Lake Arenal: This natural depression caused by local geological faults formerly contained a small lake that emptied into the Arenal River which flowed into the Caribbean via the San Carlos and San Juan Rivers. However, in the 1970's, the Costa Rican Electric Company (I.C.E.) began construction of what is currently the country's largest hydroelectric generating project.
An earthen dam was built only seven kilometres (4.3 miles) to the west of Arenal Volcano--that had erupted violently just a few years earlier. As the waters filled up behind the dam a thirty-kilometre long lake was formed. Water from the lake is tunnelled to the Pacific side of the country, passing through three turbine-driven generating stations, before being channelled into a system of irrigation canals that have substantially increased the agricultural productivity of the lower Tempisque basin in Guanacaste.
An earthen dam was built only seven kilometres (4.3 miles) to the west of Arenal Volcano--that had erupted violently just a few years earlier. As the waters filled up behind the dam a thirty-kilometre long lake was formed. Water from the lake is tunnelled to the Pacific side of the country, passing through three turbine-driven generating stations, before being channelled into a system of irrigation canals that have substantially increased the agricultural productivity of the lower Tempisque basin in Guanacaste.
