Fly Fishing Tailwaters: It’s Not You, It’s the Trout (Probably)
On a recent trip to Montana, I was reminded of the challenges and rewards that come with fly fishing tailwaters. These fisheries hold both large and numerous trout but often at a price- they’re hard to catch!
Fly fishing tailwaters is a game of picky fish, tiny flies, and often asking yourself, “How can it be so hard to catch a fish in a river that is full of them?”
So, if you’re ready to get technical, tie on microscopic flies, and possibly question all of your life choices, you’ve come to the right place! Let’s dive into the magical (and mildly maddening) world of fly fishing tailwaters.
Key Points for Fishing Tailwaters
Tailwaters are rivers that flow from dams. They’re the perfect homes for trout, providing constant cool water temperatures and abundant food sources.
Tailwater fish are picky- they can be selective on what they want to eat. Typically, you’ll need to use very small flies, natural presentations, and lots of patience and experimentation.
Expect to spend your day adjusting, rethinking your setup, and wondering how trout even see these tiny flies. But when you finally hook one, you’ll feel like a fly fishing genius!
As a starter, check out our Beginner’s Guide to Fly Fishing for Trout.
What is a Tailwater?
A tailwater is a river or stream that flows from a dam. Essentially, you have a large reservoir or lake and when water is released from that body of water, the result is a river or stream known as a tailwater.
When talking about tailwaters and fly fishing, we are usually referring to “bottom draw” tailwaters, which take water from the bottom of a reservoir. This water is cooler and provides the ideal conditions for aquatic bugs and in turn, the ideal homes for trout.
Spillway dams or “top draw” tailwaters are rivers that are created from warmer water at the surface flowing over a dam, which don’t create the same trout-y environment. So when you hear about trout fisheries and tailwaters, it’s most likely a bottom draw system.
Unlike natural freestone rivers, where water flows freely over rocks and through the landscape, tailwaters are highly controlled systems. The water released from the dam is often cooler, more stable, and provides consistent fishing conditions year-round. These environments create perfect habitats for large trout, but they also require a bit more technical skill to fish successfully.
How Do Tailwaters Work?
The key feature of a tailwater is the dam that regulates the water flow. Because the water is drawn from the bottom of the reservoir, it remains cool even in summer, which is ideal for trout. The steady flow means that tailwaters don’t experience the same dramatic changes in water level or temperature that you might find in freestone rivers during snowmelt or after a rainstorm. This stability leads to consistent insect life and an abundance of food for trout.
Tailwaters exist for a variety of reasons outside of angling opportunities. Releasing water from dams provides hydroelectricity that can power the surrounding area. Dams (and the resulting tailwaters) also supply water for irrigation and human consumption. While these are important on a larger scale, let’s get back to the fun stuff- the fishing!
Tailwaters tend to be nutrient-rich, supporting healthy populations of aquatic insects like midges, mayflies, and caddisflies. These insects hatch in predictable patterns, meaning the trout are often well-fed and selective about what they eat. As a result, the fish in these rivers become highly specialized and can be notoriously picky.
Tailwater vs Headwater
While tailwaters are known for their controlled conditions, headwaters are the opposite. Headwaters are the sources of rivers—often high in the mountains—where water flows directly from springs, snowmelt, or small streams. These rivers are typically much less stable than tailwaters, with water levels fluctuating dramatically based on the season, weather, and snowpack.
In headwaters, trout are often opportunistic feeders. Because their environment is less predictable, they have to take whatever food is available at the time. This makes headwater fish more willing to strike a variety of flies, especially larger and more impressionistic patterns.
In contrast, tailwater trout are more selective due to the constant availability of small, specific insects, meaning anglers must pay close attention to fly selection and presentation.
Fly fishing tailwaters is notoriously challenging. Trout get very particular on what they eat simply because they are key in on specific bugs. Tailwaters provide such consistent prey items that trout often get very selective on what they want to eat that day. As a result you get not only very picky fish- but also very large ones.
