Spring Creek · Limestone · Wisconsin, US

Big Green River

Big Green River terrain map

Among the most prized of southern Wisconsin's Class I streams, a fertile Grant County limestoner with good public access and a deserved name for both numbers and the odd outsized brown.

Tomorrow · A proper day on the water
Scud
Forecast · Tomorrow
A proper day on the water
A proper day for it. Work the seams with an upstream nymph, switch to the dry when they show.
75% projected
Today's fly
Scud
Scud
Conditions on the water · Tomorrow
Proxy gauge
Level
Steady
Proxy
via Bloody Run Creek
Water temp17.9°C
ClarityClear
Weather26°C
WindN 11 km/h
Pressure1013 hPa
Rain · recent0.1 mm
Rain · ahead9.8 mm

No gauge on this water — conditions are inferred from Bloody Run Creek. The trend transfers, the absolute level does not.

Water temperature for Brown Trout
Warm — slow
18°C est.ideal 10–16°C
0°14°28°
How to fish it · for Brown 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
terrestrials
Hatch timeline · tomorrowPeak at 7am

12pm(now) — Grasshopper (Eastern)

Stage: Terrestrials on topApproach: Dry flyActivity: 84%
Also:Reed Smut59%Trico (Eastern)50%
Peak emergence windowWeather boostEmergence building5 food groups active

Peak activity at 7am — Trico (Eastern) (Trico (Eastern), Weather boost)

Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 3 guilds with Pro.

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Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 4 with Pro.

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Evidence
Records-basedModerate confidence

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

Through the year
0–3 scale · September highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
1
SulphurHatch
2
3
2
Trico (Eastern)Hatch
2
3
3
2
Eastern Blue-Winged OliveHatch
2
3
3
3
3
3
3
3
2
Eastern Summer BWO (Drunella)Hatch
2
3
3
2

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

Ranked for today
Brown Trout fly box
Local fly shops: Driftless Angler
Permits & access
Permit required — see local rules.
  • WI DNR — verify reach regulations.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Castle Rock Creek
12 km
0
Brown trout
Blue River
32 km
0
Brown trout · Rainbow trout
Bloody Run Creek
38 km
Brown trout · Rainbow trout
Tainter Creek
53 km
0
Brown trout · Brook trout
Yellow River
57 km
71
Brown trout · Brook trout
About this water

Among the most prized of southern Wisconsin's Class I streams, a fertile Grant County limestoner with good public access and a deserved name for both numbers and the odd outsized brown. Open meadow stretches mean wind-blown terrestrials matter all summer.

  • Limestone
Water quality · US Clean Water Act
  • Aquatic life: Not assessed
What this classification means

EPA ATTAINS assessment unit 'Little Green River' (WI10002544), 2024 Integrated Report. Aquatic Life use: Not Assessed. 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) · WI10002544

The full read · show the working · for Brown Trout · confidence 90%
How the 83 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time55 × 13%7.2
Pressure80 × 7%5.6
Insect activity64 × 12%7.7
Conditions total= 83
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowproxy via Bloody Run Creekproxy
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 First Saturday in January (early catch-and-release, artificial only) → October 15 (regular harvest season from first Saturday in May)
Related guides
Euro Nymphingsubsurface methods
Booking & contacts