16 



more than 50 feet below present sea level and possibly extended 

 as much as two to three miles seaward from the present shore- 

 line, presumably toward Santa Monica Canyon. According to 

 Layne (1935), the Los Angeles River was flowing through Ballona 

 Gap in 1815 and continued until 1825 (Kenyon, 1951) when a 

 particularly severe flood diverted the river to the south 

 where it joined the San Gabriel River emptying into San 

 Pedro Bay. Other extensive floods in 1862 and 1884 caused 

 part of the waters to return temporarily to Ballona Creek, but 

 since 1884 the Los Angeles River has discharged only into San 

 Pedro Bay (Troxell and others, 1942). 



The mouth of the stream apparently migrated north and 

 south of the Ballona Creek outlet, for the earliest U. S. 

 Coast and Geodetic topographic maps show the natural outlet 

 discharging at the end of a long ssuid spit, while landward 

 of the split there was a salt marsh averaging about one mile 

 in width. In 1906 and 1908 the outlet was "fixed", but in 

 1936 it was again moved 1,400 feet farther to the north. 



At the present time Ballona Creek has a drainage area 

 of approximately 131 square miles from the southern slopes 

 of the Santa Monica Mountains and parts of Baldwin Hills 

 (Fig. 3). Since the construction of flood control channels ^ 

 and other works by man, little detrital material is brought 

 to the bay through this course. 



Probably the most important rifting in the Los Angeles 

 Basin is the Inglewood -Newport fault zone, which occurs in 

 the vicinity of Ballona Creek. Three faults which run 

 perpendicular to the old channel are associated with this 



