2005 California Government Code Sections 25660-25662 Article 3. Fish

25660.  On the application of any person interested, the board of
supervisors may by ordinance declare all or any portion of any
slough, river, or stream to be a public highway for the purpose of
fishing therein, if it:
   (a) Does not lie within or run through cultivated land lying
within the county.
   (b) Is stocked or supplied in whole or in part with fish by the
state or counties.
   (c) Has not been declared by law to be navigable and in fact is
not navigable for commercial purposes.
   From the time the ordinance becomes effective, the slough, river,
or stream is a public highway for such purpose, subject only to the
reservations contained in this article.
25661.   If any owner of land adjacent to or across which the
slough, river, or stream declared to be a highway for fishing flows
does not consent to its use for such purpose with the right to pass
along the banks for the purpose of fishing and on application refuses
to grant the right of passage to the county by suitable instrument
in writing, the board may contract for and purchase any such rights.
25662.  If the right of passage cannot be purchased at a
satisfactory price, the board may authorize condemnation proceedings
to be commenced to procure the right.