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Technical Tail-waters: A Play Book

This piece is currently up on the Fulling Mill Blog. This is the unedited/raw version.

Technical Tail Waters: A Play Book

Before the San Juan River was closed due to “the Rona”, I managed to get out on the water for a day of fun fishing with my friend and fellow San Juan River guide, Doug Walker. We had a great day fishing, making fun of each other for missing hooksets, and talking technical trout fishing. With winter at our doorstep and tail waters providing year round fishing opportunities for most trout anglers in the country, I hope these tips will put a few extra fish in your net this coming winter.

Think Trout First

What is trout first? Trout first is thinking about a trout's biological proclivities before you even begin to rig. Tailwaters get a reputation for being hard to fish, but if you think about how trout react to things like temperature, bug activity, and angler pressure it should ease your next day on the water. On tailwaters the two big things I consider when thinking trout first are temperature and angler pressure.

Things to Consider:

Temperature- While fishing in the winter the difference between a few degrees can mean active or sluggish fish. Also, weather trends that positively impact insects will generally make for better trout fishing.

Trout are cold blooded. When the water is colder their metabolic rate slows. You will find them deeper in the water column and in their “winter lies”. Winter lies are generally the slower, deeper runs. Slower, deeper runs are relative to each fishery. If a thick midge or bwo hatch pops off, you can find trout throughout the water column and even pushing up into riffles connected to winter lies. Considering water temperature before you begin fishing can help you locate the most productive water and also make your rigging decisions a little clearer.

Pressure- Tailwaters and heavy angling pressure go together like politics and Thanksgiving. Much like you don’t want to hear your Aunt April talk about shape shifting reptilians from the Draco constellation running the government, you also don’t want to show up to a crowded river but hey, it happens. What do you do about it and how does it impact the trout?

While really pressured trout seem to lose all fear of humans, they make up for it in other areas. Tail water fish become increasingly drift sensitive and in some cases will have very specific feeding windows. This became apparent this past summer when I fished a famous tail water in the A.M. with mixed success; I went back at night to find fish gorging. Because tailwaters can have such a large biomass of small insects, the trout that live there can become size sensitive as well during peak hatch times. While the opposite can also hold true, I generally subscribe to the mantra that pressured fish are more likely to eat smaller bugs. When fishing smaller bugs you’ll also want to fish lighter tippet. A good rule is to divide your hook size by 3. I fish a lot of 6x and even 7x when I’m throwing light midge rigs. I don’t fish light tippet because the fish “can’t see it”, I fish light tippet because it gives you a better drift. In pressured tail waters, drifts matter.

Other Considerations

While not all tailwaters are created equal they generally have a huge biomass of insects. The consistent year-round temperature combined with good year-round flow creates a trout paradise. This is why some tail waters like the San Juan can have trout populations that are estimated around 12k fish a mile. Yes, you read that correctly. Because there is an ever abundant source of food coming right to the trouts’ faces, it means they don’t have to move very far to eat. On many tailwaters, trout will get locked into a band of the water column and stay there for long periods of time. Many times “matching the column” is the most important part of the tail water equation.

(Doug rigging up, note the spacing between the weight and the flies.)

Our Day on the Water

Doug and I met up at the boat ramp at 9am. This was early November in Northern New Mexico and we wanted to let the water bump a couple degrees before we began our day.

The water was still a little cold and the midges hadn’t really started coming off yet. The fish in the Juan are tied to the midge cycle. Blue winged olives are also a major hatch to consider daily. We started with medium weight and went deep to begin. The typical San Juan rig is a tapered 5x leader with about 18-ish inches of 6x blood knotted in. Above the knot is where you crimp your split shot. You tie your first fly to the 6x piece you spliced in and then usually go another 18-ish inches to your second fly. I like to rig eye to eye as it gives you more hook gap because the knot doesn’t block it, especially on the really small stuff.

The morning was filled with laughs and fish as Doug and I both fished the lower parts of the water column. As the day warmed the rigs got lighter and lighter until we were fishing the upper column for trout eating the emerging mayflies and pupating mides. Doug pinned a few up on some dries in the afternoon.I even got out the euro stick and pinned a few. We pretty much kept the same couple bugs on all day with the weight and the distance from the split shot changing frequently from spot to spot.

(Fishing slowed for a minute, but after a quick depth/weight adjustment it was back on)

Putting it all Together

Don’t let tailwaters scare you this winter. Just remember that they’re animals with pea sized brains. If you can think trout first and match the general band of the water column they’re feeding in, you’re going to do great. When in doubt, drop your fly sizes, but I would recommend playing with your weight and indicator-depth-to-weight before getting crazy. More often than not, it’s a good presentation that gets the job done. It's better to fish the “wrong” bugs in the right way. 2020 has been an absolute dumpster fire; spending a day on a tailwater this winter may help you forget, for at least a little bit. Happy fishing.

(Doug with a San Juan Trophy)

To learn more about James or Doug check out their respective guide services or and

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