Congress addresses numerous water issues annually. Issues range from responding to natural disasters, such as droughts and floods, to improving the nation's water resource and water quality infrastructure, and protecting fish, wildlife, and other aquatic resources. Many congressional committees address these issues and are involved in legislating, funding, and overseeing the water-related activities of numerous federal agencies. More than two centuries of such involvement have resulted in a complex web of federal activities related to water. As a result, Congress often faces challenges related to overlap and gaps in federal water resource activities and in coordination and consistency among federal programs. Further, many federal authorities are discretionary or funded by discretionary appropriations. Consequently, there can be a significant difference between what federal agencies are authorized to do and what they are doing, and no one committee in Congress oversees this dichotomy. The responsibility for development, management, protection, and allocation of the nation's water resources is spread among federal, state, local, tribal, and private interests. Despite multiple calls for the coordination of federal water-related activities, observers seldom focus on the origins of laws and policies authorizing myriad federal activities. The purpose of this report is to provide insight into the congressional involvement in establishing, overseeing, and funding federal water-related activities. Thus, the report focuses on the complexity of federal activities related to water. It aims to serve as a guide to federal water-related activities, including the administering agency (or agencies), the primary or overarching authorities for such activities, and House and Senate committee jurisdictions. In most cases, the primary authorities listed are authorizing statutes and accompanying U.S. Code citations; in some instances, constitutional or other authorities are provided. This analysis does not cover every aspect of federal water policy. Instead, the authors have attempted to address the major federal activities authorized by Congress that affect water resource development, management, protection, and use in the United States. Similarly, this analysis does not cover every aspect of House and Senate committee jurisdiction affecting water issues. For definitive evaluation of committee jurisdictions related to water, the views of the House and Senate Parliamentarian Offices are official. Lastly, programs known to have expired and for which reauthorization legislation is pending may be noted; however, given the breadth of the report and constant executive and legislative branch activity, it is not possible to provide comprehensive status reports for all entries. The federal government has been involved in water resources development since the earliest days of the nation's creation. Congress first directed water resource improvements to facilitate navigation, then to reduce flood damages and expand irrigation in the West. For much of the 20 th century, the federal government was called upon to assist and pay for a multitude of water resource development projects—large-scale dams such as Hoover and Grand Coulee, as well as navigation locks throughout the country's largest rivers. In recent decades, Congress has enacted legislation to regulate water quality; protect fish, wildlife, and threatened and endangered species; manage floodplain development; conduct research; and facilitate water supply augmentation via support for water reclamation and reuse facilities and desalination. Congress maintains an active role in overseeing implementation of this legislation, as well as enacting new laws and appropriating funding for water resources activities. Specific federal water laws have been enacted for the diverse purposes noted above. Development and implementation of these laws have involved the action of numerous congressional committees and federal agencies. At the congressional level, this action has resulted in a set of diverse and sometimes overlapping committee jurisdictions dealing with various aspects of water policy and addressing the interests of differing constituencies. At the executive branch level, this has resulted in many agencies and organizations being involved in different and sometimes overlapping aspects of federal water policy. The activities identified in this report fall into the jurisdiction of numerous congressional standing committees (and generally exclude appropriations and other committees in the relevant chambers that deal with banking, taxes, and finance issues.) Similarly, the activities identified in this report are addressed in some form by many federal executive branch agencies. The following tables describe federal water-related activities and programs in the United States and identify the primary administering federal agency(ies), primary authorities, and examples of congressional committees of jurisdiction for each agency activity or program. The tables are arranged under broad areas, subtopics, and topic terms. The four areas covered by the report are as follows: Water Resources Development, Management, and Use ; Water Quality, Protection, and Restoration ; Water Rights and Allocation ; and Research and Planning . Each thematic area begins with a brief introduction and is followed by a table(s) of relevant agencies, activities and programs, and House and Senate committees of jurisdiction. Each table covers more focused areas of water issues—subtopics—based on agency function and the historical development of federal water programs. In organizing these tables, a series of topic terms was developed under which both members of the general public and those more familiar with water policy might categorize federal water-related activities. These topic terms were