no
Gauges that read in feet and inches really have no absolute meaning whatsoever, and only give a relative indication of water levels. That gauge might be situated in a pool on the river. That pool could be feet deep even when there is virtually no flow downstream and the river bed could be nearly de-watered.
The level will only have meaning to those who know the river.
correct
I am always dragging in the shallows and riffles where others are not. Just can’t help it that I’m a big guy. Pick your lines carefully but sometimes that is not enough in low water situations.
Brian
Time for some quibbling
– Last Updated: Jan-27-12 3:58 PM EST –
You calculations are way off - not even close. I think your understanding of the situation is illustrated by the fact that you calculated that initial waterline depth to a degree of precision that's about equal 1/10th the thickness of a human hair (and your incremental increase in waterline depth is calculated to the same order of magnitude as needed to measure the diameter of a human hair), but in any case, it seems that you are assuming that a canoe is rectangular block. However, if you define it only by length and width its volume is roughly much less than what it would be if it were a rectangular block. Also, its effective dimensions are constantly increasing as the boat sinks deeper, so the relationship between increasing load and waterline width is not linear as you made it out to be. Here's a pretty typical 17-foot canoe:
http://www.bellcanoe.com/products/default.asp?page=product&id=593&catid=194
Note that 850 pounds is far in excess of the load they even considered worth figuring out the waterline depth for, but it looks like it would make the canoe sink three times deeper in the water than the figure you provided. Some canoe makers list maximum load capacities in the range of 800 to 900+ pounds, but they are assuming that a canoe that has 6 inches of freeboard is okay for normal use, but as has been discussed many times on this site, that definition of maximum load makes no sense. I see that the six-inch freeboard load is listed for this canoe, but since they don't call it a "maximum load", I'm guessing that the only reason it's there is so you can compare this canoe to those made by some other makers.
By the way, going faster through shallow water makes the rear half of your boat sink deeper. It can't be avoided because going faster reduces the water pressure applied to the rear half of the boat. It might have something to do with Bernoulli's effect too since the squatting of the rear end only seems to get worse in shallow water. I paddle the Wisconsin River a lot, and at low water levels one can barely squeak by the tops of the sandbars. When that happens, the thing that will float your boat through the absolute shallowest water is to drift the same speed as the current. When you are right at the edge of bottoming-out, the the slightest speed of travel through the water will make you scrape bottom, where drifting with the current will let you sneak through. Even if going faster were effective, how would you do it if you can't plant your paddle?
River Gauges
– Last Updated: Jan-27-12 2:17 PM EST –
Others have pointed out that river-gauge readings are arbitrary, and unique to each river. Think of it this way. Most gauges date back to a time, perhaps even 100 years ago, when someone wanted to keep track of the river level. Often all they did was nail a wood stick with markings on it to the side of a bridge piling. That first gauge usually didn't have "zero" at the bottom of the river at that location (although setting it up that way is possible). Instead, the "zero" end of the stick only needs to be deep enough that the water won't drop below it, but even that sometimes happens. In any case, the "zero" elevation established by that first arbitrary gauge usually ends up being used forever more.
Went on a field trip today…
Thanks to everyones replies on here I went out today to try to get a closer look at things. I found the USGS stream guaging station, it’s about 10 miles upstream from where I live. I followed the river and stopped at a about a dozen spots to get out and check it out. The river channel looks almost identical that whole 10 miles. It’s narrow, twisty, and fairly steep banked. At most places its probably only about 30 feet wide. I couldn’t tell anything about the depth though because it’s pretty icy right now. There is a pretty fast moving current along one bank, but it’s probably only about 8 feet wide, then it’s iced over to the other bank.
I understand a lot more now about how you have to just know the river to get any useful information from the stream flow charts. You have to have something to base the numbers on.
Air-photo field trip
I just looked at several miles of that river upstream of the reservoir, via air photos on two different website. On one site I could clearly see the submerged sandbars, and it was difficult to tell if the water would be deep enough at all locations, but on the other site it definitely looked okay. Both sets of air photos were taken at a time of year when the trees were bare of leaves and no crops were in the fields. A closer look might show whether it was spring or fall, but right now I don’t know. One thing that worries me is the huge amount of irrigation going on in the surrounding farm country. That’s often a cause for rivers to carry much less water than what’s natural, and is a good reason to be concerned about how much water will be present in summer. The gauge-reading history might help you figure that out, but nothing beats a first-hand look at the river at various times of year.
