Mayflies
Caddisflies
A well-known Allamakee County creek near Dorchester, just over the line from Minnesota, with wild and stocked browns and rainbows in cold limestone water. A Driftless favourite that fishes hard and rewards persistence.
- Limestone
Rules at a glance
- Free fishing
- Fly only
Water temperature for Rainbow Trout
Ideal17°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 20°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Likely species
Mayflies
Caddisflies
- Little Black Caddis (East)Most likelyLower confidenceNearest relative#16–18–20 · Adult
- Green Caddis / Rock WormAlso possibleLower confidence#14 · Adult
- Tan Caddis / Spotted SedgeAlso possibleLower confidenceNearest relative#14–16 · Adult
- October CaddisAlso possibleLower confidenceNearest relative#6–8–10 · Adult
Hatch timeline · tomorrowPeak at 7am
12pm(now) — Grasshopper (Eastern)
Stage: Terrestrials on topApproach: Dry flyActivity: 37%
Also:Trico (Eastern)31%Reed Smut26%
Peak emergence windowWeather boostEmergence building5 food groups active
Peak activity at 7am — Trico (Eastern) (Trico (Eastern), Degree-days at peak)
Sub-surface · on the nymphunder the surface
Hatch predictions
Top nymph shown — see all 4 guilds with Pro.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey(1)
Hatch predictions
Top prey shown — see all 4 with Pro.
Start free trial14-day free trial. Cancel anytime.
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
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
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
Cooler water nearby · 5
Water here at 20.0°C — the fishing's alive, but these are cooler if you'd rather rest the warm water.
Gallery · 1
Terrain map
About this water
Water quality · US Clean Water Act
- Aquatic life: Impaired
- Recreation: Impaired
What this classification means
Recreation: Bacteria/pathogen advisory — mind wading cuts and immersion.
EPA ATTAINS assessment unit 'Waterloo Creek' (IA 01-UIA-253), 2024 Integrated Report. Aquatic Life use: Not Supporting. Listed impairment causes: Pathogens, Cause Unknown Impaired Biota. 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-253
The full read · show the working · for Rainbow Trout · confidence 80%
How the 28 is built — score × weight = contribution
Temperature30 × 28%8.4
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time65 × 13%8.5
Pressure75 × 7%5.3
Insect activity57 × 12%6.8
Conditions total= 62
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.
The dawn and dusk windows score higher than the midday lull.
Directions
Seasons & zones
- Trout Open all year → Open all year
Related guides
Booking & contacts
Waterloo Creek
A well-known Allamakee County creek near Dorchester, just over the line from Minnesota, with wild and stocked browns and rainbows in cold limestone water.
Water temperature for Rainbow Trout
Ideal17°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 20°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Likely species
Mayflies
Caddisflies
- Little Black Caddis (East)Most likelyLower confidenceNearest relative#16–18–20 · Adult
- Green Caddis / Rock WormAlso possibleLower confidence#14 · Adult
- Tan Caddis / Spotted SedgeAlso possibleLower confidenceNearest relative#14–16 · Adult
- October CaddisAlso possibleLower confidenceNearest relative#6–8–10 · Adult
Hatch timeline · tomorrowPeak at 7am
12pm(now) — Grasshopper (Eastern)
Stage: Terrestrials on topApproach: Dry flyActivity: 37%
Also:Trico (Eastern)31%Reed Smut26%
Peak emergence windowWeather boostEmergence building5 food groups active
Peak activity at 7am — Trico (Eastern) (Trico (Eastern), Degree-days at peak)
Sub-surface · on the nymphunder the surface
Hatch predictions
Top nymph shown — see all 4 guilds with Pro.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey(1)
Hatch predictions
Top prey shown — see all 4 with Pro.
Start free trial14-day free trial. Cancel anytime.
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
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
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
Cooler water nearby · 5
Water here at 20.0°C — the fishing's alive, but these are cooler if you'd rather rest the warm water.
Gallery · 1
Terrain map
About this water
A well-known Allamakee County creek near Dorchester, just over the line from Minnesota, with wild and stocked browns and rainbows in cold limestone water. A Driftless favourite that fishes hard and rewards persistence.
- Limestone
Water quality · US Clean Water Act
- Aquatic life: Impaired
- Recreation: Impaired
What this classification means
Recreation: Bacteria/pathogen advisory — mind wading cuts and immersion.
EPA ATTAINS assessment unit 'Waterloo Creek' (IA 01-UIA-253), 2024 Integrated Report. Aquatic Life use: Not Supporting. Listed impairment causes: Pathogens, Cause Unknown Impaired Biota. 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-253
The full read · show the working · for Rainbow Trout · confidence 80%
How the 28 is built — score × weight = contribution
Temperature30 × 28%8.4
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time65 × 13%8.5
Pressure75 × 7%5.3
Insect activity57 × 12%6.8
Conditions total= 62
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.
The dawn and dusk windows score higher than the midday lull.
Directions
Seasons & zones
- Trout Open all year → Open all year
Related guides
Booking & contacts