Piney River (Nelson County) - 1.) The "Big Piney" (Alhambra to VA. 827 ['Perkins Mill Rd'] Woodson) (VA)
400 to 450 is a good guide to minimum flow. The upper range of flow will, of course, vary depending on individual groups' skill level and disposition.
The second of the four bigger rapids. Take the right channel around the island. The right channel clearly carries more water than the left channel. Run the lead in and then cut left at the bottom just passing the end of the island.