What do you consider the definition of thalweg and thread to be??ÿ My coworker is sitting for a state exam on Monday and brought this to my attention.?ÿ I always thought that Brown's definition to be correct, not the 2009 BLM Manual and that the thalweg was the deepest part of the channel.?ÿ I don't have a personal copy of Black's so I can't see if it has definition.?ÿ?ÿ
They always ask that question. Thalweg is the deepest part of the channel. Thread is the center of the stream. Your state laws may differ.
To most people. they would seem to be identical. Anything that requires 200 words to explain is BS.
Neither exists in nature. They are concepts.
I agree. What is the point in learning these archaic words in order to become a land surveyor? Thalweg is not even an English word.
It is just brabble that some cockalorum thought up to fuzzle the uninitiated future Land Surveyors.
welcome to the chicanery that is the FS and PS today....
Those two sources give three definitions, and the names for the deepest part are contradictory.
-Deepest part
-Line of navigation
-center of stream
There is also midway between the banks.
The very name translated from German thalweg to "valley way" says the Manual has it backward. Black's, Brown, Mirriam-Webster, and Wikipedia agree thalweg is deepest line.
There was a relevant forum thread a few years ago with some case history.
https://staging.rpls.com/community/surveying-geomatics/thread-of-river/
I think y'all is all wet. Or the stream is dry.
N
Thalweg comes from navigation law. Thread comes from boundary law. And then they mixed them. Political v. private boundaries, equitable considerations considered by the courts, etc.. My best advice is to answer according to the manual if question is on FS or PS. Answer the other way if question is on State exam. Especially on the water law questions, and especially in a colonial State, you need to answer differently depending on which exam.
That is what makes this a terrible question to be put on any exam.
Test questions for professional practice licensure should be focused on actual practice concerns, not text book definitions.
@duane-frymire Your post explains itself. Having the line which controls commerce as a political boundary is perfect. Is places States on equal footing..
@duane-frymire Your post explains itself. Having the line which controls commerce as a political boundary is perfect. Is places States on equal footing..
Agreed. It seems to me that unless you are talking about political divisions then the manual's definition of thalweg is mute. If a waterway is navigable then the channel is owned by the state and if it is not navigable then the geomorphologic definition of thalweg, which is basically the same as the manual's definition of thread, controls. Generally speaking, the deepest part of a waterway is not the center of the channel.
Wow, my degree in geomorphology finally paid off.
Many of our river bottoms/creek bottoms are weathered/eroded limestone. All sorts of minor pooling opportunities. There isn't a single little trickle of water that would continuously be found so as to define a thread/thalweg. The actual bank lines are far from being smooth continuous lines. Attempting to define a pair of lines for which a midpoint between them could be calculated would require something like scanning as opposed to common field measurements. That would be an expense that would be far too great to justify its use simply to be MORE precise.
@john-putnam And unlike in PLSS, some colonial States Nav in fact does not equal Nav in law, can be Nav in fact and still private bed.
Iowa in the PLSS has this distinction. Only a few larger streams are owned by the state by being declared navigable in the original surveys, but any stream that you can get a kayak down for some months of the year can be used by the public.
https://govt.westlaw.com/iaag/Document/Iff56be80f59811da90bd8aaf6ec74e0e
For some reason surveyors have begun to use rhe term "thalweg" to mean "thread". The use of the term "thalweg" makes no sense in reference ro a water course not navigable in fact.
It is common for a surevor to need to locate a "thread", but most will go their while career without locating a "thalweg". Nonetheless, not knowing the difference could lead to a disastrous miscalculation.
@bill93 That's interesting, I thought most if not all PLSS had gone the other way and said failure to meander didn't matter. Although the result is basically the same from a practical standpoint.
In Missouri, the public craps on private land along streams of all sizes freely. In Kansas, very few are foolish enough to try.
As it turns out, surveyors have to share words with everyone else, and we don't get to redefine things just because they enter our sphere of influence.
Thalweg has a clear meaning in hydrology and geology, and many surveyors need to know what a thalweg is to conduct engineering surveys, even if they are not using the "thalweg" for boundary surveying.
BLM (bless their hearts) seems to have redefined thalweg in the Manual (out of thin air), much like they redefined "straight line" to mean the opposite.
I get that sometimes words take on shades of meaning depending on application, but they shouldn't be completely redefined...
