Aerial view of the Tijuana River National Estuarine Research Reserve looking southeast toward the U.S./Mexico Border and the city of Tijuana.
Aerial view of salt evaporation ponds in San Diego Bay, California. Salt evaporation ponds are shallow man-made ponds designed to produce salt from sea water. The seawater is fed into large ponds and water is drawn out through natural evaporation which allows the salt to be subsequently harvested (wiki 2009)