When a contract has been entered into between the United States and an irrigation district, the district shall not be dissolved nor shall the boundaries be changed, nor shall any specific parcel of land be released or discharged from the outstanding bonded indebtedness of the district, in pursuance of bonds deposited with or transferred to the United States, by payment of a proportion of such indebtedness as provided in this article, except upon the written consent of the secretary of the interior filed with the official records of the district. If consent is given and lands are excluded, the excluded lands shall be free from all liens and charges for payments to become due to the United States.