Hydrologic Sciences, as a distinct, new, interdisciplinary Geoscience, was conceived in 1991 in a report of the National Research Council called "Opportunities in Hydrologic Sciences". A new initiative by the Directorate for Geosciences (GEO) called GEO-2000 offers a unique opportunity for the broad hydrology community to take steps to develop a comprehensive, long ten-n plan which can serve as a basis to enhance base funding in hydrologic sciences at NSF. Simultaneously, this plan would provide a basis for taking stock of ma or accomplishments and advancements which would result from an enhanced funding base, and identifying future needs. This proposal addresses how such a plan can be developed and implemented within a broad scientific framework involving three steps. The first step is to prepare a 'concept paper' or a 'science plan'. The second step is to organize a small workshop in which the science plan will serve as a discussion document. The workshop will send its 'initial recommendations' to GEO by February 28, 1999. The third step is to widely publicize the outcome of the first two steps, and seek input from the broad national and international hydrology community. This third step will serve as the basis for making appropriate revisions into initial recommendations, preparing a set of 'revised recommendations' for the 'GEO-2000 report' by the fall of 1999, and making plans for future action items beyond GEO-2000.