255 



San Francisco Bay is primarily the drainage from the Central Valley 

 of California; the Sacramento River from the north and the San 

 Joaquiin from the south form a huge rich delta which is connected to 

 the bay. The overall size not including the tidal delta area is about 435 

 square miles at mean high water. 



In 1850, when California was admitted to the Union, San Francisco 

 Bay was even larger than it is today. More than 300 square miles of 

 marshlands along its shores gave it the appearance of being extraor- 

 dinarily vast, particularly during maximum spring tides when the 

 bay waters flooded far inland, drowning all but the tips of reeds and 

 marsh grasses. Since those early days more than 240 sc[uarB miles of the 

 salt marshes have been reclaimed, chiefly for agriculture and salt 

 ponds. In addition, approximately 17 square miles of tidal and sub- 

 merged lands have been filled, mostly along the waterfronts of San 

 Francisco, Oakland, and Richmond; in Richardson and San Rafael 

 Bays in Marin County ; and along the northern bayshore of San Mateo 

 County. And yet the bay still seems so immense that it intrigues many 

 minds with the possibilities of reclaiming additional square miles for 

 industrial and residential developments, recreation areas, airports, 

 highways, and commercial establishments. 



Tlie bay presents few obstacles to reclamation through land fill. It 

 is shallow throughout much of its area, with 80 percent of the water 

 less than 30 feet deep and 70 percent less than 18 feet deep at low-tide 

 references. About 248 square miles of tidal and submerged lands in the 

 bay are still susceptible to reclamation. If these areas were filled and 

 used for urban purposes, only 187 square miles of the bay would re- 

 main as deepwater channels for ships and many portions of the bay 

 would be reduced almost to rivers. 



This example shows the magnitude of reclamation that can occur 

 without consideration of future consequences. A total damage assess- 

 ment has not been made, but there has been a drastic decline or elimina- 

 tion of clam and shrimp fishing within the bay. When nursery areas 

 of the size of San Francisco Bay are damaged this damage must be 

 reflected in the life of the adjacent coastal waters (IV-5-5) . 



Mission Bay^ San Diego^ Calif. 



Mission Bay in California is one of the better examples of deliberate 

 modification to intensify use. In fact, this unique case demonstrates 

 what can be accomplished through coordinated Federal, State, and 

 local planning and construction. The end result has added considerable 

 value to the community and has preserved a portion of the estuarine 

 environment in a metropolitan area (fig. IV.5.15). 



Mission Bay and San Diego Bay lie in the delta of the San Diego 

 River. Prior to about 1825 the river would switch channels and flow 

 into one or the other, depending on the whims of nature. Between 1826 

 and 1877, history shows the San Diego River channel emptying into 

 San Diego Bay. Since San Diego Bay was one of the best natural 

 harbors on the Pacific coast, the shipping interests became very con- 

 cerned over the sediment load deposited in the harbor. It was felt that, 

 if this sedimentation process were not controlled, the bay would be 

 come too shallow for navigation. 



Consequently, in 1877 the San Diego River was permanently di- 

 verted into Mission Bay. The period from 1900 to 1950 was one of 



