Del Larraun

Called the nacedero de Aitzarrateta or Ercilla spring, it is the main spring on the northern flank of the sierra de Aralar and one of the main springs of the Comunidad Foral Navarra. The cavity has 355 metres of development and 58 metres of vertical drop.

Since 1953 the first exploration was carried out by I.P.V. Later, in 1987-88, members of the now-defunct Agrupación Deportiva Tritón began diving in it, with the collaboration of the Government of Navarra and the help of Mr. Isaac Santesteban and Carlos Acaz, and they managed to reach 100 metres of development and -26 metres of vertical drop. In 1988 the Grupo A. D. Tritón, with the collaboration of the G. E. Estella and with more modern equipment and techniques, went deeper to the vertical drop and length mentioned above.