determined by the CRS analysts and legislative attorneys involved in developing the report. The "Water Resources Development, Management, and Use" theme includes subtopics that relate to supply and reservoir development, drought and flood management, hydropower, and navigation. The "Water Quality, Protection, and Restoration" theme addresses issues relating to water quality and aquatic resources protection and management, including selected regional aquatic ecosystem restoration authorities. The "Water Rights and Allocation" theme addresses water allocation and interstate compacts, river basin commissions, federal reserved water rights, and tribal water rights. The "Research and Planning" theme includes subtopics related to research and data collection, such as water cycle and climate change research, water-related technologies, and watershed planning. Significant overlaps occur both within and among the different categories. This analysis generally excludes marine or ocean issues and international and boundary water issues, except for jointly managed dams at the U.S.-Mexican border and Environmental Protection Agency (EPA) programs along the U.S.-Mexican border. Additionally, Congress has established various economic development programs that include water supply and/or treatment projects among the categories of purposes eligible for federal assistance; however, this report does not include programs for which water-related activities are not the major focus. Also excluded are broad environmental remediation or waste management statutes, such as the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and the Solid Waste Disposal Act. Water activities affecting Indian tribes are also not uniformly addressed in the accompanying tables but instead are covered where they are known to interact with broader federal agency water-related programs and activities, such as water supply development and water quality infrastructure. Because federal environmental laws, such as the Endangered Species Act and the National Environmental Policy Act, apply to all federal agencies, federal agency activities under those laws are not identified in this report. Appendix A discusses considerations in determining House and Senate committee jurisdictions and provides an example of the complexity in water topics and jurisdictional coverage. Appendix B and Appendix C present the official language from House Rule X and Senate Rule XXV, respectively, as indicators of congressional jurisdiction over water resources. Both the House and the Senate tables also address subcommittee jurisdiction, and the Senate table provides information on executive branch nominations handled by Senate committees. Appendix D provides a glossary of abbreviations for federal agencies and House and Senate committees. Program abbreviations generally are spelled out where they first occur in each table. In sum, the nine tables that make up the body of the report define water based on the topic terms determined by CRS. These tables underscore the intricacy of the federal programs affecting water resource development, management, protection, and use in the United States. As apparent throughout the tables, numerous standing committees in the House and Senate have jurisdiction over various components of federal water policy; moreover, committees listed here generally exclude the extensive responsibilities of the appropriations committees in both chambers, as well as the direct and indirect activities of other committees in the relevant chambers that deal with banking, taxes, and finance issues. Historically, the federal government played a large role in development of the nation's water resources—in particular constructing large water resource infrastructure projects (e.g., canals, locks, levees, and dams)—for navigation, flood damage reduction, and irrigation water supply in the West. The largest federal dams typically serve multiple purposes, including those noted above, as well as producing hydropower and providing water supplies for municipal and industrial uses. More recently, Congress has authorized activities and programs to augment water supplies via water conservation programs, including groundwater recharge (aquifer storage and recovery), and water reclamation and reuse programs, including desalination. This section focuses on federal activities related to water resource development, management, and use and includes three tables: Table 1 lists activities related to water supply and reservoir development and includes topic areas such as dams and dam safety; general water supply development; groundwater supply; irrigation assistance; rural water supply; water conservation; and water reclamation, reuse and desalination. Table 2 lists activities related to drought and flood management and includes topic areas such as drought planning, mitigation, and response; emergency flood response; flood damage reduction; and flood mitigation. Table 3 lists activities related to hydropower and navigation and includes topic areas such as federal hydropower development; nonfederal hydropower development; and navigation. Federal efforts to protect and improve water quality and water resources range from technical and financial assistance programs to help communities build sewage treatment and drinking water treatment works, to regulatory programs for preventing or controlling water pollution. Most federal programs focus on surface water quality, while states have a dominant role in matters related to groundwater protection. One exception is where Congress has authorized EPA to regulate the underground injection of fluids to protect underground sources of drinking water. In addition to protecting and improving water quality, Congress has enacted numerous bills to manage, protect, and restore aquatic ecosystems—including estuaries, and wetlands.