Apart from the lake in the caldera, the area of Payún Matrú is largely devoid of permanent water sources, with most water sites that draw in humans being either temporary so-called or ephemeral. Likewise, there are no permanent rivers in the field and most of the precipitation quickly seeps into the permeable or sandy ground. The whole massif is surrounded by sandy plains, which are simply volcanic rocks covered by aeolian sediments; the plains also feature small closed basins which are also found in the lavic area.