; or (2) cause redirected adverse water supply or fiscal impacts to those within the Sacramento River watershed, the San Joaquin River watershed or the State Water Project service area. (b) Costs To the extent that costs are incurred solely pursuant to or as a result of this title and would not otherwise have been incurred by any entity or public or local agency or subdivision of the State of California, such costs shall not be borne by any such entity, agency, or subdivision of the State of California, unless such costs are incurred on a voluntary basis. (c) Rights and obligations not modified or amended Nothing in this title shall modify or amend the rights and obligations of the parties to any existing— (1) water service, repayment, settlement, purchase, or exchange contract with the United States, including the obligation to satisfy exchange contracts and settlement contracts prior to the allocation of any other Central Valley Project water