Here are some more news from the Swiss authorities on Lake
Constance and the Rhine.
"You are right: to fix the border at 25 meters of depth
was only discussed."
"Tiefenkarte": You find the contour lines indicating
the depth of lakes on
our maps. But there is no 25-meter-line. For this area
of Switzerland (and
neighboring countries) we use a aequidistance of 10
meters in the maps 1:25000, 20 meters in the maps 0f 1:50 000 and 50 meters in
the maps 1:100 000.
In alpine areas the aequidistance is 20 meters in the
1:25000-maps.
borders on the Rhine: This question is quite complex and
I'm unable to give You precise details. There is a great mix of agreements
between the Lake of Constance and Basel (Basle in older English). In such
questions You are suddenly confronted with centuries of history. For instance:
Till the beginning of the 19th century the Swiss Fricktal - that has a border to
Germany (today Baden-Württemberg) and is situated east of Basel - was part of
Austria. Therefore You still have borderstones in the canton of Basel with the
Austrian escutcheon.
Now back to the Rhine: There are parts of the river east
of Basel, where the border was determined between the Grossherzogtum Baden and
Austria. in other areas it is the ancient Württemberg and the cantons of Aargau,
Zurich or Schaffhausen. Or the German Reich and Switzerland. Sometimes the
border was determined when a power plant was to be built. Or, only on the
bridges a borderline was fixed (to know, who has to pay repair-works), maybe the
border on the water was at a different spot. Or, the "Talweg" (the deepest spot
in the river, that is changing, when gravel is moved by the stream) was
determined as the border.
You see, the question is quite complex and I really
am not the right person to give You a satisfying answer. I just wanted to start
themes. I don't even know who would be the right person. If I had to know more
about, I would start my questioning in the archives of the corresponding cantons
and the German Land of Baden-Württemberg in Stuttgart. In the German part of
Switzerland (and I guess also in Germany) these archives normally have the name
"Staatsarchiv". So You would have to write to the "Staatsarchiv des Kantons
Schaffhausen" in Schaffhausen (Thurgau in Frauenfeld, Zürich in Zurich, Aargau
in Aarau, Basel-Land in Liestal and Basel-Stadt in Basel."
Jesper