Tailwater · Mixed · Northern California, US

Lower American River

Lower American River

Cold urban tailwater below Nimbus Dam, running right through Sacramento, which is its own kind of charm — good trout water with traffic noise.

Prime · Rainbow Trout
RS2 · 18-22
Primelive now
About as good as it gets
River high but settled. Coloured water — fish bigger and deeper, confident takes down the seams.
90% confidence
What moved it
  • Level1.93 mLast reading 1h ago
  • Water temp16.6°C
  • ClarityClear
Today's fly
RS2
RS218-22
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
1.93 m
Last reading 1h ago
Water temp16.6°C
ClarityClear
Weather19°C
WindNE 6 km/h
Pressure1019 hPa
Rain · recent0.0 mm
Rain · ahead0.0 mm

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

Water temperature for Rainbow Trout
Ideal
16.6°Cideal 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. Measured at the gauge. 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 insect activity could be better.
Likely species
Chironomids
Gammarids
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 5 active hatches hour by hour as a supporter.

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Sub-surface · on the nymphunder the surface

Hatch predictions

Supporters see the full sub-surface read.

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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.
  • Open all year; barbless, with seasonal/steelhead closures — check CDFW
  • ESA-listed steelhead present: handle with care.
What's coming
Plan ahead
5-day outlook
Other water nearby · 4
South Fork American River
33 km
84
Rainbow trout
Middle Fork American River
38 km
84
Rainbow trout
Lower Mokelumne River
49 km
82
Rainbow trout
North Fork American River
55 km
84
Rainbow trout · Brown trout
Gallery · 2
  1. Lower American River
    The American River flows through Sacramento, California.
  2. Terrain map of the venue
    Terrain map
About this water

Cold urban tailwater below Nimbus Dam, running right through Sacramento, which is its own kind of charm — good trout water with traffic noise. It holds wild rainbows and an ESA-listed steelhead run, so the steelhead get respect and a wide berth. You fish it from a drift boat or on foot with indicators over Baetis and caddis, and in autumn there's egg fishing behind the spawning salmon. The flow and the temperature are both reservoir-managed, so the river answers to the dam, not the weather.

  • Mixed
Conservation note

ESA-listed steelhead are present. We flag them as part of the river and nothing more — no catch score, no targeting nudge. Treat any you encounter as the rare thing they are.

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

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

Recreation: Bacteria/pathogen advisory — mind wading cuts and immersion.

EPA ATTAINS assessment unit 'American River, Lower (Nimbus Dam to confluence with Sacramento River)' (CAR5192100019980813142021), 2024 Integrated Report. Aquatic Life use: Not Supporting. Listed impairment causes: Temperature, Mercury, Toxic Organics, Total Toxics, Pathogens, Polychlorinated Biphenyls PCBs, Pesticides. 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) · CAR5192100019980813142021

The full read · show the working · for Rainbow Trout · confidence 90%
How the 83 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time70 × 13%9.1
Pressure75 × 7%5.3
Insect activity62 × 12%7.4
Conditions total= 83
Can you trust it?
Water temperaturelive gauge readinggauge
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout 1 January → 31 December
Related guides
Euro Nymphingsubsurface methods
Booking & contacts