Got it, so in other words, without knowing the specifics of the river’s width and depth, CFS is kind of a worthless metric on it’s own? I sort of figured as much. I’m used to seeing knots as a metric, which I sort of have a feel for. This CFS was new to me.
From Google maps, looks like this one is about 40-50m wide (so call it 140 feet) and apparently is only 4-7 feet deep (so maybe we call it 5.5 ft), so that’s a cross sectional area of 770. So if it’s 500 CFS that’s flowing at ~1.5 fps. So if I normally swim at ~300 feet in 90 sec (1:30/100), call it 3.3 ft per sec. I’m sure some advanced hydrodynamics come into play from here, but sounds like 1.5 fps will be a pretty strong current, slowing me to 1.8 fps or ~2:45/100m but speed me up to just above 1:00/100m downstream?
Do I swim hard like a beast upstream (maybe 9/10 effort, pace it like a 750m sprint) and then just cruise maybe 6/10 effort downstream to recovery for the bike? Will my efforts be rewarded swimming hard downstream?
There is talk of even cutting the swim in half to be down steam only, at which point I wonder if there is any sense wearing a wetsuit for a ~8 min 65 degree swim.
Based on your estimated numbers, it’s actually 0.65 f/s.
I think your approach to swim strong into the current and cruise down-current sounds reasonable since it gives you built-in recovery. Body position and technique will be far more important into a current too, and it will be when you’re fresh.