Big Lost River
BIG LOST RIVER
ReportThe Big Lost River is rounding into good fishing shape as irrigation demands decrease and water storage in Mackay Reservoir begins. Flow below Mackay Dam remains about 300 cfs, which is normal for this time of the season — wade with care. The downstream flow at Leslie is about 220 cfs, making for safer wading.
Tiny BWOs and tricos make up the morning mayfly hatches while midge hatches go on through the day. Terrestrial insects are present in good numbers on vegetated banks.
Flow above Mackay Reservoir is clear and cold, offering much safer wading as well as better dry fly fishing. Terrestrial insect, PMD, trico, and traditional dry fly patterns and hopper-dropper rigs targeting softer water can be effective throughout the day. Try caddis life cycle patterns during evenings.
| Insect | Size | Activity | Prime Time |
|---|---|---|---|
| Blue-Winged Olive (BWO) | #22 | Active | Morning |
| Trico | #22–24 | Active | Morning |
| Midge | #20–24 | Active | All Day |
| Terrestrials (Ants, Hoppers) | #12–16 | Active | Midday |
| PMD | #18–20 | Moderate | Midday (above reservoir) |
| Caddis | #18–20 | Active | Evening |
- MORNING (7–10 AM): Focus on tiny BWO and trico dry fly hatches; fish duns and spinners in the film with a small nymph dropper
- MIDDAY (10 AM–4 PM): Switch to hopper-dropper rigs targeting softer water along vegetated banks, especially above Mackay Reservoir
- EVENING (6–8 PM): Transition to caddis life cycle patterns — pupa and emerger — as caddis activity picks up after sunset
