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Old July 16th 03, 06:51 PM
Eric
 
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Default Thoughts on volume (CFS) and river levels and such (sort of rambling)

Here's something to think about - and I hope someone has some good
answers or can point me to a good source of info...

We have been doing some canoeing trips as a part of a summer orientation
program here at the University of Virginia. This year we have had to be
very conscious of river levels due to an unusually wet spring and early
summer around here. (Oddly enough, we had a record drought last year -
oh well.) I have found myself spending a lot of time explaining river
gauges and river levels to a variety of people in our organization so
they have some idea about risk management.

So now I have come up with a pretty standard speech explaining classes
of whitewater, river levels and water volume. Classes of whitewater
somewhat equates to classes of rock climbs - that seems to go over well
with most folks. However, people have a difficult time with
understanding river levels (what does 5 feet on this gauge mean?). They
also seem to understand the concept of CFS but it takes a little time
for them to grasp that just because CFS doubles, level does not
necessarily double and that 3000 CFS on the Maury River in Virginia is a
good bit different than, say, 3000 CFS on the Colorado

First question - does anyone have a good explanation for what river
level is supposed to represent and a good way to explain some of the
things above without degenerating into a technical hydrodynamic discussion?

Second (and partially related question) - I'm probably missing
something obvious here but I can't see the forest for the trees. I'll
use a specific example and we can generalize from there.

Looking at the James River (VA) gauge at Buchanan, you see that the
river is at a particular level and CFS - let's say, for example, 4.75
feet and around 3800 CFS, give or take. Looking downstream, we see that
the Maury River flows into the James at Glasgow, adding its flow to the
James at that point. We see that the Maury River at Buena Vista (a ways
upstream from the confluence) is running at 4.5 and around 2800 CFS.
Now moving downstream on the James, we look at the James River at
Holcomb Rock and the gauge reads about 7.25 feet and about 6000 CFS and
change. Common sense would say (river features like dams excepted) that
part of the extra CFS would be from the water coming from the Maury.
However, the ratio of level / CFS from Buchanan to Holcomb Rock seems
to be pretty continuous, regardless of the level / CFS being added by
the Maury.

So what gives? Is this a situation that is particular to this area or
am I missing something here that is true across the board? How does the
Mississippi change when the Ohio flows in?

What do you all think?

Eric


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Old July 16th 03, 07:43 PM
D.L.
 
Posts: n/a
Default Thoughts on volume (CFS) and river levels and such (sort of rambling)

Eric-

A good point to make to beginners about river levels is to recall that
introductory physics lesson about speed and energy. As you recall the
energy of an object is the square of a speed - double the speed and
quadruple the energy. This is the most crucial element of understanding
different water levels for a beginner paddler - or a beginning driver.

Beyond that I think that CFS is best understood by experience. What is
considered a high level of CFS is a case by case, river by river, thing.
Probably the best you can do is mention the water level of the runs you are
doing and try and build the beginnings of comparative awareness - and
respect - for your class. Doing the same run twice at different levels
would also be wise- especially if you have a full semester.

If you can find a damn release run and figure out how to be at one of the
major rapids when they turn the water on that too can be quite instructive.

BTW - excellent question.

-Douglas Tooley

"Eric" wrote in message
...
Here's something to think about - and I hope someone has some good
answers or can point me to a good source of info...

We have been doing some canoeing trips as a part of a summer orientation
program here at the University of Virginia. This year we have had to be
very conscious of river levels due to an unusually wet spring and early
summer around here. (Oddly enough, we had a record drought last year -
oh well.) I have found myself spending a lot of time explaining river
gauges and river levels to a variety of people in our organization so
they have some idea about risk management.

