C.R.S. § 37-62-102: When compact operative.

Said compact shall not become operative unless and until the same has been ratified by the legislatures of each of the signatory states and consented to by the congress of the United States. The governor of the state of Colorado shall give notice of the ratification of said compact to the governors of the states of New Mexico, Utah, Wyoming, and Arizona, and to the president of the United States.