river flow to MPH?

If a river is flowing 4060 cubic ft per second, how many MPH would a canoe travel?

At 4060 cu.ft/sec., would that be too dangerous to canoe in?

Totally depends on river size
This amount of flow being considered SAFE is totally dependent on the river in question. For a small creek-sized river this very well could be dangerous but for a large broad deep river, this could be a very low level with very little velocity. Getting a velocity (mph) from mass flow rate (cfs) requires a knowledge of the size of the river,… both width and depth. The Mississippi River doing 160,000 cfs will be moving slower than the Glover River in Oklahoma doing 1,000 cfs. Which river are you talking about?

It does not translate at all.
The flow in cfs figure measures the VOLUME of water going by a given point in one second, NOT the speed. Speed is determined by the gradient–how much the river drops in elevation over a given stretch–with some modifications from the volume. And the speed at any given point may be very different from the speed at a point just a few feet upstream or downstream.

There is also no way to tell you whether your flow in cfs makes the river dangerous or not, unless you know a lot more about the river. 4000 cfs may be a low and slow flow on one river and a very high and very dangerous flow on another.

Go back to your gauge page and look at the table labeled “daily discharge, cubic feet per second…”. Look at the figures. The median flow figure is more or less the normal flow for that stretch of river at that particular day of the year. The 25th percentile figure means that only 25% of the years of record was the river flowing less than that figure on that day, and the 75th percentile figure means that 75% of the time the river was flowing less than that. The 75th percentile figure is usually somewhere around the highest the river could be and still be floatable without too much danger, BUT that varies depending upon the characteristics of the river, too. If your river is normally quite placid, a flow close to the 75th percentile might still be reasonably safe, but if your river is fast and filled with obstructions even at normal flows, a flow near the 75th percentile will probably be far more dangerous.

minnesota
the minnesota river between North Redwood and Morton. Its a few feet above normal. I saw 3 canoes going down it today, but the water seems to be moving very fast and strong. The currents are swirling around quite a bit.

I think I’ll wait a couple weeks. I dont have much experience on this river.

Good to see …
someone who understands CFS. I’ve tried several times to explain CFS on this forum, even going so far as to discuss how it is calculated and find most folks still do not get it.

Get on the river, try it out going
forward, and then spin in around and try backwards.

Subtract.

Good judgement is key
Always trust your gut instinct and lean towards caution if it looks a little dangerous. I would also give the river a little time to “settle down” in that case. American Whitewater website has a good flow scale for particular river sections all over the country for the purpose of scaling river difficulty. It is color coded for easy understanding and worth a look. Also some river sections are actually easier at higher flows where exposed boulders and obstructions are submerged so its not always a linear scale of “higher flows =greater difficulty”

Whoa!
If I understand this post correctly, I urge anyone reading this forum NOT to embrace this approach. This idea is just bravado. My personal philosophy is 1000% diametrically opposite. I never get on a river without doing some homework. Some put-ins on pool drop rivers are located in still pools for obvious reasons, then 100 yards downstream is an unseen killer rapid. IMHO the best way is to find local paddlers with a lot of experience on this river and converse with them. I’ve hardly ever met one who wasn’t willing to share. Even to the most skilled paddler in the world, advice on running a specific rapid is priceless. What could be a fun run can turn into a real headache without some knowledge of inherent dangers of a dicey rapid. Have fun but be safe.

Pag

ill wait
Its a big river. Moving too fast for my liking. I want to enjoy a relaxing ride downstream. Looking at the landing, I cant imagine how you’d be able to stop the canoe, jump out, and pull the canoe out. Water is rushing by.

Something tells me my canoe would end up in New Orleans.

Good call
whirlpools are indicator of fast water.

Sounds like you have good judgment.

Oops
I posted my last message in reply to Ezwater’s comment, above. It somehow got put under another post.

Sometimes they go where the computer gods deign, not where posted.

Pag

No, it’s in the right spot.

– Last Updated: Jul-27-14 2:43 PM EST –

Yatipope placed his post as a reply to that of ezwater before you did, so your post is below his. You need to look at the amount of *indent* to indicate what post has been replied to, and which post ends up above or below, within that particular indent category, is only a matter of timing (just as is the case for non-intended replies to the original post).

Half the people here have no clue how this works, and it only messes things up, or at best, leaves room for confusion about who's trying to say what to whom, but you DID put your post in the correct place.

While I'm at it, could you tell that ezwater was joking?

You’re prudent.
I looked at the Minnesota River at Morton gauge. I am only very superficially familiar with the Minnesota…have seen it in several places but never been on it. But, as I said above, you CAN learn a lot from the gauges if you know what to look for. In the streamflow table (not the graphs), you’ll see that today’s median flow for the Minnesota at Morton is 1190 cfs. That’s the normal flow for this date. The 75th percentile flow is 2670 cfs. Knowing nothing else about the river, if I saw that it was flowing significantly more water than that, I’d stay off it. What it was actually flowing a half hour ago was 4020 cfs, and that IS considerably more than that 75th percentile figure. So you are smart to stay off it.

That general rule of thumb has served me well over the years on unfamiliar rivers, but like I said, it isn’t a hard and fast rule. Nothing is better than actually being familiar enough with the river to know what it’s really like at a given flow…and nothing works better than, if you’re looking at it and feeling at all unsure, STAY OFF IT unless you’re with somebody who IS intimately familiar with it.

well
when I replied to EZ’s post there were no others below it. I hit reply directly under that post. And no I did not know EZ was joking. The Op was asking a serious question and obviously did not know what CFS means and sounds like some serious water is involved, so that is not a time to be joking. EZ holds himself out as a self styled expert and the unknowing might take it seriously.

water speed
Thanks to al a for a good explanation. I used to do stream gauging for a living with Price and pygmy meters. You can estimate velocity by measuring the time an object takes to flow a known distance. An orange works great. It floats and you can see it.

The gradient in feet per mile is really important in figuring velocity. As rivers gain flow they gain velocity because there is less friction in the streambed. Pool and drop rivers are more difficult at the same velocity as smooth gradient rivers. There lots of variables to consider which is why there are so many guide books.

Track the discharge in cfs for the river you are interested in and find a table that shows the gauge height for each discharge level. Then check the gradient. Guides books can show you recommended flows.

Joking on pnet, choking on high water.

Also
I’ve used those puffed rice cakes as surface velocity markers. Timing them traversing under a bridge of known width gives a reasonable surface velocity estimate. Plus, they disintegrate relatively quickly - and who wants to eat them anyway?