That a right-of-way of not exceeding five hundred feet in width is hereby granted to the United States of America through any lands or shorelands belonging to the state of Washington, or to the University of Washington, and lying in King county between Lakes Union and Washington, or in or adjoining either of them, the southern boundary of such right-of-way on the upland to be coincident with the southern boundary of the lands now occupied by the University of Washington adjacent to the present right-of-way of said canal; the width and definite location of such right-of-way before the same is taken possession of by said United States shall be plainly and completely platted and a plat thereof approved by the secretary of war of the United States filed with the department of natural resources: PROVIDED, That nothing in this section contained shall be construed to repeal or impair any right, interest, privilege or grant expressed or intended in the act of the legislature of the state of Washington approved February 8, 1901, entitled, "An Act relative to and in aid of the construction, maintenance and operation by the United States of America of a ship canal with proper locks and appurtenances to connect the waters of Lakes Union and Washington in King county with Puget Sound and declaring an emergency."