The USGS gauge on the Oswegatchie in Harrisville provides an "approximation". The benchmarks below have many variables, so make sure you assess each drop yours
After the slots the river splits again around an island with the majority of the water flowing right, the right side has a small water fall with different paths, at low level this is the easier drop. The left has a small 45 foot shoot. At low water this shoot is either dry or unrunnable. Scouting is best on the island if running the rapid or left with portaging the easiest along the left side.