The Klamath River Basin, a region along the California-Oregon border, has become a focal point for local and national discussions on water and species management. Water management issues were brought to the forefront when severe drought conditions in 2001 exacerbated competition for scarce water resources and generated conflict among several interests—farmers, anglers (commercial and sport), other recreationists, federal wildlife refuge managers, environmental organizations, and state, local, and tribal governments. Subsequent issues with Klamath Basin fisheries, including events in 2002 and 2006, exacerbated these conflicts. As is true in many regions in the West, the federal government plays a prominent role in the Klamath Basin's water management. This role stems from (1) operation and management of the Bureau of Reclamation's Klamath Water Project; (2) management of federal lands in the basin, including several national wildlife refuges managed by the Fish and Wildlife Service (FWS); and (3) implementation of federal laws, such as the Endangered Species Act (ESA), Clean Water Act (CWA), and National Environmental Policy Act (NEPA). The Klamath Basin Restoration Agreement (KBRA) and the Klamath Hydroelectric Settlement Agreement (KHSA), collectively referred to as the "Klamath agreements" in this report, aim to settle many of the outstanding issues in the basin. The agreements were signed in 2010 by more than 40 groups, including state and non-federal interests. The KBRA defines limits to water allocations for irrigators and wildlife refuges under a range of conditions, and lays out restoration actions, monitoring and other actions that aim to recover fish species and provide economic stability for basin tribes. The KHSA lays out a process that could lead to removal of four non-federal hydroelectric dams currently owned and operated by a private entity. Under the KHSA, the Secretary of the Interior determines whether removal of these dams is in the public interest. Congress has oversight over federal activities in the Klamath and has held hearings and appropriated funding to address issues in the Klamath Basin. In the past, congressional debate has focused on the role of the ESA in water management, the operation of the Klamath Project, and other topics, such as supplemental support for parties impacted by federal policies. Current congressional consideration is likely to focus on the agreements themselves. The agreements require congressional authorization to move forward on some of their most important components, which may result in Congress revisiting previous questions, as well as new ones. The Klamath River Basin (also referred to in this report as the Klamath Basin) drains approximately 16,000 square miles in Oregon and California. It drains into the Klamath River, which originates in southern Oregon and travels 253 miles before emptying into the Pacific Ocean near Crescent City, California. Combined with the Trinity River, the system is the largest in the western United States other than the Sacramento and Columbia rivers in terms of flow and salmon production. However, the basin is also a sparsely populated area with some of the lowest per-capita incomes in either state. The total population is approximately 287,000, and total economic output in the basin was approximately $10 billion as of the late 1990s. Native American tribes account for 6% (15,000) of the basin's total population. For water management purposes, the Klamath Basin is divided into two distinct subbasins. The Upper Basin lies upriver and east of Iron Gate Dam on the Klamath River, and contains Oregon's largest lake, Upper Klamath Lake. The Lower Basin includes nearly 200 miles of the Klamath River between Iron Gate Dam and the Pacific Ocean. Both basins contain smaller lakes, tributaries, and wildlife refuges that also play an important role in water allocation. The Upper Klamath Basin is an area with limited water resources. It represents approximately 50% (8,060 square miles) of the Klamath Basin land area, but accounts for only 12% of its water runoff. Upper basin issues center largely around Upper Klamath Lake (UKL), a large, shallow natural lake covering about 60,000 acres. UKL has an active storage capacity of approximately 500,000 acre feet. It is naturally eutrophic (i.e., high in nutrients) because of its shallow depth and natural sources of nutrients, and these conditions have worsened over the past century in part due to agricultural development. As a result, the lake is now considered to be "hypereutrophic," a condition which can cause excessive algae blooms and, in some instances, harm fish and other resident species. Management of Upper Basin water largely revolves around the Klamath Project, a federal project operated by the Bureau of Reclamation. The Klamath Project diverts Klamath and Lost River