Wetlands provide a variety of important landscape functions, many of which arise from their role as distributed water storage. Geographically isolated wetlands, which are the most abundant and most imperiled US wetlands, are often assumed to be hydrological dead-ends because they are commonly closed depressions. This assumption has greatly influenced the legal protections they receive, which now insist on permanent connections to navigable waters. In this talk, evidence will be presented that indicates that depressional wetlands are not hydrological dead ends, and that they serve critical storage and release functions in their landscapes sustained by groundwater connectivity and amplified by activated fill-and-spill dynamics.