This model simulates a mixed-media storage facility, which accounts for changing quantities of solids and water over time. This kind of model is useful in tailings facilities found at mines and also for simulating sediment accumulation in reservoirs. The inflow to storage might be a slurry that has a high concentration of solids or just natural inflows with high sediment content. Either way, the basic concepts are the same. This model simulates the reduction in water capacity as the solids accumulate and account for entrained water in the solids so that it adequately accounts for the pooled water. Finally, this model manages storage and overflows using a geometric relationship of elevation-area-volume of the storage facility.