Tailwater · Mixed · Southern California, US

Piru Creek — below Pyramid Dam (catch-and-release)

Piru Creek below Pyramid Dam is Los Angeles' only real tailwater trout fishery, an hour up I-5 at Frenchmans Flat.

Prime · Rainbow Trout
RS2 · 18–22
Primelive now
About as good as it gets
Low and clear — careful approach country. Take your time — read the water before you cast.
90% confidence
What moved it
  • LevelDry recentlyNo gauge reading
  • Water temp11.2°C
  • ClarityClear
Today's fly
RS2
RS218–22
High-confidence seasonal pick
Conditions on the water
Estimate
Level
Dry recently
No gauge reading
Water temp11.2°C
ClarityClear
Weather21°C
WindS 11 km/h
Pressure1014 hPa
Rain · recent0.0 mm
Rain · ahead2.6 mm

No gauge on this water — readings are regional estimates from weather, not a live gauge.

Water temperature for Rainbow Trout
Ideal
11°C est.ideal 10–18°C
0°14°28°

A dam sets this river's temperature, not the weather, so it can shift several degrees within hours when the release changes. It also warms as it runs away from the dam.

How to fish it · for Rainbow Trout
When
Nymphing can work through most of the day.
Where
Cover mixed depths.
Method
Start with tight-line nymphs and adjust if fish rise or drift higher.
Kit
9 ft #4 rod, floating line, 12 ft tapered leader to 4–5 lb fluoro tippet.
Why this works
Excellent — water temperature is right today, though time of day could be better.
Likely species
Mayflies
Caddisflies
Blackflies
  • Blackfly larvae/pupaeMost likelyLower confidence
    #16–18–20 · Pupa
    Small dark soft-hackle drifted through riffle seams.
Chironomids
Aquatic beetles
Molluscs
  • Pond snailsMost likelyLower confidence
    #10–12–14 · Adult
    Dead-drift or twitch a snail pattern near weed beds.
Oligochaetes
  • Aquatic wormsMost likelyLower confidence
    #12–14–16 · Adult
    Dead-drift a worm pattern deep - a year-round staple.
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 8 active hatches hour by hour as a supporter.

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Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 4 guilds as a supporter.

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Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 3 as a supporter.

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Evidence
Records-basedModerate confidence

Based on species-occurrence records, not local invertebrate surveys.

Through the year
0–3 scale · October highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
2
2
2
2
2
1
Western Blue-Winged OliveHatch
2
3
3
3
3
3
3
3
2
Pale Morning DunHatch
2
3
3
2
TricoHatch
2
3
2
Black MidgeHatch
2
3
3
3
3
3
3
3
3
3
3
2

Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.

Ranked for today
Rainbow Trout fly box
Permits & access
Permit required — see local rules.
  • All year, barbless artificial lures, 0 trout, from the bridge below Pyramid Lake to the falls above the old Highway 99 bridge
  • Dam to that bridge: closed to all fishing
  • California licence.
What's coming
Plan ahead
5-day outlook
About this water

Piru Creek below Pyramid Dam is Los Angeles' only real tailwater trout fishery, an hour up I-5 at Frenchmans Flat. Below a short closed stretch under the dam, the creek runs as a small tailwater through a dry chaparral canyon, its flow set by State Water Project releases from Pyramid Lake. From the bridge below the lake down to the falls above the old Highway 99 bridge it's barbless artificials only and every trout goes back. The canyon gets hot in summer and releases change without a public schedule, so go early and go light.

  • Mixed
Conservation note

Rainbow trout, released. Whether they are wild or holdover hatchery fish is not established by CDFW; brown trout are not confirmed here and are not listed.

The full read · show the working · for Rainbow Trout · confidence 90%
How the 84 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time60 × 13%7.8
Pressure75 × 7%5.3
Insect activity80 × 12%9.6
Conditions total= 84
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
The dawn and dusk windows score higher than the midday lull.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout 1 January → 31 December
Related guides
Euro Nymphingsubsurface methods
Booking & contacts