The Laguna del Maule lake lies on the crest of the Andes, within a depression with a diameter of . The lake has a depth of and covers a surface of ; the surface is at an altitude of . The name of the volcanic field comes from the lake; the Maule river originates there and the Barrancas River has its headwaters in the volcanic field as well. Terraces around the lake indicate that water levels have fluctuated in the past; the lake is regulated by a dam at the outlet that was built in 1950. An eruption dated between 19,000 ± 700 and 23,300 ± 400 years ago dammed the lake higher than its present level. When the dam broke 9,400years ago, a lake outburst flood occurred that was long and left traces, such as scour, in the down-valley gorge. Benches and beach bars developed on the lake, which has left a shoreline around Laguna del Maule lake. Additionally, tephra fallout has impacted the lake through the Holocene and affected life in the lake waters.