Vegetable production covers near 100% of needs, the country grows dates, tomatoes, cucumbers, watermelons, cereals, herbs, potatoes and also flowers. Saudi Arabia reaches the under-ground rivers and lakes by drilling through the desert floor and directly irrigating the field with circular sprinklers systems or center-pivot irrigation on a radius ranging from 300 to 500 m. These waters are a non-renewable resource, hydrologists estimate the reserve for about 50 years.