Cal. Gov. Code § 8686.2
When the United States or any agency thereof is to provide disaster relief funds for any portion of the cost of a project, the amount so provided shall be deducted from the cost of the project in determining the amount to be allocated by the state and the amount to be contributed by the local agency under Section 8686. It shall not be required that the disaster relief funds to be provided from federal sources shall be paid into the State Treasury, but the secretary shall, if state funds are available, authorize the work to be commenced when the director has received assurance, adequate in his or her opinion, that the federal disaster relief matching funds will be made available for expenditure for the work, or for payment to the state for performance thereof.
Ca. Gov. Code § 8686.2