Totally low; nothing but a scrape.
IT IS HIGHLY RECOMMENDED TO SCOUT THIS THOROUGHLY (from river-level) before putting on.
The ledge at the end of the gradient in town is not that big a drop (typically just about 2', more or less), but the hydraulic it forms can be substantial.
The river is wide here (as it is throughout this section), and the lip of the ledge is VERY irregular, thus the shape of the hydraulic varies across the width of the river.