Fly Fishing San Juan River - Below Navajo Dam

Overview

The San Juan immediately below Navajo Dam is a reservoir-fed tailwater in northwestern New Mexico. This upper reach combines deeper runs around Texas Hole with riffles, glassy flats and braided channels farther downstream. The contrast between a deep current lane and a shallow flat makes depth and line control central to the presentation.

Rainbow and brown trout are the focus here. Small midge larvae, pupae and adult patterns offer subsurface and surface choices, while Baetis patterns provide another option when mayflies are active. A small midge nymph beneath a San Juan worm explores the deeper lanes; a tiny dry calls for a careful drift to a visible rise. Streamers offer a different way to work the pools in lower light.

Small flies and controlled drifts

Midge larvae, pupae and adult patterns in sizes 24 to 28 give you different ways to approach the water. Nymphing a small midge larva beneath a San Juan worm is one subsurface option. Choose the current lane first, then adjust the depth so the flies settle before they reach the deeper part of the run.

A flat calls for a different presentation from the pool beside it. Watch for a rise before casting a tiny dry, and keep the leader from dragging across neighboring currents. During a midge cluster hatch, place the fly in the feeding lane rather than covering the whole flat with repeated casts.

Baetis activity in spring and fall adds blue-winged olive patterns to the choices, especially on overcast days. Use the insects and rise form in front of you to choose a smaller dry or emerger. A change in line control may improve the drift more than another pattern change.

Move between runs and flats

Texas Hole provides a deeper run within this upper tailwater. Farther downstream, riffles, glassy flats and braided channels break the water into different features. Work one lane at a time: a nymph presentation in the deeper run may need less depth and a shorter drift in the next channel.

Along a soft edge, keep the flies moving with that current rather than letting the faster water pull them away. In a deeper pool, a streamer offers another presentation. Give it time to settle and vary the retrieve for the current and cover rather than expecting one speed to fit every hole.

Midge and Baetis activity can overlap. Watch which part of the water is drawing rises before switching from a nymph rig to a dry. The same attention to depth, current lane and drag matters whether the cast is into a pool, along a seam or across a glassy flat.