Beaverkill-Willowemoc Fishing Report: August 17, 2026

Quick Summary

The Beaverkill and Willowemoc improved on temperature this morning, but they are still summer freestones that need caution. USGS showed the Beaver Kill at Cooks Falls at 561 cfs, 2.81 feet, and 62.2 F, while the Willowemoc near Livingston Manor was 142 cfs, 2.44 feet, and 61.2 F near the morning check. Those readings are fishable, and cloud cover could help olives and terrestrials, but rain has pushed flows higher than yesterday and thunderstorms remain possible. Carry a thermometer, avoid trout if the water climbs toward 68 F, and stay out of fast or freshly colored water.

Conditions Snapshot

Field	Value
Status	Fair. Cooler water and cloud cover help, but rising freestone flows, possible thunderstorms, and warm-water ethics keep the window cautious
Flow	561 cfs at Beaver Kill at Cooks Falls; 142 cfs at Willowemoc Creek near Livingston Manor
Gauge Height	2.81 feet at Cooks Falls; 2.44 feet near Livingston Manor
Water Temp	62.2 F at Cooks Falls; 61.2 F near Livingston Manor during the morning check
Clarity	Not reported by official gauges; treat new rain as a reason to check color at the access before committing
Trend	Higher than yesterday morning on both gauges after rain
Best Window	Morning through the cool, cloudy part of the day; stop for thunder, dirty runoff, or water near 68 F
Best Method	Nymphs and wet flies in faster, oxygenated water; dry flies when olives, ants, or evening mayflies bring fish up safely
Wadeability	Limited. Flows are higher than yesterday, so use normal access cautiously and avoid pushy crossings

Weather

For Roscoe, the National Weather Service forecast calls for mostly cloudy weather, a high near 79 F, light northwest wind, and a chance of showers and thunderstorms. Patchy fog is possible tonight, with a low around 59 F. The cooler, gray start is better for trout than bright heat, but freestones can change quickly under repeated showers; leave the water for thunder or a sudden stain.

River Notes

The Beaverkill and Willowemoc both came up materially from yesterday's morning check. Cooks Falls rose from 366 cfs to 561 cfs, while the Willowemoc near Livingston Manor rose from 81.6 cfs to 142 cfs. Morning temperatures stayed safely below 68 F, which is the useful part of today's report, but rising water makes footing and clarity less predictable than a simple temperature reading suggests.

Dette's same-day public Catskills report showed rain, cool air, and dense cloud cover this morning, with a reminder to carry a stream thermometer. It also pointed to Blue Winged Olives gaining importance as August moves on, flying ants in humid weather, sulphurs tapering, and Isonychias and Light Cahills remaining useful in faster water toward evening. The Beaverkill Horton Brook thermal refuge regulation remains in effect from the Iron Bridge at Horton downstream to the first Route 17 overpass, where angling is prohibited from July 1 through August 31.

Hatch Activity

Official gauges do not report hatches. Same-day Catskills source context supports Blue Winged Olives, flying ants, tapering sulphurs, Hebes, White Flies, Isonychias, and Light Cahills, with temperature and water color deciding how much of that activity is worth fishing over.

Hatch	Size	Notes
Blue Winged Olive	18-22	Clouds and rain make olives the most useful mayfly to watch today
Flying Ant	16-20	Humid weather can put ants on the water around banks, flats, and foam lines
Sulphur	16-18	Still present but tapering; colder water gives this hatch a better chance
Hebe	18-20	Carry small cream or pale mayfly patterns for late-summer mixed hatches
White Fly	12-14	Worth having for evening activity where temperatures remain safe
Isonychia	12-14	Fish nymphs and wet flies in riffles and faster bankside water
Light Cahill	14-16	Useful toward evening in broken current and softer light

Recommended Flies

Category	Fly	Size	Notes
Nymph	Isonychia Nymph	10-14	Start in riffles, pocket water, and faster edges with good oxygen
Nymph	Pheasant Tail, Frenchie, or Hare's Ear	14-18	Match smaller mayflies before surface feeding starts
Nymph	Caddis Pupa	14-18	Work riffles and pocket water when fish stay subsurface
Wet	Soft Hackle Pheasant Tail, Partridge and Orange, or Isonychia Wet	12-18	Swing through broken water during active bug movement
Dry	BWO Comparadun or CDC Olive	18-22	Use for small riseforms under rain or heavy cloud cover
Dry	Flying Ant or Beetle	16-20	Prospect shaded banks and foam seams during humid spells
Dry	Sulphur Emerger, Hebe, White Fly, Isonychia, or Light Cahill	12-18	Carry a late-summer evening mix, but fish it only while temperatures remain safe

Tactics

Start with the thermometer and the water color, not the fly box. If the river is clear enough and still safely cool, fish an Isonychia nymph or smaller mayfly nymph through faster, oxygenated water where trout have cover from the added flow. If olives or ants start bringing fish up, switch to a single dry or dry-and-emerger pair and keep presentations short and accurate. Do not fish the Horton Brook thermal refuge closure, do not wade pushy crossings, and stop targeting trout if readings approach 68 F.

Gauge Links

Gauge	Flow	Temp	Link
BEAVER KILL AT COOKS FALLS NY	561 cfs	62.2 F	USGS 01420500
WILLOWEMOC CREEK NR LIVINGSTON MANOR NY	142 cfs	61.2 F	USGS 01419500

Sources

Official sources checked: USGS stations 01420500 and 01419500, plus the National Weather Service forecast for the Roscoe, NY area. This report is an original Custom FlyBox summary based on current official gauge and weather data, with local public conditions reports reviewed separately for hatch, method, closure, and safety context.