How to Fly Fish Tailwaters
Fishing tailwaters can be incredibly rewarding, but it requires a more technical approach than many other types of water. Here are some tips to help you have a successful day on a tailwater river:
Use Small Flies
One of the most important rules for fishing tailwaters is to downsize your flies. Because of the consistent insect life, tailwater trout often prefer small, simple patterns. Midges and tiny nymphs are a staple of the diet here, so flies in sizes 18-24 are common. While it’s tempting to fish bigger, flashier patterns, remember that these fish are used to feeding on small insects and can be suspicious of anything larger.
Downsizing can be frustrating in my opinion. When I fish size 20 nymphs, I find myself asking “how in the world can a fish see this??” However, somehow they do and it’s typically the only way to catch fish consistently.
Because we’re fishing such small flies, it’s often necessary to make many casts to the same hole. A difference of 4 inches can make all the difference between a fish seeing your fly and having it drift by. Give your flies several chances to get in front of a fish’s face and soon enough you’ll get bit. Fish each hole very thoroughly and be patient!
Match the Hatch
Tailwater trout are picky, and they often focus on very specific insects. To get hooked up, you’ll need to closely imitate whatever is hatching at the time. Local knowledge can be key- ask fly shops and other anglers what has been working lately.
Imitative patterns, rather than attractor patterns, are key in these situations. The more accurately your fly mimics the natural insects, the better your chances of hooking a fish.
While each fishery is different, you can count on midges, small mayflies, and small caddisflies being on the menu. Key word here is small!
From my experience fly fishing tailwaters, you can’t go wrong with midge patterns. Midges are a common food source for trout in tailwaters and are often abundant.
Zebra Midges are the Wooly Buggers of tailwaters (Wooly Buggers are also the Wooly Buggers of tailwaters). These flies imitate the plentiful species of midges in tailwaters and are a go-to pattern for these fisheries.
Adjust Your Depth
Finding the right depth is crucial when fishing tailwaters. Fish will often hold at different levels in the water column, depending on what they’re feeding on. If you’re nymphing, make sure your flies are getting down deep enough. On some days, adding a small split shot or adjusting your indicator can make all the difference. If fish are targeting emergers, you may need to adjust your rig to present flies higher in the water.
The key word is experimentation. Fly fishing tailwaters takes patience and trial and error. I find myself constantly changing depth, weight, and flies. These finicky fish can be frustrating, but finding the right combination of flies, weight, and depth is the challenge of these fisheries.
Check the Flows
While tailwaters are known for their stability, they can still fluctuate due to dam releases. Always check the flow levels before heading out. High flows can make fishing difficult, while low flows might make the trout more wary. Understanding the river’s flow at any given time will help you adjust your strategy and increase your chances of success.
The amount of water released by the dam is often determined by local needs. If more hydroelectricity is needed to power the area, flows will be higher. If there hasn’t been a ton of rain and water is needed for irrigation, they’ll let more out.
Knowing the exact schedule can also be important for safety. I was once fishing a tailwater in Arkansas and was warned to get out of there by a certain time. Not thinking much of it honestly (and busy fishing), the water levels quickly rose as they released water from the dam to power people’s homes during a cold winter night. A comfortable wade quickly turned into a dash for the shore!
Be Stealthy
Tailwater trout are often heavily pressured by other anglers, which makes them extra cautious. Being discreet in both your rig and your movements can greatly improve your chances. Use smaller indicators, like yarn or a dry-dropper setup, and avoid the large, bright indicators you might use in other waters. Move quietly, minimize false casting, and stay out of sight as much as possible to avoid spooking the fish.
The water in tailwaters is also very often gin-clear. Trout are more aware of their surroundings and are more likely to see anglers who just want to hook them briefly, take a picture, and send them off on their way.
Drab clothing and thin tippets can reduce the chances of trout seeing you and your line. Quiet approaches and limited false casts also increase your likelihood of hooking up. Stealth is paramount when fly fishing tailwaters, so don’t take it for granted!
Conclusion
Tailwater trout aren’t your typical “whatever floats by” kind of fish—they’re the food critics of the river. But once you figure them out, you can have a day to remember. So embrace the challenge, pack your tiniest midges, and don’t forget to check the flow before you wade in—you don’t want to end up sprinting for the shore like I did!
Stay sneaky, experiment with your flies and depth, and enjoy the satisfaction of outsmarting these finicky fish.
Do you like fishing tailwaters?
