Today’s Video of the Day from the European Space Agency features San Francisco Bay in California. The shallow estuary is surrounded by an extensive metropolitan area that includes major cities like San Francisco and Oakland. In the image, green forests and parks are easy to distinguish from urban areas.
The Sacramento-San Joaquin River Delta appears brown from sediment as it flows into San Pablo Bay. In the bottom right portion of the photo, salt ponds in the Don Edwards National Wildlife Refuge appear bright green and yellow.
The Golden Gate Bridge is visible crossing the opening of the bay into the Pacific Ocean between Marin County and San Francisco. The bay was searchable as far south as San Jose until the 1850s, when hydraulic mining released large amounts of sediment from the rivers that settled in those parts of the bay that had little or no current.
Later on, the wetlands and inlets were deliberately filled in, reducing the Bay’s size since the mid-19th century by as much as one third. Recently, large areas of wetlands have been restored, further confusing the issue of the Bay’s size.
Despite its value as a waterway and harbor, many thousands of acres of marshy wetlands at the edges of the bay were, for many years, considered wasted space. As a result, soil excavated for building projects or dredged from channels was often dumped onto the wetlands and other parts of the bay as landfill.
Treasure, Angel and Alcatraz islands can also be seen in the photo, along with several bridges connecting the eastern and western shores of San Francisco Bay.
Video Credit: ESA
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