California Code, Fish and Game Code - FGC § 6021

The department shall examine new or existing conduits, and may install, maintain, repair, and replace fish screens, bypasses, or other devices to prevent the passage of fish through a conduit, when in the opinion of the department such a screen or device is practical and necessary.  The owner of a conduit shall grant to the department the right of access to the conduit for the installation and maintenance of the screen, and shall provide the department with an easement for a site for the installation of the screen or device deemed suitable by the department.  The owner shall also supply sufficient water for a bypass to carry fish stopped by the screen or device back to the channel from which they were diverted, and an easement for the bypass channel, but such easement shall not require the acquisition or leasing of additional lands by the owner.  No water for a bypass shall be required if the channel from which the water is diverted is dry or incapable of supporting fish life below the point of diversion.