Waterlands
River Intelligence · Entomology

Read the Water. Match the Hatch.

Every river has an entomological fingerprint — the bugs it grows, when they hatch, and how trout eat them. Learn the bugs, cross-reference live flows, and fill your box before you go.

Hatching NowPale Morning DunGreen DrakeTricoSulphurSmall Western Red QuillFlavGray DrakeCallibaetisSpotted SedgeGolden StoneYellow SallyBrown DrakePink LadyTerrestrialsScuds & Sowbugs
EncyclopediaHatch CalendarRiver FingerprintsMatch the HatchBug School
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Henrys Fork
Railroad Ranch (Harriman) · ID · USGS 13042500 · 44.4167, -111.3947
The graduate school of dry-fly fishing. A giant spring creek whose flat water grows huge, selective rainbows — and the densest mayfly calendar in the West.
1,330
CFS
—
Water Temp
4.6
Fair
Flow vs Hatch Likelihood
Flow CFS
Hatch %
7-day trend — flows dropping, Flav likelihood at 100% and climbing. Seasonal likelihood — the gauge supplies no live factors.
−7d
−6d
−5d
−4d
−3d
−2d
−1d
Today
The Fingerprint
Mayfly-dominant spring creek. Silt and weed beds grow crawler and swimmer mayflies in absurd density; stoneflies matter only on the canyon edges.
Fly Box for Right Now
Flav Sparkle Dun #14-16
Flav · Dun
$3.15
Parachute Flav #14
Flav · Dun
$3.25
Parachute Adams #14-16
Callibaetis · Dun
$2.95
Callibaetis Comparadun #14
Callibaetis · Dun
$3.15
Parachute PMD #16-18
Pale Morning Dun · Dun
$3.25
Comparadun PMD #16
Pale Morning Dun · Dun
$3.15
Hatch Chart — Henrys Fork
River-specific intensity: this water, these bugs. Click a bug for its full profile. Likelihood is seasonal — this gauge supplies no live factors.
≋ Waterlands · Hatch data blends USGS gauges, NOAA temps & regional emergence records
USGS Real-time Data · Free to Start · No Credit Card