Tailwater · Mixed · Northern California

Lower Stanislaus River

Lower Stanislaus River terrain map

Cold foothill tailwater below Goodwin Dam, which is itself a regulating afterbay for big New Melones up the canyon — so the flow you get at Knights Ferry is whatever the Bureau decides, not what the sky does.

Poor · Rainbow Trout
Sparkle Dun · 14-18
Poorlive now
Not the day for it
River high but settled. Not much stacked in your favour today. Worth an hour if you are nearby, not worth the special trip.
90% confidence
What moved it
  • Level11.73 mLast reading 7h ago
  • Water temp22.2°C
  • ClarityClear
Today's fly
SD
Sparkle Dun14-18
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
11.73 m
Last reading 7h ago
Water temp22.2°C
ClarityClear
Weather27°C
WindNW 17 km/h
Pressure1015 hPa
Rain · recent0.0 mm
Rain · ahead0.0 mm

Live readings only. Trends shown where the gauge supports them.

Water temperature for Rainbow Trout
Warm — slow
22.2°Cideal 10–18°C
0°14°28°
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
Water at 22.2°C. This is the line where catch-and-release kills brown trout. Do not fish for them today.
Hatch timeline · todayQuiet day

Hatch predictions

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Sub-surface · on the nymphunder the surface

Hatch predictions

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Beyond the hatch · worth watchingambient prey

Hatch predictions

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Evidence
ModelledModerate confidence

Modelled from regional ecology — no survey or occurrence data for this water yet.

Through the year
0–3 scale · July 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.
  • Open all year; barbless, with low-flow / steelhead closures — check CDFW
  • ESA-listed steelhead present: handle with care
  • Flow tracks Goodwin/New Melones releases.
What's coming
Plan ahead
5-day outlook
Water here at 22.2°C. Nothing cooler within range.
About this water

Cold foothill tailwater below Goodwin Dam, which is itself a regulating afterbay for big New Melones up the canyon — so the flow you get at Knights Ferry is whatever the Bureau decides, not what the sky does. It holds wild rainbows along with an ESA-listed steelhead run, so those fish get named and left alone. Drift-boat and walk-in water over clean gravel: caddis and PMD through the warm months, blue-wings when it cools, and an egg bite behind the autumn salmon. Check the release before you load the boat, because the river answers to the dam.

  • Mixed
Conservation note

Holds ESA-listed Central Valley steelhead. We name their presence and leave it there — no catch score on listed fish, no targeting nudge. Handle any you meet with real care.

Water quality · US Clean Water Act
  • Aquatic life: Impaired
  • Fish consumption: Impaired
What this classification means

Fish consumption: Consumption advisory (Mercury) — fish for sport, not the table.

EPA ATTAINS assessment unit 'Stanislaus River, Lower' (CAR5353000019980817151834), 2024 Integrated Report. Aquatic Life use: Not Supporting. Listed impairment causes: Temperature, Mercury. This is a Clean Water Act assessment-unit classification (the US analogue of WFD), not a live reading.

Status is for the Clean Water Act assessment unit covering this reach.

EPA ATTAINS (Clean Water Act) · CAR5353000019980817151834

The full read · show the working · for Rainbow Trout · confidence 90%
How the 15 is built — score × weight = contribution
Temperature9 × 28%2.5
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time85 × 13%11.1
Pressure75 × 7%5.3
Insect activity63 × 12%7.6
Limiting factor: Water temperature (22.2°C) is outside Rainbow Trout's preferred range (10–18°C)= 59
Can you trust it?
Water temperaturelive gauge readinggauge
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
Cooler water — back toward the 10–18 °C ideal band — would lift the score and ease welfare.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout1 January → 31 December
Related guides
Euro Nymphingsubsurface methods
Booking & contacts