If you fish rivers, or kayak, or canoe them, you may know about the USGS river gauges. They are scattered up and down the navigable rivers, and you can see their information on the internet in real time.
You can find links to some of them here on FishExplorer when you check out a river or lake. Or you can go on-line and search out any that you want to look at.
For instance, let's say you are thinking about fishing the Llano River. Go to your favorite search engine and type in "Llano River Gauges" and you'll get several hits. Starting with "Llano River at Llano". Click on that and it takes you to the chart that shows how high the river is running, and how many cubic feet per second is flowing, in separate charts.
The search also returns a gauge near Mason. On the Brazos there are half a dozen gauges. Each river is different in the number.
The National Weather Service also uses the same gauges but puts out a better graph, at least in my opinion it is a better chart that is more readily understood and combines all the data into a single chart and also shows the flood stages for a point of comparison.
The NWS charts also have location maps so you can see exactly where the gauge is.
The NWS chart page also includes a link (further down below the chart) to upstream and downstream gauges.
You can do some predictive work with these gauges. I can, for example, get a fairly good idea of how much water is moving down the river towards my location by looking at the gauges upstream of it. This can be handy if you are planning a trip a few days out and want to see what the river might look like when you get to your location.
Below is an example of what the NWS charts look like.
seang, TX 11/13/2018 10:10:49 AM
I was wondering if you could estimate the water speed in MPH on the brazos in your area right now. i know it could fluctuate on depth and width, but just a ballpark in your area, mayby 3-5 mph?
Lloyd Tackitt (Lloyd Tackitt), TX 11/13/2018 1:07:23 PM
It is flowing by my house at the rate of 18,000 CFS. Assuming the river here is 200' wide and 20 feet deep then a one foot wide strip across the river would hold approximately 4,000 CFS. So the flow rate should be 4.5 FPS (dividing 18k by 4k) and that equates to 3 MPH. Assuming my assumptiions are correct. That would be about my guess.
Lloyd Tackitt (Lloyd Tackitt), TX 11/13/2018 1:09:18 PM
4,000 CF not CFS.