How To Fly Fish In Moving Water

Fly fishing in rivers is a favourite pastime for many anglers. The flowing water and varying depths make for an exciting and challenging fishing experience. When it comes to fly fishing in rivers, there are a few techniques that every angler should have in their skill set. This blog will cover the top techniques for fly fishing in rivers, the gear you need, and tips for beginners.

Understanding the Dynamics of Fast Moving Water

To fish successfully in rivers, it's crucial to know how fast-moving water works. Understanding the water flow helps you know where the fish are and how to catch them with your fly.

The Science Behind Water Flow and Fish Behavior

Moving water creates a lot of force. The speed of the water in a river is determined by two factors.

The first factor is the steepness of the riverbed. The second factor is the amount of water that comes from rain, snow, and melting glaciers in the watershed. The steeper the slope, the faster the water will flow. More water entering the watershed will result in higher water depths and increased force.

When a river has a steep gradient, it will also be more turbulent, with lots of rocks and boulders creating rapids and eddies. Conversely, a river with a shallow gradient will flow slower and is less likely to contain rapid sections. Typically the higher you go up river the steeper the gradient will be and the lower you get on a river system the lower the gradient will be.

While there are many different classifications of river sections the two most basic are freestone sections which are higher in the river system and have a higher gradient as well as more turbulent waters and tailwater sections which are located lower on the river and have less gradient and typically less turbulence. Many of today's tailwater sections can be located easily as they exist in many cases below dams.  

Essential Gear for Fly Fishing in Fast Water

When it comes to fly fishing in rivers, you’ll need to make sure that you have the right gear. The flowing water and rocky riverbed can make for a challenging fishing environment. Not only will you need to navigate the river, but you’ll also need to make sure that you can get your fly in front of the fish. Here’s a look at some of the essential gear you’ll need for fly fishing in rivers.

Choosing the Right Rod and Reel

The first step to fly fishing in rivers for trout is making sure that you have the right rod and reel. We recommend using a 9-foot rod with a weight of either 5, 6 or 7 depending on the technique you are using. A 5wt rod is perfect for nymphing and casting dries.

We typically use 7wt rods to cast streamers and foam / dry dropper rigs. A 6wt rod is a great choice for a “do it all rod” and can be very versatile on the river while not particularly accelerating in any particular technique. A 9-foot rod will give you the length that you need to cast your line out, while certain styles of nymphing such as tight lining and euro nymphing can require longer rods from 11’ to 13’

Waders and Boots: Ensuring Safety and Comfort

Waders and wading boots are a must-have for fly fishing in rivers. Adjacent tree lines, banks and brush can make it very difficult to fish from the riverbank plus in many cases, you may need to cross the river to get into the best position to fish the pool or run.

To fly fish in rivers, you’ll likely need to wade out into the water often.

It is recommended to wear waders and boots while fishing in cold water during the spring and fall seasons. This is better than wearing just sandals and shorts. Waders and boots will keep you warm and dry.

Sandals and shorts may not provide enough protection from the cold water. In addition, if the river banks are overgrown with brush or you are fishing in freestone sections then navigating the river bed in shorts and sandals can lead to lots of cuts, scratches and discomfort.

Choosing the Right Fly

Once you have the right gear, the next step is to master the art of fly selection. The flies that you choose to fish with can have a huge impact on your success.

In general, when it comes to fly fishing in rivers, you’ll use a dry fly, nymph or streamer. Dry flies are flies that float on the surface of the water, while nymphs are flies that sink below the surface of the water. Streamers are fished typically shallow below the surface from 6” to 2’. 

What Flies to Use in Fast Moving Rivers

There are endless varieties of flies that you can use to fly fish in rivers. At its most basic there are three different kinds of flies.

Naturals imitate a specific natural bug that is present in a river system. Searching patterns which work in many river systems and generally do a great job of imitating multiple bugs and Attractor patterns which are meant to grab attention and typically drive a predatory response.

Some of our favourite nymph patterns include the Pheasant Tail Nymph, the Copper John, and the BWO. In fast moving rivers, it can be an advantage to use a heavy nymph, like a stonefly.

Heavy nymphs are great for fast moving rivers because they can sink down deep and get your fly in front of the fish. In many cases we also use a drop rig setup that has an additional split shot for weight on the bottom to really help get your nymphs down!

Dry flies can be very seasonal and it’s best to check with the local fly shop where you are fishing for details on current hatches. Some of our favorite searching patterns for dry flies are the Adams, Purple Haze and Chernobyl Ants.

Streamer patterns can be a great choice when fishing in fast heavy water. There are two basic types of streamers, single hook streamers and articulated streamers. Most articulated patterns have two hooks while others have single hooks and a spine so make sure to check your local regulations to ensure that you can use two hooks at the same time when fishing articulated streamers. Some of our favorite streamer patterns include Galloup's Dungeon, The Circus Peanut and the Autumn Splendor.   

Fly Size and Color: Making the Right Choice

When fishing natural patterns It’s not only the type of fly that matters, but also the size and color of the fly. You’ll want to use a fly that is appropriate to the size of the natural bugs in the river system. You’ll also want to make sure that your fly is the right colour.

In general, when fishing with naturals it’s best to use a fly that is the same color as the insects that are in the river. To check that your selection is correct, flip over some rocks or use a bug seine to catch some river bugs and compare your flies to the naturals that are present and pick the closest matching patterns you have in your fly box. 

