In reply to Fredt:
River, and lake, levels are freely available on line.
For a similar crossing in the Duddon valley or the Thirlmere boulders I look at the levels at the nearest measuring station.
Fickle steps , if the river level is above 1.0 m I know its not passable, 0.7 m is not too scary. Highest recorded is something like 2m.
Worth taking note of levels if you go often.