The Maipo River is the main river flowing through the Santiago Metropolitan Region and the Valparaíso Region of Chile. It is located just south of the capital of Santiago. The Mapocho River, which flows through central Santiago, is one of its tributaries. Its headwaters are on the west slope of Maipo volcano, in the Andes. The Maipo River is by far the …The Maipo River is the main river flowing through the Santiago Metropolitan Region and the Valparaíso Region of Chile. It is located just south of the capital of Santiago. The Mapocho River, which flows through central Santiago, is one of its tributaries. Its headwaters are on the west slope of Maipo volcano, in the Andes. The Maipo River is by far the major source of irrigation and potable water for the region.