How to Fly Fish Fast Moving Water

Now that you have the right gear and you’ve mastered the art of fly selection, it’s time to get out on the river. Fly fishing in rivers requires skill and technique. The flowing water and varying depths as well as the fish's temperament and selectiveness make for a challenging fishing environment. Here are some tips for fly fishing in rivers.

Casting Strategies for High Water Speeds

Casting in fast moving water can be challenging. The speed of the water can make it difficult to place as well as drift or swim your fly where you want it to.

When it comes to casting in fast moving water, less is more. You’ll want to make shorter, more controlled casts. Here are a few casting strategies to try:

1. Over hand casting: This technique is common and is used anytime you have the room behind you to cast and is the most basic casting type. 

2. Single-Handed Spey Casting: Spey casting is a casting technique that is commonly used in rivers. Spey casts are great for making long casts in tight quarters. If you’re fishing in a river with a steep bank, try using a single-handed spey cast to get your fly out into the water.
3. Roll Casts: Roll casts are another great casting technique for fly fishing in rivers. Roll casts are a type of cast that is used to cast your line out in front of you. They’re great for fishing in rivers because they allow you to cast your line out without casting it behind you.

Reading the River: Identifying Promising Spots

One of the most important skills for fly fishing in rivers is being able to read the river. By understanding how the water is flowing, you can better understand where the fish will be. Here are some tips for reading the river.

1. Look for Eddies: Eddies are a great spot to find fish in fast moving water. An eddy is a spot in the river where the water is flowing in the opposite direction. In fast moving water, fish will often seek refuge in eddies.

Eddies are a great spot to find fish because the swirling water will carry insects to them. When fly fishing in rivers, make sure to cast your fly into eddies.

2. Fish the Seams: The seam is the line where two different currents meet. In fast moving water, the seam is a great spot to find fish. Fish will often position themselves in the seam, where they can easily move between the two currents. When fly fishing in rivers, make sure to cast your fly into the seam.

Positioning Yourself and Getting A Good Drift: Getting Your Fly In Front Of Fish

Now we are ready to cast our fly and catch a drift! In fast-moving water, this can be challenging. Here are some tips for getting a good presentation and drift in fast-moving water.

1. Positioning: There are a lot of ways to position yourself as a fly angler to present to fish. The two most basic positions are to cast out 90 degrees to or from a bank and the second is to cast upstream from a downstream position.

Casting 90 degrees will typically require more mending for dry flies and nymphs while it is a pretty standard position for throwing streamers. Casting upstream can give the element of surprise and generally requires less mending for both dries and nymphs and is used less in streamer fishing.

2. Mending Your Line: Mending your line is a technique that is used to reposition your fly in the water. In fast-moving water, it’s likely that your fly will get swept up in the current. By mending your line, you can reposition your fly line and create a natural drift. You always want to keep your line from pulling on your fly, this ensures that the fly is drifting at the same speed as the water it is sitting in.

When it comes to streamers you will retrieve your fly by pulling on your main line so obviously you will be pulling it through the flowing water. In this case, mend your line so that your streamer isn't swept down the river and swims perpendicular to the river current. 

3. High Sticking: High sticking is a fly fishing technique that is commonly used in rivers for both dry flies and nymphing. High sticking is a technique that is used to keep your line out of the water and out of currents that are at different speeds than the water your fly is in.

By keeping your line as high as you can and out of the water, you can maintain better control over your fly sometimes without having to mend it. In fast-moving water, high sticking can be a great way to keep your fly moving naturally.

How to Deal with the Challenges of River Fishing

Fly fishing in rivers comes with its own set of challenges. The fast-moving water and varying depths can make it difficult to get your fly in front of the fish. Here are some tips for dealing with the challenges of river fishing.

1. Dealing with Wind: The wind can make fly fishing in rivers challenging. The speed of the water can cause your line to get caught in the current.

When fly fishing in rivers on a windy day, try using a heavier fly or heavier-weight rod. Heavier rigs are less likely to get caught in the wind.

You can also try using a shorter leader line. By using a shorter line, you can maintain better control over your fly.

2. Dealing with Muddy Water: After a rainstorm, the water in the river can become muddy. Muddy water can make it difficult for fish to see your fly. When fly fishing in rivers with muddy water, try using a darker fly, dark flies can stand out well when low visibility conditions are present. 
3. Wading in heavy fast water: Always be cautious when wading in moving water. Too heavy a flow, slippery rocks and soft bottoms can all cause you to fall while wading and be swept down river in the current.

When making a crossing always go slow and ensure your footing is solid before you make another step. If you feel that the current is getting too strong, never move forward, always head back to shore. Whenever possible, set up your crossing so that you are moving slightly downstream. Crossing with a buddy is a great option locking arms and working together can make heavy water crossings a lot easier.

A wading staff can be a great tool to help you balance as you cross and check out riverbed conditions before you make your next step.

Don't cross the river near dangerous areas like ledges or rapids. Avoid crossing the river near dangerous areas such as ledges or rapids.

Make sure to give yourself enough space in case of an emergency. This way, you can safely return to shore before getting swept into danger.

If you're not sure or comfortable, don't cross the river. It's better to be cautious and safe. Don't take risks, even if the other side looks tempting.

At Rocky Mountain Fly Shop, we’re passionate about fly fishing. Our blog dedicates itself to providing anglers with tips, tricks, and valuable information about the sport we love. For all your fly fishing gear needs, check out our selection at Rocky Mountain Fly Shop online today, and be sure to stay tuned to our blog for more insightful content!