Season: April and May are generally the best months for the Grass, but Oct and Nov also offer windows of boatable flows following three or four days of good rain.
Flows: The USGS gauge on the Oswegatchie in Harrisville provides an "approximation". The benchmarks below have many variables, so make sure you assess each drop yourself, especially at MED and HIGH flows. If Harrisville gauge is rising:
MIN:750-800cfs (3.5') - You will scrape in numerous areas, but have enough for the main drops.
MED: 1100cfs (4.0') - Only slight scraping, but holes are tame.
HIGH: 1700 (4.75') - Ratchet up the difficulty of all rapids at least half a level. Holes are bad!
If Harrisville guage is dropping add 150 cfs to the flows above.
Visual "Gauge": Check the Graffiti on the river right rock just below the bridge in Degrasse. If water is rising and touching the bottom of the "heart", then you can scrape down the wide places and have good water for the drops. If water is dropping then middle of "heart" is the MIN mark.
|WEST BRANCH OSWEGATCHIE RIVER NEAR HARRISVILLE NY|
|usgs-04262500||800 - 2000 cfs||IV-V||01h34m||39.5 cfs (too low)|
Reports give the public a chance to report on river conditions throughout the country as well as log the history of a river.
|Grasse [ny]||Grasse, Twin Falls||900 cfs||simon wiles|
|Lower S. Branch of Grass River [NY]||Basford Falls 3||High!||Tim Kelley|
|Lower S. Branch Grass River [NY]||Twin Falls||n/a||Tim Kelley|
|Grass River [NY]||Large Marge (Rainbow Falls)||n/a||Tim Kelley|
|Grasse River [NY]||Iron Bridge||n/a||Tim Kelley|
|6y153d08h22m||/Grass, Lower S. Branch-Twin Falls [NY]||Grass wood||0 cfs||Jim Dobbins|
|7y134d19h26m||/Grass, Lower S. Branch-Twin Falls [NY]||Basford Falls||900 cfs||Gregory R. Miller|
|7y134d19h33m||/Grass, Lower S. Branch-Twin Falls [NY]||Sinclair||750 cfs||Gregory R. Miller|
|7y134d19h37m||/Grass, Lower S. Branch-Twin Falls [NY]||Twin Falls||1500 cfs||Gregory R. Miller|
|7y135d17h00m||/Grass, Lower S. Branch-Twin Falls [NY]||Adrenaline Falls||1500 cfs||Gregory R. Miller|
|7y135d17h08m||/Grass, Lower S. Branch-Twin Falls [NY]||Twin Falls||n/a||Gregory R. Miller|
|> 10 years||Grass, Lower S. Branch [NY]||Twin Falls||n/a||Glenn Wallace|
|> 10 years||Grass, S. Branch [NY]||Grass River||n/a||Patrick Rogers|