Cal. Fish & G. Code § 5991
In lieu of the department's ordering the owner to install a screen the department may, at its option, elect to construct and install the screen itself, in which event the type, size, mesh, and location of the screen and the time within which it shall be installed shall be determined as provided by Section 5992 of this code.
When the department elects to construct and install a screen, one-half of the cost of construction and installation shall be paid by the owner.
The department may pay the entire cost of the construction and installation of a screen from the Fish and Game Preservation Fund, in which case it shall, upon completion of the screen, notify the owner of the amount of one-half of the cost, and the owner shall, within 30 days thereafter, remit that amount to the department.
Ca. Fish and Game Code § 5991