Under the auspices of the ICPRB, a group of citizens organizes the Citizens Council for a Clean Potomac (1956). As the U.S. Public Health Service declares the Potomac River unsafe for swimming, ICPRB estimates that on the average, 60 million cubic feet of sediment is deposited annually within the metropolitan Washington reach of the Potomac estuary (1957). Chairman Harold A. Kemp indicates Potomac River pollution has reached a "critical condition" with urgent need for additional sewage treatment facilities. By 1958, ICPRB is gathering and tabulating information from about 85 stream sampling stations operated by cooperating agencies, municipalities and industries. The following year, ICPRB publishes its first "Potomac River Water Quality Network," holds a "first-of-its-kind" silt control conference and sponsors a study of sediment sources in the basin with the U.S. Geological Survey.   1960s - In 1963, ICPRB issues two reports on sediment sources and an urban sediment control program.   1970s - ICPRB's Compact is amended in 1970, extending its authority to include water supply and water-related land use. In 1975, an ICPRB conference focuses on rising dollar and energy costs associated with Washington, D.C. metro area sewage treatment.   1980s - ICPRB initiates regional discussion of the problem posed by invasive aquatic weed, hydrilla (1983). After Maryland (1985) and the District of Columbia (1986) initiate a phosphate detergent bans, ICPRB recommends (1987) expanding such bans basin-wide.  1990s - Maryland, West Virginia and ICPRB sign (1993) cooperative agreement on program to restore water quality to the North Branch.  2000s– In 2001, the ICPRB combined decades of data into a consistent and usable format for researchers and those working on the watershed in the Tidal Potomac Integrative Analysis Project. In 2002, ICPRB's successful American Shad Restoration Project is completed, restoring the population of this historically significant fish that once flowed freely in the Potomac but had been decimated by pollution, overfishing, and blockage over the past century. In 2004, along with other partners in the basin, the Commission organizes and leads the formation of a voluntary partnership between water utilities and state and federal agencies known as the Potomac River Basin Drinking Water Source Protection Partnership which will focus on protecting the water quality of the river as the source of drinking water for millions of people that live in the basin.