Salt deposits fill the former bed of the Colorado river in its Mexican delta. The Colorado River delta has hardly seen any Colorado water in the past 30 years. The 1.5 million acre feet of water that the USA delivers across the border into Mexico is completely used by cities like Tijuana and Mexicali. The majority, though goes into the irrigation of the vast agricultural area that covers the northern part of the delta. The line of agricultural fields slowly moves northwards though due to an increasing salinity of the area.