2012 Annual Report 1a.Objectives (from AD-416): 1) Apply the modified Penn State Integrated Hydrology Modeling (PIHM) system over RCEW using all available data;. 2)Selectively reduce input data to determine the minimum input forcing data required to achieve acceptable simulation accuracy;. 3)Recommend augmentation of existing measurement facilities and models that would be required to achieve this level of simulation accuracy over the larger Great Basin region. 1b.Approach (from AD-416): The scientist funded through this project will work with university and ARS hydrologists to integrate the NWRC snow model into the PIHM system, and implement and evaluate the modified PIHM system at the RCEW. Located at the NWRC in Boise Idaho, the scientist would work collaboratively with the WATERS team to evaluate the accuracy and reliability of PIHM simulations using complete and successively limited RCEW forcing data. The 48-year data record will allow testing over a full range of climate conditions. 3.Progress Report: It was not funded. A manuscript was revised twice for Water Resources Research, and we are still awaiting notice of acceptance. A new manuscript, "Evaluation of distributed hydrologic impacts of temperature-index and energy-based snow model simulations" is being prepared for submission to Advances in Water Resources. This agreement was established in support of Objective 3 of the in-house project, the goal being to expand integrated snow hydrology modeling to larger scales, coupling to belowground processes, including wind effects on precipitation input, and to help incorporate snow-related processes into ARS watershed and management simulation models.