The Chesapeake Bay is the largest of the nation’s estuaries, measuring nearly 200 miles long and 35 miles wide at its widest point and, with its tributaries, the bay covers more than 4,500 square miles. However, the bay is relatively shallow, averaging only 21 feet deep. Roughly half of the bay’s water comes from the Atlantic Ocean, and the other half is freshwater that drains from the land and enters the bay through its many rivers and streams in the watershed basin. The Susquehanna River, which flows through Maryland, New York, and Pennsylvania, provides about 50 percent of the freshwater that enters the bay. As shown in figure 1, the bay’s watershed covers 64,000 square miles and spans parts of six states—Delaware, Maryland, New York, Pennsylvania, Virginia, and West Virginia—and the District of Columbia. The Chesapeake Bay is also biologically diverse, providing habitat for a wide variety of fish, shellfish, other animals, and plants. Blue crab, ducks, herring, oysters, shad, and striped bass are just some of the resources that live in or on the bay. Over time, the bay’s ecosystem has deteriorated. The bay’s “dead zones”— where too little oxygen is available to support fish and shellfish—have increased, and many species of fish and shellfish have experienced major declines in population. The deterioration has occurred primarily because of excess amounts of nutrients entering the bay, which damage species and plant populations; the single largest source of these pollutants is agricultural runoff. Overharvesting key species, such as oysters and crabs, has also contributed to the deterioration of the ecosystem. In addition, population growth and development have further stressed the ecosystem. For example, in the past decade, the amount of land in the watershed covered by impervious surfaces—surfaces through which water cannot flow—increased by about 41 percent, increasing the amount of polluted runoff that enters into streams and rivers and eventually runs into the bay. With a very high land-to-water ratio, the bay is particularly sensitive to activities on land. Figure 2 shows some of the land activities that contribute to pollution in the bay’s ecosystem. The decline in the bay’s living resources has been cause for a great deal of public and political attention. Efforts to manage the bay’s ecosystem and protect its living resources began as early as the 1930s and have continued through the present. In 1980, Maryland and Virginia, later joined by Pennsylvania, established the Chesapeake Bay Commission to serve as an advisory body on the Chesapeake Bay to their state legislatures and as a liaison to Congress. On December 9, 1983, the Governors of Maryland and Virginia; the Lieutenant Governor of Pennsylvania; the Mayor of the District of Columbia; the Administrator of EPA; and the Chair of the Chesapeake Bay Commission signed the first Chesapeake Bay agreement. Their agreement resulted in the Chesapeake Bay Program, a partnership that directs and conducts the restoration of the bay. The signatories to the agreement reaffirmed their commitment to restore the bay in 1987 and again in 1992. They signed the most current agreement, Chesapeake 2000, on June 28, 2000. Chesapeake 2000 envisions an ecosystem with abundant, diverse populations of living resources fed by healthy streams and rivers that sustain strong local and regional economies and a unique quality of life. The agreement has served as the Bay Program’s strategic plan, and it outlines five broad goals and 102 commitments for the restoration effort. Appendix II lists the goals and commitments outlined in Chesapeake 2000. The Bay Program, led by the Chesapeake Executive Council, has many partners, including federal agencies, states, academic institutions, and others (see app. III for a list of partners). While the Chesapeake Bay Program is a voluntary partnership among the states and the federal government, some activities of the Chesapeake Bay Program are implemented to meet the requirements of federal or state law. For example, the responsibility to establish water quality standards is both a commitment under the Chesapeake 2000 agreement and a requirement under the federal Clean Water Act. The Bay Program has seven committees and eight subcommittees, which form the organizational and planning structure for the restoration effort. In addition, the subcommittees have many work groups that plan and implement various aspects of the restoration effort. The organizational structure of the Bay Program is shown in figure 3. As the only federal signatory to the Chesapeake Bay agreements, EPA is responsible for spearheading the federal effort within the Bay Program through its Chesapeake Bay Program Office. Amendments to the Clean Water Act direct the Chesapeake Bay Program Office to provide support to the Chesapeake Executive Council. Specifically, the Chesapeake Bay Program Office is to, among other things, develop and make available information about the environmental quality and living resources of the Chesapeake Bay ecosystem; in cooperation with appropriate federal, state, and local authorities, help the signatories to the Chesapeake Bay agreement develop and implement specific plans to carry out their responsibilities; and coordinate EPA’s