So now I have come up with a pretty standard speech explaining classes
of whitewater, river levels and water volume. Classes of whitewater
somewhat equates to classes of rock climbs - that seems to go over well
with most folks. However, people have a difficult time with
understanding river levels (what does 5 feet on this gauge mean?). They
also seem to understand the concept of CFS but it takes a little time
for them to grasp that just because CFS doubles, level does not
necessarily double and that 3000 CFS on the Maury River in Virginia is a
good bit different than, say, 3000 CFS on the Colorado

First question - does anyone have a good explanation for what river
level is supposed to represent and a good way to explain some of the
things above without degenerating into a technical hydrodynamic

discussion?

Second (and partially related question) - I'm probably missing
something obvious here but I can't see the forest for the trees. I'll
use a specific example and we can generalize from there.

Looking at the James River (VA) gauge at Buchanan, you see that the
river is at a particular level and CFS - let's say, for example, 4.75
feet and around 3800 CFS, give or take. Looking downstream, we see that
the Maury River flows into the James at Glasgow, adding its flow to the
James at that point. We see that the Maury River at Buena Vista (a ways
upstream from the confluence) is running at 4.5 and around 2800 CFS.
Now moving downstream on the James, we look at the James River at
Holcomb Rock and the gauge reads about 7.25 feet and about 6000 CFS and
change. Common sense would say (river features like dams excepted) that
part of the extra CFS would be from the water coming from the Maury.
However, the ratio of level / CFS from Buchanan to Holcomb Rock seems
to be pretty continuous, regardless of the level / CFS being added by
the Maury.

So what gives? Is this a situation that is particular to this area or
am I missing something here that is true across the board? How does the
Mississippi change when the Ohio flows in?

What do you all think?

Eric



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Old July 16th 03, 10:28 PM
Wilko
 
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Default Thoughts on volume (CFS) and river levels and such (sort of rambling)

Eric wrote:
Here's something to think about - and I hope someone has some good
answers or can point me to a good source of info...


I think that local and overall gradient and the kind of soil or rock
through which the river cuts its way also plays a major role in
determining the difficulty level of the river/rapids.

--
Wilko van den Bergh
Eindhoven The Netherlands Europe
Look at the possibilities, don't worry about the limitations.
http://wilko.webzone.ru/

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Old July 16th 03, 11:26 PM
Fred Klingener
 
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Default Thoughts on volume (CFS) and river levels and such (sort of rambling)

"Eric" wrote in message
...
Here's something to think about - and I hope someone has some good
answers or can point me to a good source of info...
. . .
First question - does anyone have a good explanation for what river
level is supposed to represent and a good way to explain some of the
things above without degenerating into a technical hydrodynamic

discussion?

"Degenerate?" It's for explaining relationships like you describe that
"technical hydrodynamic discussions" were invented. The hydrodynamic
relationship you're looking for relates the 'stage' (which, with the profile
of the stream bed, determines the cross sectional flow area) with the flow
velocity or the total volumetric flow rate. Without going into all of the
hand waving, the velocity will vary roughly as the square root of the depth
in a broad shallow stream. You can degenerate as far as you'd you like if
you feed 'streamflow' or 'Manning equation' into Google.

Better than that, you can construct the relationship directly from the real
world flow data on a particular stream you're interested in.

Second (and partially related question) - I'm probably missing
something obvious here but I can't see the forest for the trees. I'll
use a specific example and we can generalize from there.

Looking at the James River (VA) gauge at Buchanan, you see that the
river is at a particular level and CFS - let's say, for example, 4.75
feet and around 3800 CFS, give or take. Looking downstream, we see that
the Maury River flows into the James at Glasgow, adding its flow to the
James at that point. We see that the Maury River at Buena Vista (a ways
upstream from the confluence) is running at 4.5 and around 2800 CFS.
Now moving downstream on the James, we look at the James River at
Holcomb Rock and the gauge reads about 7.25 feet and about 6000 CFS and
change. Common sense would say (river features like dams excepted) that
part of the extra CFS would be from the water coming from the Maury.
However, the ratio of level / CFS from Buchanan to Holcomb Rock seems
to be pretty continuous, regardless of the level / CFS being added by
the Maury.


