 14 m3/s more water would be mobilized from various sources.The largest of these imports (5 m3/s) will consist of groundwater from the Tula Valley North of Greater Mexico, where the groundwater table has increased from many years of irrigation with untreated wastewater, at a cost of US$255 million.The second-largest source of additional water will be mobilized through an exchange of treated wastewater for clean water at present used for irrigation in the Vaso del Christo area (4 m3/s), at a cost of 140 million.