Tex. Auxiliary Water Laws § 7852

The directors shall have full power to co-operate and act with the United States or any officer or department thereof, in any manner pertaining or relating to the construction and maintenance of any improvement, whether by survey, work or expenditure of money made or to be made, either by the directors or by Federal authority, or both. Such directors shall have authority to agree and consent to the United States entering upon and taking the management and control of said work of construction, repair or reconstruction and maintenance, in so far as it may be necessary or permissible under the laws of the United States and the regulations and orders of any department thereof.