flows between Link River Dam, at the outlet of the UKL, and Keno Dam to the Southeast. When it was built in 1905, the project (fed by the Klamath River) converted some lands and waters that had historically been fish habitat into farmland. Today it provides irrigation water for approximately 210,000 acres in the Upper Basin, including an estimated 1,400 farms. The Klamath Project is different from other Reclamation projects because of its reliance on UKL, a natural lake, for project storage. Because of the shallowness of UKL, it is it difficult to store significant amounts of water for irrigation from year to year. As a result, the project is highly dependent on annual precipitation and snowmelt for its water supply. Additionally, in contrast to some Reclamation Projects, there is no hydroelectric component to the Klamath Project, which means that irrigators must look elsewhere for low-cost power for irrigation pumping. Irrigated lands in the upper basin also include approximately 180,000 acres of lands that are not dependent on the Klamath Project for deliveries. This land is located predominantly around the northern part of UKL and on the surrounding tributaries of the Sprague, Williamson, and Wood rivers. Irrigators operating in these areas are often referred to as "off-project" irrigators. Agriculture is a major part of the Klamath Basin's economy. Major crops supported by irrigation in the Upper Basin include wheat, malt barley, potatoes, onions, and alfalfa. According to Reclamation, crops watered by the Klamath Project had an estimated annual value of $156 million in 2007. On off-project lands, water is mainly used to maintain pastures and forage crops. In the late 1990s it was estimated that agriculture accounted for 10% of the jobs and 7.3% of the direct economic activity in the region. As the region's largest industry, agricultural activity also supports other economic sectors. The Upper Klamath Basin also includes six wildlife refuges near the Klamath Project, collectively referred to as the Klamath Basin National Wildlife Refuge Complex (or "Klamath Refuges"). These refuges contain wetlands that are major stopping points for approximately three-quarters of migratory birds on the Pacific Flyway. Additionally, a portion of the irrigation water from the Klamath Project is used downstream to provide water to the Lower Klamath National Wildlife Refuge (NWR) and the Tule Lake NWR, lands that were included as part of the original Klamath Project but that were subsequently converted. (See Figure 1 .) These refuges also have a unique agreement (known as "lease-land farming") in which parts of the refuge are leased out for farming. Two species of Upper Basin fish are listed as endangered under the Endangered Species Act (ESA) and figure prominently into water allocation debates (see Appendix A ). The Lost River and shortnose suckers both live in UKL and were once plentiful enough to support commercial fisheries. After steep declines during the last half of the 20 th century, they were listed under the Endangered Species Act in 1988. Their decline has been attributed to factors such as poor water quality, habitat loss and degradation, dams on UKL tributaries, and entrainment in irrigation diversions. Suckers are particularly important to the Klamath Tribe, who use the fish for ceremonial purposes, but historically relied on the fish for sustenance. Upper Basin tribes and recreational anglers also reportedly used to catch salmon. However, Iron Gate Dam, constructed in 1962, permanently blocked upstream passage of salmon. Previous studies by government biologists have concluded that historically, significant runs of Chinook and coho salmon existed north of Iron Gate Dam and on the tributaries of Upper Klamath Lake, although some dispute these conclusions. The Lower Klamath Basin lies below and west of Iron Gate Dam. The Klamath River at this point runs unobstructed to the Pacific Ocean. Where the Lower Basin represents approximately half (7,470 square miles) of the basin's land area, it is the origin of 88% of its runoff. Much of this water flows into the Lower Klamath from four tributaries: the Shasta, Scott, Salmon, and Trinity rivers. As in the Upper Basin, agriculture is a prominent activity in the Lower Basin. In particular, irrigated agriculture uses water from the Shasta, Scott, and Trinity rivers. The number of Lower Basin farms and their associated production value, however, are less than half of that found in the Upper Basin. In addition to agriculture, much of the acreage in the Lower Basin is managed by the U.S. Forest Service for multiple purposes (e.g., timber production, recreation, fish and wildlife habitat, etc.). The Lower Klamath River provides habitat for 13 anadromous fish species, including three species of salmon: coho salmon, Chinook salmon, and steelhead (see Appendix A ).