As Russia transitions from communism to a free market society, it is left to deal with a host of environmental problems. Of particular concern in the Pronya River watershed is the quality of drinking water. In addition to pollution from industry, agriculture, and urban sources, nuclear fallout from the Chernobyl accident adds to the environmental challenges. Operation Twinkling Star is a joint project of the United States and Russia aimed at linking people, scientists, and companies in solving watershed-scale environmental problems one watershed at a time. The immediate goal is to improve drinking water quality (surface and groundwater). Larger goals are to apply the lessons learned from this case study to other regions.