Devices to Measure the Speed of Flowing Water?

Riverman:

Where are you these days? It was a busy summer, so I lost track. Last that I
recall, you had bailed out of the Congo and were in Wales going back to school.
It is always possible that I imagined that though. Hopefully you are still
out of harms way.

Facing the double nickels (55) next week. It is clear now that my life span
will not hold all of my dreams and goals. Pity that. So one must prioritize,
and that puts WorkerBee-ism pretty low on the list. Still, I show up every
day, but the motivation not to is much increased. Fact is we life way too
short a period of time.

So question for the group:

If you had one last trip what would it be? The reasons for last don't matter -
it could be anything from dying to being locked up in jail for violating the
Patriot Act, or selling ImClone stock.

Anarctica would be my choice, though not much paddling possible there.
The Nahanni or Yukon if I could convince my wife we wouldn't get eaten by
Bears.

Blakely
Blakely LaCroix
Minneapolis, Minnesota, USA.
RBP Clique member # 86.

The best adventure is yet to come.
 >> Stay informed about: Devices to Measure the Speed of Flowing Water? 

"Scott M. Knowles" wrote...
 >
 > That's cool and you're right, I haven't looked at them in a few years.
 > Questions. Even with SA off, what's the position error? I
 > understood it's at best 3 meters, often 4-6+ meters, and worse with
 > fewer satellites. If that's the case I don't see if measuring flow
 > over short intervals accurately. Or I'm missing something.

A good discussion is at <a rel="nofollow" style='text-decoration: none;' href="http://www.cast.uark.edu/cast/bruce_gps/GPS_Week4.ppt." target="_blank">http://www.cast.uark.edu/cast/bruce_gps/GPS_Week4.ppt.</a>

Errors vary with time, and vertical position error is somewhat greater than
horizontal position error. RMS horizontal position error is on the order of
2-2.5 meters. The author of the presentation describes the RMS error as a 95%
probability, based on a 95% confidence interval, that the position will be
within the stated distance. At <a rel="nofollow" style='text-decoration: none;' href="http://members.shaw.ca/pdops/WAAS.html" target="_blank">http://members.shaw.ca/pdops/WAAS.html</a> you can
see a sample of a WAAS-enabled GPS that shows horizontal position errors from
benchmarks ranging from 0.0 to 2.2 meters.


 > How often do you check your position and average velocity? Are these
 > in basic models GPS's or more advanced ones?

If the GPS has a map (either a built-in "base map" or higher-resolution area map
loaded from CD), position is constantly displayed. You can monitor lat/long as
well, and see whether it's wandering while you're stationary. Even basic
handheld GPS units can display average speed (since the last time the log was
reset) as well as current speed.


 > It would be interesting to check it in realtime for continues velocity
 > computations. It would give you the average over the line you go,
 > which means maintaining a line along the direction of the flow so the
 > value isn't representing a wandering line or with any paddling
 > included. And it won't give you the average at a point but along that
 > line (reach). I'm not sure I'd want to check in fast(er) flows.

I've brought my GPS on my kayak many times. Velocities are very consistent when
paddling a relatively straight course, and changes can be seen quite easily.
When accelerating and/or turning, the update rate of the unit (mine has 2
selectable rates; the higher rate uses batteries much faster) makes a big
difference. I see good, consistent results with the high update rate (5/sec).
 >> Stay informed about: Devices to Measure the Speed of Flowing Water? 

John R Weiss wrote:

 > I've brought my GPS on my kayak many times. Velocities are very consistent when
 > paddling a relatively straight course, and changes can be seen quite easily.
 > When accelerating and/or turning, the update rate of the unit (mine has 2
 > selectable rates; the higher rate uses batteries much faster) makes a big
 > difference. I see good, consistent results with the high update rate (5/sec).

Yes, I use mine when kayaking as well and the velocity readings appear
very reasonable and consistent. But I'm wondering what make/model you
have that updates 5 times a second. The ones I've seen that have
faster than once/second updates have also had very high price tags
and weren't really designed for activities like kayaking.
 >> Stay informed about: Devices to Measure the Speed of Flowing Water? 

