A scenic Winneshiek County creek near Decorah with healthy populations of both wild browns and rainbows in cold spring water — the name is, once again, a fair description.
- Limestone
Water temperature for Rainbow Trout
Warm — slow22°C est.ideal 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
Today's headline hatch shown — see all 2 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Sub-surface · on the nymphunder the surface
Hatch predictions
See the full sub-surface read with Pro.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey
Hatch predictions
Top prey shown — see all 4 with Pro.
Start free trial14-day free trial. Cancel anytime.
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
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
Rainbow Trout fly box
16-18 · Pattern
Proven pattern for this period
Local fly shops: Driftless Fly Fishing Co.
Permits & access
Permit required — see local rules.
- Iowa DNR — verify regulations.
What's coming
Plan ahead
5-day outlook
Water here around 22°C. Nothing cooler within range — carry a thermometer.
About this water
Water quality · US Clean Water Act
- Aquatic life: Supporting
- Recreation: Impaired
What this classification means
Recreation: Bacteria/pathogen advisory — mind wading cuts and immersion.
EPA ATTAINS assessment unit 'Coldwater Creek' (IA 01-UIA-280), 2024 Integrated Report. Aquatic Life use: Fully Supporting. Listed impairment causes: Pathogens. 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) · IA 01-UIA-280
The full read · show the working · for Rainbow Trout · confidence 90%
How the 15 is built — score × weight = contribution
Temperature9 × 28%2.5
Flow60 × 22%13.2
Clarity85 × 18%15.3
Feeding Time40 × 13%5.2
Pressure75 × 7%5.3
Insect activity56 × 12%6.7
Limiting factor: Water temperature (22.2°C) is outside Rainbow Trout's preferred range (10–18°C)= 48
Can you trust it?
Water temperatureair-to-water estimateestimated
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.
The dawn and dusk windows score higher than the midday lull.
Directions
Seasons & zones
- TroutOpen all year → Open all year
Related guides
Booking & contacts
Coldwater Creek
A scenic Winneshiek County creek near Decorah with healthy populations of both wild browns and rainbows in cold spring water — the name is, once again, a fair description.
Water temperature for Rainbow Trout
Warm — slow22°C est.ideal 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
Today's headline hatch shown — see all 2 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Sub-surface · on the nymphunder the surface
Hatch predictions
See the full sub-surface read with Pro.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey
Hatch predictions
Top prey shown — see all 4 with Pro.
Start free trial14-day free trial. Cancel anytime.
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
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
Rainbow Trout fly box
16-18 · Pattern
Proven pattern for this period
Local fly shops: Driftless Fly Fishing Co.
Permits & access
Permit required — see local rules.
- Iowa DNR — verify regulations.
What's coming
Plan ahead
5-day outlook
Water here around 22°C. Nothing cooler within range — carry a thermometer.
About this water
A scenic Winneshiek County creek near Decorah with healthy populations of both wild browns and rainbows in cold spring water — the name is, once again, a fair description.
- Limestone
Water quality · US Clean Water Act
- Aquatic life: Supporting
- Recreation: Impaired
What this classification means
Recreation: Bacteria/pathogen advisory — mind wading cuts and immersion.
EPA ATTAINS assessment unit 'Coldwater Creek' (IA 01-UIA-280), 2024 Integrated Report. Aquatic Life use: Fully Supporting. Listed impairment causes: Pathogens. 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) · IA 01-UIA-280
The full read · show the working · for Rainbow Trout · confidence 90%
How the 15 is built — score × weight = contribution
Temperature9 × 28%2.5
Flow60 × 22%13.2
Clarity85 × 18%15.3
Feeding Time40 × 13%5.2
Pressure75 × 7%5.3
Insect activity56 × 12%6.7
Limiting factor: Water temperature (22.2°C) is outside Rainbow Trout's preferred range (10–18°C)= 48
Can you trust it?
Water temperatureair-to-water estimateestimated
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.
The dawn and dusk windows score higher than the midday lull.
Directions
Seasons & zones
- TroutOpen all year → Open all year
Related guides
Booking & contacts