According to data from the Food and Agriculture Organization of the United Nations (FAO), groundwater supplies half of the world's population with fresh water and makes up 43% of the water used in irrigation. Despite its importance, it is calculated that about a third of the world's greatest aquifers are drying up quickly and that 20% are being overexploited. In Spain, a country where a large number of crops are watered with groundwater, scientific data show that the extraction rate is much higher than the water replenishing rate.