Forget trying to work with stages. First, their zeros are completely
arbitrary. Second, the relationship between stage and CFS can be minutely
dependent on the particular transverse profile and bottom characteristics of
the stream on which they're reported.

So what gives? Is this a situation that is particular to this area or
am I missing something here that is true across the board? How does the
Mississippi change when the Ohio flows in?


Combining stages would be meaningless. The CFSs, though, had better add up,
unless it's raining or it's VERY, VERY dry.

hth,
Fred Klingener



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Old July 17th 03, 01:51 AM
ChuckB
 
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Default Thoughts on volume (CFS) and river levels and such (sort of rambling)

To further clarify the example about the Gauley you must look at a
couple of other things.

1) The distance between the gauges and the time when the flows (cfs)
were taken. The Belva gauge is about 27 miles downstream from
Summersville Dam. It's flow is based on what was being released at
Summersville Dam several hours earlier.

2) There are several small creeks that flow into the Gauley. These can
all add to the flow that is measured at Belva. Normally these creeks
add very little to the flow but they can make a significant difference
if their watersheds received a large amount if rainfall in a short
period of time.

It is my understanding that the level (feet) as measured by a USGS
gauge is not standardized (across many gauges). So the level on one
gauge on a river many not have anything to do with the level on
another gauge on the same river or a different river.

Flow, in almost all cases, is based on a calculation using the level
and a cross section of the riverbed at the location of the gauge.

Chuck

"EnzoM3" wrote in message .com...
Good example is the Gauley River. Gauley at Summersville is what's coming
out of the dam. Then the Meadow add it's flow, and downstream at Gauley at
Belva is pretty much the sum of the Meadow and Gauley at Summersville.

Jim



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Old July 17th 03, 04:25 AM
Felsenmeer
 
Posts: n/a
Default Thoughts on volume (CFS) and river levels and such (sort of rambling)


"ChuckB" wrote

It is my understanding that the level (feet) as measured by a USGS
gauge is not standardized (across many gauges). So the level on one
gauge on a river many not have anything to do with the level on
another gauge on the same river or a different river.


That's correct- the level is based on a somewhat arbitrary datum, thus "5
feet on the gauge" just means that the level is 5 ft. above the datum. The
datum is tied to sea level, so you might have a datum of 0 at 800 ft. above
sea level, so when the gage is at 5 ft., the water surface elevation is at
805 ft. MSL. 0 ft. does not equate to the stream bed either, in many (if
not most) cases.





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Old July 17th 03, 05:12 PM
D.L.
 
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Default Don't Post to This Thread

I've received a rather strange reply from the originator of this thread
which clarifies the real intent of the original, 'rambling' post. Although
the question is still good - the reason for it is intentionally misstated.

I've challenged the guy privately in response to his e-mail and I'll wait
for his response today before I post the rest.

But do take the warning that this guy is a risk to both his students and
perhaps even yourself.

-Douglas Tooley
"Felsenmeer" wrote in message
.. .

"ChuckB" wrote

It is my understanding that the level (feet) as measured by a USGS
gauge is not standardized (across many gauges). So the level on one
gauge on a river many not have anything to do with the level on
another gauge on the same river or a different river.


That's correct- the level is based on a somewhat arbitrary datum, thus "5
feet on the gauge" just means that the level is 5 ft. above the datum.

The
datum is tied to sea level, so you might have a datum of 0 at 800 ft.

above
sea level, so when the gage is at 5 ft., the water surface elevation is at
805 ft. MSL. 0 ft. does not equate to the stream bed either, in many (if
not most) cases.







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Old July 17th 03, 05:38 PM
Eric
 
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Default Don't Post to This Thread

Mr. Tooley -

I'm not exactly sure what you are trying to say here. Are you implying
that I don't know what I'm talking about and I'm not in the position to
defend what goes on in my program? Because if that is the case, then
you are sadly mistaken. We have some very clear policies about how we
go about running our program that are firmly rooted in industry best
practice. Additionally, we spend an appropriate amount of time with our
staff training them to do the job we ask them to do.

