How to find the current of a river?

I'm sorry if this is a silly question, but as a new kayaker I am not clear about this information. How do I know if a river is going to be easy to kayak? I can find the CFS for many rivers, but how does that translate to how strong the current is going to be? My very basic understanding is that current is going to be CFS/area of the river, so depending on how big the river is a large CFS may or may not be a strong current. Is there any measurement that takes this information into account? Plus I know a lot of rivers here are tidal influenced. I'm hoping for somewhere I could look at a number and be able to say "today is a good day to kayak the Sacrament up and down river, I will go today". Could anyone help walk me through this process? For ocean fishing I am looking at wind, swell and tides. What information should I be looking at for rivers? Please point me to this information if it is on the website already, I do try to research before asking questions.

If you are Bay Are based most rivers are controlled by dam flows.

Think about hiring a guide for where you want to go.  I'm not sure if there are any yak guides for the Sacramento, but any legitimate guide who runs the areas in question would be able to instruct you on when, where and how you would be able to safely navigate the river at different flow levels.

I've spent a fair amount of time over the past 10 to 12 years on the lower Klamath - both guiding and on personal recreation trips.  It has pretty high base flows (2 to 4 thousand CFS), but it's a big river.  I've paddled up from Klamath Glen eight miles to Blue Creek in late summer flows - got out eight or nine times to pull around riffles on edge water.  You're correct in your consideration that comparing CFS to overall area is a good place to start, but on the ground (on the water...) knowledge will be vital to what you're trying to determine here.

If you can't find a guide or experienced buddy to help you check this out, you might research where you can launch and land for a point to point downriver run.  In that situation you'll be able to determine how feasible it may be to paddle upstream, keep your position...etc.  With the big levees it may be impossible or impractical to get out and pull around a riffle like I can do on a big river with gravel bars like the Klamath or Eel.

Good luck - let us know what you find out.

I use this resource to check where gauges are at, then u can just search "flowrate on ___ river near (place)" and get ur data.
https://dashboard.waterdata.usgs.gov/app/nwd/?region=lower48&aoi=default

example of a search "mad river flow rate near Arcata" https://waterdata.usgs.gov/ca/nwis/uv/?site_no=11481000


But dito what eric says, rivers are nothing to F with.

Ive done some eel river trips w eric which were awesome. Then I did a guided boat trip on my local Mad river to scope any hazards, then i got the balls to do it myself. Ended up still rolling my yak and losing gear. Not fun. AND SKUNKED

get a guide, ask them what proper flows look like, maybe they will share river stage height or flowrates with you.

You can look up CFS online, but each river's CFS is not equal to another's. And not each section of river is created equal either, you really have to plan whether you plan to float and do a pickup, or if you can paddle back to your original launch, or ride tides or anchor up. Knowing what constitutes "safe" or not is really dependent on a lot of factors like river width, depth, hydrodynamics of your kayak, and whether the flow is uniform across the entire width of the river or if there a lot of eddies or slower portions along the bank that can be paddled against. The most important factor no matter the plan is getting to the water and observing surface flow conditions, and being prepared to abort if things don't seem right.
I've consulted some of the headwaters staff in Redding for lower sac flows between redding and red bluff, and my comfort level is anything less than 10,000 CFS for a float or less than 3500-4500 if I plan to anchor or paddle back up. If it's the lower sac (below Shasta), then the headwaters staff know best as the shop is right off the river and they paddle almost every day during the summer for Sundial trout. The shop also offers seminars every now and then on the Sac specifically. The sac really isn't anything to mess around with if you don't know 110% what you're doing. After several float trips and experimenting paddling/pedaling back up the sac I determined what my own comfort level is. I've done the Feather for striper on low flow years during the summer and done just fine, but the CFS then was in the hundreds, a trickle compared to what it should be. Touring kayaks that are very slim profile and hydrodynamic navigate upstream the lower sac (redding) at 7500 CFS (normal during salmon season), but I struggle to even hold against the current let alone paddle upstream in my revo in those flows. Same for touring kayaks 5500 CFS in sac metro area, although I've done fine from Garcia bend in sub 4000 CFS. But the only reason I know that info was from observing touring kayaks paddling with ease firsthand, and firsthand experience in a powerboat. My general rule of thumb is if the surface flow is >1mph at the fastest portion, it's a no-go for the hobie unless I plan to float trip. I prefer the surface water to be as lake-like as possible if I'm solo. But others' mileage may vary.

Awesome info guys! Thanks for all this. I am coming to the conclusion that I'm not ready for rivers yet. I have the opportunity to observer the Sacramento almost everyday in Old town during my lunch break. I'll start by comparing my observations to the posted flow rates. I'll continue to research potential float trips and look into maybe some guide services.

Since you're in Sac:

In the early 00's, I'd paddle from Howe up to Watt, or further. This was in fast touring sea kayaks, and felt it a point of pride to be able to get through the "rapids" just downstream and under the Watt bridge. Ditto for the "rapids" that allowed me to get from the stretch above Watt up into the Riverbend area. Of course over the past 20 years, it's entirely likely the riverbed has changed, so who knows how it will paddle now. However, back then, it was class 0 for big stretches of the river, and class I "rapids" in the "difficult" sections. In those fast sections, I'd be making 6"-12" of headway per stroke, and could take several minutes to move the 50-100 yards.

As for easier water: starting at Howe, for instance, you could paddle downstream until you see where the current picks up, turn around, then paddle back up to Watt, turn around and take out back at Howe. A very beginner friendly stretch of river.  That said, I'd make your first bunch of outings paddle only, until you get used to kayaking in current. A good current will push your boat around pretty well, and it's not all that hard to sink an upstream edge and wind up upside down.  Dress accordingly and wear your PFD.

Thought I'd post these for what it's worth. First video is of "Lake" Redding, has pretty mean flows at times but it's a tad slower and a bit safer than the main sac stem. Second video is somewhere around the colusa area I believe. Shows just how easy it can be to get stuck in a sticky situation.
https://www.youtube.com/watch?v=MfOJnfhsUPQ&ab_channel=Mr.Markus

Thought I'd post these for what it's worth. First video is of "Lake" Redding, has pretty mean flows at times but it's a tad slower and a bit safer than the main sac stem. Second video is somewhere around the colusa area I believe. Shows just how easy it can be to get stuck in a sticky situation.

That second video is a very good example of how boaters die in current. Let's see - a strainer with potential for foot entrapment, as well as the potential for the boat to pin you against the strainer or pin you underwater.