Rivers are rated by difficulty both based on gradient, volume of water/Flow which is generally in CFS (cubic feet per second), & hazards. The international scale of river difficulty helps you determine how hard a run is, however it should be said that the scale is somewhat exponential in complexity and there is a HUGE variance even between rapids even of the same difficulty designation.
- International Scale of Rivers Difficulty -as stated by Wikipedia
- As judged by swimmer ( I saw this somewhere I will find it and put it up as a link, humourous but also extreemly insightful)
Debate is out there on whether this rating system is perfect I would say that it is imperfect but that it serves as a good basis. You will find debate on whether the type of craft you paddle makes a difference, or if a drop is now run where it previously was not that that should also change the rating. You will also find that folks on one side of the country may have say things like “East Coast Class V = Colorado Class IV
& Colorado Class V = Pacific NW class IV
& PNW Class V = BC Class IV
Then wouldn’t East Coast Class V = BC class II ???” -Water Wacko
So conjecture is out there on what the exact rating should be on any given piece of water. The best advice given when looking at classification is to ask lots of questions & get the beta from the paddling community. Then in deciding whether it is in something you can run, saddle it up next to your skill set, and what you have experience with. This is where judgement becomes a huge part of your skill set which other paddlers around you will value both in keeping yourself safe and helping others make good calls.
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