"Peter" wrote...
 >
 > But I'm wondering what make/model you
 > have that updates 5 times a second. The ones I've seen that have
 > faster than once/second updates have also had very high price tags
 > and weren't really designed for activities like kayaking.

Garmin GPS 3+. "Battery saver" mode is 1/sec update; turn that off for 5/sec.

Waterproof. Has been rained on and sprayed with salt water many times. Still
works.
 >> Stay informed about: Devices to Measure the Speed of Flowing Water? 

John R Weiss wrote:


 >
  >> But I'm wondering what make/model you
  >>have that updates 5 times a second. The ones I've seen that have
  >>faster than once/second updates have also had very high price tags
  >>and weren't really designed for activities like kayaking.
 >
 >
 > Garmin GPS 3+. "Battery saver" mode is 1/sec update; turn that off for 5/sec.

Better check that. All Garmins that I've seen, including my III+, only
update once per second in "Normal" mode. "Battery Saver" mode reduces
that to once every 5 seconds provided your previous movement was fairly
predictable.
 >
 > Waterproof. Has been rained on and sprayed with salt water many times. Still
 > works.

The unit itself is rated to IPX7 for waterproofness, which corresponds
to immersion in still water at a depth of 1 m for 30 seconds. However
Garmin does not certify that the battery compartment is waterproof and
saltwater in there could quickly corrode the contacts, so it's generally
still best to protect the unit in a clear waterproof pouch.
 >> Stay informed about: Devices to Measure the Speed of Flowing Water? 

"John R Weiss" (jrweiss98155@.comNOSPAMcast.net) writes:

  >>
  >> I've paddled lots of rivers that flow at somewhat
  >> less than 4mph - so slow that GPS is definitely unreliable for speed
  >> measures.
 >
 > If it's that slow, its speed is probably irrelevant anyhow...

everthing is that slow when paddling. if you are paddling against a 4 mph
current you are not making much progress which would be one good reason to
want to measure the rate of flow.

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 >> Stay informed about: Devices to Measure the Speed of Flowing Water? 

Montreal to the mouth of the Columbia, a canoe trip and tribute to David
Thompson, mapmaker. It would cover just about every kind of water, and
the best of most kinds.
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 >> Stay informed about: Devices to Measure the Speed of Flowing Water? 

in article cjd9h8$me$1@freenet9.carleton.ca, William R. Watt at
ag384.RemoveThis@FreeNet.Carleton.CA wrote on 9/28/04 11:18 PM:

 >
 > Montreal to the mouth of the Columbia, a canoe trip and tribute to David
 > Thompson, mapmaker. It would cover just about every kind of water, and
 > the best of most kinds.

That sounds good.

I'll go for a circumnavigation of Newfoundland.
 >> Stay informed about: Devices to Measure the Speed of Flowing Water? 

"William R. Watt" wrote...
 >
   >>> I've paddled lots of rivers that flow at somewhat
   >>> less than 4mph - so slow that GPS is definitely unreliable for speed
   >>> measures.
  >>
  >> If it's that slow, its speed is probably irrelevant anyhow...
 >
 > everthing is that slow when paddling. if you are paddling against a 4 mph
 > current you are not making much progress which would be one good reason to
 > want to measure the rate of flow.

I get consistent velocity readouts on my GPS down to well under 1 knot. If it's
reading 0, it's likely moving at less than 1/4 knot.
 >> Stay informed about: Devices to Measure the Speed of Flowing Water? 

"Peter" wrote...
 >
 > Better check that. All Garmins that I've seen, including my III+, only
 > update once per second in "Normal" mode. "Battery Saver" mode reduces
 > that to once every 5 seconds provided your previous movement was fairly
 > predictable.

OK. I'll check the book again. It's been 3 or 4 years since I read it.

 > Garmin does not certify that the battery compartment is waterproof and
 > saltwater in there could quickly corrode the contacts, so it's generally
 > still best to protect the unit in a clear waterproof pouch.

