	Introduction

As an increasing number of communities in the United States face significant flooding, droughts, and degradation of water quality, interest in the management of interstate water basins has heightened. Interstate water management requires a number of interests to be balanced, including different priorities among states affected by the particular water basin, federal interests in federal water projects, and private interest groups who may be affected by regulation of the basin. Because of these competing interests, interstate water management often becomes controversial and may lead to lengthy legal disputes among the parties. This report explains the legal authority of the federal and state governments to manage water resources. It also examines the role of interstate water compacts to address management issues in interstate water basins. The report analyzes efforts made to resolve disputes in the Chesapeake Bay to illustrate the concurrent roles that states and the federal government may play in managing interstate water resources. The states have claimed authority to control the water resources within their own boundaries. Constitutional Authority of Federal Government to Regulate Waterways

The Commerce Clause of the U.S. Constitution grants the federal government broad authority over water resources within the United States, empowering Congress "to regulate Commerce ... among the several States." The U.S. Supreme Court has interpreted the Commerce Clause broadly. Thus, although the federal government often defers to states' authority regarding allocation and water management, a state's authority over its waters is "subject to the power of Congress to control the waters for the purpose of commerce." Interstate Agreements and Authority for Water Compacts

The competing interests of the federal and state governments may result in disputes over the management of water resources in interstate basins. The U.S. Constitution generally requires congressional consent for such an agreement between states, but does not specify a particular procedure for states to enter compacts. The U.S. Environmental Protection Agency (EPA), the Chesapeake Bay states, and private regional interests have entered a number of interstate agreements in efforts to address the issues facing the watershed, as discussed below. Federal and State Roles Under the Clean Water Act

The CWA governs pollution of the nation's waterways. The 1987 Agreement identified a number of broad goals and set specific objectives related to each goal. Litigation Concerning the Sufficiency of State and Federal Action in the Chesapeake

Although the federal government shares legal authority over water management with the states under constitutional and statutory law, the role that the federal government has taken in the Chesapeake Bay has been challenged in a number of cases.
As an increasing number of communities in the United States face significant flooding, droughts, and degradation of water quality, interest in the management of interstate water basins has heightened. Interstate water management requires a number of interests to be balanced, including different priorities among states affected by the particular water basin, federal interests in federal water projects, and private interest groups who may be affected by regulation of the basin. Because of these competing interests, interstate water management often becomes controversial and may lead to lengthy legal disputes among the parties, as has been the case in the Chesapeake Bay watershed.
The federal government has broad authority over water resources within the United States under the Commerce Clause of the U.S. Constitution. Under the Commerce Clause, the U.S. Supreme Court has ruled that Congress has "superior power" to ensure the navigability of the nation's waterways. Although states generally have a legal right to the waters within their borders and Congress traditionally has deferred to states on a number of water resources issues, the states' rights to control waters within the state is subject to Congress's authority under the Commerce Clause. Because many water resources issues often affect water basins that span several jurisdictions, states may seek to cooperate in the resolution of such issues through interstate water compacts. The U.S. Constitution generally requires congressional consent for such an agreement, which, when it is approved by the states and Congress, becomes binding law and provides for a uniform system of regulation of the water basin among the states.
The Chesapeake Bay illustrates the complex issues involved in interstate water basins. To address concerns regarding the impacts of pollution, the federal government, states, and private organizations have sought to apply water quality protections provided under the federal Clean Water Act (CWA). Additionally, a number of interested parties have entered voluntary agreements committing them to particular goals and actions related to restoring the resources of the Chesapeake Bay, though none of the agreements has been an interstate compact. The lack of progress toward the goals set by the parties has resulted in a number of lawsuits and increased federal attention and action with respect to setting pollution reduction requirements in the Bay.
This report explains the legal authority of the federal and state governments to manage water resources. It also examines the role of interstate water compacts to address management issues in interstate water basins. The report analyzes efforts made to resolve disputes in the Chesapeake Bay to illustrate the concurrent roles that states and the federal government may play in managing interstate water resources.