On American Whitewater I see a lot of rapid classes with parenthesis’s ex. I-II+(IV). My question is, what’s the number in parenthesis mean? I was assuming that this is the rapid class in high water?
Rivers do not always fit neatly in to one category. AW is not the only source to list rapids this way. Plenty of guidebooks (old and new) also do it and it can be quite confusing. Personally, I’ve always taken parenthesis to warily mean one of two things, if not both:: A. The overall river itself has a standard normal rating of Class IV, because of other rapid sets upon it with that same designation(but the particular stretch in question is normally “only” a Class I- II, etc.) --Sorry about the parenthesis, couldn’t help myself. OR, B. As you surmised, at "normal’ flow that same particular stretch of water listed is “only” a Class I-to Class 2 rapid set…BUT can swell to a Class IV when at flood. I don’t claim any of this as definitive, just my experience. So perhaps someone from AW will come along to clarify things? -One thing we can be certain of, is that somewhere at sometime on that same river, we will definitely find a Class IV (Whether we’re prepared for it or not, is another thread entirely ) --Damn, there’s those parenthesis again!!!
A river I paddle near home has a Class III overall rating with AW. But this really only applies to one 8 mile stretch that contains rapids that at “normal” flow are at Class III. (It’s also the most popular stretch with most ww paddlers who frequent it–Oops, darned parenthesis!) .Anyway, my local river itself meanders for a good 40 miles longer with plenty of Cl. I and II rapid sets throughout the rest of it, with no further Class III to be found during “normal” flow conditions. But none of these runs are listed with AW, probably because of not having clearly defined public access when it comes to put-in and take-out. So go figure…
The I-VI system of classification was originally intended to describe individual rapids. But of course, the classification scheme gets applied to whitewater river runs that may include rapids of varying difficulty.
The I-VI classification of individual rapids is often expanded with intermediate classifications. For example, a relatively easy Class Ii might be described as a II- and a harder Class IV might be called a VI+. A rapid that some people call a Class II and some a Class III, or a Class II that quickly morphs into a Class III at slightly higher water levels might be called a Class II-III.
The system breaks down a bit when applied to stretches of rivers rather than individual rapids. What classification do you give a run that is basically straightforward Class II with a single Class IV rapid that many or most people portage? It is not reasonable to simply give such a run a Class IV rating. That is the type of situation in which a Class I-II (IV) rating might be applied.
From AW’s [“Stream Team101” documentation](https://www.americanwhitewater.org/content/Wiki/rivers:sk:instructions “AW “Stream Team101” documentation”):
What about rapid ratings? I mean, what’s “II-III(V)” mean?
In this example, II-III represents the range of most rapids on the river. The V in parentheses means that there are one or two Class-V rapids (which can be portaged). Check out this discussion in the StreamTeam Forum.
AW is also now asking survey participants to submit a decimal point rating next to rapid classifications to get a consensus: Seems plus or minus ain’t cutting it any longer> “Well let me see–I ran it last week at Class IV point 3 and did just fine.
But boy, I really got worked yesterday when it was Class IV point 4!!!”