actions with those of other appropriate entities to develop strategies to improve the water quality and living resources in the Chesapeake Bay ecosystem. In addition, the Administrator of EPA, in coordination with other members of the Chesapeake Executive Council, must ensure that management plans are developed and that the signatories implement the plans to achieve and maintain, among other things, (1) the nutrient goals for the quantity of nitrogen and phosphorus entering the Chesapeake Bay and its watershed and (2) the water quality requirements necessary to restore living resources in the Chesapeake Bay ecosystem. The amendments to the Clean Water Act also directed the Administrator of EPA to submit a report to Congress every 5 years on the condition of the bay’s ecosystem. Although the Bay Program has established 101 measures, it has not yet developed an integrated approach that would allow it to translate these individual measures into an assessment of overall progress toward achieving the five broad restoration goals outlined in Chesapeake 2000. Instead, the Bay Program’s measures either assess progress toward achieving the restoration commitments that are quantifiable or provide information for making management decisions. The Bay Program has recognized that it may need an integrated approach to assess the overall progress of the restoration effort and established a task team to undertake this effort. The Bay Program has established 101 measures, of which 46 are appropriate for assessing progress made in achieving 18 of the 21 quantifiable commitments contained in Chesapeake 2000. The number of measures associated with each of these commitments varies; the more complex the assessment the more measures the Bay Program has developed and uses to assess progress. For example, assessing progress toward the commitment of correcting the nutrient- and sediment-related problems in the Chesapeake Bay and its tidal tributaries by 2010 under the Water Quality Protection and Restoration goal is complex, requiring the measurement of several pollutants and various aspects of water quality. The Bay Program uses 17 measures to assess progress for this commitment. In contrast, it is less complex to assess the commitment under the Sound Land Use goal to, by 2010, expand by 30 percent the system of public access points to the bay, its tributaries, and related resource sites in an environmentally sensitive manner. For this commitment, the Bay Program uses only one measure to track the number of new and enhanced public access sites within the Chesapeake Bay watershed. According to the Chesapeake Bay Program Office, because no other restoration effort had developed measures that they could use, the program had to develop nearly all of the underlying science and methodologies for their measures. In addition, to ensure the appropriateness of these measures, the Chesapeake Bay Program Office requires a rigorous review of all of the measures before they are adopted. For the most part, our expert panel agreed that the Bay Program has established appropriate measures to assess specific aspects of the restoration effort. Several members of the Bay Program’s Scientific and Technical Advisory Committee echoed this view. The remaining three quantifiable commitments, for which the Bay Program has not yet established any measures, include the following: By 2010, establish a goal of implementing plans to preserve key wetlands while addressing surrounding land use in 25 percent of the land area of each state’s bay watershed. By 2010, the District of Columbia, working with its watershed partners, will reduce pollution loads to the Anacostia River in order to eliminate public health concerns and achieve the living resource, water quality, and habitat goals of Chesapeake 2000 and past agreements. By 2003, develop partnerships with at least 30 interpretive sites to enhance their presentation of bay-related themes. The Bay Program has also developed 55 other measures to provide information it needs to make management decisions. For example, under the Water Quality Protection and Restoration goal, the Bay Program has made a commitment to assess the effects of airborne nitrogen compounds and chemical contaminants in the bay ecosystem and to help establish reduction goals for these contaminants. To help inform decision making for this commitment, the Bay Program has a measure for estimated vehicle emissions compared with vehicle miles traveled. In addition, for the commitment under the Living Resource Protection and Restoration goal to restore fish passage to more than 1,357 miles of river, the Bay Program has two measures that provide information about fish population levels. The Bay Program also uses three measures—the number of residents in the Chesapeake Bay watershed, the relationship between this population and the amount of municipal wastewater flow, and the volume of river water flowing into the Chesapeake Bay—to track general information about the Chesapeake Bay watershed. While the Bay Program has established measures to assess progress made in meeting some of the individual commitments of Chesapeake 2000, it has not developed an approach that can be used to assess progress toward achieving the five broad restoration goals.