USGS guages
– Last Updated: Jan-28-12 9:21 AM EST –
You will note that that USGS gauge, like most, gives a reading in feet and a flow reading in cubic feet per second (CFS). The CFS reading will probably give you a better feel for whether the stream is runnable at the current level.
A relatively wide, shallow stream bed is going to require a lot more flow to ensure enough depth to paddle it without hanging up than will one which is relatively narrow and steep banked.
My guess would be for a narrow (30 feet or less) stream bed with relatively steep banks(suggesting greater channelization and depth in the main flow) 150 CFS would probably be enough to paddle the stream without hanging up too much.
Stream beds are not uniform, however. In places the stream might flow over a uniform, shallow shoal or river wide ledge. If the 150 CFS of flow is distributed uniformly across the entire width of the stream bed, it might not provide enough depth to float.
on another note…
On of the beauties of a canoe is when you do get into water\shoals\riffles\runs too shallow to paddle you simply step out and line or float her thru and step back in. Periods of shallow water probably wont preclude you from paddling just gives the stream summer character
Republican River…
Thanks for checking things out for me guys! I have not lived here long, and don’t know many people here. The Republican River has a history of canoeing and tubing below the dam, east of the reservoir. I’ve read that the best time is July and August when they release water from the dam. Here is a link to the Nebraska Game and Parks Canoe trail, the section described is the 49 miles downstream from the dam.
http://outdoornebraska.ne.gov/boating/guides/canoetrails/canoe-rep.asp
The river looks very different downstream from the dam, than it does above. Downstream it is wide and braided. I’ve searched and searched, their are no guides around here. I’ve never heard of anyone canoeing upstream from the reservoir. Of course, canoeing doesn’t really seem to interest anyone around here. I have seen a couple of houses with old canoes in the backyard that look like they have not moved in a long time. Just about everyone that lives here has a big motorboat though.
sure be optimistic…its good
but the Moose River that goes to James Bay actually ends for a while in low water.
35 miles of mostly walking and dragging across sand bars and dunes with no water coverage.
Other rivers like the Buffalo sometimes do the same. The Buffalo has a significant underground channel…tough to paddle there.
The Allagash also turns into a nasty hiking trip in very low water.
Ah Hell
Just go for it! If ya gotta walk a little it’s all in the adventure. Hell, I dragged my canoe for over a few miles of ice once upon a time and made it just fine! Makes for a good story and a lesson learned!
dougd
actually no
Mainly I was being sarcastic with no backing of mathamatical calculation…other than the forward wake comment.
I was basically saying "get out and paddle, learn the river, the water, you dont need 2.5 feet of water.
I failed math in college but Ive paddled now for 45 years and a lot of places.
Have fun!
thats nice
You can paddle in the heat of summer, alot of streams shut down during the height of summer unless alot of rain falls. Good luck, wear sun screen.
Ryan L.
Got that right 
You need…
some lessons in reading river gauge info, but mainly you need to look at the river when it’s not half frozen in several different spots. However…river gauges:
The level in feet tells you nothing until you’ve paddled the river enough times to correlate level to paddling conditions. I wish more people would ignore the river level in feet and use the flow in cubic feet per second, because that IS a finite number which can be compared from one stream to another. The other thing you need to look at on the gauge page is the median flow in cfs for that date. The median flow for, say, March 1, is the number of cfs that on half the years of record for that gauge, the river was flowing more than, and half the years it was flowing less than. Basically, median flow (which is also shown as little triangles on the flow in cfs graph) is the “normal” level of the river for that day. You do not want to be on the river if it’s greatly above normal, because that can be dangerous.
On the rivers of the Ozarks that I paddle, if the flow is somewhere near normal and it’s flowing over 100 cfs, it’s pretty easily canoeable without a lot of dragging. With a wide, flat, sand-bottomed, braided river, 150 cfs will probably mean you’ll drag or have to walk the canoe through some of the braids…and with the few sand-bottomed rivers I’ve floated, you might possibly encounter soft sand bottoms that are difficult to wade through, or even quicksand. On the other hand, a narrow, winding, sand-bottomed river that’s mostly not more than 50 feet wide, 150 cfs would probably give you plenty of water. On a fast-dropping, rocky river, 150 cfs will require a lot of technical maneuvering.
But the only way you’ll find out for sure is to paddle it. Just like I said before, pick a time to try it when it’s somewhere near that median flow, and do not try it when it’s flowing considerably above the median.