What is a discernible green flow? I saw the phrase while reading information about BCU courses. I’m guessing it means moving water of some sort but the discernible green is vague to me.
The other stuff is white
So the green kind of stands out. Green means water that is flowing smoothly due to a lack of major interruption, and in white water it will show up between areas of literally whiter stuff that is hitting big nasty rocks.
The green flow is a much better place to be.
mean the water is flowing pretty fast? Or does dicernible mean its flowing but slowly?
When I googled "discernible green flow", the syllabus for BCU 3* Touring came up. It specifies "ungraded" rivers with "discernible green flow."
Hopefully someone else can tell you for sure, but maybe this combination of ungraded river with "discernible green" simply means it is fast enough to see (or feel) current but not complicated by rapids or eddies. Given that the alternative venue allowed is open water with Force 2-3 wind, it makes sense.
Current doesn't have to be fast for you to detect that there is flow.
heard this about guys running water falls… saying something about wanting to run the green line… or a nice pice of green water.
Gets a little more complicated
Green line in WW (and same in tidal races) is obviously moving water compared to obviously interrupted water, the situation that most in this country ever see. The green line is this situation is moving faster than what is hitting rocks, but how much faster depends on the starting speeds and how big a rocks are being hit.
Green line in BCU terminology may refer to obvious current on the ocean, for example when you can see the line of the tide moving in. Even in open ocean it tends to find certain paths as determined by the shape of the bottom. The folks in the UK get to see this usually better than most in this country due to the nature of their ocean. I suspect this is more visible in the Pacific NW than most other places because of all the islands, and if you look out offshore from Long Beach Island in New Jersey at times you can see the change in water color where the Gulf Stream has come in close.
There is a calculation for the speed of the tidal flow at each phase thru the 12 hours, actually several ways to do it, and in most places where this matters the Pilot books or local resources will have a record of typical tidal flow speeds. It can be wicked fast and easily equal to ferrying across class 2 WW like off of Woods Hole, or it can be pretty mellow. It is part of learning to paddle open water to find these kinds of resources and know how to use them.