Water is essential for human health. It is also a critical factor for achieving food security and plays an essential role in sustaining ecosystem services. From the origins of civilization water has been managed by humans to provide for their basic needs and to enhance agricultural production through irrigation. Artificial water resource systems have been developed to modify the natural conditions of water bodies in order to provide adequate reliability on water supply to users through water abstraction, storage, transportation and distribution. These systems have protected humans from the irregularities of the water cycle, but they have also produced significant alterations of natural systems, particularly in areas with less and more irregular water resources. Prolonged absence of precipitation and soil moisture deficits do not necessarily mean water scarcity because water can also be obtained from natural or artificial reservoirs: snow pack, aquifers and regulation dams can sustain water demands during periods of meteorological drought. However, population growth and climate change are increasing the challenges facing water supply systems. Population dynamics, growing demands, pollution, land use changes and other factors frequently contribute to the failure of some water supply systems. In this context, it is believed that climate change augments the existing pressure on water resources, because

Climate change and water resources for agriculture Climate change and water resources for agriculture

a significant reduction of natural water resources is expected in many areas, in addition to an increase in the frequency of drought episodes and their intensity.