I do when kayaking, but not generally when on the sailboat.
 >> Stay informed about: Devices to Measure the Speed of Flowing Water? 

railtramp.TakeThisOut@aol.com (Blakely LaCroix) typed:

 > [snip Myron stuff]
 >
 > So question for the group:
 >
 > If you had one last trip what would it be? The reasons for last don't
 > matter - it could be anything from dying to being locked up in jail for
 > violating the Patriot Act, or selling ImClone stock.

Well, first off, it couldn't possibly be for selling ImClone stock.
Nor for any other kind of market manipulation or tax evasion -- but
that's just my middle-class values talkin'.

OK, assuming good health and physical fitness, and no particular time
constraints, I'd go Washington to Washington; ocean to ocean.

I'd get a long, lightweight Bell or Winona canoe, a set of portage
wheels, and a folding bicycle, and rig a hitch to trail the wheeled
canoe behind the bike. I'd replace my two-man tent with a one-man
backpacker's tent, but also devise a stakeless lean-to system using
the boat and paddles (for awkward non-campsites). I'd replace my down
sleeping bags with a Hollofil bag. I've got a couple of big drybags
with packstraps and hipbelts, in which I'd pack my clothing and food,
and I'd buy at least two new Whisperlite stoves and at least two
backup Thermarests. I've got a ****load of polypro and down clothing,
and lotsa good summer wetware from that flyfishing-gear company, but
I'd probably want to start the trip with a brand new Goretex drysuit.

I'd leave Fletcher's Boat House on the tidal Potomac inside
Washington, DC city limits and paddle* up the Potomac to the North
Branch of the Potomac River, up the NB Potomac to the Savage River, up
the Savage and the Savage Reservoir to where there is a five- to
seven-mile portage (pulling the boat on the portage wheels along a
two-lane asphault road) across the Eastern Continental Divide to the
South Fork of the Casselman River.

I'd paddle* down the Casselman to the Youghiogheny, down the Yough to
the Monongahela, down the Monongahela to the Ohio, and down the Ohio
to the Mississippi.

I'd paddle* up the Mississippi to the Missouri, up the Missouri to the
Madison, and up the Madison to Hebgen Lake, where it is about a ten
mile portage (by road) across the Continental Divide to Henry's Lake.
(I'd expect to use the bicycle/wheeled-boat system to get around some
of the dams and/or dewatered stretches of the Missouri).

I'd paddle* down the Henry's Fork to the Snake River, Down the Snake
to the Columbia, and Down the Columbia to Astoria, OR on the Columbia
estuary, being sure to spend at least one night on the WA side in the
estuary.

Ideally I'd leave DC on January 1 of a mild winter and not be frozen
off the water before I hit the Mississippi in mid-spring. Getting up
the Mississippi at spring flood would be tough. Getting up the
Madison in late summer might be impossible. But I'd want to get
through Hell's Canyon and out of Idaho before the second Winter sets
in. A secondary goal would be to finish within one calendar year, but
if I had to weather over somewhere (er, ah... actually I'd let the
gear weather over while I flew to Tucson or San Diego!) I'd still call
it a success.


* and portage where necessary.


-Richard, His Kanubic Travesty
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rhopley[at]earthlink[dot]net
Nothing really matters except Boats, Sex, and Rock'n'Roll
rhopley[at]wfubmc[dot]edu
OK, OK; computer programming for scientific research also matters
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 >> Stay informed about: Devices to Measure the Speed of Flowing Water? 

