The Judes Lagoon is a karst wetland located in the town of Judes, within the municipality of Arcos de Jalón, in the province of Soria, Castile and León. It is the only lagoon of its kind in the province, as most are of glacial origin.
Judes Lagoon is a lagoon formed by the subsidence of limestone (karst) terrain. It usually has water at the end of winter and in spring. In wet years, it overflows, and the excess water flows down to the Almuguera de Chaorna stream, forming beautiful waterfalls called Chorroneras, very close to the town.
In summer it is likely to be dry. I advise following the tracks marked by IMBA in the area before the GR86 which has non-cyclable sections in the middle of the field