Just like there are specialized terms for the places we drive, there also specialized terms for the rivers we travel. These terms are used to describe features, hazards, and more. When you sign up for a whitewater rafting trip with Killgore Adventures, you’re likely to hear your Idaho river outfitters use some of these terms. If you’re a “know before you go” type, you’ll appreciate knowing about these river terms.

The Flow

Here in the U.S., we measure our rivers in volumes of cubic feet per second. When your raft guide talks about the rivers flow they’re talking about the condition of the river itself. To determine the cubic feet per second, your river guide might use a simple formula: river width x river depth x speed = cubic feet per second. Generally speaking, the higher the CFS the more water is moving in that particular part of the river.

High and Low Water

Depending on the season and the snowpack that year the river may have high or low water. High and low water river conditions can have an impact on your white water rafting trip. Just because the water is higher doesn’t mean that the river will be calmer. In some cases, higher water might reveal new rapids and new challenges. Similarly, low water can reveal more rapids and obstacles. In fact, different parts of the river can have different heights of water. Some parts might be higher while others are lower. Ultimately, this adds a dynamic element to your whitewater trip.


This is what you’re here for. Rapids are the fun and exciting part of your whitewater trip. Rapids are formed when parts of the river are constricted or the riverbed changes in some way. But not all rapids are made equally. Rapids have varying degrees of difficulty from class 1 to class 6. Basically, class 1 rapids are just slow-moving flat water. Class 6 rapids, on the other hand, are sections of a river that have never been attempted by whitewater rafters or kayakers and are extremely difficult, unpredictable, and even dangerous. Rapids can be short and fierce or long and predictable. It really depends on the time of the season and which section of the Salmon or Snake Rivers you’re floating down.

Put-In and Take-Out

The put-in is the area in which we start our river rafting adventure. This is where we will first put our boats in the water, put our gear on, and start our trip. The take-out is the final point of our rafting trip. From here we’ll remove our boats from the water, collect all of our safety gear, and load back into the buses to head home.

River Left and River Right

No matter which way you’re facing, river right and river left will always be in the same direction. As you’re heading down river, river right is on your right-hand side and river left on your left-hand side. However, should you be facing upstream these sides will be reversed. River right will be on your left-hand side while River left will be on your right-hand side. This may sound confusing but will come to you naturally with just a little bit of practice.

A Rock Garden

As you travel you may notice several sections of the river where there are large patches of boulders sticking out of the water. Your Idaho river outfitter may refer to these as rock gardens or boulder gardens. In some cases, you may be able to float over or through these rock gardens. But often, your river guide will direct you around the boulders in those cases.

An Eddy

Eddies are features that form downstream of an obstruction. For instance, large stones off he often have eddies behind them. Eddies are a portion of the river that is flowing in the opposite direction of the rest of the river, meaning that they swirl around. In many cases, eddies can be used to slow your advance down the river or even stop you entirely. However, in other cases, the eddies may be too powerful and can even cause your raft to roll over. The transition between the mainstream of the river and the eddy is called the eddy fence.

The Green Tongue

As you move towards a section of rapids you may notice a triangular section of the river that leads into the rapids. This is called “The Green Tongue” by many raft guides. It is the last portion of flatwater you’ll experience until you move through the rapids.

A Hydraulic or Hole

A hydraulic or hole forms when the river moves over the top of a rock, ledge, or other obstacles in the river. As the river moves over this obstacle the water current moves toward the bottom of the river and reverses back onto itself. In some cases, large and powerful hydraulics can actually flip a raft. However, smaller hydraulics can be “surfed” and can be a lot of fun to travel on.

Take a Whitewater Rafting Trip Through Hells Canyon Today

Ready to try white water rafting for yourself? Then Killgore Adventures has just the trip for you.  We offer whitewater rafting trips that last as little as a single afternoon or can stretch up to three days long. It’s a great way to explore some of the most amazing sections of the Salmon and Snake Rivers in Idaho. Connect with the experienced river outfitters at Killgore Adventures, Idaho’s #1 adventure company today to book your trip.