Thinking about this some more and continuing the discussion.

Another common use of hyphenated ratings is to indicate a difficulty in between two levels.

ie, When someone says a river is a II-III, they mean "more difficult then II, but not as difficult as III".

This is in conflict with what we've done on the AW site where the range indicates what types
of rapids to expect. eg, a II-IV might be just as difficult as a IV, but it also has rapids that are less difficult.

(I'll also ask that if go with the range usage indicating intermediate difficulty between two levels, then does it also overlap the plus and minus ratings? ie, how is a III-IV different from a III+ or a IV- ?)

/Skip

And perhaps trying to conclude this topic.

Here's my attempt on a formal definition on how to use difficulty ranges on the AW site. I presume something like this could be included in the streamkeeper instructions, or even as a pop-up next to the pull-down menu.

/Skip
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Suggested text of River Difficulty Definition:

River difficulty is listed in the form:
"General-river-character-difficulty (Out-of-character-rapid-difficulty)"

General River Difficulty

The general difficulty may be a single number or a range representing a variety of difficulty levels. (eg, "III" or "II-IV".) Difficulty numbers can be specified as low as class one 'I', or high as class five-plus 'V+' (A "V+" represents any and all difficulty levels greater then class 5.0.)

The general difficulty should be determined by encompassing the difficulty range of of a majority of the rapids on the river *exclusive of out-of-character rapids*. (Majority could be based either upon number of rapids or length of rapids.)

eg, A river has: 6 class III's, 7 class IV's, it would normally be defined as a "IV". But a river with 3 class II's, 4 class III's and 6 class IV's would be a "III-IV". And a river with 4 class II's, 2 class III's, and 4 class IV's would be a "II-IV". (This is somewhat a subjective definition. It will change for each river; a lot depends upon rapid length, consequences of a swim, remoteness of the river, difficulty of rescue, and other factors as well. When deciding the general difficulty it might help to answer the question "what sort of experience will the paddler have on this river?")

When expressed as a range the second number (or when expressed as a single number), the difficulty may also have a minus or a plus attached signifying a slightly easier or more difficult river (eg, III¯, IV+, II-III+, etc.).

This general difficulty level should represent what the paddler encounters at the 'usual, customary, standard' flow. In cases where the difficulty level varies greatly with flow then separate difficulty levels should be specified for different flow levels.

Out-Of-Character Rapids

Parenthetical values listed after general difficulty represent the case for 'out-of-character' rapids. (eg, One or two rapids or areas which, at 'normal, usual, standard flow', are significantly more difficult or dangerous than the rest of the run, *and* can be portaged, lined, or otherwise avoided.) This value will represent the rating of the 'most difficult' of all of the out-of-character rapids. (ie, If a river is a II-III, and contains two other rapids (a IV+, and a V), both of which can be portaged, then the complete difficulty rating would be 'II-III (V)'.

The intent here, is to warn the paddler that these rapids exist, but at the same time they have the option of running or not running them. And that these particular rapids are not indicitive of the character of the run as a whole.
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Here's the complete list (generated by script) that would match the above definition:

I, I(II¯), I(II), I(II+), I(III¯), I(III), I(III+), I(IV¯), I(IV), I(IV+), I(V¯), I(V), I(V+), I–II¯, I–II¯(II+), I–II¯(III¯), I–II¯(III), I–II¯(III+), I–II¯(IV¯), I–II¯(IV), I–II¯(IV+), I–II¯(V¯), I–II¯(V), I–II¯(V+), I–II, I–II(III¯), I–II(III), I–II(III+), I–II(IV¯), I–II(IV), I–II(IV+), I–II(V¯), I–II(V), I–II(V+), I–II+, I–II+(III¯), I–II+(III), I–II+(III+), I–II+(IV¯), I–II+(IV), I–II+(IV+), I–II+(V¯), I–II+(V), I–II+(V+), I–III¯, I–III¯(III+), I–III¯(IV¯), I–III¯(IV), I–III¯(IV+), I–III¯(V¯), I–III¯(V), I–III¯(V+), I–III, I–III(IV¯), I–III(IV), I–III(IV+), I–III(V¯), I–III(V), I–III(V+), I–III+, I–III+(IV¯), I–III+(IV), I–III+(IV+), I–III+(V¯), I–III+(V), I–III+(V+), I–IV¯, I–IV¯(IV+), I–IV¯(V¯), I–IV¯(V), I–IV¯(V+), I–IV, I–IV(V¯), I–IV(V), I–IV(V+), I–IV+, I–IV+(V¯), I–IV+(V), I–IV+(V+), I–V¯, I–V¯(V+), I–V, I–V+, II¯, II¯(III¯), II¯(III), II¯(III+), II¯(IV¯), II¯(IV), II¯(IV+), II¯(V¯), II¯(V), II¯(V+), II, II(III¯), II(III), II(III+), II(IV¯), II(IV), II(IV+), II(V¯), II(V), II(V+), II–III¯, II–III¯(III+), II–III¯(IV¯), II–III¯(IV), II–III¯(IV+), II–III¯(V¯), II–III¯(V), II–III¯(V+), II–III, II–III(IV¯), II–III(IV), II–III(IV+), II–III(V¯), II–III(V), II–III(V+), II–III+, II–III+(IV¯), II–III+(IV), II–III+(IV+), II–III+(V¯), II–III+(V), II–III+(V+), II–IV¯, II–IV¯(IV+), II–IV¯(V¯), II–IV¯(V), II–IV¯(V+), II–IV, II–IV(V¯), II–IV(V), II–IV(V+), II–IV+, II–IV+(V¯), II–IV+(V), II–IV+(V+), II–V¯, II–V¯(V+), II–V, II–V+, II+, II+(III¯), II+(III), II+(III+), II+(IV¯), II+(IV), II+(IV+), II+(V¯), II+(V), II+(V+), III¯, III¯(IV¯), III¯(IV), III¯(IV+), III¯(V¯), III¯(V), III¯(V+), III, III(IV¯), III(IV), III(IV+), III(V¯), III(V), III(V+), III–IV¯, III–IV¯(IV+), III–IV¯(V¯), III–IV¯(V), III–IV¯(V+), III–IV, III–IV(V¯), III–IV(V), III–IV(V+), III–IV+, III–IV+(V¯), III–IV+(V), III–IV+(V+), III–V¯, III–V¯(V+), III–V, III–V+, III+, III+(IV¯), III+(IV), III+(IV+), III+(V¯), III+(V), III+(V+), IV¯, IV¯(V¯), IV¯(V), IV¯(V+), IV, IV(V¯), IV(V), IV(V+), IV–V¯, IV–V¯(V+), IV–V, IV–V+, IV+, IV+(V¯), IV+(V), IV+(V+), V¯, V, V+

