Cal. Gov. Code § 51061
The governing body of any city or county at any time may, by resolution, abandon an open-space easement, if it finds that no public purpose described in subdivision (b) of Section 51056 will be served any longer by keeping the land as open space. No resolution abandoning an open-space easement shall be finally adopted until the matter has been referred to the city or county planning commission, the commission has held a public hearing thereon and furnished a report on the matter to the governing body and the governing body has held at least one public hearing thereon after giving 30 days notice thereof by publication in accordance with Section 6061, and by posting notice on the land.
Prior to approval of the resolution abandoning an open-space easement, the governing body shall direct the county assessor to assess the land, as if the easement did not exist, and to report such new assessed value to the governing body. As a condition of the abandonment of the easement, the owner shall pay to the county or city an amount equal to 50 percent of the new assessed value of the land; provided, however, that the governing body may waive all or any portion of such payment, if it finds that it is consistent with the public interest to do so, and if the waiver is approved by the Secretary of the Resources Agency. Any such payment not waived shall be considered deferred taxes, and a sum equal to the sum actually collected shall be transmitted by the treasurer of the county or city to the State Controller and be deposited in the State General Fund.
Ca. Gov. Code § 51061