Understanding how routing modifications influence survival of juvenile salmon is complex because reach-specific survival and routing at key river junctions in the North Delta each have a different relationship with river flow. Therefore, to facilitate understanding of how routing modifications at key river junctions influence through-Delta survival, we developed this spreadsheet model to allow managers to explore the potential effects of modifying routing. The purpose is to provide a screening tool that allows managers to quickly run many different scenarios to understand how both routing and route-specific survival interact to affect overall survival through the Delta. This tool may be useful in narrowing the range of potential scenarios that might be investigated using more complex modeling techniques (e.g., agent-based models) and eventually evaluated with field studies.