Sounds logical as the width of the river also changes. The USGS for our location i believe only tells me gage height and I’m not sure if the dam even reports water release as it is normally slow. I can see the lag in the graphs after a large rain though compared to a small rain. Most people on this river are not to concerned with speed they just want to make sure they can get thru without dragging boats.
I am very thankful to have the data and ironically I would bet that if I asked 100 people on the river I could count on one hand how many even know about it.
Most guide books can give us some idea when high flows become flood stage and become more dangerous.
I have run a lot of rivers at high flows, but only once got into some trouble on the John Day River in Oregon in canoes at 6,600 cfs.
I agree with ppine here… Guidebooks and knowledge obtained from local paddlers are probably the best ways to “interpret the numbers” for any particular river. But the USGS data collection system is a tremendous resource that is available to all for free and yet many paddlers don’t seem to know about it or utilize it. There are automated stations that collect data on most waterways and relay it by satellite (15 min intervals if I recall correctly) where it is continuously updated. Nation wide you can go to: https://waterdata.usgs.gov/nwis/rt
Click on the state that you’re interested in and a map of all the stations in that state will come up with the stations locations indicated by colored dots. The color indicates flow rates as a percentile of the computed rates for that date based on at least 30 years of record. Click on the dot nearest to where you wish to paddle and you’ll get the recent data for that station.
Though I don’t do this often, you can also call up gage height and discharge for particular dates in the past as well - like if you want to know what the numbers were on that trip you did two years ago.
The graphed trend lines are useful, too. For instance, on my home river in the records I’ve seen for this river, I’ve never seen a rise of more than 2’ in 24hrs. So I can feel confident that if I pitch camp 2’ over the water I can count on not being flooded out of my camp if I only stay for 12 hrs. Other rivers are, of course, different. On the Jack’s Fork, for example they say 8’ over river level is safe for an over night camp if you have a “back door” escape route. WAY different.
This kind of info can be “gold” for planning a paddle trip.
I’m sure most of the old-timers here know about this, but it never hurts to spread the word for the benefit of those who may not.
Good to post this info. Those of us that use it all the time take it for granted, but not everyone knows. You can also just google water level for many rivers and the USGS data will be in the search results. Not everyone thinks of doing that either.
thanks to PJC for mentioning the USFS gauging system.
One other thing to consider is the operation of dams.
We were camped on the Snake River above Boise, in the “Birds of Prey” section.
It was a warm summer night and we were near the waters’ edge. My sleeping bag got wet about 0300. The pots from dinner were floating. We put our outfit in the canoes and headed for higher ground.
The upstream dam had released water due to electrical demand by air conditioning over night. The water rose about 18 inches in a few hours. Not a cloud in the sky. Remember that paddleheads.
Somewhat similar story. Years ago we were camped in the Ohiopyle campgrounds with plans on rafting the Youghiogheny the next morning. It was a beautiful night not a drop of rain. What we didn’t know is there was a huge storm between us and Confluence where the dam is. We started down to the outfitters and were told the river was closed because of some rain up stream. We got mad and went down to take a look. We all got happy it was closed pretty quick when we saw the waterfalls was no longer there in its place was a raging brown torrent that looked like it would drown us in a minute.
I don’t know what the numbers were and they at that point were meaningless.
No hard-and-fast number limits for me. The combination of all variables creates too much range in combined risk levels to use such a simple rule.
I use qualitative factors more than purely quantitative ones:
Solid water = No go, no matter what.
Too cold to paddle without wearing gloves = No go, by choice.
Electrical storms likely or happening = Get off the water ASAP or don’t go in the first place. We have a lot of these in CO.
Wind = I actually enjoy paddling in wind now. But the limit is what speed wind can I carry my surf ski to and from the water, and THAT depends on wind direction and exposure at the launch. Logistics of where I paddle rule out using a portage cart or leaving boats unattended.
Tidal factors = Not relevant in this area. But I used to study and write down all the times of max ebb and flood for various points in my route, when I lived at the sea. The only place where flow speed could reach levels I would not fight against was out in the shipping channel, where I never went, and around an infamous point, where I did go but chose my times carefully.
Gage readings need to be combined with local knowledge to be useful. The same gage reading on different rivers may indicate a raging torrent or a horizontal rock garden. Some sites will have information that gives some indication as to the navigability and degree of difficulty for boating for different gage readings, but not all…
Bud, do you know about this resource, the automated USGS data harvesting master spreadsheet with optimal readings for canoeing and continual updates of the gauge levels on PA rivers? The French Creek runs start at line 265.
Thanks I haven’t seen the list page. I have been using the USGS page with the graphs mostly and knowing from past experience what gage heights relate to the areas we go down.
