The lands belonging to the state of Idaho between the ordinary high and low water mark at said Big Payette Lake, as well as all other lands of the state adjacent to said lake which are not held in trust for the beneficiaries of the endowed institutions, are hereby declared to be devoted to a public use in connection with the preservation of said lake in its present condition as a health resort and recreation place for the inhabitants of the state and said public use is hereby declared to be a more necessary use than the use of said lands as a storage reservoir for irrigation or power purposes.