The US Global Water Cycle program is a new initiative that addresses the needs of the joint USGCRP/ CCRI program. Since the publication of the Hornberger report more than a year ago, federal agencies have been working together to develop a coordinated program to address both the priorities outlined in the Hornberger report and to meet the research needs of the USGCRP and the CCRI. The program brings together expertise from atmospheric, hydrologic, water resource and to some extent oceanographic sciences to address climate and water issues. Demands for water continue to increase due to population growth, industrial development and urban expansion, while precipitation and water availability vary widely from year to year. The development of a new coordinated federal program is challenging because new funding is limited and a number of agencies already have long-standing programs to deal with specific water issues.

This presentation will review the needs for water cycle research considering the critical role of the water cycle as a source of climate forcing and feedback, and as a source of new models, information and technologies for more efficient water management. It will set the stage for more detailed descriptions of US water cycle activities that are being undertaken in different agencies and will outline the integrated planning and coordination efforts that are underway in the USGCRP/ CCRI. The contributions of these coordinated activities to international water programs through the World Climate Research Programme and other international activities will also be discussed.