The Behavior of Rivers 



39 



to low hills. When the hills are practically all gone the stream 

 has reached its ultimate limit and is essentially "dead," and the 

 landscape is mature or "old." It has reached base-level, the 

 ultimate of all lands that are above the sea. 



Photo by G. W. Stose, U. S. Geol. Survey 



FIG. 12. Tidal lagoon at mouth of San Luis Obispo Creek, showing how 

 streams behave when they cannot get into the ocean. 



California Rivers Not So Simple 



Some of California's rivers are old, but the principal rivers 

 that flow in well defined valleys have not come into existence 

 in the manner that has been described. Rivers such as have 

 been described are spoken of as consequent rivers, because they 

 follow as a consequence the topography of the land. Water 

 runs down hill and erodes as it runs. If not disturbed this 

 would be the natural method of development of drainage 

 streams. Along the coast where the land has but recently been 

 uplifted above the sea streams that follow the simple pattern 



