Kootenay — Drift & Float Suitability
The whole Freshwater Atlas network, graded by river size — with the hazards size can't see drawn on top: canyon confinement (DEM wall-rise on both banks), verified whitewater ratings (American Whitewater), and the falls and cascades that force a portage. A green line through red dashes is not a float. Cross-check with the raw gradient / channel-width overlays; click any reach for its numbers.
Suitability is estimated from stream order (river size). Canyon confinement is DEM-derived (SRTM 30 m): the elevation rise found on both banks within 300 m of the channel — thresholds validated against American Whitewater grades, but still an estimate. Amber means verify before you float; red means assume whitewater. Falls and cascade points are Province of BC FISS obstacles. The gradient and channel width overlays are per-segment values from bcfishpass (S. Norris / hillcrestgeo.ca) across the floatable network (stream order 3+, vector-tiled) — the raw drivers, so you can validate or overrule the size-based suggestion. Gradient is DEM-derived and clamped for display; treat extremes as approximate. Data © Province of BC (OGL-BC): Freshwater Atlas, FISS. Whitewater ratings © American Whitewater. Terrain: Mapzen/AWS terrain tiles (SRTM). Bases: Esri · © Province of British Columbia · © OpenTopoMap (CC-BY-SA) · © OpenStreetMap contributors · © CARTO. Flows and hazards change fast — always scout before you float, and never enter a canyon you haven't verified an exit from.