Overall, I think that which Skip has proposed is quite good. However, some of the examples seem more confusing than clarifying, and thereby seem better left out. Thus, my comments follow, with the 'format' being:
strike-thru text means suggested deletions,
Green text means suggested additions or corrections.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
River difficulty is listed in the format: "General-river-character-difficulty (Out-of-character-rapid-difficulty)"

General River Difficulty

The general difficulty may be a single number or a range representing a variety of difficulty levels. (eg, "III" or "II-IV".) When expressed as a range, the second number (or when expressed as a single number), The difficulty may also have a minus or a plus attached signifying a slightly easier or more difficult river (eg, III¯, IV+, II-III+, etc.). (Use of minus or plus will be limited to either single difficulty values or to the second value of a range, due to the fact that it confuses and complicates matters if allowed on the first value of a range.) Difficulty numbers can be specified as low as class one 'I', or high as class five-plus 'V+' (A "V+" represents any and all difficulty levels greater then class 5.0.)

The general difficulty should be determined by encompassing characterize the difficulty range of of a majority of the rapids on the river *exclusive of out-of-character rapids*. (Majority could be based either upon number of rapids or length of rapids.)

eg, A river has: 6 class III's, 7 class IV's, it would normally be defined as a "IV". But a river with 3 class II's, 4 class III's and 6 class IV's would be a "III-IV". And a river with 4 class II's, 2 class III's, and 4 class IV's would be a "II-IV". (This is somewhat a subjective definition. It will change for each river; a lot depends upon rapid length, consequences of a swim, remoteness of the river, difficulty of rescue, and other factors as well. When deciding the general difficulty it might help to answer the question "what sort of experience will the paddler have on this river?"

This general difficulty level should represent what the paddler encounters at the 'usual, customary, standard' flow. In cases where the overall difficulty level varies greatly with flow then separate difficulty levels should be specified for different flow levels by specifying ranges on the 'flow info' tab.

Out-Of-Character Rapids

Parenthetical values listed after general difficulty represent the case for 'out-of-character' rapids. (eg, One or two rapids or areas which, at 'normal, usual, standard flow', are significantly more difficult or dangerous than the rest of the run, *and* can be portaged, lined, or otherwise avoided.) This value will represent the rating of the 'most difficult' of all of the out-of-character rapids. (ie, If a river is a II-III, and contains two other rapids (a IV+, and a V), both of which can be portaged, then the complete difficulty rating would be 'II-III (V)'.

The intent here, is to warn the paddler that these rapids exist, but at the same time they have the option of running or not running them. And that these particular rapids are not indicative of the character of the run as a whole. If, for whatever reason, the rapids cannot reasonably be portaged, they should be reflected in the top end of the difficulty range, rather than as a parenthetical 'out-of-character' value.

Rob Smage
AW member since 1992, volunteer since 2000, Midwest Regional StreamTeam Leader

Rob,

Thanks for the great editing job. I agree with almost everything.

The only furthur change I'd make is:

(Use of minus or plus will be limited to either single difficulty values or to the second value of a range, due to the fact that it confuses and complicates matters if allowed on the first value of a range.)

change to:

(Use of minus or plus will be limited to either single difficulty values or to the second value of a range.)

You're right, it can complicate matters. But I was thinking that the first number in a range is primarily of use as an enjoyability measure. (ie, how low does it go); and is less important. The second number in the range is important for safety reasons and therefore needs to be more precise.

/Skip

Write it up as a ticket, and at some point we will get it out.



Ryan