Federal Water and Environmental Law

Despite numerous efforts to minimize conflicts, federal and state laws regarding water often conflict.  In this context, two types of federal law are most important: reserved rights, and environmental law.  Federal reserved rights specify that all lands set-aside for special uses by the federal government automatically (and in perpetuity) include a reservation of water in a sufficient quantity to fulfill the purposes of that land, with a priority date corresponding to the date of land designation.  This principle applies to all types of federal lands, including national parks, national forests, wildlife refuges, military installations, and so on, as well as including Indian reservations.  See:

Overview of Federal Reserved Water Rights, by the Bureau of Land Management.

Securing Arizona's Water Future (2002), an overview of Indian and Federal Reserved Rights, particularly in Arizona, produced by the Arizona Department of Water Resources.

Winters v. United States (1908), the landmark federal case that established Indian reserved water rights

Also important are federal environmental laws, particularly the Endangered Species Act and Clean Water Act, which can place limits on the exercise of private water rights held under prior appropriation systems.

The Red Lodge Clearinghouse provides an overview of many federal laws and regulations, including:

The Endangered Species Act

The Clean Water Act

National Environmental Policy Act (NEPA)

Wilderness Act