. There is a short tangent stitch in the
> artificial channel connecting
> the natural channel to the beginning of the wide
> arc. After making the arc, the
> artificial channel enters a very long tangent for
> over five miles. The former
> natural channel is represented on this map by the
> line that wanders away to the
> lower left.
>
> > 2. Arc is the wide curve facing WSW where the
> other
> > stream comes in?
>
> Yes. In this map ( http://tinyurl.com/6u56h ), the
> arc comes at the end of the
> very long tangent mentioned above. The other stream
> coming in is the old
> channel. Notice how it formerly crossed the middle
> of the arc. After the arc,
> there is another short tangent before this segment
> of the relocation ends as the
> river resumes its natural channel.
>
> > 3. Arc faces NNE to the right of "CO" of PRESIDIO
> CO?
> > Or facing S/SSW just below BM 252?
>
> The former. Between arcs 2 and 3, the river has
> occupied its natural channel
> between the cities of Presidio and Ojinaga. Just
> below the highway bridge, it
> enters a tangent artificial channel of approximately
> 1.25 miles without any
> transitional arc. Then, in this map (
> http://tinyurl.com/6qgrl ), that tangent
> ends with a transitional arc back to the natural
> channel just above the railroad
> bridge. The curve near the benchmark is a natural
> bend. There are two more
> tangent artificial channels in the area below the
> railroad bridge, but they are
> without transitional arcs.
>
> > 4. I remember seeing this before - the 1/4 circle
> > facing SE.
>
> Yes. At http://tinyurl.com/5ppgp , you can see the
> natural channel making a
> large meander off to the northwest of this arc. It
> makes another large meander
> to the north of the artificial tangent just below
> the arc. The relocation here
> eliminated both meanders in the river and boundary.
>
> > Also - Is Beaver Island somewhere in this
> vicinity?
> > Is this still an island (if it is in the area, did
> > rechannelization have an effect?)?
>
> The "Beaver Island" tract that was transferred to
> Mexico in the 1970 treaty was
> located near Roma-Los Saenz, Texas (about 48 air
> miles upriver from the fourth
> arc above). It was where the word "Tamaulipas" now
> appears on the map at
> http://tinyurl.com/54zcp . It was a rather squarish
> piece of the USA had been
> been orphaned high-and-dry on the southern side of
> the river by a much earlier
> avulsion. This tract and the more contentious
> Horc�n tract, on which part of
> the town of R�o Rico had unwittingly developed
> (about 26 air miles downriver
> from the fourth arc above) were transferred to
> Mexico in exchange for the two
> meanders gained by the USA at the artificial fourth
> arc. No channel relocations
> were necessary for the transfer of the Beaver Island
> and Horc�n tracts because
> both were already on the southern side of the
> existing river. The island within
> the river that is visible on the map belongs to the
> USA.
>
> > -Mike
> >
> >
> > --- "Lowell G. McManus" <mcmanus71496@...>
> wrote:
> > > The maps from the MXUS Treaty of 1970 showing
> four
> > > arcs are at a scale of
> > > 1:20,000 on three long sheets, each about one
> foot
> > > by three feet. They are
> > > black-and-white aerial photos with the
> boundaries
> > > through both the old channels
> > > (shown by lines between numbered traverse
> points)
> > > and the projected relocated
> > > channels plotted onto them.
> > >
> > > I can scan pertinent portions of these maps for
> you
> > > on request. Meanwhile, here
> > > are links to view the arcs on USGS topo maps
> showing
> > > the arcs in the relocated
> > > channels.
> > >
> > > There are three arcs in the Presidio/Ojinaga
> area:
> > > Curve No. 1: http://tinyurl.com/6msfp
> > > Curve No. 2: http://tinyurl.com/6u56h
> > > Curve No. 3: http://tinyurl.com/6qgrl
> > >
> > > The fourth is above Hidalgo/Reynosa:
> > > http://tinyurl.com/5ppgp
>
> > >
> > > Lowell G. McManus
> > > Leesville, Louisiana, USA
>