Lajas Valley is plagued with salinity and waterlogging problems of the soils. Use of brackish (500 milligrams per liter) ground water for irrigation compounded the problem until an irrigation-drainage system was constructed in 1955.
Lajas Valley is an alluvium-filled trough between volcanic and limestone highlands. The alluvium, mostly clay and as much as 300 feet (90 meters) thick, contains brackish ground water except in the recharge areas located along the foothills. Artesian conditions exist in the eastern part of the valley where upward hydraulic gradients have increased due to the addition of irrigation water in the recharge areas.
Wells yield up to 200 gallons per minute (13 liters per second) from alluvial fan deposits in the recharge areas. Wells tapping the buried limestone aquifer in the northwest will yield as much as 2,000 gallons per minute (126 liters per second).
Results from a digital models show that a network of discharge wells could alleviate waterlogging of the soils in the artesians
