It tells you how difficult the rapid is to paddle - 1 being basically flat water, 5 generally the highest that can be paddled. This website explains it https://

It tells you how difficult the rapid is to paddle - 1 being basically flat water, 5 generally the highest that can be paddled. This website explains it https://gopaddling.info/river-gradings-simple-guide/ https://gopaddling.info/river-gradings-simple-guide/