Calite model is an interactive screening model planned and managed by the state water project (SWP) and the Central Valley Project (CVP) in California. It simulates the hydrology of the Central Valley, reservoir operation and delivery allocation decisions to SWP and CVP, delta salinity response to changes in river flow and outlet, and resident ecosystem index. The power of filtering models like callite is the ability to quickly simulate system operations and merge changes relatively easily. The current version of calite simulates the operation of the system on a monthly basis. On the latest modeling computer, it takes about 6 minutes (compared with 30 minutes of calsim), recording a full 82 years of records (water year 1922-2003). Scenarios can be run using a variety of different user specified parameters related to hydrometeorology, requirements, facilities and infrastructure, regulations, and system operations. Through the integrated post-processing tools of the model, we can observe, compare and analyze the results.