Since cfs measures “cubic feet per second” it’s a measure of the volume of the river bed as well as the speed of the current. And since rivers gather more and more water from tribs as they flow down stream, the CFS in one section doesn’t relate to the CFS in another at least in terms of direct comparison. A small trib could be roaring at 100 cfs, but the main stem might be barely moving at 1,000 cfs.
Normal walking speed is roughly 4 fps, so tossing something in the current and following it, or timing it over a distance (counting mississippi’s for a ball park guestimate), would give you a rough idea of the actual speed. As an aside, I pulled that from a civil engineering site that was discussing timing of traffic lights at crosswalks
The fish are always there, but will move to different parts of the streambed under different flow conditions. The best thing to do is get a sense of where to find fish at different cps flow rates over time--- a log will really help. And knowing at what point wading becomes unsafe for the rivers you fish is also a good idea.
You can also use fishing reports to get a good idea of conditions over time for different bodies of water. For example at 380 cfs in Reno, and 430 cfs at Farad the water is moving, and off color- perhaps a good time for streamers. Fish may have been pushed to the banks or dropped back to pools, or settled into holes on the bottom…. Look for the same current speeds you caught trout in before… only this time they’ll be in different places out of the main current, perhaps even in places that were high and dry during lower flows. The Little Truckee at 130 CFS appears to be a normal flow, and the East Walker is low at 21 cfs. So even streams in the same area can vary quite a bit, and obviously tailraces can be all over the place based on water releases:
Fishing Report - Pyramid Lake, Truckee River, Eagle Lake and more
Here’s link to USGS data, info on the Truckee is in the Pyramid and Winnemucca Lakes Basin section:
USGS Real-Time Data for Nevada_ Streamflow
Note that there is a cfs, height, and f3ps measurement. The height is a good all around measure because it will tell you where the river is compared to "normal" conditions, and is particularly good if you go to other water you're not familiar with and don't have a base line cfs to compare current conditions to. The F3PS measure is really a speed/volume measure (cubic feet) like cps, not just speed like an fps measure.
What you might want to do as a baseline, is to see if you can go back in the database to the banner day you had on the Truckee a couple of weeks ago.
If you can find the CFS data for that day, you’ll have a benchmark, since you’ll know where you caught the fish when you were being cheered from the sidelines. Similar cfs rates, fish the same spots and same lies. Then experiment with different water levels, higher water, same spots, same lies and lies with slower water within the same general area, plus some other spots with slower water. On lower water cfs , same spots same lies and lies with faster water in the same general area, and faster sections like riffles until you start to dial it in. Record date, time of day and water temp, as well as flow rate. Over time you’ll start to develop patterns, when hatches occur in different parts of the stream (time of day, time of year, what sections of the river), where to go when stream temps start edging high ( look for highly oxygenated water in or below riffles), where to head and what lies to fish under different flow rates, etc etc
Hope this makes a bit of sense...