Estero Pupio, also known as Río Conchalí, is a natural watercourse located in the Coquimbo Region of Chile. It originates in the foothills of a transverse mountain range and its basin is part of this region. The water body forms approximately 10 kilometers inland and flows to the Pacific Ocean, discharging immediately north of the coastal town of Los Vilos. This geographical setting suggests a watercourse that traverses from inland hills to a coastal plain. The proximity to Los Vilos indicates a potential access point for paddlers near its mouth, though specific put-in or take-out locations are not detailed. The overall character is that of a regional stream or small river system within a coastal basin. The area's aesthetic is defined by its connection to the transverse mountain range at its headwaters and its terminus at the ocean near a populated coastal area. Specific paddling hazards, seasonal water levels, water temperature, water quality, facilities for paddlers, recommended routes, wildlife, regulations, or historical significance are not detailed. Paddlers should conduct thorough local reconnaissance, as the description outlines the watercourse's basic geographical formation and location.