Like partners doing a tango, two rivers in Nunavut, Canada, become a single unit without losing their individual appearance as they move sinuously across the tundra. The darker Back River flows north toward the Arctic Ocean. Along the way, its tributary, the Hayes River, a light, milky blue, joins it but remains visually distinct for about 10 miles beyond the confluence. Only when the merged rivers enter their final destination of Chantrey Inlet do the waters begin to blend. This phenomenon of two rivers that are joined yet distinct is…
