Tailwater · Mixed Metamorphic · Maryland

Gunpowder Falls

The Gunpowder below Prettyboy Dam is a small miracle — a seven-mile tailwater of wild brown trout half an hour north of downtown Baltimore.

Species

A proper day on the water

Low and clear — careful approach country. Stay small, stay accurate.

75% confidence in this read
Water temperature for brown trout
Cool — slow
9°C est.ideal 10–16°C
0°14°28°
Why this score · for brown trout
  • Temperature8228% weight
  • Flow8022% weight
  • Clarity9518% weight
  • Feeding Time5013% weight
  • Pressure807% weight
  • Insect activity4712% weight
Conditions
Level
Dry recently
No gauge reading
Water temp
9.0°C
Estimated
Clarity
Clear
Air temp
24°C
Wind
SE 5 km/h
Calm
Pressure
1021 hPa
Rain · 24h
0.0 mm
No rain
Rain · ahead
0.0 mm
No meaningful rain · next 48h

Live readings — water temperature is an estimate where the gauge does not record it.

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
Good — water clarity is right today, though insect activity could be better.
Through the year
0–3 scale · June 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
Black MidgeHatch
2
3
3
3
3
3
3
3
3
3
3
2
Freshwater ShrimpHatch
2
3
3
3
3
3
3
3
3
3
3
2
Western Blue-Winged OliveHatch
2
3
3
3
3
3
3
3
2
Pale Morning DunHatch
2
3
3
2

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

Permits & access
Permit required — see local rules.
  • Maryland licence required; catch-and-release wild trout regulations on the tailwater reach — verify current MDNR rules and the fly-fishing-only sections.
Directions
Apple MapsGoogle Maps
About this water

The Gunpowder below Prettyboy Dam is a small miracle — a seven-mile tailwater of wild brown trout half an hour north of downtown Baltimore. Back in the eighties, Maryland's DNR and Trout Unlimited talked the dam operators into a guaranteed minimum cold release, and the browns took it from there; the river hasn't been stocked since, and it doesn't need to be. It's tight, technical, tree-lined water — sulphurs and caddis in season, midges and scuds the rest of the year, and trout that have seen every fly in the box. Read the release out of Prettyboy and fish small.

  • Mixed metamorphic
Seasons & zones
  • Trout1 January → 31 December