The largest lake in Cos­ta Rica. The alti­tude is 600 m. The Are­nal vol­cano is near­by. The lake increased in size three times after the con­struc­tion of the hydro­elec­tric dam in 1979. Dur­ing the fill­ing, sev­er­al small towns were flood­ed. The lake area is 80 square kilo­me­ters. The hydro­elec­tric pow­er sta­tion pro­duces 70% of the elec­tric­i­ty in Cos­ta Rica. Lake Are­nal pro­vides water to the region and province of Gua­nacaste. Area: 85,589996 sq. km., vol­ume: 2220 cubic meters, depth avg: 25,9 m, shore length: 125,03 m.