My question was posted in good faith to gain some different perspectives
from the resources out there in the rec.boats.paddle newsgroup. I have
posted information in answer to questions there in the past and have
gained valuable information by posting questions to the newsgroup as well.

My question to you - What ARE you trying to suggest here?

Regards,

Eric Henkel

Mr. Henkel-

To be frank, given your non-ability to follow through on your original
question, I have to doubt your ability to accomplish your task. As far
as I can tell this post is nothing more than elaborate attempt to cover
your ass against educational administrators who have institutionalized
this trait.

You should either resign, or take responsibility for yourself, with all
the risks that entails.

You have today to try responding again. Elsewise I post your reply to
the newsgroup, with similar comments.

-Douglas Tooley

-----Original Message-----
From: Eric Henkel ]
Sent: Thursday, July 17, 2003 8:03 AM
To: D.L. Tooley
Subject: Thoughts on volume (CFS) and river levels and such (sort of
rambling)

Douglas -

Thanks for the answer. Unfortunately, it's the experiential thing
(learning by being on the river) that I can't use. I'm trying to
find a good explanation for folks in our administration and they
don't seem to want to take the time to go paddling (I don't know why
- doesn't make sense to me! )

Having been a raft guide on the Ocoee, I know that even 100 to 200
extra CFS can make a big difference in a river. However, I'm just
having a hard time translating to non-paddlers.

Thanks again,

Eric
--
__________________________________________________ _________
Nothing is more terrible than activity without insight.
-Thomas Carlyle
__________________________________________________ _________
Eric Henkel
Director, Poplar Ridge Experiential Learning and Training
Assistant Director of Outdoor Recreation
"Soon-to-be Daddy-O"
University of Virginia -- Department of Intramural Recreational Sports
450 Whitehead Road; PO Box 400317
Charlottesville, VA 22904-4317
Ph: 434-924-3791
Fax: 434-924-3858
http://www.virginia.edu/ims



D.L. wrote:

I've received a rather strange reply from the originator of this thread
which clarifies the real intent of the original, 'rambling' post. Although
the question is still good - the reason for it is intentionally misstated.

I've challenged the guy privately in response to his e-mail and I'll wait
for his response today before I post the rest.

But do take the warning that this guy is a risk to both his students and
perhaps even yourself.

-Douglas Tooley
"Felsenmeer" wrote in message
. ..


"ChuckB" wrote


It is my understanding that the level (feet) as measured by a USGS
gauge is not standardized (across many gauges). So the level on one
gauge on a river many not have anything to do with the level on
another gauge on the same river or a different river.


That's correct- the level is based on a somewhat arbitrary datum, thus "5
feet on the gauge" just means that the level is 5 ft. above the datum.


The


datum is tied to sea level, so you might have a datum of 0 at 800 ft.


above


sea level, so when the gage is at 5 ft., the water surface elevation is at
805 ft. MSL. 0 ft. does not equate to the stream bed either, in many (if
not most) cases.













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Old July 17th 03, 06:10 PM
D.L.
 
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Default Don't Post to This Thread

Your original post stated you were looking to explain things to your students. In your private letter you belittled my freely given response and let slip at least some of your original intent in your vague and poorly worded original inquiry.

I am aware that Outdoor recreation leaders have an unclear status on campus - somewhere above many staff members, but below most faculty. My empathy for the politics you suffer on campus, but you should either confront those problems or leave, not foist them off on others, especially your students.

My original, private request still stands. Please make your intent with this post completely clear.

The only thing that is personally attacking you is yourself, and it appears quite rightly. I am explicitly challenging your professional qualifications as a river guide, as an educator, and as a public employee based on this thread.

Would you like me to explain that to you again?

