This proposal requests funds in support of a ?scoping? workshop to explore the needs and requirements for a community hydrologic modeling activity in hydrology. This activity is tentatively called the Community Hydrologic Modeling Platform (CHyMP) and it is proposed as one of two new major initiatives for the next 5-year phase of the Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI). The goal of CHyMP is to significantly advance hydrologic simulation capabilities via a community modeling activity, including the development, distribution and technical support of common simulation software. The current vision for CHyMP is of a platform that would support several modeling packages for forward modeling, inverse modeling, stochastic modeling, graphical visualization, access to data sources, and other features. This vision will be modified and refined through an initial scoping workshop (proposed here) and two follow-on workshops. An important outcome of CHyMP would be a framework for integrated water cycle modeling that could be applied across scales and for solving complex hydrologic research questions that could not be addressed in its absence. The goal of the first workshop is to survey the range of perspectives on the scope and form that a community hydrologic modeling activity should take. The outcome will be the establishment of a CHyMP working group and a report to the community on the rationale and preliminary strategy for undertaking community modeling in hydrology. Following the scoping and follow-on workshops, we expect that a PI-led research team will make a formal proposal to the NSF for the development and implementation of the platform. The intellectual merit of the proposed workshop is the articulation of the form and requirements for a community hydrologic modeling platform. The broader impacts of the workshop are the potential provision of integrated water cycle modeling tools to the hydrologic and related communities, as well as the new research that these tools will enable.