"Blakely LaCroix" wrote in message

 > Riverman:
 >
 > Where are you these days? It was a busy summer, so I lost track. Last
 > that I
 > recall, you had bailed out of the Congo and were in Wales going back to
 > school.
 > It is always possible that I imagined that though. Hopefully you are
 > still
 > out of harms way.
 >
 > Facing the double nickels (55) next week. It is clear now that my life
 > span
 > will not hold all of my dreams and goals. Pity that. So one must
 > prioritize,
 > and that puts WorkerBee-ism pretty low on the list. Still, I show up
 > every
 > day, but the motivation not to is much increased. Fact is we life way too
 > short a period of time.
 >
 > So question for the group:
 >
 > If you had one last trip what would it be? The reasons for last don't
 > matter -
 > it could be anything from dying to being locked up in jail for violating
 > the
 > Patriot Act, or selling ImClone stock.
 >
 > Anarctica would be my choice, though not much paddling possible there.
 > The Nahanni or Yukon if I could convince my wife we wouldn't get eaten by
 > Bears.
 >
 >
Hey rt:
No, you didn't imagine it. When the guns started going off in the spring, we
cancelled Final Exams and got the next plane out (disrupting my plans to go
to the interior for a week, including a 3-day canoe trip). I went to Wales,
met up with some Usenet friends and spent a week flyfishing, then a month in
Grad school in Cornwall. Then back to the US for a few weeks to tend to the
house, back to Sweden for a few weeks for some more wilderness exploring and
flyfishing, and now I'm back in Congo for one last year. Things here are
stable and quiet, but no one is fooled and the expectation is that if we get
out in the spring without any suprises, we'll be lucky.

Just passed the 46 milemarker myself, and the feeling that there's just too
many plans and too few days left is creeping up on me, too. Every ounce of
my being wanted to take a year off this year and get back into the old
lifestyle: buy a solid van and a new canoe, spend the daylight months in
Canada on the rivers, and then the winter months skiing and doing some
Mexican trips. But SWMBO was very adamant that if I left her in Congo (she
was not in a position to take a year off), she could not guarantee that we'd
still be together at the end of the year; so I got convinced to come back
for another year. It was *so* against all my old, reliable instincts, as I
feel like I just put another nail in the coffin and missed the last best
opportunity to get about 15 years younger and 20 pounds lighter... I also
wonder if life is going to be long enough for my own plans.

Last trip? Hmmm, I think about this one a lot. Having done so many through
the years, a big part of me feels like I don't need to add to any
credentials. Maybe a nice long float on the West Branch from Lobster Lake on
down to Ambejejus...just to smell the home waters again. But then, I read
stuff from folks like Dave Manby and realize that my own list of rivers is
pathetically tame and trivial, so maybe some new exploration like the Coruh,
Amazon or one of those unrun gems in Siberia.

I guess, most of all, I'm glad I don't have to choose 'one last river'. But
I suspect that when I <do> run my last river, I'll have no idea that it was
the one.

--riverman
 >> Stay informed about: Devices to Measure the Speed of Flowing Water? 

"William R. Watt" wrote in message

 >

 >
  >> When I'm planning a trip on almost any floatable stretch, I bank on 4mph
  >> as
  >> the 'resting flow rate'. This might not work for smaller sections, but
  >> for
  >> almost any multiday trip, its quite an excellent constant.
 >
 > would not work on northern seasonal rivers such at the Yukon and
 > Mackenzie.


Actually, it worked quite well on the Snake/Peel/Mackenzie the last time I
was up there. We put in on the headwaters of the Snake where the flow was
less than 1 mph, and took out on the main body of the Mackenzie where the
flow was likely close to 10kph. The overall length of our trip was about 300
miles, we spend 11 days and paddled about 6-8 hours a day (excluding
portages and lunch stops). That roughly corresponds to (300
miles/(7*11)hours)=3.9 mph. While we were floating, we definately spent much
more time on a brace than a stroke, so our average speed was a good
approximation of the average river velocity.

I use this 4mph estimate when planning longer trips. If I have, say 10 days
and want to paddle about 6 hours a day, I'll expect to cover (without
portages or lots of scouting) about 240 river miles. If there are lots of
little rapids, I lower my estimate to 3mph, and would expect to cover about
180 miles.

--riverman
(But I agree with your assessment that it is only a ballpark rate, and has
lots of variations)
 >> Stay informed about: Devices to Measure the Speed of Flowing Water?