-Douglas Tooley
"Eric" wrote in message ...
Since you don't know me as an individual, please take the time to clarify your questions before making an accusation such as this one.

You have never been on any sort of river with me or worked with me in any of the programs that I have spent time at in my 10+ years in outdoor education and recreation.

I asked for simple information. I received some good answers. However, I now find myself being attacked on a personal and professional level for reasons with which I am not entirely clear.

If you have questions, please contact me personally and do not attack me in a public forum unless you can be sure of what you are saying.

Eric Henkel

D.L. wrote:

I've received a rather strange reply from the originator of this thread
which clarifies the real intent of the original, 'rambling' post. Although
the question is still good - the reason for it is intentionally misstated.

I've challenged the guy privately in response to his e-mail and I'll wait
for his response today before I post the rest.

But do take the warning that this guy is a risk to both his students and
perhaps even yourself.

-Douglas Tooley
"Felsenmeer" wrote in message
.. .
"ChuckB" wrote
It is my understanding that the level (feet) as measured by a USGS
gauge is not standardized (across many gauges). So the level on one
gauge on a river many not have anything to do with the level on
another gauge on the same river or a different river.
That's correct- the level is based on a somewhat arbitrary datum, thus "5
feet on the gauge" just means that the level is 5 ft. above the datum.
The
datum is tied to sea level, so you might have a datum of 0 at 800 ft.
above
sea level, so when the gage is at 5 ft., the water surface elevation is at
805 ft. MSL. 0 ft. does not equate to the stream bed either, in many (if
not most) cases.









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Old July 17th 03, 06:14 PM
Eric
 
Posts: n/a
Default Thoughts on volume (CFS) and river levels and such (sort of rambling)

My reply contained herein (and earlier in the changed thread as well -

BTW - this is cut from my original post -

"I have found myself spending a lot of time explaining river gauges and
river levels to a variety of people in our organization so they have
some idea about risk management."

I did not say that I was teaching a class or specifically say that I was
talking about students when I was actually looking for information
specifically for administrators.

D.L. wrote:

"Eric" wrote in message
...
Maybe I should stop trying to explain things to risk managers /



administrators and just go paddling instead! Which is what I plan to do
this weekend.



I thought you were asking us about your students. The answer for
bureaucrats in a legal/liability situation is adifferent kettle of fish.
Your attempt to hide your motivation only leads me to wonder what else you
are hiding. Did you have an injury on one of your trips?


No, there has not been an injury in our program. There has merely been
an ongoing effort within our organization to make sure that people on
all levels (participants, instructors, program directors,
administrators) have an understanding of what we do in our program and
why we make the decisions we do. This would prevent someone from making
a statement like "Oh, the river is only at 5 feet. That can't be too
deep - go ahead and paddle it." when they know nothing about
hydrodynamics. It's no different than me sitting in a weekly meeting
and asking questions about Automated External Defibrillators when it
does not have specific bearing on my program area.

It's basically a question about trying to find an easy way to explain
paddling issues to non-paddlers.

Combining stages would be meaningless. The CFSs, though, had better add

up,


unless it's raining or it's VERY, VERY dry.



Don't forget the groundwater part of the equation. Groundwater can either
add or subtract from flow levels and is a bigger factor than evaporation,
unless you have a major lake or reservoir. Groundwater tends to be a
seasonal factor. Here in the West where we receive most of our
precipitation in the Winter the cycle goes like this:

Fall Groundwater replenishes - decreased runoff
Winter Ground saturated - increased runoff - to snow level
Spring Ground saturated - increased runoff combined with snowmelt
Summer Groundwater runoff contribution gradually declines.

Groundwater is also affected by recent years precipitation and will be
decreased following a period of drought.

-Doug




Also makes sense here - although we had a drought last year, we have had
a much wetter spring than normal that has saturated the groundwater
table. Thus, when we have some of the violent thunderstorms or remnants
of tropical storms that roll through Virginia, water levels can elevate
rather quickly.

Eric



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