The carved relief affects the course of hydrographic run-off, which is accentuated by torrential precipitation in the region, resulting in accentuated erosion and deposition along the margins. A majority of the watercourses are temporary or torrential, with the greatest run-off occurring in the winter, and little in the summer, with few permanent ravines. There are only two permanent effluents in the lake, one to the western crater rim in Barrosa, and the other in the south-southeast. The lake is maintained from mainly, direct precipitation over the caldera and from superficial run-off from the watersheds, where nutrient infiltration is common. The lake's waters support local aquifers in the lowlands and provide potable water to the settlements in the southern flanks of the caldera.