Throughout his career, Ryan has helped develop successful legislation relating to water rights, tribal rights and the environment. While in the Senate, he played a major role in ushering through a number of Indian water settlements totaling nearly $1 billion, including the White Mountain Apache Tribe Water Rights Quantification Act, and a $3.4 billion settlement of financial mismanagement claims brought by American Indians against the United States Department of the Interior. The White Mountain Apache settlement, which was Ryan's primary responsibility, authorizes $292 million in federal funding for the White Mountain Apache Tribe in consideration for the tribe waiving its water rights claims against the United States.
Ryan’s work on the Arizona Water Rights Settlements Act resulted in an amendment to the Act to ensure that the underlying legislation, which authorized the largest Indian water settlement in United States history, became effective.
He was also instrumental in obtaining the authorization of approximately $313 million in federal funding to cover the federal government’s share of the cost of a comprehensive, cooperative effort among 50 federal and non-federal entities in Arizona, California, and Nevada to protect and maintain wildlife habitat along the Colorado River. This legislation, The Lower Colorado River Multi-species Program Act, also provides assurances to the affected water and power agencies of the three states that their vital river operations may continue as long as they comply with the applicable conservation program.