Photo taken in 1915 showing bay reclamation in work, both the old and new Santa Fe Depots at Kettner and Broadway, and the San Diego Gas and Electric Building. In the 1900s, San Diego Bay was a fertile, shallow bay supporting tremendous biodiversity in its open water, salt marshes and mud flats. The Bay changed dramatically. Navigation channels were dredged. Mudflats and salt marshes were filled. More than 90 percent of the mudflats and 78 percent of the salt marshes were eliminated and those that remain are found mostly in South San Diego Bay.