Decision Making under Deep Uncertainty (DMDU) techniques have been used by Reclamation since the Colorado River Basin Water Supply and Demand Study (2012) to explore how unpredictable changes to streamflow, demands, system requirements, and stakeholder priorities interact to impact the management of the Colorado River. DMDU methods are intended to augment traditional risk management approaches by subjecting planning tools like the Colorado River Simulation System (CRSS) model to a large range of potential futures, without attaching explicit likelihoods to individual scenarios. The large envelope of potential future scenarios creates a significant computational burden for the analysis of potential new policies for the Colorado River — including the continued operations of Lake Powell and Lake Mead post-2026. This presentation details recent large-scale RiverSmart experiments designed to evaluate different policy structures across multiple objectives and a broadly defined range of future conditions.